Application of a Medical Diode Laser (810 nm) for Disinfecting Small Microbiologically Contaminated Spots on Degraded Collagenous Materials for Improved Biosafety in Objects of Exceptional Historical Value From the Auschwitz-Birkenau State Museum and Protection of Human Health

Abstract

The research aim was to optimize the operating parameters of a diode laser irradiation for the effective disinfection of degraded collagenous materials. Historical leather shoes stored at the Auschwitz-Birkenau State Museum in Oświęcim (Poland) were the main study objects. Surfaces of contaminated small spots occurring on the degraded materials were sampled with moistened swabs and microbiologically examined using the molecular techniques MALDI-TOF MS, 16S rRNA, and NGS sequencing. The surfaces were colonized by bacteria with 106 CFU/100 cm2 and 104 CFU/100 cm2 by fungi, on average. Microorganisms of the genera Bacillus and Penicillium were predominant. The effectiveness of the laser treatment was assessed for the new and degraded collagenous materials against isolated environmental strains using four variants of exposure time and number of repetitions. 0.3 W/CW 2 × 2 min variant was the most effective and also did not noticeably change the color of the treated samples. The variant caused a reduction in the numbers of microorganisms by 96–100%. After 1 month, four types of leather were subjected to comprehensive physico-chemical analyses. SEM and FTIR techniques confirmed that laser irradiation in the selected optimal variant did not affect the surface morphology and collagen structure, while XPS technique enabled detection of subtle changes in non-historical protective coatings on the surfaces of tested degraded historical materials.

Optimization of the Process of Eliminating Microorganisms Harmful to Human Health and Threatening Objects Isolated from Historical Materials from the Auschwitz-Birkenau State Museum in Poland (A-BSM) Collection with the Use of Ethanol in the Form of Mist

“…The A-BSM successfully performs disinfection with a diode laser, for which in the medical area, a reduction of bacteria and fungi from 60% to 100% was achieved on various materials [ 18 , 19 , 20 , 21 , 22 ]; on historical collagen material in the A-BSM, a reduction of 78–92% was achieved, and on cellulose, 90–100% was achieved [ 8 , 23 , 24 ].…”

Analysis of the Microbiome on the Surface of Corroded Titanium Dental Implants in Patients with Periimplantitis and Diode Laser Irradiation as an Aid in the Implant Prosthetic Treatment: An Ex Vivo Study

“…In these studies, a reduction of 87.75–100% was achieved and a smaller reduction in the number of microorganisms of 38–100% was found on the dental composite [ 54 ]. On other cellulose material, Rybitwa et al achieved 92.17–100.00% and on collagen material, 96–100% [ 55 , 56 ].…”

Analysis of the Surface of Historic Fabric from the Auschwitz-Birkenau State Museum after Treatment with Ethanol Mist Used to Eliminate Microorganisms Harmful to Human Health

“…To further assess the potential impact of ethanol mist on the near-surface layer at PMA-B, X-ray photoelectron spectroscopy (XPS) studies were conducted, allowing for the capture of changes up to a depth of 2-3 nm. XPS is successfully utilized for studying both biotic and abiotic surfaces [23].…”