Magneto-Fluorescent Microbeads for Bacteria Detection Constructed from Superparamagnetic FeO Nanoparticles and AIS/ZnS Quantum Dots.

The efficient and sensitive detection of pathogenic microorganisms in aqueous environments, such as water used in medical applications, drinking water, and cooling water of industrial plants, requires simple and fast methods suitable for multiplexed detection such as flow cytometry (FCM) with optically encoded carrier beads. For this purpose, we combine fluorescent Cd-free Ag-In-S ternary quantum dots (t-QDs) with fluorescence lifetimes (LTs) of several hundred nanoseconds and superparamagnetic FeO nanoparticles (SPIONs) with mesoporous CaCO microbeads to a magneto-fluorescent bead platform that can be surface-functionalized with bioligands, such as antibodies. This inorganic bead platform enables immuno-magnetic separation, target enrichment, and target quantification with optical readout.

Fast label-free detection of Legionella spp. in biofilms by applying immunomagnetic beads and Raman spectroscopy.

Legionellae colonize biofilms, can form a biofilm by itself and multiply intracellularly within the protozoa commonly found in water distribution systems. Approximately half of the known species are pathogenic and have been connected to severe multisystem Legionnaires' disease. The detection methods for Legionella spp.

Raman Spectroscopic Characterization of Packaged L. pneumophila Strains Expelled by T. thermophila.

The intracellular lifestyle of L. pneumophila within protozoa is considered to be a fundamental process that supports its survival in nature. However, after ingesting the cells of L.

Raman spectroscopic differentiation of planktonic bacteria and biofilms.

Both biofilm formations as well as planktonic cells of water bacteria such as diverse species of the Legionella genus as well as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli were examined in detail by Raman microspectroscopy. Production of various molecules involved in biofilm formation of tested species in nutrient-deficient media such as tap water was observed and was particularly evident in the biofilms formed by six Legionella species. Biofilms of selected species of the Legionella genus differ significantly from the planktonic cells of the same organisms in their lipid amount.

Identification of water pathogens by Raman microspectroscopy.

Legionella species can be found living in water mostly in a viable but nonculturable state or associated with protozoa and complex biofilm formations. Isolation and afterwards identification of these pathogens from environmental samples by using common identification procedures based on cultivation are extremely difficult and prolonged. The development of fast and sensitive method based on the cultivation free identification of bacteria is necessary.