A1 Refereed original research article in a scientific journal
Polyelectrolyte mediated nano hybrid particle as a nano-sensor with outstandingly amplified specificity and sensitivity for enzyme free estimation of cholesterol
Authors: Chebl Mazhar, Moussa Zeinab, Peurla Markus, Patra Digambara
Publisher: ELSEVIER SCIENCE BV
Publication year: 2017
Journal: Talanta
Journal name in source: TALANTA
Journal acronym: TALANTA
Volume: 169
First page : 104
Last page: 114
Number of pages: 11
ISSN: 0039-9140
eISSN: 1873-3573
DOI: https://doi.org/10.1016/j.talanta.2017.03.070
Abstract
As a proof of concept, here it is established that curcumin integrated chitosan oligosaccharide lactate (COL) self assembles on silica nanoparticle surface to form nano hybrid particles (NHPs). These NHPs have size in the ranges of 25-35 nm with silica nanoparticle as its core and curcumin-COL as outer layer having thickness of 4-8 nm. The fluorescence intensity of these NHPs are found to be quenched and emission maximum is similar to 50 nm red shifted compared to free curcumin implying inner filter effect and/or homo-FRET between curcumin molecules present on the surface of individual nano hybrid particle. Although fluorescence of free curcumin is remarkably quenched by Hg2+/Cu2+ ions due to chelation through keto-enol form, the fluorescence of NHPs is unaffected by Hg2+/Cu2+ ion that boosts analytical selectivity. The fluorescence intensity is outstandingly enhanced in the presence of cholesterol but is not influenced by ascorbic acid, uric acid, glucose, albumin, lipid and other potential interfering substances that either obstruct during enzymatic reaction or affect fluorescence of free curcumin. Thus, NHPs outstandingly improve analytical specificity, selectivity and sensitivity during cholesterol estimation compared to free curcumin. The interaction between cholesterol and NHPs is found to be a combination of ground state electrostatic interaction through the free hydroxyl group of cholesterol along with hydrophobic interaction between NHPs and cholesterol and excited state interaction. The proposed cholesterol biosensor illustrates a wider linear dynamic range, 0.002-10 mmol L-1, (upper limit is due to lack of solubility of cholesterol) needed for biomedical application and better than reported values during enzymatic reaction. In addition, the NHPs are found to be photo-stable potentially making it suitable for simple, quick and cost-effective cholesterol estimation and opening an alternative approach other than enzymatic reaction using nano hybrid structure to tune analytical specificity, selectivity and sensitivity of probe molecule.
As a proof of concept, here it is established that curcumin integrated chitosan oligosaccharide lactate (COL) self assembles on silica nanoparticle surface to form nano hybrid particles (NHPs). These NHPs have size in the ranges of 25-35 nm with silica nanoparticle as its core and curcumin-COL as outer layer having thickness of 4-8 nm. The fluorescence intensity of these NHPs are found to be quenched and emission maximum is similar to 50 nm red shifted compared to free curcumin implying inner filter effect and/or homo-FRET between curcumin molecules present on the surface of individual nano hybrid particle. Although fluorescence of free curcumin is remarkably quenched by Hg2+/Cu2+ ions due to chelation through keto-enol form, the fluorescence of NHPs is unaffected by Hg2+/Cu2+ ion that boosts analytical selectivity. The fluorescence intensity is outstandingly enhanced in the presence of cholesterol but is not influenced by ascorbic acid, uric acid, glucose, albumin, lipid and other potential interfering substances that either obstruct during enzymatic reaction or affect fluorescence of free curcumin. Thus, NHPs outstandingly improve analytical specificity, selectivity and sensitivity during cholesterol estimation compared to free curcumin. The interaction between cholesterol and NHPs is found to be a combination of ground state electrostatic interaction through the free hydroxyl group of cholesterol along with hydrophobic interaction between NHPs and cholesterol and excited state interaction. The proposed cholesterol biosensor illustrates a wider linear dynamic range, 0.002-10 mmol L-1, (upper limit is due to lack of solubility of cholesterol) needed for biomedical application and better than reported values during enzymatic reaction. In addition, the NHPs are found to be photo-stable potentially making it suitable for simple, quick and cost-effective cholesterol estimation and opening an alternative approach other than enzymatic reaction using nano hybrid structure to tune analytical specificity, selectivity and sensitivity of probe molecule.
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