Virginia Tech researchers have developed the iNal patch, a wearable microneedle device smaller than a penny that automatically detects fentanyl and delivers naloxone to reverse opioid overdoses. Designed by a team led by Wujin Sun, the patch uses fentanyl-sensitive molecular gates to release medication without requiring a bystander. In animal trials, the patch successfully reduced overdose symptoms in mice across multiple exposures. The researchers have filed a patent application for the technology.
iNal microneedle patch technology
- ▪Virginia Tech researchers Wujin Sun and Penghui Zhao filed a patent application related to the iNal patch technology.
- ▪The iNal patch is smaller than a penny and uses an array of 121 microscopic needles to reach the fluid just beneath the skin.
- ▪Researchers in Virginia Tech's Department of Biological Systems Engineering developed a wearable microneedle patch, called the iNal patch, to detect fentanyl and automatically release naloxone.
Fentanyl detection mechanism
- ▪The iNal patch contains porous silica nanoparticles loaded with naloxone, with openings covered by fentanyl-sensitive molecular gates.
- ▪When fentanyl reaches the iNal patch, it triggers the molecular gates to open and release naloxone, with higher fentanyl concentrations triggering more medication release.
Naloxone automatic release
- ▪The iNal patch is designed to retain naloxone in unopened pores to allow for repeated, automatic release if fentanyl levels remain high.
- ▪The repeated-release design of the iNal patch addresses the risk of overdose symptoms returning after an initial dose of naloxone wears off.
Laboratory testing results
- ▪In laboratory settings, the iNal patch responded to fentanyl within minutes, released larger quantities of naloxone as fentanyl concentrations increased, and continued releasing medication for up to 24 hours.
- ▪Laboratory evaluations of the iNal patch showed no significant signs of skin irritation or other harmful effects.
Animal testing results
- ▪Mice treated with the iNal patch exhibited substantially fewer opioid-induced symptoms than mice exposed to fentanyl without the patch.
- ▪In animal studies, the iNal patch successfully released more naloxone as fentanyl doses increased and responded through at least three separate fentanyl exposures in mice.
Opioid overdose harm reduction
- ▪Virginia Tech assistant professor Wujin Sun characterized the iNal patch as a harm-reduction tool rather than a replacement for pain medication or other medical care.
- ▪The iNal patch project, which began in 2022, involved collaborators from Virginia Tech, the University of Wisconsin–Madison, the University of California Riverside, and the University of Sydney.
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