Titanium is used in orthopedic and orthodontic implants because it has good corrosion resistance and excellent biocompatibility. Thus, studies seek to obtain a coating to improve the adhesion between the bone and the implant, by modifying the metal’s surface. The objective of this work was to biomimetically coat C.P. Ti with hydroxyapatite doped with silver nitrate, a component with antimicrobial properties, coating the metallic-ceramic composite with a polycaprolactone polymer film, which is known by generate improved implant-tissue interaction, and reducing postoperative complications from bacterial infections. The characterization of the material demonstrated the existence of the coating overall surface of the metallic substrate. The results obtained from the bacterial culture tests with Staphylococcus aureus showed that nitrate was effective in reducing the amount of live bacteria present in the supernatant, as well as those adhered to the surface of the material. In addition, the polymeric coating did not prevent the release of the bactericidal agent, not interfering in the effect there.

In this paper, a novel wound dressing membrane for controlled release of gentamicin (GE), while covering and protecting the wound was investigated. Chitosan (CHI) was associated with methoxy polyethylene glycol - polycaprolactone copolymer (mPEG-PCL) to prepare the blended wound dressing membranes. The use of copolymer mPEG-PCL was necessary to improve the compatibility between CHI and PCL. The association of CHI and PCL was required to control the water retention and release rate of encapsulated GE. In vitro release studies were performed with the mPEG-PCL/CHI-GE membranes in order to evaluate the effect of copolymer concentration on the kinetics of GE release and water uptake. Reduced burst release rates and swelling ratios were observed for the 1/2 and 1/4 mPEG-PCL/CHI-GE membranes. In addition, all gentamicin-loaded membranes inhibited S. aureus and E. coli growth, and demonstrated color, moisture and thermal stability. Therefore, mPEG-PCL/CHI-GE membranes showed important features for potential wound dressing and drug delivery applications.

Heart diseases affect part of world population and generally involves the functioning of valves. Valves replacement is the most common treatment and the choice between synthetic or natural/biological implants depends on several factors. Synthetic implants have greater durability, whereas biological ones are more biocompatible. This work proposes the use of polymeric coating on titanium metal surface to increase implant biocompatibility. Poly-caprolactone (PCL) has demonstrated greater efficacy for biomedical applications due to its biocompatibility. It can easily form films and coat surfaces. Titanium discs were submitted to alkaline and thermal treatments and coated with 1%PCL and 1%PCL+TiO2. For both conditions, PCL crystals were found in titanium coated surface (SEM and EDX) and X-ray diffractogram confirmed PCL coating. Infrared Spectroscopy spectra showed both PCL and TiO2 characteristic peaks. Moreover, corrosion resistance of coated disc has considerably increased, proving the effectiveness of PCL as coating material and its potential application in cardiac valves.

A biocompatible and biodegradable hybrid chitosan/glycerol phosphate hydrogel (CS-GP) was prepared and evaluated as support for enzyme immobilization. In this work a lipase sn-1,3 specific from Rhizopus oryzae was physically immobilized in CS-GP by adsorption (PA) and in CS-GP modified chemically with glutaraldehyde (CS-GP-GA) by covalent attachment (CA). The matrices (pure and chemically modified) and immobilized lipases were characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric (TG) analysis. Moreover, a comparative study between free and immobilized lipase was provided in terms of pH, temperature, kinetic parameters and thermal stability. The catalytic properties of biocatalysts were assayed in olive oil hydrolysis. The maximum activities were found at 60◦C/pH 8.5 and 50◦C/pH 7.5 for lipase immobilized by PA and CA, respectively. Both immobilization process turned biocatalysts highly active, since they were stable for 120 days at low (-10◦C) temperatures and around 2-fold more stable than free lipase at 60◦C (high temperature). Thus, results revealed the potential application of chitosan/glycerol phosphate hydrogel (CS-GP) as matrix for lipase immobilization. Nevertheless, better performance was achieved when the lipase was immobilized by covalent attachment.

Abstract Plastic disposal is a worldwide issue due to its long degradation time. Environmentally degradable polymers (EDPs) have received considerable attention because of their faster degradation. However, the use of EDPs is limited by high cost and restricted properties. The incorporation of organic fillers is an alternative to reduce cost while increasing biodegradation. Poly-caprolactone (PCL) is a biodegradable polyester compatible with organic fillers. Coffee husk (CH) is a sub-product of coffee processing with potential use as organic filler. We prepared a novel PCL-CH composite film and investigated the effects of CH incorporation on the biodegradation of PCL. Biodegradation study was carried out in soil for 120 days, and evaluated by weight loss measurements. Additionally, soil microbiological and granulometric analyses were performed. Bacteria and fungi were found in the soil that was classified as sandy. The composite film degraded twice faster than PCL film probably due to the adhesion of microorganisms on the coffee husk.

