Mohankandhasamy Ramasamy | Yeungnam University (original) (raw)

Papers by Mohankandhasamy Ramasamy

A rapid, sensitive and selective HPLC method was developed for the determination of pantoprazole ... more A rapid, sensitive and selective HPLC method was developed for the determination of pantoprazole in rat plasma. In this method, pantoprazole was extracted from rat plasma using acetonitrile with Lansoprazole as internal standard. Analysis was achieved on a Phenomenex C 18 column with water (pH 7.0)-acetonitrile (55:45%, v/v) as the mobile phase. Enteric coated pantoprazole tablets from Pantocid (test, Sun pharmaceuticals, India) and from Pantop (reference, Aristo pharmaceuticals, India) were evaluated following 20mg oral dose to healthy rats. The pharmacokinetic parameters C max, AUC 0-t , AUC 0-∞ , T max and t 1/2 were determined from plasma concentration-time profile of both formulations and found to be in good agreement with previously reported values. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two formulations. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range. Based on these statistical inferences it was concluded that the two formulations exhibited comparable pharmacokinetic profiles and that Pantocid is bioequivalent to Pantop.

ACS applied materials & interfaces, Jan 10, 2014

Well-packed two- and three-dimensional (2D and 3D) gold nanorod (AuNR) arrays were fabricated usi... more Well-packed two- and three-dimensional (2D and 3D) gold nanorod (AuNR) arrays were fabricated using confined convective arraying techniques. The array density could be controlled by changing the concentration of the gold nanorods solution, the velocity of the moving substrate, and the environment air-temperature. The hydrophilic behavior of glass substrates before and after surface modification was studied through contact angle measurements. The affinity and alignment of the AuNR arrays with varying nanorod concentrations and the resulting different array densities were studied using field emission scanning electron microscopy (FE-SEM). Under stable laser intensity irradiation, the photothermal response of the prepared arrays was measured using a thermocouple and the results were analyzed quantitatively. Synthesized AuNR arrays were added to Escherichia coli (E. coli) suspensions and evaluated for photothermal bactericidal activity before and after laser irradiation. The results sho...

We describe the nucleophilic hybridization technique for fabricating magnetic nanoparticle (MNP) ... more We describe the nucleophilic hybridization technique for fabricating magnetic nanoparticle (MNP) around gold nanorod (AuNR) for desired photo-thermal lysis on pathogenic bacteria. From the electromagnetic energy conversion into heat to the surrounding medium, a significant and quicker temperature rise was noted after light absorption on nanohybrids, at a controlled laser light output and optimum nanoparticle concentration. We observed a similar photo-thermal pattern for more than three times for the same material up on repeated magnetic separation. Regardless of the cell wall nature, superior pathogenic cell lysis has been observed for the bacteria suspensions of individual and mixed samples of Salmonella typhi (S.typhi) and Bacillus subtilis (B.subtilis) by the photo-heated nanoparticles. The synthesis of short gold nanorod, conjugation with magnetic nanoparticle and its subsequent laser exposure provides a rapid and reiterated photo-thermal effect with enhanced magnetic separation for efficient bactericidal application in water samples. Resultant novel properties of the nano-aggregates makes them a candidate to be used for a rapid, effective, and reiterated photo-thermal agent against a wide variety of pathogens to attain microbe free water.

The objective of this study was to develop a bimetallic nanoparticle with enhanced antibacterial ... more The objective of this study was to develop a bimetallic nanoparticle with enhanced antibacterial activity that would improve the therapeutic efficacy against bacterial biofilms. Bimetallic gold–silver nanoparticles were bacteriogenically synthesized using-proteobacterium, Shewanella oneidensis MR-1. The antibacterial activities of gold–silver nanoparticles were assessed on the planktonic and biofilm phases of individual and mixed multi-cultures of pathogenic Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive bacteria (Enterococcus faecalis and Staphylococcus aureus), respectively. The minimum inhibitory concentration of gold–silver nanoparticles was 30–50 mM than that of other nanoparticles (>100 mM) for the tested bacteria. Interestingly, gold–silver nanoparticles were more effective in inhibiting bacterial biofilm formation at 10 mM concentration. Both scanning and transmission electron microscopy results further accounted the impact of gold–silver nanoparticles on biocompatibility and bactericidal effect that the small size and bio-organic materials covering on gold–silver nanoparticles improves the internalization and thus caused bacterial inacti-vation. Thus, bacteriogenically synthesized gold–silver nanoparticles appear to be a promising nanoantibiotic for overcoming the bacterial resistance in the established bacterial biofilms.

Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an... more Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces.

International Journal of Nanomedicine, 2015

Letters in Applied Microbiology, 2015

Virulence inhibition by quorum quenchers in Pseudomonas aeruginosa is usually tested in laborator... more Virulence inhibition by quorum quenchers in Pseudomonas aeruginosa is usually tested in laboratory strains and studies of their effects in relevant clinical and environmental strains are scarce. This study is significant since the effects of ZnO nanoparticles in QS-dependent virulence factor production were tested in 6 clinical strains from cystic fibrosis patients, a C-30 resistant clinical strain from urine, two PA14 gallium resistant mutants, a PA14 C-30 resistant mutant and 4 environmental isolates. ZnO nanoparticles decreased elastase, pyocyanin, and biofilms for most of the strains; indicating they have broad spectrum and may be an alternative to treat P. aeruginosa infections.

A rapid, sensitive and selective HPLC method was developed for the determination of pantoprazole... more A rapid, sensitive and selective HPLC method was developed for the determination of pantoprazole
in rat plasma. In this method, pantoprazole was extracted from rat plasma using acetonitrile with Lansoprazole as
internal standard. Analysis was achieved on a Phenomenex C
18
column with water (pH 7.0)-acetonitrile (55:45%,
v/v) as the mobile phase. Enteric coated pantoprazole tablets from Pantocid (test, Sun pharmaceuticals, India) and
from Pantop (reference, Aristo pharmaceuticals, India) were evaluated following 20mg oral dose to healthy rats.
The pharmacokinetic parameters C
max,
AUC
0-t
, AUC
0-
∞
, T
max
and t
1/2
were determined from plasma concentration-
time profile of both formulations and found to be in good agreement with previously reported values. The
calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two
formulations. The analysis of variance (ANOVA) did not show any significant difference between the two
formulations and 90% confidence intervals fell within the acceptable range. Based on these statistical inferences it
was concluded that the two formulations exhibited comparable pharmacokinetic profiles and that Pantocid is
bioequivalent to Pantop

Hepatitis B virus surface antigen (HBsAg) loaded N,N,N-trimethyl chitosan nanoparticles (N-TMC NP... more Hepatitis B virus surface antigen (HBsAg) loaded N,N,N-trimethyl chitosan nanoparticles (N-TMC NPs) were formulated and studied for controlled intranasal delivery. The size and surface properties of the NPs can be tuned by modifying the concentration of N-TMC and found to be 66 ± 13, 76 ± 9 nm for 0.25 and 0.5 wt.% respectively. Loading of 380 and 760 μl of HBsAg yielded 143 ± 33, 259 ± 47 nm sized spherical N-TMC NPs with highest loading efficiency and capacity of 90–93%, and 96–97% respectively. In vitro drug release analysis ensured 93% cumulative release of HBsAg antigen over prolonged period (43 days). In vivo immunological study was performed using 6–8 weeks old female BALB mice and reveals adjuvants efficiency of NPs for antigen is highly stable and better than standard. Obtained results show that N-TMC NPs can be extensively used in controlled intra nasal delivery to treat various diseases including hepatitis B and allergic rhinitis.

