Direct 3D printing of two-component silicone

Summary

 

The system being developed by a team led by a King’s College London researcher is unique in its ability to 3D print a biocompatible two-part silicone required for medical devices such as facial/body prostheses. Silicone formulations have been developed and printed using a modified 3D printer with a custom print head to print room-temperature curing silicone objects with properties similar to those required for prostheses.

 

What

 

A 3D printing system (including a mixing print head, silicone “ink” formulations and associated control software) has been developed that will directly print patient specific body/facial prostheses using digital images of the defect. The innovation is expected to significantly reduce the time taken to make prostheses and also reduce the number of clinical appointments and provide a more reliable result. It will achieve better reproducibility and is expected to allow a better match to the patient’s skin colour and texture than is presently achievable making the prosthesis less noticeable.

 

 

Why

 

Facial/body prostheses are often required for patients who have lost facial/body parts, such as an ear, nose, eye, finger, hand or breast or combinations of these. These defects can result from trauma, congenital malformations or diseases such as cancer. Improvements in medicine, surgical techniques and in particular cancer survival rates are resulting in increasing numbers of patients who require prostheses.

 

 

Benefits

Typically, facial/body prostheses are manufactured by a lengthy multi-step process that involves taking an impression from the patient, hand carving the missing defect, creating a two or three part stone mould into which pigmented silicone is placed, colour matched to the surrounding tissue. These methods of prosthesis construction are time-consuming, involving five to six patient visits and results are dependent on the skills of the prosthetist.

 

Opportunity

 

The ability to 3D print biocompatible silicone presents a number of potentially significant product opportunities. The greatest of these include patient-specific devices, such as:

•       body surface prostheses to replace missing non-articulated body parts (nose, ear, cheek, breast etc.);

•       coverings for prosthetic limbs;

•       anatomical models to enable surgeons to improve pre-operative planning, simulation and teaching prior to complex surgical procedures (e.g. correcting congenital abnormalities or reconstructing following trauma);

•       custom fingers for advanced soft robotics; or

•       biocompatible in vivo medical devices or medical device components, where advanced silicones or variable hardness would be appropriate.

 

Figure 1: A side view of the 3D printer head according to one embodiment of the invention

 

 

The Science

 

Dr Coward, a Reader in Maxillofacial and Craniofacial Rehabilitation at King’s, was motivated to develop the technology by the desire to produce directly silicone prosthetic objects from medical images.  Funding for the invention and some subsequent development was provided by Dstl, the UK Ministry of Defence’s research agency, with the aim of improving treatment options for trauma victims. Collaborators in the invention were Dr Jim Smay of Oklahoma State University (responsible for the design of the mixing print head for silicone printing and its control software) and Prof Mark Waters of Technovent Ltd (developing suitable biocompatible room-temperature curing silicone formulations).  Prof Waters and Dr Coward continue to collaborate on refinement of the technology.

 

Opportunity

 

Initially, the collaborators are seeking partners wishing to further develop and commercialise the technology for supplying prostheses.  This could be through and hardware and consumables supply model or via a service provision model.  The IP owners are also open to licensing the technology for application to other fields, and are willing to grant options and evaluation licences. Field exclusivity is possible for suitable partners.

 

 

IP Status

 

Priority patent applications were filed in the USA, with the earlier dated 14 Jan 2014.  An International PCT application (with Application Number PCT/GB2015/050056) was filed on 13 Jan 2015 and this has been followed by national filings at the US and European patent offices.

Copyright exists in the hardware design drawings, the control software and documentation.

 

Patent Information:
For Information, Contact:
Ceri Mathews
IP & Licensing Manager
King's College London
ceri.mathews@kcl.ac.uk
Inventors:
Trevor Coward
Jim Smay
Swati Jindal
Mark Waters
Keywords: