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Updated: Apr 20, 2026
Detection of Bacteria Using Fluorogenic DNAzymes
Published on: May 28, 2012
A new colorimetric peptide nucleic acid-based assay for the specific detection of bacteria
Carina Almeida1, Diogo Constante, André Ferreira
1LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.
Aim:
Developments on synthetic molecules, such as peptide nucleic acid (PNA), make FISH procedures more robust for microbial identification. Fluorochromes use might hinder a broader implementation of PNA-FISH, but colorimetric applications are inexistent so far.
Methods:
A biotin-labeled eubacteria probe was used to develop a colorimetric PNA-in situ hybridization (ISH) assay. An enzymatic-conjugate, targeting biotin, was introduced. The procedure was optimized and evaluated regarding sensitivity, specificity and detection limit.
Results:
RESULTS have shown strong ISH signals. The method was specific, but permeabilization problems were observed for Gram-positive bacteria. Detection limit was 5 × 10(7) CFU/ml, limiting current applications to pre-enriched samples.
Conclusion:
The PNA-ISH procedure described here is a simple alternative to other detection methods, and is also the base for the development of other PNA colorimetric systems.
