Development of sugar chain-binding single-chain variable fragment antibody to adult T-cell leukemia cells using glyco-nanotechnology and phage display method

Optimized immobilization of single chain variable fragment antibody onto non-toxic fluorescent nanoparticles for efficient preparation of a bioprobe

Single-chain variable fragment antibody (scFv) is a small molecular weight antibody that can be used for both therapeutic and diagnostic purposes. To visualize the interaction with the target biomolecules, scFv must be labeled with fluorescent molecules. In this study, to achieve the efficient labeling of scFv, we developed scFv-fluorescent nanoparticle conjugates to utilize scFv as bioprobes. As fluorescent carriers, cadmium-free ZnS-AgInS2/ZnS core/shell nanoparticles were used, and scFv was immobilized onto the nanoparticles via the interaction of nickel ions on nitrilotriacetic acid and hexahistidine (His-tag) fused with scFv. UV-Vis, fluorescence spectra, NMR, and dynamic laser scattering were used to characterize the scFv immobilized fluorescent nanoparticles (scFv-FNPs). The amounts of scFv on FNPs were controlled by the concentration of scFv. The scFv-FNPs that were prepared were non-toxic and selectively bound to cancer cells. The scFv-FNPs could be used as bioanalytical tools, and the immobilization method described here is a promising method for labeling biomolecules with the His-tag.

Screening and Identification of a Specific Binding Peptide to Ovarian Cancer Cells from a Phage-Displayed Peptide Library

To select specific binding peptides for imaging and detection of human ovarian cancer. The phage 12-mer peptide library was used to select specific phage clones to ovarian cancer cells. After four rounds of biopanning, the binding specificity of randomly selected phage clones to ovarian cancer cells was determined by enzyme-linked immunosorbent assay (ELISA). DNA sequencing and homology analysis were performed on specifically bound phages. The binding ability of the selected peptides to SKOV3 cells was confirmed by fluorescence microscopy and flow cytometry. After four rounds of optimized biological panning, phage recovery was 34-fold higher than that of the first round, and the specific phage clones bound to SKOV3 cells were significantly enriched. A total of 32 positive phage clones were preliminarily identified by ELISA from 54 randomly selected clones, and the positive rate was 59.3%. S36 was identified as the clone with best affinity to SKOV3 cells via fluorescence microscopy and flow cytometry. A representative clone of OSP2, S36 is expected to be an effective probe for diagnosis and treatment of ovarian cancer.