Aditya Kurdekar

Aqueous based reflux method for green synthesis of nanostructures: Application in CZTS synthesis

Graphical abstract

Femtogram Level Sensitivity achieved by Surface Engineered Silica Nanoparticles in the Early Detection of HIV Infection

We have engineered streptavidin labelled Europium doped fluorescent silica nanoparticles which significantly increased sensitivity without compromising the specificity of the immunoassay. As a proof of concept, a time resolved fluorescence based sandwich immunoassay was developed to detect HIV-1 p24 antigen in clinical specimens. The detection range of the silica nanoparticle based immunoassay (SNIA) was found to be between 0.02 to 500 pg/mL in a linear dose dependent manner. SNIA offers 1000 fold enhancement over conventional colorimetric ELISA. Testing of plasma samples that were HIV negative showed no false positive results in the detection of HIV-1 p24 antigen. This highly sensitive p24 assay can help improve blood safety by reducing the antibody negative window period in blood donors in resource limited settings where nucleic acid testing is not practical or feasible. This technology can also be easily transferred to a lab-on-a-chip platform for use in resource limited settings and can also be easily adopted for the detection of other antigens.

Fluorescent silver nanoparticle based highly sensitive immunoassay for early detection of HIV infection

For the first time, we have engineered streptavidin labeled fluorescent silver nanoparticles for their application in immunosensing of biomolecules which will significantly increase sensitivity without compromising the specificity. A computational perspective for understanding the efficiency of the conjugation process is provided as a proof of concept. The fluorescence based sandwich immunoassay was demonstrated to detect HIV-1 p24 antigen in clinical specimens with improved sensitivity and specificity. The detection range of the fluorescent silver nanoparticle-based immunoassay (FSNIA) was found to be between 10 and 1000 pg mL−1 in a linear dose dependent manner. False positives were not observed with plasma samples from healthy adults (HIV−ve), hepatitis B (HBV+ve) and hepatitis C (HCV+ve). Plasma samples that were HIV−ve showed no interference with detection of HIV-1 p24 antigen. This technology can be used in resource limited settings and easily adopted for the detection of other pathogen antigens.

Application of nanotechnology in biosensors for enhancing pathogen detection

Rapid detection and identification of pathogenic microorganisms is fundamental to minimizing the spread of infectious disease, and informing clinicians on patient treatment strategies. This need has led to the development of enhanced biosensors that utilize state of the art nanomaterials and nanotechnology, and represent the next generation of diagnostics. A primer on nanoscale biorecognition elements such as, nucleic acids, antibodies, and their synthetic analogs (molecular imprinted polymers), will be presented first. Next the application of various nanotechnologies for biosensor transduction will be discussed, along with the inherent nanoscale phenomenon that leads to their improved performance and capabilities in biosensor systems. A future outlook on characterization and quality assurance, nanotoxicity, and nanomaterial integration into lab-on-a-chip systems will provide the closing thoughts. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > Biosensing.

Surface plasmon coupled emission as a novel analytical platform for the sensitive detection of cysteine

Abstract Thiolated amino acids are biologically important molecules due to their role in protein folding and structure. One such molecule is cysteine (Cys), which acts as a biomarker for diseases like cancer, HIV, sepsis, etc., making its rapid detection imperative and essential. In this study, we report the sensitive detection of the thiolated amino acid Cys, from the non-thiolated amino acid arginine (Arg), using the novel surface plasmon coupled emission (SPCE) platform, characterized with high signal-to-noise ratios. Our studies were performed on the conventional silver (Ag) SPCE substrate, where Cys was detected to a nanomolar level, which is a major improvement to the previously reported level of sensitivity. This can be attributed to the highly sensitive SPCE platform and the unique thiol-Ag interactions associated specifically with Cys. We have also shown the role and influence of the coating process on sensitivity of detection and substantiated the advantages of SPCE over the SPR-based strategy of detection. The simplistic and economical SPCE platform enabled the sensitive detection of Cys that is of biological and medical relevance.