Fabrication of Hollow Metal Microneedle Arrays Using a Molding and Electroplating Method
- PDF / 1,239,389 Bytes
- 10 Pages / 432 x 648 pts Page_size
- 15 Downloads / 202 Views
MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.147
Fabrication of Hollow Metal Microneedle Arrays Using a Molding and Electroplating Method Philip R Miller1, Matthew Moorman1, Ryan D Boehm4, Steven Wolfley1, Victor Chavez1, Justin T. Baca2,3, Carlee Ashley, Igal Brener1, Roger J Narayan4*, Ronen Polsky1* 1
Sandia National Laboratories, Albuquerque, New Mexico 87185, U.S.A.
2
University of New Mexico School of Medicine, Albuquerque, NM, 87131, U.S.A.
3
Department of Emergency Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, U.S.A.
4 Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, North Carolina 27695-7115, U.S.A.
ABSTRACT:
The need for hollow microneedle arrays is important for both drug delivery and wearable sensor applications; however, their fabrication poses many challenges. Hollow metal microneedle arrays residing on a flexible metal foil substrate were created by combining additive manufacturing, micromolding, and electroplating approaches in a process we refer to as electromolding. A solid microneedle with inward facing ledge was fabricated with a two photon polymerization (2PP) system utilizing laser direct write (LDW) and then molded with polydimethylsiloxane. These molds were then coated with a seed layer of Ti/Au and subsequently electroplated with pulsed deposition to create hollow microneedles. An inward facing ledge provided a physical blocking platform to restrict deposition of the metal seed layer for creation of the microneedle bore. Various ledge sizes were tested and showed that the resulting seed layer void could be controlled via the ledge length. Mechanical properties of the PDMS mold was adjusted via the precursor ratio to create a more ductile mold that eliminated tip damage to the microneedles upon removal from the molds. Master structures were capable of being molded numerous times and molds were able to be reused. SEM/EDX analysis showed that trace amounts of the PDMS mold were transferred to the metal microneedle upon removal. The microneedle substrate showed a degree of flexibility that
Downloaded from https://www.cambridge.org/core. University of Cambridge, on 18 Mar 2019 at 09:34:12, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2019.147
withstood over 100 cycles of bending from side to side without damaging. Microneedles were tested for their fracture strength and were capable of puncturing porcine skin and injecting a dye.
INTRODUCTION: Microneedle technology offers an appealing alternative to hypodermic needles for interactions with tissue underneath the stratum corneum layer of the skin [1,2]. Initially developed for drug delivery, microneedles have recently become an attractive means for transdermal sensing of biomarkers due to their ability to acquire interstitial fluid in a minimally invasive manner [3, 4]. A variety of microneedle designs have been developed over th
Data Loading...
