Autonomous Abiotic Thermal Protectant for Immunoglobulin G: Reducing the Need for Cold Chain Storage

Antibodies are vital biologic therapeutics, but their impact is limited by thermal instability. This requires maintaining a cold chain, from the point of manufacture to the point of use. We report an approach that could reduce the need for a cold chain. We present a thermal protectant (TP) for immunoglobulin G (IgG) that mimics the behavior of the heat shock protein HSP60. This hydrogel copolymer nanoparticle shows minimal affinity for IgG at or below 25 °C. As temperatures rise and approach the proteins melting temperature (T_m), the TP undergoes an autonomous phase transition (∼27 °C), above which the TP shows high affinity for IgG sequestering and stabilizing IgG at temperatures far above T_m. As temperatures return to RT, the TP reverts to its water-swollen state, allowing any metastable proteins time to refold to their native state before being released. The optimized TP has very low IgG molar capacity, effectively isolating and preventing aggregation at elevated temperatures.