Thumb-sized 3D-Printed cymbal microneedle array (CyMA) for enhanced transdermal drug delivery

Transdermal drug delivery presents a compelling alternative to both needle injection and oral ingestion of medication, as it enhances patient adherence and convenience through its non-invasive and painless administration method. The use of microneedles penetrates the barrier of the stratum corneum, facilitating the sustained delivery of drugs across the skin. However, their efficacy has been limited by the slow diffusion of molecules and often requires external triggers. Herein, a lightweight and minimized 3D-printed microneedle array is introduced, employing a cymbal-type ultrasound transducer, as the external engine for deeper and faster transdermal drug delivery. A theoretical finite element model was developed and the optimization design was conducted for structural parameters. The optimized assembled prototype was fabricated using high-precision 3D printing and weighs only 20 g. In vivo experiments using a diabetic mouse model demonstrate that local Insulin delivery with CyMA achieves systemic effects comparable to intraperitoneal administration. Such compact and effective microneedle delivery technology offers considerable promise therapeutic applications on the skin and intraoral use.

Drug delivery; Insulin; Microneedles; Sonophoresis; Ultrasound transducer.