Nanosilica and copper ecotoxicity in Gambusia holbrooki fish.

When silica nanoparticles (SiNP) reach the water bodies interact with the already existing pollutants in the environments. This study aimed to evaluate the ecotoxicity of SiNP under the presence/absence of Cu in mosquitofish (Gambusia holbrooki). Fish were exposed to 0, 10 and 100 mg SiNP L-1, alone or mixed with Cu (0.25 mg L-1). After 96 h, the amount of colony forming units (CFU) of bacteria living on the skin mucus was analysed, and oxidative stress, tissue damage enzymes, and neurotoxicity were evaluated. We observed a reduction in CFU when Cu was present in the media. The liver was the target organ, evidencing a decrease in tissue damage enzymatic activities, activation of the antioxidant system in all treatments, and lipid oxidative damage when the SiNP and Cu were mixed. Overall, SiNP ecotoxicity was proved, which could also be enhanced by the presence of ubiquitous elements such as metals.

Applied of actinobacteria consortia-based bioremediation to restore co-contaminated systems.

Global industrialization and natural resources extraction have left cocktails of environmental pollutants. Thus, this work focuses on developing a defined actinobacteria consortium able to restore systems co-contaminated with pollutants occurring in Argentinian environments. In this context, five actinobacteria were tested in solid medium to evaluate antagonistic interactions and tolerance against lindane (LIN), Reactive Black B-V (RBV), phenanthrene (Ph) and Cr(VI). The strains showed absence of antagonism, and most of them tolerated the presence of individual pollutants and their mixtures, except Micromonospora sp. A10. Thus, a quadruple consortium constituted by Streptomyces sp. A5, M7, MC1, and Amycolatopsis tucumanensis DSM 45259T, was tested in liquid systems with individual contaminants. The best microbial growth was observed in the presence of RBV and the lowest on Cr(VI). Removals detected were 83.3%, 65.0% and 52.4% for Ph, RBV and LIN, respectively, with absence of Cr(VI) dissipation. Consequently, the consortium performance was tested against the organic mixture, and a microbial growth similar to the biotic control and a LIN removal increase (61.2%) were observed. Moreover, the four actinobacteria of the consortium survived the mixture bioremediation process. These results demonstrate the potential of the defined actinobacteria consortium as a tool to restore environments co-contaminated with organic pollutants.

Recent Advances in Synthetic and Natural Biomaterials-Based Therapy for Bone Defects.

Synthetic and natural biomaterials are a promising alternative for the treatment of critical-sized bone defects. Several parameters such as their porosity, surface, and mechanical properties are extensively pointed out as key points to recapitulate the bone microenvironment. Many biomaterials with this pursuit are employed to provide a matrix, which can supply the specific environment and architecture for an adequate bone growth. Nevertheless, some queries remain unanswered. This review discusses the recent advances achieved by some synthetic and natural biomaterials to mimic the native structure of bone and the manufacturing technology applied to obtain biomaterial candidates. The focus of this review is placed in the recent advances in the development of biomaterial-based therapy for bone defects in different types of bone. In this context, this review gives an overview of the potentialities of synthetic and natural biomaterials: polyurethanes, polyesters, hyaluronic acid, collagen, titanium, and silica as successful candidates for the treatment of bone defects.

Stimuli-Responsive Materials for Tissue Engineering and Drug Delivery.

Smart or stimuli-responsive materials are an emerging class of materials used for tissue engineering and drug delivery. A variety of stimuli (including temperature, pH, redox-state, light, and magnet fields) are being investigated for their potential to change a material's properties, interactions, structure, and/or dimensions. The specificity of stimuli response, and ability to respond to endogenous cues inherently present in living systems provide possibilities to develop novel tissue engineering and drug delivery strategies (for example materials composed of stimuli responsive polymers that self-assemble or undergo phase transitions or morphology transformations). Herein, smart materials as controlled drug release vehicles for tissue engineering are described, highlighting their potential for the delivery of precise quantities of drugs at specific locations and times promoting the controlled repair or remodeling of tissues.