Дисертації з теми "Force spectroscopy- biological application"
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Shang, Guangyi. "Development of a shear force scanning near-field optical microscope for biological applications: imaging ans spectroscopy." Reims, 2004. http://www.theses.fr/2004REIMS005.
Повний текст джерелаBased on a new force sensor, a shear force scanning near-field optical microscope (ShF-SNOM), that can be operated in the different modes and combined with a confocal laser microspectrofluorometer (CLMF) for biological applications, has been developed. Shear force mechanism was experimentally studied and the knocking mechanism is the main origin responsible for shear force distance control in our system. Experimental parameters concerning the shear force imaging and artifacts due to probe geometric effects are discussed. Shear force and near-field imaging of a silicon grating in the reflection mode, imaging and spectroscopy of electroluminescent structures in the collection mode are demonstrated respectively. As a preliminary study for biological applications, the distribution of P-glycoprotein (P-gp) in the plasma membrane of human small cell lung cancer cells were investigated with sub-diffraction limit resolution. The distribution of P-gp in the cell membrane was found to be not homogenous and cluster formation of P-gp in the membrane was observed. In addition, fluorescence spectra were recorded in a single living cell of human breast adenocarcinoma cells stained with the fluorescent dye JC-1. The variations in fluorescence spectra were measured with vertical resolution of about 100 nm. These results suggest that our system would be a promising tool for biological applications and provide valuable information for understanding some biological problems
Graham, John Stephen. "Mechanical properties of complex biological systems using AFM-based force spectroscopy." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4191.
Повний текст джерелаThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 18, 2007) Vita. Includes bibliographical references.
Klamecka, Kamila [Verfasser], and Heinrich [Akademischer Betreuer] Leonhardt. "Single-molecule force spectroscopy of biological complexes / Kamila Klamecka ; Betreuer: Heinrich Leonhardt." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1156851874/34.
Повний текст джерелаOtt, Wolfgang Bernhard [Verfasser], and Hermann [Akademischer Betreuer] Gaub. "Single molecule force spectroscopy with biological tools / Wolfgang Bernhard Ott ; Betreuer: Hermann Gaub." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1175878677/34.
Повний текст джерелаFerrer, Jorge M. 1976. "Mapping the actin and actin binding proteins interactions : from micromechanics to single molecule force spectroscopy." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40950.
Повний текст джерелаIncludes bibliographical references.
Mechanical forces play an important role in cell morphology, orientation, migration, adhesion and can even induce apoptosis. The eukaryotic cell is equipped with a dynamic frame, known as the cytoskeleton, that provides the cell's structural integrity in order to sustain and react to such forces. Therefore, understanding the mechanical properties of the cytoskeleton is an important step towards building models describing cell behavior. Filamentous actin (F-actin), as one of the major constituents of the cytoskeleton, has been the target of extensive in vitro studies to determine its mechanical properties in bulk. However, there is still a lack in the understanding of how the molecular interactions between F-actin and the proteins that arrange these filaments into networks regulate the dynamic properties of the cytoskeleton Here we present a novel, single molecule assay to test the rupture force of a complex formed by an actin binding protein (ABP) linking two actin filaments. We readily demonstrate the adaptability of this assay by testing it with two different ABPs: filamin, a crosslinker, and a-actinin, a bundler. We measured rupture forces of 28-73 pN and 30-56 pN for filamin/actin and a-actinin/actin respectively, suggesting that the former is a slightly stronger interaction. Moreover, since no ABP unfolding events were observed at our force levels, our results suggest that ABP unbinding is a more relevant mechanism than unfolding for the temporal regulation of the mechanical properties of the actin cytoskeleton. In addition, we explore the micro-scale properties of F-actin networks reconstituted in vitro.
(cont.) Using imaging and microrheology techniques we characterized the effects of filament length and degree of crosslinking on the structural arrangement and mechanical properties of F-actin networks. We found that the mechanical properties of these networks are length-scale dependent. Also, when probed with active methods, the F-actin networks exhibited strain hardening followed by a gradual softening at forces -30 pN, in good agreement with the single molecule rupture force of 28-73 pN. Thus, with the combination of single molecule and network studies, we can expand the knowledge-base on the regulation and control of the cellular machinery starting from the molecular building blocks.
by Jorge M. Ferrer.
Ph.D.
Byrne, Katherine. "The viscoelastic response of single biological molecules to thermal noise by atomic force spectroscopy." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432315.
Повний текст джерелаMa, Yong. "THz time domain spectroscopy and its application in biological sciences." Thesis, University of Essex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496274.
