A gold nanoparticle-single-chain fragment variable antibody as an immunoprobe for rapid detection of morphine by dipstick. Issue 3 (4th January 2018)

• Record Type: Journal Article
• Authors: Gandhi, Sonu; Banga, Ivneet; Maurya, Pawan Kumar; Eremin, Sergei A.
• Is Part Of: RSC advances. Volume 8:Issue 3(2018)
• Page Start: 1511
• Page End: 1518
• Publication Date: 2018-01-04
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra12810j
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Dipstick device developed on the principle of lateral flow using gold nanoparticles for analysis of morphine in urine by morphine/scFv/immunoprobe. Abstract : Gold nanoparticle (AuNP)-based optical assays are of significant interest since the molecular phenomenon can be examined easily with change in the color of AuNPs. Herein, we report the development of a dipstick using a AuNP-labeled single-chain fragment variable (scFv) antibody for the detection of morphine. The scFv antibodies for morphine were developed using phage display-based antibody library. Immunoglobulin variable regions of heavy ( V H )- and light ( V L )-chain genes were connected via a glycine–serine linker isolated from murine immune repertoire and cloned into the expression vector pIT2. The scFv was produced in Escherichia coli HB2151, yielding a functional protein with a molecular weight of approximately 32 kDa. The morphine scFv was labeled with gold nanoparticles and used as an optical immunoprobe in a dipstick. The competitive dipstick assay characterized the ability of the scFv antibody to recognize free morphine. The detection range was 1–1000 ng mL −1 with a limit of detection (LOD) of 5 ng mL −1 under optimal conditions, and the IC50 value was 14 ng mL −1 for morphine. The developed optical dipstick kit of scFv antibody was capable of specifically binding to free morphine and its analogs in a solution in less than 5 min and could be useful for on-site screening of a real sample in blood, urine, and saliva.