Artykuły w czasopismach: „Collage covalent”

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DIAB, Mohammad, Jiann-Jiu WU i David R. EYRE. "Collagen type IX from human cartilage: a structural profile of intermolecular cross-linking sites". Biochemical Journal 314, nr 1 (15.02.1996): 327–32. http://dx.doi.org/10.1042/bj3140327.

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Type IX collagen, a quantitatively minor collagenous component of cartilage, is known to be associated with and covalently cross-linked to type II collagen fibrils in chick and bovine cartilage. Type IX collagen molecules have also been shown to form covalent cross-links with each other in bovine cartilage. In the present study we demonstrate by structural analysis and location of cross-linking sites that, in human cartilage, type IX collagen is covalently cross-linked to type II collagen and to other molecules of type IX collagen. We also present evidence that, if the proteoglycan form of type IX collagen is present in human cartilage, it can only be a minor component of the matrix, similar to findings with bovine cartilage.

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Wu, J. J., D. R. Eyre i H. S. Slayter. "Type VI collagen of the intervertebral disc. Biochemical and electron-microscopic characterization of the native protein". Biochemical Journal 248, nr 2 (1.12.1987): 373–81. http://dx.doi.org/10.1042/bj2480373.

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The collagen framework of the intervertebral disc contains two major fibril-forming collagens, types I and II. Smaller amounts of other types of collagen are also present. On examination of the nature and distribution of these minor collagens within bovine disc tissue, type VI collagen was found to be unusually abundant. It accounted for about 20% of the total collagen in calf nucleus pulposus, and about 5% in the annulus fibrosus. It was discovered by serially digesting disc tissue with chondroitin ABC lyase and Streptomyces hyaluronidase that native covalent polymers of type VI collagen could be extracted. Electron micrographs of this material prepared by rotary shadowing revealed the characteristic dimensions of tetramers and double tetramers of type VI molecules, with their central rods and terminal globular domains. Molecular-sieve column chromatography on agarose under non-reducing non-denaturing conditions gave a series of protein peaks with molecular sizes equivalent to the tetramer, double tetramer and higher multimers. On SDS/polyacrylamide-gel electrophoresis after disulphide cleavage, these fractions of type VI collagen all showed a main band at Mr 140,000 and four lesser bands between Mr 180,000 and 240,000. On electrophoresis without disulphide cleavage in agarose/2.4% polyacrylamide only dimeric (six chains) and tetrameric (12 chains) forms of type VI molecules were present. The ability to extract all the type VI collagen of the tissue in 4 M-guanidinium chloride, and absence of aldehyde-mediated cross-linking residues on direct analysis, showed that, in contrast with most matrix collagens, type VI collagen does not function as a covalently cross-linked structural polymer.

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Blumberg, B., L. I. Fessler, M. Kurkinen i J. H. Fessler. "Biosynthesis and supramolecular assembly of procollagen IV in neonatal lung." Journal of Cell Biology 103, nr 5 (1.11.1986): 1711–19. http://dx.doi.org/10.1083/jcb.103.5.1711.

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The rate of biosynthesis of procollagen IV, the principal collagen of basement membranes, and the concentration of specific RNAs coding for procollagen IV were measured in neonatal rat lungs. Both decreased sharply at birth and then recovered again a few days later. The supramolecular assembly of procollagen IV was followed in neonatal rat, mouse, and chick lungs, which actively elaborate endothelial and alveolar basement membranes, and in chick embryo gizzard which is rich in smooth muscle. The tetramer of four procollagen IV molecules linked covalently through their amino ends was isolated as an assembly intermediate from all these tissues. While noncovalent association of the carboxyl ends of two procollagen IV molecules occurred readily, the subsequent establishment of covalent cross-links was substantially slower in the junctional complexes of the carboxyl ends than of the amino ends. Both disulfide bonds and other, unidentified covalent links formed. The six component carboxyl peptides of a junctional complex became progressively covalently linked into two kinds of carboxyl peptide pairs. We conclude that both amino-linked tetramers and carboxyl-linked dimers of procollagen IV molecules are intermediates in the biological assembly of the collagen networks of these basement membranes.

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Ao, Haiyong, Youtao Xie, Honglue Tan, Shengbing Yang, Kai Li, Xiaodong Wu, Xuebin Zheng i Tingting Tang. "Fabrication and in vitro evaluation of stable collagen/hyaluronic acid biomimetic multilayer on titanium coatings". Journal of The Royal Society Interface 10, nr 84 (6.07.2013): 20130070. http://dx.doi.org/10.1098/rsif.2013.0070.

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Layer-by-layer (LBL) self-assembly technique has been proved to be a highly effective method to immobilize the main components of the extracellular matrix such as collagen and hyaluronic acid on titanium-based implants and form a polyelectrolyte multilayer (PEM) film by electrostatic interaction. However, the formed PEM film is unstable in the physiological environment and affects the long-time effectiveness of PEM film. In this study, a modified LBL technology has been developed to fabricate a stable collagen/hyaluronic acid (Col/HA) PEM film on titanium coating (TC) by introducing covalent immobilization. Scanning electron microscopy, diffuse reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the PEM film. Results of Sirius red staining demonstrated that the chemical stability of PEM film was greatly improved by covalent cross-linking. Cell culture assays further illustrated that the functions of human mesenchymal stem cells, such as attachment, spreading, proliferation and differentiation, were obviously enhanced by the covalently immobilized Col/HA PEM on TCs compared with the absorbed Col/HA PEM. The improved stability and biological properties of the Col/HA PEM covalently immobilized TC may be beneficial to the early osseointegration of the implants.

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Wu, Yuexin, i Gaoxiang Ge. "Complexity of type IV collagens: from network assembly to function". Biological Chemistry 400, nr 5 (27.05.2019): 565–74. http://dx.doi.org/10.1515/hsz-2018-0317.

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Abstract Collagens form complex networks in the extracellular space that provide structural support and signaling cues to cells. Network-forming type IV collagens are the key structural components of basement membranes. In this review, we discuss how the complexity of type IV collagen networks is established, focusing on collagen α chain selection in type IV collagen protomer and network formation; covalent crosslinking in type IV collagen network stabilization; and the differences between solid-state type IV collagen in the extracellular matrix and soluble type IV collagen fragments. We further discuss how complex type IV collagen networks exert their physiological and pathological functions through cell surface integrin and nonintegrin receptors.