Повний текст джерелаYoung, Seth Lawton. "Atomic force microscopy probing methods for soft viscoelastic synthetic and biological materials and structures." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54982.
Повний текст джерелаStone, Nicholas. "Raman spectroscopy of biological tissue for application in optical diagnosis of malignancy." Thesis, Cranfield University, 2001. http://dspace.lib.cranfield.ac.uk/handle/1826/4015.
Повний текст джерелаD'Entremont, Matthew Ivan. "The application of impedance spectroscopy to assess the viability of biological tissue." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0031/MQ63499.pdf.
Повний текст джерелаStone, N. "Raman spectroscopy of biological tissue for application in optical diagnosis of malignancy." Thesis, Department of Environmental and Ordnance Systems, 2009. http://hdl.handle.net/1826/4015.
Повний текст джерелаBippes, Christian Alexander. "Investigation of biological macromolecules using atomic force microscope-based techniques." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-23734.
Повний текст джерелаSarinas, Simon. "Application of Fourier Transform Raman Spectroscopy to the characterisation of significant biological materials." Thesis, Queensland University of Technology, 1994. https://eprints.qut.edu.au/37167/1/37167_Sarinas_1994.pdf.
Повний текст джерелаTakahashi, Hirohide. "Force measurement and mapping of biological macromolecules using atomic force microscopy :Development and application of AFM probe modification procedure." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142450.
Повний текст джерелаReiter-Scherer, Valentin D. "Multivalency in the interaction of biological polymers." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21711.
Повний текст джерелаThis thesis focuses on studying multivalent interactions between influenza virus hemagglutinin (HA) as well as neuraminidase (NA) of two viral strains (H1N1 and H3N2) and the cellular ligand sialic acid (SA) by using scanning force microscopy and single molecule force spectroscopy (SMFS). Unbinding forces as well as dissociation and association kinetics together with the free energy landscapes were, to the best knowledge for the first time, individually quantified on the single molecule level using SMFS. To this extent, designed synthetic monovalent (SAPEGLA) and multivalent (dPGSA) SA displaying ligands were employed. Surprisingly, the experimental force spectra did not show the log-linear trend predicted by the classical Kramers-Bell-Evans model, but rather follow the more recent Friddle-Noy-De Yoreo model. NA of both viral strains forms a more stable bond with SA than HA, and dissociates 3 to 7 times slower. It is reasoned that the higher stability compensates for the lesser amount of NA compared to HA that is typically found on the viral envelope. The unbinding forces of the cluster of SAPEGLA increased gradually with the number of bonds in the cluster and the dissociation kinetics follow the theoretically predicted trend. The dissociation rate of NA was found to be about 6 times higher than its catalytic rate, indicating that multiple bonds are needed for cleavage of SA. The dissociation rate of N1 is on the same order as that of H3, suggesting that these similarities between the two strains favor transmissibility. The thermal stability of the HA-dPGSA bond is higher than the HA-SAPEGLA reaching that of three to four single bonds, proving specificity and cooperativity. Such an enhancement could not be observed for the binding of NA. This thesis also shows that SMFS could be used as a tool to screen antiviral inhibitors in competitive binding assays, which may contribute insight into the design of antiviral inhibitors on the single molecule level.
Guillet, Dominique. "Spatio-temporal image correlation spectroscopy: Extension to three dimensions and application to biological systems." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110545.
Повний текст джерелаL'objet de cette thèse est de présenter des travaux faits à l'aide de la spectroscopie par corrélation spatiotemporelle d'images (STICS), une technique qui utilise les fluctuations d'intensité dans une série d'images capturées à l'aide d'un microscope par fluorescence pour calculer la fonction complète de corrélation spatiotemporelle, et ainsi mesurer la dynamique du transport de protéines à l'intérieur de cellules vivantes. L'évolution temporelle de cette fonction de corrélation donne de l'information sur la direction et la vitesse d'un flot de particules fluorescentes présentes dans la série d'images. Tout d'abord, une nouvelle application de la technique en biologie végétale est présentée. Lors de la division cellulaire végétale, le transport du matériel membranaire nécessaire à la formation de la plaque cellulaire requiert une grande précision dans la coordination du transport et de la livraison des vésicules de sécrétion. Dans cette thèse, STICS est utilisée pour mesurer la dynamique de ces vésicules pendant la division cellulaire végétale. Les résultats obtenus révèlent l'existence de trois phases dans le transport des vésicules de sécrétion au site de division cellulaire, chacune présentant une échelle de vitesse et des motifs de mouvement caractéristiques qui se reflètent dans le taux de croissance de la plaque cellulaire. Dans un deuxième temps, le développement de STICS pour inclure l'analyse de la troisième dimension spatiale est présenté. Cette nouvelle technique, appelée STICS 3D, permet l'étude de dynamiques en trois dimensions, ce qui est plus pertinent que la version deux-dimensionnelle pour les tissus et les cellules non adhérentes, qui ont un environnement intrinsèquement 3D. Des simulations par ordinateur ont été effectuées pour déterminer l'exactitude, la précision et les limites de la technique pour un éventail de paramètres comme la vitesse, le nombre d'images et la résolution dans la troisième dimension spatiale ainsi que la densité des populations immobiles et en mouvement. Une comparaison entre les résultats obtenus avec STICS et la nouvelle version 3D de la technique est également présentée.
