Academic literature on the topic 'FILM'S CYTOTOXICITY'

Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) is an important bioactive material for bone tissue reconstruction, due to its highly thermodynamic stability at a physiological pH without bio-resorption. In the present study, the Ag:HAp and the corresponding Ag:HAp + D3 thin films (~200 nm) coating were obtained by vacuum deposition method on Ti substrate. The obtained samples were exposed to different UV irradiation times, in order to investigate the UV light action upon thin films, before considering this method for the thin film’s decontamination. The effects of UV irradiation upon Ag:Hap + D3 are presented for the first time in the literature, marking a turning point for understanding the effect of UV light on composite biomaterial thin films. The UV irradiation induced an increase in the initial stages of surface roughness of Ag:HAp thin film, correlated with the modifications of XPS and FTIR signals. The characteristics of thin films measured by AFM (RMS) analysis corroborated with XPS and FTIR investigation highlighted a process of recovery of the thin film’s properties (e.g., RMS), suggesting a possible adaptation to UV irradiation. This process has been a stage to a more complicated UVA rapid degradation process. The antifungal assays demonstrated that all the investigated samples exhibited antifungal properties. Moreover, the cytotoxicity assays revealed that the HeLa cells morphology did not show any alterations after 24 h of incubation with the Ag:HAp and Ag:HAp + D3 thin films.

This work attempts to understand the behaviour of Ge-induced cytotoxicity of germanium-doped hydrogen-free diamond-like carbon (DLC) films recently thoroughly studied and published by Jelinek et al. At a low doping level, the films showed no cytotoxicity, while at a higher doping level, the films were found to exhibit medium to high cytotoxicity. We demonstrate, using surface-sensitive methods—two-angle X-ray-induced core-level photoelectron spectroscopy (ARXPS) and Low Energy Ion Scattering (LEIS) spectroscopy, that at a low doping level, the layers are capped by a carbon film which impedes the contact of Ge species with tissue. For higher Ge content in the DLC films, oxidized Ge species are located at the top surface of the layers, provoking cytotoxicity. The present results indicate no threshold for Ge concentration in cell culture substrate to avoid a severe toxic reaction.

Bombyx mori Sericin films were prepared with PEG-DE as cross linking agent. The main physical properties, structure characteristics, cytotoxicity and cell proliferation of sericin films were measured and analyzed. The result showed that sericin films prepared by cast method containing 30-40% of PEG-DE, showed good mechanical properties. PEG-DE caused the changes of the condensed structure of sericin films. The films prepared from sericin extracted both from silk-gland and cocoon shell showed good cytocompatibility. Silk sericin films with PEG-DE had no obvious cytotoxicity to cells.

Recently, silver-based nanoparticles have been proposed as components of wound dressings due to their antimicrobial activity. Unfortunately, they are cytotoxic for keratinocytes and fibroblasts, and this limits their use. Less consideration has been given to the use of AgCl nanoparticles in wound dressings. In this paper, a sustainable preparation of alginate AgCl nanoparticles composite films by simultaneous alginate gelation and AgCl nanoparticle formation in the presence of CaCl2 solution is proposed with the aim of obtaining films with antimicrobial and antibiofilm activities and low cytotoxicity. First, AgNO3 alginate films were prepared, and then, gelation and nanoparticle formation were induced by film immersion in CaCl2 solution. Films characterization revealed the presence of both AgCl and metallic silver nanoparticles, which resulted as quite homogeneously distributed, and good hydration properties. Finally, films were tested for their antimicrobial and antibiofilm activities against Staphylococcus epidermidis (ATCC 12228), Staphylococcus aureus (ATCC 29213), Pseudomonas aeruginosa (ATCC 15692), and the yeast Candida albicans. Composite films showed antibacterial and antibiofilm activities against the tested bacteria and resulted as less active towards Candida albicans. Film cytotoxicity was investigated towards human dermis fibroblasts (HuDe) and human skin keratinocytes (NCTC2544). Composite films showed low cytotoxicity, especially towards fibroblasts. Thus, the proposed sustainable approach allows to obtain composite films of Ag/AgCl alginate nanoparticles capable of preventing the onset of infections without showing high cytotoxicity for tissue cells.

