Browsing by Author "Ali, Md. Azahar"
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- Electrochemical Urea Biosensor Based on Sol-gel Derived Nanostructured Cerium OxideAnsari, Anees A.; Ali, Md. Azahar; Malhotra, B. D. (World Scientific, 2012-04-18)Urease (Urs) and glutamate dehydrogenase (GLDH) have been co-immobilized onto a nanostructured–cerium oxide (Nano-CeO2) film deposited onto a indium-tin-oxide (ITO) coated glass substrate by dip-coating via sol-gel process for urea detection. This nanostructured film has characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscope (SEM) and electrochemical techniques, respectively. The particle size of the Nano-CeO2 film has been found to be 23 nm. Electrochemcial response (CV) studies show that Ur-GLDH/Nano-CeO2/ITO bioelectrode is found to be sensitive in the 10–80 mg/dL urea concentration range and can detect urea concentration upto 0.1 mg/dL level. The value of Michaelis–Menten constant (Km) estimated using Lineweaver–Burke plot found as 6.09 mg/dL indicates enhancement in the affinity and/or activity of enzyme attached to their nanobiocomposite. This bioelectrode retained 95% of enzyme activity after 6 months at 4°C.
- Fabrication of nanocrystalline CdS electrode via chemical bath deposition technique for application to cholesterol sensorDhyani, Hemant; Srivastava, Saurabh; Ali, Md. Azahar; Malhotra, B. D.; Sen, Prasenjit (IOP, 2012-04-18)A nanocystalline CdS electrode has been fabricated by chemical bath deposition (CBD) technique onto hydrolyzed indium tin oxide (ITO) coated glass substrate at 78°C for the immobilization of cholesterol oxidase (ChOx). The prepared Nano-CdS based electrode has been characterized using UV-visible, X-ray diffraction (XRD), Fourier transform-infrared (FTIR) and scanning electron microscopy (SEM). The ChOx/Nano-CdS/ITO bioelectrode shows the detection range of cholesterol from 50 to 400 mg/dl with improved sensitivity of 1.35 μA/mgdl−1/cm2, low detection limit (6.1 mg/dl) and low Km (0.45mM) value indicating strong enzyme (cholesterol oxidase)-matrix (CdS) affinity.
- Testing for BLV: Control, reduction, and elimination?Corl, Benjamin A.; Ali, Md. Azahar (Virginia State Dairymen's Association, 2023-10-01)
- Ultrarapid and ultrasensitive detection of SARS-CoV-2 antibodies in COVID-19 patients via a 3D-printed nanomaterial-based biosensing platformAli, Md. Azahar; Zhang, George Fei; Hu, Chunshan; Yuan, Bin; Jahan, Sanjida; Kitsios, Georgios D.; Morris, Alison; Gao, Shou-Jiang; Panat, Rahul (Wiley, 2022-12-01)Rapid detection of antibodies during infection and after vaccination is critical for the control of infectious outbreaks, understanding immune response, and evaluating vaccine efficacy. In this manuscript, we evaluate a simple ultrarapid test for SARS-CoV-2 antibodies in COVID-19 patients, which gives quantitative results (i.e., antibody concentration) in 10–12 s using a previously reported nanomaterial-based three-dimensional (3D)-printed biosensing platform. This platform consists of a micropillar array electrode fabricated via 3D printing of aerosolized gold nanoparticles and coated with nanoflakes of graphene and specific SARS-CoV-2 antigens, including spike S1, S1 receptor-binding domain (RBD) and nucleocapsid (N). The sensor works on the principle of electrochemical transduction, where the change of sensor impedance is realized by the interactions between the viral proteins attached to the sensor electrode surface and the antibodies. The three sensors were used to test samples from 17 COVID-19 patients and 3 patients without COVID-19. Unlike other serological tests, the 3D sensors quantitatively detected antibodies at a concentration as low as picomole within 10–12 s in human plasma samples. We found that the studied COVID-19 patients had higher concentrations of antibodies to spike proteins (RBD and S1) than to the N protein. These results demonstrate the enormous potential of the rapid antibody test platform for understanding patients' immunity, disease epidemiology and vaccine efficacy, and facilitating the control and prevention of infectious epidemics.