Indian Institute of Technology Ropar

About: Indian Institute of Technology Ropar is a education organization based out in Ropar, India. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 1014 authors who have published 2878 publications receiving 35715 citations.

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

Abstract: 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−1. 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.

Anticipating critical transitions in epithelial–hybrid-mesenchymal cell-fate determination

Abstract: In the vicinity of a tipping point, critical transitions occur when small changes in an input condition cause sudden, large, and often irreversible changes in the state of a system. Many natural systems ranging from ecosystems to molecular biosystems are known to exhibit critical transitions in their response to stochastic perturbations. In diseases, an early prediction of upcoming critical transitions from a healthy to a disease state by using early-warning signals is of prime interest due to potential application in forecasting disease onset. Here, we analyze cell-fate transitions between different phenotypes (epithelial, hybrid-epithelial/mesenchymal [E/M], and mesenchymal states) that are implicated in cancer metastasis and chemoresistance. These transitions are mediated by a mutually inhibitory feedback loop—microRNA-200/ZEB—driven by the levels of transcription factor SNAIL. We find that the proximity to tipping points enabling these transitions among different phenotypes can be captured by critical slowing down-based early-warning signals, calculated from the trajectory of ZEB messenger RNA level. Further, the basin stability analysis reveals the unexpectedly large basin of attraction for a hybrid-E/M phenotype. Finally, we identified mechanisms that can potentially elude the transition to a hybrid-E/M phenotype. Overall, our results unravel the early-warning signals that can be used to anticipate upcoming epithelial–hybrid-mesenchymal transitions. With the emerging evidence about the hybrid-E/M phenotype being a key driver of metastasis, drug resistance, and tumor relapse, our results suggest ways to potentially evade these transitions, reducing the fitness of cancer cells and restricting tumor aggressiveness.

Magnetohydrodynamics- and magnetosolutal-transport-mediated evaporation dynamics in paramagnetic pendant droplets under field stimulus.

Abstract: Evaporation kinetics of pendant droplets is an area of immense importance in several applications, in addition to possessing rich fluid dynamics and thermal transport physics. This article experimentally and analytically sheds insight into the augmented evaporation dynamics of paramagnetic pendant droplets in the presence of a magnetic field stimulus. The literature provides information that solutal advection and the solutal Marangoni effect lead to enhanced evaporation in droplets with solvated ions. The main focus of this article is to modulate the thermosolutal advection with the aid of an external magnetic field and comprehend the dynamics of the evaporation process under such complex multiphysics interactions. Experimental observations reveal that the evaporation rate enhances as a direct function of the magnetic moment of the solvated magnetic element ions, thereby pointing at the magnetophoretic and magnetosolutal advection. Additionally, flow visualization by particle image velocimetry illustrates that the internal advection currents within the droplet increase in magnitude and are distorted in orientation by the magnetic field. A mathematical formalism based on magnetothermal and magnetosolutal advection has been proposed via scaling analysis of the species and energy conservation equations. The formalism takes into account all major governing factors, viz., the magnetothermal and magnetosolutal Marangoni numbers, magneto-Prandtl and magneto-Schmidt numbers, and the Hartmann number. The modeling establishes the magnetosolutal advection to be the dominant factor behind the augmented evaporation dynamics. Accurate validation of the experimental internal circulation velocity is obtained from the proposed model. This study reveals rich insight into the magnetothermosolutal hydrodynamics in paramagnetic droplets.

Development of chemosensor for Sr2+ using organic nanoparticles: application of sensor in product analysis for oral care

Abstract: A new series of compounds has been developed for the recognition of metal ions and it was found that the position of substituent in the organic compound proved to be the deciding factor for the development of a chemosensor. Reprecipitation method was used to develop organic nanoparticles (ONPs) in aqueous medium and the suspension of ONP in aqueous medium remained stable for one month. These ONPs were studied for their recognition abilities using fluorescence spectroscopy and only ONPs of compound 1 resulted in a sensor for Sr2+ and the sensor activities were found to be unaffected by the presence of any other cation. The sensor was successfully used to investigate the level of Sr2+ in an oral gel, as well as toothpastes used to cure sensitive teeth.