In this study, PLA/sericin films at various contents of sericin were prepared. Thermal properties, in vitro degradability and in vitro cytotoxicity of the films were characterized. The results illustrated that the incorporation of sericin into PLA matrix crucially affected thermal properties and biodegradability of the films and also enhanced human fibroblast cells attachment and proliferation on the film surface.

Oral mucoadhesive systems, such as polymer films, are among innovative pharmaceutical products. These systems can be applied in swallowing problems and can also be used in geriatrics and paediatrics. In our earlier work, we successfully formulated buccal mucoadhesive polymer films, which contained cetirizine-hydrochloride (CTZ) as the API. The present study focused on investigating the stability and permeability of the prepared films. The stability of the films was studied with an accelerated stability test. During the stability test, thickness, breaking hardness and in vitro mucoadhesivity were analysed. Furthermore, the interactions were studied with FT-IR spectroscopy, and the changes in the amount of the API were also monitored. Cytotoxicity and cell line permeability studies were carried out on TR 146 buccal cells. Compositions that can preserve more than 85% of the API after 6 months were found. Most of the compositions had a high cell viability of more than 50%. Citric acid (CA) decreased the stability and reduced every physical parameter of the films. However, cell line studies showed that the permeability of the films was enhanced. In our work, we successfully formulated CTZ-containing buccal films with adequate stability, high cell viability and appropriate absorption properties.

Biopolymeric films with silver sulfadiazine (AgSD) are proposed as an alternative to the occlusive AgSD-containing creams and gauzes, which are commonly used in the treatment of conventional burns. While the recognized cytotoxicity of AgSD has been reported to compromise its use as an antimicrobial drug in pharmaceuticals, this limitation can be overcome by developing sustained-release formulations. Microporous materials as zeolites can be used as drug delivery systems for sustained release of AgSD. The purpose of this work was the development and characterization of chitosan/zeolite composite films to be used as wound dressings. Zeolite was impregnated with AgSD before the production of the composite films. The physicochemical properties of zeolites and the films were evaluated, as well as the antimicrobial activity of the polymeric films and the cytotoxicity of the films in fibroblasts Balb 3T3/c. Impregnated zeolite exhibited changes in FTIR spectra and XRD diffraction patterns, in comparison to non-impregnated composites, which corroborate the results obtained with EDX-SEM. The pure chitosan film was compact and without noticeable defects and macropores, while the film with zeolite was opaquer, more rigid, and efficient against Candida albicans and some gram-negative bacteria. The safety evaluation showed that although the AgSD films present cytotoxicity, they could be used in a concentration-dependent fashion.

Bupropion is an antidepressant used in the treatment of smoking. The purpose of this study was to prepare controlled-release hydrogel films for buccal administration of bupropion and investigate its physicochemical and cytotoxic properties. The films were prepared from ultrapure sodium carboxymethylcellulose, hydroxypropylmethylcellulose K4M, and medium-viscosity chitosan. Evaluation of film physicochemical characteristics was based on scanning electron microscopy, bupropion content, mechanical strength (burst strength, relaxation, resilience, and traction), and cytotoxicity. Bupropion content in bilayer films was 121 mg per 9 cm2. The presence of bupropion modified film mechanical strength, but did not compromise the use of this pharmaceutical form. As shown by the cytotoxicity results, films containing bupropion did not cause cellular damage. Bupropion administration in the form of hydrogel films is a potentially useful alternative in the treatment of smoking.

A novel type of porous films based on the ZnO-incorporated chitosan–poly(methacrylic acid) polyelectrolyte complex was developed as a wound healing material. The structure of porous films was established by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) analysis. Scanning electron microscope (SEM) and porosity studies revealed that the pore size and porosity of the developed films increased with the increase in zinc oxide (ZnO) concentration. The porous films with maximum ZnO content exhibited improved water swelling degree (1400%), controlled biodegradation (12%) for 28 days, a porosity of 64%, and a tensile strength of 0.47 MPa. Moreover, these films presented antibacterial activity toward Staphylococcus aureus and Micrococcus sp. due to the existence of ZnO particles. Cytotoxicity studies demonstrated that the developed films had no cytotoxicity against the mouse mesenchymal stem (C3H10T1/2) cell line. These results reveal that ZnO-incorporated chitosan-poly(methacrylic acid) films could be used as an ideal material for wound healing application.

