Nanoscale photocatalytic hydrogen production system mitigates inflammation by harnessing glycolysis waste

During tissue infection, immune cells undergo glycolysis, generating lactate that intensifies inflammation and contributes to the excessive production of reactive oxygen species (ROS) and pro-inflammatory cytokines. TiO2 serves as a photocatalyst capable of splitting water and producing H2 when activated by UV light. The study proposes the clinical application of TiO2 to combat tissue inflammation, building upon the antioxidative properties of H2. To address the limited tissue penetration depth of UV light, a TiO2-based photocatalytic H2 production system is developed, utilizing upconversion nanoparticles (UCNPs) coated with a double-shell structure of SiO2 and TiO2 (UST NPs). The efficiency of the UST NPs relies on the utilization of tissue-penetrating nearinfrared (NIR) light, which is converted to UV light by the UCNP core. Additionally, the SiO2@TiO2 double-shell enhances light absorbance efficiency and photocatalytic activity. When exposed to NIR light, the UST NPs have the potential to effectively enhance H2 production by utilizing lactate as a sacrificial agent in inflamed tissues, while also facilitating the photocatalytic water splitting process. Consequently, UST NPs + NIR efficiently deplete accumulated lactate in inflamed tissues, reducing inflammation by utilizing the produced H2 to scavenge ROS and pro-inflammatory cytokines. The study explores the innovative application of TiO2-based materials as a photocatalyst, providing fresh perspectives on enhancing H2 production efficiency through the utilization of UCNPs, NIR light, and glycolysis-generated waste (lactate) in inflammation, and examining its relevance in the medical field.