A Review of Nano/Micro/Milli Needles Fabrications for Biomedical Engineering

Abstract Needles, as some of the most widely used medical devices, have been effectively applied in human disease prevention, diagnosis, treatment, and rehabilitation. Thin 1D needle can easily penetrate cells/organs by generating highly localized stress with their sharp tips to achieve bioliquid sampling, biosensing, drug delivery, surgery, and other such applications. In this review, we provide an overview of multiscale needle fabrication techniques and their biomedical applications. Needles are classified as nanoneedles, microneedles and millineedles based on the needle diameter, and their fabrication techniques are highlighted. Nanoneedles bridge the inside and outside of cells, achieving intracellular electrical recording, biochemical sensing, and drug delivery. Microneedles penetrate the stratum corneum layer to detect biomarkers/bioelectricity in interstitial fluid and deliver drugs through the skin into the human circulatory system. Millineedles, including puncture, syringe, acupuncture and suture needles, are presented. Finally, conclusions and future perspectives for next-generation nano/micro/milli needles are discussed.