Preconcentration of Hemoglobin by a Nickel-Based Metal–Organic Framework (MOF) with Biphenyl Ligands

Abstract

Adsorbents for protein enrichment underline the most important foundations in proteomic application. The construction of tunable metal-organic framework (MOF) through rational selection of metal nodes and organic linkers with designed properties has attracted special interest in the field of protein enrichment. In this work, a nickel-based MOF (NiBPDC) composed of biphenyl-based organic ligand and Ni clusters was prepared which exhibits attractive adsorption efficiency and selectivity for hemoglobin (Hb) by taking advantage of the strong metal affinity and π stacking interaction between Hb and MOF. The adsorption maximum capacity of NiBPDC for Hb is 400.2 mg g−1, and the adsorbed Hb is easily recovered by 0.5% (m/v) sodium dodecyl sulfate achieving a recovery of 98.2%. An enrichment factor up to 79.8 for Hb from an extremely 300:1 mass ratio of a human serum albumin/Hb mixture was achieved. Circular dichroism (CD) spectra reveal that the recovered Hb maintained its original structure following the enrichment. The practicability of NiBPDC is confirmed by selective enrichment of Hb from complex biological samples followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis.