Fig. 2
(a) UV-Vis (300 to 1000 nm) absorption spectroscopic analysis of the formation of polypyrrole (PPy) using ferric chloride. (b) Fourier transform infrared (FTIR) results showing the chemical structure of the prepared samples. (c) Results of temperature changes of the test liquid formulation after NIR treatment showing quantitative analysis with a thermocouple (TM-925, Lutron) until the temperature reached 25 °C, and a qualitative image of these aqueous formulations with a thermal camera (A-BF, RX300, China) at 808 nm and 2.0 W/cm2 (scale bar: 6 mm). (d) Polydispersity index (PDI) and (e) TEM (scale bar: 100 nm) results showing morphological changes of the spherical core-shell structure of the nano-formulation with colloidal stability (PBS or PBS plus 10% FBS at pH 7.4 for 7 days). After laser irradiation, the TEM image shows particle disruption and aggregation (scale bar: 1000 nm). (f) Spectrophotometric analysis showing the release of dipyridamole (DIP) from the nanoparticles (NPs) under PBS. Under irradiation with NIR light, the photothermal effect of the DIP-fucoidan (FU)-PPy NPs triggered the morphological transformation of the polymeric carrier, which allowed the DIP to be released from the NPs