Investigation of the transformation of morphology, optical properties, and zeta potential of dumbbell-shaped gold nanorods upon Cr(vi) interaction was performed.

Jitendra Satija

Centre for Nanobiotechnology

Vellore Campus

Amitava Mukherjee

Chandra Sekaran N

Alex S.A

Khan M.A

Bhalerao G.M

Chakravarty S

Kasilingam B

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Analytical Methods

Hexavalent chromium can inflict several health issues in comparison to other oxidation states of chromium. Anisotropic gold nanorods (AuNRs) have size-tunable optical properties, and hence, the spectral shift noted with increasing Cr6+ concentrations can be employed for the development of a Cr6+ sensor. The present work involves the usage of BSA-coated AuNRs for Cr6+ detection in biological samples by utilizing hydrobromic acid. AuNRs, upon interaction with Cr6+, can exhibit decreased aspect ratio and transform to nanospheres for higher Cr6+ concentration, for which the color changes from violet to red can be visualized by bare eyes as well be characterized using transmission electron microscopy, UV–visible spectroscopy, and zeta potential analyzer. Cr6+ solutions prepared in phosphate buffer were acid digested to oxidize total chromium to Cr6+. A good linear calibration was noted for longitudinal surface plasmon peak shift (Δλmax) plotted against Cr6+ concentrations with a detection limit of 0.32 μM (R2 = 0.979; Range: 1–100 μM). The method was applied for Cr6+ spiked in artificial gastric and intestinal fluids and simulated blood plasma with good recovery percentages. Their applicability to test chromium internalized in Cr-tolerant bacterial cells and Cr bound to cell walls and chromium internalized in human cells was determined. Hence, the present method can be used as an alternative for Cr6+ analysis in biological matrices. © 2018 Elsevier B.V.

Journal of Molecular Liquids

Using gold nanorod-based colorimetric sensor for determining chromium in biological samples

Various strategies (single &amp; multi-pot) to synthesize dendrimer-coated metal nanoparticles and their exploration in various biomedical applications.

Journal of Materials Chemistry B

Dendrimer as a multifunctional capping agent for metal nanoparticles for use in bioimaging, drug delivery and sensor applications

An efficient detection method for Hg (II) ions at physiological pH (pH7.4) was developed using tween 20-modified gold nanorods (NRs) in the presence of dithiothreitol (DTT). Thiol groups (-SH) at the end of DTT have a higher affinity towards gold atoms, and they can covalently interact with gold NRs and leads to their aggregation. The addition of Hg(II) ions prevents the aggregation of gold NRs due to the covalent bond formation between the -SH group of DTT and Hg(II) ions in the buffer system. The changes in the longitudinal surface plasmon resonance peak of gold NRs were characterized using a UV-visible spectrophotometer. The absorption intensity peak of gold NRs at 679nm was observed to reduce after interaction with DTT, and the absorption intensity was noted to increase by increasing the concentration of Hg(II) ions. The TEM analysis confirms the morphological changes of gold NRs before and after addition of Hg(II) ions in the presence of DTT. Further, the aggregation and disaggregation of gold NRs were confirmed by particle size and zeta potential analysis. The developed method shows an excellent linearity (y=0.001x+0.794) for the graph plotted between the absorption ratio and Hg(II) concentration (1 to 100pM) under the optimized conditions. The limit of detection was noted to be 0.42pM in the buffer system. The developed method was tested in simulated body fluid, and it was found to have a good recovery rate.

Materials Science and Engineering: C

Anti-aggregation-based spectrometric detection of Hg(II) at physiological pH using gold nanorods

Convergence of localized surface plasmon resonance of metal nanoparticles with classical ELISA has emerged as a new class of immunoassays, i.e. plasmonic ELISA, enabling biocatalysis mediated ultrasensitive naked-eye detection of disease biomarkers.

RSC Advances

Plasmonic-ELISA: Expanding horizons

Current colorimetric detection techniques for metals using gold nanorods based on variations in the aspect ratio have been summarized.

Journal	Data powered by TypesetAnalytical Methods
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	1759-9660
Open Access	0