In a groundbreaking advance poised to transform biomedical devices and environmental monitoring, researchers have unveiled a revolutionary underwater adhesive technology designed explicitly for soft, dynamic substrates. This innovative system, termed the MUSAS (Mechanical Underwater Soft Adhesive System), exhibits remarkable adaptability and stability even under extreme and unpredictable environmental conditions. By seamlessly attaching to delicate biological surfaces without compromising their natural function, MUSAS opens unprecedented opportunities for in vivo biosensing, targeted drug delivery, and localized gene therapy. Its resilience and multifunctionality are destined to reshape the frontiers of bioelectronic interface and medical treatments, all while operating wirelessly and non-invasively in complex living systems.
The first striking demonstration of MUSAS’s prowess involved kinetic temperature sensing on live tilapia fish. These aquatic models represent authentic, unstructured environments where bioelectronics often falter due to the challenges posed by moisture, movement, and soft tissue interfaces. The researchers developed an ultraminiaturized, battery-free radiofrequency identification (RFID) temperature sensor, measuring a mere 1.3 by 6 by 12 millimeters, capable of wireless operation over a one-meter range. When affixed to various anatomical sites on tilapia—including the operculum, head, and body—MUSAS maintained stable adhesion for up to 110 hours. Importantly, this did not inhibit critical behaviors such as swimming or feeding, confirming its biocompatibility and functional imperceptibility.
Wireless kinetic temperature measurements on freely swimming tilapia further underscored the platform’s potential for real-time environmental and physiological monitoring. Such capability is vital for ecological studies that aim to understand the nuanced needs and social behaviors of aquatic species in their natural habitat. Conventional sensors often require cumbersome invasive attachments or external tethers, limiting animal movement and the fidelity of data. MUSAS’s battery-free and microneedle-facilitated adhesion system marks a paradigm shift, enabling truly unobtrusive biosensing with reliable signal transmission despite the chaotic underwater milieu.
Beyond ecological applications, the MUSAS platform addresses pressing challenges in clinical medicine, notably in the digital health monitoring of gastroesophageal reflux disease (GERD). Affecting millions globally, GERD diagnosis conventionally relies on devices like the Bravo capsule, which employs invasive needle-like clips to affix to the esophageal mucosa, often causing patient discomfort. MUSAS leverages its self-adhesive microneedle architecture to house a flexible impedance sensor that detects subtle pH fluctuations associated with reflux events without invasive installation. In rigorous swine gastric fluid reflux models, this sensor repeatedly and accurately recorded the onset and intensity of gastric reflux induced via controlled endoscopic fluid sprays. Such reliable, non-invasive monitoring technology promises to redefine patient compliance and comfort in managing chronic GERD.
Extending its remarkable retention and adhesive properties, MUSAS paves the way for innovative solutions in sustained pharmacological delivery within the gastrointestinal (GI) tract. In the context of HIV prevention, an urgent public health concern with over 40 million affected globally, long-acting injectable prophylaxes such as cabotegravir (CAB) face challenges like intense initial dosing burdens and frequent clinic visits that hinder adherence. The research team engineered a novel ingestible, slow-release MUSAS-enabled formulation incorporating polycaprolactone and Ecoflex elastomers as biodegradable matrices. These materials demonstrated optimal drug release profiles in vitro, ensuring consistent therapeutic levels over extended periods.
Crucially, translational in vivo studies in swine models validated that these MUSAS-based CAB delivery systems maintain sustained release over a seven-day observational window, thereby heralding a new caliber of orally administered PrEP that could dramatically improve patient adherence and accessibility. The robust retention of the adhesive matrix in the dynamic GI environment assures prolonged contact time and controlled pharmacokinetics, addressing critical barriers that have long limited oral delivery strategies for long-acting antivirals.
