It's a 3d World!

3d printing is rapidly becoming part of everyone's lives - even if they don't know it yet. Manufacturers of cars and aeroplanes are using more and more 3d-printed parts, speeding up the development cycle and enabling bespoke adaptations at a fraction of the former cost. In medicine and in biomedical science there are many applications and, even allowing for the media hype, some amazing developments are taking place.


A mandible marked by a maxillofacial surgeon for pre-surgical planning.

The use of 3d printing from segmented CT scans is now routine and at CUH 3d scans are used by maxillofacial surgeons to plan and prepare for complex facial reconstructive surgery. The 3d prints, hardened by cyanoacrylate, can be used for plate bending and shaping to a high degree of accuracy and the material can be drilled to confirm the location of fixation screws. The benefits include a reduction in theatre time and a more precise fit for prosthetic devices.

Going one step further, 3d printing of both metal plates and surgical implants made in a bio-compatible plastic is now a reality. The technology is very expensive, but in time, as with all technology, we are bound to see the cost drop dramatically as their use becomes routine.

Additive manufacturing can also be a useful tool in research, since almost any virtual 3d image can be converted into a printable file format. Sophisticated CT scanning techniques are being used by Cambridge University's Departments of Engineering and Medicine, with the Department of Rheumatology at CUH,  to measure cortical bone thickness at the head of the femur. Models can be printed in full colour, mapping the cortical thickness  onto an exact replica of the bone surface, or scaled down as in the example shown here.

Photo of scaled down head of femur, colour-coded to indicate bone thickness
Scaled-down model of a head of femur derived from CT-scanning with coloured mapping of cortical bone thickness.

Full-colour 3d models of biochemical structures are an elegant way of making a tangible product from virtual three-dimensional compounds. Prints can also be made from 3d cryo-electron microscopy images.


Human nuclear pore complex. Cryo electron microscopy

And so to the fantastic world of implantable organs. Despite what you may hear in the media, we are a long way from printing organs for implantation in humans, but some real progress has been made employing the same technology as an inkjet printer. We know that differentiated tissues can be cultured from stem cells. Scientists have been able to print layers of cells in tiny dots in the same way as an inkjet printer lays down microscopic dots of ink. But in order to build organic structures the stem cells must be supported in a 3d 'scaffold', which is printed layer by layer to contain the stem cells – which must be kept alive throughout the process and stimulated to develop into exactly the type of cell that is needed in every part of the organ. As fantastic as this may seem, there are plenty of people working on 3d printable organs and tissues are already being produced this way for in vitro experiments. The prospect of 3d-printed hearts, kidneys and livers is no longer entirely in the realms of science fiction.

Some current uses of 3d printing are rather more prosaic. In Media Studio we have used 3d printing to replace a belt attachment for a pager, repair the viewfinder of a professional video camera, make a door stopper, hanging clips for posters, a door sign and various other small items using our low-cost FDM (fused-deposition modelling) printer. This machine is useful for making bespoke parts and gadgets for lab equipment and every-day small repairs, designed in CAD software.

Elsewhere, FDM printing has been used to print fully-functioning prosthetic limbs for a fraction of the cost of traditional manufacturing. Printing in medical-grade silicone enables facial prosthetics to be produced rapidly and at low cost, adjusting colour to match the patient's skin. This material also offers the potential to print bespoke breast implants to order, rather than having to choose from standard shapes and sizes.

If you have a novel idea for an application for 3d printing we'd love to hear from you. Give us a call in Media Studio or come and visit our 3d printing lab on Level 1 of Addenbrooke's Hospital.