1. Technology behind novel diagnostic methods for fungal infections.
Technology behind novel diagnostic methods for fungal infections. (A) Fluorescence in situ hybridization. Fluorescent probes against a specific target sequence are mixed with the tested sample and allowed to bind to their complementary DNA sequence, if present in the sample. The excess probes are then washed off, while the bound probes are detected via their fluorescence under a fluorescence microscope. (B) Matrix-assisted laser desorption ionization–time of flight mass spectrometry. The tested sample is added to a well that contains matrix material which has the ability to absorb UV light and transform it into heat. A laser beam is targeted to the mix. The laser beam is absorbed by the matrix, and part of the analyte-matrix mix is vaporized and ionized, creating a cloud of ionized proteins and matrix. This cloud subsequently is subjected to an electric field, which leads the particles to accelerate toward a detector. The mass and charge of each particle determine the time needed to reach the detector. This allows the mass spectrometer to determine the characteristics of the particles within the tested sample. Comparison of the produced spectral pattern against a standard database allows for identification of the microorganism in the sample. (C) Surface enhanced resonance Raman spectroscopy. The tested sample is placed on a rough surface, which helps to create scattered light. DNA probes coupled with specialized dyes that emit light are added to the sample. The probes then bind to the target DNA in the sample, and subsequently, a double-stranded DNA exonuclease is added to the mix and digests all bound probes, while the unbound probes, which are single stranded, are left indigested. Finally, the scattered light from the undigested probe is detected by a sensor and analyzed, thus identifying the DNA sequence of the digested probes. (D) T2 nuclear magnetic resonance. First, the target sequence of a microorganism that is found in the sample is amplified. Subsequently, DNA probes coupled with paramagnetic nanoparticles are added to the amplicon and are allowed to hybridize with the amplified sequence. This changes the T2 relaxation time of the nanoparticles, and the change is detected via magnetic resonance imaging, thus identifying the target.
Marios Arvanitis et al. Clin. Microbiol. Rev. 2014; doi: /CMR