“Biocompatible near-infrared quantum dots delivered to the skin by microneedle patches record vaccination
Kevin J. McHugh1*†, Lihong Jing1,2*, Sean Y. Severt1, Mache Cruz1, Morteza Sarmadi1,3, Hapuarachchige Surangi N. Jayawardena1‡, Collin F. Perkinson4, Fridrik Larusson5,
Sviatlana Rose1, Stephanie Tomasic1, Tyler Graf1, Stephany Y. Tzeng1§, James L. Sugarman1, Daniel Vlasic6, Matthew Peters5, Nels Peterson5, Lowell Wood5, Wen Tang1, Jihyeon Yeom1,
Joe Collins1, Philip A. Welkhoff7, Ari Karchin5, Megan Tse1, Mingyuan Gao2, Moungi G. Bawendi4, Robert Langer1||, Ana Jaklenec1
Accurate medical recordkeeping is a major challenge in many low-resource settings where well-maintained centralized databases do not exist, contributing to 1.5 million vaccine-preventable deaths annually. Here, we present an approach to encode medical history on a patient using the spatial distribution of biocompatible, near-infrared quantum dots (NIR QDs) in the dermis. QDs are invisible to the naked eye yet detectable when exposed to NIR light. QDs with a copper indium selenide core and aluminum-doped zinc sulfide shell were tuned to emit in the NIR spectrum by controlling stoichiometry and shelling time. The formulation showing the greatest resistance to photobleaching after simulated sunlight exposure (5-year equivalence) through pigmented human skin was encapsulated in microparticles for use in vivo. In parallel, microneedle geometry was optimized in silico and validated ex vivo using porcine and synthetic human skin. QD-containing microparticles were then embedded in dissolvable microneedles and administered to rats with or without a vaccine. Longitudinal in vivo imaging using a smartphone adapted to detect NIR light demonstrated that microneedle-delivered QD patterns remained bright and could be accurately identified using a machine learning algorithm 9 months after application. In addition, codelivery with inactivated poliovirus vaccine produced neutralizing antibody titers above the threshold considered protective. These findings suggest that intradermal QDs can be used to reliably encode information and can be delivered with a vaccine, which may be particularly valuable in the developing world and open up new avenues for decentralized data storage and biosensing.” (emphasis added)
