From Passive Monitoring to Active Control: Aggregation‐induced Emission‐driven Antimicrobial Nanotechnology for Long‐duration Spaceflight

Humanity has entered a new phase of space exploration in which long-term orbital habitats are becoming routine. Within these permanently inhabited, hermetically sealed modules, microbial safety has emerged as a pivotal determinant of crew health and mission reliability. Closed circulation of air and water, together with the altered physiology and virulence of microorganisms in micro-gravity, renders conventional, Earth-based control measures insufficient and calls for space-specific innovations. Against this backdrop, China's rapid progress in astronautics, exemplified by the successful assembly and sustained operation of the Tiangong Space Station, has become a powerful catalyst for the development of next-generation microbial monitoring and abatement technologies. To tackle this challenge, a landmark research programme has been initiated, which is supported by the “Space Station Program Technology Demonstration Experiments” initiative and led by Professors Yulin Deng and Ying Zhang from Beijing Institute of Technology. A central component is the “aggregation-induced emission (AIE)-armed bionic nanostructure module,” a cutting-edge integrated system that merges multidisciplinary expertise. Its key subsystems are the product of collaboration among three leading teams: AIE fluorophores, developed by Academician Ben Zhong Tang's group at The Chinese University of Hong Kong (Shenzhen); Bionic nanostructures, engineered by Professors Zuowan Zhou and Xiaoling Xu at Southwest Jiaotong University; The intelligent antimicrobial control logic was developed by the engineering team led by Mr. Qihuan Xiong at Changsha XiangJi-Hiden Technology Co., Ltd.and Dr. Chunhua Yang at Beijing Genxin Technology Co., Ltd. This innovative module achieves a critical breakthrough: it simultaneously enables real-time microbial imaging and active pathogen eradication, thus addressing the dual challenge of rapid detection and effective suppression of microorganisms in the space environment. Launched at 05:34 CST on 15 July 2025 from the Wenchang Space Launch Center, the Tianzhou-9 cargo spacecraft delivered the first batch of in-orbit experimental materials for this microbial monitoring and protection project. Beyond its immediate technical goals, this mission symbolises China's strategic commitment to solving the fundamental biosafety challenges of long-duration space habitation through convergent, state-of-the-art technological solutions—paving the way for safer, more sustainable human presence in orbit and beyond. Although the space environment is inherently inimical to most terrestrial microorganisms, complete sterility aboard orbiting platforms remains unattainable. Contaminants accompany every launch vehicle, propagate via crew activities, and are introduced through experimental payloads, thereby establishing complex microbial consortia within the closed ecological loops of a space station. Once established, these communities give rise to three interrelated hazards (Figure 1). First, the formation of resilient biofilms accelerates material degradation and bio-corrosion, threatening the integrity of air-handling ducts, water-recovery assemblies, and load-bearing structures [1, 2]. Second, biofouling within fluid circuits progressively occludes filters and pipework, increasing hydraulic resistance and jeopardising the reliability of life-support subsystems [2]. Third, chronic exposure to biofilm-associated pathogens and their metabolic toxins undermines crew immunocompetence and elevates the incidence of opportunistic infection [2, 3]. Mitigating these risks demands an integrated control paradigm that couples high-efficacy sterilisation with continuous bio-surveillance and rapid, in-situ remediation. To satisfy stringent planetary-protection requirements, guarantee crew health and preserve the performance of on-board hardware, contemporary space programmes employ a suite of physical, chemical, and surface-engineering strategies for microbial control (Table 1). Dry-heat sterilisation remains the benchmark non-chemical intervention for hardware that can tolerate elevated temperatures. Components are typically held at 110–125°C for several hours, a protocol validated during the Viking era and still recommended in current planetary-protection standards. Its appeal lies in the absence of chemical residues and the proven lethality of sustained thermal exposure to highly resilient spores such as Bacillus spp [1]. The efficacy of the method, however, is exquisitely sensitive to precise temperature mapping and uniform heat transfer; even modest spatial gradients can prolong D-values and compromise sterility assurance. Complementary