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Author Raj, Vidya ♦ Jaime, Ruiz ♦ Astruc, Didier ♦ Sreenivasan, K.
Source Sree Chitra Tirunal Institute for Medical Sciences & Technology
Content type Text
Publisher Biosensors & Bioelectronics
File Format PDF
Language English
Subject Domain (in DDC) Technology ♦ Medicine & health ♦ Diseases
Subject Domain (in MeSH) Diagnosis ♦ Analytical, Diagnostic and Therapeutic Techniques and Equipment
Subject Keyword Laboratory Diagnosis
Abstract Functionalized colloidal gold is widely used for qualitative and quantitative detection of specific analytes. We report here a novel modification of gold nanoparticles by digitonin, a glycoside used for precipitating membrane cholesterol. The specific molecular recognition of cholesterol by digitonin gold nanoparticles (DGNP), make it an attractive alternative to the existing enzymatic methods for cholesterol sensing. To enable cholesterol binding, we modified mercapto modified GNPs with digitonin, by a simple esterification reaction. The blue shift in the plasmon absorption spectra of DGNP with different cholesterol concentrations accompanied by a decrease in the absorbance is the principle applied here for the estimation. The observed size reduction followed by cholesterol binding is reasoned due to the enhanced hydophobicity of the surface which in turn expels the water layers associated with the particles prior to cholesterol binding. The method exhibited linearity between concentration of cholesterol and the corresponding absorbance of the plasmon peak, in the range of 160-600 ng/mL with a detection limit of 100 +/- 9 ng/mL. Other steroids did not show any binding affinity towards DGNP. The method depicted here has potential for development as an enzyme free sensor for cholesterol although many factors need to be addressed to transform it for assaying samples like blood. (C) 2011 Elsevier B.V. All rights reserved.
Education Level UG and PG
Learning Resource Type Article
Educational Framework Medical Council of India (MCI)
Volume Number 27
Issue Number 1
Page Count 4
Starting Page 197
Ending Page 200