Understanding the In Situ Mechanistic Control of Plant‐Derived Carbon Quantum Dots on the Synthesis of Gold Nanoparticles

• Published in: ChemistrySelect (Weinheim) 2019-12, Vol.4 (46), p.13677-13688
• Main Authors: Shukla, Devyani, Bose, Subhaya, Choudhury, Smarajit P., K. Sharma, Vinay, Das, Megha, Sabbarwal, Shivesh, Yadav, Sanjeev K., Kumar, Manoj, Parmar, Avanish S.
• Format: Article
• Language: English
• Subjects: absorption spectroscopy; Arjuna terminalia; carbon quantum dots; collagen; gold nanoparticles; β-mercaptoethanol
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.201903634

Arjuna terminalia‐ derived Carbon Quantum Dots synthesized by hydrothermal method are utilized to investigate the effect of their reaction parameters on the synthesis and growth of gold nanoparticles. In this study, carbon dots are synthesized at two temperatures (160 °C and 200 °C) and two solvents (water and ethanol) to investigate the effect of four variants on the formation of non‐cytotoxic gold nanoparticles. They are extensively characterized to understand their different physical and chemical properties. Gold nanoparticles synthesized using ethanol based carbon dots show greater stability. Addition of Type‐I collagen stabilizes the gold nanoparticles to form gold nanoparticle‐coated collagen fibrils. Further, β‐mercaptoethanol initiates a spontaneous precipitation and sedimentation of visible gold micelles similar to “snowing”. This work may help in future to understand the reduction of chloroauric acid using bio‐derived plant extracts, microbial consortium and very recently, carbon quantum dots, for specific tailoring of gold nanoparticles for biomedical, surface‐enhanced Raman spectroscopy and theranostics applications. The mechanistic control of carbon quantum dots on the growth and morphological inclination of gold nanoparticles has been studied in detail. Type‐1 collagen increases the stability of the less‐stable gold nanoparticles synthesized using water based carbon dots. Addition of β‐mercaptoethanol into the salt‐containing gold nanoparticle solution causes spontaneous “snowing” of the gold nanoparticles. The nanoparticles are highly biocompatible and the role of epoxy group on the carbon dot surface in the reduction and stabilisation of gold nanoparticles has been hypothesized.