The Effect Of Protein Corona On Food Safety Detection Based On AuNPs Sensors And The Inquiry Of Solution Strategy

Food safety is a hot issue of concern to the people's livelihood in China.Compared with traditional methods,the probes and biosensors constructed by NMs have the advantages of simple operation,cheapness and wide applicability.It is the current research focus that improves the sensitivity and stability of analytical measurements and make them better and more widely used.Nanoprobes have very good application prospects,and their high specificity and accuracy are essential for target detection.Gold nanoparticles(AuNPs)have been extensively used as cores to modify the surface of various ligands to construct probes for sensing or imaging various types of analytes.The most commonly used are AuNPs-small molecule sensors,AuNPs-protein sensors,and AuNPs-aptamer sensors.However,the complex and uncontrollable interaction between NMs(including AuNPs)and biological matrices may affect their practical applications.Therefore,we believe that the formation of protein corona(PC)around AuNPs would inevitably affect the detection and accurate quantification of targets based on AuNPs.In this work,we systematically designed three types of typical noncovalent molecule-AuNPs sensors,choosing bovine serum albumin(BSA),bovine fibrinogen(Fg),hemoglobin(Hb),?-lactoglobulin(Lg),milk and Fetal bovine serum(FBS)as model proteins to construct PC,explore the influence of PC on the detection results of AuNPs sensors,and explore the strategies to solve these effects.Part 1:A noncovalent molecule-AuNPs sensors of AuNPs-dichlorofluorescein(AuNPs-DCF)was constructed,and protein of BSA,Fg,Hb,Lg,milk and FBS were selected model for constructing PCs.This study shows that the PC could cause the loss of detection signals and the increase of limits of detection(LOD)for AuNPs-DCF sensors as proposed.At 1 mg/mL concentration of proteins,the signals loss rates were83%(BSA),71%(Fg),70%(Hb),and 78%(Lg),the BSA has the greatest impact on AuNPs-DCF.The LOD increased from 3.39 nM(no protein)to 19.13 nm(BSA),11.25nM(Fg),11.89 nM(Hb),16.81 nM(Lg),17.31 nM(milk)and 37.43 nM(FBS).There was no direct relationship between the protein adsorption and the influence ability of proteins.And we attempted to correct the negative effect of PC to the AuNPs-DCF sensors using mathematical equations since the PEG backfilling strategy could not resolve the negative effects caused by PC.Part 2:AuNPs-Antibody-DNA(AuNPs-Ab-DNA)were constructed,and protein of BSA,Fg,Hb,Lg,milk and FBS were selected model for constructing PCs.PC could cause the loss of detection signals and the increase of LOD for this sensor.At 1 mg/mL concentration of proteins,the signals loss rates were 30%(BSA),44%(Fg),20%(Hb),and 43%(Lg),the Fg has the greatest impact on AuNPs-Ab-DNA.The LOD increased from 0.28 ng/mL(no protein)to 0.47 ng/mL(BSA),0.72 ng/mL(Fg),0.43 ng/mL(Hb),0.41 ng/mL(Lg),0.56 ng/mL(milk)and 0.56 ng/mL(FBS).There was no direct relationship between the protein adsorption and the influence ability of proteins.And we attempted to correct the negative effect of PC to the AuNPs-DCF sensors using mathematical equations since the PEG backfilling strategy could not resolve the negative effects caused by PC.Part 3:AuNPs-aptamer(AuNPs-Apt)was constructed,BSA,Fg,Hb,Lg,milk and FBS were selected to construct PCs.This study shows that the PC could cause the loss of detection signals and the increase of LOD for the AuNPs-Apt sensor.At 1 mg/mL concentration of proteins,the signals loss rates were 88%(BSA),87%(Fg),86%(Hb),and 82%(Lg),the BSA has the greatest impact on AuNPs-Apt.The LOD increased from 0.50 nM(no protein)to 2.69 nm(BSA),2.42 nM(Fg),3.65 nM(Hb),2.33 nM(Lg),2.42 nM(milk)and 3.76 nM(FBS).There was no direct relationship between the protein adsorption and the influence ability of proteins.When PC was present,the binding constants(K_a)and binding sites(n)of AuNPs and aptamer were reduced.In addition,we attempted to correct the negative effect of PC to the AuNPs-Apt sensors using mathematical equations since the PEG backfilling strategy could not resolve the negative effects caused by PC.This work demonstrates the negative effects of PC formation on detection results of noncovalent molecule-AuNPs sensors,it would cause false results and unavailability of related production,emphasizing the importance of avoiding PC effects in target detection.