Uma Maheswari Krishnan

SASTRA University, Tanjor, Tamil Nadu, India

Are you Uma Maheswari Krishnan?

Claim your profile

Publications (117)378.83 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A hybrid interface was developed using nano iron oxide and carbon nanotubes and this architecture offered an improved performance for the detection of hydrogen peroxide. Nano iron oxide was synthesized by a simple thermal co-precipitation technique and it was dispersed in nafionic solution. To this mixture added the catalase enzyme adsorbed multi-walled carbon nanotubes and this solution was used for the modification of the electrode. The morphology of the prepared nanocomposite was observed using FE-TEM and the electrochemical studies were carried out using cyclic voltammetry and amperometry. The linear range of the prepared amperometric sensor was found to be between 1.2 and 21.6 μM with a quick response time of less than 1 s. The interference, reproducibility and stability studies were carried out with satisfactory results. The limit of detection and limit of quantification were found to be 3.7 nM and 12.2 nM respectively. With the convincing results obtained in terms of the performance of the biosensor, this platform was successfully upgraded for the determination of hydrogen peroxide in the presence of milk samples.
    Sensors and Actuators B Chemical 08/2015; 215. DOI:10.1016/j.snb.2015.03.041 · 4.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Electrospun nanofibrous scaffolds have gained momentum in regenerative medicine research due to their ECM-like architecture. The present study reports the fabrication of mesoporous silica nanofibers (MSF) and explores its potential to trigger osteogenic differentiation of human bone marrow derived mesenchymal stem cells (BM-MSCs) in presence and absence of biochemical (induction) factors. BM-MSCs were seeded on MSF and allowed to differentiate into osteogenic lineage. Osteogenic differentiation of BM-MSCs was confirmed by mineralization staining, reduction in the expression of the stem cell marker CD105 and increase in the osteogenic marker osteocalcin. Cells cultured in MSF in presence of induction media exhibited better adhesion, proliferation and differentiation. The phenotypic markers of osteoblasts such as mineralization and alkaline phosphatase (ALP) activity were higher on MSF in presence of induction media when compared to MSF in presence of normal media (p<0.05). Upregulation of osteoblast specific genes (osteonectin, osteocalcin & alkaline phosphatase) suggest the potential of MSF to support osteogenic differentiation even in the absence of induction media (p<0.05). In vitro results indicate that the nanotopography of MSF provided a favorable milieu for adhesion and proliferation of BM-MSCs. Further, the combination of biomimetic nature of MSF, dissolution ions of silica (chemical cues) and biochemical cues presents a stable microenvironment for the differentiation of BM-MSCs into osteogenic lineage. In conclusion, the synergy of adhesion and proliferation cues in MSF along with a suitable biochemical cues could be a promising design strategy to develop scaffolds for orchestrated bone healing
    RSC Advances 08/2015; DOI:10.1039/C5RA07014G · 3.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Electrochemical biosensor for acetylcholine (ACh) estimation in human blood samples was developed, and various electrochemical parameters like charge consumed (Q, full width at half maximum (FWHM), electron transfer rate (K s), cathodic peak potential (E pc), surface coverage (Γ) and cathodic peak current (I pc) were investigated to study their interdependence by performing principal component analysis and hierarchical cluster analysis. Acetylcholinesterase (AChE) modified platinum (Pt) working electrode with ceria (CeO2) nanoparticles as an interface was used for electrochemical studies. Various regression models were analyzed in order to find the suitable model which can reduce the error and enhance the specificity of AChE modified Pt electrode towards ACh. The inter-parameter relationship study was utilized to improve the figure of merits of Pt/Nano-CeO2 at 773 K/AChE bioelectrode towards the quantification of ACh. The validation results implied that Q, and I pc have significant influence on the ACh concentration. And also, multiple linear regression model was efficient to predict the unknown concentration of ACh in human blood samples with high accuracy and specificity.
