Application Of An M13 Bacteriophage Display For Detection Of Iron And The HIV-1 P24 Protein

Phage display,as a significant technique,has been widely applied in biology and related area,such as therapeutic development and diagnostics,molecular imaging,immunoassay,nanomaterial.An M13 bacteriophage was engineered to display a tyrosine residue on gp8.The concentration of iron and its relavance to the count of plaque was found and applied for the detection of ferric and ferrous ions.For the detectin of ferric ions,a calibration curve ranging from 200 nmol/L to 8 ?mol/L with a detection limit of 58 nmol/L was acquired.Meanwhile,for ferrous ions,a calibration curve ranging from 800 nmol/L to 8 ?mol/L with a detection limit of 641.7 nmol/L was acquired.Besides,Ni~2+,Pb~2+,Zn~2+,Mn~2+,Co~2+,Ca~2+,Cu~2+,Cr~3+,Ba~2+,and K~+ were tested as interference to identify the specificity of that method.This biosensor would have plenty of room in iron fast detection for its specificity,sensitivity,no need for instruments,under particular circumstances,such as factory.HIV-1 P24 antigen has an important significance role in early detection at window period.In this study,single chain antibody against P24 was displayed as fusion protein on gp3 and was used for the HIV-1 P24 antigen detection using phage-ELISA.To perform phage-ELISA,p24 gene was cloned with PCR and ligated to prokaryotic expression vector pET-28 a.The genetic engineering bacteria was constructed when the vector was transferred into E.coli BL21.P24 fusion protein with His-tag was expressed in E.coli BL21 with IPTG,and the concentration of P24 protein reaches 1.8 mg/mL after the purification through Ni-chelating affinity chromatography and the ultrafiltration.For the detection of P24 antigen with phage-ELISA,a detection limit of 93.5 ng/mL was acquired.