Emerging wet electrohydrodynamic approaches for versatile bioactive 3D interfaces

There is a compelling need for delicate nanomaterial design with various intricate functions and applications. Electrohydrodynamics applies electrostatic force to overcome the surface tension of a liquid jet, shrinking the jet through intrinsic jetting instability into submicron fibers or spheres, with versatility from a huge selection of materials, feasibility of extracellular matrix structure mimicry and multi-compartmentalization for tissue engineering and drug delivery. The process typically involves the collection and drying of fibers at a solid substrate, but the introduction of a liquid phase collection by replacing the solid collector with a coagulation bath can introduce a variety of new opportunities for both chemical and physical functionalizations in one single step. The so-called wet electrohydrodynamics is an emerging technique that enables a facile, homogeneous functionalization of the intrinsic large surface area of the submicron fibers/spheres. With a thorough literature sweep, we herein highlight the three main engineering features integrated through the single step wet electrospinning process in terms of creating functional biomaterials: (i) The fabrication of 3D macrostructures, (ii) in situ chemical functionalization, and (iii) tunable nano-topography. Through an emerging technique, wet electrohydrodynamics has demonstrated a great potential in interdisciplinary research for the development of functional 3D interfaces and materials with pertinent applications in all fields where secondary structured, functional surface is desired. Among these, engineered biomaterials bridging materials science with biology have already shown particular potential.