Preparation and Application of Low-Cost, Large-Scale, Micrometer-Sized Hemoglobin Crystals

During protein crystallization, several solvent channels can form pore structures of different sizes, which can accommodate small molecules, enabling numerous functional applications. However, the large-scale synthesis of uniformly sized protein crystals remains a considerable challenge. Herein, millimeter-, micrometer-, and nanometer-sized hemoglobin crystals were synthesized from waste blood by using various processes. Furthermore, we progressively expanded the preparation system of micrometer-sized hemoglobin crystals, successfully obtaining numerous uniform-sized hemoglobin crystals in a 1 L crystallization system. Subsequently, stable cross-linked hemoglobin crystals (CLHCs), which are suitable for industrial applications, were synthesized via glutaraldehyde-induced cross-linking. Furthermore, the crystallization conditions were continuously optimized, ultimately increasing the CLHC yield to 97 g/L of blood. Moreover, cost estimations revealed that the production cost for 1 kg of CLHCs was only 25.25 CNY (3.70 USD). Finally, the practical application potential of CLHCs in dye adsorption and precious metal recovery was estimated.