| Detection of biological molecules,often involved in the biochemistry and medical science,is an important indicator of disease diagnosis and treatment,as well as the conventional analysis project of food inspection and environmental monitoring.With the increasing demands of modern biological analysis technology,the exploration of high sensitivity and selectivity detection method is becoming a new challenge for biological sensing technology.Due to its unique structure and properties,nanomaterials provide the possibility for the development of biosensors with high sensitivity and miniaturization.At present,molecular recognition nanomaterials has been widely investigated.Unfortunately,there are still some problem exist.Firstly,molecular recognition process is needed to be transformed into a visual signal,while traditional fluorescence labeling methods are expensive.By combining the stimulus response material with the photonic crystal structure,photonic crystal biochemical sensing materials with fast response and self-reporting properties can be developed.Traditional photonic crystal sensing materials are inverse opal structures prepared by using 3D photonic crystals as templates.The preparation procedure is complicated.Secondly,the selectivity of many molecular recognition nanomaterials are not desirable.Thirdly,the adsorption capacity and selectivity of the nanomaterials are widely studied.However,the study of adsorption mechanism of nanomaterials is inadequate.Based on above-mentioned situation,the preparation of recognition nanomaterials and its application in biological molecular recognition were studied in this paper,the contents and results are as follows:(1)Temperature-responsive polymers were prepared by RAFT polymerization.Linear polymers were employed to the separation of the protein for the first time,and nanomaterials with high selectivity to the target protein was developed.The results showed that the selectivity of the target protein was enhanced because of the flexible conformation of linear polymers,and thus the lysozyme was successfully separated from the egg white.Furthermore,the reversible adsorption and release of the target protein was achieved by adjusting the temperature,without the damage of the secondary sructure of the protein.(2)Combining the linear structure with crosslinked hydrogel,the hydrogel with linear polymer brush was prepared by RAFT polymerization.As a result,a new type of nanomaterial with high selectivity was developed.The results showed that modified hydrogel possessed high adsorption capacity and selectivity to target protein.The lysozyme was separated from the egg white by this modified hydrogel.By comparing adsorption properties of three kinds of hydrogel with different structures,the adsorption mechanism of the hydrogel over protein was studied.(3)An opal close-packed photonic crystal is prepared for lysozyme detection by naked-eye.This photonic crystal is fabricated via assembly of monodispersed silica particles grafted with linear polymer ligands.The proposed photonic crystal displays a maximum red shift of 23 nm in response to 144 ?M lysozyme,accompanied by the structure color change from blue to green.With this sensory system,direct,ultra-sensitive(as low as 0.36 ?M)and selective detection of lysozyme with a broad concentration range varying from 0.36 ?M to 144 ?M in aqueous media is achieved without the use of label techniques and expensive instruments.(3)Combining the surface imprinting technique with photonic crystal,imprinted photonic crystal sensing materials with signal self-reporting properties can be developed.Protein imprinted silica spheres were prepared in the aqueous solution,using silica nano-spheres as matrix.The surface imprinted silica were assembled into photonic crystal array by the vertical sedimentation self assembly method.The reflection of the molecular imprinted colloidal array(MICA)red shifted by 23 nm in response to 15 ?M Hb at pH 7.0,and the detection limit was 0.075 ?M.With the increasing concentration of the target,the structural color of the imprinted photonic crystal changed from green to blue,which meant the concentration of the target can be detected by the red shift of reflection.Therefore,the detection cost is low,and it is simple,reliable and cost effective.(4)In order to improve the sensing properties of imprinted photonic crystal sensing materials,molecularly imprinted hollow spheres(MIHSs)were prepared.Afterwards,the MIHSs were successfully assembled into a closely-packed 3D colloidal array.The molecularly imprinted hollow sphere array(MIHSA)can selectively recognize Hb.As the concentration of Hb increased,the structure color of the MIHSA changed from blue togreen,and turn to white finally with maximum red shift for 43 nm.The MIHSA showed promising potential for the naked-eye detection of target Hb.(5)In order to extend the target species that can be detected by the imprinted photonic crystal array,sensing materials with high selectivity to environmental stimuli were prepared.The reflection of the molecular imprinted colloidal array(MICA)red shifted by22 nm in response to 500 ?M of estradiol,and the detection limit was 5 ?M.(6)The extraction of Hb,estradiol from samples was realized using imprinted hollow spheres.Compared to the surface imprinted silica(SIS),the imprinted hollow spheres had good recognition and fast adsorption-desorption dynamics for the target molecule.This study demonstrates the potential of molecularly imprinted hollow spheres for the selective removal of macromolecules. |
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