Nanoplasmonic sensors for detecting circulating cancer biomarkers – miRNA, ctDNA, exosomes and CTCs

The detection of cancer biomarkers represents an important aspect of cancer diagnosis and prognosis. Recently, the concept of liquid biopsy has been introduced whereby diagnosis and prognosis are performed by means of analyzing biological fluids obtained from patients to detect and quantify circulating cancer biomarkers. Unlike conventional biopsy whereby primary tumor cells are analyzed, liquid biopsy enables the detection of a wide variety of circulating cancer biomarkers, including microRNA (miRNA), circulating tumor DNA (ctDNA), proteins, exosomes and circulating tumor cells (CTCs). Among the various techniques that have been developed to detect circulating cancer biomarkers, nanoplasmonic sensors represent a promising measurement approach due to high sensitivity and specificity as well as ease of instrumentation and operation. Researchers from Nanyang Technological University discuss the relevance and applicability of three different categories of nanoplasmonic sensing techniques, namely surface plasmon resonance (SPR), localized surface plasmon resonance (LSPR) and surface-enhanced Raman scattering (SERS), for the detection of different classes of circulating cancer biomarkers.


(a) A simplified schematic of a localized surface plasmon resonance (LSPR) sensor setup in transmission mode. The background illustration shows a non-propagating collective oscillation of free electrons in the conduction band of the metallic LSPR transducer upon interaction with light. (b) An example of a LSPR microarray chip. The nanorod microarray fabrication was performed using a one-step microfluidic patterning technique assisted by electrostatic attractive interactions between the nanorods and the substrate surface within microfluidic channels. Subsequently, these nanorode microarrays were integrated in a microfluidic chip with eight parallel microfluidic detection channels consisting of inlet and outlet ports for reagent loading and washing. Specific antibodies were conjugated to the patterned AuNR microarrays using thiolated cross-linker and EDC/NHC chemistry.

Ferhan AR, Jackman JA, Park JH, Cho NJ, Kim DH. (2017) Nanoplasmonic sensors for detecting circulating cancer biomarkers. Adv Drug Deliv Rev [Epub ahead of print]. [abstract]

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