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.

Chandra Sekaran N

Centre for Nanobiotechnology

Vellore Campus

Amitava Mukherjee

Alex S.A

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

Journal of Molecular Liquids

Gold nanorods (AuNRs) have distinctive opto-electronic properties, which facilitate their exploitation in various fields, especially biology and medicine. However, their interaction with the biomolecules in the physiological system can cause the formation of a protein corona, composing of a soft and hard layer, which ultimately alters the physiochemical properties, toxicity, and fate of the nanoparticles. Thus, the formation and composition of protein corona on three differently functionalized AuNRs [CTAB-AuNRs (positive), PEG-AuNRs (neutral), PSS-AuNRs (negative)] were studied for the three most abundant proteins in the blood serum namely, human serum albumin, immunoglobulin tG, and transferrin. The variation in protein adsorption, mean hydrodynamic size, and zeta potential were studied for different protein incubation periods (0, 0.5, 1, 4, 8, 12, and 24 h). The soft and hard corona layers were estimated for the individual proteins and mixture of the three proteins at the time point of maximum protein adsorption (1 h). Finally, in order to study the biological consequence of the coronation of AuNRs, the cell viability and uptake of AuNRs before and after protein corona formation were studied. The formation of IgG corona helped to reduce cellular toxicity, and at the same time, showed improved cell uptake when compared to the respective as-prepared AuNRs, highlighting their application potential for drug delivery applications. © 2017 Elsevier B.V.

Impact of gold nanorod functionalization on biocorona formation and their biological implication

Gold nanorods (AuNRs) used for biomedical applications could be encountered by biomolecules in the bloodstream, of which IgG is the most abundant antibody. With a view to mitigate their side effect on encountered proteins, the effect of Au concentration (5–40 μM) and functionalization (CTAB-positive;PSS-negative; PEG-neutral) of AuNRs was investigated on the stability of a model protein, IgG (1 μM). Electron microscopic images and particle size analyses indicated least aggregation behavior for PEG-AuNRs, which can be correlated to their neutral charge (from zeta potential analyses) or stearic hindrance of PEG chains. Variations in tryptophan domain were probed by UV–visible absorption and fluorescence quenching studies. Synchronous fluorescence study helped to provide information regarding variations in the hydrophobic region of IgG. The denaturation studies also indicated the stability of AuNR–IgG complex formation. These studies showed that positively charged IgG (pI: 7.8 ± 1.0) was mostly affected by negatively charged PSS-AuNRs and least affected by PEG-AuNRs. This was verified by secondary structural investigations performed using CD and FTIR spectroscopy. For cytotoxicity studies on human lymphocytes, CTAB-AuNRs are known to show higher toxicity compared to PSS-AuNRs and PEG-AuNRs (least). Though PSS-functionalized AuNRs were shown to affect cells to a lesser degree based on the negative charge of cell membrane, they could hamper with positively charged biomolecules in the bloodstream before they reach the target, which must also be considered for choosing the right AuNR functionalization. Thus, this work indicates the effect of different AuNR functionalization on protein and cellular toxicity and stresses the necessity to use neutral particles to mitigate their side effect for theranostic applications. © 2016 Elsevier B.V.

Materials Science and Engineering: C

Significance of surface functionalization of Gold Nanorods for reduced effect on IgG stability and minimization of cytotoxicity

Therapeutic potential of the biosynthesised silver and platinum nanoparticles against lung carcinoma cell line. Cellular death was induced by oxidative stress followed by apoptosis.

RSC Advances

DNA damage and mitochondria-mediated apoptosis of A549 lung carcinoma cells induced by biosynthesised silver and platinum nanoparticles

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

Analytical Methods

Etching-based transformation of dumbbell-shaped gold nanorods facilitated by hexavalent chromium and their possible application as a plasmonic sensor

Since the nanoparticle usage in the biomedical field is increasing, it is necessary to understand their interaction with the biomolecules, such as proteins. The current study primarily investigates the interaction of BSA with the Al2O3 nanoparticles by various spectroscopic techniques. The experiments were carried out in three different experimental matrices, i.e. the distilled de-ionized water, the phosphate buffer and the saline media. The enhanced absorbance observed by UV-visible and fluorescence spectroscopy suggested the probable formation of a ground state complex of the type BSA-Al2O3. The apparent association constant (K app), calculated based on the spectral changes due to the association of BSA with Al2O3 NPs, was found to be higher in an aqueous system (pH 4.47) as compared to the other two matrices, suggesting the maximum interaction between BSA and Al2O3. The particle size analysis of Al2O3 in aqueous suspension demonstrated the possibility of BSA adsorption onto the NP surface. The FT-IR and the circular dichroism (CD) studies indicated that the Al2O3 NPs induced the structural changes in the BSA secondary structure, especially α-helix. © 2013 Elsevier B.V.

Journal	Data powered by TypesetJournal of Molecular Liquids
Publisher	Data powered by TypesetElsevier BV
ISSN	0167-7322
Open Access	0