Photonic crystals on copolymer film for bacteria detection.

The development of two-dimensional photonic crystals (PCs) on a copolymer film is described in connection with Fresnel reflection spectroscopy and fluorescence microscopy. Label-free detection of Legionella pneumophila was performed using a PC platform with a detection limit of 200 cells/mL. L. pneumophila is well known as the cause of Legionnaires' disease and a lesser form called Pontiac fever. Since death by L. pneumophila infection depends on the early anti-microbial treatment, rapid diagnosis of this disease is critical for efficient treatment and patient survival. Conventional assays have turn-around times measurable in several hours to days, and are limited in their detection of various serogroups. Due to the recent introduction of regulatory guidelines for routine testing of water cooling towers and treatment facilities, biosensors for the on-field detection of Legionella spp. are highly in demand. The versatile and economical immunochips described here can be easily adapted for the monitoring of L. pneumophila serogroups in clinical and environmental samples in a few minutes.

Disposable immunochips for the detection of Legionella pneumophila using electrochemical impedance spectroscopy.

The rapid diagnosis of Legionellosis is crucial for the effective treatment of this disease. Currently, most clinical laboratories utilize rapid immunoassays that are sufficient for the detection of Legionella serogroup 1, but not other clinically relevant serogroups. In this report, the development of a disposable immunochip system is described in connection with electrochemical impedance spectroscopy and fluorescence microscopy. The immunochips were prepared by covalently immobilizing fluorophore-conjugated L. pneumophilaantibodies on Au chips. The analytical performance of the immunochips was optimized as a prescreening tool for L. pneumophila. The versatile immunochips described here can be easily adapted for the monitoring of all Legionella serogroups in clinical and environmental samples.