Brereton, Luke James. "A study of shear-force microscopy and its application to liquid-crystal and biological systems." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266886.
Повний текст джерелаLy, Hoang Khoa [Verfasser], and Peter [Akademischer Betreuer] Hildebrandt. "Application of Surface Enhanced Raman Spectroscopy to Biological Systems / Hoang Khoa Ly. Betreuer: Peter Hildebrandt." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2013. http://d-nb.info/1032313218/34.
Повний текст джерелаPage, Kristian. "Evaluation of Raman spectroscopy for application in analytical astrobiology : the application of Raman spectroscopy for characterisation of biological and geological materials of relevance to space exploration." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5716.
Повний текст джерелаARU, VIOLETTA. "Application of NMR-based metabolomics techniques to biological systems: a case study on bivalves." Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266762.
Повний текст джерелаFeldman, Theodore Charles. "Development of New Tools for Single-Molecule Force Spectroscopy & The Application of these Tools to Mapping the Role of Force Directionality in the Actin Mechanome." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:23845490.
Повний текст джерелаEngineering and Applied Sciences - Applied Physics
Claunch, Elizabeth Carson. "Application of Functional Amyloids in Morphological Control and in Self-assembled Composites." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23209.
Повний текст джерелаFunctional amyloids also provide a means of creating a low energy process for composites. Poor fiber/matrix bonding and processing degradation have been observed in previous WG based composites. This study aims to improve upon these flaws by
implementing a self-assembly process to fabricate self-reinforced wheat gluten composites. These composites are processed in aqueous solution at neutral pH by allowing the fibers to form in a matrix of unassembled peptides. The fiber and the matrix are formed from the same solution, thus the two components create a compatible system with ideal interfacial interaction for a composite. The fibers in the composite are about 10 microns in diameter and can be several millimeters long. It has been observed that the number of fibers present along the fracture surface influences the modulus of the composite. In this study, self-assembled wheat gluten composites are formed and then characterized with 3-point bend (3PB) mechanical testing, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy.
Master of Science
Nony, Laurent. "Analyse de la microscopie de force dynamique : application à l'étude de l'ADN." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2000. http://tel.archives-ouvertes.fr/tel-00008804.
Повний текст джерелаMosconi, Francesco. "Fluctuations in biological molecules: tools to probe mechanical and structural properties of DNA and proteins." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3426746.
Повний текст джерелаIcard, Arcizet Delphine. "Modifications mécaniques et biologiques induites dans des cellules en culture par application locale d'une force contrôlée." Phd thesis, Université Paris-Diderot - Paris VII, 2007. http://tel.archives-ouvertes.fr/tel-00188112.
Повний текст джерелаNous avons conçu un dispositif de pinces optiques contrôlées par une boucle de rétroaction, qui permet d'appliquer aux cellules une force locale constante, via des microbilles liées aux intégrines.
Nous pouvons ainsi mesurer la fonction de fluage de chaque cellule et en tirer une estimation de sa rigidité. Des observations simultanées en épifluorescence permettent par ailleurs d'évaluer les effets de l'application de la force sur la répartition d'actine locale.
Nous avons constaté que les cellules se rigidifient sous l'application prolongée d'une force, tout en gardant le même comportement rhéologique : une fonction de fluage en loi de puissance du temps, J(t) = At^(alpha), où A décroît aux temps longs. Cette rigidification est couplée à un recrutement d'actine au niveau des contacts et au sein du réseau cytsoquelettique (jusqu'à plusieurs µm du point d'application de la force). De plus, les dynamiques de ces deux phénomènes semblent fortement corrélées. Ce travail présente une évaluation de la dynamique de renforcement cellulaire sous contrainte, et ouvre des perspectives prometteuses vers l'élucidation des phénomènes intervenant dans la mécanotransduction.
Andersson, Magnus. "Construction of force measuring optical tweezers instrumentation and investigations of biophysical properties of bacterial adhesion organelles." Doctoral thesis, Umeå : Department of Physics, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1425.
