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Geetha Balakrishna R

Bio: Geetha Balakrishna R is an academic researcher from Jain University. The author has an hindex of 1, co-authored 1 publications receiving 23 citations.

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TL;DR: It was observed, that after conjugation to CdTe QD–streptavidin, the anti-TNase antibody still possesses its bio-recognition specificity and bioactivity, and the use of QD-antibody conjugate as bio-probe for the development of rapid and easy to use onsite detection platforms for infectious agents.
Abstract: Staphylococcus aureus is a major human pathogen that elicits wide range of exo-toxic proteins that are responsible for diverse disease symptoms in humans. In the present study, sensitive and selective monoclonal antibody (mAb) based quantum dot fluorescent sensing platforms were developed for rapid detection of S. aureus , based on thermostable nuclease (TNase). It was observed, that after conjugation to CdTe QD–streptavidin, the anti-TNase antibody still possesses its bio-recognition specificity and bioactivity. Using this modified QD probe, simple to use immune assays such as nitrocellulose paper based dot-assay and fluorescence resonance energy transfer (FRET) assay were developed. Limit of detection (LOD) for the developed methods were stayed as 3 ng/mL for dot assay and 0.5 ng/mL for FRET assay. Developed methods were successfully validated on naturally contaminated samples and they showed a good linearity for calibrated detection of S. aureus in the tested samples. The results articulate the use of QD–antibody conjugate as bio-probe for the development of rapid and easy to use onsite detection platforms for infectious agents. QDs and its modifications were characterized by spectroscopy and microscopy techniques.

29 citations


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TL;DR: The classic and current protocols used to synthesize QDs, as well as the adaptability of QD surfaces for versatile bioconjugation are discussed, aswell as the recent advances in the detection of heavy metal ions, pathogens, and cancer biomarkers are highlighted in this review.
Abstract: Luminescent semiconductor nanocrystals or quantum dots (QDs) provide exquisite electro-optical properties that are ideal for biological sensing applications. Unlike traditional fluorescent dyes that lack in long-term stability and the ability to detect multiple signals simultaneously, QDs have overcome these obstacles, and thus, their potential use as in vivo and in vitro fluorophores has greatly advanced since their discovery in the 1980’s. In this review article, we discuss the classic and current protocols used to synthesize QDs, as well as the adaptability of QD surfaces for versatile bioconjugation. Energy transfer mechanisms represent the basis for the strong attraction of QDs to the biosensing community and thus, we examine the parameters that are required for efficient fluorescence resonance energy transfer, bioluminescence resonance energy transfer, and chemiluminescence resonance energy transfer. In addition, the recent advances in the detection of heavy metal ions, pathogens, and cancer biomarkers are also highlighted in this review. While QDs have shown much progress, the materials selection and commercialization of QDs for biological applications remain an ambitious challenge.

206 citations

Journal ArticleDOI
TL;DR: A review of point-of-care (POC) diagnostics can be found in this paper, where the authors provide new insights and directions for the future development of POC diagnostics for the management of infectious diseases and contribute to the prevention and control of infectious pandemics like COVID-19.

183 citations

Journal ArticleDOI
TL;DR: The perovskite family is comprised of a great number of members because of the possible flexible substitution of numerous ions in its system as discussed by the authors, which essentially boost their properties and largely favor their sensing applications.
Abstract: The perovskite family is comprised of a great number of members because of the possible flexible substitution of numerous ions in its system. These compounds have a broad range of applications due to their outstanding optoelectronic properties in solar cells, photodetectors, lasers, and light-emitting diodes (LEDs). Perovskite nanocrystals (PNCs) are highly tolerant to defects, unlike metal chalcogenides, and do not require surface passivation to retain high quantum yields. Interestingly, the defect structures and trap states in perovskites are often found only in their conduction and/or valence bands and not in the mid-states of the bandgap. Such characteristics essentially boost their properties and largely favor their sensing applications. Perovskites have thus been attempted by numerous groups to address the serious concern of heavy metal ions, biomolecules, and gas molecule detection with high selectivity and sensitivity limits. In this context, the current review describes recent developments and various strategies used in applying perovskites as probes for sensing various contaminants, drugs, and gases in the environment. The focus is on two main aspects: (i) the exploitation of the high fluorescence of these perovskites for optical sensing and (ii) the utilization of the redox ability of these perovskites for electrochemical sensing. This review also outlines the existing challenges, giving future perspectives for developing perovskite-based sensing probes of high sensitivity and enduring stability for a range of environmental analytes.

78 citations

Journal ArticleDOI
TL;DR: A fast, specific and sensitive homogeneous assay for Staphylococcus aureus detection was developed by measuring the activity of secreted nuclease from the bacteria via a modified DNA oligonucleotide, formed by nucleic acid oligos and magnetic or mesoporous silica nanoparticles.

68 citations

Journal ArticleDOI
Xiaoyue Xiao1, Song Hu1, Xiaocui Lai1, Juan Peng1, Weihua Lai1 
TL;DR: This review provided a comprehensive understanding of immunoassays for the detection of hazards in food samples and introduced the developmental trend of traditional immunoASSays systematically.
Abstract: Background A gradual number of hazardous substances may exist in food, posing a threat to consumers health. Traditional immunoassays, such as enzyme-linked immunosorbent assays (ELISA), lateral flow immunoassays (LFI), and chemiluminescence immunoassays (CLI) have been widely applied to analyze different hazards in food samples to ensure food safety. However, due to the low sensitivity and accuracy, the further application of traditional immunoassays was limited. Scope and approach In this review, the classification and potential harm of hazards in food were listed, while the principles and applications of ELISA, LFI, and CLI for the detection of different hazards in food samples were illustrated. Furthermore, to improve the detection performance, such as sensitivity and accuracy, we introduced the developmental trend of traditional immunoassays systematically. This review provided a comprehensive understanding of immunoassays for the detection of hazards in food samples. Key findings and conclusions Recent studies have utilized novel strategies to improve the performance of immunoassays. Typically, creating novel signal labels, and improving the support for signal labels, high-quality monoclonal antibody, specific recognition elements, heterologous detective antigen, and detection platform were comprehensively proposed. The future immunoassays should be ultrasensitive and multiple detection.

53 citations