No abstract

Immuno-specific enrichment of extracellular vesicles (EVs) can provide important information into cellular pathways underpinning various pathologies and for non-invasive diagnostics, including mass spectrometry-based analyses. Herein, we report an optimised protocol...

A 3D microdevice equipped with a portable pump and a single heater was fabricated integrating RNA amplification and detection functionalities.

We demonstrate the integration of DNA amplification and detection functionalities developed on a lab-on-a-chip microdevice utilizing solid-phase polymerase chain reaction (SP-PCR) for point-of-need (PON) DNA analyses. First, the polycarbonate microdevice was fabricated by thermal bonding  to contain microchambers as reservoirs for performing SP-PCR. Next, the microchambers were subsequently modified with polyethyleneimine and glutaraldehyde for immobilizing amine-modified forward primers. During SP-PCR, the immobilized forward primers and freely diffusing fluorescence-labeled reverse primers cooperated to generate target amplicons, which remained covalently attached to the microchambers for the fluorescence detection. The SP-PCR microdevice was used for the direct identifications of two widely detected foodborne pathogens, namely Salmonella spp. and Staphylococcus aureus, and an alga causing harmful algal blooms annually in South Korea, Cochlodinium polykrikoides. The SP-PCR microdevice would be versatilely applied in PON testing as a universal platform for the fast identification of foodborne pathogens and environmentally threatening biogenic targets.

Immuno-specific enrichment of extracellular vesicles (EVs) originating from specific cells/tissues is a promising source of information towards improving insights into cellular pathways underpinning various pathologies and developing novel non-invasive diagnostic methods. Enrichment is an important aspect in mass spectrometry-based analyses of EVs. Herein, we report a protocol for immuno-magnetic enrichment of subtype specific EVs and their subsequent processing for mass spectrometry. Specifically, we conjugated placental alkaline phosphatase (PLAP) antibodies to magnetic iron oxide nanowires (NWs) derived from bacterial biofilms and demonstrated the utility of this approach by enriching placental specific EVs (containing PLAP) from cell culture media. We demonstrate efficient PLAP+ve EV enrichment for both NW-PLAP and Dynabeads™-PLAP, with PLAP protein recovery (83.7±8.9% and 83.2±5.9%, respectively), high particle-to-protein ratio (7.5±0.7×109 and 7.1 ± 1.2×109, respectively), and low non-specific binding of non-target EVs (7±3.2% and 5.4±2.2%, respectively). Furthermore, our optimized EV enrichment and processing approach identified 2518 and 2545 protein groups with mass spectrometry for NW-PLAP and Dynabead™-PLAP, respectively, with excellent reproducibility (Pearson correlation 0.986 and 0.988). The proposed immuno-specific EVs enrichment and liquid chromatography-tandem mass spectrometry method using naturally occurring iron oxide magnetic NWs or gold-standard Dynabeads™ enables high-quality EV proteomic studies.