Hydrogen Medicine Materials

Hydrogen medicine materials are defined as a new concept of biomedical materials specifically engineered to overcome critical challenges in hydrogen medicine, including exploration of biological effects and mechanisms of H₂ by in vivo monitoring of H₂ transportation, metabolism and transformation, enhancement of H₂ therapeutic efficacy against various oxidative stress-related diseases by high-efficiency and site-specific delivery and controlled release of H₂, etc. As the smallest and weakly reductive molecule, H₂ exhibits some unique biological characteristics, including high tissue permeability, antioxidative stress (OS), anti-inflammation, antiapoptosis, antisenescence, pro-regeneration/pro-self-repairing, anticancer, antibiofilm, high biocompatibility, and biosafety, holding a high value of biomedical applications. However, the related biological mechanisms are not very clear. Typically, multifaceted biological behaviors of H₂ in varied pathological microenvironments, such as inflammation, cancer, and injured tissue, have not been well elucidated. Moreover, as a therapeutic agent, the pharmacokinetics of H₂, involving absorption, biodistribution, metabolism, and excretion, has to be clarified before clinical application, which needs the development of hydrogen bioprobes to resolve. Based on high biosafety and therapeutic validity of H₂, both hydrogen gas inhalator and hydrogen-rich water generator have been clinically approved for adjuvant therapy of some respiratory and digestive system diseases including chronic obstructive pulmonary disease (COPD), hyperuricemia, hyperlipemia, gastrelcosis and coprostasis, but they hardly realize effective delivery toward remote diseased focuses. Therefore, efficient, site-specific and controlled/sustained H₂-delivering materials with high biosafety urgently need to be developed for improving the outcome of hydrogen therapy. Based on these unique advantages and unsolved key issues in hydrogen medicine, hydrogen medicine materials as an emerging interdisciplinary field have attracted increasing attention in recent years.

In this Account, we present a brief overview of the recent advances of hydrogen medicine materials including hydrogen bioprobes and hydrogen-delivering materials (hydrogen carriers, hydrolytic hydrogen-generating materials, and catalytic hydrogen-generating materials), as well as their typical biomedical applications including targeted inflammation therapy, targeted tumor therapy, and local tissue repair/regeneration. Finally, a forward-looking perspective on hydrogen medicine materials is demonstrated, which attempts to address the current clinical challenges in the field of hydrogen medicine. Especially, the development of small molecular bioprobes for in vivo H₂ detection, the understanding of H₂ pharmacokinetics and potential bioeffects, the exploration of the profound mechanisms underlying multifaceted biological behaviors of H₂, the development of versatile hydrogen-delivering materials for the treatment of various intractable diseases, and the evaluation of potential long-term toxicity risk of both high-dose H₂ and hydrogen-delivering materials are highlighted. This Account is expected to illuminate the way for exploration of hydrogen medicine materials.