Characterization of novel mixed-mode protein adsorbents fabricated from benzoyl-modified polyethyleneimine-grafted Sepharose

Transforming waste into valuables: Preparation and evaluation of dual-ligand hydrophobic charge-induction chromatography using two poor performing ligands

In conventional chromatographic ligand screening, underperforming ligands are often dismissed. However, this practice may inadvertently overlook potential opportunities. This study aims to investigate whether these underperforming ligands can be repurposed as valuable assets. Hydrophobic charge-induction chromatography (HCIC) is chosen as the validation target for its potential as an innovative chromatographic mode. A novel dual-ligand approach is employed, combining two suboptimal ligands (5-Aminobenzimidazole and Tryptamine) to explore enhanced performance and optimization prospects. Various dual-ligand HCIC resins with different ligand densities were synthesized by adjusting the ligand ratio and concentration. The resins were characterized to assess appearance, functional groups, and pore features using SEM, FTIR, and ISEC techniques. Performance assessments were conducted using single-ligand mode resins as controls, evaluating the selectivity against human immunoglobulin G and human serum albumin. Static adsorption experiments were performed to understand pH and salt influence on adsorption. Breakthrough experiments were conducted to assess dynamic adsorption capacity of the novel resin. Finally, chromatographic separation using human serum was performed to evaluate the purity and yield of the resin. Results indicated that the dual-ligand HCIC resin designed for human antibodies demonstrates exceptional selectivity, surpassing not only single ligand states but also outperforming certain high-performing ligand types, particularly under specific salt and pH conditions. Ultimately, a high yield of 83.9 % and purity of 96.7 % were achieved in the separation of hIgG from human serum with the dual-ligand HCIC, significantly superior to the single-ligand resins. In conclusion, through rational design and proper operational conditions, the dual-ligand mode can revitalize underutilized ligands, potentially introducing novel and promising chromatographic modes.

Etherified pullulan-polyethylenimine based nanoscaffolds improved chemosensitivity of erlotinib on hypoxic cancer cells

The current research endeavor aimed to accomplish hypoxia-responsive polyethyleneimine-conjugated carboxymethyl pullulan-based co-polymer (CMP-HA-NI-PEI-NBA) bearing nitroaromatic subunits to efficiently deliver erlotinib (ERL) to reverse its hypoxia-induced resistance in cancer cells. As compared to a control co-polymer (CMP-HA-MI-PEI-BA) devoid of hypoxia-sensitive moieties, this scaffold demonstrated a hypochromic shift in the UV spectra and rapid dismantling of its self-assembled architecture upon exposure to simulated hypoxic condition. The hypoxia-responsive co-polymer encapsulated ERL with desirable loading capacity (DEE, 63.05 ± 2.59%), causing attenuated drug crystallinity. The drug release rate of the scaffold under reducing condition was faster relative to that of non-reducing environment. Their cellular uptake occurred through an energy-dependent endocytic process, which could exploit its caveolae/lipid raft-mediated internalization pathway. The ERL-loaded scaffolds more efficiently induced apoptosis and suppressed the proliferation of drug-resistant hypoxic HeLa cells than the pristine ERL. Hence, this study presented a promising drug delivery nanoplatform to overcome hypoxia-evoked ERL resistance.

Recent advances in protein chromatography with polymer-grafted media

The strategy of using polymer-grafted media is effective to create protein chromatography of high capacity and uptake rate, giving rise to an excellent performance in high-throughput protein separation due to its high dynamic binding capacity. Taking the scientific development and technological innovation of protein chromatography as the objective, this review is devoted to an overview of polymer-grafted media reported in the last five years, including their fabrication routes, protein adsorption and chromatography, mechanisms behind the adsorption behaviors, limitations of polymer-grafted media and chromatographic operation strategies. Particular emphasis is placed on the elaboration and discussion on the behaviors of ion-exchange chromatography (IEC) with polymer-grafted media because IEC is the most suitable chromatographic mode for this kind of media. Recent advances in both the theoretical and experimental investigations on polymer-grafted media are discussed by focusing on their implications to the rational design of novel chromatographic media and mobile phase conditions for the development of high-performance protein chromatography. It is concluded that polymer-grafted media are suitable for development of IEC and mixed-mode chromatography with charged and low hydrophobic ligands, but not for hydrophobic interaction chromatography with high hydrophobic ligands and affinity chromatography with ligands that have single binding site on the protein.

Polyethyleneimine-facilitated high-capacity boronate affinity membrane and its application for the adsorption and enrichment of cis-diol-containing molecules

High capacity boronate affinity membranes were prepared for the first time, the membranes possess good selectivity, faster adsorption and desorption speed towards cis-diol-containing molecules.