Facile fabrication of chitosan-based molecular imprinted microspheres to adsorb selectively, release and anti-bacteria for berberine.

Berberine hydrochloride (Ber), a bioactive compound widely found in the roots, rhizomes, stems and barks of Coptis chinensis, has demonstrated efficacy in treating many diseases, such as cancer, congestive heart failure, Alzheimer's disease, especially inflammatory caused by bacteria. The molecularly imprinted microspheres based on chitosan were fabricated to adsorb selectively, release and anti-bacteria of Ber. The Ber surface molecularly imprinted microspheres (Ber-PSSS@GCS-MIPs) were synthesized using crosslinked chitosan as matrix, Ber as template, and sodium 4-styrene sulfonate (SSS) as functional monomer via a redox surface-initiating system -NH2/-S2O82-. The microspheres were characterized by fourier transform infrared reflection (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Adsorption kinetics, isotherms and imprinting factor were investigated, and the drug release performance and antibacterial activity were evaluated. As a result, via electrostatic interaction and "lock-key" imprinted cavities, the adsorption capacity of Ber-PSSS@GCS-MIPs reaches 185 mg/g at 2 h, significantly higher than 51 mg/g observed for non-imprinted microspheres. The adsorption of Ber-PSSS@GCS-MIPs. follows pseudo-second-order kinetics, with adsorption amount decreasing as temperature increases and salt concentration rises. Ber-PSSS@GCS-MIPs show excellent recognition and selectivity with an imprinting factor of 3.07, a selectivity factor exceeding to 2. The adsorption capacity remains at 82.4 % of three times cycles. The Ber-PSSS@GCS-MIPs loaded drug microspheres attain slow and sustained release for 70 % at 139 h. The relative antibacterial rate of Ber-PSSS@GCS-MIPs loaded Ber is higher than non-imprinted microsphere and control against S. aureus and E. coli.