Tailored Functionalization of Plasmonic Ag/C:H:N:O Nanocomposite for Sensitive and Selective Detection of the Lyme Disease Pathogen

Abstract

Borrelia afzelii, a pathogenic bacterium, causes Lyme disease (LD) in humans which can be debilitating if not diagnosed early. Current diagnostic methods are not sensitive enough for the detection of the pathogen or the serological markers during the very early stages of infection. We report on the ability of functionalized Ag/C:H:N:O nanocomposite to act as an active transducer for Localized Surface Plasmon Resonance (LSPR) detection of the LD pathogen with high selectivity and sensitivity. The LSPR effect is caused by the Ag nanoparticles anchored into the plasma polymer C:H:N:O matrix. The functionalization of Ag/C:H:N:O was done as a sequence of (i) thin-film plasma polymer deposition for the introduction of -NH2 groups that (ii) enable subsequent immobilization of specific antibodies for (iii)  binding of the target agents. Borrelia proteins-specific polyclonal antibodies, Borrelia lysate, and live Borrelia were employed as testing target agents. Detailed investigation indicates both a high selectivity for the target agents and high sensitivity with a practical detection limit in the range of 50 Borrelia on 0.785 cm2 sensor effective area, causing an LSPR red-shift Dl > (4.20 ± 0.71) nm. This proposed diagnostic system would allow for the rapid and early detection of the pathogen causing Lyme disease and faster-personalized treatment of the patients.

Keywords: pathogen detection, localized surface plasmon resonance (LSPR), nanocomposite, Lyme disease, Borrelia, silver nanoparticles, plasma polymerized nylon, plasma-assisted deposition