Fabrication of a Ti porous microneedle array by metal injection molding for transdermal drug delivery

• Published in: PloS one Vol. 12; no. 2; p. e0172043
• Main Authors: Li, Jiyu, Liu, Bin, Zhou, Yingying, Chen, Zhipeng, Jiang, Lelun, Yuan, Wei, Liang, Liang
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.02.2017; Public Library of Science (PLoS)
• Subjects: Adult; Animals; Biocompatibility; Biology and Life Sciences; Calcein; Drug delivery; Drug delivery systems; Engineering and Technology; Fabrication; Fluoresceins - administration & dosage; Forearm; Health risks; Humans; Hypodermic needles; Injection; Injection molded metals; Injection molding; Injections, Intradermal - instrumentation; Injections, Intradermal - methods; Iontophoresis; Mass production; Medicine and Health Sciences; Metals; Microneedle drug delivery; Microtechnology - methods; Molding (process); Needles; Pain; Physical Sciences; Porosity; Rabbits; Research and Analysis Methods; Rhodamine; Risk reduction; Sensors; Sintering (powder metallurgy); Skin; Surgical implants; Technology application; Titanium; Transdermal medication; Trauma; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0172043

Microneedle arrays (MA) have been extensively investigated in recent decades for transdermal drug delivery due to their pain-free delivery, minimal skin trauma, and reduced risk of infection. However, porous MA received relatively less attention due to their complex fabrication process and ease of fracturing. Here, we present a titanium porous microneedle array (TPMA) fabricated by modified metal injection molding (MIM) technology. The sintering process is simple and suitable for mass production. TPMA was sintered at a sintering temperature of 1250°C for 2 h. The porosity of TPMA was approximately 30.1% and its average pore diameter was about 1.3 μm. The elements distributed on the surface of TPMA were only Ti and O, which may guarantee the biocompatibility of TPMA. TPMA could easily penetrate the skin of a human forearm without fracture. TPMA could diffuse dry Rhodamine B stored in micropores into rabbit skin. The cumulative permeated flux of calcein across TPMA with punctured skin was 27 times greater than that across intact skin. Thus, TPMA can continually and efficiently deliver a liquid drug through open micropores in skin.