Повний текст джерелаChornokur, Ganna. "Photoluminescence spectroscopy of bioconjugated quantum dots and their application for early cancer detection." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002801.
Повний текст джерелаDarcy, Michael Augusto. "High Force Applications of DNA Origami Devices." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1619092851712077.
Повний текст джерелаMosconi, Francesco. "Fluctuations in biological molecules : tools to probe mechanical and structural properties of DNA and proteins." Paris 6, 2008. http://www.theses.fr/2008PA066344.
Повний текст джерелаAghaaminiha, Mohammadreza. "Application of Molecular Simulations and Machine Learning Methods to Study Biological and Metallic Interfaces in Aqueous Environment." Ohio University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou162818080313617.
Повний текст джерелаAghaaminiha, Mohammadreza. "Application of Molecular Simulations and Machine Learning Methods to Study Biological and Metallic Interfaces in Aqueous Environment." Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou162818080313617.
Повний текст джерелаGiatsidis, Giorgio. "Effetti biologici delle forze meccaniche esterne sui tessuti molli: ottimizzazione preclinica per l'applicazione translazionale in chirurgia rigenerativa. Biological effects of external mechanical forces on soft tissues: preclinical optimization for translational application in regenerative surgery." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424960.
Повний текст джерелаLa chirurgia ricostruttiva si basa sul trasferimento di tessuti da un distretto corporeo ad un altro al fine di riparare un difetto tissutale causato da un trauma, un tumore, una malattia cronica, o una malformaizoen congenita. Questo trasferimento chirurgico compromette la vascolarizzazione (e quindi il support metabolico) dei tessuti trasferiti, mettendoli a rischio per complicanze ischemiche quali la necrosi, laguarigione inefficace delle ferite, o la sovrainfezione batterica. L'induzione di fenomeni angiogenici nei tessuti prima della chirurgia (pre-condizionamento) limita le complicanze ischemiche e migliora I risultati chirurgici; tuttavia, pochissime strategie di pre-condizionamento sono oggi disponibili nella pratica clinica. Il primo obiettivo di questa ricerca era di migliorare gli attuali standard in chirurgia ricostruttiva attraverso lo sviluppo di tecniche traslazionali in grado di aumentare la vascolarizzazione dei tessuti in maniera efficace e sicura. Al fine di raggiungere tale obiettivo abbiamo ottimizzato, usando modelli preclinici animali rappresentativi di condizioni cliniche controllate, un metodo che adopera una stimolazione meccanica esterna non invasiva tramite pressione negativa (Espansione Volumetrica Esterna, EVE) per precondizionare I tessuti attraverso l'induzione di fenomeni angiogenici causati da una ischemia transitoria. Tramite questa strategia di ottimizzazione sequenziale in un modello murino abbiamo definite i parametri di trattamento ottimali di EVE (frequenza, livelli di pressione, durata, interfaccia di trattamento) in grado di bilanciare l'induzione di angiogenesis con l'attenuazione del danno ischemico causato ai tessuti, e con la durata di trattamento. L'ottimizzazione di EVE (brevi, cicliche stimulazioni a suzione moderata) ha dimostrato la capacità di raddoppiare la densità vascolare dei tessuti stimulati dopo solo 5 giorni di trattamento. I nostri risultati hanno anche dimostrato che l'uso di interfacce di trattamento a micro-deformazione garantisce il mantenitmento degli stessi effetti biologici di EVE ma allo stesso tempo reduce il danno cutaneo causato ai tessuti tramite la distribuzione delle forze meccaniche su tutto il tessuto stimulato. I nostri modelli sperimentali hanno confermato che l'ottimizzazione di EVE permette di aumentare significativamente (+20-30%) la sopravvivenza dei tessuti trasferiti (ad esempio il tessuto adiposo), e che gli stessi effetti possono essere osservati in modelli di vascolarizzazione cutanea patologica (ad esempio la cute di soggetti affetti da diabete di tipo 2). Inoltre, abbiamo confermato che EVE induce la vascolarizzazione e la proliferazione (adipogenesi) dei tessuti molli sia quando utilizzara come metodo di pre-condizionamento (prima della chirurgia) dei tessuti sia quando utilizzata come metodo di post-condizionamento (dopo la chirurgia). Come secondo obiettivo di questa ricerca abbiamo integrato le conoscenze acquisite sull'applicazione di EVE ai tessuto molli all'uso di una matrice adiposa allogenica (AAM) -ottenuta tramite decellularizzazione di tessuto adipose umano, caratterizzata da proprietà bio-mimetiche, e realizzata in una formulazione iniettiabile "pronta all'uso" - con lo scopo di sviluppare una strategia innovativa e mini-invasiva per la rigenerazione in vivo di tessuto molli. In un modello animale abbiamo testato il potenziale della AAM di rigenerare i tessuti molli quando utilizzata in combinazione con EVE. Questa strategia ha portato ad un significativo aumento volumetrico (+50-80% a 12 settimane) ed un miglioramento della struttura istologica dei tessuti molli ricostruiti