Boheng Liu

The design and optimization of immobilized metal affinity chromatography (IMAC) media are crucial to enhancing the purification efficiency of recombinant proteins. In this study, the agarose-based microspheres are prepared by using a three-factorial Box–Behnken design followed by NTA-Ni²⁺ agarose-based microspheres (ABM) preparation by the “one-step” crosslinking of epichlorohydrin (ECH)–nitrilotriacetic acid (NTA) to efficiently couple the NTA ligand to the surface of the matrix. After preparation, various sophisticated techniques, including SEM, AFM, DSC, FTIR, and SDS-PAGE, were used to analyze the morphological structure, thermal stability, and chemical composition of NTA-Ni²⁺ ABM. The optimal conditions are identified as an emulsifier PP concentration of 8.12 wt%, a stirring speed of 1624.46 rpm, and an oil-phase temperature of 53.86 °C, giving a span value (Y) of 0.50684. SEM, AFM, DSC, and FTIR results showed that the fabricated NTA-Ni²⁺ ABM were structurally stable and had a uniform cross-linking network for up to 8 h of coupling reaction time. The performance results showed that the beads had a high binding capacity for His-tagged proteins (15.2 ± 0.8 mg/mL), and SDS-PAGE results demonstrated the efficient purification ability for target proteins. These findings provide the theoretical basis and a practical solution for the rational design and application of IMAC medium.

Mussel foot protein is a bioadhesive protein with potential biomedical applications, but its limited solubility and poor biological stability hinder its widespread use. In this study, highly soluble mussel foot protein (HMFP) was successfully extracted using a stepwise selective enzymatic digestion method, with a molecular weight in the range of 11–17 kDa. Furthermore, a dual-functional polyethylene glycol (PEG) derivative of HMFP, designated HMFP-PEG, was synthesized. FTIR analysis confirmed the successful modification of HMFP with PEG, while TGA analysis and SEM observations demonstrated that PEG modification significantly enhanced the stability of the protein. Both HMFP and HMFP-PEG effectively scavenged free radicals, enhanced antioxidant enzyme activity, and reduced MDA levels. Additionally, they activated the PI3K/Akt and Nrf2/HO-1 signaling pathways, inhibiting H₂O₂-induced cell apoptosis. Notably, HMFP-PEG exhibited superior antioxidant and cell-protective effects compared to HMFP, suggesting that PEG modification improves the functional stability of the protein. This study provides theoretical support for the potential application of HMFP in the biomedical and tissue engineering fields.