Cellulose nanocrystal-based hydrogel microspheres prepared via electrohydrodynamic processes for controlled release of bioactive compounds.

Controlled release systems (CRSs) have been sought after as a compelling platform for site-specific delivery of bioactive compounds (BCs), including traditional drugs and food supplements. However, their potential is often hindered by challenges such as non-uniformity and structural instability. This study utilized an electrohydrodynamic (EHD) process to synthesize composites of cellulose nanocrystals (CNCs) (in two forms: colloidal (c) and crosslinked (x)) and alginate (ALG) to produce uniformly shaped hydrogel microspheres (HMs), serving as pH-sensitive CRSs for BC encapsulation. Hydrophobic and hydrophilic dyes, as model BCs, were loaded in HMs. Bead shapes were assessed by sphericity factors (values ≤0.05). Size depended on applied voltage, as it ranged from ∼1200 μm (voltage-OFF) to 300 μm (voltage-ON). Release mechanism of dye-loaded HMs was studied at pH 2.4 and pH 8.2 (to mimic acidic conditions in stomach and basic conditions in small intestine) using Korsmeyer-Peppas model. Release exponents (n) of dyes for different compositions indicated pH-dependent delivery through non-Fickian diffusion (0.43 ≤ n ≤ 0.85) and case-II transport (n ≥ 0.85) mechanisms. BC-loaded cCNC-ALG and xCNC-ALG composites, prepared via EHDs, demonstrated potential for designing efficient pH-sensitive CRSs for applications in various industries, ranging from nutraceutical and pharmaceutical to food and agriculture.