Plug-and-play safe-by-design production of metal-doped tellurium nanoparticles with safer antimicrobial activities

Safe-by-design principles, such as optimum balance of material function and safety, have received much recent attention. On-demand production is also receiving great interest in the realization of nanotechnologies that meet unpredictable demands of reconfiguration and modification to maximize the efficacy of materials processing. Antimicrobial nanomaterials are representative subjects of these approaches, because they require built-to-order configurations with safe-by-design principles for practical applications. However, few studies have achieved biosafety with original material function using economically feasible production platforms. In this regard, we developed a safe-by-design plug-and-play approach for continuous gas flow production of silver (or copper)-doped tellurium (Ag- or Cu-Te) nanoparticles with safer antimicrobial activity. Using this approach, we achieved precise modulation of dopant contents (5-8% atomic Ag and Cu) in nanoparticles without using batch hydrothermal chemistry. We also suggest the use of ratios between biocompatibility and antimicrobial activity as safety indices (SIs) for evaluations of nanoparticle applications. Approximately 6% atomic Ag in Ag-Te particles exhibited an optimal SI and significantly reduced the minimum inhibitory concentration of individual Te nanoparticles.