Rapid synthesis of manganese dioxide nanoparticles for enhanced biocompatibility and theranostic applications.

Manganese dioxide (MnO), lauded for its biocompatibility and distinctive optical and physical characteristics, has become an indispensable material in the biomedical field, showing immense potential in disease detection, treatment, and prevention. Particularly, the ability of MnO nanoparticles to oxidize glutathione (GSH) to its oxidized form has positioned them as pivotal players in GSH sensing. However, conventional preparation methods, whether top-down or bottom-up, often result in nanoparticles that require multi-step processing and modification to achieve good dispersion in physiological conditions, which is both time-consuming and complex. To address this, a rapid and efficient method was developed for producing well-dispersed and stable MnO nanoparticles using tannic acid to reduce potassium permanganate. The polyphenolic structure of tannic acid not only facilitates the reduction process but also enhances the dispersibility of the nanoparticles in biological environments. In addition, PEG could improve the stability of MnO nanoparticles and also reduce their size. Moreover, we demonstrate the application of these nanoparticles in a colorimetric assay for GSH detection, leveraging their ability to react with GSH to produce Mn. Furthermore, these nanoparticles were utilized in a colorimetric assay for GSH detection, harnessing their reactivity with GSH to generate Mn. Beyond this, the MnO nanoparticles exhibit potential for the loading of a spectrum of molecules, including small molecules, peptides, DNA, RNA, and proteins, through electrostatic interactions, π-π stacking, and the inherent reactivity of polyphenols. This groundbreaking strategy heralds a new era for MnO in the realm of theranostic agent delivery, offering a promising avenue for enhancing diagnostic accuracy and therapeutic efficacy in biomedical applications.