pH-controlled reversible sol-gel inversion by cerous phosphate nanofibers for hemostasis

Developing biomimetic soft materials that display stimuli responsiveness using solely inorganic materials has been regarded as a challenge owing to that such materials’ properties typically vary from those of living organisms. Traditionally, biomimetic soft materials have been developed using organic materials or inorganic materials modified with organic small molecules. In this study, we prepared cerium phosphate nanofibers (CePO₄ NFs) by using inorganic agents only without further modification. The CePO₄ NFs demonstrate sol-gel switching properties in response to pH value, allowing them to form a gel under high hydroxide ion (OH⁻) concentrations and turn back into sol under low OH⁻ concentrations. The formation of gel could be ascribed to the physical cross-linking of the nanofibers induced by the attractive electrostatic force of OH⁻ and surface Ce³⁺. As a result, CePO₄ NFs are able to form a gel when in contact with blood of high pH value for hemostasis. This specific clotting mechanism makes them better candidates for hemostasis of heavy bleeding.

Graphical abstract