Drugs adsorption and release behavior of collagen/bacterial cellulose porous microspheres

A porous microsphere with good biocompatibility was fabricated based on collagen (COL) and bacterial cellulose (BC). The adsorption and release behaviors of the COL/BC porous microspheres were studied using BSA as the model protein, and employing quasi-primary, quasi-secondary, and Kannan-Sundaram intragranular diffusion models, zero-order, first-order, Higuchi and Korsmeyer-Peppas models. The results showed that the COL/BC porous microspheres are beneficial to the proliferation of MC3T3 E1-cells. The linear Langmuir equation can accurately describe the adsorption equilibrium relationship of BSA to the COL/BC microspheres. The pseudo-second-order model can more accurately explain and predict the membrane diffusion kinetics of BSA than both pseudo-primary-order and Kannan-Sundaram intragranular diffusion models. The adsorption rate was affected by both membrane and intragranular diffusions. The drug release behavior indicated that the microsphere-loaded BSA was primarily adsorbed at the inner wall of the pore, and exhibited the characteristics of a scaffold-based matrix meanwhile. The drug release kinetics can be accurately described by the first-order release model. The present study elucidated the mechanism of drug adsorption and release of COL/BC porous microspheres and provided a theoretical basis for its application in controlled release technology.