Azospirillum brasilense AbV5/6 encapsulation in dual-crosslinked beads based on cationic starch.

The main challenge of agriculture is feeding the growing population and at the same time providing environmental sustainability. Using Azospirillum brasilense as a biofertilizer has proved to be a promising solution. However, its prevalence in soil has not been efficient due to biotic and abiotic stresses. Thus, to overcome this drawback, we encapsulated the A. brasilense AbV5 and AbV6 strains in a dual-crosslinked bead based on cationic starch. The starch was previously modified with ethylenediamine by an alkylation approach. Then, the beads were obtained by a dripping technique, crosslinking sodium tripolyphosphate with a blend containing starch, cationic starch, and chitosan. The AbV5/6 strains were encapsulated into the hydrogel beads by a swelling diffusion method followed by desiccation. Plants treated with encapsulated AbV5/6 cells showed an increase in the root length by 19 %, shoot fresh weight by 17 %, and the content of chlorophyll b by 71 %. The encapsulation of AbV5/6 strains showed to keep A. brasilense viability for at least 60 days and efficiency to promote maize growth.

Chemically crosslinked guar gum hydrogels: An investigation on the water transport and its relationship with hydrocortisone release.

In this work, we describe the synthesis, the characterization, and the potential application of a pH-responsive guar gum-based hydrogel. The polysaccharide produced permanent hydrogels with improved biocompatibility. In this work, we report the chemical modification of guar gum (with glycidyl methacrylate) and its use, as the main constituent, in obtaining chemically cross-linked hydrogels. The morphology, swelling properties, and cytotoxicity of the resulting materials were studied in-depth. The hydrogels showed to be pH-responsive, and non-toxic being safe to use it as a biomaterial. In addition, we tested the potential of this one as a drug carrier. Herein, we have chosen hydrocortisone (HCS) as a drug model. The mechanism of HCS release changed as a function of pH, owing to different responses in each medium. Our results indicate that the guar gum hydrogels have great potential to be used, with safety, as a drug carrier.

Chitosan-based hydrogels: From preparation to biomedical applications.

The advances in the field of biomaterials have led to several studies on alternative biocompatible devices and to their development focusing on their properties, benefits, limitations, and utilization of alternative resources. Due to their advantages like biocompatibility, biodegradability, and low cost, polysaccharides have been widely used in the development of hydrogels. Among the polysaccharides studied on hydrogels preparation, chitosan (pure or combined with natural/synthetic polymers) have been widely investigated for use in biomedical field. In view of potential applications of chitosan-based hydrogels, this review focuses on the most recent progress made with respect to preparation, properties, and their salient accomplishments for drug delivery and tissue engineering.

Aminodextran polymer-functionalized reactive magnetic emulsions for potential theranostic applications.

Aminodextran (AMD) polymer was prepared via chemical grafting of hexamethylenediamine on oxidized dextran. Magnetic latex particles were successfully obtained by adsorption of positively charged AMD on negatively charged submicron magnetic emulsion. The adsorbed amount was found to be ranged from 20 to 1280mg of AMD per gram of dried magnetic dispersion. The AMD-coated magnetic emulsions were characterized by positive zeta potential in the pH range from 3 to 9 compared to bare seed magnetic emulsion. All the samples showed to be superparamagnetic property, even after the adsorption of the polymer. The developed magnetic submicron particles exhibited good potential for in vivo biomedical diagnosis applications as demonstrated by their higher T2 contrast-ability compared to Gd in magnetic resonance imaging (MRI) and hyperthermia.

Magnetic nanoparticles: In vivo cancer diagnosis and therapy.

Recently, significant research efforts have been devoted to the finding of efficient approaches in order to reduce the side effects of traditional cancer therapy and diagnosis. In this context, magnetic nanoparticles have attracted much attention because of their unique physical properties, magnetic susceptibility, biocompatibility, stability and many more relevant characteristics. Particularly, magnetic nanoparticles for in vivo biomedical applications need to fulfill special criteria with respect to size, size distribution, surface charge, biodegradability or bio-eliminability and optionally bear well selected ligands for specific targeting. In this context, many routes have been developed to synthesize these materials, and tune their functionalities through intriguing techniques including functionalization, coating and encapsulation strategies. In this review article, the use of magnetic nanoparticles for cancer therapy and diagnosis is evaluated addressing potential applications in MRI, drug delivery, hyperthermia, theranostics and several other domains. In view of potential biomedical applications of magnetic nanoparticles, the review focuses on the most recent progress made with respect to synthetic routes to produce magnetic nanoparticles and their salient accomplishments for in vivo cancer diagnosis and therapy.