Biosensing using straight long-range surface plasmon waveguides.

Optics express (2013-02-08)
Oleksiy Krupin, Hamoudi Asiri, Chen Wang, R Niall Tait, Pierre Berini
ABSTRACT

Straight long-range surface plasmon waveguides are demonstrated as biosensors for the detection of cells, proteins and changes in the bulk refractive index of solutions. The sensors consist of 5 μm wide 22 nm thick Au stripes embedded in polymer (CYTOP™) with microfluidic channels etched into the top cladding. Bulk sensing is demonstrated by sequentially injecting six solutions of different refractive indices in 2 × 10(-3) RIU increments; such index steps were detected with a signal-to-noise ratio of ~1000. Selective capture of cells is demonstrated using Au waveguides functionalized with antibodies against blood group A, and red blood cells of group A and O in buffer as positive and negative analyte. Bovine serum albumin in buffer was used to demonstrate protein sensing. A monolayer of bovine serum albumin physisorbed on a carboxyl-terminated self-assembled monolayer on Au was detected with a signal-to-noise ratio of ~300. Overall, the biosensor demonstrated a good capability for detecting bulk changes in solution and for sensing analyte over a very wide range of mass (from cells to proteins). The biosensors are compact, inexpensive to fabricate, and may find use over a wide range of cost-sensitive sensing and detection applications.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acetone, ACS reagent, ≥99.5%
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Acetone, HPLC Plus, for HPLC, GC, and residue analysis, ≥99.9%
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Acetone, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.5% (GC)
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Supelco
Acetone, analytical standard
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Acetone, suitable for HPLC, ≥99.9%
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Acetone, puriss., meets analytical specification of Ph. Eur., BP, NF, ≥99% (GC)
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Acetone, Pharmaceutical Secondary Standard; Certified Reference Material
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Acetone, ACS reagent, ≥99.5%
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Acetone, histological grade, ≥99.5%
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Acetone solution, certified reference material, 2000 μg/mL in methanol: water (9:1)
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Acetone, ≥99%, meets FCC analytical specifications
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Acetone solution, contains 20.0 % (v/v) acetonitrile, suitable for HPLC