Chitosan hybrid microgels for oral drug delivery.

In the present work, hybrid microgels based on chitosan and SiO2 nanoparticles (NPs) were synthesized. Both chitosan and the SiO2 NPs were submitted to chemical modification reactions to having vinyl groups incorporated into their structures. The microgels were synthesized by emulsion polymerization. SEM analysis indicated a high dispersity of diameter for the microgels, ranging between (18.7 ±â€¯12.3) µm for the samples without SiO2-VTS and (11.3 ±â€¯8.07) µm for the microgels with SiO2-VTS. The material showed pH-responsiveness, especially in acidic pHs. The longest release lasted 45 min and large amounts of drugs were released as soon as the material was added to the release medium. It is interesting for oral drug delivery systems, especially for gastric wound treatment. The fast release of high amounts of drugs promotes an immediate relief of the pain and the following controlled release allows the gradual recovery of the damaged area.

Submicron magnetic core conducting polypyrrole polymer shell: Preparation and characterization.

Magnetic particles are of great interest in various biomedical applications, such as, sample preparation, in vitro biomedical diagnosis, and both in vivo diagnosis and therapy. For in vitro applications and especially in labs-on-a-chip, microfluidics, microsystems, or biosensors, the needed magnetic dispersion should answer various criteria, for instance, submicron size in order to avoid a rapid sedimentation rate, fast separations under an applied magnetic field, and appreciable colloidal stability (stable dispersion under shearing process). Then, the aim of this work was to prepare highly magnetic particles with a magnetic core and conducting polymer shell particles in order to be used not only as a carrier, but also for the in vitro detection step. The prepared magnetic seed dispersions were functionalized using pyrrole and pyrrole-2-carboxylic acid. The obtained core-shell particles were characterized in terms of particle size, size distribution, magnetization properties, FTIR analysis, surface morphology, chemical composition, and finally, the conducting property of those particles were evaluated by cyclic voltammetry. The obtained functional submicron highly magnetic particles are found to be conducting material bearing function carboxylic group on the surface. These promising conducting magnetic particles can be used for both transport and lab-on-a-chip detection.