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SEYER, JEROME M., i ANDREW H. KANG. "Covalent Structure of Collagen." Annals of the New York Academy of Sciences 460, nr 1 Biology, Chem (grudzień 1985): 503–5. http://dx.doi.org/10.1111/j.1749-6632.1985.tb51223.x.

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Colman, RW, WR Figures, LM Scearce, AM Strimpler, FX Zhou i AK Rao. "Inhibition of collagen-induced platelet activation by 5'-p- fluorosulfonylbenzoyl adenosine: evidence for an adenosine diphosphate requirement and synergistic influence of prostaglandin endoperoxides". Blood 68, nr 2 (1.08.1986): 565–70. http://dx.doi.org/10.1182/blood.v68.2.565.565.

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Abstract The relative roles of platelet autacoids such as adenosine diphosphate (ADP), prostaglandin endoperoxides, and thromboxane A2 (TXA2) in collagen-induced platelet activation are not fully understood. We reexamined this relationship using the ADP affinity analogue, 5'-p- fluorosulfonylbenzoyl adenosine (FSBA), which covalently modifies a receptor for ADP on the platelet surface, thereby inhibiting ADP- induced platelet activation. Collagen-induced shape change, aggregation, and fibrinogen binding were each fully inhibited under conditions in which FSBA is covalently incorporated and could not be overcome by raising the collagen used to supramaximal concentrations. In contrast, TXA2 synthesis stimulated by collagen under conditions that produced maximum aggregation was only minimally inhibited by FSBA. Since covalent incorporation of FSBA has been previously shown to specifically inhibit ADP-induced activation of platelets, the present study supports the contention that ADP is required for collagen-induced platelet activation. Under similar conditions, indomethacin, an inhibitor of cyclooxygenase, inhibited collagen-induced shape change, indicating that endoperoxides and/or TXA2 also play a role in this response. Shape change induced by low concentrations (10 nmol/L) of the stable prostaglandin endoperoxide, azo-PGH2, was also inhibited by FSBA. These observations indicate a role for ADP in responses elicited by low concentrations of endoperoxides. However, at higher concentrations of azo-PGH2 (100 nmol/L), inhibition by FSBA could be overcome. Thus, the effect of collagen apparently has an absolute requirement for ADP for aggregation and fibrinogen binding and for both ADP and prostaglandins for shape change. Aggregation and fibrinogen binding induced by prostaglandin endoperoxides also required ADP as a mediator, but ADP is not absolutely required at high endoperoxide concentration to induce shape change.

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Colman, RW, WR Figures, LM Scearce, AM Strimpler, FX Zhou i AK Rao. "Inhibition of collagen-induced platelet activation by 5'-p- fluorosulfonylbenzoyl adenosine: evidence for an adenosine diphosphate requirement and synergistic influence of prostaglandin endoperoxides". Blood 68, nr 2 (1.08.1986): 565–70. http://dx.doi.org/10.1182/blood.v68.2.565.bloodjournal682565.

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The relative roles of platelet autacoids such as adenosine diphosphate (ADP), prostaglandin endoperoxides, and thromboxane A2 (TXA2) in collagen-induced platelet activation are not fully understood. We reexamined this relationship using the ADP affinity analogue, 5'-p- fluorosulfonylbenzoyl adenosine (FSBA), which covalently modifies a receptor for ADP on the platelet surface, thereby inhibiting ADP- induced platelet activation. Collagen-induced shape change, aggregation, and fibrinogen binding were each fully inhibited under conditions in which FSBA is covalently incorporated and could not be overcome by raising the collagen used to supramaximal concentrations. In contrast, TXA2 synthesis stimulated by collagen under conditions that produced maximum aggregation was only minimally inhibited by FSBA. Since covalent incorporation of FSBA has been previously shown to specifically inhibit ADP-induced activation of platelets, the present study supports the contention that ADP is required for collagen-induced platelet activation. Under similar conditions, indomethacin, an inhibitor of cyclooxygenase, inhibited collagen-induced shape change, indicating that endoperoxides and/or TXA2 also play a role in this response. Shape change induced by low concentrations (10 nmol/L) of the stable prostaglandin endoperoxide, azo-PGH2, was also inhibited by FSBA. These observations indicate a role for ADP in responses elicited by low concentrations of endoperoxides. However, at higher concentrations of azo-PGH2 (100 nmol/L), inhibition by FSBA could be overcome. Thus, the effect of collagen apparently has an absolute requirement for ADP for aggregation and fibrinogen binding and for both ADP and prostaglandins for shape change. Aggregation and fibrinogen binding induced by prostaglandin endoperoxides also required ADP as a mediator, but ADP is not absolutely required at high endoperoxide concentration to induce shape change.

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Gwiazda, Marcin, Sheetal K. Bhardwaj, Ewa Kijeńska-Gawrońska, Wojciech Swieszkowski, Unni Sivasankaran i Ajeet Kaushik. "Impedimetric and Plasmonic Sensing of Collagen I Using a Half-Antibody-Supported, Au-Modified, Self-Assembled Monolayer System". Biosensors 11, nr 7 (8.07.2021): 227. http://dx.doi.org/10.3390/bios11070227.

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This research presents an electrochemical immunosensor for collagen I detection using a self-assembled monolayer (SAM) of gold nanoparticles (AuNPs) and covalently immobilized half-reduced monoclonal antibody as a receptor; this allowed for the validation of the collagen I concentration through two different independent methods: electrochemically by Electrochemical Impedance Spectroscopy (EIS), and optically by Surface Plasmon Resonance (SPR). The high unique advantage of the proposed sensor is based on the performance of the stable covalent immobilization of the AuNPs and enzymatically reduced half-IgG collagen I antibodies, which ensured their appropriate orientation onto the sensor’s surface, good stability, and sensitivity properties. The detection of collagen type I was performed in a concentration range from 1 to 5 pg/mL. Moreover, SPR was utilized to confirm the immobilization of the monoclonal half-antibodies and sensing of collagen I versus time. Furthermore, EIS experiments revealed a limit of detection (LOD) of 0.38 pg/mL. The selectivity of the performed immunosensor was confirmed by negligible responses for BSA. The performed approach of the immunosensor is a novel, innovative attempt that enables the detection of collagen I with very high sensitivity in the range of pg/mL, which is significantly lower than the commonly used enzyme-linked immunosorbent assay (ELISA).

