Introduction: Triple-negative breast cancer (TNBC) accounts for approximately 15-20% of all breast cancers and is prevalent among younger women. Due to the lack of specific receptors, treatment options are limited. Metastatic TNBC has a dismal prognosis with an overall survival rate of only 13 months due to drug resistance. Thus, there is an urgent need for new drug delivery systems to improve the therapeutic modality of TNBC. We have synthesized carbon quantum dots (CQDs) from biowaste, leveraging anti-proliferative effects on TNBC cells.

Methods: CQDs were synthesized by a hydrothermal process from garlic peel and mango leaves in a 1:1 proportion using a stainless-steel autoclave lined with poly(tetrafluoroethylene) (PTFE), heated at 180 °C for 4h under autogenous pressure and filtered. The obtained filtrate was sonicated for 2h and dried in a hot-air oven to produce CQDs. A morphological evaluation and MTT assay of CQD on NIH3T3, MCF7, and MDA MB 231 cells were performed.

Results and Discussion: The microscopic evaluation of NIH3T3 cells exhibited no morphological changes up to 500 µg/ml, whereas MCF7 and MDA MB 231 cells showed morphological changes from concentrations of 100 µg/mL and 50 µg/mL, respectively. Moreover, the MTT assay revealed increased cytotoxicity from day 3 onwards in both the cell lines, more significantly in MDA MB 231.

Conclusions: The CQDs synthesized using biowaste are biocompatible with non-cancerous NIH3T3 cells, whereas they exhibit anticancer activity on breast cancer cell line MCF7 and triple-negative breast cancer cells MDA MB 231. Hence these CQDs can extend the arsenal of functional anti-cancer materials for the targeted therapy of TNBC suffering patients.