The intrapulmonary distribution of inhaled ozone (O3) and induction of site-specific cell injury are related to complex interactions among airflow patterns, local gas-phase concentrations, and the rates of O3 flux into, and reaction and diffusion within, the epithelial lining fluid (ELF). Recent studies demonstrated that interfacial phospholipid films appreciably inhibited NO2 absorption. Because surface-active phospholipids are present on alveolar and airway interfaces, we investigated the effects of interfacial films on O3-reactive absorption and acute cell injury. Compressed films of dipalmitoyl-glycero-3-phosphocholine (DPPC) and rat lung lavage lipids significantly reduced O3-reactive absorption by ascorbic acid, reduced glutathione, and uric acid. Conversely, unsaturated phosphatidylcholine films did not inhibit O3 absorption. We evaluated O3-mediated cell injury using a human lung fibroblast cell culture system, an intermittent tilting exposure regimen to produce a thin covering layer, and nuclear fluorochrome permeability. Exposure produced negligible injury in cells covered with MEM. However, addition of AH2 produced appreciable (<50%) cell injury. Film spreading of DPPC monolayers necessitated the use of untilted regimens. Induction of acute cell injury in untilted cultures required both AH2 plus very high O3 concentrations. Addition of DPPC films significantly reduced cell injury. We conclude that acute cell injury likely results from O3 reaction with ELF substrates. Furthermore, interfacial films of surface-active, saturated phospholipids reduce the local dose of O3-derived reaction products. Finally, because O3 local dose and tissue damage likely correlate, we propose that interfacial phospholipids may modulate intrapulmonary distribution of inhaled O3 and the extent of site-specific cell injury.

Stent is one of the coronary angioplasty techniques that expands the narrowed coronary arteries due to the accumulation of fat, cholesterol and other substances in the lumen of the arteries. The major complication of stent is restenosis. Current development of drug-eluting stents shows successfully reduce the occurrence of restenosis. Other than using drugs, electrostatic self assembled (ESAd) thin films may be the potential candidates to prevent restenosis.

ESA is a process to fabricate thin films bases on the electrostatic attraction between two oppositely charges. We used this technique to fabricate four PVP films and four PEI films. All films were exanimated by XPS and AFM. XPS data showed our coatings were successfully fabricated on substrates. AFM images revealed PVP coating was uniform, but PEI coatings had different morphologies due to diffusion and pH during the process.

Three preliminary hemocompatibility testes were performed to evaluate the hemocompatibility of the coatings. Platelet adhesion study showed the thin films inhibited platelet adhesion. All thin films were able to inhibit coagulation and were less cytotoxic. The studies suggested the ESA films were potentially hemocompatible.
Master of Science

Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-16T20:28:57Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FabioBonorinoVieira.pdf: 1042169 bytes, checksum: 9005bc8a7b7f41c4b1a750f6f427938e (MD5)
Made available in DSpace on 2018-08-16T20:28:58Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FabioBonorinoVieira.pdf: 1042169 bytes, checksum: 9005bc8a7b7f41c4b1a750f6f427938e (MD5) Previous issue date: 2015-08-31
Due to their favorable properties as chemical stability, corrosion resistance, mechanical properties and biocompatibility, titanium and his alloys have been used for the manufacture of implants and prostheses for biomedical purposes. The stability of these metals and alloys is obtained due to a passivation layer of biocompatible titanium dioxide, naturally formed on the surface. In this work, titanium was anodized using potentiodynamic techniques forming a duplex with a film barrier back sheet type with a structure of type nanotubes on top. This film aims to metal passivation or alloy and enhance the characteristics of the material forward to interactions with the physiological environment. Although this oxide film is considered as a protective intermediate layer between the host tissue and the implant, it is considered the defense system a foreign body, and being very thin (only a few nanometers) and unstable under the action of body fluids. The current corrosion of metals and alloy with oxide coating in Ringer's solution increases towards Ti> Nb> Alloy 46.5% m / m Ti. The polished Nb shows high via cell viability and low genotoxicity. The anodized materials exhibit cytotoxicity and genotoxicity.
Devido suas propriedades favoráveis como estabilidade química, resistência à corrosão, propriedades mecânicas e biocompatibilidade, o titânio e suas ligas vem sendo utilizados para a fabricação de próteses e implantes para fins biomédicos. A estabilidade destes metais e ligas é obtida devido a uma camada de passivação biocompatível de dióxido de titânio, formada naturalmente sobre a superfície. Neste trabalho, o titânio foi anodizado utilizando técnicas potenciodinâmicas formando um filme do tipo duplex com uma camada inferior do tipo barreira com uma estrutura do tipo nanotubos na parte superior. Este filme tem como objetivo a passivação do metal ou da liga e potencializar as características dos materiais frente às interações com o meio fisiológico. Embora esse filme de óxido seja considerado como uma camada intermediária protetora entre os tecidos hospedeiros e o implante, ele é considerado pelo sistema imune, um corpo estranho, e sendo muito fino (apenas alguns nanômetros) e instável sob a ação dos fluidos corporais. A corrente de corrosão dos metais e da liga com o recobrimento de óxido em solução de Ringer aumenta no sentido Ti> Nb> liga 46,5 % m/m Ti. O Nb polido apresenta alta viabilidade celular e baixa genotoxidade. Os materiais anodizados apresentam citotoxidade e genotoxidade.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-29T18:20:33Z No. of bitstreams: 1 alinelucianofilgueiras.pdf: 4846834 bytes, checksum: f046903a257bca51b49b36d371931270 (MD5)
Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-08T12:28:56Z (GMT) No. of bitstreams: 1 alinelucianofilgueiras.pdf: 4846834 bytes, checksum: f046903a257bca51b49b36d371931270 (MD5)
Made available in DSpace on 2017-08-08T12:28:56Z (GMT). No. of bitstreams: 1 alinelucianofilgueiras.pdf: 4846834 bytes, checksum: f046903a257bca51b49b36d371931270 (MD5) Previous issue date: 2017-03-24
Nesta tese investigou-se as interações químicas dos antimicrobianos tinidazol, metronidazol, aztreonam, rifampicina e tetraciclina (TC) adsorvidos sobre superfícies metálicas de nanopartículas de ouro (AuNP) ou prata (AgNP) através das técnicas espectroscópicas de espalhamento Raman intensificado por superfície (SERS), de espalhamento Raman ressonante intensificado por superfície (SERRS) e de absorção no ultravioleta, visível e infravermelho próximo (UV-VIS-NIR). Também foram investigadas, a citotoxidade das AgNP, quitosana (QUIT), TC e das combinações AgNP com quitosana (AgNP+QUIT), e AgNP com QUIT e TC (AgNP+QUIT+TC) frente a células de fibroblastos bovinos. Foram obtidas as imagens de microscopia eletrônica de transmissão (TEM) das bactérias K.pneumoniae e S. aureus na ausência e presença das AgNP. Diferentes rotas sintéticas de AuNP e AgNP foram propostas, com o objetivo de se aprimorar as possíveis aplicações dessas sínteses. As AgNP devem ser pequenas para aplicações em experimentos biológicos e devem