A professor of biomedical engineering from New York City’s Columbia University has developed an implantable biobot drug pump that can deliver timely doses of drugs.
The device has been tested on mice with bone cancer with highly promising results. In tests using a chemotherapy drug, the small doses delivered by the implantable biobot drug pump were more effective than delivering standard chemotherapy drug doses. Tumors grew more slowly in mice fitted with the biobot and more tumor cells were killed. Additionally, the toxic effects of the chemotherapy drugs were reduced in other areas of the body.
While the device functions in a similar manner to a wristwatch, Samuel Sia and his team did not use metal cogs for the device. Instead they 3D printed the device in hydrogel. The 15-millimeter hydrogel biobot uses two hydrogel gears which are implanted with iron nanoparticles. The gears are driven by an external magnet thus creating an accurate timing mechanism that can deliver small doses of drugs.
Each click of the gears aligns chambers in the hydrogel through which small doses of drugs flow out.
The prototype developed by Sia’s team continuously ticks, delivering a small but steady dose of a drug. However, it would not be necessary to have constant movement. The device could just as easily be activated by a physician to deliver drugs as and when necessary. All that would be required is for a magnet to be applied to the skin above the implant.
Unfortunately, the system has potential to be affected by magnetic fields. Sia’s team appreciates the flaw in the design, but is working on a new prototype that could be activated by another means: Ultrasound for example. The prototype is not the finished device, it is really just a proof of concept.
The team has yet to determine if the device would be commercially viable, although the benefits are clear. The device could be used to deliver highly targeted doses of drugs, rather than flooding the body with highly toxic compounds. The device could also potentially be used to release hormones.
The flexible biobot represents something of a breakthrough. While hard materials are ideal for this kind of device, they are far from ideal. However, making a ‘clockwork’ device out of soft materials is something of a challenge. The trick was getting the correct consistency of material that is stiff enough to function as a tiny implantable machine, while being soft and flexible enough to be compatible with bodily tissues.
To design the implantable biobot drug pump, Sia’s team first had to develop a new method of 3D printing. The new technique creates layers of hydrogel which are combined to create soft and flexible rubbery shapes. The process is not entirely automated at present. The researchers still need to manually construct the different layers, although a more automated assembly line is possible. Sia said the process is also quick. The device took around 30 minutes to construct, whereas standard 3D printing techniques would have taken several hours, if they could work on hydrogel that is.
Sia and his team have developed a number of different devices using their 3D printing technique, and while the implantable biobot drug pump may not prove to be cost-effective or practical to use, Sia says “I’m confident that we’ll find something useful.”