physical techniques—ultraviolet-C irradiation for surface passes, or vacuum baking to desiccate latent bio-burdens—are occasionally combined with dry heat when mission timelines permit, although their penetration depth and shadowing effects impose practical limits on stand-alone use. When hardware is heat-labile or rapid turnaround is required, low-residue biocides become indispensable. On the International Space Station (ISS), for instance, the Japanese Experiment Module (Kibo) is wiped with 70% isopropyl alcohol before launch and is subsequently maintained in orbit with benzalkonium-chloride solutions, a protocol that keeps surface bioburden beneath mission-defined alert thresholds [3]. Such quaternary ammonium compounds, together with peracetic acid vapour or hydrogen-peroxide mist, provide broad-spectrum kill at room temperature and short contact times. A recognised drawback is the selective pressure they impose: repeated sub-lethal exposures can enrich for intrinsically tolerant taxa or drive adaptive resistance, necessitating periodic rotation of actives and routine molecular surveillance of the cabin microbiome. Microgravity alters fluid dynamics and microbial physiology, frequently accelerating biofilm development on flight hardware. To disrupt this process at its inception, functional coatings have been engineered to release biocidal ions, generate reactive oxygen species, or present anti-adhesive chemistries. Recent formulations that couple contact-killing moieties with quorum-sensing inhibitors have demonstrated significant suppression of Pseudomonas and Staphylococcus biofilms in ground-based simulators and in orbital flight tests [2]. Parallel efforts have focused on lubricant-impregnated textured surfaces; investigations aboard the ISS recorded up to an 86% reduction in adherent biomass relative to unmodified controls, an effect attributed to the physical destabilisation of the nascent extracellular matrix [4]. The current consensus favours layered countermeasures in which an anti-adhesive or contact-active coating is paired with periodic mechanical or chemical cleansing, thereby minimising initial attachment while ensuring that any residual microcolonies are subsequently eradicated [5]. Central to this approach is the disruption of intracellular second messengers such as cyclic di-GMP, a pivotal regulator of the sessile-planktonic switch that underpins mature biofilm development. Collectively, these integrated physical, chemical, and materials-science solutions represent a convergent strategy aimed at maintaining spacecraft within prescribed bioburden limits while accommodating the operational constraints of long-duration missions. As space exploration advances toward longer-duration voyages and planetary habitats, issues such as the increased tendency of microorganisms to form biofilms and the uncontrollability of their pathogenicity will become increasingly prominent. This has rendered traditional methods inadequate in terms of real-time performance and long-term effectiveness. Aggregation-induced emission, first reported by Ben Zhong Tang and co-workers in 2001, marks a fundamental departure from the photophysical behaviour of conventional luminophores. While most organic fluorophores undergo aggregation-caused quenching at elevated concentrations, AIE luminogens (AIEgens) display markedly intensified emission in the condensed or solid state. This distinctive phenomenon is generally attributed to the restriction of intramolecular motion (RIM) that accompanies molecular aggregation. Once the intramolecular rotations and vibrations are constrained, non-radiative decay channels are largely suppressed, allowing the radiative transition to dominate. As a consequence, AIEgens combine high solid-state quantum yields with exceptional photostability, minimal self-quenching even at high local concentrations, and readily tunable emission profiles. Their low cytotoxicity and favourable signal-to-noise characteristics further underscore their appeal for bio-oriented applications. The unique photophysical attributes of AIEgens have stimulated a broad spectrum of bioanalytical and biomedical innovations. In live-cell microscopy, they routinely furnish intense, photostable signals that enable long-term observation of cellular dynamics with negligible phototoxicity. Structural derivatisation strategies have yielded probes with pronounced affinity for specific organelles, thereby facilitating high-contrast sub-cellular imaging as well as three-dimensional visualisation of tissue sections [6]. Beyond imaging, AIE platforms have emerged as sensitive reporters for pathogen detection. By judiciously coupling AIE luminophores with targeting ligands or environmentally responsive moieties, researchers have achieved rapid discrimination