Disposable Immunosensor Based on Electrochemiluminescence for Ultrasensitive Detection of Ketamine in Human Hair

Abstract

An ultrasensitive disposable immunosensor based on a gold nanoparticles (AuNPs)/indium tin oxide (ITO) substrate has been constructed to detect ketamine (KET) conveniently. In this study, we obtained a AuNPs/ITO basic electrode by only a two-step ecofriendly drip-coating procedure. The self-assembled monolayers of AuNPs were used as a hetero-bifunctional cross-linker and activator, respectively. Ketamine antibody was used as a biorecognition determinant and immobilized onto the AuNPs/ITO through electrostatic interaction or Au−S or Au−N bonds. The architectures of AuNPs/ITO were characterized by transmission electron microscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy mainly. Electrochemiluminescence (ECL) was used to monitor the specific immune response between the antigen and antibody by measuring changes of intensity in the process of ECL. When the immune complex was incubated on the electrode, it blocked the electron communication and mass transfer, and the ECL signal was quenched. According to the quenched ECL signal, the quantification of KET can be realized. Under optimal conditions, the immunoassay showed a linear range from 10 to 100 pg/g. The low detection limit is 5.73 pg/g. The sensor has been applied to detect ketamine in human hair successfully. In addition, the immunosensor has excellent selectivity, outstanding reproducibility, and acceptable stability. What's more, the immunosensor exhibits low-cost, simplicity, small sample consumption, and easy miniaturization, which allows it to be integrated into portable platforms to be utilized on the site of crime easily.

Graphene-Based Electrochemical Sensors for Psychoactive Drugs

“…Ketamine is another analgesic drug with wide application in the medical field [69,70]. However, the abuse of ketamine is increasing to the point that it has become a major concern, not only due to its abuse for recreational purposes [71,72], but also because this colorless, odorless and tasteless drug facilitates sexual assaults when it is added to drinks [73,74]. Miniaturized nanomaterial-based sensors could provide fast, portable detection, to help monitor drug abuse in any situation.…”

Does the salt really matter? Impact of the counterion upon ECL signal

“…The amine functionality is widely known within the electrochemical field to gift a number of compounds the necessary electroactivity required to be suited for electrochemical detection. 22,[26][27][28][29][30][31][32][33][34][35][36] Alongside sister tropane alkaloid atropine and fellow alkaloid species quinine and cocaine, scopolamine is observed to undergo an irreversible oxidation, through the oxidative N-dealkylation mechanism previously described. 17 To the best of our knowledge no reports concerned with the impact upon the substitution of different counterions exist to date.…”

Aggregation-Induced Electrochemiluminescence Immunosensor Based on 9,10-Diphenylanthracene Cubic Nanoparticles for Ultrasensitive Detection of Aflatoxin B1

“…As shown in Figure 3A, bare GCE showed a pair of reversible redox peaks at 0.22 and 0.17 V (curve a), and a significantly decreased current signal was displayed after modified with DPA CNPs (curve b), which is mainly due to the decreased electron transfer and the impeded permeability of the redox probe from DPA CNPs to electrode. 48 Continuous weaker peak currents were observed after modifying with PEI (curve c), GA (curve d), Ab 1 (curve e), BSA (curve f), and AFB 1 (curve g), which may originate from the partial insulation of the PEI polymer, successful assembly of GA, electron-blocking layer of protein, 49 steric effect of the inert electron layer in BSA, 50 and the insulation hindrance of the antigen−antibody complex, 51 respectively, which illustrate that the sensor was successfully assembled.…”