Does the mere site of someone drawing blood make you wince with imagined pain? Fear not. Researchers at the University of North Carolina have developed a way to create hollow ceramic needles so fine that patients would not feel them piercing their skin. This new polymerization technology could some day take the pain out of injections and blood draws. Clustered together on a patch, these microneedles can deliver drugs or draw blood efficiently as standard hypodermic needles.
Reported in the International Journal of Applied Ceramic Technology Jan. 2008 issue , the two-photon polymerization technique is similar to the technology used in stereo-lithography rapid prototyping, which is basically a 3-dimensional laser printer. In two-photon polymerization (2PP), near-infrared (IR) laser pulses are directed at photosensitive materials to form layers of structure.
Painless Glucose Monitoring?
Ã¢â‚¬Å“Microneedles may be integrated with micropumps and biosensors to provide autonomous sampling of blood, analysis, and drug-delivery capabilities for treatment of chronic disease,Ã¢â‚¬Â said Roger Narayan, MD, PhD and lead researcher on the project. Ã¢â‚¬Å“For example, one needle, pump and sensor unit would assay the glucose level in interstitial fluid of patients with diabetes mellitus. Another needle, pump and drug-delivery unit would deliver insulin in a continuous or programmed manner.Ã¢â‚¬Â
Creating methods to intravenously deliver drugs with minimal pain and trauma, preferably by someone without specialized medical training, has been a longtime dream of biomedical engineers.  Until recently, their most promising product had been stainless steel and titanium microneedles . These metal microneedles, though, are prone to break on impact with skin.
Using organically modified ceramic hybrid materials, these new microneedles are resistant to breakage. How many other potential uses for these can you come up with? I can think of a few, but they involve espionage, biowarfare and terrorism, not such good news.
1. A. Ovsianikov, B. Chichkov, P. Mente, N. A. Monteiro-Riviere, A. Doraiswamy, R. J. Narayan (2007)
Two Photon Polymerization of Polymer-Ceramic Hybrid Materials for Transdermal Drug Delivery
International Journal of Applied Ceramic Technology 4 (1), 2229. doi:10.1111/j.1744-7402.2007.02115.x
2. University of California – Santa Barbara. “New Mircrojet To Deliver Protein Drugs Without Needles.” ScienceDaily 9 March 2007.
3. Michel Cormier, Bonny Johnson, Mahmoud Ameri, Kofi Nyam, Luz Libiran, Dee Dee Zhang and Pete Daddona “Transdermal delivery of desmopressin using a coated microneedle array patch system” Journal of Controlled Release Volume 97, Issue 3, 7 July 2004, Pages 503-511
Hypodermic syringe image by Wellcome Images. Creative Commons license