Interfacides

Interfacides are a proposed class of molecular or supramolecular actors that localize at interfaces and modulate the physics and chemistry of the boundary between two distinct systems, most commonly biological tissue and an artificial material such as an implant, sensor, or scaffold. By altering protein adsorption, hydration layers, charge distribution, and surface energy, interfacides influence cellular responses, integration, and function at the interface.

The term combines interfacial and facies (face), reflecting their role at boundary surfaces. The concept emerged in materials biology and bioengineering discussions in the late 20th and early 21st centuries as researchers sought to describe agents that act specifically at interfaces rather than throughout a bulk phase.

Natural interfacides may arise as endogenous extracellular matrix components or serum molecules that preferentially accumulate at material boundaries. Synthetic interfacides include designed peptides, polymers, or nanoparticles engineered to present functional groups or recognition motifs at the interface, thereby directing cell adhesion, signaling, or anti-fouling properties.

Applications include improving implant integration, tuning biosensor performance, and guiding tissue regeneration. Interfacide engineering aims to reduce foreign body responses, control inflammation, and enable responsive interfaces that adapt to mechanical or chemical cues. Safety, biocompatibility, and regulatory considerations are active topics in development.

Current research seeks to standardize terminology, characterize interfacide–interface interactions across materials systems, and develop robust metrics for stability and efficacy. Some scholars caution that the concept overlaps with broader interfacial science and biomaterials terminology, and prefer more specific descriptors for individual mechanisms.