Green-Synthesized Chaenomeles speciosa-Derived Carbon Quantum Dots with Blue Fluorescence and Selective Pro-Apoptotic Effects in Cancer Cells.

Carbon nanodots were synthesized from Chaenomeles speciosa flowers and comprehensively characterized. UV-Vis analysis revealed a broad absorption band from 200 to 400 nm, attributed to π→π* (200-250 nm) and n→π* (250-350 nm) transitions, while fluorescence under 365 nm excitation showed bright blue emission. HRTEM images indicated spherical nanoparticles forming clustered aggregates, with lattice fringes exhibiting interplanar spacings of 0.091-0.093 nm, confirming a partially graphitic structure. XRD analysis showed a broad amorphous baseline in the 10-40° 2θ range, indicating low crystallinity. FTIR and XPS analyses identified abundant surface -OH, C = O, and C-O groups, with elemental composition of C 68.28%, O 23.03%, N 6.70%, S 0.40%, and Si 1.59%, resulting in a C/O ratio of 2.97. Chaenomeles speciosa quantum dots (CS-CQDs) exhibited dose-dependent cytotoxicity in MDA-MB-231 cells (viability: 70% at 2.5 mg/mL, 60% at 5 mg/mL) and HeLa cells (approximately 50% at 2.5-5 mg/mL), with minimal effects on hTERT-HME1 cells (viability greater than 85% at 0.6 mg/mL). Apoptosis increased from 25% to 55% in MDA-MB-231, from 24% to 65% in HeLa, and from 5.9% to 25% in HME1, with negligible necrosis. Gene expression analyses showed NF-κB upregulation (3-fold in MDA-MB-231; 6-fold in HeLa), BAX and BCL-2 upregulation in HeLa (approximately 2.5-fold), and downregulation of HIF1A, IL-6, MMP2, and MMP9. Wound healing assays indicated reduced migration in MDA-MB-231 (44% to 21%), increased migration in HeLa (18.7% to 30%), and minimal change in HME1 (73.5% to 71.5%). These results demonstrate that CS-CQDs possess favorable optical and structural properties and selectively induce apoptosis in cancer cells, with minimal impact on non-cancerous cells, highlighting their potential as targeted anticancer nanomaterials.