Preparation and characterization of PEM-coated alginate microgels for controlled release of protein

Abstract

In this study, calcium-alginate microgels coated with a polyelectrolyte multilayer (PEM) were fabricated as a controlled-release system. This system was constructed via an electrostatic droplet generation technique followed by a layer-by-layer (LbL) self-assembly technique. The electrostatic droplet generation technique was reported as an easy method of preparing microgels, due to their mild preparation conditions and ability to preserve the biological activity of the encapsulated drugs. With the LbL self-assembly technique, the PEM could be fabricated on the microgels attributed to the electrostatic attraction between positive-charged chitosan (Chi) and negative-charged dextran sulfate (Dex). The properties of the prepared microgels were investigated using dynamic laser scattering (DLS), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectrum and zeta potential analyzer. In vitro release study indicated that the initial burst release of the bovine serum albumin (BSA) from PEM-coated microgels was less compared to the uncoated microgels (19% versus 31% in 24 h). In addition, the sustained release of BSA from the PEM-coated microgels was recorded up to 1 month without any damage to BSA integrity. Thus, our results demonstrated that the PEM-coated microgels not only prolonged the release time, but also relieved the initial burst problem to some degree and preserved the biological activity of the encapsulated drugs. Moreover, the release rate of BSA could be regulated by controlling the number of deposited layers. In conclusion, this study presented an easy yet effective method for the controlled, sustained release of biological macromolecules.

Acceleration of skin regeneration in full-thickness burns by incorporation of bFGF-loaded alginate microspheres into a CMCS-PVA hydrogel

“…bFGF‐loaded alginate Ms were prepared according to Zuo et al . (). Briefly, sodium alginate was dissolved in purified water to a concentration of 2.0% w/v, with overnight stirring at room temperature.…”

Layer-by-layer assembled milk protein coated magnetic nanoparticle enabled oral drug delivery with high stability in stomach and enzyme-responsive release in small intestine

“…Early studies have revealed that the layered coating structure could protect the drug more efficiently to realize the sustained release. [32] Meanwhile, most layered structures were microsized or had positive surface charge, which were unstable in the stomach, thus not suitable for the intestinal-specific drug delivery. In this study, the LBL-CN-DOX-IO nanoparticles showed a significant reduction of the initial rapid release of DOX from the amphiphilic inner polymer layer in the low pH conditions of the stomach fluid.…”

Recent Advances in Encapsulation, Protection, and Oral Delivery of Bioactive Proteins and Peptides using Colloidal Systems

“…For instance, the gastric stability of the enzymes was increased by trapping them inside biopolymer microgels with an antacid [126]. BSA has been trapped inside alginate microgels by coating them with successive layers of cationic (chitosan) and anionic (dextran sulfate) biopolymers [127]. Insulin has been trapped inside hydroxypropyl cellulose-polyglutamic acid microgels, which enhanced its stability under gastric conditions [128].…”