Impurity-induced peroxidase mimicry of nanoclay and its potential for the spectrophotometric determination of cholesterol
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A green version of the “Fe” impurity-induced peroxidase mimicry exhibited by simple and cheap substrate “nanoclay (NC)” along with the highly sensitive amperometric and spectrophotometric determination of cholesterol is demonstrated. The “Fe” impurity can act as the catalyst center for hydrogen peroxide reduction similar to the horseradish peroxidase (HRP)-catalyzed reaction. The Michaelis–Menten constant for the NC-catalyzed reaction is found to be lower than that of the HRP-catalyzed reaction indicating high affinity for the substrate. The NC-modulated peroxidase-like catalytic activity originates from the electron transfer between the reducing substrate in the catalyst center and H2O2 with the intermediate generation of hydroxyl radicals. The peroxidase mimicry is successfully applied for the low-potential electrochemical detection of H2O2 (linear detection range 1.96–10.71 mM, R 2 = 0.97). The H2O2 sensing platform is further modified with cholesterol oxidase (CHOx) for the spectrophotometric (linear detection range 50–244 μM, R 2 = 0.99) and amperometric detection of cholesterol (linear detection range 0.099–1.73 mM, R 2 = 0.998).
KeywordsMicro/nano structures Nanoclay Peroxidase mimicry H2O2 detection Cholesterol detection
We acknowledge the financial support from the project CSC0134 (M2D). Mr. K. Aneesh is thankful to CSIR, New Delhi, India, for the award of Senior Research Fellowship. The authors also acknowledge the help received from Mr. J. Kennedy, Central Instrumentation Facility, CECRI, for XPS analysis.
Compliance with ethical standards
The authors declare that they have no conflict of interest. All procedures performed in studies using human blood serum were in accordance with the ethical standards of the institution, and informed consent of all individual participants were taken for blood serum analysis.
- 4.Aneesh K, Vusa CSR, Berchmans S. Dual enzyme mimics exhibited by ITO nanocubes and its application in spectrophotometric and electrochemical sensing. Analyst. 2016;141(13):4024-8. doi: 10.1039/C6AN00811A.
- 9.Ghosh AB, Saha N, Sarkar A, Dutta AK, Biswas P, Nag K et al. Morphological tuning of Eu2O2S nanoparticles, manifestation of peroxidase-like activity and glucose assay use. New J Chem. 2016.Google Scholar
- 20.Shi W, Fan H, Ai S, Zhu L. Honeycomb-like nitrogen-doped porous carbon supporting Pt nanoparticles as enzyme mimic for colorimetric detection of cholesterol. Sensors and Actuators B: Chemical. 2015.Google Scholar
- 29.Myant NB. The biology of cholesterol and related steroids. Butterworth-Heinemann; 2014.Google Scholar
- 37.Josephy PD, Eling T, Mason RP. The horseradish peroxidase-catalyzed oxidation of 3, 5, 3', 5'-tetramethylbenzidine. Free radical and charge-transfer complex intermediates. J Biol Chem. 1982;257(7):3669–75.Google Scholar