Rational design of molecularly imprinted photonic films assisted by chemometrics

Molecularly imprinted photonic polymer (photonic MIP) film can be prepared based on the combination of colloidal-crystal templating and molecular imprinting techniques. This kind of film is an ideal sensing material due to its distinct advantages such as high selectivity, rapid response and signal self-reporting. However, for the successful formation of this kind of sensing material, with high selectivity towards the imprinted molecules, a highly ordered and interconnected 3D macroporous structure, and a visually perceptible color change like pH-paper, each fabrication is strongly dependent on the determination of the main factors and an arduous process of preparation. In this work, the rational design of molecularly imprinted photonic film was realized by using response surface methodology (RSM) based on central composite design (CCD). Design of experiments following CCD allows selected factors to be changed systematically and simultaneously, thus reducing the number of experiments necessary. 20 photonic MIPs with different ratios of monomer : crosslinker : solvent were synthesized and their sensing properties were checked. Data were analyzed using analysis of variance (ANOVA). A second-order polynomial model was used for predicting the response. This model revealed that the crosslinker was dominant in the performance of photonic MIPs, and also allowed the optimum polymer composition to be predicted. Creatinine was used as the model analyte. Under the predicted optimum conditions, a sensor for the convenient detection of creatinine was fabricated with high sensitivity, quick response, and good stability. This also testifies to the fact that the RSM approach is appropriate to investigate the interactive effect of the selected factors and optimize polymerization recipes with a limited number of experiments. It is anticipated that this method opens a way to the efficient fabrication of photonic MIPs.