Laser-fabricated gold nanoparticles for lateral flow immunoassays

• Published in: Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2017-01, Vol.149, p.351-357
• Main Authors: Cederquist, Kristin B., Liu, Bing, Grima, Megan R., Dalack, Peter J., Mahorn, Jordan T.
• Format: Article
• Language: English
• Subjects: Antibodies; Antibodies, Monoclonal - chemistry; Antibody density; Assaying; Chorionic Gonadotropin - analysis; Gold; Gold - chemistry; Gold - radiation effects; Gold nanoparticles; Humans; Immunoassay; Laser ablation; Lasers; Lateral flow immunoassays; Metal Nanoparticles; Nanoparticles; Pulsed lasers; Reduction (chemical); Rheology; Sensitivity and Specificity; Surface Properties
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2016.10.035

[Display omitted] •Gold nanoparticles made by laser ablation are easily modified with antibodies.•Monoclonal and polyclonal antibodies adsorb with similar densities.•Antibody density on PLA-gold nanoparticles was 2× of that on gold nanoparticles made by chemical reduction.•More antibodies lead to increased sensitivity in a sandwich lateral flow immunoassay. Gold nanoparticles fabricated by pulsed laser ablation are an attractive alternative over those made by chemical reduction, as they offer a more reactive, chemically-bare surface. In this manuscript, we investigate the interactions of these nanoparticles with different classes of antibodies and quantify surface coverage via a fluorescence-based displacement assay. Saturation surface coverage of monoclonal antibodies was found to be almost 2× higher for particles made by pulsed laser ablation (∼28 antibodies/particle) as opposed to those made by chemical means (∼17 antibodies/particle). This higher coverage translated into ∼2× better immunoassay sensitivity, demonstrated by a sandwich lateral flow assay for human chorionic gonadotropin. This work highlights the advantages of these pulsed laser-fabricated materials and showcases their unique properties for colorimetric assay development.