Designing a Hypoxia-Activated Sensing Platform Using an Azo Group-Triggered Reaction with the Formation of Silicon Nanoparticles.

Hypoxia is known as a specific signal of various diseases, such as liver fibrosis. We designed a hypoxia-sensitive fluorometric approach that cleaved the azo bond (N═N) in the presence of hypoxia-controlled agents (sodium dithionite and azoreductase). 4-(2-Pyridylazo) resorcinol (Py-N═N-RC) bears a desirable hypoxia-responsive linker (N═N), and its azo bond breakup can only occur in the presence of sodium dithionite and azoreductase and leads to the release of 2,4-dihydroxyaniline, which can react with 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane to generate yellow fluorescent silicon nanoparticles.

Surface-Confined Piezocatalysis Inspired by ROS Generation of Mitochondria Respiratory Chain for Ultrasound-Driven Noninvasive Elimination of Implant Infection.

Implant-associated infections (IAI) are great challenges to medical healthcare and human wellness, yet current clinical treatments are limited to the use of antibiotics and physical removal of infected tissue or the implant. Inspired by the protein/membrane complex structure and its generation of reactive oxygen species in the mitochondria respiration process of immune cells during bacteria invasion, we herein propose a metal/piezoelectric nanostructure embedded on the polymer implant surface to achieve efficient piezocatalysis for combating IAI. The piezoelectricity-enabled local electron discharge and the induced oxidative stress generated at the implant-bacteria interface can efficiently inhibit the activity of the attachedby cell membrane disruption and sugar energy exhaustion, possess high biocompatibility, and eliminate the subcutaneous infection by simply applying the ultrasound stimulation.

Stem cell microencapsulation maintains stemness in inflammatory microenvironment.

Maintaining the stemness of the transplanted stem cell spheroids in an inflammatory microenvironment is challenging but important in regenerative medicine. Direct delivery of stem cells to repair periodontal defects may yield suboptimal effects due to the complexity of the periodontal inflammatory environment. Herein, stem cell spheroid is encapsulated by interfacial assembly of metal-phenolic network (MPN) nanofilm to form a stem cell microsphere capsule.

Microencapsulation of Ionic Liquid by Interfacial Self-Assembly of Metal-Phenolic Network for Efficient Gastric Absorption of Oral Drug Delivery.

Improving bioavailability of orally delivered drugs is still challenging, as conventional drug delivery systems suffer from non-specific drug delivery in the gastrointestinal (GI) tract and limited drug absorption efficiency. Gastric drug delivery is even more difficult due to the harsh microenvironment, short retention time, and physiologic barriers in the stomach. Here, an oral drug delivery microcapsule system was developed for gastric drug delivery, which consists of ionic liquid (IL) as the inner carrier and metal-phenolic network (MPN) as the microcapsule shell.

Metal Phenolic Nanodressing of Porous Polymer Scaffolds for Enhanced Bone Regeneration via Interfacial Gating Growth Factor Release and Stem Cell Differentiation.

Porous polymer scaffolds are essential materials for tissue engineering because they can be easily processed to deliver stem cells or bioactive factors. However, scaffolds made of synthetic polymers normally lack a bioactive cell-material interface and undergo a burst release of growth factors, which may hinder their further application in tissue engineering. In this paper, a metal-phenolic network (MPN) was interfacially constructed on the pore surface of a porous poly(dl-lactide) (PPLA) scaffold.

Metal-phenolic network coatings for engineering bioactive interfaces.

The surface modification of biomaterials is crucial for constructing bioactive interfaces capable of interacting with specific biomolecules, controlling cell behavior and regulating biological processes. Because of their excellent biocompatibility, facile preparation, pH-responsiveness and universal adhesion, surface coatings made from metal-phenolic network (MPN) have attracted extensive attention for handling interfacial properties and designing biomaterials in recent years. Different methods and technologies for assembling MPN coatings are summarized and compared in this paper, followed by highlighting the advantages of MPN coatings as bioactive interfaces for controlling biological process at the molecular, cellular, and tissue levels.