Perhaps the most transformative application of MUSAS lies in overcoming the formidable biological obstacles to efficient mRNA therapeutics delivery within the GI tract. Delivering nucleic acid-based medications orally has been notoriously challenging due to mucosal barriers, enzymatic degradation, and systemic immunogenicity. The team utilized MUSAS as a microneedle adhesive platform to deploy lipid nanoparticle-encapsulated firefly luciferase mRNA within mucosal tissues of the buccal and pharyngeal regions in swine. The microneedles enabled mechanical penetration beyond the mucus surface, enhancing local drug uptake while minimizing systemic exposure.
Remarkably, a substantial payload volume of 215 microliters was effectively delivered, demonstrating exceptional drug-loading capacity. Tissue-specific expression of luciferase was confirmed via sensitive bioluminescent imaging and corroborated through immunofluorescent histological analysis, affirming robust transfection efficiency. This pioneer approach not only surmounts the limitations of conventional mucosal delivery but also unlocks future avenues for oral mucosal vaccines and targeted gene therapies against GI disorders like Crohn’s disease.
Underpinning all these applications is MUSAS’s unique combination of mechanical design and material composition, enabling underwater adhesion to ultrasoft substrates with minimal invasiveness. The microneedle arrays physically interlock with the substrate, while specialized polymer matrices maintain strong adhesion even in wet, dynamic environments. This synergy culminates in a universally applicable platform that can be fine-tuned across scales and anatomical locations, from fish gills to human esophageal mucosa and gastrointestinal lining.
The integration of wireless electronics, in the form of miniature RFID temperature sensors and flexible impedance pH sensors, further enhances MUSAS’s utility by providing real-time, remote physiological data without tethering subjects or requiring bulky power sources. Such capabilities address long-standing technical bottlenecks in continuous biosensing, creating new paradigms for patient monitoring, wildlife ecology, and clinical diagnostics.
Biocompatibility assessments revealed that MUSAS devices cause negligible tissue disruption or behavioral alterations, critical for applications requiring prolonged in vivo residence. The facile attachment and detachment, combined with sustained retention times, facilitate diverse biomedical interventions without necessitating invasive procedures or surgical implantation.
Moreover, the versatility of the MUSAS platform fosters seamless adaptation to emerging biomedical needs, underscoring its value as a foundational technology in soft bioelectronics. Its scalable fabrication techniques and modular design promise swift translational pathways from bench to bedside, facilitating rapid deployment in ecological studies, personalized medicine, and next-generation drug delivery systems.
The research delineated here exemplifies an elegant intersection of materials science, mechanical engineering, and biomedical innovation. It showcases how bioinspired adhesive strategies, when integrated with wireless sensing and precise drug release mechanics, can yield dynamic solutions to longstanding challenges in healthcare and environmental science. As the MUSAS technology matures, it will likely catalyze transformative breakthroughs across disciplines, heralding a new era where bioelectronics seamlessly interface with living, moving substrates in their native environments.
In conclusion, MUSAS represents a quantum leap in underwater soft adhesives tailored for multifunctional biosensing and therapeutic delivery. By harmonizing microneedle adhesion with wireless, battery-free sensing modalities and sustained drug release matrices, it surmounts critical barriers in ecological monitoring, chronic disease management, HIV prophylaxis, and gene therapy. The capability to adhere reliably to delicate tissues in wet, unstructured biological environments while enabling precise monitoring and treatment heralds MUSAS as a landmark platform in the journey toward truly integrated bioelectronic medicine.
Subject of Research: Mechanical underwater adhesive devices designed for soft biological substrates enabling multifunctional applications such as in vivo biosensing, digital health monitoring, sustained drug delivery, and mucosal mRNA therapeutics.
Article Title: Mechanical underwater adhesive devices for soft substrates
Article References:
Kang, Z., Gomez, J.A., Ross, A.M. et al. Mechanical underwater adhesive devices for soft substrates. Nature (2025). https://doi.org/10.1038/s41586-025-09304-4
Image Credits: AI Generated
