Browsing by Author "Ali, Md. Azahar"

Now showing 1 - 6 of 6
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    Advancing Multi-Ion Sensing with Poly-Octylthiophene: 3D-Printed Milker-Implantable Microfluidic Device
    Ali, Md. Azahar; Kachoueim, Matin Ataei (Wiley-VCH, 2024)
    On-site rapid multi-ion sensing accelerates early identification of environmental pollution, water quality, and disease biomarkers in both livestock and humans. This study introduces a pocket-sized 3D-printed sensor, manufactured using additive manufacturing, specifically designed for detecting iron (Fe²⁺), nitrate (NO₃⁻), calcium (Ca²⁺), and phosphate (HPO₄²⁻). A unique feature of this device is its utilization of a universal ion-to-electron transducing layer made from highly redox-active poly-octylthiophene (POT), enabling an all-solid-state electrode tailored to each ion of interest. Manufactured with an extrusion-based 3D printer, the device features a periodic pattern of lateral layers (width = 80 μm), including surface wrinkles. The superhydrophobic nature of the POT prevents the accumulation of nonspecific ions at the interface between the gold and POT layers, ensuring exceptional sensor selectivity. Lithography-free, 3D-printed sensors achieve sensitivity down to 1 ppm of target ions in under a minute due to their 3D-wrinkled surface geometry. Integrated seamlessly with a microfluidic system for sample temperature stabilization, the printed sensor resides within a robust, pocket-sized 3D-printed device. This innovation integrates with milking parlors for real-time calcium detection, addressing diagnostic challenges in on-site livestock health monitoring, and has the capability to monitor water quality, soil nutrients, and human diseases.
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    Electrochemical Urea Biosensor Based on Sol-gel Derived Nanostructured Cerium Oxide
    Ansari, 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.
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    Fabrication of nanocrystalline CdS electrode via chemical bath deposition technique for application to cholesterol sensor
    Dhyani, 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.
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    Functionalized Graphene-Based Biosensors for Early Detection of Subclinical Ketosis in Dairy Cows
    Chick, Shannon; Kachouei, Matin Ataei; Knowlton, Katharine; Ali, Md. Azahar (American Chemical Society, 2024-08-22)
    Precision livestock farming utilizing advanced diagnostic tools, including biosensors, can play a key role in the management of livestock operations to improve the productivity, health, and well-being of animals. Detection of ketosis, a metabolic disease that occurs in early lactation dairy cows due to a negative energy balance, is one potential on-farm use of biosensors. Betahydroxybutyrate (βHB) is an excellent biomarker for monitoring ketosis in dairy cows because βHB is one of the main ketones produced during this metabolic state. In this report, we developed a low-cost, Keto-sensor (graphene-based sensor) for the detection of βHB concentrations in less than a minute. On this device, graphene nanosheets were layered onto a screen-printed electrode (SPE), and then, a stabilized enzyme (beta-hydroxybutyrate dehydrogenase, NAD⁺, and glycerol) was used to functionalize the graphene surface enabled by EDC−NHS conjugation chemistry. The Keto-sensor offers an analytical sensitivity of 10 nM and a limit of detection (LoD) of 0.24 nM within a detection range of 0.01 μM−3.00 mM. Spike testing indicates that the Keto-sensor can detect βHB in serum samples from bovines with subclinical ketosis. The Keto-sensor developed in this study shows promising results for early detection of subclinical ketosis on farms.
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    Testing for BLV: Control, reduction, and elimination?
    Corl, Benjamin A.; Ali, Md. Azahar (Virginia State Dairymen's Association, 2023-10-01)
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    Ultrarapid and ultrasensitive detection of SARS-CoV-2 antibodies in COVID-19 patients via a 3D-printed nanomaterial-based biosensing platform
    Ali, 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.