Meniscus is a wedge shaped structure, with a convex base attached to a flat tibial surface, and with a concave femoral surface, on which femur and tibia articulate. It has several functions including joint lubrication, shock absorption, load transmission and joint stability. Various methods were tried to treat meniscal tears but each has its own drawbacks. Tissue engineering seems to be a promising solution that avoids all the problems associated with the other approaches. In this study, a three dimensional (3D) collagen-based structure was prepared by tissue engineering to mimic the natural human meniscus. Three different foams prepared under different conditions were combined and nano/microfibrous layers were placed in between them. To mimic the properties of the natural tissue, the top layer was composed of collagen-chondroitin sulfate-hyaluronic acid (Coll-CS-HA) prepared by freezing at -20&ordm / C followed by lyophilization. The middle and bottom layers were made with just collagen after freezing at -20&ordm / C and -80&ordm / C, respectively and lyophilization. Aligned nano/microfibers were prepared using collagen-poly(L-lactic-co-glycolic acid (Coll-PLGA). Various crosslinking procedures such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS), genipin (GP), glutaraldehyde (GLU) either alone or in combination with dehydrothermal treatment (DHT) were used and based on both compressive and tensile properties, the best crosslinker was chosen to be DHT+EDC/NHS. Mechanical properties (compressive, tensile and shear) of the dry foams and the final 3D construct were evaluated. The highest mechanical properties were obtained with the 3D construct. Then all these foams and the 3D construct were seeded with human fibrochondrocytes to study the cell behavior such as attachment, proliferation, and extracellular matrix (ECM) and glucosaminoglycan (GAG) production. Furthermore, the influence of cell seeding on the compressive properties of wet individual foams and the 3D construct was observed. As expected, the highest cell proliferation and compressive properties were obtained with the 3D construct. Finally, the 3D constructs, seeded with fibrochondrocytes, were implanted in New Zealand rabbits after meniscectomy. The initial microscopical examination show that the 3D construct has a significant potential as a meniscus substitute.

Disruption of the skin generally leads to an increased fluid loss, infection, hypothermia, scarring, compromised immunity and change in body image; furthermore, large skin damage can cause mortality. Collagen-based film is a potentially useful biomaterial since it is the major constituent of the connective tissue and permit controlled drug release within target tissues. Usnic acid (UA), a dibenzofuran originally isolated from lichens, it can act as an anti-inflammatory, analgesic and antibacterial agent. The purpose of this study was to evaluate the physical-chemical properties and effect of collagen-based films containing usnic acid as a wound dressing for dermal burn healing. Collagen (CL) and usnic acid/collagen-based (UAC) films were characterized using differential thermal analysis (DTA), thermogravimetry (TG/DTG), infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Second-degree burn wounds of 1 cm2 were performed in the dorsum of forty-five Wistar rats, assigned into nine groups (n=5): COL animals treated with collagen-based films; PHO animals treated with collagen films containing empty liposomes; UAL animals treated with collagen-based films containing usnic acid incorporated into liposomes. After 7, 14 and 21 days the animals were euthanized. The specimens removed were formalin-fixed, and paraffin-embedded and histological sections were stained in HE and Sirius Red. In the spectrum of UAC, similar bands of the usnic acid are observed, indicating that the polymerization (film formation) did not affect the stability of the drug. Distinctly, DTA curve of UAC did not show an endothermic peak at 201ºC, indicative that the drug was incorporated into the polymeric system. These results were corroborated by the scanning electron microscopy (SEM). The TG/DTG curves of UAC presented a different thermal decomposition profile compared to the individual compounds and CL. These findings suggest the occurrence of molecular dispersion or solubilization of the drug in the collagen film. The specificity revealed that the excipients in the formulation did not interfere with the analysis. The linearity in the range of 2-10 μg/mL presented a correlation coefficient of 0.9994. The method showed excellent repeatability (R.S.D. < 1.0 %). The accuracy, revealed a mean percentage recovery of 100.43 %. The method was robust for the variation of temperature and solvent. The detection and quantization limits were found 0.109 and 0.364 μg/mL. The total rate recovery of the analyte film showed values between 100.4 and 83.2%. Biologycal assays showed on 7th day there was a moderate infiltration of neutrophils, in UAL, distributed throughout the burn wounds, whereas in COL and PHO, the severity of the reaction was slighter and still limited to the margins of the burn wounds. On the 14th day, the inflammatory reaction was less intense in UAL, with remarkable plasma cells infiltratation. On the 21st day, there was unequivocal reduction of the inflammation, which was predominantly composed of plasma cells in all groups, particularly in UAL. The use of collagen-based films containing usnic acid provided more rapid substitution of type-III for type-I collagen on the 14th day, and improved the collagenization density on the 21st day. It was concluded that the use of reconstituted bovine type-I collagen-based films containing usnic acid improved burn healing process in rats. / Há diversos produtos disponíveis para o tratamento de feridas provocadas principalmente por queimaduras tais como, agentes tópicos, soluções, enxertos, curativos interativos e filmes bioativos. O colágeno têm sido um dos materiais mais estudados, pois representa um importante constituinte protéico da pele. Os avanços científico-tecnológicos têm permitido o aprimoramento destes biomateriais através, por exemplo, da utilização de lipossomas, que possibilitam a incorporação de fármacos insolúveis para posterior liberação controlada diretamente na área lesada. O ácido úsnico (AU), um metabólito secundário de líquens, tem apresentado propriedades biológicas promissoras para o tratamento de feridas, como atividade antimicrobiana, analgésica e antiinflamatória. Nesta perspectiva, o objetivo desse estudo foi desenvolver, caracterizar físico-quimicamente e avaliar o efeito de filmes de colágeno contendo AU sobre o processo de reparo cicatricial em queimaduras de segundo grau. Para a caracterização físico-química dos filmes foi utilizada a análise térmica diferencial (DTA), termogravimetria (TG/DTG), espectroscopia no infravermelho (FTIR) e microscopia eletrônica de varredura (MEV). Após essas análises, foi desenvolvida a validação do método de quantificação de AU nos filmes por espectrofotometria no ultravioleta. Por fim, o ensaio biológico foi realizado com 54 ratos divididos em três grupos: tratados com filme de colágeno (COL); tratados com filmes de colágeno contendo fosfolipídio (LIP); tratados com filmes de colágeno contendo lipossoma/ácido úsnico (AUL). Após 7, 14 e 21 dias seis animais de cada grupo foram submetidos à eutanasia para análise histológica e imunohistoquímica. Os resultados de análise térmica mostraram através da curva DTA do filme UAL a ausência do pico endotérmico à 201ºC, característico da fusão do AU puro, indicando que o fármaco foi incorporado ao sistema polimérico. Estes resultados foram confirmados pelo MEV. As curvas TG/DTG dos filmes LIP e AUL apresentaram comportamento térmico diferente do AU livre. No espectro de IV do filme AUL foram observadas bandas similares ao AU livre, indicando que a incorporação não afetou a estabilidade do mesmo. A validação do método de doseamento apresentou um coeficiente de correlação de 0,9994 e excelente repetibilidade (C.V.< 1,0%). A exatidão apresentou média percentual de recuperação de 100,4%. Os valores dos limites de detecção e quantificação foram de 0,109 e 0,364 μg/mL, respectivamente. A taxa total de recuperação do analito nos filmes apresentou valores entre 100,4 e 82,3%. Os resultados do ensaio biológico aos 7 dias, mostraram que houve uma moderada infiltração neutrofílica, no filme AUL, distribuídos por toda a lesão, enquanto que no COL e LIP, a intensidade da reação inflamatória foi mais leve e limitada as margens da ferida. Aos 14 dias, a reação inflamatória foi reduzida em todos os grupos, no entanto, a reação de granulação foi mais desenvolvida no AUL. Aos 21 dias, observou a presença ainda expressiva de linfócitos nos grupos COL e LIP, enquanto que no AUL houve o predomínio de células plasmáticas. O uso dos filmes de colágeno contendo lipossomas/ácido úsnico (AUL), atuou desde a substituição mais rápida das fibras de colágeno tipo III para tipo I, até a melhora na densidade da colagenização. Conclui-se assim, que os filmes de colágeno contendo lipossomas/ácido úsnico promovem a aceleração dos eventos biológicos associados à dinâmica do reparo cicatricial.

