Improving affinity of β-cyclodextrin-based molecularly imprinted polymer using room temperature ionic liquid

Abstract

This paper reported the facile method of improving the affinity of β-cyclodextrins (β-CD)-based molecularly imprinting system by using the effect of interaction of β-CD and room temperature ionic liquids (RTILs). The molecularly imprinting polymers (MIPs) of β-CD matrices were prepared with β-CD, as functional monomer, hexanethylene diisocyante as crosslinker, and using aesculin as a model molecule in a RTIL (1-butyl-3-methylimidazolium tetrafluoroborate) of porogen. The RTILs/DMSO-based MIP (or NIP) showed smaller surface areas but greater pore size than the RTILs/DMSO-free MIP (or NIP). The equilibrium adsorption experiment indicated that the imprinting factor for the β-CD-based MIP prepared with RTILs was 2.25 and 1.19 for the controlled MIP prepared without RTILs. In addition, the values of effective diffusivity (Deff) of aesculin (AN) obtained from the RTILs-assisted β-CD MIP (10−16 cm2/s) was about seven times smaller than those from the RTILs-free controlled β-CD MIP, although the values of free diffusivity (D) of AN were all found in the order of 10−13 cm2/s. When used as release material, the relative bioavailability of the β-CD-based MIP prepared in RTIL displayed a markedly higher value of 399.7% than that of the commercial AN tablet. On the contrary, the β-CD-based non molecularly imprinted polymer (NIP) prepared in RTILs, β-CD-based MIP prepared in non-RTILs and β-CD-based NIP prepared in non-RTILs was only 88.6%, 179.3% and 157.0%, respectively. The results indicated that using RTIL as porogen is an effective approach to improving affinity of β-CD-based MIP.