Rapid Prototyping of Organ-on-a-Chip Devices Using Maskless Photolithography.

Dhanesh G Kasi,Pasqualina M Sarro,Christine L Mummery,Arn M J M Van Den Maagdenberg,Jean-Phillipe M S Frimat,Paul A Motreuil-Ragot,Valeria V Orlova,Mees N S De Graaf,Michel D Ferrari,Massimo Mastrangeli

doi:10.3390/mi13010049

Dhanesh G Kasi, Pasqualina M Sarro + Show 8 more

Open Access

https://doi.org/10.3390/mi13010049

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Abstract

Organ-on-a-chip (OoC) and microfluidic devices are conventionally produced using microfabrication procedures that require cleanrooms, silicon wafers, and photomasks. The prototyping stage often requires multiple iterations of design steps. A simplified prototyping process could therefore offer major advantages. Here, we describe a rapid and cleanroom-free microfabrication method using maskless photolithography. The approach utilizes a commercial digital micromirror device (DMD)-based setup using 375 nm UV light for backside exposure of an epoxy-based negative photoresist (SU-8) on glass coverslips. We show that microstructures of various geometries and dimensions, microgrooves, and microchannels of different heights can be fabricated. New SU-8 molds and soft lithography-based polydimethylsiloxane (PDMS) chips can thus be produced within hours. We further show that backside UV exposure and grayscale photolithography allow structures of different heights or structures with height gradients to be developed using a single-step fabrication process. Using this approach: (1) digital photomasks can be designed, projected, and quickly adjusted if needed; and (2) SU-8 molds can be fabricated without cleanroom availability, which in turn (3) reduces microfabrication time and costs and (4) expedites prototyping of new OoC devices.

Highlights

Organ-on-a-chip (OoC) is a technology that emerged from lab-on-a-chip and refers to biomimetic models built on a microfluidic chip
Since the setup is based on a digital micromirror device (DMD) connected to an inverted microscope, we opted for round glass coverslips of 130–160 μm thickness and 50 mm diameter as the substrate for SU-8
We explored the use of low-cost glass coverslips, a negative photoresist, and a commercially available DMD-based setup for maskless UV photolithography (PRIMO, Alvéole Lab)

Summary

Introduction

Organ-on-a-chip (OoC) is a technology that emerged from lab-on-a-chip and refers to biomimetic models built on a microfluidic chip. OoC models are engineered by integrating (human) cells and tissues within a microdevice that contains a single or multiple cell culture compartments or microfluidic channels, sensors, and/or valves [1,2,3]. Combined with human induced pluripotent stem cells (hiPSCs), OoC technology can be used to reveal disease mechanisms and to perform drug discovery, especially by employing patientspecific cells in combination with matched (genetically repaired) isogenic controls [4]. Organ-specific cells can be derived from hiPSCs using standardized differentiation protocols and can be cultured in specialized chips to develop human disease models [5].

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