NIOM involved in study for alternative antibacterial methods

– We investigated the release of LC from the collagen gels and the phototoxic effect of UVA-irradiated LC against planktonic Staphylococcus (S.) aureus, says Bruzell.

 

 

 

 

 

 

 

 

 

 

 

 

 

– The study is a proof of concept of the release and phototoxic effects of an endogenous photocrosslinker embedded in a biopolymer.

The World Health Organization (WHO) has called for the development of alternative antibacterial methods. In response to this, a team involving three NIOM scientists have investigated endogenous compounds and biopolymers.

– It was an interesting study, where we did show proof of concept, says Ellen Bruzell.

Bruzell, a senior scientist at NIOM, joined the study, which was initiated by Hanne Hjorth Tønnesen and Krister Gjestvang Grønlien from the Department of Pharmacy, University of Oslo. They were also joined by NIOM colleagues Håkon Valen and Maria Pain. The resulting paper, Bacterial phototoxicity of lumichrome photocrosslinked collagen hydrogels, was published in December 2022.

– Lumichrome, or LC, is an endogenous, lipophilic degradation product of riboflavin, meaning vitamin B2. It can act as a photosensitizer for antimicrobial applications, explains Bruzell.

Investigated release

LC is also a photocrosslinker of collagen. Crosslinked collagen hydrogels were prepared with two types of cyclodextrins (CDs), namely (2-hydroxypropyl)-β-CD (HPβCD) and -γ-CD (HPγCD), to improve the aqueous solubility of LC.

– We investigated the release of LC from the collagen gels and the phototoxic effect of UVA-irradiated LC against planktonic Staphylococcus (S.) aureus, says Bruzell.

They noticed irradiation of LC hydrogels complexed with either CD resulted in similar levels of bacterial death despite the HPγCD gels containing half the LC concentration of the HPβCD gels.

– This effect may be explained by the higher complexation efficiency and stability of the LC-HPβCD complex, slowing down the LC release, Bruzell says.

Proof of concept

Irradiation of released LC had a modest antibacterial effect.

– The study is a proof of concept of the release and phototoxic effects of an endogenous photocrosslinker embedded in a biopolymer. With further development, this method could become a sustainable antibacterial alternative to conventional therapy of, e.g., infected wounds, Bruzell says.

 

Illustration by Krister Grønlien showing schematic of the bacterial phototoxicity experiment. Published in Sustainable Chemistry and Pharmacy.

Reference:

Bacterial phototoxicity of lumichrome photocrosslinked collagen hydrogels
Grønlien KG, Valen H, Pain M, Bruzell E, Tønnesen HH.
Sustainable Chemistry and Pharmacy, Volume 31
https://doi.org/10.1016/j.scp.2022.100958

NIOM Newsletter March 2023

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