A honeybee stinger inspired self-interlocking microneedle patch and its application in myocardial infarction treatment

Microneedle patches are widely employed in pain-free drug delivery, biosensing, and cosmetic applications. However, weak tissue adhesion remains a major challenge in clinical translation of microneedle patches. Here, mimicking the structural features of honeybee stingers, stiff polymeric microneedles with unidirectionally backward facing barbs were fabricated and embedded into various elastomer films to produce self-interlocking microneedle patches. The spirality of the barbing pattern was adjusted to increase interlocking efficiency. In the challenging working condition of animal hearts beat with large cyclic strains, the barbs provided 0.4 N interlocking force, which resulted in firm fixation of the bioinspired microneedle patch. In addition, the minimal bleeding caused by microneedle puncturing adhered the porous surface of the patch substrate between microneedles to the epicardium via coagulation. In the demonstrative application of myocardial infarction treatment, the microneedle patches significantly reduced cardiac wall stress and strain in the infarct and border zone, maintaining left ventricular function and morphology. In addition, the microneedle patch was minimally invasively implanted onto beating porcine heart free of sutures and adhesives, and the fixation step only took 2 minutes. Therefore, the honeybee stinger inspired microneedles could provide an adaptive and convenient means to adhere patches for various medical applications. Examination of the transcriptomes of rat heart tissue samples with the treatment below(n=6 MI,n=6,Sutured patch,n=6 Microneedle patch,n=6 Sham)