Gabriel Molina de Olyveira

Bacterial Nanocellulose for Medical Implants

Bacterial cellulose (BC) has established to be a remarkably versatile biomaterial and can be used in wide variety of applied scientific endeavours, especially for medical devices. In fact, biomedical devices recently have gained a significant amount of attention because of an increased interest in tissue-engineered products for both wound care and the regeneration of damaged or diseased organs. Due to its unique nanostructure and properties, microbial cellulose is a natural candidate for numerous medical and tissue-engineered applications. Hydrophilic bacterial cellulose fibers of an average diameter of 50 nm are produced by the bacterium Acetobacter xylinum, using a fermentation process. The microbial cellulose fiber has a high degree of crystallinity. Using direct nanomechanical measurement, determined that these fibers are very strong and when used in combination with other biocompatible materials, produce nanocomposites particularly suitable for use in human and veterinary medicine. Moreover, the nanostructure and morphological similarities with collagen make BC attractive for cell immobilization and cell support. The architecture of BC materials can be engineered over length scales ranging from nano to macro by controlling the biofabrication process. The chapter describes the fundamentals, purification and morphological investigation of bacterial cellulose. This chapter deals with the modification of microbial cellulose and how to increase the compatibility between cellulosic surfaces and a variety of plastic materials. Furthermore, provides deep knowledge of fascinating current and future applications of bacterial cellulose and their nanocomposites especially in the medical field, materials with properties closely mimic that of biological organs and tissues were described.

Bacterial Nanocellulose for Medicine Regenerative

Bacterial cellulose (BC) has established to be a remarkably versatile biomaterial and can be used in a wide variety of applied scientific endeavours, especially for medical devices. Nanocellulose, such as that produced by the bacteria Gluconacetobacter xylinus (bacterial cellulose, BC), is an emerging biomaterial with great potential in flexible radar absorbing materials, in scaffold for tissue regeneration, water treatment, and medical applications. Bacterial cellulose nanofibril bundles have excellent intrinsic properties due to their high crystallinity, which is higher than that generally recorded for macroscale natural fibers and is of the same order as the elastic modulus of glass fibers. Compared with cellulose from plants, BC also possesses higher water holding capacity, higher degree of polymerization (up to 8000), and a finer weblike network. In addition, BC is produced as a highly hydrated and relatively pure cellulose membrane, and therefore no chemical treatments are needed to remove lignin and hemicelluloses, as is the case for plant cellulose. Because of these characteristics, biomedical devices recently have gained a significant amount of attention because of an increased interest in tissue-engineered products for both wound care and the regeneration of damaged or diseased organs. Hydrophilic bacterial cellulose fibers of an average diameter of 50 nm are produced by the bacterium Acetobacter xylinum, using a fermentation process. The architecture of BC materials can be engineered over length scales ranging from nano to macro by controlling the biofabrication process. Moreover, the nanostructure and morphological similarities with collagen make BC attractive for cell immobilization and cell support. This review describes the fundamentals, purification, and morphological investigation of bacterial cellulose. Besides, microbial cellulose modification and how to increase the compatibility between cellulosic surfaces and a variety of plastic materials have been reported. Furthermore, provides deep knowledge of current and future applications of bacterial cellulose and their nanocomposites especially in the medical field.

Biofuel Cells: Bioelectrochemistry Applied to the Generation of Green Electricity

Several studies published in the last decade have pointed to the use of enzymes and microorganisms in biocatalytic reactions to generate electricity. Enzymes and living organisms can be used in modified electrodes to build the so-called biofuel cells (BFCs). However, a deep understanding of the structure and biocatalytic properties after enzyme immobilization is still lacking because they are immobilized in the solid state and outside of their natural environment. Thus, based on biological molecules and nanostructure materials applied to BFCs, these current topics shall be reviewed here, and prospects for future development in these areas will be presented as well. Moreover, immobilization methodologies and enzyme stability systems that result in BFCs will also be presented. Finally, BFC power density and catalyst support will be widely discussed in this book chapter.

Special Nanoskin-ACT-Biological Membranes from Deep Wounds

Bacterial cellulose (BC) is established as a newest biomaterial, and it can be used for medical and odontology applications. In addition, it has called attention for uses such as membrane for wound care and tissue engineering. In this work, the bacterial cellulose fermentation process is modified by the addition of natural materials before the bacteria are inoculated. In vivo behavior using natural ECM for regenerative medicine is presented and completed wound healing process is 3 months.

Nanoskin: uso para reposição de volume na cavidade anoftálmica

Objetivo: Avaliar a biocompatibilidade da Nanoskin para reposicao de volume em cavidades enucleadas ou evisceradas de coelhos. Metodos: Estudo experimental, utilizando implantes de Nanoskin (Innovatecs®, Sao Carlos, Brasil), celulose bacteriana produzida pela bacteria Acetobacter xylinum tendo como substrato o cha-verde. Implantes de 10mm de diâmetro/5mm de espessura foram colocados em cavidades enucleadas (G1) ou evisceradas (G2) de 21 coelhos, avaliados clinicamente todos os dias, sacrificados aos 7, 30 e 90 dias apos a cirurgia. O material foi removido e preparado para exame de microscopia optica. Resultados: Sinais flogisticos discretos no posoperatorio imediato, nao tendo sido evidenciados sinais infecciosos ou extrusao de nenhum implante. Houve aparente reducao do volume ao longo do periodo experimental. Histologicamente ambos os grupos foram muito semelhantes, apresentando aos 7 dias celulas inflamatorias (predominantemente monocitos e neutrofilos), rede de fibrina e hemacias. A Nanoskin apresentava-se como pequenas esferas, de cor rosea, com pequenos espacos entre elas, permeados por escassas celulas inflamatorias. As celulas inflamatorias se modificaram ao longo de periodo experimental, sendo possivel observar aos 30 dias celulas gigantes multinucleadas e fibroblastos maduros permeando o implante. Aos 90 dias, a estrutura do implante apresentava-se desorganizada, amorfa, com restos necroticos e com areas ovoides, revestidas por fina membrana rosea, que pareciam se agrupar, vazias ou preenchidas por material acelular, roseo ou acinzentado. Conclusao: A Nanoskin provocou reacao inflamatoria que levou a reabsorcao e reducao do volume do implante. Novas formulacoes devem ser estudadas a fim de ter um produto que seja permanente para reparo da cavidade anoftalmica.

CHAPTER 9:Protein-based Polymer Nanocomposites for Regenerative Medicine

Nature-inspired routes involving the creation of natural origin polymer-based systems constitute an alternative route to produce novel natural nanocomposites. Composition in these systems can be designed to mimic the tissue environment required for cellular regeneration of soft and hard tissues. Factors such as design, choice, compatibility of the polymers, their degradability, low cost and intrinsic cellular interaction makes them very attractive candidates for regenerative medicine. The present chapter overviews the potential applications of natural origin polymer-based systems, especially those investigated from protein-based polymer systems, and proposed for the treatment of soft and hard tissues. Emphasis is made on the structural modifications, properties and compatibility of the natural materials and their nanocomposites for regenerative medicine.