Satish Balasaheb Nimse

Free radicals, natural antioxidants, and their reaction mechanisms

The normal biochemical reactions in our body, increased exposure to the environment, and higher levels of dietary xenobiotics result in the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). The ROS and RNS create oxidative stress in different pathophysiological conditions. The reported chemical evidence suggests that dietary antioxidants help in disease prevention. The antioxidant compounds react in one-electron reactions with free radicals in vivo/in vitro and prevent oxidative damage. Therefore, it is very important to understand the reaction mechanism of antioxidants with the free radicals. This review elaborates the mechanism of action of the natural antioxidant compounds and assays for the evaluation of their antioxidant activities. The reaction mechanisms of the antioxidant assays are briefly discussed (165 references). Practical applications: understanding the reaction mechanisms can help in evaluating the antioxidant activity of various antioxidant compounds as well as in the development of novel antioxidants.

Immobilization techniques for microarray: challenges and applications.

The highly programmable positioning of molecules (biomolecules, nanoparticles, nanobeads, nanocomposites materials) on surfaces has potential applications in the fields of biosensors, biomolecular electronics, and nanodevices. However, the conventional techniques including self-assembled monolayers fail to position the molecules on the nanometer scale to produce highly organized monolayers on the surface. The present article elaborates different techniques for the immobilization of the biomolecules on the surface to produce microarrays and their diagnostic applications. The advantages and the drawbacks of various methods are compared. This article also sheds light on the applications of the different technologies for the detection and discrimination of viral/bacterial genotypes and the detection of the biomarkers. A brief survey with 115 references covering the last 10 years on the biological applications of microarrays in various fields is also provided.

9G DNAChip: microarray based on the multiple interactions of 9 consecutive guanines

We introduce the phenomenon of molecular recognition to immobilize oligonucleotides on AMCA slides for the production of 9G DNAChips. Facile and efficient method for the immobilization of the oligonucleotides appended with consecutive nine guanine bases is described. The 9G DNAChips shows more than 90% hybridization efficiency at 25 °C in 30 min.

HPV 9G DNA Chip: 100% Clinical Sensitivity and Specificity

ABSTRACT We describe a novel HPV 9G DNA chip test for the accurate and reliable genotyping of human papillomavirus (HPV). The HPV 9G DNA chip test established its efficiency in terms of a signal-to-background ratio (SBR) of 200, which is 50 times superior to commercial HPV DNA chips, and 100% target-specific hybridization at 25°C. We compared the genotyping results for the 439 clinical samples by the HPV 9G DNA chip test with the sequencing results for the MY11/GP6+ (M2) primer set-mediated PCR products. The discrimination of HPV genotypes in the 151 HPV-positive clinical samples by the HPV 9G DNA chip test were 100% identical with the sequencing analysis. The clinical sensitivities of HPV genotyping by the HPV 9G DNA chip test and a commercial HPV DNA chip test were 100% and 88%, respectively. However, the clinical specificities of HPV genotyping by the HPV 9G DNA chip test and the commercial HPV DNA chip test were 100% and 94%, respectively. The 100% clinical sensitivity and specificity of the HPV 9G DNA chip test make it a promising diagnostic tool for HPV genotyping.

HPV 9G DNAChip: Based on the 9G DNAChip technology.

The novel HPV 9G DNAChips were developed for the detection and discrimination of the HPV genotypes in the clinical samples. The HPV 9G DNAChip established high SBR of 50-70 and 100% target-specific hybridization after 30min hybridization and 2×2min washing at 25°C. We compared the genotyping results of the 959 HPV positive and 82 HPV negative clinical samples by the HPV 9G DNAChip and the sequencing; the results are in 100% agreement. The HPV 9G DNAChip efficiently discriminate 19 HPV genotypes in the 959 HPV positive clinical samples. The results of HPV 9G DNAChip were 100% identical with the sequencing analysis in the detection and discrimination of HPV genotypes in the HPV negative clinical samples. The high SBR, 100% target-specific hybridization, and 25°C hybridization and washing makes the HPV 9G DNAChip a promising diagnostic tool for the accurate HPV genotyping.

Surface Modification Chemistries of Materials Used in Diagnostic Platforms with Biomolecules

Biomolecules including DNA, protein, and enzymes are of prime importance in biomedical field. There are several reports on the technologies for the detection of these biomolecules on various diagnostic platforms. It is important to note that the performance of the biosensor is highly dependent on the substrate material used and its meticulous modification for particular applications. Therefore, it is critical to understand the principles of a biosensor to identify the correct substrate material and its surface modification chemistry. The imperative surface modification for the attachment of biomolecules without losing their bioactivity is a key to sensitive detection. Therefore, finding of a modification method which gives minimum damage to the surface as well as biomolecule is highly inevitable. Different surface modification technologies are invented according to the type of a substrate used. Surface modification techniques of the materials used as platforms in the fabrication of biosensors are reviewed in this paper.

