Fig. 1

NanoGO and NanoGO-MB ultrastructure and characterization. A Oxygenated groups of GO and carboxylated NanoGO indicated on the FTIR with the prominence of the carboxylic acid group in 1728 cm⁻¹ in carboxylated GO (red), suggesting successful carboxylation. B UV–Vis of samples showing the loading of MB into NanoGO sheets once its characteristic absorption peak at ~ 660 nm is visible on sample NanoGO-MB. C Methylene blue release kinetics from NanoGO under different pH conditions on PBS 10% FBS. The higher amount of MB released in a more acidic pH results from a weaker electrostatic interaction between the negatively charged carboxylic acid groups from NanoGO and the positively charged MB. D On the TEM image, arrows indicate the boundaries of the graphene oxide nanosheets, magnification of ×100,000 (scale bar = 2 µm). E SEM image reveals the sheet-like shape and of GO, magnification of ×230 (scale bar = 100 µm). F Real time-infrared camera showing NanoGO temperature variation after irradiation with 808 nm NIR laser light. G Water and graphene oxide after irradiation with 808 nm NIR laser light for 10 min (fluency of 5.52 kJ cm⁻²). NanoGO temperature variation of ~ 40 °C. H DPBF absorbance decay of free MB and NanoGO-MB upon irradiation with 660 nm LED light