The wide-scale applications of zinc oxide (ZnO) nanoparticles (NPs) in photocatalysts, gas sensor... more The wide-scale applications of zinc oxide (ZnO) nanoparticles (NPs) in photocatalysts, gas sensors, and cosmetics may cause toxicity to humans and environments. Therefore, the aim of the present study was to reduce the toxicity of ZnO NPs by coating them with a silica (SiO2) layer, which could be used in human applications, such as cosmetic preparations. The sol–gel method was used to synthesize core ZnO with SiO2-shelled NPs (SiO2/ZnO NPs) with varying degrees of coating. Diverse studies were performed to analyze the toxicity of NPs against cells in a dose- and time-dependent manner. To ensure the decreased toxicity of the produced SiO2/ZnO NPs, cytotoxicity in membrane damage and/or intracellular reactive oxygen species (ROS) were assessed by employing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, lactate dehydrogenase, 2′,7′-dichlorofluorescin, and lipid peroxide estimations. The cores of ZnO NPs exhibited cytotoxicity over time, regardless of shell thickness. Nevertheless, the thicker SiO2/ZnO NPs revealed reduced enzyme leakage, decreased peroxide production, and less oxidative stress than their bare ZnO NPs or thinner SiO2/ZnO NPs. Therefore, thicker SiO2/ZnO NPs moderated the toxicity of ZnO NPs by restricting free radical formation and the release of zinc ions, and decreasing surface contact with cells.

Novel, recyclable anti-bacterial Janus particles (AuNRs–PS–MNPs) were produced successfully by co... more Novel, recyclable anti-bacterial Janus particles (AuNRs–PS–MNPs) were produced successfully by combination of a confined convective assembly method and modified layer-by-layer technology. The Janus particles, one hemisphere of polystyrene coated by gold nanorods (AuNRs) and the other was coated by magnetic nanoparticles (MNPs), have both the properties of AuNRs and MNPs, therefore AuNRs–PS–MNPs could be collected by a magnet and produce heat under NIR irradiation. The survival rate of Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) treated with AuNRs–PS–MNPs and NIR were investigated using live/dead staining techniques, which confirmed the novel Janus particles worked as an efficient antibacterial agent.

Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully an... more Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully and melt blended with poly(ethylene-co-acrylic acid) (PEAA resin) to improving ultraviolet (UV) shielding of zinc oxide nanoparticles (ZnO NPs). The photostability of both the ZnO NPs and Si-ZnO NPs were analyzed by the difference in photoluminescence (PL) and by methylene blue (MB) degradation. Photo-degradation studies confirmed that Si-ZnO NPs are highly photostable compared to ZnO NPs. The melt blended matrices were characterized by field emission scanning electron microscopy interfaced with energy dispersive X-ray spectroscopy (FE-SEM-EDX). The UV shielding property was analyzed from the transmittance spectra of UV–visible (UV–vis) spectroscopy. The results confirmed fine dispersion of thick Si-ZnO NPs in the entire resin matrix. Moreover, the Si-ZnO/PEAA showed about 97% UV shielding properties than the ZnO/PEAA.

A new antibacterial gold nanorod (GNR) conjugated magnetic nanoparticle (MNP) composite (GNR–MNP)... more A new antibacterial gold nanorod (GNR) conjugated magnetic nanoparticle (MNP)
composite (GNR–MNP) was synthesized successfully for the eradication of antibiotic
resistant nosocomial pathogens in water to improve the water quality. The composite was
fabricated via the reaction of nucleophilic amine and epoxid

ACS applied materials & interfaces, Jan 10, 2014

International Journal of Nanomedicine, 2015

Letters in Applied Microbiology, 2015

A rapid, sensitive and selective HPLC method was developed for the determination of pantoprazole... more A rapid, sensitive and selective HPLC method was developed for the determination of pantoprazole
in rat plasma. In this method, pantoprazole was extracted from rat plasma using acetonitrile with Lansoprazole as
internal standard. Analysis was achieved on a Phenomenex C
18
column with water (pH 7.0)-acetonitrile (55:45%,
v/v) as the mobile phase. Enteric coated pantoprazole tablets from Pantocid (test, Sun pharmaceuticals, India) and
from Pantop (reference, Aristo pharmaceuticals, India) were evaluated following 20mg oral dose to healthy rats.
The pharmacokinetic parameters C
max,
AUC
0-t
, AUC
0-
∞
, T
max
and t
1/2
were determined from plasma concentration-
time profile of both formulations and found to be in good agreement with previously reported values. The
calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two
formulations. The analysis of variance (ANOVA) did not show any significant difference between the two
formulations and 90% confidence intervals fell within the acceptable range. Based on these statistical inferences it
was concluded that the two formulations exhibited comparable pharmacokinetic profiles and that Pantocid is
bioequivalent to Pantop