    Journal of Computational and Theoretical Nanoscience 08/2015; 12(8). DOI:10.1166/jctn.2015.3943 · 1.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Apart from nutritional value, fish food is considered as the high foreign exchange earners worldwide. Since fish food is highly perishable, histamine production in fish due to improper storage temperature causes allergic reactions like histamine toxicity (scromboid toxicity). Hence, accurate estimation of histamine in fish food has become a serious concern. In this context, to design a histamine biosensor with less error, high accuracy and specificity, the interdependent electrochemical parameters such as histamine concentration, cathodic peak current, electron transfer rate constant, amount of charge consumed, surface coverage and full width at half maximum of cathodic peak height were related to improve the efficiency of the GCE/CeO2-PANI/DAO modified electrode. The multivariate analysis such as principal component, hierarchical cluster analysis and multiple linear regression techniques were done with the estimated value of electrochemical parameters and it showed that the cathodic peak current, amount of charge consumed, surface coverage and full width at half maximum of cathodic peak height were highly related to the histamine concentration, whereas the electron transfer rate constant has no relationship with other electrochemical parameters. Finally, the combination of the Hill model with the multiple linear regression model effectively improved the specificity and accuracy of the histamine biosensor.
    Journal of Computational and Theoretical Nanoscience 08/2015; 12(8). DOI:10.1166/jctn.2015.3976 · 1.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Most of the metal ions are carcinogens and lead to serious health concerns by producing free radicals. Hence, fast and accurate detection of metal ions has become a critical issue. Among various metal ions arsenic, cadmium, lead, mercury and chromium are considered to be highly toxic. To detect these metal ions, electrochemical biosensors with interfaces such as microorganisms, enzymes, microspheres, nano-materials like gold, silver nanoparticles, CNTs, and metal oxides have been developed. Among these, nanomaterials are considered to be most promising, owing to their strong adsorption, fast electron transfer kinetics, and biocompatibility, which are very apt for biosensing applications. The coupling of electrochemical techniques with nanomaterials has enhanced the sensitivity, limit of detection, and robustness of the sensors. In this review, toxicity mechanisms of various metal ions and their relationship towards the induction of oxidative stress have been summarized. Also, electrochemical biosensors employed in the detection of metal ions with various interfaces have been highlighted.
    Sensors and Actuators B Chemical 07/2015; 213:515-533. DOI:10.1016/j.snb.2015.02.122 · 4.29 Impact Factor
  • Priyadharshini Kumaraswamy · Swaminathan Sethuraman · Uma Maheswari maheswari Krishnan
    [Show abstract] [Hide abstract]
    ABSTRACT: Alzheimer’s disease is a neurodegenerative disorder affecting millions of people worldwide clinically manifested by the presence of amyloid plaques and neurofibrillary tangles. Senile plaques are composed of amyloid beta protein while neurofibrillary tangles are formed by the hyperphosphorylation of tau protein. A plethora of reports on the anti-oxidant and pro-oxidant properties of amyloid beta peptide are available. However the molecular candidates involved bringing about this therapeutic behaviour is not explored. To investigate this phenomenon we have used a pentapeptide sequence KLVFF, derived from the core-recognition motif of amyloid beta peptide to study the altered signaling cascade in neuronal cells. Our data showed the unique dual behaviour of KLVFF peptide as pro-oxidant and toxicant based on the dosage concentration. The peptide’s inherent ability to scavenge free radicals at low concentrations <100 μM to offset oxidative stress was proved by the down-regulation of SOD1, AP-1 and FoxO3a genes. However at concentrations > 100 μM, the cytotoxic effect of the peptide dominates, leading to apoptosis through activation of p53, ERK1 and p38 in a caspase-dependent mechanism accompanied by mitochondrial membrane depolarization. The therapeutic role of KLVFF peptide stems out from the regulation of SOD1 gene by AP-1 and NF-κB and Nrf2 gene to regulate the intracellular glutathione levels. Collectively our experimental findings revealed a threshold concentration of 100 μM beyond which KLVFF peptide mimics the amyloid beta of senile plaque, which can be used as a model system to understand the pathological role of amyloid beta peptide. While concentrations below 100 μM may be actively employ for therapeutic applications to prevent the further aggregation of amyloid beta.
