Gelatin-based biomaterials have emerged as promising candidates for bioadhesives due to their biodegradability and biocompatibility. However, they often face limitations due to the uncontrollable phase transition of gelatin, which is dominated by hydrogen bonds between peptide chains. Here, we developed controllable phase transition gelatin-based (CPTG) bioadhesives by regulating the dynamic balance of hydrogen bonds between the peptide chains using 2-hydroxyethylurea (HU) and punicalagin (PA). These CPTG bioadhesives exhibited significant enhancements in adhesion energy and injectability even at 4 °C compared to traditional gelatin bioadhesives. The developed bioadhesives could achieve self-reinforcing interfacial adhesion upon contact with moist wound tissues. This effect was attributed to HU diffusion, which disrupted the dynamic balance of hydrogen bonds and therefore induced a localized structural densification. This process was further facilitated by the presence of pyrogallol from PA. Furthermore, the CPTG bioadhesive could modulate the immune microenvironment, offering antibacterial, antioxidant, and immune-adjustable properties, thereby accelerating diabetic wound healing, as confirmed in a diabetic wound rat model. This proposed design strategy is not only crucial for developing controllable phase-transition bioadhesives for diverse applications, but also paves the way for broadening the potential applications of gelatin-based biomaterials.

Real‐time deployment of adhesives and achieving long‐term and high‐strength adhesion in various harsh environments remains a significant challenge both in the engineering field and daily life. Herein, the authors report the construction of a super adhesive based on an entirely new mechanism of zwitterion‐initiated polymerization. This adhesive can be formed quickly by the rapid spontaneous polymerization of 4‐aminostyrene (4‐AS) in the presence of acidic polyanion aqueous solution initiated by zwitterions. Direct adhesion and curing process of the adhesive is independent of the environment, and it can be completely cured within 20 min to strongly glue diverse materials spanning from plastics to inorganic substances and metal in various environments (water, acid, alkali, seawater, oil, organic solvent, and low temperature), supposedly due to their marvelous ability to repel the surface liquid barrier layer and form multiple interactions with adherend. Remarkably, this adhesive can maintain high‐strength and long‐term adhesion to different materials surfaces, quickly repairing broken containers in various conditions. The zwitterion‐initiated spontaneous polymerization provides a new strategy for constructing an eco‐benign high‐strength adhesive with an ability to bond a wide variety of materials with long‐term stability against various severe environments.

The amount of dopamine (DA) in the body is closely related to the occurrence and development of Parkinson's disease. However, DA detection in real body fluids is still challenging. Here, we developed a high-selectivity and high-sensitivity label-free lanthanide metal organic frameworks (MOFs) to monitor DA in urine samples from Parkinson's patients. The fluorescent MOF Eu-alpha-cyclodextrin (CD), prepared by biomineralization under mild conditions, exhibited DA concentration-dependent fluorescence intensity via host-guest complexation. Furthermore, molecular dynamics (MD) simulation analyses quantitatively dissect thermodynamic interactions of cyclodextrin and guest molecules, which systematically reveals the specific recognition mechanism of cyclodextrin and dopamine molecules. A good response for DA in the range of 10(-9) to 10(-4) M and a limit of detection (LOD) of 0.65 nM were obtained, consistent with the detection range of DA in a variety of biological fluids. Because of the good anti-interference properties of this complex, visual test strips were prepared by the in-situ growth of Eu-alpha CD nanoparticles on a nitrocellulose (NC) membrane at room temperature, owing to the protein absorbability of NC membranes. The resultant test strips possess the potential for semiquantitative detection of DA by the naked eye. Moreover, we applied Eu-alpha CD nanoparticles to analyze clinical urine samples from Parkinson's patients, and achieved a low relative error compared with those of commercial HPLC methods. Our work offers an efficient strategy for visual and on-site detection of DA in the clinic, which can assist in early diagnosis of Parkinson's disease.