One‐Step Microwave Approach to Generate Carbon Dots/Gelatin Composite with Both Thermoresponsive Sol–Gel Transition and Fluorescence Properties

Abstract

Carbon dots (CDs) have drawn considerable research interest for their attractive applications in sensors, bioimaging, and photonic devices. Here, an aqueous gelatin solution is employed as the only reactant to directly generate a CDs/gelatin composite through a green and simple one‐step microwave approach. The resulting CDs/gelatin composite owns a typical excitation‐dependent photoluminescence property that comes from CDs, which can be potentially applied for multicolor fluorescence bioimaging. More importantly, the CDs/gelatin composite possesses a thermoresponsive sol–gel transition property that is associated with gelatin, which can be exquisitely enlisted to fabricate CDs/gelatin gel beads and fluorescent gel patterns. Also the release of CDs from the gel beads can be triggered by the thermoresponsive sol–gel transition. Thus, for the first time this study creates the CDs/gelatin composite with both thermoresponsive sol–gel transition and fluorescence properties, which is promising for applications in stimuli‐responsive materials, nanocomposites, controlled release, and fluorescence imaging.

Rapid and Green Fabrication of Carbon Dots for Cellular Imaging and Anti-Counterfeiting Applications

“…The chemical compositions of the achieved CDs were measured by Fourier transform infrared spectra (FTIR) together with X-ray photoelectron spectra (XPS) analysis. As exhibited in Figure , the characteristic absorption peak at 3293 cm –1 is from O–H/N–H, 1631 cm –1 is for the stretching vibration band of CO, and 1080 and 874 cm –1 come from the stretching vibration band of C–O, which all indicate that the surface of CDs has been partially oxidized. , Furthermore, the obvious peak at 1540 cm –1 can be associated with N–H bands of vibration and deformation, which manifested that there are some amino-related groups on the CDs. Moreover, the absorption peaks at 1249 cm –1 can be ascribed to the symmetrical stretching vibration band of C–C, and the anti-symmetrical stretching vibration band of C–C is seated at 1029 cm ‑1 . , Additionally, the peaks at 2940 and 1405 cm –1 are assigned to the stretching vibrations C–H and CC, which further suggests the production of alkyl and aryl groups on their surface …”

“…As exhibited in Figure 3, the characteristic absorption peak at 3293 cm −1 is from O−H/N−H, 1631 cm −1 is for the stretching vibration band of CO, and 1080 and 874 cm −1 come from the stretching vibration band of C−O, which all indicate that the surface of CDs has been partially oxidized. 27,28 Furthermore, the obvious peak at 1540 cm −1 can be associated with N−H bands of vibration and deformation, which manifested that there are some aminorelated groups on the CDs. Moreover, the absorption peaks at 1249 cm −1 can be ascribed to the symmetrical stretching vibration band of C−C, and the anti-symmetrical stretching vibration band of C−C is seated at 1029 cm -1 .…”

“…The obtained CDs were prepared from gelatin through simple processing in water without adding any catalyst, acid, or alkali solvents. Moreover, the CDs exhibited excellent water dispersibility, splendid biocompatibility, and remarkable fluorescent properties, which were promising for bioimaging and anti-counterfeiting applications. − As far as we know, the sonochemical-assisted method for rapidly synthesizing nitrogen-doped CDs from gelatin has never been reported before. Significantly, the sonochemical-assisted approach to rapidly fabricate CDs is versatile for the facile construction of fluorescent CDs from many analogous carbon sources.…”

Hierarchical Porous Aerogels With Multiple Adsorptive Interactions for Dye Wastewater Purification

“…Gelatin exhibits a reversible sol‐gel transition under temperature changes. It forms a gel when the temperature falls below 37 °C and returns to a solution when the temperature rises above the melting temperature [24] . The sol‐gel property as well as the hydrophilicity of the gelatin make it facile to prepare gelatin‐based aerogels, and the as‐prepared aerogels possess excellent dye adsorption ability [25,26] .…”

Turning Waste into Treasure: Multicolor Carbon Dots Synthesized from Waste Leather Scrap and their Application in Anti-Counterfeiting

“…Hashemi and Mousazadeh used red beetroot as a precursor to prepare CDs with a size of 5–7 nm . Studies using amino acid, , hair hemicellulose, gelatin, and algae to prepare CDs, have proved that biomass materials containing proteins or amino acids are good choices. Adjusting the fluorescence properties of CDs to obtain different luminescence colors has been widely studied, but biomass material-based CDs need to be investigated in depth.…”