Preparation And Characterization Of Molecularly Imprinted Layer-coated Silica Polymers Of Paclitaxel

Paclitaxel is a highly functionalized diterpene member of the taxane class of compounds.Since its special anticancer mechanism and significant anticancer effects were reported,paclitaxel has been most widely used for cancer treat in recent years. Due to the existence ofpaclitaxel in nature samples at low concentrations, and because of the complexity of the plantmatrices and the structural similarity to other taxane class of compounds, small or large-scalepreparation of paclitaxel is high-cost and highly selective materials are very needed in microand trace analysis.Molecularly imprinted polymers (MIPs) are tailor-made synthetic materials withselective molecular recognition capability. At present, many methods for preparation of MIPshave been proposed. These efforts have met with some limitations including incompletetemplate removal, small binding capacity, and irregular materials’ shape. One reason is that itis quite difficult to extract original templates located at the interior area of bulky materials.Molecularly imprinted nanoparticles have a small dimension with extremely high surface tovolume ratio, so that most of recognition sites are situated at the surface of the material andthis makes templates faster rebinding and easier removing due to easy accessibility and lowmass transfer resistance to target molecules. Herein, a highly selective molecular imprintingpolymer for paclitaxel was synthesized by molecular imprinting technique on the supporter ofsilica nanoparticles.Uniform silica nanoparticles were prepared by the hydrolysis of tetraethoxysilane withammonium hydroxide. Highly selective non-covalent molecularly imprinted layer-coatedsilica nanoparticles for paclitaxel were synthesized by molecular imprinting technique with asol–gel process on the supporter of silica nanoparticles with the aminopropyltriethoxysilanean functional monomer, tetraethoxysilane as cross-linker agent and HAc as a catalyst. Themorphology of the obtained polymers was characterized and the binding properties of theimprinted polymers were evaluated. Scatchard analysis revealed that two classes of bindingsites were formed in the imprinted polymers with equilibrium dissociation constants of0.0509g·L-1and0.0094g·L-1, respectively. Paclitaxel and its analogue were employed for selectivity tests. The results indicated that the imprinted polymers exhibited good selectivity andspecificity toward paclitaxel.Uniform silica nanoparticles were prepared by the hydrolysis of tetraethoxysilane withammonium hydroxide. Highly selective semi-covalent molecularly imprinted layer-coatedsilica nanoparticles for paclitaxel were synthesized by molecular imprinting technique with asol–gel process on the supporter of silica nanoparticles with the aminopropyltriethoxysilaneas functional monomer, tetraethoxysilane as cross-linker agent and HAc as a catalyst. Themorphology of the obtained polymers was characterized and the binding properties of theimprinted polymers were evaluated. the static rebinding experiments revealed that theimprinted polymers displayed high adsoption capacity for paclitaxel.