Laser-Treated Surfaces for VADs: From Inert Titanium to Potential Biofunctional Materials

Laser-treated surfaces for ventricular assist devices. Impact Statement. This work has scientific impact since it proposes a biofunctional surface created with laser processing in bioinert titanium. Introduction. Cardiovascular diseases are the world’s leading cause of death. An especially debilitating heart disease is congestive heart failure. Among the possible therapies, heart transplantation and mechanical circulatory assistance are the main treatments for its severe form at a more advanced stage. The development of biomaterials for ventricular assist devices is still being carried out. Although polished titanium is currently employed in several devices, its performance could be improved by enhancing the bioactivity of its surface. Methods. Aiming to improve the titanium without using coatings that can be detached, this work presents the formation of laser-induced periodic surface structures with a topology suitable for cell adhesion and neointimal tissue formation. The surface was modified by femtosecond laser ablation and cell adhesion was evaluated in vitro by using fibroblast cells. Results. The results indicate the formation of the desired topology, since the cells showed the appropriate adhesion compared to the control group. Scanning electron microscopy showed several positive characteristics in the cells shape and their surface distribution. The in vitro results obtained with different topologies point that the proposed LIPSS would provide enhanced cell adhesion and proliferation. Conclusion. The laser processes studied can create new interactions in biomaterials already known and improve the performance of biomaterials for use in ventricular assist devices

Recobrimento de scaffolds biocerâmicos com nanopartículas de ação antibacteriana

Uma importante área da Engenharia de materiais é o desenvolvimento de biomateriais aplicados a área da saúde. Um biomaterial que vem sendo muito estudado é o scaffolds, estrutura tridimensional semelhante ao tecido ósseo natural, cuja função é auxiliar esse tecido a se regenerar em caso de fraturas. O interesse na área se dá principalmente pela grande quantidade de casos de fraturas ósseas causadas por acidentes e fraturas patológicas como a osteoporose. O desenvolvimento dos scaffolds tem sido focado não apenas no reparo das fraturas, mas também em problemas associados a infecções causadas por agentes infecciosos ao tecido ósseo, que são recorrentes, seja por contato direto ou pela corrente sanguínea, como a osteomielite. Estudou-se scaffolds de vitrocerâmicas derivados de biovidro 45S5 e de cimento de wollastonita com 1% de NCC, ambos, com boas propriedades de interação com os tecidos vivos, como já relatados na literatura, recobertos com NPs de propriedades antibacterianas. O objetivo foi obter um scaffold promissor para recuperação de tecidos ósseos, sendo biocompatível, bioativo e biodegradável, favorecendo a regeneração do tecido e evitando doenças infecciosas como a osteomielite. As NPs foram estudadas quanto à biocompatibilidade, bioatividade e ação antimicrobiana. Os scaffolds de vitrocerâmicas foram produzidos pelo método de gelcasting e impressão 3D, os scaffolds de cimento de wollastonita por sol-gel e foram caracterizados por DRX, MEV, densidade, porosidade, bioatividade e ação antimicrobiana. Os scaffolds de vitrocerâmicas foram citotóxicos para o crescimento celular, porém demonstraram excelente atividade antimicrobiana. As CuO B NPs, apresentaram boa inibição no crescimento de bactérias e foram selecionadas para recobrir o scaffold de cimento de wollastonita que inicialmente apresentou inibição do crescimento celular, porém, após um período de 4 dias às células começaram a se aderir e crescer no material. Esse resultado é interessante para a aplicação do material em regeneração tecidual, pois indica que nos primeiros dias em contato com o meio biológico pode haver a inibição de crescimento de E. coli e S. aureus, o que evitaria complicações pós-cirúrgicas, e em seguida, seria iniciada a fase de regeneração do tecido.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Laser-Treated Surfaces for VADs: From Inert Titanium to Potential Biofunctional Materials

Objective. Laser-treated surfaces for ventricular assist devices. Impact Statement. This work has scientific impact since it proposes a biofunctional surface created with laser processing in bioinert titanium. Introduction. Cardiovascular diseases are the world’s leading cause of death. An especially debilitating heart disease is congestive heart failure. Among the possible therapies, heart transplantation and mechanical circulatory assistance are the main treatments for its severe form at a more advanced stage. The development of biomaterials for ventricular assist devices is still being carried out. Although polished titanium is currently employed in several devices, its performance could be improved by enhancing the bioactivity of its surface. Methods. Aiming to improve the titanium without using coatings that can be detached, this work presents the formation of laser-induced periodic surface structures with a topology suitable for cell adhesion and neointimal tissue formation. The surface was modified by femtosecond laser ablation and cell adhesion was evaluated in vitro by using fibroblast cells. Results. The results indicate the formation of the desired topology, since the cells showed the appropriate adhesion compared to the control group. Scanning electron microscopy showed several positive characteristics in the cells shape and their surface distribution. The in vitro results obtained with different topologies point that the proposed LIPSS would provide enhanced cell adhesion and proliferation. Conclusion. The laser processes studied can create new interactions in biomaterials already known and improve the performance of biomaterials for use in ventricular assist devices

Bionanomining of copper-based nanoparticles using pre-processed mine tailings as the precursor

The bacterial synthesis of copper nanoparticles emerges as an eco-friendly alternative to conventional techniques since it comprises a single-step and bottom-up approach, which leads to stable metal nanoparticles. In this paper, we studied the biosynthesis of Cu-based nanoparticles by Rhodococcus erythropolis ATCC4277 using a preprocessed mining tailing as a precursor. The influence of pulp density and stirring rate on particle size was evaluated using a factor-at-time experimental design. The experiments were carried out in a stirred tank bioreactor for 24 h at 25 ◦C, wherein 5% (v/v) of bacterial inoculum was employed. The O2 flow rate was maintained at 1.0 L min-1 and the pH at 7.0. Copper nanoparticles (CuNPs), with an average hydrodynamic diameter of 21 ± 1 nm, were synthesized using 25 g.L-1 of mining tailing and a stirring rate of 250 rpm. Aiming to visualize some possible biomedical applications of the as-synthesized CuNPs, their antibacterial activity was evaluated against Escherichia coli and their cytotoxicity was evaluated against Murine Embryonic Fibroblast (MEF) cells. The 7-day extract of CuNPs at 0.1 mg mL-1 resulted in 75% of MEF cell viability. In the direct method, the suspension of CuNPs at 0.1 mg mL-1 resulted in 70% of MEF cell viability. Moreover, the CuNPs at 0.1 mg mL-1 inhibited 60% of E. coli growth. Furthermore, the NPs were evaluated regarding their photocatalytic activity by monitoring the oxidation of methylene blue (MB) dye. The CuNPs synthesized showed rapid oxidation of MB dye, with the degradation of approximately 65% of dye content in 4 h. These results show that the biosynthesis of CuNPs by R. erythropolis using pre-processed mine tailing can be a suitable method to obtain CuNPs from environmental and economical perspectives, resulting in NPs useful for biomedical and photocatalytic applications.São Paulo Research Foundation (FAPESP) [grant number #2019/07659-4]São Paulo Research Foundation (FAPESP) project number 2019/ 19144-9Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES), Finance Code 00