    RSC Advances 06/2015; 5(73). DOI:10.1039/C5RA10746F · 3.84 Impact Factor
  • Sathya Narayanan Vijayakumar · Swaminathan Sethuraman · Uma Maheswari maheswari Krishnan
    [Show abstract] [Hide abstract]
    ABSTRACT: Proliferation and self-sufficiency are two most important properties of cancer cells. Although genetic aberrations are believed to be the reason for cancer development, importance of metabolic alterations in cancer development have found the lime light lately. The most challenging aspect in cancer treatment has been their similarity to host cells. The discovery of various metabolic alterations that occur in cancers to attain and maintain proliferative state has resulted in new information on the metabolic differences between normal and cancer cells. One such alteration is the establishment of Warburg effect. This review elaborates on various changes that lead to establishment of Warburg effect in cancer cells and their consequences. Understanding the metabolic uniqueness of various cancers can aid in identification of novel molecular targets leading to more efficient strategies in cancer treatment.
    RSC Advances 04/2015; 5(52). DOI:10.1039/C5RA06505D · 3.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The presence of captan residues in apples shows high toxicity, which often causes eye and skin irritation, dermatitis, conjunctivitis, and vomiting in humans. In this context, an electrochemical biosensor based on acetylcholinesterase (AChE) immobilized on a ZnO nanorod interface has been proposed. In this work, Hill, dose-response, and first-, second-, and third-order polynomial regression models were successfully applied and the prediction ability of these models was tested with the use of current density obtained from the cyclic voltammograms of appropriate captan solutions. The Pt/ZnO/AChE bioelectrode showed a high sensitivity of 0.538 μA cm(-2) μM(-1) in the linear range from 0.05 to 25.0 μM with a limit of detection of 107 nM. The recovery results were observed between 98.4 and 102.4 % from the apple sample. This work provides a new promising tool for the detection of captan in apple samples.
    Analytical and Bioanalytical Chemistry 04/2015; 407(16). DOI:10.1007/s00216-015-8687-1 · 3.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this work, the electrochemical parameters, namely, amount of charge consumed, electron transfer rate constant, cathodic peak current, surface coverage, full width at half maximum of cathodic peak height and tributyrin concentration were interrelated to improve the figure of merits of the TCO/Nano-CeO2/lipase electrode towards the estimation of tributyrin in human serum samples. Principal component and hierarchical cluster analyses were performed with the estimated value of electrochemical parameters illustrated that the amount of charge consumed, cathodic peak current, surface coverage and full width at half maximum of cathodic peak height were significantly related with tributyrin concentration. And finally, a multiple linear regression model capable of reliably predicting tributyrin in human serum samples was developed.
    Journal of Computational and Theoretical Nanoscience 04/2015; 12(6). DOI:10.1166/jctn.2015.3832 · 1.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Linear sweep voltammetry was used as an analytical technique to measure methylglyoxal in blood samples by employing Pt/ZnO sepals/GLO 1 bio-electrode. In order to increase the specificity of glyoxalase towards methylglyoxal and to predict the non-linear relationship between added methylglyoxal concentrations and pairs of electrochemical parameters, non-linear logistic and gaussian cumulative response surface models were fitted to the experimental results using Levenberg-Marquardt algorithm. An excellent correlation (r = 0.99) was observed between the predicted and added methylglyoxal concentrations. The accuracy of the proposed models was validated by calculating relative prediction error (RPE), percentage recovery and root mean square error for cross validation (RMSECV). Only the MG = f(FWHM, Jpc) logistic cumulative response model showed best results in validation (RPE = 2.07 × 10–5, Recovery = 98.726% and RMSECV = –0.004). The calibrated non-linear model was further validated on human blood samples. The attained relative standard deviation and percentage recovery values calculated for spiked methylglyoxal concentrations (3 measurements) were typically below 6.54% and 116.48% respectively.
    Sensor Letters 04/2015; 13(4). DOI:10.1166/sl.2015.3439 · 0.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Theoretical investigation for the estimation of surface coverage based on Michaelis-Menten constant (K M) and detection limit was carried out. The influence of theoretical linear ranges on the surface concentration of adsorbed biomolecules was also investigated. The [S] < K M boundary-conditioned surface coverage model results are consistent with the theoretical calculations and give a precise determination of surface coverage.
