Philip Michael Williams

Space missions require liquid drug formulations that remain physically stable and exhibit predictable release under launch, microgravity, and handling stresses. This study examined melatonin‑loaded nanoemulsions flown on the MAPHEUS‑15 sounding rocket, comparing an uncoated nanoemulsion (MN) with a chitosan‑coated nanoemulsion (CCN). Droplet size, polydispersity index (PDI), and zeta potential were measured at Day 0 and after spaceflight, ground vibration testing, matched ground controls, and laboratory storage. Melatonin release was quantified by dynamic dialysis and interpreted using a compartmental mass‐transfer model. Melatonin‑loaded nanoemulsion (MN) showed a modest, systematic increase in droplet size under all post‑experiment conditions, with unchanged PDI and zeta potential, consistent with time‑dependent coalescence and Ostwald ripening rather than a specific microgravity effect. CCN maintained essentially unchanged droplet size, PDI, and zeta potential, indicating interfacial steric stabilization by chitosan. For MN, ageing and sounding‑rocket exposure increased the apparent fraction of melatonin available to the aqueous phase, but normalized release profiles overlapped when scaled to the fitted maximum releasable fraction, suggesting unchanged intrinsic release kinetics. In CCN, both the accessible fraction and the release profile were preserved. Overall, chitosan coating enhanced dimensional and release stability, supporting interfacial polymer coatings as a strategy for robust liquid pharmaceutical formulations for future space medicine.

Centralised cell-based biomanufacturing severely limits applicability in low-resource and extreme environments, where a largely untreated human population is present. Cell-free protein synthesis (CFPS) can surpass many of these limitations, due to its flexibility and low maintenance. After initial optimisation for high-level expression, we conceptualised CFPS platforms composed of lyophilised pellets and cellulose stacks for ease of storage and distribution. The latter platform consisted of lyophilised components on cellulose discs, which were layered and rehydrated to kickstart protein synthesis. Such paper-encompassed reactions were capable of robust expression, where the system can be modulated by simply changing the DNA layer. Using an initial screening design followed by a minimalistic design of experiments approach, we were able to improve the shelf life of lyophilised CFPS at room temperature from <1 week to 100% preservation at month 1. We anticipate that our strategy will enable quicker and more efficient stability optimisation for sustainable applications in all environments.

Centralised cell-based biomanufacturing severely limits applicability in low-resource and extreme environments, where a largely untreated human population are present. Cell-free protein synthesis (CFPS) can surpass many of these limitations, due to its flexibility and low maintenance. After initial optimisation for high-level expression, we conceptualised CFPS platforms composed of lyophilised pellets and cellulose stacks for ease-of-storage and distribution. The latter platform consisted of lyophilised components on cellulose discs, which were layered and rehydrated to kickstart protein synthesis. Such paper-encompassed reactions were capable of robust expression, where the system can be modulated by simply changing the DNA layer. Using an initial screening design followed by a minimalistic design of experiments approach, we were able to improve the shelf-life of lyophilised CFPS at room temperature from < 1 week to 100% preservation at month 1. We anticipate that our strategy will enable quicker and more efficient stability optimisation for sustainable applications in all environments.

Spaceflight presents significant challenges to the physiological state of living organisms. This can be due to the microgravity environment experienced during long-term space missions, resulting in alterations in muscle structure and function, such as atrophy. However, a comprehensive understanding of the adaptive mechanisms of biological systems is required to devise potential solutions and therapeutic approaches for adapting to spaceflight conditions. This review examines the current understanding of the challenges posed by spaceflight on physiological changes, alterations in metabolism, dysregulation of pathways and the suitability and advantages of using the model organism Caenorhabditis elegans nematodes to study the effects of spaceflight. Research has shown that changes in the gene and protein composition of nematodes significantly occur across various larval stages and rearing environments, including both microgravity and Earth gravity settings, often mirroring changes observed in astronauts. Additionally, the review explores significant insights into the fundamental metabolic changes associated with muscle atrophy and growth, which could lead to the development of diagnostic biomarkers and innovative techniques to prevent and counteract muscle atrophy. These insights not only advance our understanding of microgravity-induced muscle atrophy but also lay the groundwork for the development of targeted interventions to mitigate its effects in the future.