Introduction: Bone diseases, aging and traumas can cause bone loss and lead to bone defects. Treatment of bone defects is challenging, requiring chirurgical procedures. Bone grafts are widely used for bone replacement, but they are limited and expensive. Due to bone graft limitations, natural, semi-synthetic, synthetic and composite materials have been studied as potential bone-graft substitutes. Desirable characteristics of bone-graft substitutes are high osteoinductive and angiogenic potentials, biological safety, biodegradability, bone-like mechanical properties, and reasonable cost. Herein, we prepared and characterized potential bone-graft substitutes composed of calcium phosphate (CP) - a component of natural bone, and chitosan (CS) - a biocompatible biopolymer. Methods CP-CS composites were synthetized, molded, dried and characterized. The effect of drying temperatures (38 and 60 °C) on the morphology, porosity and chemical composition of the composites was evaluated. As well, the effects of drying temperature and period of drying (3, 24, 48 and 72 hours) on the mechanical properties - compressive strength, modulus of elasticity and relative deformation-of the demolded samples were investigated. Results Scanning electron microscopy and gas adsorption-desorption analyses of the CS-CP composites showed interconnected pores, indicating that the drying temperature played an important role on pores size and distribution. In addition, drying temperature have altered the color (brownish at 60 °C due to Maillard reaction) and the chemical composition of the samples, confirmed by FTIR. Conclusion Particularly, prolonged period of drying have improved mechanical properties of the CS-CP composites dried at 38 °C, which can be designed according to the mechanical needs of the replaceable bone.

The present work demonstrates preparation of magnetic nanoparticles by a novel method. Magnetic nanoparticles with potential for biomedical and environmental applications were obtained by homogeneous coprecipitation method sonochemically assisted. The effect of ultrasonic cavitation on changing the reaction environment was studied. The chemical reaction media used here was very similar to those used for Sono-Fenton process. The ultrasonic energy has driven the growth of particles; smaller diameter nanoparticles were obtained by applying a higher power. For the first time, it was demonstrated the iron oxide nanoparticles synthesis at pH lower than 6.

Chitosan is soluble in diluted acid solutions and can easily form films by casting. However, residual acid neutralization should be performed for biomedical applications what may compromise physical and mechanical properties of the films. Thus, plasticizers can be added to improve these properties. The aim of this study was to characterize morphological, barrier and mechanical properties, besides evaluate the in vitro cytotoxicity of sorbitol-plasticized and NaOH-Na2CO3 neutralized chitosan membranes for skin substitute application. Scanning electron microscopy, X-ray diffraction, water vapor permeability and mechanical tests were carried out to characterize the obtained membranes. Moreover, Vero cells were used for in vitro cytotoxicity evaluation. In this paper, we report a non-cytotoxic sorbitol-plasticized chitosan membrane with desirable properties for skin substitution, such as flexibility, water vapor permeability and high percentage of elongation.

O objetivo deste estudo foi avaliar os efeitos da membrana (filme) de quitosana no processo de reparação de feridas cutâneas distais em equinos. Foram induzidas feridas cutâneas nas regiões metacarpianas e metatarsianas de quatro equinos adultos. No grupo tratado, oito feridas foram recobertas com membrana de quitosana e, no grupo controle, apenas higienização com solução de cloreto de sódio 0,9%. No período experimental, foram avaliados o diâmetro da ferida, formação de tecido de granulação exuberante, tipo de exsudato que a recobria, análise histológica, bem como as características da membrana de quitosana (plasticidade durante manipulação e presença ou ausência da membrana a cada troca). A membrana de quitosana não interferiu no tempo de cicatrização, podendo servir como material de recobrimento de feridas cutâneas, potencialmente com vantagens, se for empregada como meio condutor de substâncias que interfiram positivamente no processo cicatricial, abrindo campo para novos estudos.

The aim of this study was to evaluate the effects of chitosan film on wound repair in horse distal limb. Skin wounds were induced on metacarpus and metatarsus region of four adults horses. On treat group, eight wounds were covered with chitosan film and on control group sodium chlorid 0.9% was used. During the experimental period, it was evaluated the wound diameter, exuberant granulation tissue formation, kind of exudat, histological analyzes, and some characteristics of the chitosan film (plasticity during handling and presence or absence of film on each change). The chitosan film had not interfered on healing time, might serving to cover skin wounds, with potential advantages, if it is used as a conductive of substances that interfere positively in the healing process, opening a field to news studies.