Luminescent nanoparticles from cocoa pod husks as bioimaging tools

Introduction: This study conducted was to investigate the properties of the nanomaterials known as luminescent nanoparticles (LNPs). These LNPs was synthesized with an organic precursor known as cocoa pod husk (CPH). Malaysia has a large agricultural potential that can support economic activity. Rubber, palm oil, and cocoa are major agricultural export in Malaysia. Polyphenols are naturally occurring antioxidants found in foods like fruits and vegetables. They have been linked to numerous health benefits. Luminescent nanoparticles (LNPs) have attracted a great attention of researchers in the current era due to their unique properties. Though, the top-down synthesis of LNPs has always been one of the most preferred method to obtain LNPs in significant yields.

Methods: The LNPs used in this process could be obtained by a green approach such as the one-step hydrothermal method. The top-down synthesis method of LNPs has side effects such as toxicity which are still a major concern while using as pharmaceutical excipients or drug delivery transporter. Owing to that, herein we proposed green LNPs from agricultural waste for bio-applications. Green technology opens new windows as there are readily available, renewable, economic and environmental-friendly. 

Results & Discussions: The synthesis, structural and optical properties, as well as photoluminescence mechanisms of prepared nanoparticles are reviewed. These LNPs also underwent characterization to show its presence by a facile method of reducing CPH into nanomaterials. The characterizations include UV-Visible spectrophotometer and Fourier Transform Infrared (FT-IR). The results confirm the presence of these LNPs. Furthermore, the LNPs exhibited fluorescence properties when exposed to UV light. In order to determine the toxicity, the LNPs are tested unto brine shrimps. It proved that these LNPs are nontoxic.

Conclusions: LNPs were successfully synthesized through a simple microwave method. This method is a one-step synthesis and is environmentally friendly. Besides that, the LNPs produced were nontoxic unto the brine shrimp lethality test. Therefore, by using agro-wastes such as CPH, we are able to produce nanomaterials which are fluorescent and has an immense potential to be used as bioimaging tools.

Key words: Luminescent nanoparticles, green synthesis, agricultural wastes, cocoa pod husks

References

1.   Adi-Dako, Ofosua, et al. "Physicochemical and antimicrobial properties of cocoa pod husk pectin intended as a versatile pharmaceutical excipient and nutraceutical." Journal of pharmaceutics 2016 (2016).

2.   Khanahmadi, Soofia, et al. "Cocoa pod husk: A new source of CLEA-lipase for preparation of low-cost biodiesel: An optimized process." Journal of biotechnology 231 (2016): 95-105.