Cardiovascular disease (CVD) is ranked the second leading cause of death in Canada, with 53,704 heart disease-related deaths documented in 2020 alone. After a patient sustains cardiac injury, such as a myocardial infarction (MI), the heart is often unable to undergo sufficient self-recovery for healthy cardiac regeneration and repair; this is largely attributed to fibrotic tissue development at the injury site and subsequent pathological ventricular remodeling. The prevalence of MI events has created a considerable demand to develop novel strategies for effective and safe post-MI therapies. Research has indicated that post-MI modifications interfere with endogenous cardiac repair mechanisms, resulting in a pathological state. After an infarction, there is an accumulation of methylglyoxal (MG) at the site of injury. It has been suggested that MG contributes to ventricular fibrotic development, however its underlying mechanism remains unclear. Additionally, the effects that the post-MI cardiac environment, specifically MG accumulation, has on post-MI therapies and biomaterials has not been sufficiently established. Accordingly, the primary focus of this research project is to elucidate the effects of MG on the collagen-rich extracellular matrix (ECM) of the heart and key cardiac cells involved in the repair process. Further, the interaction between MG and a promising collagen-based hydrogel therapy is investigated, exploring the effects of MG on the hydrogel’s degradative process. It was found that the MG modification of hydrogels did not alter the degradation rate. Additionally, the degradation products of hydrogels, and MG-modified substrates did not affect the properties and formation of myofibroblasts.

The development of vascular replacement for low flow rates is a topical issue. The model for developing the development of replacement properties, which are based on the idea of assuming the characteristics of the biological model - vena saphena and programming these properties into a model of constructed replacement is one of the possible directions of development. The presented replacement, which is the result of the work of the author's team, consists of three parts - a non-absorbable scaffold representing the media, and two absorbable collagen layers - pseudointima and pseudoadventice. Target parameters of the prosthesis were determined by test results of the basic physical testing method - uniaxial tensile test and inflation-extension test, as well as other procedures in human saphenous specimens. The key issue is the technology of producing the collagen layer of the prosthesis. However, other manufacturing processes can also have a significant impact on vascular prosthesis properties, such as collagen hardening, antithrombogenic treatment of the inner surface of the vascular replacement, and the use of a sterilization method. Furthermore, the author deals with the development of a new female component of the three- layer vascular prosthesis of the Czech carp, which is characterized by lower...