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Siverino, Claudia, Shorouk Fahmy-Garcia, Didem Mumcuoglu, Heike Oberwinkler, Markus Muehlemann, Thomas Mueller, Eric Farrell, Gerjo J. V. M. van Osch i Joachim Nickel. "Site-Directed Immobilization of an Engineered Bone Morphogenetic Protein 2 (BMP2) Variant to Collagen-Based Microspheres Induces Bone Formation In Vivo". International Journal of Molecular Sciences 23, nr 7 (1.04.2022): 3928. http://dx.doi.org/10.3390/ijms23073928.

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For the treatment of large bone defects, the commonly used technique of autologous bone grafting presents several drawbacks and limitations. With the discovery of the bone-inducing capabilities of bone morphogenetic protein 2 (BMP2), several delivery techniques were developed and translated to clinical applications. Implantation of scaffolds containing adsorbed BMP2 showed promising results. However, off-label use of this protein-scaffold combination caused severe complications due to an uncontrolled release of the growth factor, which has to be applied in supraphysiological doses in order to induce bone formation. Here, we propose an alternative strategy that focuses on the covalent immobilization of an engineered BMP2 variant to biocompatible scaffolds. The new BMP2 variant harbors an artificial amino acid with a specific functional group, allowing a site-directed covalent scaffold functionalization. The introduced artificial amino acid does not alter BMP2′s bioactivity in vitro. When applied in vivo, the covalently coupled BMP2 variant induces the formation of bone tissue characterized by a structurally different morphology compared to that induced by the same scaffold containing ab-/adsorbed wild-type BMP2. Our results clearly show that this innovative technique comprises translational potential for the development of novel osteoinductive materials, improving safety for patients and reducing costs.

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Hanssen, Eric, Betty Reinboth i Mark A. Gibson. "Covalent and Non-covalent Interactions of βig-h3 with Collagen VI". Journal of Biological Chemistry 278, nr 27 (27.04.2003): 24334–41. http://dx.doi.org/10.1074/jbc.m303455200.

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SEYER, JEROME M., i ANDREW H. KANG. "Covalent Structure of Type V Collagen." Annals of the New York Academy of Sciences 580, nr 1 Structure, Mo (luty 1990): 427–29. http://dx.doi.org/10.1111/j.1749-6632.1990.tb17950.x.

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Leivo, Joni, Sanni Virjula, Sari Vanhatupa, Kimmo Kartasalo, Joose Kreutzer, Susanna Miettinen i Pasi Kallio. "A durable and biocompatible ascorbic acid-based covalent coating method of polydimethylsiloxane for dynamic cell culture". Journal of The Royal Society Interface 14, nr 132 (lipiec 2017): 20170318. http://dx.doi.org/10.1098/rsif.2017.0318.

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Polydimethylsiloxane (PDMS) is widely used in dynamic biological microfluidic applications. As a highly hydrophobic material, native PDMS does not support cell attachment and culture, especially in dynamic conditions. Previous covalent coating methods use glutaraldehyde (GA) which, however, is cytotoxic. This paper introduces a novel and simple method for binding collagen type I covalently on PDMS using ascorbic acid (AA) as a cross-linker instead of GA. We compare the novel method against physisorption and GA cross-linker-based methods. The coatings are characterized by immunostaining, contact angle measurement, atomic force microscopy and infrared spectroscopy, and evaluated in static and stretched human adipose stem cell (hASC) cultures up to 13 days. We found that AA can replace GA as a cross-linker in the covalent coating method and that the coating is durable after sonication and after 6 days of stretching. Furthermore, we show that hASCs attach and proliferate better on AA cross-linked samples compared with physisorbed or GA-based methods. Thus, in this paper, we provide a new PDMS coating method for studying cells, such as hASCs, in static and dynamic conditions. The proposed method is an important step in the development of PDMS-based devices in cell and tissue engineering applications.

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Pence, Jacquelyn C., Emily A. Gonnerman, Ryan C. Bailey i Brendan A. C. Harley. "Strategies to balance covalent and non-covalent biomolecule attachment within collagen-GAG biomaterials". Biomater. Sci. 2, nr 9 (2014): 1296–304. http://dx.doi.org/10.1039/c4bm00193a.

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Incorporating selective biomolecular cues within a biomaterial requires balancing covalent attachment versus non-specific fouling. We use a model collagen-GAG scaffold to define the impact of processing conditions on immobilization versus fouling.

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Chen, Qian, John M. Fitch, Cathy Linsenmayer i Thomas F. Linsenmayer. "Type X collagen: covalent crosslinking to hypertrophic cartilage-collagen fibrils". Bone and Mineral 17, nr 2 (maj 1992): 223–27. http://dx.doi.org/10.1016/0169-6009(92)90741-u.

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Li, I.-Che, Sarah A. H. Hulgan, Douglas R. Walker, Richard W. Farndale, Jeffrey D. Hartgerink i Abhishek A. Jalan. "Covalent Capture of a Heterotrimeric Collagen Helix". Organic Letters 21, nr 14 (27.06.2019): 5480–84. http://dx.doi.org/10.1021/acs.orglett.9b01771.

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SCHUPPAN, Detlef, Robert W. GLANVILLE i Rupert TIMPL. "Covalent Structure of Mouse Type-IV Collagen". European Journal of Biochemistry 123, nr 3 (3.03.2005): 505–12. http://dx.doi.org/10.1111/j.1432-1033.1982.tb06560.x.

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Bisconte, Angelina, Ronald Hill, Michael Bradshaw, Erik Verner, David Finkle, Ken Brameld, Jens Funk, David Goldstein i Phil Nunn. "Efficacy in collagen induced arthritis models with a selective, reversible covalent Bruton’s tyrosine kinase inhibitor PRN473 is driven by durable target occupancy rather than extended plasma exposure (THER5P.904)". Journal of Immunology 194, nr 1_Supplement (1.05.2015): 139.6. http://dx.doi.org/10.4049/jimmunol.194.supp.139.6.

