Mukesh Digambar Sonawane

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.

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.

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.

6 HCV Genotyping 9G test for HCV 1a, 1b, 2, 3, 4 and 6 (6a, 6f, 6i and 6n) with high accuracy

According to EASL guidelines and WHO recommendations, the accurate detection of HCV genotypes such as HCV 1a, HCV1b, HCV 2, HCV 3, HCV 4, and HCV 6 (6a, 6f, 6i, 6n) is crucial for the efficient treatment of hepatitis C. HCV Genotyping 9G test allows simultaneous genotyping of HCV 1a, 1b, 2, 3, 4, and 6 (6a, 6f, 6i, and 6n) in clinical samples in 30min. The performance of the test was evaluated by comparison with sequence analysis. Serum samples (n=152) from HCV-infected patients (n=110) and healthy individuals (n=42) were processed under blinded codes. The k coefficient (kappa) values indicated high agreement between the HCV Genotyping 9G test and sequencing. The sensitivity and specificity of the test were 99.1% and 99.7%, respectively. The results indicate that HCV Genotyping 9G test is rapid, reliable, sensitive, and accurate for screening and genotyping of HCV in the clinical specimens.

Multiplex detection of cardiac biomarkers

A method for multiplex detection of three cardiac markers cTnI, NT-proBNP, and cTnT specific to CVD is reported. The low SBR and high specificity of the detection allowed us to achieve a detection limit of 6.8 pg mL−1. The proposed method allows the multiplex detection of cardiac biomarkers with LODs of 25.3 pg mL−1 (cTnI), 6.8 pg mL−1 (NT-proBNP), and 9.7 pg mL−1 (cTnT).

C-Reactive protein: a major inflammatory biomarker

Inflammatory biomarkers are released during tumour growth, and they are highly associated with stages of cancer progression. C-Reactive protein is one of the widely studied marker proteins, which is associated with inflammation. CRP levels have been used to predict survival in patients with different cancers. The assimilation of CRP into prognostic models for cancers improves their predictive accuracy. The analysis of changes in CRP concentration over time can allow for the prediction of tumour aggressiveness and treatment efficacy. Therefore CRP can be an important biomarker for cancer diagnosis and prognosis, and the monitoring of treatment outcomes. This critical review focuses on the role of C-reactive protein in different types of cancers and its relation to the different stages of cancer. This article also focuses on recently reported methods for the detection of CRP.

HBV/4DR 9G test and its comparison with INNO-LiPA HBV multi-DR test for the detection of drug-resistant Hepatitis B virus.

A significant proportion of patients with chronic Hepatitis B infection require antiviral therapy during their life time. The Antiviral therapy with lamivudine or adefovir or telbivudine has shown to be a major risk factor for selection of resistance. Eighty percent of patients showed a development of lamivudine-resistant strains after five years of treatment with lamivudine alone. Adefovir and telbivudine inhibit HBV with very high efficacy and have moderate incidences of drug resistance. Entecavir and tenofovir have been shown to have a higher barrier to resistance with rates of less than 1.5% after five years of treatment. The rtA181V, rtM204V/I, rtN236T and, rtM250V are high prevalent mutations found in the drug-resistant HBV strains. Therefore, for accurate treatment of HBV-infected patients, it is important to discriminate the drug-resistant HBV strains by using simple and accurate detection method. In this study, we describe the HBV/4DR 9G test and its evaluation by using clinical samples and plasmid DNA standards with a range of HBV mutation sites. In tests with 384 plasmid DNA standards, the HBV/4DR 9G test showed higher than 95% sensitivity and 98% specificity. The HBV/4DR 9G test was compared with the INNO-LiPA HBV Multi DR test for detection of drug-resistant HBV strains only in clinical samples. The plasma samples were collected from patients suspected with HBV drug-resistant strain infection. The results of both tests were cross-checked with the HBV DNA sequence analysis. The HBV/4DR 9G test demonstrated a good agreement with the sequencing results as compared to the INNO-LiPA HBV Multi-DR test. These results indicate that the HBV/4DR 9G test can be a reliable, sensitive, and accurate diagnostic tool for the detection of drug-resistant genotypes of HBV in clinical specimens. HBV/4DR 9G test can genotype 4 drug resistant HBV strains in 1 PCR. The HBV/4DR 9G test will help to minimize the risk of HBV patients from liver cancer.

Ultra-Sensitive NT-proBNP Quantification for Early Detection of Risk Factors Leading to Heart Failure

Cardiovascular diseases such as acute myocardial infarction and heart failure accounted for the death of 17.5 million people (31% of all global deaths) in 2015. Monitoring the level of circulating N-terminal proBNP (NT-proBNP) is crucial for the detection of people at risk of heart failure. In this article, we describe a novel ultra-sensitive NT-proBNP test (us-NT-proBNP) that allows the quantification of circulating NT-proBNP in 30 min at 25 °C in the linear detection range of 7.0–600 pg/mL. It is a first report on the application of a fluorescence bead labeled detection antibody, DNA-guided detection method, and glass fiber membrane platform for the quantification of NT-proBNP in clinical samples. Limit of blank, limit of detection, and limit of quantification were 2.0 pg/mL, 3.7 pg/mL, and 7 pg/mL, respectively. The coefficient of variation was found to be less than 10% in the entire detection range of 7–600 pg/mL. The test demonstrated specificity for NT-proBNP without interferences from bilirubin, intra-lipid, biotin, and hemoglobin. The serial dilution test for plasma samples containing various NT-proBNP levels showed the linear decrement in concentration with the regression coefficient of 0.980–0.998. These results indicate that us-NT-proBNP test does not suffer from the interference of the plasma components for the measurement of NT-proBNP in clinical samples.