Publications by authors named "Jagpreet Singh Sidhu"

6 Publications

  • Page 1 of 1

Trends in small organic fluorescent scaffolds for detection of oxidoreductase.

Biosens Bioelectron 2021 Nov 15;191:113441. Epub 2021 Jun 15.

Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India. Electronic address:

Oxidoreductases are diverse class of enzymes engaged in modulating the redox homeostasis and cellular signaling cascades. Abnormal expression of oxidoreductases including thioredoxin reductase, azoreductase, cytochrome oxidoreductase, tyrosinase and monoamine oxidase leads to the initiation of numerous disorders. Thus, enzymes are the promising biomarkers of the diseased cells and their accurate detection has utmost significance for clinical diagnosis. The detection method must be extremely selective, sensitive easy to use, long self-life, mass manufacturable and disposable. Fluorescence assay approach has been developed potential substitute to conventional techniques used in enzyme's quantification. The fluorescent probes possess excellent stability, high spatiotemporal ratio and reproducibility represent applications in real sample analysis. Therefore, the enzymatic transformations have been monitored by small activatable organic fluorescent probes. These probes are generally integrated with enzyme's substrate/inhibitors to improve their binding affinity toward the enzyme's catalytic site. As the recognition unit bio catalyzed, the signaling unit produces the readout signals and provides novel insights to understand the biochemical reactions for diagnosis and development of point of care devices. Several structural modifications are required in fluorogenic scaffolds to tune the selectivity for a particular enzyme. Hence, the fluorescent probes with their structural features and enzymatic reaction mechanism of oxidoreductase are the key points discussed in this review. The basic strategies to detect each enzyme are discussed. The selectivity, sensitivity and real-time applications are critically compared. The kinetic parameters and futuristic opportunities are present, which would be enormous benefits for chemists and biologists to understand the facts to design and develop unique fluorophore molecules for clinical applications.
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http://dx.doi.org/10.1016/j.bios.2021.113441DOI Listing
November 2021

A highly selective naphthalimide-based ratiometric fluorescent probe for the recognition of tyrosinase and cellular imaging.

Analyst 2018 Sep 29;143(18):4476-4483. Epub 2018 Aug 29.

Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.

Tyrosinase is polyphenolic oxidase enzyme associated with the progression of various diseases. Therefore, for the recognition of tyrosinase, naphthalimide-based ratiometric fluorescent sensor probe was designed and synthesized. 3-Hydroxyphenyl, as the substrate unit for the enzyme, is an important feature of this design, which avoids the interference of other bio-analytes for the recognition of tyrosinase. When the sensor probe was excited at 425 nm, an intense blue emission band emerged at 467 nm. However, upon the addition of tyrosinase to the probe solution, the monophenolic unit oxidized to o-dihydroxy and consequently released the 4-aminonaphthalimide unit. As the oxidation reaction proceeded, the fluorescence emission at 535 nm started to increase gradually with an increase in the concentration of enzyme. Therefore, the sensor probe gives the ratiometric changes via fluorescence spectroscopy. The probe affords high selectivity and sensitivity to tyrosinase with a detection limit of 0.2 U mL. Furthermore, live cell images were recorded to assay the endogenous enzyme in A375 cells, which also show a dual color change in the presence of the L3 probe.
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http://dx.doi.org/10.1039/c8an01136bDOI Listing
September 2018

FRET and PET paired dual mechanistic carbon dots approach for tyrosinase sensing.

J Mater Chem B 2018 Jun 8;6(24):4139-4145. Epub 2018 Jun 8.

Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.

A dual mechanistic FRET and PET paired ratiometric fluorescence sensor probe has been prepared using carbon dots and naphthalimide fluorophores. The carbon dots are covalently joined with a naphthalimide moiety to develop the FRET phenomenon, which emits at two different wavelengths (i.e., λ = 440 and 540 nm). However, on catalytic reaction of tyrosinase, the fluorescence emission intensity of the acceptor unit at 540 nm is quenched gradually, owing to the switching on of the PET mechanism; while emission of the donor unit remains significantly unaffected. The probe exhibits high selectivity and specificity towards tyrosinase in complex biological medium with a detection limit of 1.2 U mL. Moreover, endogenous images of tyrosinase in B16 cells have been observed under a confocal laser-scanning microscope.
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http://dx.doi.org/10.1039/c8tb00512eDOI Listing
June 2018

Carbon dots as analytical tools for sensing of thioredoxin reductase and screening of cancer cells.

Analyst 2018 Apr;143(8):1853-1861

Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.