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Abstract Bruton’s Tyrosine Kinase (BTK) is an essential signaling element downstream of the B-cell receptor (BCR). Inhibition of BTK activity in B cells produces phenotypic changes consistent with blockade of the BCR, including inhibition of cell proliferation, differentiation, maturation, and survival. A selective BTK inhibitor has the potential to treat diseases involving inflammation and autoimmunity. Using Principia Biopharma’s proprietary Tailored Covalency™ technology, we discovered PRN473, a reversible covalent BTK inhibitor that selectively binds BTK with a slow off-rate as assessed in biochemical and cell based assays. A slow off-rate molecule with rapid systemic clearance may lead to a long duration of action and high efficacy, while reducing the potential for off target toxicities. The duration of binding of PRN473 was measured in vivo, with prolonged BTK occupancy confirmed after drug was cleared from plasma. In mouse and rat collagen-induced arthritis (CIA) models, PRN473 when dosed therapeutically demonstrated dose-dependent inhibition, reversal of arthritis, with almost complete abrogation of clinical scores and preservation of joint integrity and histology. BTK occupancy in splenocytes was found to be a robust measure of BTK inhibition and correlated with efficacy in the CIA models. These data in combination with GLP toxicology studies, where no organ specific toxicities were observed, validate using a reversible covalent BTK inhibitor to treat autoimmune diseases.

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Mays, P. K., R. J. McAnulty, J. S. Campa i G. J. Laurent. "Age-related changes in collagen synthesis and degradation in rat tissues. Importance of degradation of newly synthesized collagen in regulating collagen production". Biochemical Journal 276, nr 2 (1.06.1991): 307–13. http://dx.doi.org/10.1042/bj2760307.

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During developmental growth, collagens are believed to be continuously deposited into an extracellular matrix which is increasingly stabilized by the formation of covalent cross-links throughout life. However, the age-related changes in rates of synthetic and degradative processes are less well understood. In the present study we measured rates of collagen synthesis in vivo using a flooding dose of unlabelled proline given with [14C]proline and determining production of hydroxy[14C]proline. Degradation of newly synthesized collagen was estimated from the amount of free hydroxy [14C]proline in tissues 30 min after injection. Collagen fractional synthesis rates ranged from about 5%/day in skeletal muscle to 20%/day in hearts of rats aged 1 month. At 15 months of age, collagen fractional synthesis rates had decreased markedly in lung and skin, but in skeletal muscle and heart, rates were unchanged. At 24 months of age, synthesis rates had decreased by at least 10-fold in all tissues, compared with rates at 1 month. The proportion of newly synthesized collagen degraded ranged from 6.4 +/- 0.4% in skin to 61.6 +/- 5.0% in heart at 1 month of age. During aging the proportion degraded increased in all tissues to maximal values at 15 months, ranging from 56 +/- 7% in skin to 96 +/- 1% in heart. These data suggest that there are marked age-related changes in rates of collagen metabolism. They also indicate that synthesis is active even in old animals, where the bulk of collagens produced are destined to be degraded.

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Ruben, George C., i Peter D. Yurchenco. "Evidence for lateral associations in the Type IV collagen network from freeze-dried platinum-carbon replicated amniotic basement membrane". Proceedings, annual meeting, Electron Microscopy Society of America 45 (sierpień 1987): 968–69. http://dx.doi.org/10.1017/s0424820100129127.

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The structural scaffolding of basement membrane (BM) is formed by a polymerized and covalently cross-linked network of type IV collagen whose molecular structure in situ has eluded detailed analysis. The monomeric unit of assembly of this collagen is a 424nm linear protein which, compared to other interstitial collagens, is longer, more flexible, contains frequent interruptions by non-collagenous type sequences, and possesses distinct end-region domains. Type IV collagen, unlike the interstitial collagens I, II & III, does not assemble into long bundled fibers. Our present knowledge of collagen IV's intermole- cular associations comes from biochemical characterizations correlated with low angle rotary shadowed glycerol spreads of proteolytically extracted fragments’ and reconstituted collagen IV oligomeric complexes and networks Earlier work led to the identification of an amino(N)-terminal 30nm region that binds three other N-termini in an overlapping fashion to produce a four-armed tetramer (7s domain) and a carboxyl(C)-terminal globular domain (NC-1) of a given monomer which attaches to the same domain of another monomer to form a linear dimer.

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Ayad, S., A. Marriott, K. Morgan i M. E. Grant. "Bovine cartilage types VI and IX collagens. Characterization of their forms in vivo". Biochemical Journal 262, nr 3 (15.09.1989): 753–61. http://dx.doi.org/10.1042/bj2620753.

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1. Collagens were extracted from bovine cartilage by 4 M-guanidinium chloride in the presence of proteinase inhibitors and identified by immunoblotting with specific anti-collagen sera. 2. The collagens retained their native conformations (shown by the resistance of their triple-helical domains to pepsin digestion), and the molecular masses of their component alpha-chains indicated that the chains were intact. 3. Type VI collagen was extracted as a large-molecular-mass disulphide-bonded aggregate composed of components of molecular mass 140 kDa and 200-240 kDa, and was therefore similar to type VI collagen identified in noncartilaginous tissues. Immunoblotting established the 200-240 kDa components as intact forms of the alpha 3(VI) chain. 4. Type IX collagen consisted of three clearly separable components of molecular mass 84 kDa, 72 kDa and 66 kDa, which were assigned to the alpha 1(IX)-, alpha 3(IX)- and alpha 2(IX)-chains respectively, and a large proportion of this collagen had no covalently bound glycosaminoglycan attached to the alpha 2(IX)-chain. 5. Differences between the type IX collagen extracted from bovine cartilage and that identified in biosynthetic studies on chick cartilage are discussed.

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He, Yingcong, Ting Zhu, Lei Liu, Xuetao Shi i Zhengmei Lin. "Modifying collagen with alendronate sodium for bone regeneration applications". RSC Advances 8, nr 30 (2018): 16762–72. http://dx.doi.org/10.1039/c8ra01872c.

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Zhang, Tingting, Hong Chen, Yajie Zhang, Yue Zan, Tianyu Ni, Min Liu i Renjun Pei. "Osteogenic differentiation of BMSCs in collagen-based 3D scaffolds". New Journal of Chemistry 43, nr 4 (2019): 1980–86. http://dx.doi.org/10.1039/c8nj04100h.

