Publications by authors named "Satheesh Natarajan"

Accurate quantification of immunoglobulin G (IgG) levels is vital for understanding immune status and diagnosing various medical conditions. Lateral flow assays (LFAs) offer rapid and convenient diagnostic tools, but their sensitivity has been a limitation. Our research introduces a refined method incorporating europium nanoparticles, enhancing both sensitivity and accuracy of LFAs in human IgG measurement.

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The clinical manifestation of leptospirosis is often misdiagnosed as other febrile illnesses such as dengue. Therefore, there is an urgent need for a precise diagnostic tool at the field level to detect the pathogenic gene at the molecular level for prompt therapeutic decisions. Quantitative polymerase chain reaction (qPCR) is widely used as the primary diagnostic tool, but its applicability is limited by high equipment cost and the lack of availability in every hospital, especially in rural areas where leptospirosis mainly occurs.

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This paper presents a lateral flow assay (LFA) for the quantitative, fluorescence-based detection of the kidney biomarker cystatin C that features conjugates of capture antibodies and fusions of carbohydrate binding modules (CBM) with ZZ domains anchored on cellulose deposited over nitrocellulose (NC). The ZZ-CBM3 fusion provides a biomolecular interface between the cellulose layer and the Fc portion of the capture antibodies. By resorting to detection Fab fragments that lack the Fc portion we overcome the observed interference of full-length detection antibodies with the ZZ-CBM3 fusion at the test lines.

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This study aimed to establish a Europium label time-resolved fluorescence immunoassay (TRFIA) to detect the chronic kidney disease (CKD) biomarker Cystatin-C. An Europium based Time resolved fluorescence immunoassay was developed to detect the concentration of Cystatin-C in a urine sample to increase the sensitivity with captured anti-Cystatin-C antibodies immobilized on nitrocellulose membrane and then bonded with detection anti-Cystatin-C labelled with CM-EU, followed by fluorescence measurement using time-resolved fluorometry in 15 min. The performance of this TRFIA was evaluated using the clinical urine serum and compared with the ELISA assays.

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In March 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-based infections were declared 'COVID-19 pandemic' by the World Health Organization. Pandemic raised the necessity to design and develop genuine and sensitive tests for precise specific SARS-CoV-2 infections detection. Nanotechnological methods offer new ways to fight COVID-19.

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Article Synopsis
  • * A new, quick immunoassay using a fluorescence-based lateral-flow kit has been developed to measure cystatin-C, offering a linear calibration range and low limits of detection and quantification.
  • * This kit shows high sensitivity, excellent repeatability, and can be easily used at point-of-care settings, making it suitable for rapid screening of kidney function disorders in the community.
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A wide range of microorganisms can infect the central nervous system (CNS). The immune response of the CNS provides limited protection against microbes penetrating the blood-brain barrier. This results in a neurological deficit and sometimes leads to high morbidity and mortality rates despite advanced therapies.

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This paper presents a lateral flow assay (LFA) for the quantitative, fluorescence-based detection of the cardiac biomarker troponin I (cTnI) that features an analytical strip made of cellulose filter paper. The results show that the wicking and test time are comparable to those obtained with conventional nitrocellulose (NC)-based LFAs. Further, the cellulose paper provides an excellent background with no auto-fluorescence that is very adequate in detecting fluorescent lines.

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In the emergency diagnosis of patients, acute myocardial infarction (AMI) is always time-consuming to diagnose, and the process requires multiple laboratory procedures, expensive equipment and skilled workers. Herein, we developed an easy-to-use, low-cost and portable fluorescent lateral flow immunoassay based on paper microfluidics for the point-of-care diagnostics of non-communicable diseases. The fluorescent lateral flow immunoassay can produce results in less than 10 minutes, and the limit of detection (LOD) is 0.

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Human immunodeficiency virus (HIV) infections in sub-Saharan Africa represent about 56% of global infections. Many studies have targeted HIV-1 protease for the development of drugs against AIDS. Recombinant HIV-1 protease is used to screen new drugs from synthetic compounds or natural substances.

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An amino acid Schiff base (R) capable of recognizing Zn(2+) ions selectively and sensitively in an aqueous medium was prepared and characterized. Upon addition of Zn(2+) ions, the receptor exhibits fluorescence intensity enhancements (~40 fold) at 460 nm (quantum yield, Φ=0.05 for R and Φ=0.

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Several protein expression systems for construction of protein arrays have been established in recent years. However, current protocols for protein synthesis are still time consuming, laborious and expensive. This study has established an alternative workflow that covers rapid construction of expression cassettes, in-tube and on-membrane synthesis of recombinant proteins, and straightforward screening of synthesized proteins.

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A melt dispersion technique was employed to prepare ofloxacin lipospheres, by using cetyl alcohol (polar lipid). Effects of various process parameters such as selection of surfactants (gelatin, Tween 40 and poly vinyl alcohol) and selection of stirring speed were studied. Lipospheres were evaluated for morphology, drug entrapment and in vitro drug release profiles.

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The development of novel therapeutic agents is essential for combating the increasing number of cases of dengue fever in endemic countries and among a large number of travelers from non-endemic countries. The dengue virus has three structural proteins and seven non-structural (NS) proteins. NS3 is a multifunctional protein with an N-terminal protease domain (NS3pro) that is responsible for proteolytic processing of the viral polyprotein, and a C-terminal region that contains an RNA triphosphatase, RNA helicase and RNA-stimulated NTPase domain that are essential for RNA replication.

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The main task in the development of transgenic plants is the capability to distinguish between plant cells with an integrated transgene and the bulk of non-transformed cells. Selectable marker genes are required to achieve this goal within the transgene, and to select for their expression. These selectable markers are mostly based on genes conferring antibiotic or herbicide resistance.

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Genetically modified (GM) foods are the product of one of the most progressive fields of science-biotechnology. There are major concerns about GM foods in the public; some of them are reasonable, some of them are not. Biomedical risks of GM foods include problems regarding the potential allergenicity, horizontal gene transfer, but environmental side effects on biodiversity must also be recognized.

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