The impact of different lyophilization regimes on the protein composition of human cord blood serum

Abstract

Background: Modern medicine is confronted with the challenge of minimizing the side effects of drug treatment of serious diseases, including oncological pathologies. One of the most perspective concepts is the use of cord blood serum as a source of regenerative components to support the patient's health. The serum contains a variety of growth factors, cytokines and immunosuppressive cells that promote tissue repair and regulation of the immune response. An important goal is to preserve the biological activity of cord blood serum protein fractions during long-term preservation. Lyophilization is considered one of the most effective methods of stabilizing biological substances. However, the optimal temperature regime for the preservation of cord blood proteins during lyophilization requires further investigation. Objectives: To evaluate the effect of different lyophilization regimes on the composition and stability of cord blood serum proteins. Materials and methods: Cord blood serum was examined after freezing to -20°C and lyophilization with previous cooling to -20°C and -80°C. The total protein content was calculated using a standardized determination kit, and the remaining dry mass was weighed on an analytical balance. The protein composition was examined by spectrofluorimetry and polyacrylamide gel electrophoresis. The residues of aromatic amino acids (tyrosine-tryptophan, tryptophan) were analyzed by spectrofluorimetry. The peaks in the protein profiles of the analytical samples were electrophoretically examined and the preservation of the biomaterial was compared. Results: It has been shown that freezing and lyophilization at -80°C provide high stability of protein fractions without significant loss of total protein or its structural changes. On the contrary, lyophilization at -20°C was accompanied by a significant decrease in the total amount of protein and protein fractions, changes in protein structure, indicating aggregation, denaturation, and degradation of protein molecules. The densitogram of lyophilized cord blood serum when cooled to -80°C was significantly close to the result of the frozen sample, while the analysis of the peaks of lyophilized serum cooled to -20°C showed a significant decrease in parameters. Conclusions: Lyophilization of human cord blood serum with preliminary cooling at -80°C allows preserving the protein concentration, the number of fractions and the structure of proteins according to electrophoresis and spectrofluorimetry. Lyophilization of cord blood serum with preliminary cooling at -20°C significantly reduces the protein concentration, the number of fractions and changes the structure of proteins compared to frozen serum.