Molecular imprinting functionalized silica xerogel for selective recognition of levorotatory ofloxacin

Synthesis of a surface molecular imprinting polymer based on silica and its application in the identification of nitrocellulose

A surface molecular imprinting polymer (MIP) based on silica (SiO₂/MIP) with excellent selective identification properties towards nitrocellulose (NC) was synthesized with methylacrylic acid as a functional monomer and NC as a template molecule, through simple in situ polymerization. The functional groups of SiO₂/MIP were studied through Fourier transform infrared spectroscopy. The morphology, crystalline state and thermostability of SiO₂/MIP were investigated respectively by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. Binding capacity and selectivity studies of SiO₂/MIP for NC and its analogues were carried out through ultraviolet-visible spectrophotometry. The thermal analysis and study of crystalline states confirmed the successful imprinting of NC in the polymer networks. The optimized conditions were found to be a polymerization temperature of 45 °C and a functional monomer to cross-linking ratio of 1 : 3. The adsorption capacity of SiO₂/MIP was improved considerably compared with that of polymers prepared by traditional imprinting technology, with a maximum adsorption amount of 1.7 mg mg⁻¹ in 2 mg ml⁻¹ NC solution, compared with an adsorption capacity of about 0.5 mg mg⁻¹ for a traditional MIP. According to the selectivity study, more NC was adsorbed by SiO₂/MIP than its analogues; the best adsorption capacity of SiO₂/MIP for NC was approaching 5 times that for carboxymethyl cellulose (CMC). The results show that it would be possible to apply SiO₂/MIP for the detection of NC, to give improved sensitivity in security checking and improved contaminant adsorption.

A novel surface molecular imprinting polymer was prepared which displayed excellent specificity, selectivity and a large adsorption capacity for nitrocellulose.

Cellular level evaluation and lysozyme adsorption regulation of bimodal nanoporous silica

The present work initially evaluated cellular toxicity and uptake of our previous biomimetic bimodal nanoporous silica (B-BNS) and applied it as lysozyme adsorbent, which aimed to study potential ability of B-BNS as antitumor biological macromolecules carrier. To highlight the advantage of bimodal mesopores, comparisons were made between single mesoporous silica nanoparticles (S-MSN) and B-BNS. Cell evaluation work was conducted using MCF-7 cells and lysozyme adsorption process was studied with pH and lysozyme concentration as independent variables. The results indicated that the toxicity of S-MSN and B-BNS on MCF-7 cell could be neglected. In addition, S-MSN and B-BNS had the ability to be uptaken into cells and even nucleus evidenced by inverted fluorescence microscope and confocal laser scanning microscopic. Compared to S-MSN, B-BNS adsorbed larger amount of lysozyme due to its bimodal mesopores. Lysozyme adsorption was favorably approximated by the pseudo-second order model. The equilibrium data of lysozyme adsorption were fitted to the Langmuir isotherm model much better than the Freundlich isotherm model, suggesting that lysozyme adsorption on B-BNS via the monolayer adsorption process. Overall, B-BNS can be considered as good antitumor biological macromolecules carrier.