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Laser induced degradation of bacterial spores during micro-Raman spectroscopy
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
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2022 (Engelska)Ingår i: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 265, artikel-id 120381Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Micro-Raman spectroscopy combined with optical tweezers is a powerful method to analyze how the biochemical composition and molecular structures of individual biological objects change with time. In this work we investigate laser induced effects in the trapped object. Bacillus thuringiensis spores, which are robust organisms known for their resilience to light, heat, and chemicals are used for this study. We trap spores and monitor the Raman peak from CaDPA (calcium dipicolinic acid), which is a chemical protecting the spore core. We see a correlation between the amount of laser power used in the trap and the release of CaDPA from the spore. At a laser power of 5 mW, the CaDPA from spores in water suspension remain intact over the 90 min experiment, however, at higher laser powers an induced effect could be observed. SEM images of laser exposed spores (after loss of CaDPA Raman peak was confirmed) show a notable alteration of the spores' structure. Our Raman data indicates that the median dose exposure to lose the CaDPA peak was ∼60 J at 808 nm. For decontaminated/deactivated spores, i.e., treated in sodium hypochlorite or peracetic acid solutions, the sensitivity on laser power is even more pronounced and different behavior could be observed on spores treated by the two chemicals. Importantly, the observed effect is most likely photochemical since the increase of the spore temperature is in the order of 0.1 K as suggested by our numerical multiphysics model. Our results show that care must be taken when using micro-Raman spectroscopy on biological objects since photoinduced effects may substantially affect the results.

Ort, förlag, år, upplaga, sidor
Elsevier, 2022. Vol. 265, artikel-id 120381
Nyckelord [en]
Bacteria, Decontamination, Multiphysics modelling, Optical tweezers, Raman spectroscopy, Spores
Nationell ämneskategori
Biofysik Atom- och molekylfysik och optik Cellbiologi
Identifikatorer
URN: urn:nbn:se:umu:diva-187284DOI: 10.1016/j.saa.2021.120381ISI: 000709268600014PubMedID: 34562861Scopus ID: 2-s2.0-85115389622OAI: oai:DiVA.org:umu-187284DiVA, id: diva2:1591732
Forskningsfinansiär
Vetenskapsrådet, 2019-04016Kempestiftelserna, JCK-1916.2Försvarsmakten, 470-A400821Tillgänglig från: 2021-09-07 Skapad: 2021-09-07 Senast uppdaterad: 2025-02-20Bibliografiskt granskad
Ingår i avhandling
1. KNOW YOUR ENEMY: Characterizing Pathogenic Biomaterials Using Laser Tweezers
Öppna denna publikation i ny flik eller fönster >>KNOW YOUR ENEMY: Characterizing Pathogenic Biomaterials Using Laser Tweezers
2022 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Diseases caused by pathogenic agents such as bacteria and viruses result in devastating costs on personal and societal levels. However, it is not just the emergence of new diseases that is problematic. Antibiotic resistance among bacteria makes uncomplicated infections difficult and lethal. Resilient disease-causing spores spread in hospitals, the food industry, and water supplies requiring effective detection and disinfection methods. Further, we face complex neurological diseases where no effective treatment or diagnostic methods exist. Thus, we must increase our fundamental understanding of these diseases to develop effective diagnostic, detection, disinfection, and treatment methods.

Classically, the methods used for detecting and studying the underlying mechanics of pathogenic agents work on a large scale, measuring the average macroscopic behavior and properties of these pathogens. However, just as with humans, the average behavior is not always representative of individual behavior. Therefore, it is also essential to investigate the characteristics of these pathogens on a single cell or particle level. 

This thesis develops and applies optical techniques to characterize pathogenic biomaterial on a single cell or particle level. At the heart of all these studies is our Optical Tweezers (OT) instrument. OT are a tool that allows us to reach into the microscopic world and interact with it. Finally, by combining OT with other experimental techniques, we can chemically characterize biomaterials and develop assays that mimic different biological settings. Using these tools, we investigate bacterial adhesion, disinfection, and detection of pathogenic spores and proteins.

Hopefully, the insights of these studies can lessen the burden on society caused by diseases by helping others develop effective treatment, diagnostic, detection, and disinfection methods in the future. 

Ort, förlag, år, upplaga, sidor
Umeå: Umeå universitet, 2022. s. 73
Nyckelord
Optical Tweezers, Laser Tweezers, Raman Spectroscopy, Bacterial Adhesion, Biophysics, Pili, Bacterial Spores, Endospores, Oocysts, Cryptosporidium, Optics
Nationell ämneskategori
Biofysik Atom- och molekylfysik och optik
Forskningsämne
biologi; fysik
Identifikatorer
urn:nbn:se:umu:diva-192471 (URN)978-91-7855-726-4 (ISBN)978-91-7855-727-1 (ISBN)
Disputation
2022-03-11, NAT.D.410, Naturvetarhuset, Umeå, 09:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2022-02-18 Skapad: 2022-02-14 Senast uppdaterad: 2025-02-20Bibliografiskt granskad

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Malyshev, DmitryÖberg, RasmusDahlberg, TobiasWiklund, KristerAndersson, Magnus

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Malyshev, DmitryÖberg, RasmusDahlberg, TobiasWiklund, KristerAndersson, Magnus
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Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy
BiofysikAtom- och molekylfysik och optikCellbiologi

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