Hybridization-based DNA biosensing with a limit of detection of 4 fM in 30 s using an electrohydrodynamic concentration module fabricated by grayscale lithography

• Published in: Biomicrofluidics Vol. 16; no. 4; p. 044111
• Main Authors: Tijunelyte, Inga, Teillet, Jeffrey, Bruand, Paul, Courson, Rémi, Lecestre, Aurélie, Joseph, Pierre, Bancaud, Aurélien
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.07.2022; AIP Publishing LLC
• Subjects: Electrohydrodynamics; Engineering Sciences; Fluorimetry; Gray scale; Materials; Micro and nanotechnologies; Microelectronics; Microfluidics; Modules; Nucleic acids; Nucleotides; Photolithography; Regular; Sensitivity enhancement
• ISSN: 1932-1058; 1932-1058
• DOI: 10.1063/5.0073542

Speeding up and enhancing the performances of nucleic acid biosensing technologies have remained drivers for innovation. Here, we optimize a fluorimetry-based technology for DNA detection based on the concentration of linear targets paired with probes. The concentration module consists of a microfluidic channel with the shape of a funnel in which we monitor a viscoelastic flow and a counter-electrophoretic force. We report that the technology performs better with a target longer than 100 nucleotides (nt) and a probe shorter than 30 nt. We also prove that the control of the funnel geometry in 2.5D using grayscale lithography enhances sensitivity by 100-fold in comparison to chips obtained by conventional photolithography. With these optimized settings, we demonstrate a limit of detection of 4 fM in 30 s and a detection range of more than five decades. This technology hence provides an excellent balance between sensitivity and time to result.