Electrochemically driven optical and SERS immunosensor for the detection of a therapeutic cardiac drug

Madeeha Chaudhry; Dong-Kwon Lim; Jeon Woong Kang; Zahid Yaqoob; Peter So; Muhammad Fahad Bhopal; Minqiang Wang; Raheel Qamar; Arshad Saleem Bhatti

doi:10.1039/d1ra07680a

Electrochemically driven optical and SERS immunosensor for the detection of a therapeutic cardiac drug

RSC Adv. 2022 Jan 20;12(5):2901-2913. doi: 10.1039/d1ra07680a. eCollection 2022 Jan 18.

Authors

Madeeha Chaudhry^{1

2}, Dong-Kwon Lim³, Jeon Woong Kang⁴, Zahid Yaqoob⁴, Peter So^{4

5

6}, Muhammad Fahad Bhopal¹, Minqiang Wang⁷, Raheel Qamar⁸, Arshad Saleem Bhatti^{1

9}

Affiliations

¹ Centre for Micro and Nano Devices, Department of Physics, COMSATS University Islamabad Tarlai Kalan Islamabad 45550 Pakistan asbhatti@comsats.edu.pk.
² Department of Biosciences, International Islamic University H-10, Islamabad Capital Territory 44000 Islamabad Pakistan.
³ KU-KIST Graduate School of Converging Science and Technology, Korea University Seoul Korea.
⁴ Laser Biomedical Research Center, G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology Cambridge MA 02139 USA.
⁵ Department of Mechanical Engineering, Massachusetts Institute of Technology Cambridge MA 02139 USA.
⁶ Department of Biological Engineering, Massachusetts Institute of Technology Cambridge MA 02139 USA.
⁷ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, Faculty of Electronic and Information Engineering, Xi'an Jiaotong University Xi'an 710049 China.
⁸ Science &Technology Sector, ICESCO Rabat Morocco.
⁹ Virtual University of Pakistan M.A Jinnah Campus Lahore Pakistan.

Abstract

Cardiovascular diseases pose a serious health risk and have a high mortality rate of 31% worldwide. Digoxin is the most commonly prescribed pharmaceutical preparation to cardiovascular patients particularly in developing countries. The effectiveness of the drug critically depends on its presence in the therapeutic range (0.8-2.0 ng mL^-1) in the patient's serum. We fabricated immunoassay chips based on QD photoluminescence (QDs-ELISA) and AuNP Surface Enhanced Raman Scattering (SERS-ELISA) phenomena to detect digoxin in the therapeutic range. Digoxin levels were monitored using digoxin antibodies conjugated to QDs and AuNPs employing the sandwich immunoassay format in both the chips. The limit of detection (LOD) achieved through QDs-ELISA and SERS-ELISA was 0.5 ng mL^-1 and 0.4 ng mL^-1, respectively. It is demonstrated that the sensitivity of QDs-ELISA was dependent on the charge transfer mechanism from the QDs to the antibody through ionic media, which was further explored using electrochemical impedance spectroscopy. We demonstrate that QDs-ELISA was relatively easy to fabricate compared to SERS-ELISA. The current study envisages replacement of conventional methodologies with small immunoassay chips using QDs and/or SERS-based tags with fast turnaround detection time as compared to conventional ELISA.