In extreme environments people will have different needs for medicine(s). It is important, therefore, to know how medicine efficacy will be impacted by the environment. Ibuprofen is very widely used in tablet formulation in temperate climates on Earth. Via the first companion experiment inside the International Space Station (ISS) and outside ISS at the Multipurpose International Space Station Experiment (MISSE) platformwe give evidence that Earth-commercial ibuprofen tablets could fail in space, despite encasing in a commercial pharmacy aluminum-blister. We introduce the concept of ‘space medicines’, where solid-dosage forms are formulated with excipients, such as iron oxide, to protect the pharmaceutical active from accelerated degradation in spaceflight. We apply Earth radionuclide and photon experiments to simulate dose(s) in ISS and significantly greater, and establish the impact of alpha, beta and gamma rays. We demonstrate that tablet formulation protects from impact of alpha and beta rays; however, gamma rays decompose ibuprofen even when ‘masked’. Importantly, we show all rays decompose ‘unmasked’ pure ibuprofen. We report for the first time a systematic analysis, of nineteen (19) tablet compositions, inside and outside of ISS that permit determination of the effect of compositional changes of the tablet matrix. We confirm that the iron oxide-shielded tablets, according to our four-fold degradation descriptor rating, had ‘minimal’ reduction of ibuprofen content (10%); with one exception. The tablets exhibited much greater ibuprofen degradation (> 30-50%) outside ISS at the MISSE platform, which permits exposure to harsh conditions including extreme temperature fluctuation, ultraviolet radiation, highly reactive atomic oxygen, and micrometeoroids. Significantly, we find that the flavor has shielding potential, most likely because of radical scavenging. We conclude that efficacy of ibuprofen is adversely affected in space, and that effects will likely be exacerbated on missions to deeper space e.g., to moon and Mars.

Bacterial contamination during space missions is problematic for human health and damages filters and other vital support systems. Staphylococcus aureus is both a human commensal and an opportunistic pathogen that colonizes human tissues and causes acute and chronic infections. Virulence and colonization factors are positively and negatively regulated, respectively, by bacterial cell-to-cell communication (quorum sensing) via the agr (accessory gene regulator) system. When cultured under low-shear modelled microgravity conditions (LSMMG), S. aureus has been reported to maintain a colonization rather than a pathogenic phenotype. Here, we show that the modulation of agr expression via reduced production of autoinducing peptide (AIP) signal molecules was responsible for this behavior. In an LSMMG environment, the S. aureus strains JE2 (methicillin-resistant) and SH1000 (methicillin-sensitive) both exhibited reduced cytotoxicity towards the human leukemia monocytic cell line (THP-1) and increased fibronectin binding. Using S. aureus agrP3::lux reporter gene fusions and mass spectrometry to quantify the AIP concentrations, the activation of agr, which depends on the binding of AIP to the transcriptional regulator AgrC, was delayed in the strains with an intact autoinducible agr system. This was because AIP production was reduced under these growth conditions compared with the ground controls. Under LSMMG, S. aureus agrP3::lux reporter strains that cannot produce endogenous AIPs still responded to exogenous AIPs. Provision of exogenous AIPs to S. aureus USA300 during microgravity culture restored the cytotoxicity of culture supernatants for the THP-1 cells. These data suggest that microgravity does not affect AgrC-AIP interactions but more likely the generation of AIPs.

Background: Understanding and countering the well-established negative health consequences of spaceflight remains a primary challenge preventing safe deep space exploration. Targeted/personalized therapeutics are at the forefront of space medicine strategies, and cross-species molecular signatures now define the ‘typical’ spaceflight response. However, a lack of direct genotype–phenotype associations currently limits the robustness and, therefore, the therapeutic utility of putative mechanisms underpinning pathological changes in flight. Methods: We employed the worm Caenorhabditis elegans as a validated model of space biology, combined with ‘NemaFlex-S’ microfluidic devices for assessing animal strength production as one of the most reproducible physiological responses to spaceflight. Wild-type and dys-1 (BZ33) strains (a Duchenne muscular dystrophy (DMD) model for comparing predisposed muscle weak animals) were cultured on the International Space Station in chemically defined media before loading second-generation gravid adults into NemaFlex-S devices to assess individual animal strength. These same cultures were then frozen on orbit before returning to Earth for next-generation sequencing transcriptomic analysis. Results: Neuromuscular strength was lower in flight versus ground controls (16.6% decline, p < 0.05), with dys-1 significantly more (23% less strength, p < 0.01) affected than wild types. The transcriptional gene ontology signatures characterizing both strains of weaker animals in flight strongly corroborate previous results across species, enriched for upregulated stress response pathways and downregulated mitochondrial and cytoskeletal processes. Functional gene cluster analysis extended this to implicate decreased neuronal function, including abnormal calcium handling and acetylcholine signaling, in space-induced strength declines under the predicted control of UNC-89 and DAF-19 transcription factors. Finally, gene modules specifically altered in dys-1 animals in flight again cluster to neuronal/neuromuscular pathways, suggesting strength loss in DMD comprises a strong neuronal component that predisposes these animals to exacerbated strength loss in space. Conclusions: Highly reproducible gene signatures are strongly associated with space-induced neuromuscular strength loss across species and neuronal changes in calcium/acetylcholine signaling require further study. These results promote targeted medical efforts towards and provide an in vivo model for safely sending animals and people into deep space in the near future.