# Progress in the Expression, Purification, and Characterization of Recombinant Collagen

## TL;DR

This review summarizes advances in making and testing recombinant collagen, highlighting its benefits and potential uses in medicine and cosmetics.

## Contribution

The paper provides a comprehensive overview of expression systems, purification methods, and characterization techniques for recombinant collagen.

## Key findings

- Recombinant collagen offers advantages like high bioactivity and low immunogenicity, suitable for biomaterials and skincare.
- Various expression systems like E. coli and Pichia pastoris are compared for efficiency and cost-effectiveness.
- Purification methods such as affinity and ion-exchange chromatography are analyzed for their effectiveness.

## Abstract

Synthesized by expressing natural collagen sequences in specific hosts, recombinant collagen exhibits multiple advantages, encompassing a higher content of bioactive domains, enhanced antioxidant activity, the absence of viral pathogens, favorable hydrophilicity, reproducible production, and low immunogenicity. Consequently, it has found extensive use in applications ranging from biomaterials and pharmaceuticals to skincare. This review systematically explores various expression systems for recombinant collagen, including those utilizing Escherichia coli, Pichia pastoris, plants, insect baculovirus, and mammalian cells. It provides a detailed comparison of their differences and commonalities in terms of production efficiency, post-translational modification capability, and cost-effectiveness. Key separation and purification techniques for recombinant collage-notably precipitation, affinity chromatography, ion-exchange chromatography, and gel filtration chromatography are further introduced, with an in-depth analysis of the applicable scenarios and purification outcomes for each method. Finally, the review comprehensively summarizes the characterization methods for both the physicochemical properties and biological functions of recombinant collagen. For physicochemical properties, techniques covered include scanning electron microscopy, micro-differential thermal analysis, circular dichroism spectroscopy, SDS-PAGE, mass spectrometry, and Fourier-transform infrared spectroscopy. For biological functions, the focus is on its roles and the corresponding assessment methods in processes such as cell proliferation, migration, adhesion, and wound healing. Building upon this comprehensive overview, current challenges facing recombinant collagen are identified, and future directions are proposed, emphasizing the need to reduce R&D costs, refine testing methods for cosmetic products, and improve safety evaluation protocols to advance the field.