Preperation Of Molecularly Imprinted Optical Sensors Based On Carbon Dots And Its Applications In Proteins Recognition

The isolation and detectin of low abundance proteins are often of great importance in diagnosis and treatment.Molecular imprinting technique is one of the most promising and simple separation methods for generating predetermined selective molecular recognition sites in synthetic polymers.At present,the imprinting of biomacromolecules and specific proteins has attracted considerable interest from researchers.However,since many properties of proteins such as flexible conformation,large size,complex surface structure,solubility,and sensitivity to the environment,greatly affect their imprinting effects.Therefore,more and more researchers are looking for a mild,simple,and rapid protein detection method to overcome these problems.Carbon dots?CDs?,as a member of the carbon-based nanomaterial family,have excellent optical properties,chemical stability,and good water solubility,and thus have attracted much attentions in the field of chemical sensing.In recent years,molecularly imprinted fluorescence sensors that combine the high selectivity of molecular imprinting technology and the flurescence sensitivity of carbon dots have stood out in many fields such as chemical and biological analysis,and have become one of the powerful methods for detecting trace analytes in complex samples.Based on the above research background,we designed and prepared molecularly imprinted fluorescent sensors for protein detection by using carbon dots as the fluorescent signal,N-isopropylacrylamide?NIPAAm?and 3-aminopropyltriethoxysilane?APTES?as the thermo-sensitive monomer and functional monomer.The main research contents are as follows:1.Using the surface imprinting method,an imprinting polymer was prepared with the silanized carbon dots?CDs/SiO₂?as the fluorescent signal,N-isopropylacrylamide as the temperature sensitive monomer,and bovine hemoglobin?BHb?as the template.It was characterized by Fourier transform infrared spectroscopy,high resolution transmission electron microscopy,and fluorescence spectroscopy.Under optimal conditions,the fluorescence intensity of the sensor linearly quenched with increasing BHb concentration.The linear fluorescence quenching range was 0.02-0.10 mg/mL,the detection limit was 0.01g/mL,and the imprinting factor IF is 3.The prepared molecularly imprinted fluorescence sensor can selectively capture the target protein BHb.The competition binding experiments indicate that the sensor has high selectivity and recognition specificity for the target protein.In addition,the sensor was successfully applied to determine the amount of BHb in biological samples.2.Using the surface imprinting method,a molecularly imprinted fluorescence sensor for detecting OVA was prepared with CDs/SiO₂ as the fluorescent signal and ovalbumin?OVA?as the template molecule.The sensor has a fluorescence response to temperature,and the fluorescence intensity changes with temperature.It can be used as a temperature switch to control the recognition and release of the target protein OVA.In addition,the sensor was used for quantitative detection of OVA with a linear detection range of 0.02-0.08 mg/mL and a detection limit of 0.01 g/mL.And the sensor shows a good selectivity to OVA and can specifically recognize OVA.The sensor can accurately determine the content of OVA in the urine sample,and the recovery is 95.9-104.1%.3.The lipase molecularly imprinted polymer was prepared with lipase?Lipase?as the template,3-aminopropyltriethoxysilane and CDs as the functional monomer.The morphology of the prepared material was characterized by high resolution transmission electron microscopy.The prepared material was separately embedded in lipase and other protein solutions,and adsorbed much more lipase than other proteins,showing a higher selectivity to lipase.