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Jiang, Bo, Zhi Hong Wu, Jing Ying Zeng, Jian Lu, Qing Rong Wei, Xing Dong Zhang i Zhong Wei Gu. "Collagenous Molecule Immobilization on Hydroxyapatite Surface". Key Engineering Materials 330-332 (luty 2007): 741–44. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.741.

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Collagenous molecule was successfully immobilized to hydroxyapatite (HA) surface through a molecular bridge (2-Hydroxyethyl acrylate, HEMA) that was grafted to the surface with covalent bond by gamma irradiation. Hydroxyapatite modified by atelocollagen had been characterized by several surface sensitive techniques, such as FT-IR, SEM, XPS. The investigations showed that the collagen, a bioactive macromolecule, was immobilized on the HA surface through covalent bond.

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Wu, Jiann-Jiu, i David R. Eyre. "Covalent Interactions of Type IX Collagen in Cartilage". Connective Tissue Research 20, nr 1-4 (styczeń 1989): 241–45. http://dx.doi.org/10.3109/03008208909023893.

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Velichko, T. I., A. N. Shtopenko, N. V. Fedoseeva i G. S. Katrukha. "Covalent immobilization of heparin on a collagen film". Chemistry of Natural Compounds 23, nr 5 (wrzesień 1987): 582–85. http://dx.doi.org/10.1007/bf00598679.

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Jukkola, Arja, i Onni Niemelä. "Covalent binding of acetaldehyde to type III collagen". Biochemical and Biophysical Research Communications 159, nr 1 (luty 1989): 163–69. http://dx.doi.org/10.1016/0006-291x(89)92418-2.

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Priem, Christoph, i Armin Geyer. "Reversible Covalent End‐Capping of Collagen Model Peptides". Chemistry – A European Journal 25, nr 63 (17.10.2019): 14278–83. http://dx.doi.org/10.1002/chem.201903460.

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Liang, He, Stephen J. Russell, David J. Wood i Giuseppe Tronci. "A hydroxamic acid–methacrylated collagen conjugate for the modulation of inflammation-related MMP upregulation". Journal of Materials Chemistry B 6, nr 22 (2018): 3703–15. http://dx.doi.org/10.1039/c7tb03035e.

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Yamauchi, Mitsuo, i Marnisa Sricholpech. "Lysine post-translational modifications of collagen". Essays in Biochemistry 52 (25.05.2012): 113–33. http://dx.doi.org/10.1042/bse0520113.

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Type I collagen is the most abundant structural protein in vertebrates. It is a heterotrimeric molecule composed of two α1 chains and one α2 chain, forming a long uninterrupted triple helical structure with short non-triple helical telopeptides at both the N- and C-termini. During biosynthesis, collagen acquires a number of post-translational modifications, including lysine modifications, that are critical to the structure and biological functions of this protein. Lysine modifications of collagen are highly complicated sequential processes catalysed by several groups of enzymes leading to the final step of biosynthesis, covalent intermolecular cross-linking. In the cell, specific lysine residues are hydroxylated to form hydroxylysine. Then specific hydroxylysine residues located in the helical domain of the molecule are glycosylated by the addition of galactose or glucose-galactose. Outside the cell, lysine and hydroxylysine residues in the N- and C-telopeptides can be oxidatively deaminated to produce reactive aldehydes that undergo a series of non-enzymatic condensation reactions to form covalent intra- and inter-molecular cross-links. Owing to the recent advances in molecular and cellular biology, and analytical technologies, the biological significance and molecular mechanisms of these modifications have been gradually elucidated. This chapter provides an overview on these enzymatic lysine modifications and subsequent cross-linking.

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Brooker, Charles, i Giuseppe Tronci. "Effect of Mammalian Tissue Source on the Molecular and Macroscopic Characteristics of UV-Cured Type I Collagen Hydrogel Networks". Prosthesis 4, nr 1 (21.01.2022): 1–14. http://dx.doi.org/10.3390/prosthesis4010001.

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The tissue source of type I collagen is critical to ensure scalability and regulation-friendly clinical translation of new medical device prototypes. However, the selection of a commercial source of collagen that fulfils both aforementioned requirements and is compliant with new manufacturing routes is challenging. This study investigates the effect that type I collagen extracted from three different mammalian tissues has on the molecular and macroscopic characteristics of a new UV-cured collagen hydrogel. Pepsin-solubilised bovine atelocollagen (BA) and pepsin-solubilised porcine atelocollagen (PA) were selected as commercially available raw materials associated with varying safety risks and compared with in-house acid-extracted type I collagen from rat tails (CRT). All raw materials displayed the typical dichroic and electrophoretic characteristics of type I collagen, while significantly decreased lysine content was measured on samples of PA. Following covalent functionalisation with 4-vinylbenzyl chloride (4VBC), BA and CRT products generated comparable UV-cured hydrogels with significantly increased averaged gel content (G ≥ 97 wt.%), while the porcine variants revealed the highest swelling ratio (SR = 2224 ± 242 wt.%) and an order of magnitude reduction in compression modulus (Ec = 6 ± 2 kPa). Collectively, these results support the use of bovine tissues as a chemically viable source of type I collagen for the realisation of UV-cured hydrogels with competitive mechanical properties and covalent network architectures.

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Eyre, David R., Stephen Apon, Jiann-Jiu Wu, Lowell H. Ericsson i Kenneth A. Walsh. "Collagen type IX: Evidence for covalent linkages to type II collagen in cartilage". FEBS Letters 220, nr 2 (17.08.1987): 337–41. http://dx.doi.org/10.1016/0014-5793(87)80842-6.

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Añazco, Carolina, Janin Riedelsberger, Lorenzo Vega-Montoto i Armando Rojas. "Exploring the Interplay between Polyphenols and Lysyl Oxidase Enzymes for Maintaining Extracellular Matrix Homeostasis". International Journal of Molecular Sciences 24, nr 13 (1.07.2023): 10985. http://dx.doi.org/10.3390/ijms241310985.

