Fluorescence Lifetime Imaging Microscopy of Porphyrins in Helicobacter pylori Biofilms.
Antonella BattistiPaola MoriciAntonella SgarbossaPublished in: Pharmaceutics (2021)
Bacterial biofilm constitutes a strong barrier against the penetration of drugs and against the action of the host immune system causing persistent infections hardly treatable by antibiotic therapy. Helicobacter pylori (Hp), the main causative agent for gastritis, peptic ulcer and gastric adenocarcinoma, can form a biofilm composed by an exopolysaccharide matrix layer covering the gastric surface where the bacterial cells become resistant and tolerant to the commonly used antibiotics clarithromycin, amoxicillin and metronidazole. Antimicrobial PhotoDynamic Therapy (aPDT) was proposed as an alternative treatment strategy for eradicating bacterial infections, particularly effective for Hp since this microorganism produces and stores up photosensitizing porphyrins. The knowledge of the photophysical characteristics of Hp porphyrins in their physiological biofilm microenvironment is crucial to implement and optimize the photodynamic treatment. Fluorescence lifetime imaging microscopy (FLIM) of intrinsic bacterial porphyrins was performed and data were analyzed by the 'fit-free' phasor approach in order to map the distribution of the different fluorescent species within Hp biofilm. Porphyrins inside bacteria were easily distinguished from those dispersed in the matrix suggesting FLIM-phasor technique as a sensitive and rapid tool to monitor the photosensitizer distribution inside bacterial biofilms and to better orientate the phototherapeutic strategy.
Keyphrases
- helicobacter pylori
- candida albicans
- staphylococcus aureus
- photodynamic therapy
- helicobacter pylori infection
- pseudomonas aeruginosa
- high resolution
- single molecule
- biofilm formation
- stem cells
- squamous cell carcinoma
- fluorescence imaging
- healthcare
- induced apoptosis
- label free
- electronic health record
- high throughput
- optical coherence tomography
- mass spectrometry
- escherichia coli
- signaling pathway
- cystic fibrosis
- drug delivery
- cell cycle arrest
- deep learning
- big data
- cell death
- living cells
- replacement therapy
- high density
- rectal cancer