The OA nanozyme was fabricated using a customized methodology, modified from previous references . Iron sulfate heptahydrate powder solutions were prepared using deionized water as a solvent at concentrations up to 1mg mL -1 . Polyethylene glycol (PEG) powder was dissolved in the deionized water at a 10X concentration and then diluted to the target concentration (1X is equivalent to approximately 1mg mL -1 ,). These two solutions reacted homogeneously under stirring conditions at room temperature around 25°C (PEG solution volume = 75% volume of iron sulfate). Alanine solution (approximately 1mg mL 1 ) was added dropwise under continuous stirring. The mixture was incubated for up to two hours at 4°C to stabilize the particles. Particles (OA nanozyme) were collected through centrifuge-down steps for 10 minutes (max 4000 rpm).