Opto-chemical disinfection of bacterial pathogens in mature biofilms grown in flexible endoscope

Van Nam Tran, Periaswamy Sivagnanam Saravana, Suhyun Park, Fazlurrahman Khan, Van Gia Truong, Seok Jeong, Don Haeng Lee, Byung Soo Chun, Young Mog Kim, Hyun Wook Kang

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Flexible endoscope reprocessing is an important requirement to minimize the risk of cross-infection between patients due to incomplete disinfection of a bacteria biofilm. The present study introduces a novel opto-chemical treatment to disinfect microbial biofilms (both Gram-positive and Gram-negative bacterial biofilms), commonly found in flexible endoscopes. A low concentration disinfectant combined with infrared and blue light irradiations was applied to disinfect the bacterial biofilms in the endoscope. A basket-integrated optical device was designed to deliver uniform and concentric light onto the channel surface of the endoscope. Colony-forming unit assays were performed to quantify the vial cells while scanning electron microscopy (SEM) illustrated an extracellular matrix (ECM) of the bacterial biofilm. The infrared light irradiation heated the surface of the bacterial biofilm to ~ 65oC. The blue light irradiation induced a relative temperature increase of 30oC on the bacterial biofilm. The results showed that the opto-chemical treatment reduced approximately 7.5-log10 of the bacterial biofilm, which was four times higher than that of a standard disinfectant solution (2% glutaraldehyde). In comparison with the control untreated samples with intact ECMs, the SEM images showed significant damage to the bacterial biofilm under the opto-chemical treatment. The combined treatment induced antimicrobial effects in terms of inhibition of protein synthesis, thermal destruction, and oxidative stress, eradicating the bacterial biofilm more than the standard chemical disinfection. The proposed technique could be an alternative approach to disinfect the microbial biofilms and minimize the risk of secondary infection in endoscopy-related medical facilities.

Original languageEnglish
Title of host publicationSPIE Advanced Biophotonics Conference, SPIE ABC 2021
EditorsEuiheon Chung, Ki-Hun Jeong, Chulmin Joo, Woonggyu Jung, Hyun-Wook Kang, Chang-Seok Kim, Chulhong Kim, Pilhan Kim, Hongki Yoo
ISBN (Electronic)9781510651944
StatePublished - 2021
Event2021 SPIE Advanced Biophotonics Conference, SPIE ABC 2021 - Busan, Korea, Republic of
Duration: 4 Nov 20216 Nov 2021

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


Conference2021 SPIE Advanced Biophotonics Conference, SPIE ABC 2021
Country/TerritoryKorea, Republic of

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1A2C2003733) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2021R1A6A1A03039211).

Publisher Copyright:
© 2022 SPIE.


  • Bacteria biofilm
  • Blue light
  • Disinfection
  • Flexible endoscope
  • Glutaraldehyde
  • Infrared light


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