in comparazione ai risultati ottenuti con le terapie standard attuali (innesti di tessuto adiposo). Abbiamo evidenziato come la AAM sia in grado di indurre sia fenomeni adipogenici che fenomeni angiogenici: l'applicazione combinate di AAM e innesti di tessuto adiposo, invece, mitigano I risultati ottenibili con l'uso esclusivo della AAM. In conclusion, i nostril studi suggeriscono che EVE è in grado di migliorare i risultati ottenibili in chirurgia ricostruttiva attraverso un incremento, sicuro e rapido, della vascolarizzazione dei tessuto molli, in aggiunta all'efftto adipogenico (mediato da stimolazione meccanica diretta ed edema dei tessuti) gia descritto nella precedente letteratura e qui confermato dai nostril risultati. L'utilizzo di EVE con l'AAM, invece, può, efficacemente e sinergisticamente, indurre fenomeni rigenerativi dei tessuto molli in vivo. Questi principi traslazionali sono pronti per essere validati in trial clinici e, qualora I loro risultati venissero confermati, potrebbero porre le basi per lo sviluppo di nuovi paradigm terapeutici in chirurgia ricostruttiva e in chirurgia rigenerativa, per il beneficio di un grande numero di pazienti
Tilley, Jennifer Miriam Ruth. "In vivo adaptation of tendon material properties in healthy and diseased tendons with application to rotator cuff disease." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:16b5eb5a-afcc-4ab2-9cce-c2e6241c6996.
Повний текст джерелаWhitaker, Darren Andrew. "Method development for the application of vibrational spectroscopy to complex organic-inorganic materials in astrobiology : a systematic development of Raman spectroscopy and related analytical methods to the structural chemistry at organic (biological) and inorganic (mineralogical) interfaces of material assemblies relevant to astrobiology and inter-planetary science." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7332.
Повний текст джерелаWhitaker, Darren A. "Method Development for the Application of Vibrational Spectroscopy to Complex Organic-Inorganic Materials in Astrobiology. A Systematic Development of Raman Spectroscopy and Related Analytical Methods to the Structural Chemistry at Organic (Biological) and Inorganic (Mineralogical) Interfaces of Material Assemblies Relevant to Astrobiology and Inter-Planetary Science." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7332.
Повний текст джерелаReichert, Verena Maria Charlotte. "Application of a human bone engineering platform to an in vitro and in vivo breast cancer metastasis model." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/53212/1/Verena_Reichert_Thesis.pdf.
Повний текст джерелаHabib, Lamice. "Étude des propriétés membranaires des vésicules lipidiques incorporant des triterpènes oxygénés bioactifs d'origine végétale : application à la cucurbitacine E et à l'érythrodiol." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10022/document.
Повний текст джерелаCucurbitacin E and erythrodiol are natural oxygenated triterpenes having respectively, a tetra and pentacyclic skeleton. They are known for their numerous biological properties. In this thesis, we studied their interaction with the membranes of lipid vesicles to better understand their pharmacodynamics. We have prepared liposomes in the absence and presence of cucurbitacin E and erythrodiol using the reverse phase evaporation technique followed by extrusion, the hydration of lipid film and the ethanol injection techniques. The physicochemical characteristics of lipid vesicles incorporating or not the triterpenic molecules were investigated by appropriate techniques. The determination of cucurbitacin E and erythrodiol in the vesicles by high performance liquid chromatography showed high incorporation efficiencies of both triterpenes. Size measurements obtained by dynamic light scattering showed that liposomes incorporating triterpenes were smaller than empty liposomes. The images obtained by transmission electron microscopy confirmed the formation of spherical vesicles. Measurements of vesicles dimensions by atomic force microscopy (AFM) demonstrated that liposomes incorporating cucurbitacin E were higher and more resistant to the force exerted by the AFM tip than the blank liposomes. Liposomes incorporating erythrodiol were more fragile and tend to break up into lipid bilayers on the mica surface. Results obtained by differential scanning calorimetry suggested that cucurbitacin E is localized at the polar-apolar interface of the liposomal membrane while erythrodiol is inserted between the acyl chains of the phospholipids leading to the formation of heterogeneous lipid domains. The release kinetics of the sulforhodamin B encapsulated into the aqueous phase and measured by fluorescence spectroscopy revealed that the liposomal membrane becomes in the presence of cucurbitacin E, more permeable to this probe. The overall results suggest that cucurbitacin E and erythrodiol affect differently
Carvalho, Filomena A. 1976. "Studying single-molecule protein interactions and its biological and biomedical applications by AFM-based force spectroscopy." Doctoral thesis, 2012. http://hdl.handle.net/10451/7426.
