Preparation Of Protein Molecularly Imprinted Polymers Based On Quantum Dots Labeling

In this paper,CdS quantum dots(CdS-QDs)were prepared in the aqueous phase which having functional groups modified on the surface.Sodium hexametaphosphate was used as stabilizer,and L-cysteine(L-cys),thioglycolic acid(TGA),urea(Urea)were used as surface modifiers,respectively.Under the optimization of experimental conditions,the quantum dots with excellent luminescence properties were prepared,and the fluorescence quantum yield was 12.2%measured by integrating sphere method.Under the certain conditions,the concentration of BSA and the fluorescence intensity(F)of the composite system(contained CdS quantum dots and protein)presented a good linear relationship.Secondly,the supramolecular assembly(CD-PPRs)was assembled with y-cyclodextrin(γ-CD)as host molecules and polyvinyl alcohol(Mw=6000)as guest molecules.The CD-PPRs were used as the pseudo-supports in molecular imprinting polymers(MIPs),which could maintain the three-dimensional structure of MIPs effectively and improve the the imprinting properties.FT-IR,TG and XRD characterization methods were used,we had fought that the mass ratio of y-CD and PVA6000 was 1:1 could obtain the CD-PPRs which had the higest thermal decomposition temperature.XRD characterization results indicated that a new peak appeared at 26＝8.40,demonstrating that the CD-PPRs were synthesized successfully.Finally,a facile and efficient strategy was designed which has the good conditions of the bluk and imprinting methods for preparing the MIPs.Acrylamied(AM)was used as functional monomer and N,N’-methytenebisacrylamide(MBA)was used as the cross-linker.Meanwhile,the assembly(CD-PPRs)was used as pseudo-supports,bovine serum albumin(BSA),bovine hemoglobin(BHb),ovalbumin(OVA)and lysozyme(LYZ)were used as template molecules,respectively.SEM analysis showed that there were obviously differences in the surface morphology of imprinted polymers which had different proteins as templates.It was found that the surface of MIPs added with CD-PPRs was rougher and the morphology of the MIPs was more obviously,indicating that CD-PPRs could maintain the integrity of template protein and the structure stability of imprinted holes.At the same time,the experiment also combined the coupling between BSA and CdS-QDs,and explored the influence of the amount of CD-PPRs-Ac on the adsorption properties of BSA-MEPs by fluorescence detection.It was found that 0.8 g CD-PPRs-Ac were added to the system,the fluorescence intensity of the protein residual in supernatant and CdS-QDs compound system was the lowest,and C-MIPs adsorption amount was the highest.Furthermore,QDs which modified by L-cys were added in the imprinting system,making the adsorption amount of CQ-MIPs further improved compared with C-MEPs.We also found that the adsorption of imprinted polymer was mainly controlled by chemical adsorption mechanism.The competitive adsorption experiments and polyacrylamide gel electrophoresis confirmed that MIPs and C-MIPs had specific adsorption capacity for template proteins.Multiple adsorption-elution experiments showed that the reusability of C-MIPs synthesized on the optimal experimental conditions could reach up to 80.9%.