Nanoplasmonic pillars engineered for single exosome detection

• Published in: PloS one Vol. 13; no. 8; p. e0202773
• Main Authors: Raghu, Deepa, Christodoulides, Joseph A, Christophersen, Marc, Liu, Jinny L, Anderson, George P, Robitaille, Michael, Byers, Jeff M, Raphael, Marc P
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24-08-2018; Public Library of Science (PLoS)
• Subjects: Adenocarcinoma; Analysis; Analytical chemistry; Armed forces; Biology and Life Sciences; Biomolecules; Biosensors; Cancer; Cell signaling; Engineering and Technology; Exosomes; Exosomes - metabolism; Gold - chemistry; Humans; Laboratories; Low concentrations; Materials science; MCF-7 Cells; Microscopy, Atomic Force; Multiplexing; Nanostructures - chemistry; Nucleic acids; Physical Sciences; Proteins; Real time; Recording; Research and Analysis Methods; RNA; Sensor arrays; Sensors; Stochasticity; Substrates; Surface Plasmon Resonance - methods; Wound healing; Washington DC; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0202773

Exosomes are secreted nanovesicles which incorporate proteins and nucleic acids, thereby enabling multifunctional pathways for intercellular communication. There is an increasing appreciation of the critical role they play in fundamental processes such as development, wound healing and disease progression, yet because of their heterogeneous molecular content and low concentrations in vivo, their detection and characterization remains a challenge. In this work we combine nano- and microfabrication techniques for the creation of nanosensing arrays tailored toward single exosome detection. Elliptically-shaped nanoplasmonic sensors are fabricated to accommodate at most one exosome and individually imaged in real time, enabling the label-free recording of digital responses in a highly multiplexed geometry. This approach results in a three orders of magnitude sensitivity improvement over previously reported real-time, multiplexed platforms. Each nanosensor is elevated atop a quartz nanopillar, minimizing unwanted nonspecific substrate binding contributions. The approach is validated with the detection of exosomes secreted by MCF7 breast adenocarcinoma cells. We demonstrate the increasingly digital and stochastic nature of the response as the number of subsampled nanosensors is reduced from four hundred to one.