estar em ressonância com as radiações excitantes de comprimento de onda em 532, 633 ou 1064 nm quando forem utilizadas nos experimentos SERS. Os espectros SERS dos adsorbatos estudados foram obtidos na ausência e na presença dos modificadores de superfície 2-mercaptoetanol, polivinil álcool (PVA) ou íons cloreto. A presença destes modificadores superficiais permitiu monitorar os mecanismos de adsorção, que levaram a padrões espectrais SERS distintos. A análise dos espectros SERS da rifampicina foi baseada nas modificações observadas na estrutura eletrônica do grupo cromóforo, enquanto que para o tinidazol, metronidazol e aztreonam as diferenças nos padrões espectrais foram devidas a proximidade do sítio de adsorção do analito em relação à superfície metálica. A atribuição vibracional dos espectros Raman e SERS foi baseada em cálculos teóricos obtidos da teoria do funcional de densidade (DFT) das moléculas isoladas ou interagindo com átomos de metal. Este trabalho foi realizado em parceria com o Prof. Dr. Diego Paschoal da Universidade Federal do Rio de Janeiro e com o Prof. Dr. Hélio Ferreira dos Santos da Universidade Federal de Juiz de Fora. As imagens TEM das bactérias K. pneumoniae e S.aureus obtidas na ausência e presença das AgNP+QUIT foram realizadas em colaboração com o Dr. Celso Sant’Ana e o aluno Mateus Eugênio do Instituto Nacional de Metrologia, Qualidade e Tecnologia. Os ensaios de citotoxicidade das diferentes combinações de AgNP frente as células de fibroblastos bovinos foram realizados através do ensaio colorimétrico com brometo de 3, (-4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium (MTT). Este trabalho foi realizado em colaboração com a Profa. Dra. Michele Munk da Universidade Federal de Juiz de Fora.
In this thesis were investigated the chemical interaction of the antimicrobians tinidazole, metronidazole, aztreonam, rifampicin and tetracycline adsorbed on metallic surfaces of gold (AuNP) or silver nanoparticles (AgNP) by using the spectroscopic techniques surface enhanced Raman scattering (SERS), surface enhanced resonance Raman scattering (SERRS) and absorption in ultraviolet, visible and near infrared regions (UV-VIS-NIR). The cytotoxic effects of silver nanoparticles, chitosan (QUIT), tetracycline (TC) and its combinations AgNP with chitosan (AgNP+QUIT), and AgNP with QUIT and TC (AgNP+QUIT+TC) against bovine fibroblast cells were also investigated. The images using transmission electron microscopy (TEM) were obtained from the bacteria K.pneumoniae and S. aureus in the absence and presence of AgNP +QUIT. Different AuNP and AgNP were synthesized, with the aim of improving the possible applications of these syntheses. These have to be small in the biological experiments and should be in resonance with laser lines at 532, 633 or 1064 nm when used in the SERS experiments. The SERS spectra of the studied adsorbates were obtained in the absence and presence of the surfaces modifiers 2-mercaptoethanol, chloride ions or polyvinyl alcohol (PVA). The presence of these surfaces modifiers allowed monitoring adsorption mechanisms, which led to distinct SERS spectral patterns. The analyses of the SERS spectra of rifampicin were based on the observed changes in the electronic structure of the chromophore group, while for the tinidazole, metronidazole and aztreonam the differences in the spectral patterns were due to the proximity of anchor site of the analyte in relation to the metallic surface. The vibrational assignments of the Raman and SERS spectra were based on theoretical calculations obtained from density functional theory (DFT) of the isolated molecules or in interaction with metallic atoms. The DFT studies were made in collaboration with the Prof.Dr.Diego Paschoal from Universidade Federal do Rio de Janeiro and Prof.Dr Hélio Ferreira dos Santos from Universidade Federal de Juiz de Fora. The TEM images of K. pneumoniae and S.aureus bacteria obtained in the absence and in the presence of AgNP+QUIT were made in collaboration with the researcher Celso Sant’Ana and its student Mateus Eugênio from Instituto Nacional de Metrologia, Qualidade e Tecnologia. The cytotoxicity assays of the different combination of AgNP and chitosan and tetracycline against bovine fibroblast cells were made though colorimetric assay using MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The biological assay were made in collaboration with the Prof.Dr. Michele Munk and its students Leonara Fayer and Rafaella Zanetti from Universidade Federal de Juiz de Fora.

