It has been challenging for microneedles to deliver drugs effectively to thin tissues with little background support such as the cornea. Herein, we designed a microneedle pen system, a single microneedle with a spring-loaded microneedle applicator to provide impact insertion. To firmly attach solid microneedles with 140 μm in height at the end of macro-scale applicators, a transfer molding process was employed. The fabricated microneedle pens were then applied to mouse corneas. The microneedle pens successfully delivered rhodamine dye deep enough to reach the stromal layer of the cornea with small entry only about 1000 μm2. When compared with syringes or 30G needle tips, microneedle pens could achieve more localized and minimally invasive delivery without any chances of perforation. To investigate the efficacy of microneedle pens as a way of drug delivery, sunitinib malate proven to inhibit in vitro angiogenesis, was delivered to suture-induced angiogenesis model. When compared with delivery by a 30G needle tip dipped with sunitinib malate, only delivery by microneedle pens could effectively inhibit corneal neovascularization in vivo. Microneedle pens could effectively deliver drugs to thin tissues without impairing merits of using microneedles: localized and minimally invasive delivery.
Bibliographical noteFunding Information:
This research was financially supported by research grants from the National Research Foundation of Korea (NRF) funded by the Korea government (MSIP) ( NRF-2013R1A2A2A01069228 to W. Ryu), the Korea Healthcare technology R&D Project, Ministry for Health & Welfare Affairs, Republic of Korea ( HI08C2149 to W. Ryu), the Seoul National University Research Grant ( 800-20140542 to JeH Kim), the Pioneer Research Program of NRF/MEST ( 2012-0009544 to JeH Kim), and the Bio-Signal Analysis Technology Innovation Program of NRF/MEST ( 2009-0090895 to JeH Kim).
All Science Journal Classification (ASJC) codes
- Pharmaceutical Science