Повний текст джерелаThe use of the knowledge and technology generated by nanomedicine research is slowly gaining its way into the clinical areas. Nanomedicine can be defined as the application of nanotechnologies in medicine, to monitor, diagnose and cure diseases, by using molecular knowledge of the human organism to maintain and improve human health at the molecular scale. In this thesis, we proposed to use force spectroscopy based on atomic force microscopy, a nanotechnology approach, to understand the single-molecule mechanisms involved in two different biomedical relevant systems: (i) Fibrinogen interaction with human blood cell membranes (erythrocytes and platelets) receptors. Increased plasma fibrinogen levels are associated with increased erythrocyte aggregation in cardiovascular diseases. With our results, we identified a specific binding between fibrinogen and an erythrocyte integrin receptor with a β3 or β3-like subunit. This interaction decreases significantly upon erythrocyte aging. We presume that young erythrocytes are the main contributors to the cardiovascular diseases associated with increased fibrinogen content in blood. (ii) Dengue virus (DENV) capsid (C) protein interaction with lipid droplets or lipoproteins. Lipid droplets (LDs) and/or lipoproteins may play an important role on Dengue virus pathogenesis. Our results could explain the key processes occurring in vivo on the Dengue virus replication. We found that DENV C N-terminal region is crucial for the interaction with LDs and very low density lipoproteins (VLDL), requiring the presence of potassium and intrinsic protein(s). Also, pep14-23, a peptide based on the DENV C N-terminal conserved region, inhibits the DENV C-LDs interaction. These findings may be important for the development of C protein-targeted treatments for DENV infections. The main findings described on both of these studies contribute to the establishment of atomic force microscopy as a biomedical tool used to improve knowledge on the molecular mechanisms associated with the development of diseases and their effective treatment.
Durante as últimas décadas, a Nanomedicina tem vindo a se tornar numa área científica emergente e em elevada expansão. O termo “Nanomedicina” é definido como a aplicação de técnicas nanotecnológicas em medicina, através do conhecimento, ao nível molecular, do organismo humano para manutenção e melhoria da saúde humana. Através da nanotecnologia é possível criar e desenvolver equipamentos que permitam a análise de sistemas in vivo ao nível molecular. Nos últimos anos, o grau de aceitação ao nível clínico do uso destas nanotecnologias tem vindo a aumentar, contudo, ainda há muito a desenvolver na área da aplicação da Nanomedicina na monitorização, diagnóstico e possível cura de doenças. Atualmente, as grandes empresas farmacêuticas estão mais recetivas à aplicação destas novas tecnologias, mas há sempre a considerar a relação custo/beneficio, bem como os eventuais riscos associados à sua aplicação. Neste trabalho foi utilizada, maioritariamente, a técnica de espectroscopia de força através de um microscópio de força atómica, para identificar interações específicas entre moléculas, conhecer possíveis mecanismos de desencadeamento da doença e apontar possíveis alvos de terapêutica e diagnóstico de duas patologias distintas, doença cardiovascular e infeção pelo vírus da Dengue. Estas duas diferentes aplicações do microscópio de força atómica são exemplos de como é possível a utilização deste equipamento como método de diagnóstico e caracterização funcional aplicado à área da Nanomedicina: Parte I: Estudo da interação do fibrinogénio com um recetor de membrana eritrocitário, na saúde e na doença. O aumento dos níveis de fibrinogénio conduz a alterações das propriedades reológicas do sangue, tais como o aumento da viscosidade plasmática, da agregação eritrocitária e da trombogénese, juntamente com alterações da reatividade vascular e da integridade endotelial. Essas alterações intensificam as complicações na circulação sanguínea periférica em patologias cardiovasculares. A agregação eritrocitária tem adquirido um elevado interesse na avaliação do risco de eventos cardiovasculares primários ou secundários, uma vez que é principalmente influenciada pelo aumento dos níveis plasmáticos de fibrinogénio e de lípidos. É nestas condições clínicas e na fase não aguda da doença que se torna mais premente a determinação da agregação eritrocitária como indicador do risco cardiovascular associado. Um estudo detalhado das interações entre eritrócitos e moléculas de fibrinogénio, de modo a compreender as consequências do seu aumento em patologias cardiovasculares, revelou-se assim necessário. O nosso primeiro trabalho demonstrou a ligação entre moléculas de fibrinogénio e um recetor anteriormente desconhecido na membrana eritrocitária, com afinidade comparável mas menor tempo de vida que a ligação fibrinogénio-plaqueta. A interação