RESUMO
A detailed study of biomaterials is mandatory to comprehend their feasible biomedical applications in terms of drug delivery and tissue regeneration. Particularly, mucoadhesive biopolymers such as chitosan (chi) and carboxymethylcellulose (CMC) have become interesting biomaterials regards to their biocompatibility and non-toxicity for oral mucosal drug delivery. In this work, pH-responsive biopolymer-silica composites (Chi-SiO2, Chi-CMC-SiO2) were developed. These two types of composites presented a different swelling behavior due to the environmental pH. Moreover, the nanocomposites were loaded with aqueous Larrea divaricata Cav. extract (Ld), a South American plant which presents antioxidant properties suitable for the treatment of gingivoperiodontal diseases. Chi-CMC-SiO2 composites showed the highest incorporation and reached the 100% of extract release in almost 4â¯days while they preserved their antioxidant properties. In this study, thermal and swelling behavior were pointed out to show the distinct water-composite interaction and therefore to evaluate their mucoadhesivity. Furthermore, a cytotoxicity test with 3T3 fibroblasts was assessed, showing that in both composites the addition of Larrea divaricata Cav. extract increased fibroblast proliferation. Lastly, preliminary in vitro studies were performed with simulated body fluids. Indeed, SEM-EDS analysis indicated that only chi-SiO2 composite may provide an environment for possible biomineralization while the addition of CMC to the composites discouraged calcium accumulation. In conclusion, the development of bioactive composites could promote the regeneration of periodontal tissue damaged throughout periodontal disease and the presence of silica nanoparticles could provide an environment for biomineralization.
Assuntos
Antioxidantes/farmacologia , Biopolímeros/farmacologia , Compostos de Bifenilo/antagonistas & inibidores , Larrea/química , Picratos/antagonistas & inibidores , Extratos Vegetais/farmacologia , Dióxido de Silício/farmacologia , Células 3T3 , Animais , Antioxidantes/química , Biopolímeros/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Camundongos , Nanopartículas/química , Tamanho da Partícula , Extratos Vegetais/química , Dióxido de Silício/química , Propriedades de SuperfícieRESUMO
Nowadays, the research of innovative drug delivery devices is focused on the design of multiple drug delivery systems, the prevention of drug side effects and the reduction of dosing intervals. Particularly, new mucosal delivery systems for antimicrobials, antioxidants and anti-inflammatory drugs has a growing development, regards to the avoidance of side effects, easy administration and a suitable drug concentration in the mucosa. In this work, chitosan hydrogels are evaluated as a biodegradable scaffold and as a bioactive agent carrier of an antioxidant-antimicrobial compound called thymol. Throughout the study, swelling behavior, viscoelastic properties and thermal analysis are highlighted to present its advantages for a biomedical application. Furthermore, the in vitro results obtained indicate that thymol-chitosan hydrogels are biocompatible when exposed to [3T3] fibroblasts, exhibit antimicrobial activity against Staphylococcus aureus and Streptococcus mutans for 72h and antioxidant activity for 24h. These are desirable properties for a mucosal delivery system for an antimicrobial-antioxidant dual therapy for periodontal disease.
Assuntos
Hidrogéis/química , Anti-Infecciosos , Antioxidantes , Quitosana , Sistemas de Liberação de Medicamentos , Humanos , Staphylococcus aureus , TimolRESUMO
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.
Assuntos
Poluentes Ambientais/análise , Nanopartículas/análise , Nanoestruturas/análise , Eletroforese Capilar/métodosRESUMO
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.
RESUMO
Silica-collagen type I nanocomposite hydrogels are evaluated as medicated dressings to prevent infection in chronic wounds. Two antibiotics, gentamicin and rifamycin, are encapsulated in a single step within plain silica nanoparticles. Their antimicrobial efficiency against Pseudomonas aeruginosa and Staphylococcus aureus is assessed. Gentamycin-loaded 500 nm particles can be immobilized at high silica dose in concentrated collagen hydrogels without modifying their fibrillar structure or impacting on their rheological behavior and increases their proteolytic stability. Gentamicin release from the nanocomposites is sustained over 7 days, offering an unparalleled prolonged antibacterial activity. Particle immobilization also decreases their cytotoxicity towards surface-seeded fibroblast cells. Rifamycin-loaded 100 nm particles significantly alter the collagen hydrogel structure at high silica doses. The thus-obtained nanocomposites show no antibacterial efficiency, due to strong adsorption of rifamycin on collagen fibers. The complex interplay of interactions between drugs, silica and collagen is a key factor regulating the properties of these composite hydrogels as antibiotic-delivering biological dressings and must be taken into account for future extension to other wound healing agents.
RESUMO
The synthesis of monodispersed magnetic silica nanoparticles (MSN) is described using a water-in-oil reverse microemulsion system that does not require the use of co-surfactants. Sodium silicate, Tween 20 as a neutral surfactant and 1-butanol as the organic phase were used. There are several advantages of the proposed method including a saturation magnetization value of 10 emu/g for the particles obtained, uniformity of size and that they are easily functionalized to bind urease covalently. Moreover, the intra-day, inter-day and long-term stability results confirm that the procedure was successful and the enzyme-linked MSNs were stable over repeated uses and storage retaining more than 75% activity after 4 months.
Assuntos
Emulsões , Enzimas Imobilizadas/metabolismo , Magnetismo , Nanopartículas , Dióxido de Silício , Urease/metabolismo , Biotecnologia/métodos , Estabilidade Enzimática , Enzimas Imobilizadas/química , Urease/químicaRESUMO
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.