High Dispersivity Bacterial Cellulose/Carbon Nanotube Nanocomposite for Sensor Applications

Bacterial cellulose (BC) has established to be a remarkably versatile biomaterial and can be used in wide variety of applied scientific endeavors, especially for medical devices. In fact, biomedical devices recently have gained a significant amount of attention because of increased interesting tissue-engineered products for both wound care and the regeneration of damaged or diseased organs. The architecture of BC materials can be engineered over length scales ranging from nano to macro by controlling the biofabrication process, besides, surface modifications bring a vital role in in vivo performance of biomaterials. In this work, bacterial cellulose fermentation was modified with carbon nanotubes for sensor applications and diseases diagnostic. SEM images showed that polymer modified-carbon nanotube (PVOH-carbon nanotube) produced well dispersed system and without agglomeration. Influences of carbon nanotube in bacterial cellulose were analyzed by FTIR. TGA showed higher thermal properties of developed bionanocomposites.

Novel Antimicrobial Peptides Bacterial Cellulose Obtained by Symbioses Culture Between Polyhexanide Biguanide (PHMB) and Green Tea

Bacterial cellulose is a highly hydrated pellicle made up of a random assembly of ribbon shaped fibers less than 5 nm wide. The unique properties provided by the nanometric structure have led to a number of diagnostic biological probes, display devices due to their unique size-dependent medical applications. Bacterial cellulose matrix extracellular is a novel biotechnology and unique medicine indicated for ultimate chronic wound treatment management, drug delivery, tissue engineering, skin cancer and offers an actual and effective solution to a serious medical and social problem and to promote rapid healing in lesions caused by Diabetic burns, ulcers of the lower limbs or any other circumstance in which there's epidermal or dermal loss. In this work, it is reported novel antimicrobial peptides (AMPs) bacterial cellulose/polyhexanide biguanide (PHMB) which are produced by symbioses culture between polyhexanide biguanide and green tea culture medium resulting in the pure 3-D structure consisting of an ultra-fine network of novel biocellulose/PHMB nanofibres matrix (2-8 nm), highly hydrated (99% in weight), and with higher molecular weight, full biocompatibility.

Novel Chemically Modified Bacterial Cellulose Nanocomposite as Potential Biomaterial for Stem Cell Therapy Applications

Bacterial cellulose (BC) has become established as a remarkably versatile biomaterial and can be used in a wide variety of applied scientific applications, especially for medical devices. In this work, the bacterial cellulose fermentation process is modified by the addition of hyaluronic acid and gelatin (1% w/w) to the culture medium before the bacteria is inoculated. Hyaluronic acid and gelatin influence in bacterial cellulose was analyzed using Transmission Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adhesion and viability studies with human dental pulp stem cells using natural bacterial cellulose/hyaluronic acid as scaffolds for regenerative medicine are presented for the first time in this work. MTT viability assays show higher cell adhesion in bacterial cellulose/gelatin and bacterial cellulose/ hyaluronic acid scaffolds over time with differences due to fiber agglomeration in bacterial cellulose/gelatin. Confocal microscopy images showed that the cell were adhered and well distributed within the fibers in both types of scaffolds.

Bacterial cellulose as a template for preparation of hydrotalcite-like compounds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção e imobilização de celulases em matriz de agarose com diferentes ativações químicas

Pós-graduação em Biotecnologia - IQ

Thermo-sensitive chitosan-cellulose derivative hydrogels: swelling behaviour and morphologic studies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermal behavior of Ca2+ and Cu2+ oxalates obtained by precipitation in homogeneous solution from dimethyl oxalate hydrolysis

Mixed calcium and copper oxalates, with different proportions of Ca2+ and Cu2+ ions, were precipitated by dimethyl oxalate hydrolysis in homogeneous solution. The compounds were evaluated by means of scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetry (TG), and differential thermal analysis (DTA). The results suggested quantitative precipitation without solid solution formation. From the TG and DTA curves, it was possible to evaluate the Ca2+ ion proportion in the solid phase and to confirm the precipitation of the individual species.

