fragile drugs, broken cold chains

Problem statement

Biological therapeutics — cell therapies, vaccines, blood products, tissue grafts, mRNA drugs — require continuous cold chain storage from manufacture to administration. PAHO/WHO cold chain guidance stores freeze-sensitive vaccines at 2–8°C and vaccines made with viral and/or lyophilized strains at −15 to −25°C; mRNA vaccines have required ultracold storage, a range the vaccine-formulation literature describes as "ultracold temperatures (−80°C to −20°C)" that pose "a significant barrier to rapid deployment and equitable distribution, especially in resource-limited regions with inadequate refrigeration infrastructure"; cell therapies require cryopreservation. Cold chain infrastructure is expensive, energy-intensive, fragile, and unavailable in many low-resource settings — ARPA-H, launching its BioStabilization Systems (BoSS) program to eliminate it, states that a dose can be "ruined from just one power outage, one shipping delay, or one freezer failure." The viability window for cell products outside the cold chain is short: a clinical CAR-T group measured the stability of fresh, non-cryopreserved CAR T cells stored at 5 ± 3°C across three infusion products and determined it to be four hours, concluding that "cryopreservation is a necessity for the production at centralized sites." No technology exists to stabilize living cells or complex biologics at room temperature while maintaining their function; the mechanisms that protect organisms from desiccation and heat stress (trehalose accumulation, heat shock proteins, late embryogenesis abundant proteins) have been partly identified but not reproducibly transferred into therapeutic products.

Why this matters

ARPA-H puts the recurring cost of the cold chain at "tens of billions of dollars in cost every year," and frames room-temperature biologics as a "200-degree leap" in preservation temperature. The infrastructure gap is concentrated where the need is greatest: Gavi reported in 2018 that around one fifth of immunisation facilities in the world's poorest countries lack the equipment needed to hold vaccines at the right temperature, that much of the equipment that is installed "functions poorly or doesn't work at all," and that between 37–50% of all monitored vaccines stored in lower-income countries had at some point been held at temperatures deemed "too cold" — freezing damage, not only heat. Working around the cold chain demonstrably improves coverage: a Journal of Global Health scoping review of controlled temperature chain (CTC) delivery found interventions such as a 27% median increase in hepatitis B birth-dose coverage in intervention districts, but only two vaccines — MenAfriVac and Gardasil — are licensed for CTC use, short of WHO's goal of licensing additional thermostable vaccines by 2020. COVID-19 exposed the same bottleneck acutely for ultracold mRNA vaccines. Cell therapies, which must be manufactured and administered within a tight viability window, are limited to major medical centers: for cryopreserved commercial products the average time from leukapheresis to infusion is typically 30 to 45 days including shipment, manufacturing, and QC, against roughly 6–10 days for on-site fresh production. Room-temperature stabilization would widen access to biologics and reduce waste, cost, and environmental impact.

What’s been tried and why it hasn’t worked

Lyophilization (freeze-drying) works for some protein-based biologics and vaccines but destroys living cells — the ice crystal formation during freezing ruptures cell membranes. Adding cryoprotectants (DMSO, glycerol, trehalose) can protect cells during freezing but requires rapid thawing at the point of use and does not extend shelf life at room temperature. Anhydrobiosis research (studying organisms like tardigrades and brine shrimp that survive complete desiccation) has identified protective molecules, and the transfer into human cells was demonstrated a quarter-century ago — Guo et al. engineered trehalose expression in human cells and showed it confers desiccation tolerance (Nature Biotechnology, 2000) — yet no therapeutic cell product uses the approach today, which is the measure of how hard the gap between tolerance and clinical-grade function has proven. Encapsulation in alginate or other hydrogels can protect cells for hours but not the weeks to months needed for storage and distribution. Nucleic-acid formulations are further along than living cells: lyophilized self-replicating RNA vaccines with 10% sucrose have been reported stable for "at least 1 week at 25°C" and "at least 6 months at 2–8°C" while retaining immunogenicity (Gulati et al., 2024) — a result that shows the drying route works for the molecule but leaves the cell problem untouched.

What would unlock progress

Technologies that enable room-temperature storage of living cells for weeks to months while maintaining viability and function would transform biologics access. Approaches include: (1) engineering mammalian cells to express natural desiccation tolerance pathways (trehalose synthesis, LEA protein production) that enable them to survive dehydration; (2) novel encapsulation matrices that physically immobilize cells in a glass-like state at room temperature while maintaining membrane integrity; (3) synthetic analogs of natural cryoprotectants that can be loaded into cells at non-toxic concentrations. What counts as success is being defined right now: ARPA-H's BoSS program rules that "solutions that require cold storage of biologic medicines are considered out of scope," scores awardees on cellular viability, apoptosis, metabolic activity, production speed, and shelf-life stability at ambient room temperature (the numeric thresholds sit in the program's Innovative Solution Opening rather than on the public page), and caps the bioprocessing system's suggested retail price at $200,000 so that the result is affordable at the point of care.

Entry points for student teams

A student team could engineer a mammalian cell line to express trehalose synthase (from E. coli or tardigrade orthologs) and measure whether intracellular trehalose accumulation improves survival after controlled desiccation and rehydration. A materials-focused team could screen different hydrogel and sugar-glass encapsulation matrices for their ability to maintain red blood cell integrity at room temperature over days to weeks. Relevant disciplines: biomedical engineering, cell biology, materials science, chemical engineering.