fibrinogénio-plaqueta, essencial na coagulação, depende de um recetor da membrana plaquetária, a glicoproteína αIIbβ3 (GP αIIbβ3). O recetor eritrocitário que identificámos não é tão fortemente influenciado pela presença de cálcio nem de eptifibatide, um inibidor específico da GP αIIbβ3, mas a sua inibição na presença de eptifibatide indica que o recetor é semelhante à integrina αIIbβ3. Os resultados obtidos com sangue de doentes com trombastenia de Glanzmann (GT, uma doença hemorrágica hereditária rara causada por deficiência na GP αIIbβ3) mostraram uma deficiência também na interação fibrinogénio-eritrócito. A correlação com os dados genéticos demonstrou que uma das unidades do recetor do fibrinogénio nos eritrócitos é um produto da expressão do gene da β3. O estudo seguinte, efetuado com o intuito de relacionar a interação fibrinogénioeritrócito com o processo de senescência celular, indicou que o recetor para o fibrinogénio na membrana no eritrócito pode desaparecer, ficar “mascarado” ou tornar-se disfuncional com o processo in vivo de senescência celular. Os resíduos de ácido siálico parecem também ter uma função importante como promotores da interação fibrinogénio-eritrócito. A diminuição desta interação durante o processo de senescência poderá estar largamente associada à progressiva depleção de ácidos siálicos na população de eritrócitos mais velhos. Sabendo que a população de eritrócitos mais novos se liga com maior afinidade a moléculas de fibrinogénio, pudemos concluir que a população de eritrócitos mais jovens poderá ter a maior contribuição para as doenças cardiovasculares associadas ao aumento dos níveis plasmáticos de fibrinogénio. O vírus da Dengue é o responsável pelo maior número de casos de febre hemorrágica em todo o mundo, sendo estimado que cause mais de 20 mil mortes por ano. Não existe atualmente uma vacina ou tratamento específico para a Dengue, devido (em parte) à falta de conhecimento sobre os mecanismos moleculares de alguns passos importantes do ciclo de vida viral. O vírus da Dengue é do género Flavivirus, família Flaviviridae, à qual também pertencem os vírus da febre-amarela, do Nilo Ocidental e da hepatite C. Apesar de resultarem em patologias e sintomatologias diferentes, os Flaviviridae infetam o fígado e os epitélios vasculares do hospedeiro, podendo também infetar outros órgãos. Nestas infeções, a estiatose hepática é causada pela disfunção geral do metabolismo lipídico, observando-se um aumento do número e tamanho de corpúsculos lipídicos intracelulares, uma desordem da estrutura membranar, bem como a alteração dos níveis e composição das lipoproteínas plasmáticas. Foi recentemente descoberto que a proteína da cápside (C) do vírus da Dengue interage com os corpúsculos lipídicos intracelulares, influenciando a replicação viral. Também se sabe que o vírus da hepatite C forma lipo-viro-partículas, uma conjugação entre lipoproteínas e viriões, sendo mais infeciosas que os próprios vírus livres. Estas evidências mostram a importância dos sistemas lipídicos no ciclo de vida destes vírus, embora os mecanismos moleculares subjacentes à interação da proteína C do vírus da Dengue com estes sistemas lipídicos ainda sejam desconhecidos. O nosso estudo focou-se na importância da interação da proteína da cápside do vírus da Dengue com sistemas lipídicos do hospedeiro (corpúsculos lipídicos e/ou lipoproteínas), que influenciam vários passos importantes do ciclo de vida deste vírus. Através da aplicação da técnica de espectroscopia de força, os resultados obtidos permitiram concluir que a interação da proteína C com corpúsculos isolados de linhas celulares é forte, específica, dependente do ião potássio e de proteína(s) intrínseca(s) dos corpúsculos. De seguida, desenvolveu-se um péptido (pep14-23), homólogo de um segmento da região N-terminal da proteína C do vírus da Dengue, que concluiu-se ter a capacidade de inibir a interação entre a proteína C e os corpúsculos. Tal desenvolvimento permitirá, no futuro, otimizar esta inibição com péptidos derivados do pep14-23, testando a sua atividade anti-viral contra o vírus da Dengue e outros Flavivirus. As interações da proteína C com as lipoproteínas plasmáticas humanas VLDL e LDL foram também testadas, observando-se interação específica apenas com VLDL. A dependência do ião potássio, tal como nos corpúsculos lipídicos, e a especificidade na ligação às VLDL levou a inferir que a interação depende de proteína(s) presentes nas VLDL. Interessantemente, a apolipoproteína E, uma das proteínas das VLDL (e que não está presente nas LDL), tem semelhança estrutural e de sequência com a perilipina 3 (TIP47), uma das proteínas mais abundantes nos corpúsculos lipídicos. Surge então a possibilidade de estes serem os alvos moleculares da proteína C em cada um dos sistemas lipídicos. Este tipo de interação sugere também que o vírus da Dengue, tal como o da hepatite C, pode formar lipo-viro-partículas, o que explicaria alguns dos sintomas da doença.
