Márquez, P.G., et al. Cooperative supramolecular integration of QS-21 into polymeric micelles as a tunable nanoadjuvant platform for subunit vaccines. RSC Adv. 2026 May 1, 16(25):22897-22915. PMID: 42080164

This paper is about another adjuvant formulation method with QS-21. This study presents a novel approach to improving the safety and efficacy of QS-21, a potent saponin adjuvant widely used in vaccine formulations, by utilizing cooperative supramolecular integration within amphiphilic PEO–PPO triblock copolymer micelles. Unlike traditional lipid-based systems, the authors demonstrate that QS-21 can participate in architecture-dependent self-assembly into nanoscale micelles, resulting in structures with enhanced dilution stability, controlled membrane activity, and significantly reduced hemolytic activity while preserving immunostimulatory function.

Their in vivo evaluation with a SARS-CoV-2 Spike antigen shows that this nanoadjuvant platform elicits strong systemic and mucosal antibody responses, including neutralizing activity, highlighting its potential for subunit vaccine development. The study highlighted that cooperative self-assembly of QS-21 with PEO–PPO triblock copolymers, particularly P123, results in nanoadjuvant systems with favorable physicochemical and biological properties. Specifically, the architecture-dependent organization modulates QS-21’s interfacial presentation, membrane activity, and in vivo immunogenicity, demonstrating that supramolecular design can enhance immunostimulatory efficacy while mitigating toxicity. The findings suggest that polymer architecture serves as a critical design parameter to optimize nanoadjuvants, providing a promising alternative to lipid-based systems like AS01.