Biosynthesis of metallic nanoparticles

In search of environmentally friendly alternatives for nanoparticle production

Nanoparticles are part of the reality of our lives - they are everywhere. We absorb them through breathing, food and skin. A distinction is made between nanoparticles that are intentionally synthesized and deliberately added to products and those that are unintentionally created by chemical-physical processes, as well as nanostructures that occur naturally. The research work of Lucia Colleselli, a researcher in the area of Food Sciences & Biotechnology at MCI, focuses on the development of sustainable, green, biologically based synthesis methods of nanoscale materials using suitable microorganisms. The aim is to produce reproducible metallic nanoparticles (NP) with defined character and controlled size tuning.

Metallic nanoparticles (NPs) are compounds in the range of 1-100 nm (1 nm = 1 nanometer = 10^-9 meters or one billionth of a meter). Nanoparticles exhibit unique properties depending on their size, shape and structure. Due to their underlying morphological properties, specific functional NPs find a wide range of applications in the pharmaceutical, food, and cosmetics industries, as well as in agriculture, medicine, and environmental engineering. Conventional production of nanomaterials is based on chemical and physical processes that often have negative effects on humans and the environment and therefore severely limit biomedical applications. Therefore, environmentally friendly, sustainable processes for NP production are required.

A variety of microorganisms possess the ability to reduce metallic cations and form nanoscale particles. Biotechnologically generated metallic nanomaterials offer enormous potential for expanding the range of applications due to their special biological particle structures. The processes are resource efficient, energy efficient, and cost efficient and provide an environmentally friendly alternative for nanoparticle production. Meeting the increasing demand for biosynthetic metallic NPs for cross-industry applications is a major challenge for the future.

In the research proposal of Lucia Colleselli, the focus is on the elaboration of the question: How to synthesize metallic NPs with defined morphology and specific features microbially mediated. First, microorganisms such as fungi, microalgae and bacteria are screened for their suitability to biogenically generate metallic nanomaterials. Initial experiments have successfully identified biologically generated silver nanoparticles using yeasts. The results of recent preliminary experiments on NP production by microalgae also indicate their high potential for metal ion reduction.

Based on the successful performance of these preliminary experiments with yeasts and microalgae, synthesis methods that can be adapted to different microorganism species will be explored. Since the specific properties of NPs strongly depend on that of the particle size, future experiments will aim to obtain different particle size regimes by varying the synthesis parameters and to achieve the biosynthesis of NPs from a selection of metals such as silver (Ag), gold (Au), copper (Cu) or copper oxide by different microbial species. In addition, the discovery of microbial macromolecules involved in biosynthesis will be pursued.

This research is funded by the State of Tyrol within the K-Regio project SUPREMEbyNANO.