Advanced Photon Source

An Office of Science National User Facility

NST Seminar: Antimicrobial Photodynamic Therapy with Ga-Protoporphyrin Derivatives Against Pathogenic Bacteria

Type Of Event: 
Building Number: 
Room Number: 
Ana Morales-de-Echegaray, Purdue University
Tijana Rajh
Start Date: 
Thursday, March 15, 2018
Start Time: 
2:00 p.m.

Bacterial pathogens have the ability to acquire hemin through different mechanisms. One mechanism is through cell-surface hemin receptors (CSHRs), which are capable of rapid hemin recognition and make the bacteria vulnerable to antimicrobial photodynamic inactivation (aPDI). The work presented here focuses on gallium protoporphyrin IX (GaPpIX) as a photosensitizer for aPDI against staphylococci. GaPpIX is rapidly uptaken into CSHR-expressing bacteria, and is easily detected within minutes of exposure. Assessment of GaPpIX as a photosensitizer against laboratory strains of Staphylococcus aureus, clinical isolates of methicillin-resistant S. aureus (MRSA), and S. epidermis shows aPDI activity at low micromolar levels, following 15 minutes of exposure to a compact fluorescent light bulb or at nanomolar levels when exposed for 10 seconds with a light emitting diode (LED) light source. Activity also had greater potency when compared against metal-free protoporphyrin (PpIX). These results led to the design of a more potent photosensitizer by incorporating GaPpIX into apohemoglobin (GaPpIXHb) and using the hybrid protein to coat 10-nm silver nanoparticles (AgNPs). The GaPpIXHb-AgNP complexes exhibit remarkable aPDI activity using nanomolar loadings of GaPpIX against clinical MRSA isolates.

footer for adding event

To report an event that is not listed, please contact webmaster, for additional synchrotron-related conferences, check