9G DNAChip Technology: Self-Assembled Monolayer (SAM) of ssDNA for Ultra-Sensitive Detection of Biomarkers

A 9G DNAChip obtained by allowing the formation of a self-assembled monolayer (SAM) of oligonucleotides appended with nine consecutive guanines on the chip surface has been applied in the detection of biomarkers. Using a 9G DNAChip, biomarker in the concentration range of 4 pg/mL to 40 fg/mL can be easily differentiated in the buffer matrix. Moreover, it is the first time that a biomarker with a concentration of 40 fg/mL has been detected in a mixture of proteins without use of any signal amplification technique.

6 HCV genotyping 9G test and its comparison with VERSANT HCV genotype 2.0 assay (LiPA) for the hepatitis C virus genotyping

In this article, we describe the 6 HCV Genotyping 9G test and its evaluation by using clinical samples and plasmid DNA standards. In tests with 981 plasmid DNA standards, the 6 HCV Genotyping 9G test showed higher than 92.5% sensitivity and 99.4% specificity. The 6 HCV Genotyping 9G test was compared with the VERSANT HCV Genotype 2.0 assay (LiPA 2.0) for detection and discrimination of HCV genotypes in clinical samples. The results of both tests were verified by genomic sequencing. The 6 HCV Genotyping 9G test demonstrated a 100% agreement with the sequencing results, which was higher than LiPA 2.0. These results indicate that the 6 HCV Genotyping 9G test can be a reliable, sensitive, and accurate diagnostic tool for the correct identification of HCV genotypes in clinical specimens. 6 HCV Genotyping 9G test can genotype six HCV types in 1 PCR in 30min after PCR amplification. The 6 HCV Genotyping 9G test, thus provide critical information to physicians and assist them to apply accurate drug regimen for the effective hepatitis C treatment.In this article, we describe the 6 HCV Genotyping 9G test and its evaluation by using clinical samples and plasmid DNA standards. In tests with 981 plasmid DNA standards, the 6 HCV Genotyping 9G test showed higher than 92.5% sensitivity and 99.4% specificity. The 6 HCV Genotyping 9G test was compared with the VERSANT HCV Genotype 2.0 assay (LiPA 2.0) for detection and discrimination of HCV genotypes in clinical samples. The results of both tests were verified by genomic sequencing. The 6 HCV Genotyping 9G test demonstrated a 100% agreement with the sequencing results, which was higher than LiPA 2.0. These results indicate that the 6 HCV Genotyping 9G test can be a reliable, sensitive, and accurate diagnostic tool for the correct identification of HCV genotypes in clinical specimens. 6 HCV Genotyping 9G test can genotype six HCV types in 1 PCR in 30min after PCR amplification. The 6 HCV Genotyping 9G test, thus provide critical information to physicians and assist them to apply accurate drug regimen for the effective hepatitis C treatment.

Detection, quantification, and profiling of PSA: current microarray technologies and future directions

Prostate cancer (PCa) is a cancer of the prostate gland. The death rate of 13% among the men diagnosed with PCa makes it the second leading cause of cancer death. It has been reported that the monitoring of the progression of PCa and response to therapy is done by measuring the level of blood PSA. Even though PSA has been used for the diagnosis of PCa, the current scenario dictates the necessity of simultaneous detection of more than one biomarker. This critical review evaluates the DNA microarray and protein microarray based methods reported in the last five years for the detection, quantification, and profiling of PSA.

HPV genotyping 9G membrane test: a point-of-care diagnostic platform.

The results of HPV detection in 550 cervical samples by cervical cytology were compared with the sequencing analysis and HPV genotyping 9G membrane test. The HPV genotyping 9G membrane test can efficiently identify and discriminate five HR-HPV genotypes. The 100% identical results of HPV genotyping 9G membrane tests with the sequencing results in 550 clinical samples ensure its wide clinical applicability. The simple handling steps and the portable scanning device make the HPV genotyping 9G membrane test applicable in point-of-care settings. Moreover, the HPV genotyping 9G membrane test allows one to obtain final results in 30 min at 25 °C by simply loading the hybridization and washing solution and scanning the membranes without any drying steps or special handling. The clinical sensitivity and specificity of the HPV genotyping 9G membrane test was found to be 100%, which is much higher than cervical cytology.