Microneedle arrays are promising as a way to help heal wounds, administer drugs, and sense a variety of biomarkers of health and disease. Because of their tiny size and smooth surface, microneedles don’t stay put in the tissues they’re attached to and tend to fall off if not kept in place by some means. Now, engineers at Rutgers University have devised a way to integrate microneedles with backward facing barbs, the kind that fishing hooks often have, so that microneedle arrays can stay in place as long as needed. To make this possible, the team relied on 4D printing, a technique that uses 3D printing to create objects that change their shape after they’re produced. “We think our 4D-printed microneedle array will allow for more robust and sustained use of minimally invasive, pain-free and easy-to-use microneedles for delivering drugs, healing wounds, biosensing and other soft tissue applications,” said Howon Lee, the senior author of the study, in a Rutgers press release. The researchers used chicken meat to test their barbed microneedles and they showed that they grab on eighteen times stronger than identical, but barbless microneedles. Here’s some info about how the barbed microneedles are created, according to the study abstract in journal Advanced Functional Materials: …a MN [microneedle] with bioinspired backward‐facing curved barbs for enhanced tissue adhesion, manufactured by a digital light processing 3D printing technique, is presented. Backward‐facing barbs on a MN are created by desolvation‐induced deformation utilizing cross‐linking density gradient in a photocurable polymer. Barb thickness and bending curvature are controlled by printing parameters and material composition. It is demonstrated that tissue adhesion of a backward‐facing barbed MN is 18 times stronger than that of a barbless MN. Also demonstrated is sustained drug release with barbed MNs in tissue. Improved tissue adhesion of the bioinspired MN allows for more stable and robust performance for drug delivery, biofluid collection, and biosensing. Here’s a short video showing off the new barbed microneedles and how well they can grab onto chicken meat: Source
