Amit Kumar Sonker

Pollutant soot of diesel engine exhaust transformed to carbon dots for multicoloured imaging of E. coli and sensing cholesterol

A convenient method for the synthesis of water soluble, fluorescent carbon dots from environmental pollutant diesel soot is described. The soot, generated from the exhaust of diesel engines as black, diesel particulate matter (DPM), is an environmental pollutant. This pollutant has been utilized as the precursor carbon source to create water soluble versions of carbon dots by chemical oxidation. The small sized water soluble carbon dots once separated display multicoloured emissions covering the green to red and extended to the near-infrared region. These have been used in imaging Escherichia coli and further used in sensing cholesterol.

Large-scale synthesis of soluble graphitic hollow carbon nanorods with tunable photoluminescence for the selective fluorescent detection of DNA

Photoluminescent water-soluble hollow carbon nanorods were synthesized by the pyrolysis of castor oil seeds (Ricinus communis) without the use of a catalyst. Oxidation of the pyrolysed soot produced a water-soluble form of graphitic hollow carbon nanorods. These showed excitation-dependent multicoloured photoluminescent emission from the green to red region of the visible spectrum and extending to the near-infrared region. This photoluminescent behaviour was used to produce a fluorescent turn-off/turn-on sensor for the specific, sensitive and rapid determination of DNA with a detection limit of ∼1.14 nM.

Crosslinking of agar by diisocyanates.

In the present study, crosslinking of agar using diisocyanate (DI) was demonstrated to limit the high water absorption property of agar. In addition, the efficacy of aromatic diisocyanate, DDI (4, 4 diphenyl diisocyanate) and aliphatic diisocyanate, HDI (1, 6 hexamethylene diisocyanate) on crosslinked agar properties was compared. The water uptake was successfully reduced by crosslinking and its minimum values observed for DDI and HDI crosslinked agar was 33.6% and 43.6%, respectively in comparison to agar (206%). The maximum tensile strength was observed for DDI crosslinked agar (45.3 MPa) which was higher than HDI crosslinked agar (30.6 MPa) and agar (31.7 MPa). The aromatic diisocyanates crosslinked agar showed better thermal resistance at higher temperature. It was observed that aromatic diisocyanate crosslinked agar more effectively than the aliphatic diisocyanate due to the higher reactivity. The crosslinked agar samples were hemocompatible and show non-toxic nature for cell proliferation.