    Sensor Letters 04/2015; 13(4). DOI:10.1166/sl.2015.3438 · 0.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Until now, various chemometric tools have been used to approximate solutions to address the nonlinear amperometric biosensor modeling challenge. Hence, an analytical method capable of predicting the non-constant slope (dynamic sensitivity) of a non-linear amperometric biosensor model has been developed. The dynamic sensitivity, and any given point in a given amperometric biosensor's operation, is predicted by solving a series of mathematical constants corresponding to the physical entities of the amperometric biosensor itself. In order to validate the proposed models, data of butyrin biosensor were considered. The effectiveness of these models was statistically analyzed and found that the first-order dynamic sensitivity model was better than that of the second order. This dynamic sensitivity slope prediction, in turn, can be used to predict the concentration of an analyte when a non-constant amperometric sensor response is known.
    Journal of Computational and Theoretical Nanoscience 04/2015; 12(6). DOI:10.1166/jctn.2015.3853 · 1.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A hybrid interface was developed using nano iron oxide and carbon nanotubes and this architecture offered an improved performance for the detection of hydrogen peroxide. Nano iron oxide was synthesized by a simple thermal co-precipitation technique and it was dispersed in nafionic solution. To this mixture added the catalase enzyme adsorbed multi-walled carbon nanotubes and this solution was used for the modification of the electrode. The morphology of the prepared nanocomposite was observed using FE-TEM and the electrochemical studies were carried out using cyclic voltammetry and amperometry. The linear range of the prepared amperometric sensor was found to be between 1.2 - 21.6 μM with a quick response time of less than 1 second. The interference, reproducibility and stability studies were carried out with satisfactory results. The limit of detection and limit of quantification was found to be 3.7 nM and 12.2 nM respectively. With the convincing results obtained in terms of the performance of the biosensor, this platform was successfully upgraded for the determination of hydrogen peroxide in the presence of milk samples.
    Sensors and Actuators B Chemical 03/2015; · 4.29 Impact Factor
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: Linear sweep voltammetric behaviour of methylglyoxal was investigated using Pt/ZnO flakes/GLO 1 bio-electrode and a new analytical method was developed for the precise and accurate determination of methylglyoxal in grilled chicken sample. This method was based on the electrochemical parameters measured for the increasing concentration of methylglyoxal. The electrochemical parameters calculated from the linear sweep voltammograms served as the dependent variables. The concentrations of methylglyoxal were employed as the independent variables. For each electrochemical parameter, a non-linear calibration equation was framed and its predictive performance was evaluated. The analytical performance of the proposed models was assessed with the aid of relative prediction error, % recovery and root mean square error for cross validation. The best results were obtained with current density versus [methylglyoxal] model (RPE = 0.033, Recovery = 97.379% and RMSECV = 1.429). This calibrated non-linear model was then applied for the determination of methylglyoxal in grilled chicken samples. The recovery of methylglyoxal in spiked grilled chicken was ranging from 95.895% to 108.191%. The predicted methylglyoxal values were very similar to that of the spiked methylglyoxal values.
    Sensor Letters 03/2015; 13(3). DOI:10.1166/sl.2015.3425 · 0.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Estimating lactate concentration in the meat food products has been a serious concern since it induces hepatic immaturity in children below the age of 3. This article is aimed to illustrate the statistical modeling for the estimation of lactate in meat food products and to identify the interrelation between the amount of lactate added to the phosphate buffered saline (0.1 M, 7.4 pH) and other electrochemical parameters such as amount of charge consumed, surface coverage, cathodic peak current, cathodic peak potential, full width at half maximum of cathodic peak height and electron transfer rate constant. The gold working electrode was modified by immobilizing lactate dehydrogenase on ZnO nanorods. The modified gold working electrode was used for the determination of lactate by linear sweep voltammetry. Multivariate data analysis was performed with the values of electrochemical parameters. This analysis showed the significant relation between the amount of charge consumed and full width at half maximum of cathodic peak height with the added lactate concentrations. Based on these relationships, a multiple linear regression model was framed for the estimation of lactate in meat food products.