FP7-PEOPLE International Research Staff Exchange Scheme (IRSES; project MEMPEPACROSS, European Union); Fundação para a Ciência e a Tecnologia – Ministério da Ciência, Tecnologia e Ensino Superior (FCT-MCTES, projetos CONC-REEQ/140/2001, PTDC/SAU-OSM/73449/2006, PTDC/QUI-BIQ/112929/2009, PTDC/QUI/69937/2006 e PTDC/QUIBIQ/119509/2010); Fundação Calouste Gulbenkian (FCG, Portugal; Project Research in Life Sciences Frontiers 2010 e Programa de Estímulo à Investigação 2009) e FCT-CAPES Portugal-Brazil (Coordenação de Aperfeiçoamento de Pessoal a nível Superior)
Zheng, Jieru. "Theory of biological and biologically-inspired molecules and intermolecular interactions : application to electron transfer, two-photon spectroscopy, and protein-DNA binding." 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3318876.
Повний текст джерелаSelhuber-Unkel, Christine [Verfasser]. "Biological adhesion on nanopatterned substrates studied with force spectroscopy and microinterferometry / presented by Christine Selhuber." 2006. http://d-nb.info/982380135/34.
Повний текст джерелаShen, Hsu-Tao, and 沈續濤. "Design and Application of Miniaturized Automatic Dielectric Spectroscopy System for Biological Materials." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/46052251033250514484.
Повний текст джерела國立臺灣大學
醫學工程學研究所
104
Biosensors that use microwave resonators are compact, easy to operate, low-cost, and capable of real-time monitoring. These advantages, combined with eliminating the need for sample pretreatment, make microwave biosensors the object of widespread attention. However, due to their relatively large size and the expensive laboratory instruments necessary for conducting measurements, they cannot be integrated into general consumer electronic products. With current development in information technology and popularity of portable smart devices, miniature biosensors have become a development trend for the future. In this study, a microwave biosensor system was developed using the technology and process of integrated circuit (IC) and printed circuit board (PCB) to measure, by automatic feedback control, sample-induced capacitance and impedance which correspond respectively to real and imaginary parts of relative permittivity. The device exhibited small size, low power consumption, low operating frequency, label-free detection, high sensitivity, and low cost. In addition, the signal to noise ratio increased with the integration interval. Function validation and sample analysis were performed on the biosensor system. In order to increase the convenience of the detection process, an automated a graphical user interface was developed. In summary, the described system is capable of rapid sample analysis and when integrated into smart device platforms, is a potentially valuable tool for IOT service.
zhang, xinyu. "Preparation of modified DNA molecules for multi-Spectroscopy Application." Thesis, 2018. http://hdl.handle.net/10754/630132.
Повний текст джерелаHlongwane, Mokgadi Miranda. "Extension of the linear dynamic range for high resolution continuum source atomic absorption spectrometry and its application in the analysis of biological samples." 2013. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000744.
Повний текст джерелаRecently, traditional electro-thermal atomic absorption spectrometry has lost its popularity to other multi-element spectrometric techniques. Limited linear determination range, which is usually two orders of magnitude, is one of the reasons for the loss. As a result, tens of calibration standards and diluted samples have become an indispensable part of the electro-thermal atomic absorption spectrometric analysis, particularly if numerous samples containing a broad concentration range of analytes are to be analysed. The objective of this work was to establish the mechanism of absorption signals for high concentrations of analyte atoms in the absorption volume. Secondly, to employ the findings for HR-CS ET-AAS data quantification, within a broad range of analyte concentrations. It was expected that the sought algorithm would permit the use of the most sensitive analytical lines or those less prone to interferences, independent of the concentration of the respective analyte in the sample.