Optical fiber bundles were purchased from Schott North America (Southbridge, MA). Non-reinforced gloss silicone sheeting was obtained from Specialty Manufacturing (Saginaw, MI). Hydrochloric acid, anhydrous ethanol, and molecular biology grade Tween-20 were all from Sigma-Aldrich (Saint Louis, MO). 2.7-μm-diam. carboxyl-terminated magnetic beads were purchased from Varian, Inc. (Lake Forest, CA). Monoclonal anti-human TNF-α capture antibody, polyclonal anti-human TNF-α detection antibody, and recombinant human TNF-α were purchased from R&D Systems (Minneapolis, MN). Monoclonal anti-PSA capture antibody, monoclonal anti-PSA detection antibody, and purified PSA were purchased from BiosPacific (Emeryville, CA); the detection antibody was biotinylated using standard methods. 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), N-hydroxysulfosuccinimide (NHS), and SuperBlock® T-20 Blocking Buffer were purchased from Thermo Scientific (Rockford, IL). Purified DNA was purchased from Integrated DNA Technologies (Coralville, IA). Streptavidin-β-galactosidase (SβG) was conjugated in house using standard protocols. Resorufin-β-D-galactopyranoside (RGP) was purchased from Invitrogen (Carlsbad, CA). The fiber polisher and polishing consumables were purchased from Allied High Tech Products (Rancho Dominguez, CA).