Updated: Feb 12, 2021
Key to the health and social care's sustainability plans, is the ability to make incremental changes and maintain what works best. Bioplastic has several advantages here and the missing piece of sterilisation is probably staring you in the face at break time
In care, the advent of additive manufacturing coincides with the removal of single use plastics and brings with it questions about cleaning and sterility of in-house manufactured equipment. If I can make a device on-site, how do I ensure it is as sterile as those made in classical manufacturing units? What does this do for sterilisation needs? And does the use of recycled plastics expose patients and care workers, to unexpected risks?
Recently, a team of maxillofacial surgeons at the department of Oral and Maxillofacial Surgery at Brussels' ULB, carried out sterilisation research on genioplasty guides made from PLA and PETG, using a J&J STERRAD® 100S.
The results were promising. In all cases, there was minimal acceptable deformation (under 0.2mm) and it gave the green light to the use of 3D printed equipment in reconstructive maxillofacial and dental surgery.
Yet, unlike their hospital counterparts, most of the UK's primary care, pharmacy and residential environments lack expensive sterilisers. So how could they cope with sterilising these bioplastics?
The Answer: Warm Soup
Luckily, sterilisation and infection control is a robust, well understood topic, incorporating both wet and dry sterilisation methods. Yet, a clue lies in one of the more ubiquitous, but strange areas of most UK households. Our kitchens.
As well as heating the nation's favourite ready-meals, microwaves have been a staple of medical and post-natal dry, wet and steam sterilisation for a several years. Microwaves use a powerful electromagnetic device called a magnetron, to vibrate water molecules, or any other "poled" substance, including bacteria. Microbes exposed to microwave radiation are heated from the inside out and disintegrate. Leaving intact, items they lived on.
Because of their ability to sterilise dry items, microwaves became an ideal substitute for expensive sterilisation units. Especially in waste recycling.
It doesn't stop there. Families also have access to cold water sterilisation systems from companies like Milton. A veteran of baby-care that has been around far longer than I have. With home sterilisation products from as little as £10.50.
Together with platforms like Automedi, this introduces the tantalising prospect of lowering the cost of sterilisation in primary care, while introducing climate friendly, recyclable polymer substitutes into the NHS. A key way health and social care services can reduce oil based plastic consumption, where it must still use plastics. Venepuncture can't use stainless steel, card or bamboo substitutes for PVC tubing. Bioplastics offer a way to solve this impasse, as long as they can be sterilised.
Being able to still use existing infrastructure is a key facet in keeping transformation effort and costs down, while maintaining an effective service.
3D printing: Intrinsically Sterility
3D printed bioplastics are formed at 200C and recycling uses re-extrusion at between 250 and 450 degrees Celsius. The hottest bacterial and single cell organism that can survive in nature, perishes after 113 degrees Celsius. So there is little chance the machine can maintain existing bacterial contaminants all the way from manufacture, to re-extrusion.
But the process of "Remanufacturing" care products from older care products, is key to circular health economies. Ensuring they can be sterilised pre and post-[re]manufacture.
In the hut, we have carried out a number of tests for residential, health and social care settings:
• Home – Dishwasher (low temperature cleans) + washing machine (<50C)
• Microwave – with a separate cup of water to absorb excess microwaves.
• Cold Sterilisation – e.g. Milton home steriliser (yet to finish the write-up)
Key to Automedi's ethos is Occam's Razor. Sterilisation is a crucial infrastructure in the movement towards Net Zero. The more of the existing process you can use, the better it is for adoption, costs and the planet.
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