Bioresponsive hydrogel microlenses.
We report investigations of bioresponsive hydrogel microlenses as a new protein detection technology. Stimuli-responsive poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc) microgels have been synthesized via free-radical precipitation polymerization. These hydrogel microparticles were then functionalized with biotin via EDC coupling. Hydrogel microlenses were prepared from the particles via Coulombic assembly onto a silane-modified glass substrate. Arrays containing both pNIPAm-co-AAc microgels (as an internal control) and biotinylated pNIPAm-co-AAc microgels were then used to detect multivalent binding of both avidin and polyclonal anti-biotin. Protein binding was determined by monitoring the optical properties of the microlenses using a brightfield optical microscopy technique. The microlens method is shown to be very specific for the target protein, with no detectable interference from nonspecific protein binding. Finally, the reversibility of the hydrogel microlens assay has been studied in the case of anti-biotin to determine the potential application of the microlens assay technology in a displacement-type assay. These results suggest that the microlens method may be an appropriate one for label-free detection of proteins or small molecules via displacement of tethered protein--ligand pairs.
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
Jongseong
J
Kim
Satish
S
Nayak
L Andrew
LA
Lyon
D000178:Acrylamides / Q000138:chemical synthesis*; D000179:Acrylates / Q000138:chemical synthesis*; D000906:Antibodies / Q000276:immunology; D001360:Avidin / Q000737:chemistry / Q000378:metabolism; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000494:pharmacology*; D001710:Biotin / Q000737:chemistry / Q000378:metabolism; D019921:Biotinylation; D005609:Free Radicals / Q000737:chemistry; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000138:chemical synthesis / Q000494:pharmacology*; D007909:Lenses; D008024:Ligands; D008853:Microscopy; D008904:Miniaturization; D055095:Optics and Photonics; D011108:Polymers / Q000138:chemical synthesis*; D011485:Protein Binding
D000178:Acrylamides; D000179:Acrylates; D000906:Antibodies; D001672:Biocompatible Materials; D005609:Free Radicals; D008024:Ligands; C090629:N-isopropylacrylamide-acrylic acid copolymer; D011108:Polymers; D001360:Avidin; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D001710:Biotin