Synthetic Porous Melanin

Commonly known as a skin pigment, melanin has a vital role in UV radiation protection, primarily acting as a radical scavenger. However, a lesser known natural property of melanin, observed in some melanized organisms, is its capacity to adsorb toxins, including metals and organic molecules. Inspired by this, we set out to generate a synthetic porous melanin that would pave the way to enhancing the natural adsorbent properties of melanin and melanin-like materials. Here, we developed a method for the synthesis of porous polydopamine-based melanin utilizing a mesoporous silica (MS) nanoparticle template and characterized its physical properties. Through the oxidative polymerization of dopamine, followed by the etching of silica, we generated synthetic porous melanin (SPM) with the highest measured surface area of any known polydopamine-based material. The prepared SPM was effective for the uptake of various gases and organophosphate toxins, with the material exhibiting high selectivity for CO2 over CH4 and high potential for ammonia capture. Given the demonstrated advantages provided by synthetic porous melanin and melanin's role as an adsorbent in nature, we anticipate the discovery of porous analogues in biological systems.

Automated summary

Melanin, commonly known for its role in skin pigment and UV radiation protection, has been found to have the ability to adsorb toxins in some melanized organisms. A synthetic porous melanin (SPM) was successfully developed with the highest measured surface area among polydopamine-based materials, showing effectiveness in absorbing various gases and organophosphate toxins with high selectivity and potential for ammonia capture. The discovery of porous analogues in biological systems is anticipated due to the demonstrated advantages of synthetic porous melanin and melanin's natural adsorbent role.