Fabrication routes via projection stereolithography for 3D-printing of microfluidic geometries for nucleic acid amplification

Charalampos Tzivelekis; Pavlos Sgardelis; Kevin Waldron; Richard Whalley; Dehong Huo; Kenny Dalgarno

doi:10.1371/journal.pone.0240237

Fabrication routes via projection stereolithography for 3D-printing of microfluidic geometries for nucleic acid amplification

PLoS One. 2020 Oct 28;15(10):e0240237. doi: 10.1371/journal.pone.0240237. eCollection 2020.

Authors

Charalampos Tzivelekis¹, Pavlos Sgardelis¹, Kevin Waldron², Richard Whalley¹, Dehong Huo¹, Kenny Dalgarno¹

Affiliations

¹ School of Engineering, Newcastle University, Newcastle, United Kingdom.
² Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle, United Kingdom.

Abstract

Digital Light Processing (DLP) stereolithography (SLA) as a high-resolution 3D printing process offers a low-cost alternative for prototyping of microfluidic geometries, compared to traditional clean-room and workshop-based methods. Here, we investigate DLP-SLA printing performance for the production of micro-chamber chip geometries suitable for Polymerase Chain Reaction (PCR), a key process in molecular diagnostics to amplify nucleic acid sequences. A DLP-SLA fabrication protocol for printed micro-chamber devices with monolithic micro-channels is developed and evaluated. Printed devices were post-processed with ultraviolet (UV) light and solvent baths to reduce PCR inhibiting residuals and further treated with silane coupling agents to passivate the surface, thereby limiting biomolecular adsorption occurences during the reaction. The printed devices were evaluated on a purpose-built infrared (IR) mediated PCR thermocycler. Amplification of 75 base pair long target sequences from genomic DNA templates on fluorosilane and glass modified chips produced amplicons consistent with the control reactions, unlike the non-silanized chips that produced faint or no amplicon. The results indicated good functionality of the IR thermocycler and good PCR compatibility of the printed and silanized SLA polymer. Based on the proposed methods, various microfluidic designs and ideas can be validated in-house at negligible costs without the requirement of tool manufacturing and workshop or clean-room access. Additionally, the versatile chemistry of 3D printing resins enables customised surface properties adding significant value to the printed prototypes. Considering the low setup and unit cost, design flexibility and flexible resin chemistries, DLP-SLA is anticipated to play a key role in future prototyping of microfluidics, particularly in the fields of research biology and molecular diagnostics. From a system point-of-view, the proposed method of thermocycling shows promise for portability and modular integration of funcitonalitites for diagnostic or research applications that utilize nucleic acid amplification technology.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Lab-On-A-Chip Devices
Microfluidics / methods*
Nucleic Acid Amplification Techniques / methods
Polymerase Chain Reaction
Printing, Three-Dimensional*
Stereolithography*

Grants and funding

This research was co-funded by the Engineering and Physical Sciences Research Council (EPSRC, https://epsrc.ukri.org/) (through award EP/L01534X/1), QuantuMDx Ltd (https://quantumdx.com/), and Newcastle University (https://www.ncl.ac.uk/). The EPSRC had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Newcastle University was involved in the study design, data collection, and analysis, the decision to publish and the preparation of the manuscript. QuantumDx was involved in the study design but did not contribute to the data collection, analysis, the decision to publish or the preparation of the manuscript.