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The Spinneret
Summer 2017
A ramé-hart Newsletter Covering Coaxial and Triaxial Needle Products
 

In 1995, Christopher Reeve, the actor who played Superman, fell from a horse and broke his neck becoming paralyzed from the neck down. Today, 22 years later, new methods are being developed at the University of Wollongong to facilitate nerve regeneration by artificial means - methods that could help people like Superman.¹

Pultrusion, a process that is similar to extrusion but in which the material is pulled instead of pushed, combined with electrospinning is used to produce artificial nerve conduits. This biofabrication process is able to produce via electrical stimulation filaments that are drug-laden, biocompatible, mechanically robust and sufficiently biodegradable. It's no small task to design artificial nerve conduits that meet these requirements, mimic natural tissue, facilitate neurotropic and neurotrphobic communication, promote axonal nerve regrowth, and in general, foster the repair of sensitive nerve tissue.

To offer a variety of conduit structures, various ramé-hart spinnerets were used.² Coaxial, triaxial, and custom coaxial multi-lumen designs with four, five, or more inner needle components were used.

Custom Coaxial Multi-Lumen Spinneret with 16 Inner Needle Components

In the Wollongong study, various spinneret designs were used. The external material used was a hydrogel which was extruded through the outer needle. The multiple inner needles were used to produce filaments. Design variables for the spinnerets include: number of inner needles, spacing between inner needles, inner needle gauge (diameter), outer needle gauge (diameter). Variables that drive the design are: number of desired filaments, extrusion speed, and viscosity of the hydrogel. With higher viscosity hydrogels, for example, greater spacing between the inner needle components is required.

By controlling spinneret design parameters, researchers are able to build fibrous structures that feature a wide variety of filaments within. By altering parameters, it's possible to control the number of filaments, their size and structure, and their structural properties. This flexibility allows for the design and fabrication of optimal nerve conduit. These methods could also be applied to other bioengineering  tasks such as regenerative tissue, artificial muscle, and biomicrofluidics.

If your application requires a configuration that falls outside of what can be configured using our Custom Coaxial Needle Worksheet, please contact us so we can work up a design that meets your requirements.

¹ Schirmer, K. S. U ., Gorkin III, R., Beirne, S., Stewart, E., Thompson, B. C., Quigley, A. F., Kapsa, R. M. I. & Wallace, G. G. (2016). Cell compatible encapsulation of filaments into 3D hydrogels. Biofabrication, 8 (2), 025013-1-025013-13. Available here: https://tinyurl.com/yc8moyyr.

² See Table 2 on page 16 of the above reference paper.
 

Back by popular demand, we offer coupon code CUSTOM25 which you can use during checkout the next time you purchase a custom coaxial needle. Click on coupon to go to ordering page.

Please visit our website at www.customspinnerets.com to check out all of our prebuilt and custom coaxial and triaxial spinnerets. Thank you for your business. Please contact us if you have any questions or need something special.

Regards,

Carl Clegg
Director of Sales
Phone 973-448-0305
www.customspinnerets.com
www.ramehart.com
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