UNAIR FST lecturer explores potential of photodynamic inactivation as solution to reduce bacterial biofilms

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Illustration by Feri Fenoria

UNAIR NEWS – In history, it has been proven since the early 1990s that bacteria causing disease in humans are capable of forming biofilms. In a research on “Photodynamic Inactivation, Solution to Reducing Bacterial Biofilms”, Dr. Suryani Dyah Astuti, M.Si., first explained that, bacteria capable of producing biofilms are associated with chronic infectious diseases. One of them is Staphylococcus aureus (S.aureus).

She explained that S. aureus is a normal flora that lives commensally on human skin, nasal passages, or throat. In abnormal conditions, these bacteria can cause some diseases.

“From mild skin diseases such as skin infections, acne vulgaris, cellulitisfolliculitis to severe diseases such as pneumonia, meningitis, osteomyelitis endocarditis, toxic shock syndrome, and septicemia,” she said.

Furthermore, Dr. Dyah, also explained about biofilm which is a bacterial cell community that is structured and attached to one another. She explained that these bacteria are able to produce polymer matrices and are able to attach to biological surfaces and inanimate objects.

“With this formation, biofilm-making bacteria are able to withstand extreme environments endangering these bacteria. Bacteria in biofilms are able to withstand antibiotics, disinfectants, and even able to withstand the host immune system,” she explained.

In her research, Dr. Dyah explained that clinical manifestations of infection by biofilm-making bacteria in the presence of antibiotic resistance. Generally, antibiotic therapy will only kill planktonic bacterial cells (swimming outside the biofilm, ed) while the form of bacteria that is tightly arranged in the biofilm will stay alive and develop and will release the form of planktonic cells out of the biofilm formation. So, she explained, alternative methods that were effective and selective in killing bacteria were needed.

“One of them is using the photodynamic method that utilizes light and photosensitizers,” she explained.

Moreover, Dr. Dyah also said that the results of the research showed that the irradiation of light with a wavelength spectrum corresponding to the porphyrin absorption spectrum of photosensitizers with the right dose of radiation energy can cause photoinactivation of bacterial cells.

“It is known that, the mechanism of photoinactivation involves the process of photosensitization, the process of light absorption by bacterial porphyrins which in turn activates the occurrence of further chemical reactions producing various reactive oxygen species. Photosensitization depends on the type and quantity of photosensitizer and the suitability of the light spectrum with the photosensitizer absorption spectrum “, she said.

In that research, the laser was chosen as one of the sources of light because it matches the absorbent spectrum of photosensitizer porphyrins. Furthermore, the type of laser used is diode laser because it has advantages in terms of physical size that is small, lightweight, portable, not easily broken and simple in assembly at a relatively cheap price.

In the end, Dr. Dyah revealed the results showed the success of photodynamic inactivation using diode lasers to reduce biofilms without causing bacterial resistance. So the photodynamic method as a method of bacterial inactivation is very promising in the future.

Author: Asthesia Dhea Cantika

Editor : Khefti Al Mawalia

Link of the article:


Astuti S.D., Drantantiyas N.D.G., Putra A.P., Puspita P.S., Syahrom A., Suhariningsih S. Photodynamic effectiveness of laser diode combined with ozone to reduce Staphylococcus aureus biofilm with exogenous chlorophyll of Dracaena angustifolia leaves // Biomedical photonics. Vol. 8, No. 2. – P. 4–13.

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