Idera was always fascinated by tattoos.
He was thrilled to be given the assignment of investigating how tattooing can be used intradermally as a drug delivery method.
Lawal is a doctoral candidate from the Department of Chemical Engineering the housed in Texas Tech University’s Edward E. Whitacre Jr. College of Engineering a six-week deadline was set for the creation of a research project on intradermal drug delivery by tattoos.
“I took interest in it because I didn’t know people actually researched tattoos,” he said. “I don’t have one of my own, but I find tattoos really cool. So, I was like, ‘whoa, yeah, I’m in.’ Even after I was done with the project I continued to work on it to a point where I was able to publish a paper.”
The paper, “Visualization of drug delivery via tattooing: effect of needle reciprocating frequency and fluid properties,” was published in January and examines the underlying physics involved in the tattooing process with the aid of high-speed imaging.
Lawal shared his research with the American Physical Society in March. He also presented a video that illustrates his findings.
“In my lab, we have these high-speed cameras that slow down the process because, again, these needles are moving really, really fast,” Lawal explained. “The speeds vary from 46 injections per second to around 200 injections per second.
“In our lab, we record each injection in slow motion and we have skin models. We’re able to observe how this ink is delivered into the skin and what the mechanism is that drives it.”
Although past research had explored tattooing’s potential as an injection method for drugs, little was known about the fluid dynamics. Lawal’s research provided insight into a different method for delivering fluids that could provide a useful system for administering vaccines in the future.
The current status of vaccine delivery is that they are administered by hypodermic injection needles. These needles have hollow ends and are used to deliver vaccines.
Tattoo needles are different. A tattoo needle does not have fluid passing through it. Instead of being hollow, it is inked. And, unlike a hypodermic needle, a tattoo needle’s purpose isn’t to penetrate muscle but to puncture skin.
When the tattoo needle is pulled out, the tiny puncture area caused by the micro-injury closes and the needle’s ink fills in.
Lawal demonstrated how ink was delivered to the skin using high-speed cameras.
It’s this reaction that could lead to a medical breakthrough.
“What you have at the end of a tattoo is hundreds, maybe even thousands, of micro-injuries, from these small needles,” Lawal said. “That leads to the immune system’s inflammatory response kicking in and with that is a flood of immune cells.”
Each of the injuries to the skin attracts immune cells, such as macrophages and immune mast cells.
“Immune cells are always patrolling,” Lawal explained. “Once they find something, an imposter – which typically happens by immune cells binding to this imposter’s antigen – they can then signal for more immune cells to flood the site. This ostensibly happens at the sites of the micro-injuries and is the proposed reason for the heightened immune response.”
Lawal’s research also looked at the viscosity of the fluids being injected, an important factor for the potential uses of tattoo needles in the medical field, where DNA vaccines are typically too thick to circulate using the intramuscular method.
With tattoo needles, vaccines can be applied to a greater area using many smaller punctures. The larger application area and the response of the body’s immune system also allow for the possibility of smaller doses and fewer side effects.
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