A Facile Approach for Rapid Prototyping of Microneedle Molds, Microwells and Micro-Through-Holes in Various Substrate Materials Using CO2 Laser Drilling.

Yu-Wei Chen,Ting-Yuan Tu,Mei-Chin Chen,Kuang-Wei Wu

doi:10.3390/biomedicines8100427

Yu-Wei Chen, Ting-Yuan Tu + Show 2 more

Open Access

https://doi.org/10.3390/biomedicines8100427

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Journal: Biomedicines	Publication Date: Oct 18, 2020
Citations: 12	License type: CC BY 4.0

Affiliation: National Cheng Kung University

Abstract

CO2 laser manufacturing has served as an enabling and reliable tool for rapid and cost-effective microfabrication over the past few decades. While a wide range of industrial and biological applications have been studied, the choice of materials fabricated across various laser parameters and systems is often confounded by their complex combinations. We herein presented a unified procedure performed using percussion CO2 laser drilling with a range of laser parameters, substrate materials and various generated microstructures, enabling a variety of downstream tissue/cellular-based applications. Emphasis is placed on delineating the laser drilling effect on different biocompatible materials and proof-of-concept utilities. First, a polydimethylsiloxane (PDMS) microneedle (MN) array mold is fabricated to generate dissolvable polyvinylpyrrolidone/polyvinyl alcohol (PVP/PVA) MNs for transdermal drug delivery. Second, polystyrene (PS) microwells are optimized in a compact array for the formation of size-controlled multicellular tumor spheroids (MCTSs). Third, coverglass is perforated to form a microaperture that can be used to trap/position cells/spheroids. Fourth, the creation of through-holes in PS is validated as an accessible method to create channels that facilitate medium exchange in hanging drop arrays and as a conducive tool for the growth and drug screenings of MCTSs.

Highlights

Microfabrication techniques have revolutionized the way biologists and medical scientists conduct studies in the last few decades [1]
To investigate the effect of the laser parameters on the shape and size of the created PDMS mold, PDMS slabs were first placed at focal plane positions (FPPs) of +3, +5, or
By increasing the pulses to perforate the PS substrate, we demonstrated that laser drilling can further enable convenient convenientfluid fluidexchange exchangeduring duringthe thegrowth growthofofMCTSs

Summary

Introduction

Microfabrication techniques have revolutionized the way biologists and medical scientists conduct studies in the last few decades [1]. Microfabrication techniques have been widely applied in various areas of biomedical research, the dependence on lithographic procedures that require either chemical etching with special equipment and cleanroom facilities or a silicon master for replica molding has been criticized as a barrier to entry. Even minor changes in the design of a microstructure require a cumbersome and laborious process accompanied by Biomedicines 2020, 8, 427; doi:10.3390/biomedicines8100427 www.mdpi.com/journal/biomedicines. Most biomedical laboratories can utilize alternative commercial products with relative ease, the lack of flexibility in changing the design and protocol integration as well as the costly nature often hamper the utility of these alternatives. Identifying a rapid and economical method for the reliable generation of microstructures has become crucial, especially in terms of methods that allow for quick iterations in design modification during initial stages of validation, which is imperative for individual labs

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