Investigation of bi-enzymatic reactor based on hybrid monolith with nanoparticles embedded and its proteolytic characteristics

Efficient and rapid digestion of proteins with a dual-enzyme microreactor featuring 3-D pores formed by dopamine/polyethyleneimine/acrylamide-coated KIT-6 molecular sieve

The microreactor with two types of immobilized enzymes, exhibiting excellent orthogonal performance, represents an effective approach to counteract the reduced digestion efficiency resulting from the absence of a single enzyme cleavage site, thereby impacting protein identification. In this study, we developed a hydrophilic dual-enzyme microreactor characterized by rapid mass transfer and superior enzymatic activity. Initially, we selected KIT-6 molecular sieve as the carrier for the dual-IMER due to its three-dimensional network pore structure. Modification involved co-deposition of polyethyleneimine (PEI) and acrylamide (AM) as amine donors, along with dopamine to enhance material hydrophilicity. Remaining amino and double bond functional groups facilitated stepwise immobilization of trypsin and Glu-C. Digestion times for bovine serum albumin (BSA) and bovine hemoglobin (BHb) on the dual-IMER were significantly reduced compared to solution-based digestion (1 min vs. 36 h), resulting in improved sequence coverage (91.30% vs. 82.7% for BSA; 90.24% vs. 89.20% for BHb). Additionally, the dual-IMER demonstrated excellent durability, retaining 96.08% relative activity after 29 reuse cycles. Enhanced protein digestion efficiency can be attributed to several factors: (1) KIT-6's large specific surface area, enabling higher enzyme loading capacity; (2) Its three-dimensional network pore structure, facilitating faster mass transfer and substance diffusion; (3) Orthogonality of trypsin and Glu-C enzyme cleavage sites; (4) The spatial effect introduced by the chain structure of PEI and glutaraldehyde's spacing arm, reducing spatial hindrance and enhancing enzyme-substrate interactions; (5) Mild and stable enzyme immobilization. The KIT-6-based dual-IMER offers a promising technical tool for protein digestion, while the PDA/PEI/AM-KIT-6 platform holds potential for immobilizing other proteins or active substances.

Self-assembly synthes is of trypsin-immobilized monolithic microreactor for fast and efficient proteolysis

Fast and highly efficient digestion of proteins is essential for high-throughput proteomic analysis. Herein, a facile approach was developed for self-assembly preparation of trypsin-immobilized capillary monolithic column and its application as an immobilized enzyme microreactor (IMER) for fast and highly efficient proteolysis was described. The performance of the trypsin-immobilized monolithic enzyme microreactor was evaluated by in-situ digestion of model proteins. The results showed that the trypsin-immobilized monolithic enzyme microreactor had much higher tryptic digestion efficiency than the free trypsin in solution, where the coverage of peptide sequences by mass spectrometry (MS)-based analysis could bear comparison with the free one, while the digestion time was dramatically shortened from 12 h to 16 s. Furthermore, the trypsin-immobilized monolithic enzyme microreactor also exhibited good practicability to complex human serum sample, in which the total of 45 peptides from human serum albumin (HSA) matched with sequence coverage of 75% were precisely identified. The successful application demonstrated the promising potential of the trypsin-immobilized capillary monolithic column as the IMER in high-throughput proteomic analysis.

Novel approaches for biomolecule immobilization in microscale systems

This manuscript reviews novel approaches applied for biomolecule immobilization in microscale systems.

Monolith columns for liquid chromatographic separations of intact proteins: A review of recent advances and applications

In this article we survey 256 references (with an emphasis on the papers published in the past decade) on monolithic columns for intact protein separation. Protein enrichment and purification are included in the broadly defined separation. After a brief introduction, we describe the types of monolithic columns and modes of chromatographic separations employed for protein separations. While the majority of the work is still in the research and development phase, papers have been published toward utilizing monolithic columns for practical applications. We survey these papers as well in this review. Characteristics of selected methods along with their pros and cons will also be discussed.