Nanochemistry and biotechnology

Phytosynthesis of irregularly shaped gold nanoparticles: peculiarities, challenges, and future perspectives
Mariychuk R.1, Lisnyak V.V.2
1 Department of Ecology, Faculty of Humanities and Natural Sciences, University of Prešov in Prešov, 17th November Str. 1, 08001, Prešov, Slovakia.
E-mail: ruslan.mariychuk@unipo.sk
2 Faculty of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska Str. 62a, 01601 Kyiv, Ukraine.

The synthesis of metal nanoparticles using plant extracts (phytosynthesis) is one of the green chemistry approaches which deliver ecological, economic, and operational benefits. Plants and their parts, including flowers, leaves, seeds, roots, and bio-wastes, have the potential for the cost- and time-effective, renewable, and eco-friendly synthesis of gold nanoparticles (AuNPs). Another benefit of this approach is the biocompatibility of resulting nanoparticles. The biocompatibility opens the possibility of biomedical applications of a wide diversity of noble metals and their alloys.
In this study, we majorly focused on the recent advances in using the selected plant resources (goldenrod, juniper, peppermint, melissa, etc.), explored for the phytosynthesis of AuNPs. Besides, we will consider the features of their as-developed surfaces, and we take a view on the detection of reactive biomolecules acting as reducing and stabilizing agents. To define the reaction mechanisms, we will shed light on the impact of process parameters and make a quantitative (kinetic) evaluation of the growth of AuNPs. Here, the role of major phenolic compounds, flavonoids, proteins, and terpenoids in the reducing gold ions, and the stabilization of AuNPs, will also be discussed. The effect of reaction parameters, namely, the reaction time, the concentration of gold cations, temperature, pH of the reaction mixture on the forming, size, and morphology of as-developed AuNPs, will be taken into account. We consider these effects in the context of the preparation of irregularly shaped gold nanoparticles at the maximal yields.