Chemiluminescence based immunoassay for the detection of heroin and its metabolites

Introduction: Continuous use of opiates causes drug-related illnesses, which poses an alarming situation to develop sensitive detection platform. In this study, a highly sensitive and reliable chemiluminescence immunoassay (CI) has been developed for the detection of heroin and its major metabolites in spiked urine samples. Methods: To develop robust immunoassay, monoacetyl morphine-bovine serum albumin (MAM-BSA) conjugate was synthesized and characterized thoroughly by physicochemical techniques. The anti-MAM antibodies were developed, labeled with horseradish peroxidase (HRP) and immunoassay was developed to detect the presence of target drug in spiked urine samples. Results: A competitive CI was developed, where heroin, MAM, morphine, and codeine concentration were ranged from 0-1000 ng/ mL in spiked urine samples and limit of detection were 80, 95, 90, 75 pg/ mL. Conclusion: The developed CI is highly sensitive, specific, point of care, cost-effective and can be used as a routine technique for quantitative analysis for screening of narcotic drugs

A gold nanoparticle-single-chain fragment variable antibody as an immunoprobe for rapid detection of morphine by dipstick

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.Central Forensic Science Laboratory (CFSL), Chandigarh, IndiaDepartment of Science and Technology (DST), New Delhi, IndiaAmity Univ, Inst Biotechnol, Sect 125, Noida 201313, IndiaUniv Fed Sao Paulo, Neurosci Sao Paulo, BR-04023900 Sao Paulo, BrazilMoscow MV Lomonosov State Univ, Fac Chem, Leninsky Gory 1, Moscow 119991, RussiaUniv Fed Sao Paulo, Neurosci Sao Paulo, BR-04023900 Sao Paulo, BrazilDepartment of Science and Technology (DST), New Delhi, India: ECR/000075Web of Scienc