Using the solvent casting approach, a new composite hydrogel film based on ascorbic acid loaded carboxymethyl guar gum (CMG) and citric acid (CA) was produced for food packaging applications. The addition of glycerol to the formulation increased the film's flexibility and mechanical strength. The films were tested for anti-oxidant and anti-microbial properties against Escherichia coli and Staphylococcus aureus using the DPPH+ assay. MTT assay was used to assess the film's cytotoxicity. FTIR, XRD, SEM, and TGA were used to perform structural, morphological, and thermal investigation on the film. The film's viscosity and mechanical strength were investigated. The film's fruit shelf life-enhancer qualities were also evaluated utilizing orange as a fruit sample.

Dissertação de mestrado em Biofísica e Bionanossistemas
Nas últimas décadas tem havido uma crescente solicitação na inovação e desenvolvimento de elétrodos/sensores biomédicos capazes de detetar sinais provenientes de tecidos vivos e convertê-los em sinais mensuráveis. Neste contexto tem havido uma grande quantidade de materiais a serem desenvolvidos e aplicados para o fabrico deste tipo de sensores. Dentro desses materiais, os materiais poliméricos funcionalizados com filmes finos intermetálicos de Ti-Me (Me=Al, Au, Ag e Cu) têm demonstrado um enorme potencial na obtenção de sensores com características muito especificas, tais como: boa elasticidade, manipulação fácil, baixo custo de produção e bom comportamento elétrico e mecânico. No entanto, têm surgido preocupações sobre o impacto que os nanomateriais e este novo conceito de sensor possam ter em sistemas biológicos, levando a questões sobre o tipo de repercussões podem ocorrer a longo prazo. Neste sentido, o trabalho efetuado durante esta dissertação teve como objetivo o estudo do impacto dos filmes finos de Ti-Me em fibroblastos e queratinócitos, procurando caracterizar a influência dos filmes no comportamento in vitro destas células. Na realização deste estudo foram produzidos filmes finos de Ti-Me por pulverização catódica em magnetrão não balanceado usando diferentes áreas de metal Me, sendo depois estudada a composição química dos filmes e o seu efeito sobre a viabilidade celular metabólica, indução de stress oxidativo, e capacidade inflamatória em fibroblastos e queratinócitos. Os resultados de composição química mostraram que houve a produção de filmes finos de Ti- Me com diferentes percentagens atómicas de Me e os estudos in vitro demonstram em alguns resultados um efeito tóxico principalmente dependente da percentagem atómica, mas também dependente do tempo de condicionamento e do Me. Apesar de terem sido observados alguns efeitos a nível da indução de stresse oxidativo e inflamação em alguns dos filmes de Ti-Me produzidos, é necessário realizar estudos in vitro mais detalhados e estudos in vivo de modo a ser possível retirar conclusões sobre a segurança da aplicação destes filmes na pele humana.
In recent decades there has been a growing demand for innovation and development of biomedical electrodes/sensors capable of detecting signals from living tissue and convert them into measurable signals. In this context, a great number of materials have been developed and applied for the manufacture of this type of sensors. Within these materials the polymeric materials functionalized with intermetallic thin films of Ti-Me (Me = Al, Au, Ag and Cu) have demonstrated a great potential to obtain sensors with very specific characteristics, such as: good elasticity, easy handling, low production cost and good electrical and mechanical behavior. However, concerns have arisen about the impact that nanomaterials and this new sensor concept may have on biological systems, leading to questions about the type of cellular interactions that can be triggered and the kind of long-term efects that may occur. Given that Ti-Me thin film sensors are designed to interact with the surface of the human skin, it is important to study the cytotoxic effects that they may have when applied to cells that are characteristic of this organ. In this sense, the objective of this work was to study the impact of Ti-Me thin films on the in vitro biological behavior of fibroblasts and keratinocytes. In this study, thin films of Ti-Me were produced by unbalanced magnetron sputtering using different areas of Me metal. The chemical composition of the films and their effect on metabolic cell viability, induction of oxidative stress, and inflammatory capacity in fibroblasts and keratinocytes was evaluated. The results of chemical composition showed that Ti-Me thin films were produced with different atomic percentages of Me. The in vitro studies demonstrated some cytotoxic effect, capacity to induce oxidative stress and inflammation, dependent on the atomic percentage, time of incubation and the nature of Me atom. Although potential cytotoxic effects have been observed in some of the produced Ti-Me films, more studies have to be performed in order to draw conclusions about the safety of the application of these films on human skin.