Thioredoxin Reductase (TrxR) is a redox regulating enzyme which is predestined for the maintenance of redox homeostasis of mammalian cells. However, the elevated level of TrxR is associated with the progress of various types of tumors and therefore, this is a significant target for the detection of cancer cells. Herein, an easily engineered 'Turn ON' fluorescent sensor probe has been synthesized for the detection of TrxR and cell imaging using carbon dots. The emission intensity of fCDs on complexation with Cu2+ ions was drastically quenched. Subsequently, the addition of TrxR to the solution of the fCDs-Cu2+ complex leads to the cleavage of the disulfide bond of the fCDs, which acclaim the release of 3-mercaptopropionic acid. 3-Mercaptopropionic acid, being a strong bi-dentate chelating agent for Cu2+ ions, extracted Cu2+ from the coordination sphere of fCDs and restored the original fluorescence intensity of fCDs. Thus, the probe is operating with a simple process of "ON-OFF" emission switching due to Cu2+ and "OFF-ON" switching with TrxR. The probe has been successfully used for real-time application to monitor TrxR activities in the complex biological system. The fluorescence images of MCF-7 and HeLa cells after incubation with the fCDs-Cu2+ complex were recorded under a confocal laser scanning microscope (CLSM) as a function of time. Enhancement in the emission intensity of cancer cells after 2 h of treatment demonstrates the potential application of the sensor probe for the bioimaging of endogenous TrxR in living cells and screening of cancer cells. Such fluorescent probes will open the door for the development of promising clinical devices for the diagnosis of cancer cells.
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http://dx.doi.org/10.1039/c7an02040fDOI Listing
April 2018

Carbon Dot Based, Naphthalimide Coupled FRET Pair for Highly Selective Ratiometric Detection of Thioredoxin Reductase and Cancer Screening.

ACS Appl Mater Interfaces 2017 Aug 31;9(31):25847-25856. Epub 2017 Jul 31.

Department of Chemistry, Indian Institute of Technology Ropar , Rupnagar, Punjab 140001, India.

The fluorescence resonance energy transfer (FRET) mechanism has been established between carbon dots (CDs) and naphthalimide to monitor the activity of thioredoxin reductase (TrxR), which is often overexpressed in many cancer cells. The naphthalimide moiety was covalently attached to the surface of CDs through a disulfide linkage. In normal cell conditions (when devoid of high concentrations of TrxR), the CDs act as an energy donor and naphthalimide acts as an acceptor, which establishes the FRET pair as interpreted from the emission at λ = 565 nm, when excited at λ = 360 nm. However, contrary to this, the elevated levels of TrxR cause the breakage of disulfide bonds and consequently abolishes the FRET pair through the release of the naphthalimide moiety from the surface of CDs. This process was studied by monitoring of fluorescence intensity at λ = 565 and 440 nm, when excited at the same wavelength (λ = 360 nm). The TrxR based ratiometric quenching and enhancement of fluorescence intensity offers an interesting opportunity to monitor the enzyme activities and has many advantages over conventional monitoring of fluorescence intensity at a single wavelength to avoid interference of external factors. Fluorescence images of cancer cells in response to the nanosensor were visualized under a confocal microscope. Cytotoxicity study of nanosensor retards the growth of HeLa and MCF-7 cell lines in the presence of visible light. Therefore, the nanosensor also acts as a theranostic agent to diagnose as well as killing of cancer cells.
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http://dx.doi.org/10.1021/acsami.7b07046DOI Listing
August 2017

Indole Derivatives as Anticancer Agents for Breast Cancer Therapy: A Review.

Anticancer Agents Med Chem 2015 ;16(2):160-73

Centre for Chemical and Pharmaceutical Sciences, Central University of Punjab, Bathinda (Pb), India-151001.

Breast cancer (BC) is the second most common cause of cancer-related deaths in women throughout the world. Multiple drugs have been approved by US-FDA for breast related malignancies. Frequent emergence of resistances creates the severe need of newer moieties that are free from such problems. Drugs targeting breast cancer have been observed to be based on the multiple mechanisms of action, and various indole based anticancer agents have also been explored. Moreover, indoles have promising anti-cancer potential; there has been the emphasis on the synthesis of indole derivatives to overcome problems faced by existing therapeutic agents. Taking into consideration the above-mentioned facts we have analyzed in detail the possible role of indole based anticancer agents typically for breast related malignancies. This is the first exhaustive review that jointly covers various synthetic anticancer indole derivatives and related signaling pathways by which these derivatives have shown promising anti-breast cancer potential.
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http://dx.doi.org/10.2174/1871520615666150520144217DOI Listing
August 2016
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