Applied Nanoscience (Switzerland), cilt.13, sa.9, ss.6667-6696, 2023 (SCI-Expanded)
The aim of this study was to design and characterize a candidate molecule of biological significance by synergistically combining the unique chemical properties, biocompatibility, and low toxicity of carbon quantum dots (CNDs) by the precursor molecule o-phenylenediamine (o-PDA), which is used to produce most chemotherapeutic agents, as a CNDs/o-PDA conjugate. Using citric acid (CA), surface-functional CNDs were synthesized by simple and rapid thermal pyrolysis for 2 h at 180 °C without using chemicals. Conjugation was carried out for 16 h at 40 °C in N,N-dimethylformamide (DMF) presence of triethylamine (Et3N). Structural characterizations were performed by spectroscopic techniques such as attenuated total reflectance—Fourier transform infrared (ATR-FTIR), nuclear magnetic resonance (1H-NMR), UV–Vis, and fluorescence spectroscopy. The crystal structure of pure- and o-PDA-conjugated-CNDs was characterized using X-ray diffractometers (XRD-MF). Physical characterizations were performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Q-TOF LC/MS (liquid chromatography–quadrupole-time-of-flight mass spectrometry) and size exclusion chromatography (SEC) were used to analyze molecular weight change and polydispersity index (PDI) as a result of o-PDA conjugation. The spherical nanoparticle size of the nanodots was confirmed by transmission electron microscopy (TEM). All results suggest that the targeted o-PDA derivatization of CNDs was successfully achieved by the ring-opening reaction.