Mannans are highly water-soluble mannose heteropolymers produced by a number of organisms, including yeasts. Polyhydroxyalkanoates (PHAs) are aliphatic polyesters produced by numerous bacteria as a carbon and energy source, with interesting thermal and mechanical properties. The main objective of this thesis was to prepare different polymeric structures base on mannans and PHAs for use in the pharmaceutical and biomedical areas. Mannans were produced by Komagataella pastoris using glycerol as carbon source, extracted with a heat-alkali treatment and purified using dialysis. PHAs were produced by mixed cultures using fermented fruit pulp waste, extracted using chloroform or hypochlorite and purified in ethanol. A successful deproteinization and an unsuccessful phosphorylation procedure was performed in mannans. The results show a decrease in protein content of 69.49 ± 0.44 % and a decrease in phosphate content of 60.45 ± 1.23 %, respectively. Mannans were tested in normal fibroblasts, HCT116 and A2780 cell lines for their cytotoxicity, by MTS assay, and no cytotoxicity was discovered. They were then used to prepare gel structures, and gelled using di- and tri-valent cations of iron and copper at low temperature (4 ⁰C) and alkaline pH. Gel particles were obtained in the above conditions and tested for their stability in water. Particles made using tri-valent iron were found the most stable. Mannans were also used to produce films. Films were obtained from i) mannans in water dried at 30 ⁰C or freeze dried, ii) from the previously produced films (30 ⁰C) and then coated with iron, at neutral pH or followed by immersion in an alkaline solution and, iii) from gel beads dried at 30 ⁰C or freeze dried. Films were tested for cell adhesion in vitro using normal fibroblasts, but no positive results were found. PHAs with different HV ratios were used to produce films, pure and blended with mannans, using chloroform as solvent by a solvent casting method. The produced films were tested for cell adhesion in vitro, using fibroblasts and MCF7-GFP. Pure PHA films were deemed good matrices for this application with cells adherent to their surface, whereas blend matrices failed in this regard. Some pure PHA matrices were then tested for their cytotoxicity using MCF7-GFP, and with the exception of co-polymer PHBHV with HV content of 18 % (extracted with hypochlorite), they were found to be non-cytotoxic, rendering them useful for biomedical applications such as wound dressing or drug delivery.

Multifunctional biomedical materials capable of integrating optical functions open up promising new possibilities for the application of photosensitive materials. For example, they are highly desirable for advanced intraocular lens (IOL) implants. For this purpose, we propose hydrogels, based on poly(ethylene glycol) (PEG) prepolymers, which are photochemically crosslinkable and thereby patternable. Various photoinitiators are used and investigated spectroscopically; those with high sensitivity in the optical region of the spectrum are advantageous. Hydrogel films have been obtained, which are applicable for light-based patterning and, hence, for functionalization of both surface and volume: It is shown that a local change in optical properties can be induced in special hydrogel films by photochemical crosslinking. Such a local light-induced material response forms the basis for volume holographic patterning. Cytocompatibility of hydrogels and compositions is evaluated via cytotoxicity tests. Exploiting the interrelationship between structure and function is highly relevant for biomedical materials with multifunctionality.

The material selected for biomedical application must be biocompatible, stable against physiological media, non-toxic, non-carcinogenic, corrosion-resistant, bio-inert, and stimuli-responsive, and have a low wear rate. Lignin is the most abundant aromatic polymer on Earth with a complex, recalcitrant structure. A lot of knowledge is acquired on its pre-treatments and processing for biomedical uses in the forms of hydrogels, films, composite materials, nanoparticles, and aerogels. To avoid the potential toxicity and to control the cytotoxicity of lignin-based materials, it is necessary to increase the purity of the starting source materials and understand their reactivity. The poor water solubility, broad molecular weight (MW) distribution, and highly complex structure of lignin restrict its wider clinical applications. These limitations may be effectively improved by chemical modifications or by using lignin fractions with a narrow MW range. Antioxidant and antimicrobial properties allow lignin to be used in pharmaceuticals, drug delivery, and wound healing. It is also reported as a good candidate for composite materials intended for bone regeneration scaffolds in tissue engineering. Future challenges for lignin-based materials for biomedical applications include achieving a better understanding of the structure, isolation, and batch properties of lignin, as well as structure–function relationships in its applications.

Hydroxyapatite (HA)-magnesium (Mg) composite thin films were grown on magnesium substrates using a multitarget pulsed laser deposition technique. The microstructural and corrosion properties of HA-Mg composite thin films were investigated using methods such as x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis, and potentiodynamic polarization. While the XRD studies have indicated the amorphous nature of the HA-Mg composite coating, SEM and EDX studies have shown that the composite films are stoichiometric. The potentiodynamic polarization study indicates that the corrosion of magnesium decreases with increase in the hydroxyapatite content in the composite film. The corrosion potential (Ecorr) and corrosion current density (Icorr) for the uncoated magnesium, 30HA-70Mg, and 50HA-50Mg coated magnesium are −1.59, −1.57, −1.54 V and 1.21×10−5, 1.38×10−6, 2.52×10−7 A/cm2, respectively. Preliminary cytotoxicity test conducted on the samples shows no adverse effect on human bone marrow stromal cells. The advantage of the composite coatings is the realization of adjustable corrosion and biological properties by a simple maneuvering of composition which in turn is realized by changing the number of laser pulses on a respective target.