The Electrospinning Process
Electrospinning is an established method of producing nano- and micro-fibres from a wide variety of natural and synthetic polymers. A polymer solution is injected through a nozzle or needle which is charged to a high voltage. The applied voltage induces a charge on the surface of the liquid droplet and when this is sufficiently high, the hemispherical surface of the fluid elongates and a Taylor cone is established. On increasing the applied voltage further, a charged liquid jet is ejected from the Taylor cone and attracted to the earthed collector, which is positioned at a fixed distance from the needle. During this process the solvent evaporates from the polymer solution, leaving dry polymer fibres on the collector. Electrospinning with a single Taylor cone is typically low throughput but new equipment, such as multi-nozzle injectors and needle-less spinnerets, and processes are facilitating industrial scale-up.
We are experts in manufacturing processes and polymer chemistry with the know-how to precisely control important fibre parameters, such as diameter, alignment and surface texture. We aim to guarantee batch-to-batch consistency at appropriate scale.
The electrospinning process is sensitive to multiple factors, including temperature and humidity. We focus on removing variability from manufacturing processes, even as they are scaled up, and on the production of highly consistent scaffolds which are suitable for clinical applications.
We use needle-based electrospinning systems which allow high levels of precision and the fabrication of highly aligned fibres. We use sophisticated equipment with tight environmental control from different suppliers.
The quality of each scaffold batch is checked for a range of specifications including fibre diameter, pore size, porosity, thickness, mechanical properties and residual solvent.
R&D and Manufacturing workflows are segregated in a suite of ISO Class VII cleanrooms.
We are a partner in the EU funded H2020 project BIORIMA (Biomaterial Risk Management), which is developing an integrated risk management framework for nano-biomaterials (NBM) used in advanced therapeutic medicinal products and medical devices. The BIORIMA risk management framework is a structure upon which the validated tools and methods for materials, exposure, hazard and risk assessment and management are allocated plus a rationale for selecting and using them to manage and reduce the risk for NBM used in medical applications.
We participate in the working group formed to develop an ASTM Standard Guide for Characterizing Fiber‐Based Constructs. This will provide developers of tissue-engineered medical products with guidance on selecting measurements for characterizing fiber‐based scaffolds. The output of the first workshop in 2018 was published in the Journal of BioMedical Materials Research. A follow-up workshop is scheduled for May 2020.