Amid a U.S. opioid crisis, a team from Virginia Tech's Department of Biological Systems Engineering has developed a tiny patch that could one day save the lives of people experiencing a fentanyl overdose, even in the absence of a witness or someone to help.

The wearable microneedle patch, dubbed the iNal patch, can detect fentanyl in the body and automatically deliver naloxone when it senses the drug. Because naloxone can reverse an opioid overdose, the technology could offer a lifesaving intervention without requiring someone else to be present to administer the nasal spray or injection, which are some of the current solutions for responding to fentanyl overdose.

Source: Penghui Zhao

The iNal patch achieves this with an array of 121 microscopic needles that penetrate the skin to reach the fluid just beneath but without incurring much, if any, tissue damage.

The patch contains porous silica nanoparticles loaded with naloxone. Each nanoparticle is enveloped by fentanyl-sensitive molecular gates that open when the drug is detected, enabling naloxone to be released into the body. The system is designed to respond to higher fentanyl concentrations by releasing larger amounts of naloxone. By releasing the medication in controlled doses, the patch can conserve the remaining naloxone for subsequent doses if needed.

This is an important feature since fentanyl can remain active longer than naloxone. As the initial dose wears off, overdose symptoms might return, prompting the patch to detect persistent, elevated fentanyl levels and then release additional naloxone as needed.

In the lab, the patch released naloxone when it detected fentanyl in a matter of minutes. Mice treated with the patch also showed far fewer opioid-induced symptoms than the mice exposed to fentanyl without the patch, the team discovered.

The team suggests that while they developed the patch with fentanyl and naloxone in mind, they believe the system could be modified to recognize other opioids or release other drugs that block their effects.

An article detailing the patch, “A Fentanyl‐Responsive Microneedle Patch for Harm Reduction,” appears in the journal Advanced Science.