Bo Yi

Oral delivery of small-molecule drugs to the distal intestine is often hindered by short colonic retention, a key requirement for ensuring sustained colonic drug availability. Herein, we developed a library of minimalist, muco-infiltrating prodrug coacervates by exploiting the interfacial physics of liquid–liquid phase separation (LLPS). By systematically tuning the length of poly(ethylene glycol) (PEG) spacer and the hydrophobicity of drug stickers in PEG–drug conjugates, we precisely modulated the molecular amphiphilicity to generate liquid coacervates with ultralow interfacial tension against water (< 1 mN/m). These liquid coacervates actively spread across and infiltrate the freshly isolated intestinal mucus in vitro. As a proof-of-concept, butyrate coacervate (P6-ButCoa) accumulated in the cecum and colon within 2 hours post-oral administration and persisted for over 18 hours. The prolonged colonic retention time facilitates sustained, enzyme-responsive drug release, which significantly ameliorates dextran sulfate sodium (DSS)-induced colitis and associated depressive behaviors by markedly enhancing drug availability primarily in the colon, with subsequent bioavailability in the brain. These findings demonstrate that leveraging interfacial physics to guide mucus infiltration of coacervates offers a versatile strategy for sustained oral drug delivery to the distal intestine.

The evolution of bioadhesive from simple and passive glues to dynamic and intelligent systems represents a paradigm shift in biomedical and engineering applications. While conventional bioadhesives offer biocompatibility and firm adhesion, they often lack the spatiotemporal precision and responsive capabilities required for advanced therapies. In this review, we explore the burgeoning field of intelligent bioadhesion, which is featured with built‐in responsiveness and adaptiveness for specific environmental or external fields. We discuss the design principles underpinning these smart materials, including the integration of stimuli‐responsive polymers, biomimetic motifs, and nano/micro‐scale components. Key applications are highlighted to demonstrate their transformative potential in targeted drug delivery, integrated biointerfaces, and minimally invasive surgeries. We envision that the fusion of sophisticated material designs with intelligent technologies is paving the way for a new generation of bioadhesives capable of precise, dynamic, and interactive control, ultimately bridging the critical gap between passive, static adhesion and active, intelligent tissue integration.

Developing adhesives with robust underwater adhesion to diverse substrates, particularly highly hydrated and lipidic substrates, remains a major challenge. Inspired by the tough adhesion of barnacles on marine creatures, here we report a dilution-resistant and superspreading coacervate to mediate robust underwater adhesion by enabling interfacial infiltration and intertwining. Conjugation of terminal butyl groups to poly(propylene glycol) (PPG) triggers liquid-liquid phase separation of the aqueous solution and formation of PPG coacervate driven by the hydrogen bonding and hydrophobic interactions. The simple coacervate shows distinctive superspreading properties to facilitate interfacial wetting, infiltration and formation of intertwined interfaces on both the hydrated and lipidic substrates and concentrates the loaded hydrophilic curing agents to form a robust underwater adhesive by rapid in situ photocuring. The coacervate-based adhesive demonstrates strong underwater adhesion to diverse substrates, including highly hydrated and lipidic substrates with multiscale porosity and in complex aqueous environments. Potential applications of this adhesive are validated by robust adhesion-mediated hydrogel and/or organogel assemblies and effective sealing of underwater leakages and tissue perforations.

Liquid metal (LM) composites are a class of emerging soft multifunctional materials that are promising for a variety of applications, yet the chemistry properties of LM have not been fully understood. Here, we report that LM nanoparticles can directly perform as a photoinitiator for radical polymerization and the in situ development of highly tough and multifunctional LM hydrogel composites. It is revealed that the photocatalytic activity of LM nanoparticles originates from the oxide layer on LM. Significantly, positively charged metal-organic framework (MOF) nanoparticles are used to stabilize LM nanoparticles in aqueous solutions, where the MOF can anchor on the surface of LM nanoparticles by electrostatic interaction while helping to preserve the unshielded oxide layer, therefore realizing the highly efficient photoinitiation and polymerization. The LM nanoparticle-initiated photopolymerization is shown to develop hydrogel composites featuring excellent stretchability, stimuli responsiveness, and sustained photocatalytic activity. The photocatalytic polymerization initiated by LM nanoparticles not only deepens the understanding on the semiconductor properties of the oxide skin on LM but also broadens the application scenarios of multifunctional LM/polymer composites in smart materials, wearable electronics, and soft robotics.