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Collagen, the most abundant structural protein found in mammals, plays a vital role as a constituent of the extracellular matrix (ECM) that surrounds cells. Collagen fibrils are strengthened through the formation of covalent cross-links, which involve complex enzymatic and non-enzymatic reactions. Lysyl oxidase (LOX) is responsible for catalyzing the oxidative deamination of lysine and hydroxylysine residues, resulting in the production of aldehydes, allysine, and hydroxyallysine. These intermediates undergo spontaneous condensation reactions, leading to the formation of immature cross-links, which are the initial step in the development of mature covalent cross-links. Additionally, non-enzymatic glycation contributes to the formation of abnormal cross-linking in collagen fibrils. During glycation, specific lysine and arginine residues in collagen are modified by reducing sugars, leading to the creation of Advanced Glycation End-products (AGEs). These AGEs have been associated with changes in the mechanical properties of collagen fibers. Interestingly, various studies have reported that plant polyphenols possess amine oxidase-like activity and can act as potent inhibitors of protein glycation. This review article focuses on compiling the literature describing polyphenols with amine oxidase-like activity and antiglycation properties. Specifically, we explore the molecular mechanisms by which specific flavonoids impact or protect the normal collagen cross-linking process. Furthermore, we discuss how these dual activities can be harnessed to generate properly cross-linked collagen molecules, thereby promoting the stabilization of highly organized collagen fibrils.

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Yu, Le Tracy, i Jeffrey D. Hartgerink. "Selective covalent capture of collagen triple helices with a minimal protecting group strategy". Chemical Science 13, nr 9 (2022): 2789–96. http://dx.doi.org/10.1039/d1sc06361h.

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A minimal protecting group strategy is developed to allow selective covalent capture of collagen-like triple helices. This allows stabilization of this critical fold while preserving charge–pair interactions critical for biological applications.

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Hilderbrand, Amber M., Eden M. Ford, Chen Guo, Jennifer D. Sloppy i April M. Kloxin. "Hierarchically structured hydrogels utilizing multifunctional assembling peptides for 3D cell culture". Biomaterials Science 8, nr 5 (2020): 1256–69. http://dx.doi.org/10.1039/c9bm01894h.

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Synthetic multifunctional assembling peptides were designed to mimic the structure of collagen and allow independent control of hydrogel mechanical and biochemical properties through covalent crosslinking, enabling long-term in vitro 3D cell culture.

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BARBER, Ruth E., i Alvin P. L. KWAN. "Partial characterization of the C-terminal non-collagenous domain (NC1) of collagen type X". Biochemical Journal 320, nr 2 (1.12.1996): 479–85. http://dx.doi.org/10.1042/bj3200479.

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Collagen type X is composed of three identical α1(X) chains of 59 kDa, each containing a triple-helical region of 45 kDa flanked by a short N-terminal sequence and a larger non-collagenous C-terminal (NC1) domain of approx. 15 kDa. Collagen type X molecules can associate via their C-termini to form a regular hexagonal lattice in vitro, which in vivo may provide a modified extracellular matrix for the events of endochondral ossification. The NC1 domain of chick collagen type X was isolated and purified from a highly purified bacterial collagenase digest of hypertrophic chondrocyte medium proteins. The structure and aggregation properties of the NC1 domain of collagen X were investigated, independently of the triple helix. A trimer, a dimer and a monomer of the individual α-chain NC1 polypeptides were identified from a bacterial collagenase digest of cartilage collagens using [14C]tyrosine labelling, N-chlorosuccinimide peptide mapping and N-terminal sequencing. The trimer (50 kDa) remained intact in Laemmli sample buffer unless boiled, upon which it dissociated into the dimer (38 kDa) and the monomer (20 kDa). The dimer persisted even after prolonged periods of heating or reduction with β-mercaptoethanol, and in preparations obtained from chondrocyte cultures treated with β-aminoproprionitrile, indicating the presence of non-reducible, non-lysine-derived, covalent cross-links. Hexamers of the individual C-termini were observed in rotary-shadowed preparations of purified NC1 domain, reflecting the ability of collagen type X to self-assemble via its C-termini under appropriate conditions.

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Vadlamudi, R. K., R. J. McCormick, D. M. Medeiros, J. Vossoughi i M. L. Failla. "Copper deficiency alters collagen types and covalent cross-linking in swine myocardium and cardiac valves". American Journal of Physiology-Heart and Circulatory Physiology 264, nr 6 (1.06.1993): H2154—H2161. http://dx.doi.org/10.1152/ajpheart.1993.264.6.h2154.

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Dietary copper deficiency induces alterations of connective tissue metabolism that are associated with lesions in cardiovascular and other organ systems. To determine the impact of copper deficiency on characteristics of collagen in porcine myocardium and cardiac valves, weaned pigs were fed diets with adequate or deficient levels of copper. Although dietary copper did not affect the concentration of collagen in either myocardium or bicuspid valves, the degree of collagen cross-linking, as assessed by the level of hydroxylysylpyridinoline, was lower in both tissues of copper-deficient pigs. Proportions of type III collagen were increased in the left ventricle and bicuspid valves of copper-deficient pigs. Copper deficiency induced extensive remodeling, however, of the collagen fraction of cardiac interstitium. Reduction in left ventricular collagen cross-linking may provide the stimulus for the development of cardiac hypertrophy, which characterizes severe copper deficiency, by increasing the compliance of the ventricular wall. The shift in the phenotypic profile of collagen that is associated with this cardiac hypertrophy indicates synthesis of new collagen, which could affect collagen cross-linking irrespective of copper status.

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González-Paz, Rodolfo J., Ana M. Ferreira, Clara Mattu, Francesca Boccafoschi, Gerard Lligadas, Juan C. Ronda, Marina Galià, Virginia Cádiz i Gianluca Ciardelli. "Cytocompatible polyurethanes from fatty acids through covalent immobilization of collagen". Reactive and Functional Polymers 73, nr 5 (maj 2013): 690–97. http://dx.doi.org/10.1016/j.reactfunctpolym.2013.02.005.

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Koch, S., Ch Yao, G. Grieb, P. Prével, E. M. Noah i G. C. M. Steffens. "Enhancing angiogenesis in collagen matrices by covalent incorporation of VEGF". Journal of Materials Science: Materials in Medicine 17, nr 8 (sierpień 2006): 735–41. http://dx.doi.org/10.1007/s10856-006-9684-x.

