Lipid coated liquid crystal droplets for the on-chip detection of antimicrobial peptides

• Published in: Lab on a chip Vol. 19; no. 6; pp. 182 - 189
• Main Authors: Bao, Peng, Paterson, Daniel A, Harrison, Patrick L, Miller, Keith, Peyman, Sally, Jones, J. Cliff, Sandoe, Jonathan, Evans, Stephen D, Bushby, Richard J, Gleeson, Helen F
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 13.03.2019
• Subjects: Antiinfectives and antibacterials; Antimicrobial Cationic Peptides - analysis; Biological activity; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensors; Coating; Configurations; Diagnostic software; Diagnostic systems; Disruption; Droplets; Lab-On-A-Chip Devices; Lipids; Liquid crystals; Liquid Crystals - chemistry; Microfluidic devices; Microscopy, Fluorescence; Nematic crystals; Peptides; Phospholipids; Phospholipids - chemistry; Polydimethylsiloxane; Silicone resins; Unilamellar Liposomes - chemistry
• ISSN: 1473-0197; 1473-0189; 1473-0189
• DOI: 10.1039/c8lc01291a

We describe a novel biosensor based on phospholipid-coated nematic liquid crystal (LC) droplets and demonstrate the detection of Smp43, a model antimicrobial peptide (AMP) from the venom of North African scorpion Scorpio maurus palmatus . Mono-disperse lipid-coated LC droplets of diameter 16.7 ± 0.2 μm were generated using PDMS microfluidic devices with a flow-focusing configuration and were the target for AMPs. The droplets were trapped in a bespoke microfluidic trap structure and were simultaneously treated with Smp43 at gradient concentrations in six different chambers. The disruption of the lipid monolayer by the Smp43 was detected (<6 μM) at concentrations well within its biologically active range, indicated by a dramatic change in the appearance of the droplets associated with the transition from a typical radial configuration to a bipolar configuration, which is readily observed by polarizing microscopy. This suggests the system has feasibility as a drug-discovery screening tool. Further, compared to previously reported LC droplet biosensors, this LC droplet biosensor with a lipid coating is more biologically relevant and its ease of use in detecting membrane-related biological processes and interactions has the potential for development as a reliable, low-cost and disposable point of care diagnostic tool. Lipid coated liquid crystal droplets have been trapped in a novel trap structure for the on-chip detection of a model antimicrobial peptide - Smp43, an α-helical peptide from Scorpion Venom.