Maria Lucia Foglia

A functional material that combines the Cr(VI) reduction activity of Burkholderia sp. with the adsorbent capacity of sol–gel materials

In the present work, Cr(VI) reduction in aqueous as well as in soil environments has been studied using free and sol–gel immobilized Burkholderia sp. Enhanced reduction rates were achieved by immobilized cells, which are found to be protected from the deleterious effects of high Cr(VI) concentrations. Immobilized bacteria showed enhanced performance in comparison with free cells because of the combination of bacteria biotransformation effect and chromium adsorption on silica matrices. Moreover, bacteria did not lose any activity after four cycles of reutilization. Bacteria immobilized in silica matrices had the ability to completely reduce 100 µg ml−1Cr(VI) after 4 days of incubation in aqueous media and to transform 200 µg ml−1Cr(VI) after 7 days in sterile soil. Immobilized bacteria demonstrated highly efficient Cr(VI) reduction over the Cr(VI) concentration range 50–500 µg g−1 and 200–800 µg g−1 in aqueous and soil environments, respectively. These results highlight the potential of this functional material that combines the biological activity of bacterial cells with the adsorbent capacity of sol–gel materials.

Development of Sol-Gel Hybrid Materials for Whole Cell Immobilization

The development of a good biocompatible matrix for immobilization of cells is very crucial for improving the performance of functional biohybrids. The synthesis of solid inorganic materials from alkoxide, aqueous and polyol-modified silanes routes, as well as the incorporation of organic polymers, are further areas being developed to improve the viability of encapsulated cells. This emerging field of material science has generated considerable and increasing interest during the past decade. Recent advances in the field involving biomaterials, biohybrids, and functional nanomaterials provided novel materials, which have gained the attention of the scientific community, Governments and industrial companies. Overall, this review is intended to give an overview on the current state of the art of the patents associated to the immobilization of whole living cells in sol-gel derived hybrid materials and to describe the major challenges to be addressed in the forthcoming years.

Recent patents on the synthesis and application of silica nanoparticles for drug delivery.

Drug delivery systems are designed to improve therapy efficacy as well as patient compliance. This could be accomplished by specifically targeting a medication intact to its active site, therefore reducing side-effects and enabling high local drug concentrations. Silica nanoparticles have gained ground in the biomedical field for their biocompatibility and biodegradability, being themselves inert and stable, thus enabling a variety of formulation designs for application in the pharmaceutical industry. This paper is a review of the recent patents on the applications of silica nanoparticles for drug delivery and their preparation. The review will focus on the different techniques available to obtain silica nanoparticles with variable morphology and their drug targeting applications, providing an overview of silica particles synthesis described in the literature.

A new method for the preparation of biocompatible silica coated-collagen hydrogels

Silica-collagen scaffolds were obtained by covalent binding of an aminosilane to glutaraldehyde fixed collagen hydrogels, rendering a three dimensional network of silicon coated collagen fibrils. When compared to non-silicified collagen, silica containing matrices exhibited a 60 fold increment in the rheological properties. Moreover, acellular degradation by collagenase type I indicated that enzymatic digestion occurred at a slower rate for silica modified hydrogels, hence enabling a controlled degradation of the obtained material. In addition, fibroblastic cells seeded on silicified collagen matrices were able to adhere, proliferate and migrate within the scaffold for over 3 weeks as shown by MTT tests and hematoxylin-eosin staining. These results suggest that the herein described method could be useful in the design of materials for tissue engineering purposes.

Advances in collagen, chitosan and silica biomaterials for oral tissue regeneration: from basics to clinical trials

Different materials have distinct surface and bulk characteristics; each of them potentially useful for the treatment of a particular wound or disease. By reviewing those materials that have reached a clinical stage the reader will have a broad panorama of the possibilities a particular material can offer, regarding its ability to support fast tissue regeneration. This review covers the most recent advances made towards the development of biomaterials aimed to support regenerative processes. Indeed, we highlight key examples, from basic research to clinical trials, of biomaterials for a specific biomedical application. In this context, the focus is made on collagen, chitosan and silica which are key representatives of a protein, a polysaccharide and an inorganic material usually employed as biomaterials. Particularly, this review article presents an overview of their potential therapeutics in the treatment of disorders within the oral mucosa and tooth supporting tissues. Finally, the importance of in vivo and in vitro studies, clinical evidence studies, systematic reviews and meta-analyses as an adequate guidance for biomaterial design and development is highlighted.

