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

Kavitha Shivaji, Mythili Gnanamangai Balasubramanian, Anitha Devadoss, Vijayshankar Asokan, Catherine Suenne De Castro, Matthew Lloyd Davies, Ponnusammy Ponmurugan, Sudhagar Pitchaimuthu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


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 bio-surfactant 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.

Original languageEnglish (US)
Pages (from-to)159-170
Number of pages12
JournalApplied Surface Science
StatePublished - Sep 1 2019

Bibliographical note

Funding Information:
The authors KS and MGB thank the Principal and Head, Department of Biotechnology, K.S. Rangasammy College of Technology, Tiruchengode, Tamil Nadu, India for the support offered towards study. These authors also acknowledge DST-FIST (fund for infrastructure) for science and technology (SR/FST/College-235/2014 dated 21.11.2014). S.P. acknowledges Welsh Government and European Regional Development Fund (ERDF) for supporting Rising Star Fellowship. A.D acknowledges Ser Cymru II MSCA COFUND Fellowship jointly funded by Welsh Government and European Commission through ERDF funds. MLD and CD are grateful for the financial support of the EPSRC ( EP/R016666/1 and EP/S001336/1 ) and both the EPSRC and Innovate UK for the SPECIFIC Innovation and Knowledge Centre and for the support from the European Regional Development Fund through the Welsh Government to the Sêr Solar program. All authors thank to Kanan Devan Hills plantations company (p) ltd, Munnar, Kerala, for their constant support.

Publisher Copyright:
© 2019 Elsevier B.V.


  • Apoptosis
  • Breast cancer
  • CdS
  • Cytotoxicity
  • Green synthesis
  • Quantum dots
  • Waste tea leaves

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • General Physics and Astronomy
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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