In laboratory tests, the technique completely eliminated the bacterium. However, a challenge arose: inside the lungs there is a natural layer called pulmonary surfactant, which protects the alveoli during breathing. This layer ended up trapping the dye and reducing the treatment’s effectiveness.
To overcome this obstacle, the scientists combined the dye with Gantrez, a polymer safe for medical use that acts as a carrier, helping the dye cross the lungs’ natural barrier and reach the bacteria. With this combination, the number of microorganisms was reduced thousands of times, even in the presence of the pulmonary barrier – showing the technique’s potential to work under conditions closer to those in the human body.
“Each step toward making the method clinically applicable brings new challenges. The most recent was overcoming the lungs’ natural barrier: the surfactant,” highlights Fernanda Alves. “With the addition of Gantrez to the treatment, we achieved very encouraging results, giving us hope for the next stages, first in animal models and then in clinical studies.”
Although the tests are still in the laboratory phase, the results show promise. If confirmed in studies with animals and later with patients, the therapy could become an alternative to antibiotics in cases of severe and resistant pneumonia. According to the study’s authors, this is an important step in combating so-called “superbugs,” which already represent one of the greatest public health threats of the 21st century.
The study is authored by Fernanda Alves, Isabelle Almeida de Lima, Lorraine Gabriele Fiuza, and Natalia Mayumi Imada from IFSC and Texas A&M University; Zoe Arnaut from the University of Coimbra; and Vanderlei Salvador Bagnato, professor at IFSC and Texas A&M University.
Published in the scientific journal Pathogens, the article Optimizing Photosensitizer Delivery for Effective Photodynamic Inactivation of Klebsiella pneumoniae Under Lung Surfactant Conditions can be accessed at this link.
*Rui Sintra, IFSC Communication Office. Adapted by Júlio Bernardes
**Intern supervised by Moisés Dorado
English version: Nexus Traduções, edited by Denis Pacheco
