Skip to main content
European Commission logo print header

A new concept for the hardening of polymers allowing the production of disposable surgical blades preventing the need for sterilisation (DISBLADE)

Final Report Summary - DISBLADE (A new concept for the hardening of polymers allowing the production of disposable surgical blades preventing the need for sterilisation)

The overall objective of the DISBLADE project was to produce a process for the manufacture of disposable polymer surgical blades. This relies on greatly enhancing the scientific understanding of super critical carbon dioxide (CO2) in combination with Sol-gel chemistry to enable the development of a polymer surface treatment that can dramatically increase the surface hardness of polymers to a value of at least 7 Mohs.

To meet this the team had a number of technological objectives, these were:
- produce a polymer blade with a surface hardness of at least 7 Mohs, 40 % greater than existing grades of stainless steel used for surgical blades;
- produce a blade surface hardness of at least 5 Mohs to a depth of at least 15 microns;
- achieve blade stiffness comparable to existing stainless steel blades;
- achieve a flatness tolerance of +-5 microns over the length of the polymer blade;
- have the ability to produce a blade that can cost effectively be sharpened to a level of sharpness (edge radius of less 150 nano metres) comparable to existing stainless steel blades and conform to the relevant sections in BS 2982:1992;
- achieve a level of wear resistance to enable the blade to retain its sharpness for at least as long as stainless steel blades;
- design a manufacturing cell with the ability to run 24 hours per day, 365 days per year with no more than 5% down time (including routine maintenance);
- Achieve a manufacturing cost of less than EUR 0.25 for a surgical scalpel, complete with handle and sterile packaging.
- achieve a hot plate disposal route that renders the blade sharp safe (blade edge radius is greater than 0.5 mm) in less than one second.

The project was structured into 6 work packages (WPs), as follows:
WP1: the enhancement of scientific understanding of ScCO2 and alkoxide reagents;
WP2: creation of a new technological capability to injection mould sharp features;
WP3: validation of the novel surface modification treatment;
WP4: integration & clinical trials;
WP5: innovation related activities;
WP6: consortium management.

The project yielded the following exploitable results and achievements:

-1. A method for hardening surface of polymers and blends;
-batch process for the surface hardening of polymers and polymer blends has been developed by the DISBLADE consortium, and a patent application has been filed.
This technology produces an increase in surface hardness of moulded parts, giving improved scratch resistance and allowing a sharp edge to be polished. The hardening method includes softening the polymer surface using carbon dioxide, then incorporating a ceramic pre-curser into the component. The pre-curser is then reacted to form a ceramic-polymer hybrid surface. The process is performed in a specially designed pressure vessel to which carbon dioxide and tetra-ethoxy-silane (TEOS) are added at an elevated temperature and pressure. The use of water and acidic and basic conditions aids the reaction stages to form the hard polymerceramic hybrid. The hardened polymers formed could be sharpened and used for a variety of applications, including scalpel blades and lancets, and will be taken to market initially through Rosti A/S.
The CO2-enabled Solgel surface hardening technology for polymers and blends, for example liquid crystal polymer (LCP) with 10% polyamide 6 (PA6), developed during the project can produce a surface treatment on LCP that increases the surface hardness properties of the material. This could be exploited through the production and sale of all-polymer surgical scalpels and similar medical devices to health authorities and directly to health practitioners. Clinipart, the exploitation manager, own all Intellectual property rights (IPR) and manage the exploitation for the benefit of the consortium. It is planned that these medical devices will be marketed through Rosti with the consortium forming a commercial supply chain for the design and production equipment. It is anticipated that the conservative nature of the medical industry will need to be overcome before there is wide uptake of new instruments and suitable medical testing and approval will be required.

The technology that has been developed during the project can be exploited through the production and sale of other items, for example personal care products and engineering components. Markets for these hardened surfaces in personal care products have already been investigated, and significant interest has been shown by some household name firms who cannot be named at this time. The link to these companies has been through Rosti, and Rosti will continue to form the route to market where it fits with their business. For markets outside the interest of the consortium, the patent protected intellectual property can be licensed to interested third parties. The developed knowledge, now protected by a patent application, will also be widely disseminated, and a number of publications have also been made, based on 2 initial press releases and exhibition presentations. To date, an initial patent search has not identified any patents which this technology infringes, or any prior art that would prevent a patent being issued, although clarification of the claims and description of the patent will be part of the continuing patent application procedure once the official searches have been performed.

2: All-polymer scalpel design
A design for a scalpel handle and blade set has been produced. This is optimised for the properties of the polymers and allows for the reduced flexural modulus, for example, in comparison to steel whilst being designed for final shape manufacture by injection moulding, ignoring the limitations traditionally imposed by the sheet nature of the steel blade material. The designs have been prototyped to enable ergonomic feedback to be gathered from surgical and nursing personnel before European medical device directive and FDA approval is sought and scalpels are taken to market through Rosti A/S.
The all-polymer disposable scalpel design and disposal system allows the scalpel blade to be destroyed in the operating theatre significantly reducing the risk of contaminated sharps injuries, and providing a significant social impact. This is enabled by the hardening treatment for LCP which allows a polymer blade to be produced. The scalpel design incorporates a non-removable blade and a curved blade design that would be unsuitable for conventional metal manufacturing techniques. The handle has also been ergonomically designed.
This design can be exploited through the production and sale of all-polymer surgical scalpels and similar medical devices to health authorities and directly to health practitioners. It is anticipated that these will be marketed through Rosti with the consortium forming a commercial supply chain for the design and production equipment for these and related devices. It is anticipated that the conservative nature of the medical industry will need to be overcome before there is wide uptake of new instruments and suitable medical testing and approval will be required.
The design and concept, once protected as a registered design, can also be disseminated. To date, a preliminary search of registered designs and patents has identified no areas of potential infringement.

3: Treatment equipment design
A pressure vessel and control system has been designed, built and tested to allow the surface of polymers and polymer blend components to be hardened using the process developed during the DISBLADE project. The vessel is fabricated from stainless steel with a composition chosen to withstand the reagents used in the hardening process. It contains a complex arrangement of valves and controls which allow carbon dioxide to be heated and pressurised, and other reagents to be added to the pressurised vessel. The controls are manual, to aid experimentation, but will be automated for full scale production. The temperature, pressure and flow monitors allow the process conditions to be recorded, assisting with product quality control.

The pressure vessel equipment that has been designed for the treatment of plastics using CO2 can be manufactured and sold by Fedegari to expand their pressure vessel output into new markets. Their new customers will be throughout the polymer industry, for treatment of plastics either under a technology licence from the consortium or for processes that are beyond the scope of the intellectual property of this project. Preliminary patent searches indicate that this will not infringe any existing IPR. The knowledge, once patent protected, can also be disseminated.