Magnetization-induced self-assembly method: Micro-needle array fabrication

Chengfeng Pan, Keyun Chen, Lelun Jiang*, Zhipeng Chen, Lei Ren, Liang Liang, Wei Yuan

Journal of Materials Processing Technology Volume 227, January 2016, Pages 251-258

原文链接：https://doi.org/10.1016/j.jmatprotec.2015.08.025

Abstract

Magnetization-induced self-assembly method (MSM) was proposed to fabricate micro-needle array (MA). Curable magnetic fluid droplet array was extruded from the holes of perforated mask and meanwhile drawn to form the MA shape by magnetic force. MA was heated and cross linking solidified. The formation mechanism of magnetization-induced self-assembly micro-needle was analyzed and its process was divided into three stages: powders magnetizing, chain and aggregation, formation of micro-needle tip, and formation of micro-needle. The formation process was observed by high-speed camera. It was found that the formation process was consistent with the theoretical analysis. The effects of mask-hole diameter, powder-to-volume ratio and magnetic field intensity on MA fabrication were investigated by experiments. The results showed that the sharpness of micro-needle decreased with the decrement of mask-hole diameter and the increment of magnetic field intensity. The height of micro-needle increased with magnetic field intensity and powder-to-volume ratio. We anticipate that MSM will be suitable to fabricate MA-substrate for biomedical engineering fields such as biosensor, bio-electrode and transdermal drug delivery.

Keywords

Micro-needle array; Magnetization-induced; Self-assembly; Magnetic fluid; Solidify