Biomode’s cutting-edge technology is based on Peptide Nucleic Acid FISH (PNA-FISH) for rapid and accurate pathogen detection
Unlike other molecular methods, PNA-FISH does not involve DNA extraction or amplification, is not susceptible to inhibitory compounds and only detects viable bacterial cells. This is achieved while keeping a competitive price range equivalent to traditional methods.
PNA (Peptide Nucleic Acid) is a synthetic DNA mimic molecule, which instead of the natural deoxyribose sugar backbone presents a backbone composed of repeating N-(2-aminoethyl)-glycine units linked by peptide bonds. Because of its chemical configuration, the nucleobases are positioned in the same place and within the same distance as it occurs to the natural DNA and for that reason it can also hybridize with DNA or RNA.
The neutral feature of PNA molecules confers several advantages when comparing to their DNA counterpart, such as:
- Higher thermal stability between PNA/DNA or PNA/RNA bonding;
- Higher affinity implies that PNA probes usually have smaller sequences (13-18 nucleotides);
- PNA molecules present more resistance to nucleases and proteases.
PNA molecules can easily enter the cell and due to its uncharged nature they do not encounter electrostatic repulsion, which allows a rapid and robust hybridization to nucleic acid targets.
PNA probes can be attached to a fluorochrome so they can be detected by epifluorescence microscopy or flow cytometry using Fluorescence in situ hybridization (FISH).
FISH using PNA probes
The FISH protocol using PNA probes comprises 4 short and easy-to-do steps:
- Fixation (permeabilization of the cell walls);
- Hybridization (probe accesses and hybridizes with the target sequence);
- Washing (ensures that all loosely bound or unbound labeled probes are removed from the sample, hence providing specificity to the detection);
- Visualization of the pathogen using an Epifluorescent Microscope.
Biomode has developed several rapid kits for pathogen detection in food and clinical samples. Each kit is ready-to-use, divided in 5 solutions, making more simple the application of the PNA-FISH protocol.
The whole procedure takes only 3 hours to be fully concluded.
The detection kits compromises the following components:
Fixation solution 2
The procedure is quite easy and fast to perform (hands-on-time < 1 min). It involves the application of the different solutions in 5 simple steps using “eye-drop” bottles. Positive results can be visualized using a fluorescence microscope after a 3h procedure.