Preparation, thermal characterization, and DFT study of the bacterial cellulose

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bacterial Cellulose Nanobiocomposites for Dental Materials Scaffolds

Bacterial cellulose (BC) has become established as a remarkably versatile biomaterial and can be used in a wide variety of scientific applications, especially for medical devices. In this work, the bacterial cellulose fermentation process is modified by the addition of chondroitin sulfate and hyaluronic acid (1% w/w) to the culture medium before the bacteria is inoculated. Besides, biomimetic precipitation of calcium phosphate of biological interest from simulated body fluid on bacterial cellulose was studied. Chondroitin sulfate and hyaluronic acid effects in bacterial cellulose were analyzed using transmission infrared spectroscopy (FTIR), XRD (X-ray diffraction) and scanning electron microscopy (SEM). FTIR analysis showed interaction between bacterial cellulose nanobiocomposites and calcium phosphate. XRD demonstrated amorphous calcium phosphate, carbonated apatite and calcium chloride on bacterial cellulose nanobiocomposites. Monocalcium phosphate monohydrate phase formation [Ca(H2PO4)(2)center dot H2O] are here attested by FTIR, XRD and Ca/P relation.

ESI(+)-MS and GC-MS Study of the Hydrolysis of N-Azobenzyl Derivatives of Chitosan

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação do efeito da temperatura na deslignificação com o oxigênio nas propriedades do papel

The deslignification with oxygen, also denominated pre-O2, consists in a whitening stage, which consists of accomplishing an oxidation of the lignin, and remove it with the alkali, providing a larger earnings in the bleaching of the pulp. The pre-O2 is a process already very established, where a significant part of the cellulose of whitened short fiber produced nowadays suffers deslignification for this method. The conditions of work of this stage contemplate directly in the results of the deslignification level, in the physical, optical and mechanics properties of the pulp, and consequently of the paper, because this is important to know their effects fully. The main variables related to the control of this process are respectively: pressure and oxygen load, alkaline load, consistence, time and temperature, being this last variable was the study focus in this work. The objective of the work was to analyze the effect of the variation of the temperature in the oxygen whitening along every bleaching process of the pulp, refine and in the optical, physics and mechanics properties of the paper. The development of the work was based in four temperature levels (90, 95, 100 and 105°C) combined to two whitening sequences (OD0(E+P)D1P and OAHTD0(E+P)D1P). The results obtained in the oxygen deslignification stage indicated that the elevation of the temperature contemplated in increases of the whiteness, deslignification efficiency and in the viscosity loss allied to the reduction of the selectivity of the process. In the remaining of the whitening, the sequence that included the acid hydrolysis presented values slightly inferior of whiteness, kappa number, viscosity and yield in relation to the other sequence when compared with the samples of same temperatures. Already the physical tests showed that the sequence with acid stage amplifies the values of capillary... (Complete abstract click electronic access below)

Estudo do potencial enzimático hidrolítico e oxidativo do microorganismo Myceliophthora thermophila M.7.7

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Stability of a Lipase Extracted from Seeds of Pachira aquatica in Commercial Detergents and Application Tests in Poultry Wastewater Pretreatment and Fat Particle Hydrolysis

A protein extract containing a plant lipase from oleaginous seeds of Pachira aquatica was tested using soybean oil, wastewater from a poultry processing plant, and beef fat particles as substrate. The hydrolysis experiments were carried out at a temperature of 40°C, an incubation time of 90 minutes, and pH 8.0-9.0. The enzyme had the best stability at pH 9.0 and showed good stability in the alkaline range. It was found that P. aquatica lipase was stable in the presence of some commercial laundry detergent formulations, and it retained full activity up to 0.35% in hydrogen peroxide, despite losing activity at higher concentrations. Concerning wastewater, the lipase increased free fatty acids release by 7.4 times and promoted the hydrolysis of approximately 10% of the fats, suggesting that it could be included in a pretreatment stage, especially for vegetable oil degradation.