Polymeric microparticles of chitosan and alginate as accessible systems for drug delivery applications
Polymeric chitosan-alginate microparticles represent a promising strategy for encapsulation and controlled release of bioactive compounds. Among different techniques used to produce polymer-based microstructures, ionotropic gelation is an affordable alternative when using molecules with charged chemical groups. In this work, ionotropic gelation procedures were established to obtain reproducible and biocompatible microparticles through simultaneous gelation and sequential (two-step, core-shell) gelation. Microscopical characterization confirmed controllable sizes, while ATR-FTIR analysis evidenced stable polyelectrolyte complexes with ionic interactions and hydrogen bonding. Core-shell microparticles exhibited 35–55% higher bromothymol blue encapsulation capacity compared to homogeneous systems, confirming the superiority of structural compartmentalization. In vitro biocompatibility and hemolysis assays revealed a dose-dependent profile and the absence of cytotoxicity at dilutions 1:20 and 1:200 (viability >90%, hemolysis <2%). The systems produced constitute a versatile platform with potential for drug delivery applications, under simple and reproducible laboratory conditions.