Cocoa Pod Husks as Precursors for Biosynthesis of Carbon Dots as Potential Bioimaging Tool

Document Type : Research Paper


1 Biophysics Laboratory, Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

2 Nanomaterial Synthesis and Characterization Lab, Institute of Nanoscience and Nanotechnology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

3 Malaysian Cocoa Board, 5 – 7th Floor, Wisma SEDCO, Lorong Plaza Wawasan, Off Coastal Highway, Locked Bag 211, 88999 Kota Kinabalu, Sabah, Malaysia

4 Department of Chemistry, Universiti of Malaya, 50603 Kuala Lumpur, Malaysia

5 Department of Materials Science, Faculty of Engineering, Kyushu Institute of Technology, Tobata Campus, 1-1 Sensui-cho, Tobata-ku, Kitakyushu-shi, Fukuoka, 804-8550, Japan

6 UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia


   Recent zero-dimensional carbon dots (CDs) have dominated the world of nanomaterials due to their ease of synthesis and nature of their precursors. The aim of this study is to synthesize, characterize and evaluate cytotoxicity of CDs from agricultural waste CPH for its potential use in the bioimaging field. The TEM analysis and particle size distribution curve revealed that the particles had a diameter of 10-30 nm, sphere-shaped and exhibited lattice fringes with a d-spacing of 0.196 nm. XRD analysis revealed a broad peak at 2Ɵ = 20.71°, indicating the existence of carbon. FTIR confirmed the presence of multiple functional chemical groups on the surface of the CPH CDs consist of C=O, N–H, C–N, and C–O–C. Due to the electronic transition’s characteristic of CDs, the UV-Vis absorption spectrum revealed two distinct peaks at 235 and 293 nm.  PL spectra of CPH CDs revealed a red shift in the emission peak from 400 to 410 nm as the excitation wavelength increased from 320 to 380 nm. We used brine shrimp and human colon adenocarcinoma cells (Caco2) in vitro to determine the cytotoxicity of CPH CDs. In terms of brine shrimp assay, we found that 0.001 mg/ml showed lower lethality percentage with 57.93 ± 9.77 %.  The cytotoxicity of CPH CDs was assessed in vitro using the MTT assay and Caco2 cell line's viability decreased with increasing concentration (IC50 = 155 ug/ml). Due to their favorable properties and low cytotoxicity, CPH CDs have the potential to be used as bioimaging tools.


Main Subjects

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