between bacterial species, real-time monitoring of microbial proliferation, and facile differentiation of viable from non-viable cells. The same design logic has been extended to visualise and characterise biofilms, a task that remains challenging for traditional fluorophores because of self-quenching and background interference. Therapeutically, AIE molecules serve a dual role as diagnostic tracers and functional agents. Many AIEgens possess appreciable triplet yields or can be engineered to do so, rendering them efficient photosensitisers for photodynamic therapy. Their bright fluorescence enables image-guided delivery, whereas their capacity for reactive oxygen species generation confers therapeutic efficacy. Integrated “theranostic” constructs relying on AIE scaffolds thus provide simultaneous disease localisation, treatment, and response monitoring. In parallel, antimicrobial AIE photosensitisers have shown promise for eradicating drug-resistant pathogens and disrupting resilient biofilms [7]. Collectively, the fundamental RIM mechanism endows AIE technology with a suite of photophysical advantages that translate into versatile, high-performance tools for contemporary life-science research and precision medicine. The Tianzhou-9 mission carries an AIE-armed bionic nanostructure module expressly conceived to meet the stringent demands of microbial surveillance and mitigation in the space-station environment. Developed under the leadership of Academician Ben Zhong Tang, the platform exploits the team's pioneering AIE technology, which affords real-time, in-situ visualization of microbial populations while simultaneously enabling rapid bactericidal intervention. In partnership with Southwest Jiaotong University, the researchers have embedded AIE luminogens within a biomimetic antimicrobial nanostructure capable of triggering on-demand sterilization during flight. Under microgravity conditions, the module rigorously evaluates the efficacy of diverse physical, chemical, and hybrid sterilization mechanisms, delivering quantitative data with high sensitivity, swift response, operational simplicity, and long-term stability. Its successful deployment establishes a robust microbiological safety barrier for extended crewed missions and, by validating this advanced technology in orbit, promises to accelerate terrestrial applications in clinical infection control, industrial hygiene, and public health (Figure 2). The integration of AIE technology with bionic nanostructures represents a transformative advancement in microbial management for long-duration spaceflight. The AIE-armed bionic nanostructure module, deployed aboard the Tianzhou-9 cargo spacecraft, successfully bridges critical gaps in current space station microbial control strategies by enabling: 1. Real-Time Pathogen Monitoring: AIE luminogens provide high-sensitivity, photostable fluorescence imaging for in-situ detection of microbial proliferation and biofilm formation, overcoming the limitations of traditional passive monitoring. 2. Active, Resistance-Free Sterilization: The synergistic combination of AIE-driven photodynamic action and biomimetic nanostructures achieves rapid, adaptive pathogen eradication without inducing microbial resistance—a key drawback of chemical disinfectants. 3. Enhanced Mission Safety: By simultaneously addressing microbial detection and elimination, the module significantly mitigates risks to crew health (e.g., opportunistic infections) and hardware integrity (e.g., bio-corrosion) in confined space environments. This paradigm shift—from reactive to proactive microbial control—has been validated under microgravity conditions during the Tianzhou-9 mission, demonstrating unparalleled operational robustness and long-term stability. The technology's success not only fortifies biosafety protocols for China's space station but also pioneers scalable solutions for terrestrial challenges in clinical hygiene, water purification, and industrial biofilm management. This work was supported by the “Space Station Program Technology Demonstration Experiments”. The authors express profound gratitude to engineers and technical staff at the Wenchang Space Launch Center for their critical contributions to the Tianzhou-9 launch operations. We further acknowledge the unwavering dedication of all unsung heroes across China's aerospace ecosystem—including system integrators, quality assurance specialists, and mission support personnel—whose relentless efforts behind the scenes safeguard the success of space science endeavors. Special thanks are extended to Changsha XiangJi-Hiden Technology Co., Ltd., Beijing Genxin Technology Co., Ltd. and Beijing Genshu Technology Co., Ltd. for their engineering and manufacturing expertise. The authors declare no conflicts of interest.