Neha Batra

ZnO-CuO composite matrix based reagentless biosensor for detection of total cholesterol.

An efficient reagentless biosensor for determination of free cholesterol and total cholesterol has been realized using a ZnO-CuO composite matrix grown onto ITO coated corning glass substrates by pulsed laser deposition (PLD) technique. The inclusion of CuO in ZnO matrix successfully introduces redox property and provides enhanced electron communication features. The optimized ZnO-CuO composite matrix has been used for development of ChOx/(ZnO-CuO)/ITO/glass and (ChEt-ChOx)/(ZnO-CuO)/ITO/glass bioelectrodes used for selective detection of free and total cholesterol respectively in the range of 0.12-12.93 mM and 0.5-12 mM without using any external mediator. The fabricated biosensors exhibit high sensitivity of about 680 µA mM(-1) cm(-2) and 760 µA mM(-1) cm(-2) towards free cholesterol and total cholesterol respectively with response time of 5 s, along with high shelf life. The results are encouraging and show the promising application of the ZnO-CuO composite matrix for the realization of reagentless integrated implantable biosensor.

Laser ablated ZnO thin film for amperometric detection of urea

Zinc oxide (ZnO) thin films deposited onto indium tin oxide (ITO) coated corning glass substrates using pulsed laser deposition (PLD) technique at two different oxygen pressures (50 mT and 100 mT) have been used as efficient matrix for realization of efficient urea biosensors after immobilization of urease (Urs) enzyme onto ZnO film surface. The bioelectrode Urs/ZnO/ITO/glass having ZnO matrix grown at 100 mT is found to be exhibiting an enhanced sensitivity of 36 μΑ mΜ−1 cm−2 for urea over a wide detection range of 5–200 mg/dl. The relatively low value of Michaelis–Menten constant (Km = 0.82 mM) indicates high affinity of the immobilized urease towards the analyte (urea). The prepared sensor exhibits high selectivity towards detection of urea and retains 90% of its activity for more than 12 weeks. The observed enhanced response characteristics of bioelectrode is attributed to the growth of highly c-axis oriented ZnO thin film by PLD at 100 mT oxygen pressure with desired rough and porous surface morpholo...

Al:ZnO thin film: An efficient matrix for cholesterol detection

Al doped ZnO thin film (Al:ZnO) has been realized as a potential matrix for the development of efficient cholesterol biosensor. The correlation between the structural and electrical properties of ZnO thin film with varying Al doping concentration (1% to 5%) and their cyclic voltammetric (CV) response has been studied. 2% Al doped ZnO films were found to give the best CV response and were further utilized for immobilization of cholesterol oxidase (ChOx) to detect cholesterol. Amperometric and photometric studies reveal that the prepared bioelectrode based on 2% Al doped ZnO matrix (ChOx/Al:ZnO/Pt/glass) is highly sensitive (sensitivity = 173 μAmM−1 cm−2) to the detection of cholesterol in the wide range from 0.6–12.9 mM (25–500 mg/dl). A relatively low value of enzymes kinetic parameter (Michaelis menten constant, 2.53 mM) indicates enhanced affinity of the immobilized ChOx toward cholesterol. The prepared bioelectrode is found to be exhibiting high shelf life (10 weeks) having negligible interference wit...

Efficient detection of cholesterol using ZnO thin film based matrix

Zinc oxide (ZnO) thin films grown by pulsed laser deposition on indium-tin-oxide (ITO)-coated corning glass are used to immobilise cholesterol oxidase (ChOx) and for cholesterol detection. Cyclic voltammetric studies indicate that the ChOx/ZnO/ITO/glass bioelectrode is sensitive to the detection of cholesterol in 25–500 mg/dL range. A relatively low value of enzymes kinetic parameter (Michaelis–Menten constant; 1.92 mM) indicates enhanced enzyme affinity of ChOx to cholesterol. The prepared bioelectrode is found to be exhibiting high shelf life of 12 weeks having negligible interference with the presence of other biomolecules present in human serum indicating promising application of ZnO thin films for cholesterol sensing.