Nanotoxicological Effects of SiO2 Nanoparticles on Spodoptera frugiperda Sf9 Cells

The application of silica nanoparticles (NPs) in the biomedical field experienced a great development. The driving forces for these and future developments are the possibility to design NPs with homogeneous size and structure amenable to specific grafting. Moreover, it is possible to tune the characteristics of the NPs to meet the requirements of each specific cell and desired application. Herein, we analyzed the effect of silica NPs of various sizes and surface charge on the viability of Spodoptera frugiperda cells (Sf9 cell line) with the aim of extending the knowledge of possible toxicity of the NPs in the environment and development of new tools for insect control. Moreover, these results will also contribute to develop more effective systems for gene vectors delivery and recombinant proteins expression. Bare silica NPs of 14 nm, 380 nm and 1430 nm as well as amine-modified silica NPs of 131 nm and 448 nm were obtained by the Stöber method. The NPs were characterized by DLS and zeta potential measurements. The cell viability was assessed by the MTT test. It was observed that the 14 nm NPs possess the highest toxic effect. Indeed, after 24 h, the viability of the cells exposed to the lower concentration of NPs (0.12 mg/ml) was about 40% of the value obtained for the control cells not exposed to NPs. Moreover, the exposure to other negative charged NPs also causes a lower activity when compared with the control. Alternatively, lower concentrations of positive charged NPs (i.e.: 0.12 or 0.6 mg/ml) demonstrated to stimulate the proliferation of the cells and higher concentrations (i.e.: 7.2 mg/ml) did not present significant differences with the control. In conclusion, we have demonstrated that the NPs possess an effect that is highly influenced by the size, charge and concentration. Although, silica NPs are being used in the biomedical field, these results contribute to further understanding the risk that could be associated to nanoparticles and how these can be modified in order to meet the requirements of each desired application.

Nanoparticles and capillary electrophoresis: A marriage with environmental impact

The impact of nanomaterials in the environment and human health is a cause of big concern and even though intensive studies are currently being carried out, there is still a lot to elucidate. The development of validated methods for the characterization and quantification of nanomaterials and their impact on the environment should be encouraged to achieve a proper, safe, and sustainable use of nanoparticles (NPs). Recently, CE emerged as a well‐adapted technique for the analysis of environmental samples. This review presents the application of NPs together with CE systems for environmental pollutants analysis, as well as the application of CE techniques for the analysis of various types of NPs.

Preliminary Evaluation of Median Lethal Concentrations of Stöber Silica Particles with Various Sizes and Surface Functionalities Towards Fibroblast Cells

The application of silica particles in the biomedical field has experienced a great development in recent years, especially in the design of nanoparticles having homogeneous size, structure and amenable to specific grafting. In this way, it becomes possible to control the interaction of nanoparticles with cells in order to meet the requirements for desired applications. This work explores the cytotoxicity of silica particles of various sizes and surface functionality towards L929 fibroblast cells. In particular, the median lethal concentration of the different silica particles has been established. Preliminary investigations of silica nanoparticles prepared by the Stöber method with sizes ranging from 100 nm to 500 nm showed that the largest particles are less harmful for the cells. Moreover, cytotoxicity towards L929 fibroblasts was mainly observed for bare particles, whereas sulfonate-, amine- and thiol-grafted particles had less detrimental effects. This shows the key influence of particle surface curvature and chemistry on nanomaterials cytotoxicity.

Zoledronate and Related Impurities Analysis by Capillary Zone Electrophoresis

Fil: Alvarez, Gisela Solange. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Quimica y Metabolismo del Farmaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Quimica y Metabolismo del Farmaco; Argentina

3D In Vitro Models of Early Pregnancy: How to Choose the Right Scaffolding Material?

Following fertilization, the blastocyst has to complete two distinct steps to assure further development of pregnancy. After apposition it establishes a firm connection with the luminal epithelium of the endometrium (attachment) and subsequently enters the decidualizing stroma (invasion). If this step is not achieved successfully, fertility problems arise. Development of the placenta ensures an adequate supply of nutrients and gas between the mother and the fetus. Preeclampsia is a prevalent disorder arising from defects in the process of placentation. It is associated with an increase of maternal morbidity and mortality. Numerous attempts have been made in order to elucidate the etiology of the syndrome and identify women at risk. The lack of reliable animal models has turned the attention to the development of in vitro assays, which could provide a better insight into the individual processes that will later trigger preeclampsia symptoms. In particular, 3D in vitro models more closely resemble the complexity of the extracellular environment. The choice of the scaffolding material should be done carefully as cell-matrix interactions are very often as important as cell-cell interactions for the correct attachment, proliferation and differentiation of cells. The following review is aimed to provide a general overview of the scaffolds available for the in vitro modeling of these complicated systems as well as to discuss the importance surrounding the choice of the scaffolding material and its influence on the results obtained.