Biopanning For The Selection Of Peptides With High Specificity To Arsenic And Arsenic Sensing

Phage display peptide library technique is a powerful tool for the screening of peptide ligand with high affinity for heavy metals.The selected peptide can be further used for the detection of a certain heavy metals.Arsenic is a highly toxic element that is abundant in the environment as anthropogenic sources,and the overdose intake or excessive contact will be harmful to human health.Therefore,it is of great importance for the environment and human health to develop accurate and selective detection method for trace level of arsenic.In this paper,different metal ions were immobilized on y-Fe2O3-IDA affinity resins for the interaction with the heptapeptide phage library.By several rounds of positive biopanning against target As(?)and negative biopanning against foreign metal ions,phages which can bind with foreign metal ions were eliminated for the guarantee of selectivity,while phages which only bind with As(?)were kept and enriched during the positive screening.After biopanning procedure,a certain amount of phage clones were randomly selected and sequenced by DNA sequencing.The thus obtained As(?)binding peptide sequences of the corresponding phage were identified and analyzed by ELISA.A peptide with high affinity and selectivity for As(?)(sequence:T-Q-S-Y-K-H-G)was finally selected as the best As(?)binding peptide for the development of the following As(?)sensing procedure.By using this peptide as recognition element and unmodified AuNPs as sensing probe,a sensitive and selective sensing approach for As(?)was thus developed.The rational designed peptide T-Q-S-Y-K-H-G-C can induce the aggregation of AuNPs,whereas As(?)competitively bind to the peptide thus prevent the aggregation.Under optimized conditions,a limit of detection of 0.0540 ?mol L-1 and a linear range of 0.195-0.600 ?mol L-1 were achieved together with a RSD of 0.5%,which meet the need for practical analysis.