Metal Oxides Functionalized Paper-Based Device For Biosensing Application

With the development of science and technology,biosensors not only are applied to detect target analytes about various diseases,but also have become an important driving force for early diagnosis of diseases.Generally,multiple individually complex steps are required for common assays.Therefore,it is very significant to construct a novel sensing platform with the advantages of low price,operation-to-easy,high sensitivity and high selectivity,which is beneficial for performing the rapid and facile assays.Since the paper-based analytical devices are reported,the paper-based analytical devices open up rich possibility for rapid detection due to paper with the inherit merits of low cost,universality,portability,easy folding and high biocompatibility.The paper-based analytical devices based on the excellent properties of metal oxides and the advantages of paper substrates were fabricated for novel sensing systems.Through exploring the photoelectrochemical?PEC?and colorimetric mechanism,the analytical devices were constructed for the highly sensitive detection of a variety of targets.The main research work has been carried out as follows:?1?ZnFe₂O₄ magnetic nanoparticles?ZnFe₂O₄ NPs?wrapped by molecularly imprinted polymer?MIP?membranes were successfully functionalized in the cellulose paper,which led to cavities for the binding of BPA with high adsorption performance.The as-prepared ZnFe₂O₄NPs as peroxidase mimetics were utilized to catalyze oxidation of3,3?,5,5?-tetramethylbenzidine,resulting in forming the colored product with respective intensity.With the advantages of highly sensitivity,good selectivity and excellent regeneration,a novel paper-based sensor was successfully developed for the visual detection of bisphenol A.?2?The paper-based analytical devices with the multi-dimensional fluid channel were designed by utilizing the hydrophilicity of cellulose and the hydrophobicity of wax.With ingenious design of actuating conversion process between hydrophilicity and hydrophobicity,the steps of washing was automatically achieved in the assay procedures.The CdS quantum dots sensitized leaf-shape ZnO?CdS QDs/ZnO?structure was assembled on paper electrode to obtain the amplified PEC response.Then Au-modified prism-anchored octahedral CeO₂nanoparticles?Au@PO-CeO₂ NPs?were immobilized on the CdS QDs/ZnO to adjust PEC process.The proposed PEC/visual paper-based device was achieved by employing the catalytical properties of Au@PO-CeO₂ NPs.?3?A paper-based analytical device was designed with multi-plate serrate zinc oxide nanoflowers?ZnO NFs?and MIP membranes as two functional parts on the cellulosic matrix,which achieved for the separation of photoactive substances and recognition elements.On the basis of the excellent photoelectric property of ZnO NFs and binding capability of MIP membranes,the signal amplified strategy was accomplished by establishing the inherent connection between electrons transfer process and target molecules.The as-designed analytical device not only exhibited the highly sensitive detection of analytes under ultraviolet light,but also avoided damage of ultraviolet light for biomolecules.