High-voltage jets spin polymer solution into nanofiber meshes that mimic native ECM
Electrospinning begins with a spinnable polymer solution held at a syringe tip and subjected to a strong electric field, priming it for jet formation.
A polymer such as poly(caprolactone) (PCL), poly(lactic-co-glycolic acid) (PLGA), collagen, gelatin, or silk fibroin is dissolved in a volatile solvent at a concentration high enough to entangle polymer chains — a prerequisite for forming continuous fibers rather than droplets (electrospraying).
A high-voltage power supply (10–30 kV) connects to the needle or the solution itself, while the collector is grounded. The resulting electric field induces a net charge on the pendant droplet at the needle tip, held there by surface tension and the syringe pump's steady flow.
Electrostatic repulsion within the droplet grows until it overwhelms surface tension, reshaping the droplet into a cone and launching a jet from its tip.
As voltage increases, the mutually repulsive charges on the droplet surface exert an outward electrostatic force that competes with the inward pull of surface tension. Past a critical voltage this balance breaks, deforming the hemispherical droplet into a sharp, conical point known as the Taylor cone.
A fine, charged jet erupts from the Taylor cone apex and accelerates toward the grounded collector, driven by the field. In this initial segment the jet travels in a straight, stable line before instabilities take over.
A rapid, chaotic whipping motion stretches the jet by orders of magnitude, thinning it from microns down to nanometers as the solvent flashes off.
Small perturbations in the straight jet segment grow explosively into a fast, looping whipping motion. Each loop stretches the jet further, and the loops themselves generate smaller sub-loops in a self-similar cascade, multiplying the total path length the jet travels before landing.
The enormous increase in surface area during whipping accelerates solvent evaporation. By the time the jet reaches the collector, most of the solvent has left and the polymer has solidified into a continuous solid nanofiber.
The collector's shape and motion determine whether fibers land as a random tangled mesh or as parallel, mechanically anisotropic bundles.
| Product | Indication | Trial Design | Key Result |
|---|---|---|---|
| Random Mesh (Static Plate) | Isotropic scaffolds | Chaotic jet lands on a stationary grounded plate with no directional bias | Mimics skin and general soft-tissue ECM; simple, low-cost setup |
| Aligned (Rotating Mandrel) | Anisotropic scaffolds | High-speed drum (1,000–10,000 RPM) captures fibers faster than they can whip freely, stretching them along the tangential direction | Directional strength and cell guidance for tendon, ligament, nerve conduits |
| Coaxial Core-Shell | Drug-loaded fibers | Two concentric nozzles co-spin a core solution (e.g. drug/growth factor) inside a shell polymer | Sustained, protected release of bioactive payloads from the fiber core |
| Melt Electrowriting | Precision microfilaments | Molten polymer jet is stabilized (no whipping) and deposited via computer-controlled XY stage | Highly ordered, reproducible micro-scale patterns for load-bearing scaffolds |
The finished nanofiber mat combines high surface area, tunable porosity, and — when aligned — directional mechanics that actively guide cell behavior.
Because nanofiber diameters (tens to hundreds of nanometers) fall within the same range as native collagen fibrils, cells seeded on the mesh encounter a topography and surface curvature close to their natural ECM environment, promoting attachment and spreading.
Random meshes provide isotropic mechanical support suited to skin and generic soft tissue. Aligned meshes provide anisotropic tensile strength along one axis and physically channel cell migration and elongation along that axis — critical for regenerating directional tissues like tendon, ligament, and peripheral nerve.