Bioinspired 4D Transdermal Microneedles for the advanced drug delivery: Current status and future prospects

Abstract

Due to the invasive nature, the hypodermic needles cause pain and damage to the tissues. So, microneedles (MN) are a good alternative to hypodermic needles because of it’s non-invasive, negligible pain and easy‐to‐administer nature. But, sometimes MN is associated with certain drawbacks such as the risk of being broken or bent and, the fragments can cause complications, low adhesiveness, less biocompatible. To overcome the limitations of previous MNs, microscopic structures with high tissue adhesion of living entities in nature give the inspiration to fabricate bioinspired MNs. For developing this type of complex shape-altering MNs, 4D printing technology and, smart materials are very important. 4D printed objects are programmed to change shapes along with time. These objects are made up of smart and responsive materials which evolve its shape, property, and functionality with time when it is exposed to the predetermined stimulus. So this review aims to study the alteration of different smart and bioinspired materials along with different stimuli, the use of 4D printing technology in the fabrication process of bioinspired MNs.