Flexible actuation of droplets is crucial for biomedical and industrial applications. Hence, various approaches using optical, electrical, and magnetic forces have been exploited to actuate droplets. For broad applicability, an ideal approach should be programmable and be able to actuate droplets of arbitrary size and composition. Here we present an “additive-free” magnetic actuation method to programmably manipulate droplets of water, organic, and biological fluids of arbitrary composition, as well as solid samples, on a ferrofluid-infused porous surface. We specifically exploit the spontaneously formed ferrofluid wetting ridges to actuate droplets using spatially varying magnetic fields. We demonstrate programmed processing and analysis of biological samples in individual drops as well as the collective actuation of large ensembles of micrometer-sized droplets. Such model respiratory droplets can be accumulated for improved quantitative and sensitive bioanalysis - an otherwise prohibitively difficult task that may be useful in tracking coronavirus.

The adaptive polar–polar interactions between the PVDF copolymer and the gallium oxide layer bring advantageous manipulation of LM compartments in the polymer matrix, offering stable conductivity under continuous stretching.

Using antimicrobial coatings to control the spread of pathogenic microbes is appreciated in public and healthcare settings, but the performance of most antimicrobial coatings could not fulfill the increasing requirements, particularly the ease of preparation, high durability, rapid response, and high killing efficiency. Herein, we develop a new type of mechano-induced assembly of nanocomposite coating by simple “Press-N-Go” procedures on various substrates such as glassware, gloves, and fabrics, in which the coating shows strong adhesion, high shear stability, and high stiffness, making it durable in daily use to withstand common mechanical deformation and scratches. The coating also shows remarkable disinfection effectiveness over 99.9% to clinically significant multiple drug-resistant bacterial pathogens upon only 6 s near-infrared irradiation, which can be further improved to over 99.9999% upon another 6 s treatment. We envision that the coating can provide convenience and values to control pathogen spread for easily contaminated substrates in high-risk areas.

Here, a superhydrophobic and catalytically active metal–organic framework (MOF) coating is reported by coordination‐driven assembly of MOF nanoparticles and a catechol‐functionalized polysiloxane polymer. This MOF coating can be fabricated by casting MOF‐polymer precursor onto diverse substrates with varied coating techniques, for example, spray coating, bar coating, and dip coating. The catechol‐functionalized polymer can not only coordinate to the open metal sites on MOF surface which enables the surface functionalization and assembly of MOF nanoparticles, but also allow non‐covalent interactions with casting substrates—thus improving the substrate adhesion of the MOF coating. With the well‐preserved porosity and surface hydrophobicity, the MOF coating demonstrates superhydrophobicity as well as improved catalytic activity toward the Knoevenagel condensation at room temperature. Such coordination‐driven assembly approach can be extended to a range of MOF systems for preparing highly functional composite materials toward various applications.

Wound-associated infections create additional suffering and come at a high cost for patients and their families, which urgently require wound disinfection biomaterials with improved healing efficacy. Here, we report an adhesive with sustained bacteria disinfection ability, which is aggregated from hydrogen-bonded polymer particulates. The particulate-aggregated adhesive shows strong binding ability on different surfaces from rigid substrates to soft skins. Moreover, water-sensitive mechanical properties are shown in wound exudates, resulting from the dissociation of hydrogen bonds under the competition of water and thus the sustained release of particulates. Synergizing with the strong binding ability, exudate-sensitive behaviors, and sustained release of antibacterial particulates, the adhesive achieves sustained bactericidal activity and can facilitate the healing process in bacteria-infected skin wounds.