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Keuren, Jeffrey F. W., Simone J. H. Wielders, Anita Driessen, Michel Verhoeven, Marc Hendriks i Theo Lindhout. "Covalently-Bound Heparin Makes Collagen Thromboresistant". Arteriosclerosis, Thrombosis, and Vascular Biology 24, nr 3 (marzec 2004): 613–17. http://dx.doi.org/10.1161/01.atv.0000116026.18945.66.

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Crawford, S. W., R. P. Mecham i H. Sage. "Structural characteristics and intermolecular organization of human pulmonary-surfactant-associated proteins". Biochemical Journal 240, nr 1 (15.11.1986): 107–14. http://dx.doi.org/10.1042/bj2400107.

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The structural relationships and intermolecular organization among the proteins associated with pulmonary surfactant are largely unknown. We studied the pulmonary-surfactant-associated proteins in the bronchoalveolar lavage fluid obtained from a patient with the clinical syndrome of alveolar proteinosis. The major proteins with Mr values of 32,000-36,000 and 62,000 formed thiol-dependent complexes (Mr greater than 400,000) with intermolecular disulphide bonds present in the collgenase-sensitive domains of these proteins. In contrast, other proteins, which were collagenase-insensitive, formed thiol-dependent oligomers that were not covalently linked to the major proteins. The associations of these proteins in the surfactant of a normal individual were similar. By amino acid analysis, two-dimensional peptide mapping and bacterial-collagenase digestion the 32,000-36,000-Mr and 62,000-Mr proteins were nearly identical. Differences in CNBr cleavage products suggested that the larger of the proteins was formed by non-disulphide, covalent, cross-links in the collagenase-sensitive domains of the 32,000-36,000-Mr proteins. Thus the evidence suggested that the lipid-associated proteins of Mr 32,000-36, 000 contained both disulphide and non-disulphide cross-links in the collagen-like N-terminal region of the proteins and form higher-Mr complexes. This organization may support the three-dimensional conformation of surfactant in the alveolar space.

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42

Sabeh, Farideh, Ryoko Shimizu-Hirota i Stephen J. Weiss. "Protease-dependent versus -independent cancer cell invasion programs: three-dimensional amoeboid movement revisited". Journal of Cell Biology 185, nr 1 (30.03.2009): 11–19. http://dx.doi.org/10.1083/jcb.200807195.

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Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.

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Wieczorek, Andrew, Clara K. Chan, Suzana Kovacic, Cindy Li, Thomas Dierks i Nancy R. Forde. "Genetically modified human type II collagen for N- and C-terminal covalent tagging". Canadian Journal of Chemistry 96, nr 2 (luty 2018): 204–11. http://dx.doi.org/10.1139/cjc-2017-0335.

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Collagen is the predominant structural protein in vertebrates, where it contributes to connective tissues and the ECM; it is also widely used in biomaterials and tissue engineering. Dysfunction of this protein and its processing can lead to a wide variety of developmental disorders and connective tissue diseases. Recombinantly engineering the protein is challenging due to post-translational modifications generally required for its stability and secretion from cells. Introducing end labels into the protein is problematic, because the N- and C-termini of the physiologically relevant tropocollagen lie internal to the initially flanking N- and C-propeptide sequences. Here, we introduce mutations into human type II procollagen in a manner that addresses these concerns and purify the recombinant protein from a stably transfected HT1080 human fibrosarcoma cell line. Our approach introduces chemically addressable groups into the N- and C-telopeptide termini of tropocollagen. Simultaneous overexpression of formylglycine generating enzyme (FGE) allows the endogenous production of an aldehyde tag in a defined, substituted sequence in the N terminus of the mutated collagen, whereas the C-terminus of each chain presents a sulfhydryl group from an introduced cysteine. These modifications are designed to enable specific covalent end-labelling of collagen. We find that the doubly mutated protein folds and is secreted from cells. Higher order assembly into well-ordered collagen fibrils is demonstrated through transmission electron microscopy. Chemical tagging of thiols is successful; however, background from endogenous aldehydes present in wild-type collagen has thus far obscured the desired specific N-terminal labelling. Strategies to overcome this challenge are proposed.

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Han, Ying, Jiaxun Li, Bobing He i Lixin Li. "Preparation and characterization of a novel ACF-TpPa-1 composite for dye adsorption". Journal of Engineered Fibers and Fabrics 16 (styczeń 2021): 155892502110158. http://dx.doi.org/10.1177/15589250211015898.

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Environmental challenges, especially dye wastewater produced by printing and dyeing industry, pose a serious threat to global public health, and it is an urgent problem to realize harmless treatment of dye wastewater. Here, the combination of covalent organic framework materials (TpPa-1) and biological matrix materials (CF) was explored for the adsorption of dyes for the first time. The functional ACF-TpPa-1 composite adsorption materials were successfully prepared with collagen fiber (CF) made of leather waste as matrix, ethylenediamine (EDA) and covalent organic framework material (TpPa-1) as modified raw materials. It’s structure and properties were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM). The experimental results showed that ACF-TpPa-1 had an adsorption capacity of 257.98 and 449.54 mg/g for acid fuchsia and reactive blue 19, respectively. It also showed excellent adsorption/desorption performance and repeatability after six cycles. As a collagen-based dye adsorbent with pH response, it has potential application prospects in the treatment of dye wastewater.

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Li, Baoe, Xuan Yong Liu i Chuan Xian Ding. "Grafting Collagen on the Plasma Sprayed Titania Coating Treated by Sodium Hydroxide". Key Engineering Materials 330-332 (luty 2007): 541–44. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.541.

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In this work, collagen type I was covalently grafted on the surface of plasma sprayed titania coatings to improve their biocompatibility. The plasma sprayed titania coatings were pretreated by sodium hydroxide to induce the formation of hydroxyl groups which can covalently graft collagen, rendering the collagen having good stability. The dependence of collagen grafting on the sodium hydroxide treatment conditions (concentration, time and temperature) was investigated by measuring the amount of collagen grafted on the titania surface. The biocompatibility of the titania coatings with grafted collagen was evaluated by in vitro cell culture. The results showed that the amount of collagen grafted on the titania coatings increased with the concentration of the sodium hydroxide and the treating temperature, while that on the coating is slightly dependent on the treatment time in sodium hydroxide. In vitro cell culture test proved the positive effects of collagen on the biocompatibility of the plasma sprayed titania coating.

