Session: Rising Stars of Mechanical Engineering Celebration & Showcase

Paper Number: 149682

149682 - Intradermal Nanoparticles as Minimally Invasive Implants for Human Health 

Our mission is to develop nanoscale biomedical devices that integrate seamlessly and permanently into the skin, using minimally invasive implantation procedures akin to cosmetic tattooing. Ordinary tattoo pigments, which have been implanted in human skin for millenia using the simplest of tools, are nanoparticles. However, the modern tools of nanotechnology have scarcely been brought to bear on tattoo pigments, despite the widespread popularity of tattoos worldwide. The opportunity to replace tattoo pigments with functional nano-biosensors, as well as the general lack of fundamental knowledge on the safety of ordinary tattoo pigments, motivates the need for more research on the biocompatibility of nanoparticles implanted in the skin. We combine the tools of nanotechnology with various ex vivo and in vivo models to understand how to design and create skin nano-implants that are as safe, hypo-allergenic, and biocompatible as possible, and to confer new functions to the skin.

Two types of biomedical tattoos currently under investigation in our laboratory are ultraviolet-sensing and ultraviolet-protective tattoos for personal UV exposure monitoring, management, and protection. The UV-sensing tattoos comprise nano-encapsulated photochromic compounds that provide a colorimetric readout of incident UV exposure. We are able to tune the color and sensitivity of these nanosensors through structural modification of the photochromic dopants, enabling us to demonstrate intradermal colorimetric radiometers and dosimeters for UV and gamma radiation. The material cost of these nanosensors is only approximately $0.01 and they can be implanted using a non-surgical tattoo procedure in a matter of seconds with minimal pain (unlike surgical implant procedures), while the intradermal dose of material in the implant is on the order of only 1 milligram. These UV-active tattoos have been tested in living animal and human models, where we have demonstrated excellent biocompatibility and long-lasting function for months to years at least. Concurrently, we have developed an invisible tattoo containing ultra-photostable UV protectants that dissipate UV light entering the skin, permanently reducing the risk of UV-related skin cancer and aging in a single procedure. We anticipate that these intradermal implants have the potential to revolutionize the fight against a skin cancer epidemic that continues to expand despite widespread public UV protection campaigns, likely due to the limitations of topical sunscreens as short-lived, difficult-to-use, ecosystem-polluting photoprotectants.

Ongoing work aims to systematically optimize (i) the biosafety of the nanoparticles and “inks” derived thereof by investigating the effects of particle size, composition, surface chemistry, and fluid properties, and (ii) the methods of implantation to minimize acute pain and trauma by comparing needle-based and needle-free injection technologies. Extending this work into the domain of education and outreach, we also wish to share the outcomes of an ongoing art-meets-science “tattoo a fruit” workshop designed to influence participant attitudes about science, technology, and engineering.

Presenting Author: Carson Bruns University of Colorado Boulder

Presenting Author Biography: A creator of color-changing tattoo inks and shape-shifting molecular machines, chemist/artist Carson Bruns uses nanoscience to invent new materials and technologies. Dr. Bruns has co-authored more than 50 peer-reviewed scientific publications and received the National Science Foundation’s CAREER Award in 2023. He is currently an Assistant Professor of Mechanical Engineering with the ATLAS Institute at the University of Colorado Boulder, where he directs the Emergent Nanomaterials Lab.

Authors:

Carson Bruns University of Colorado Boulder