Rapid synthesis of gold nanoparticles with Cissus quadrangularis extract using microwave irradiation

The present study focuses on the rapid synthesis of gold nanoparticles (AuNP) using the aqueous extract of Cissus quadrangularis (CQE) by microwave irradiation. The UV–Visible spectroscopy of the solution obtained from reduction of hydrogen tetrachloroaurate (HAuCl4) by CQE revealed a sharp surface plasmon resonance (SPR) peak at 530 nm confirming the presence of AuNP. The formation of AuNP was optimal at a pH of 9. The AuNP was characterised by FT-IR, SEM, HR-TEM, SAED, XRD, TGA, DLS and Zeta potential measurements. The results indicated that microwave assisted synthesis produced well dispersed, small sized, uniform nanoparticles when compared to conventional room temperature synthesis. The spherical nanoparticle had an average size of 12.0 ± 3.2 nm as revealed through TEM. The crystalline nature of AuNP was confirmed through HR-TEM, SAED and XRD. The FT-IR and TGA data revealed the presence of the CQE components on the surface of the AuNP particles which serve as the capping agent. Upon incubation, the particles did not lyse the red blood corpuscles (RBCs) indicating that they are biocompatible. A possible mechanism for the formation of AuNP in the presence of CQE is proposed.

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► Synthesis of uniform sized AuNP using microwave irradiation.
► Formation of stable AuNP is concentration and pH dependent.
► Crystallinity revealed through XRD, HR-TEM and SAED.
► Average particle size was 12.0 ± 3.2 nm.