▎ 摘　　要

NOVELTY - Red luminescent carbon nanostructure comprises red luminescent carbon nanomaterial which is extracted from Mangifera indica leaves as carbon source. USE - Red luminescent carbon nanostructures as graphene quantum dots for biomedical use such as near infrared, bioimaging, intracellular and temperature sensors. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for synthesizing red luminescent carbon nanostructures, which involves: (A) Cutting the mango leaves into tiny pieces, Dispersing the leaves in alcoholic solvent, stirring the mixture and centrifuging the solution, separating supernatant and evaporating solvent from the separated solution to obtain a residue; (B) dispersing the slurry obtained in aqueous medium and heating under microwave oven to obtain grapheme quantum dots; and (C) optionally purifying grapheme quantum dots obtained by dispersing in alcoholic solvent.