Characterization of 3D-Printed Moulds for Soft Lithography of Millifluidic Devices

Abstract

Increased demand for inexpensive and rapid prototyping methods for micro- and millifluidic lab-on-a-chip (LOC) devices has stimulated considerable interest in alternative cost-effective fabrication techniques. Additive manufacturing (AM)—also called three-dimensional (3D) printing—provides an attractive alternative to conventional fabrication techniques. AM has been used to produce LOC master moulds from which positive replicas are made using soft-lithography and a biocompatible elastomer, poly(dimethylsiloxane) (PDMS). Here we characterize moulds made using two AM methods—stereolithography (SLA) and material-jetting (MJ)—and the positive replicas produced by soft lithography and PDMS moulding. The results showed that SLA, more than MJ, produced finer part resolution and finer tuning of feature geometry. Furthermore, as assessed by zebrafish (Danio rerio) biotoxicity tests, there was no toxicity observed in SLA and MJ moulded PDMS replicas. We conclude that SLA, utilizing commercially available printers and resins, combined with PDMS soft-lithography, is a simple and easily accessible technique that lends its self particularly well to the fabrication of biocompatible millifluidic devices, highly suited to the in-situ analysis of small model organisms.

Rapid Fabrication of Chip‐Based Physiometers for Neurobehavioral Toxicity Assays Using Rotifers Brachionus calyciflorus

“…Briefly, a mixture of elastomer base and curing agent (10:1 ratio w/w) was degassed to remove any residual air bubbles and poured on an SU‐8 relief pattern to achieve a device thickness of 3–5 mm. PDMS was thermally cured at 70°C for 2 h . Cured PDMS devices were bonded to a standard borosilicate glass microscope slide via oxygen plasma surface activation and interfaced with peristaltic pumps using standard microfluidic interconnects.…”

“…Moreover, laser ablation and machining of polymers such as PMMA is prone to cracking and chipping during milling resulting in prototypes with much higher surface roughness than other approaches. More recently additive manufacturing (AM) and in particular stereolithography (SLA) technology has been proposed as an innovative technique to advance prototyping of chip‐based devices with high aspect ratios . However, several most recent studies have identified that significant amounts of toxic photoinitiator residues may leach from proprietary AM materials .…”

“…These studies highlight a potential obstacle in the use of proprietary AM resins for fabricating LOC devices intended for biological applications . Furthermore the resolution of features achieved by the market‐dominant SLA machines (approximately >100 μm) makes them only suitable to fabrication of millifluidic LOC devices channel cross‐section dimensions ranging from 250 to 2,000 μm .…”

Studying the polymerization efficiency of photosensitive compositions by using the surface plasmon resonance method

“…The free radicals migrate from one monomer to another in the course of chain growth. Radical polymerization stops, when two radicals, or creating polymer chains, or fragments of initiators combine [3]. PC can contain several photoinitiators, which enables to simultaneously enhance the efficiency of polymerization.…”

Robust Tracking of a Cost-Effective Micro-Stereolithography System Based on a Compliant Nanomanipulator

“…Among AM technologies, stereolithography (SL) and micro-stereolithography (MSL) [1,2,3] (i.e., SL in micro-scale) are widely utilized in many domains, owing to the high resolution, precision, and adaptability of the increasing number of materials. Specifically, these developments enable the precise fabrication of biomaterial scaffold [4], bioprinting [5], and microfluidic devices [6]. With the advance of MSL, more stringent fabrication demands are posed.…”