Since most conventional nanozyme are categorized as 'inorganic nanozyme' with considerably high bio-toxicity, this aspect may hinder direct biological application. Also, the toxic properties of these nanozymes may cause environmental damage if they are spread as waste after use. In contrast, all constituent organic materials of the OA nanozyme are referred to as 'practically nontoxic materials' based on their LD50 value (e.g., LD50 > 5,000, unit: mg*kg -1 ). Therefore, OA nanozymes are expected to exhibit minimal toxicity in biological substances containing living organisms. Even though the authors focused on the biosensing application of OA nanozyme, which is an organic compound-based, it was investigated to provide a biotoxicity and biocompatibility profile of OA to provide a further sustainable implementation. The bio-toxicity of OA nanozyme was verified through a conventional cell viability assay incorporated with OA nanozyme incubation for up to 24 hours. The HEK293 cell line, widely used for drug screening and nanoparticle toxicity validation, was used as the target cell line. . A luminance-based viability assay was carried out after 24 hours of incubation, and it was found that OA nanozyme possesses decent cell viabilities (with all concentrations, range of 4X to 0.25X, X= default particle concentration) similar to the 100% survival average as default cell sample which did not treat on nanozyme (Figure ). This profile implies its non-cell toxicity to prove its potential for further biological applications.