While we've heard about a number of drug-dispensing medical implants, most of them have the same drawback – they end up getting covered in scar tissue. An experimental new one avoids that problem by changing shape as the tissue starts to form.
Ordinarily, the immune system registers an electronic implant as a foreign body, and responds by encapsulating it in scar tissue in order to isolate it. Unfortunately, that tissue clogs the ports that the device uses to deliver medication, ultimately rendering it useless.
A team of scientists from the University of Galway (Scotland) and MIT set out to change that, developing a prototype drug-delivery implant known as the FibroSensing Dynamic Soft Reservoir (FSDSR).
The soft-bodied device has a conductive porous outer membrane, through which an electrical signal continuously passes. As the pores of that membrane start getting blocked by scar tissue cells, the signal is impeded.
Integrated electronics detect that increased electrical impedance, and respond by inflating or deflating the implant. That change in shape temporarily halts the formation of scar tissue. When the tissue does start forming again, the implant simply changes shape again.
Additionally, given the fact that some scar tissue will still accumulate on the implant (partially blocking its ports), the device is able to compensate by automatically increasing the frequency and/or force of its drug-delivery actuations. Doing so allows it to ultimately maintain the same dosage.
"The technology which we have developed, by using soft robotics, advances the potential of implantable devices to be in a patient’s body for extended periods, providing long-lasting therapeutic action," said U Galway's Dr. Rachel Beatty, co-lead author of a paper on the study. "This approach could generate revolutionary changes in implantable drug delivery for a range of chronic diseases."
The paper was recently published in the journal Science Robotics.
Source: University of Galway
