TY  - JOUR
A1  - Bertz, Morten
A1  - Molinnus, Denise
A1  - Schöning, Michael Josef
A1  - Homma, Takayuki
T1  - Real-time monitoring of H₂O₂ sterilization on individual bacillus atrophaeus spores by optical sensing with trapping Raman spectroscopy
JF  - Chemosensors
N2  - Hydrogen peroxide (H₂O₂), a strong oxidizer, is a commonly used sterilization agent employed during aseptic food processing and medical applications. To assess the sterilization efficiency with H₂O₂, bacterial spores are common microbial systems due to their remarkable robustness against a wide variety of decontamination strategies. Despite their widespread use, there is, however, only little information about the detailed time-resolved mechanism underlying the oxidative spore death by H₂O₂. In this work, we investigate chemical and morphological changes of individual Bacillus atrophaeus spores undergoing oxidative damage using optical sensing with trapping Raman microscopy in real-time. The time-resolved experiments reveal that spore death involves two distinct phases: (i) an initial phase dominated by the fast release of dipicolinic acid (DPA), a major spore biomarker, which indicates the rupture of the spore’s core; and (ii) the oxidation of the remaining spore material resulting in the subsequent fragmentation of the spores’ coat. Simultaneous observation of the spore morphology by optical microscopy corroborates these mechanisms. The dependence of the onset of DPA release and the time constant of spore fragmentation on H₂O₂ shows that the formation of reactive oxygen species from H₂O₂ is the rate-limiting factor of oxidative spore death.
KW  - DPA (dipicolinic acid)
KW  - sterilization
KW  - Bacillus atrophaeus spores
KW  - optical trapping
KW  - Raman spectroscopy
KW  - optical sensor setup
Y1  - 2023
U6  - http://dx.doi.org/10.3390/chemosensors11080445
SN  - 2227-9040
N1  - This article belongs to the Special Issue "Biosensors and Chemical Sensors for Food and Healthcare Monitoring—Celebrating the 10th Anniversary"
VL  - 8
IS  - 11
PB  - MDPI
CY  - Basel
ER  -