Mixed stimuli-responsive magnetic and gold nanoparticle system for rapid purification, enrichment, and detection of biomarkers.
A new diagnostic system for the enrichment and detection of protein biomarkers from human plasma is presented. Gold nanoparticles (AuNPs) were surface-modified with a diblock copolymer synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. The diblock copolymer contained a thermally responsive poly(N-isopropylacrylamide) (pNIPAAm) block, a cationic amine-containing block, and a semi-telechelic PEG₂-biotin end group. When a mixed suspension of 23 nm pNIPAAm-modified AuNPs was heated with pNIPAAm-coated 10 nm iron oxide magnetic nanoparticles (mNPs) in human plasma, the thermally responsive pNIPAAm directed the formation of mixed AuNP/mNP aggregates that could be separated efficiently with a magnet. Model studies showed that this mixed nanoparticle system could efficiently purify and strongly enrich the model biomarker protein streptavidin in spiked human plasma. A 10 ng/mL streptavidin sample was mixed with the biotinylated pNIPAAm-modified AuNPs and magnetically separated in the mixed nanoparticle system with pNIPAAm mNPs. The aggregates were concentrated into a 50-fold smaller fluid volume at room temperature where the gold nanoparticle reagent redissolved with the streptavidin target still bound. The concentrated gold-labeled streptavidin could be subsequently analyzed directly using lateral flow immunochromatography. This rapid capture and enrichment module thus utilizes the mixed stimuli-responsive nanoparticle system to achieve concentration of a gold-labeled biomarker that can be directly analyzed using lateral flow or other rapid diagnostic strategies.
Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA.
Michael A
MA
Nash
Paul
P
Yager
Allan S
AS
Hoffman
Patrick S
PS
Stayton
D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D015415:Biomarkers / Q000097:blood* / Q000737:chemistry; D001710:Biotin / Q000737:chemistry / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D002846:Chromatography, Affinity; D005290:Ferric Compounds / Q000737:chemistry / Q000378:metabolism; D017022:Flow Injection Analysis; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008280:Magnetics / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D019809:Streptavidin / Q000097:blood* / Q000737:chemistry; D013696:Temperature
D000178:Acrylamides; D000180:Acrylic Resins; D015415:Biomarkers; D002412:Cations; D005290:Ferric Compounds; D011108:Polymers; C000499:ferric oxide; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols; D001710:Biotin; D006046:Gold; D019809:Streptavidin