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Constantinescu, Mihai A., Alex Alfieri, George Mihalache, Florian Stuker, Angélique Ducray, Rolf W. Seiler, Martin Frenz i Michael Reinert. "Effect of laser soldering irradiation on covalent bonds of pure collagen". Lasers in Medical Science 22, nr 1 (7.11.2006): 10–14. http://dx.doi.org/10.1007/s10103-006-0411-0.

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Bornstein, Paul. "Covalent cross-links in collagen: a personal account of their discovery". Matrix Biology 22, nr 5 (wrzesień 2003): 385–91. http://dx.doi.org/10.1016/s0945-053x(03)00061-1.

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Choi, Sharon H., Rebecca L. Davis-Harrison, Stephanie A. Smith, Julie N. R. Collins, Chad M. Rienstra i James H. Morrissey. "Covalent End-Labeling of Polyphosphate Facilitates Studies of Its Procoagulant Activities and Development of Enhanced Agents to Treat Bleeding." Blood 116, nr 21 (19.11.2010): 1138. http://dx.doi.org/10.1182/blood.v116.21.1138.1138.

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Abstract Abstract 1138 Introduction: Inorganic polyphosphates (polyP) are negatively charged, linear phosphate polymers that are abundant in platelet dense granules and secreted upon platelet activation. We recently reported that polyP may be the long-sought (patho)physiologic activator of the contact pathway with important roles in inflammation and thrombosis. We also reported that polyP opposes the action of many anticoagulant drugs and thus has potential as a general procoagulant agent to treat bleeding. Studies of the role of polyP in blood clotting would be facilitated by being able to covalently attach probes – including fluorophores and biotin – to the ends of polyP. For therapeutic applications, it would also be advantageous to covalently immobilize polyP onto solid supports like collagen sponges and wound dressings. We now report that a wide variety of primary amine-containing compounds can be covalently attached to the terminal phosphates of polyP via phosphoramidate linkages. This allows essentially the full armamentarium of protein chemistry to be employed in modifying polyP. Methods: We have developed and optimized reaction conditions under which EDAC (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide) efficiently promotes the covalent coupling of compounds with primary amines to polyP via the formation of stable phosphoramidate linkages with the terminal phosphate groups (see figure). Results & Conclusions: Using 31P NMR, we have confirmed that EDAC-mediated reaction between primary amines and polyP results in stable phosphoramidate linkages with the terminal phosphate groups. We have used this chemistry to efficiently float polyP onto amine-derivatized microtiter plates and chromatography beads, and have used this presentation of polyP to quantify the binding affinities of thrombin, kallikrein, and factor XIa for polyP. We have also successfully attached fluorescent probes to the termini of polyP and thereby visualized the incorporation of polyP into fibrin clots. We have also demonstrated that polyP covalently attached to solid supports via phosphoramidate linkages retains potent procoagulant activity. And finally, we have found that attaching small organic molecules to the terminal phosphates of polyP protects polyP from degradation by exopolyphosphatases such as alkaline phosphatase, which should prolong its in vivo half-life considerably. These findings facilitate more extensive studies of the biological role(s) of polyP, as well as development of enhanced polyP-based treatments for bleeding. Disclosures: Smith: University of Illinois: Patents & Royalties. Morrissey:University of Illinois: Patents & Royalties.

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Kent, M. J. C., N. D. Light i A. J. Bailey. "Evidence for glucose-mediated covalent cross-linking of collagen after glycosylation in vitro". Biochemical Journal 225, nr 3 (1.02.1985): 745–52. http://dx.doi.org/10.1042/bj2250745.

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Rabbit forelimb tendons incubated for 15 or 21 days at 35 degrees C in the presence of 8 or 24 mg of glucose/ml were shown to change their chemical, biochemical and mechanical characteristics. The tendons treated with glucose contained up to three times as much hexosyl-lysine and hexosylhydroxylysine as did control tendons as judged by assay of NaB3H4-reduced samples. Measurement of the force generated on thermal contraction showed significant increases in glycosylated tendons compared with controls, indicating the formation of new covalent stabilizing bonds. This conclusion was supported by the decreased solubility of intact tendons and re-formed fibres glycosylated in vitro, and by the evidence from peptide maps of CNBr-digested glucose-incubated tendons. The latter, when compared with peptide maps of control tendons, revealed the presence of additional high-Mr peptide material. These peptides appear to be cross-linked by a new type of covalent bond stable to mild thermal and chemical treatment. This system in vitro provides a readily controlled model for the study of the chemistry of changes brought about in collagen by non-enzymic glycosylation in diabetes.

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Agubata, Chukwuma O., Cynthia C. Mbaoji, Ifeanyi T. Nzekwe, César Saldías i David Díaz Díaz. "Biohydrogel Based on Dynamic Covalent Bonds for Wound Healing Applications". Applied Sciences 11, nr 15 (28.07.2021): 6945. http://dx.doi.org/10.3390/app11156945.

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In this work, a biohydrogel based on alginate and dynamic covalent B-O bonds, and derived composites, has been evaluated for wound healing applications. In particular, a phenylboronic acid–alginate (PBA-Alg) complex was synthesized by coupling 3-aminophenylboronic acid onto alginate, and used to prepare varied concentrations of hydrogels and silicate-based nanocomposites in PBS. The resulting hydrogels were characterized in terms of interfacial tension, moisture uptake and loss, interaction with fresh acid-soluble collagen, self-healing ability, effects on blood clotting and wound healing. The interfacial tension between the hydrogels and biorelevant fluids was low and moisture loss of 55–60% was evident without uptake from the environment. The components of the hydrogels and their mixtures with collagen were found to be compatible. These hydrogels showed efficient self-healing and thixotropic behavior, and the animals in the treatment groups displayed blood clotting times between 9.1 min and 10.7 min. In contrast, the composites showed much longer or shorter clotting times depending on the silicate content. A significant improvement in wound healing was observed in 3% w/v PBA-Alg formulations. Overall, the PBA-Alg hydrogels exhibit self-healing dynamic covalent interactions and may be useful in dressings for incision wounds.

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