Utilization of waste tea leaves as bio-surfactant in CdS quantum dots synthesis and their cytotoxicity effect in breast cancer cells
Journal article, 2019

Green technology for nanoparticles synthesis is considered to be of great significance in biomedical applications. Recently, low dimensional semiconductor cadmium sulfide (CdS) quantum dots (QDs) have raised great attention due to their optical properties and wide usage in biomedical studies. In our present work, we demonstrate a simple green synthesis route for CdS QDs production using waste matured tea leaves (mother leaf) as biosurfactant that are a waste product of the tea leaf industry and not suitable for drinking. The structural and morphological analysis showed waste tea leaf derived CdS QDs range from 2.5 to 4 nm in particle size with a cubic crystalline structure. Interestingly, these CdS QDs exhibit strong fluorescence emission with maximum around 670 nm. We explored the cytotoxic effect of waste tea leaf mediated CdS QDs (MT-CdS QDs) in breast cancer cell lines and compared their viability with standard drug - cisplatin. Our experimental studies strongly suggest that MT-CdS QDs exhibits cytotoxic effect on breast cancer cells and their performance was compared with standard drug cisplatin. To further understand the role of MT-CdS QDs towards cytotoxicity, the fluorescence microscopy and flow cytometry analysis were carried out. The flow cytometry results reveal that MT-CdS QDs induces cell death as it arrests the cell cycle at S phase as well as G2/M phase. Further the apoptosis mechanism was confirmed with the expression of anti-apoptotic and apoptotic proteins. These studies explored that waste tea leaves have dual advantage - both in controlling the particle size of CdS QDs as well as facilitates their cytotoxicity effect in breast cancer cell death. Therefore, it is anticipated that the utilization of MT-CdS QDs produced from waste tea leaves as bi-functional drug and delivery vehicle in cancer treatment will be a promising approach. Also, this is a simple and circular economic route for producing biocompatible QDs at low-cost, which could simultaneously benefit tea and biomedical industries.


Quantum dots

Waste tea leaves

Green synthesis

Breast cancer




Kavitha Shivaji

K.S. Rangasamy College of Technology

Mythili Gnanamangai Balasubramanian

K.S. Rangasamy College of Technology

Anitha Devadoss

Swansea University

Vijayshankar Asokan

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Catherine Suenne De Castro

Swansea University

Matthew Lloyd Davies

Swansea University

Ponnusammy Ponmurugan

Bharathiar University

Sudhagar Pitchaimuthu

Swansea University

Applied Surface Science

0169-4332 (ISSN)

Vol. 487 159-170

Subject Categories

Cell Biology

Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)

Other Industrial Biotechnology



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