Biophysical Insights into the Effects of Alkyl Glucoside Surfactant Structural Characteristics on Antigen Stability under Thermal and Mechanical Stress

The stability of protein antigens during production, storage, and transportation is critical for determining the effectiveness and safety of vaccines. However, protein antigens are susceptible to thermal and mechanical stresses, which can lead to aggregation and decreased immunogenicity. This study utilized alkyl glucosides to analyze the relationship between the structural characteristics of alkyl glucosides and their effects on the biophysical properties of proteins by using antigens, including bovine serum albumin (BSA), human papillomavirus virus-like particles (HPV VLPs), and tetanus toxoid (TT), through comprehensive biophysical analysis. Among the surfactants tested, N-dodecyl-β-d-maltoside (MalC12), with its longer hydrophobic chain and dual-sugar headgroup, was particularly effective in preserving antigen stability. MalC12 formed a dense protective layer through hydrophobic interactions, reducing heat-induced aggregation and maintaining the proteins' secondary structures. Under mechanical stress, MalC12 decreased protein adsorption at interfaces, minimized the risk of protein unfolding, and enhanced hydrophobic interactions with the proteins. In an HPV vaccine model, MalC12 effectively preserved HPV immunogenicity by preventing thermal-induced aggregation. These findings highlight the importance of surfactant characteristics in preventing protein destabilization and offer valuable insights for designing excipients that enhance antigen stability and immunogenicity in vaccine formulations.