    Journal of Computational and Theoretical Nanoscience 03/2015; 12(3). DOI:10.1166/jctn.2015.3744 · 1.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Nano delivery systems have significantly evolved over the last decade for the treatment of cancer by enabling site-specific delivery and improved bioavailability. The widely investigated nanoparticle systems are biodegradable polyesters, dendrimers, liposomes, mesoporous silica and gold nanoparticles. These particles when conjugated with different targeting motifs enhance the therapeutic efficiency of the drug molecules and biocompatibility. However, the application of such systems towards the treatment of retinoblastoma (RB), a rapidly spreading childhood eye cancer, still remains in its infancy. Nanoparticle-based systems that have been investigated for RB therapy have displayed improved drug delivery to the most restricted posterior segment of the eyes and have increased intra-vitreal half-life of the chemotherapy agents highlighting its potential in treatment of this form of cancer. This review focuses on the challenges involved in the treatment of RB and highlights the attempts made to develop nano-dimensional systems for the treatment of RB.
    Drug Delivery 02/2015; DOI:10.3109/10717544.2015.1016193 · 2.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: A major limitation in gene delivery applications employing nanocarriers is the inflammatory response elicited when administered in vivo. The mode of complexation of the oligonucleotide with the carrier can alter its interactions with biomolecules, a fact that has not been explored for lipoplexes hitherto. Materials: Liposomes prepared by thin film hydration were used to form lipoplexes of si-RNA and DNA, which exhibited a smaller size and a shift towards negative zeta potential when compared with blank liposomes. Results: The oligonucleotides wrap over the liposome surface and the surface coverage depends on the number of base pairs. The colloidal stability, protein resistance and cell uptake of lipoplexes were found to be dependent on surface charge and PEG. The lipoplexes with si-RNA did not induce cytokine production in BALB/c mice. Conclusion: The results highlight the importance of PEGylation for achieving good protein resistance without compromising cell uptake and therapeutic efficiency.
    Nano brief reports and reviews 01/2015; 10(04). DOI:10.1142/S1793292015500526 · 1.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Regeneration of functional small diameter blood vessels still remains a challenge, as the synthetic vascular grafts fail to mimic the complex structural architecture and dynamic functions of blood vessels and also lack with the lack of non-thrombogenicity. Although, the existence of nanofibrous extracellular matrix components in the native tissue promotes many physical and molecular signals to the endothelial cells for the regulation of morphogenesis, homeostasis, and cellular functions in vascular tissue, poor understanding of the structural architecture on the functional activation of appropriate genes limits the development of successful vascular graft design. Hence, the present review outlines the functional contributions of various nanofibrous extracellular matrix components in native blood vessels. Further, the review focuses on the role of nanofiber topography of biomaterial scaffolds in endothelial cell fate processes such as adhesion, proliferation, migration, and infiltration with the expression of vasculature specific genes; thereby allowing the reader to envisage the communication between the nano-architecture of scaffolds and endothelial cells in engineering small diameter vascular grafts.
    Biotechnology Journal 01/2015; 10(1). DOI:10.1002/biot.201400415 · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Three-dimensional liver scaffolds are temporary framework that mimics native ECM architecture and positively influence hepatocyte lodging, proliferation with retention of metabolic activities. The aim of the current study is to develop galactose containing physical cross-linked polyvinyl alcohol/gelatin (P/G 8:2 and 9:1) hydrogel scaffolds via freeze/thaw technique. The 8:2 and 9:1 P/G hydrogels exhibited comparable pore size and porosity (P > 0.05). The tensile strength of the fabricated 8:2 and 9:1 P/G hydrogel scaffolds were found to be in accordance with native human liver. Pore interconnectivity of both the P/G hydrogel scaffolds was confirmed by scanning electron micrographs and liquid displacement method. Further galactose containing hydrogel promoted cell-cell and cell-hydrogel interaction, aiding cellular aggregation leading to spheroids formation compared to void P/G hydrogel by 7 days. Hence, galactose containing P/G hydrogel could be more promising substrate as it showed significantly higher cell proliferation and albumin secretion for 21 days when compared to non-galactose P/G hydrogels (P < 0.05).
    Journal of Materials Science Materials in Medicine 01/2015; 26(1):5345. DOI:10.1007/s10856-014-5345-7 · 2.38 Impact Factor