100 L/well TMB substrate was added and incubation was carried out for enzymatic reaction up to 15 minutes at RT. belong to a class of drugs known as opioids. Although BMS-265246 heroin and morphine drugs have been used for the treatment of pain and other symptoms, their use is usually associated with far more accidental overdoses and fatal poisonings than any other controlled material.1 WHO data suggest that developing countries only accounted for 6% of global opioid consumption while 6 developed countries consumed for 79% of global morphine.2 A report by the international narcotics control table (INCB) confirmed comparable global inclinations of opioid convenience.3 Indeed Morphine is very restricted or absent in many low- and middle-income countries, such as India.4 Recent surveys report that nearly one million individuals abuse heroin in the United States. Indeed, heroin is one of the most commonly co-abused drugs with cocaine, second only to ethanol. Heroin is usually associated BMS-265246 with far more accidental overdoses and fatal poisonings than any other controlled material.5 Heroin shares the core structure of morphine, with the addition of two acetyl groups. After ingestion, heroin gets deacetylated to monoacetyl morphine (MAM), and then to morphine which is usually then metabolized to morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) and finally to Nedd4l normorphine.6 Detection of heroin and MAM in the blood can be difficult because of its short half-life and short detection time. In contrast, morphine excreted in urine has been used as a specific marker of heroin abuse as it is usually detectable in urine for several hours after BMS-265246 heroin uptake.7 Several chromatographic techniques such as thin-layer chromatography (TLC), gas-liquid chromatography (GLC), mass spectrometry (MS) and high-performance liquid chromatography (HPLC) have been utilized for the qualitative/quantitative detection of these drugs but these analytical methods are very time consuming, expensive, require many cleanup actions, trained staff and also not applicable to on-site monitoring.8,9 To overcome this situation, various biosensors have been developed for narcotic drugs pesticides, and cancer detection.10-15 Bacterial luciferases, a bioluminescent enzyme utilized for the detection of heroin esterase and morphine dehydrogenase up to 89 ng/mL and 2. 0 ng/mL for heroin and morphine respectively.16 Several groups have generated antibodies against morphine and its derivatives for enzyme immunoassay (EIA) applications.17-19 Polyclonal antibodies were designed for M-3-G (morphine-3-glucuronide).20 To develop an enzyme-based sensor for narcotic drugs, antibodies shall be prepared in such manner that it can provide broad specificity. The main theory is the competitive inhibition between labeled and unlabeled drug for antigen binding sites in the antibody. The metabolic pathway of heroin and its analogs last for 9 to 38 moments, therefore, it is important to detect these metabolites with a broad range of antibody.21 Various immunoassays were developed to detect structurally related opiates such as MAM, morphine, codeine, hydrocodone, and hydromorphone but show less or no cross-reactivity with oxycodone, oxymorphone and synthetic opioids and analgesics.22,23 Another essential path is to design suitable hapten-protein conjugate that can be utilized to raise polyclonal antibodies with broad specificity. In our previous studies, we BMS-265246 conjugated hapten (MAM) with the carrier protein (BSA) and developed group selective antibodies for competitive fluorescence assay.24,25 To overcome the phenomenon of quenching in the fluorescence based assay, we have used developed lateral flow dipstick assay (LFDA) by using anti-morphine antibodies from egg yolk and phage display (scFv) technique. The polyclonal antibodies (IgY) from egg yolk and recombinant antibodies were labeled with gold nanoparticles separately. The sensitivity of the LFDA was found BMS-265246 to be 10 ng/mL for IgY and 15 ng/mL for scFv that does not fulfill the objective to develop the strong and sensitive assay.25,26 Electrochemical sensing has tremendous applications in terms of increasing sensitivity of the developed assay.27 Single-walled carbon nanotubes (SWCNTs) possesses excellent conductance and surface functionalization properties that we utilized for the detection of various biomolecules.28 Our group has developed an immunoassay for label-free detection of morphine by liquid gated-field effect transistor (LG-FET) based sensor with the limit of detection.