Speaker
Description
Gelatin Methacryloyl (GelMA) attractes considerable research attention as an important structural
component for bioinks.1 The synthesis of GelMA involves the methacrylation of gelatin, wherein methacryl groups are covalently bonded to the amino groups of lysine residues. The degree of methacrylation (DM) is a critical parameter that significantly affects the physicochemical properties of GelMA. For effective bioprinting of organs and tissues, the use of GelMA with a precisely defined DM is essential, as it influences hydrogel stiffness, porosity, swelling behavior, biodegradability, and cellular proliferation. Consequently, there is a need for accessible, cost-effective, precise, and routine methodologies to control and assess the DM of GelMA. This necessity motivated us to develop two novel and complementary methods for determining the DM, both of which can be readily implemented in laboratories equipped with electrophoresis instrument or UV-Vis spectrophotometer.
Currently, the most widely used method for characterizing the degree of methacrylation of GelMA is
nuclear magnetic resonance spectroscopy (NMR).2 Due to the high cost of NMR instrument maintenance, the NMR technique is not routinely available in every laboratory. We are proposing alternative approaches to characterizing GelMA that can be used for routine laboratory analysis. The first proposed method relies on measuring the electrophoretic mobility of GelMA samples, which directly correlates with their degree of methacrylation. This approach requires comparison against reference standards with known DM values and can effectively serve as a classification tool for GelMA products based on their DM. The second method we developed focuses on quality assessment after GelMA fabrication, enabling characterization of pure GelMA through analysis of its absorption spectrum. Although this spectroscopic technique does not require the addition of external reagents such as TNBS,3 the construction of a calibration curve remains necessary to achieve precise quantification.
The precision of both newly developed methods is comparable to the NMR technique, exhibiting
excellent correlation with NMR data (Table 1). The electrophoretic method enables effective
characterization of GelMA even when organic impurities are present. Although this method is somewhat more time-consuming, it can conveniently be substituted with the UV-Vis method for routine applications.
References
1. Yun Piao, Hengze You, Tianpeng Xu et al. Biomedical applications of gelatin methacryloyl hydrogels. Engineered Regeneration 2, 47-56 (2021).
2. Mengxiang Zhu, Yingying Wang, Gaia Ferracci et al. Gelatin methacryloyl and its hydrogels with an exceptional degree of controllability and batch-to-batch consistency. Sci Rep 9, 6863 (2019).
3. A.F.S.A. Habeeb. Determination of free amino groups in proteins by trinitrobenzenesulfonic acid.
Analytical Biochemistry, 328-336 (1966).
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