Raman Microspectroscopy-Based Identification of Individual Fungal Spores as Potential Indicators of Indoor Contamination and Moisture-Related Building Damage

Abstract

We present an application of Raman microspectroscopy (RMS) for the rapid characterization and identification of individual spores from several species of microfungi. The RMS-based methodology requires minimal sample preparation and small sample volumes for analyses. Hence, it is suitable for preserving sample integrity while providing micrometer-scale spatial resolution required for the characterization of individual cells. We present the acquisition of unique Raman spectral signatures from intact fungal spores dispersed on commercially available aluminum foil substrate. The RMS-based method has been used to compile a reference library of Raman spectra from several species of microfungi typically associated with damp indoor environments. The acquired reference spectral library has subsequently been used to identify individual microfungal spores through direct comparison of the spore Raman spectra with the reference spectral signatures in the library. Moreover, the distinct peak structures of Raman spectra provide detailed insight into the overall chemical composition of spores. We anticipate potential application of this methodology in the fields of public health, forensic sciences, and environmental microbiology.

Chemotaxonomic Raman Spectroscopy Investigation of Ascomycetes and Zygomycetes

“…Although the band at 1614 cm −1 was ascribed to the ergosterol peak of the fungal cell walls, 13 its broad features could be ascribed to the chitin peaks. 8 In fact this band at 1614 cm −1 was reportedly quite sensitive to the process of cell divisions. On the other hand, the two broad bands at 1463 and 1356 cm −1 were assigned to the deformation band of methyl groups in phospholipids and the beta glucan peaks of the fungal cell walls, respectively.…”

“…The strong broad band centered at 1579 cm −1 was ascribed to the mixed modes of the amide II and chitin peaks. 8 We checked several points of the samples and found spectral differences between the two fungal species. Despite the broad features, it seems possible to apply Raman spectroscopy for chemotaxonomic identification.…”

“…With the attachment of a microscope, a small number of single spores from fungi can be studied using micro-Raman spectroscopy. 8,9 Previous works on chemotaxonomic identification of fungi have mainly focused on unicellular yeasts. [10][11][12][13][14] In this work we have performed a Raman spectroscopic study of the two different fungal species: ascomycetes and zygomycetes in order to test rapid chemotaxonomic identification by means of a spectroscopic technique.…”

Análisis sobre el crecimiento de hongos en diferentes revestimientos aplicados a sistemas ligeros

“…Microorganisms are essential for biodeterioration and on the production of food and medicine, although many fungi species are pathogenic, impairing health and the economy while contributing to pollution of indoor air and diseases (Ghosal;Macher;Ahmed, 2012). Tham et al (2017) mention that fungi that grow on trees, plants and grass bring about outdoor fungal spores, whereas indoor fungal spores relate to the moisture that lies on furniture.…”

Raman spectroscopy based identification of flame retardants in consumer products using an acquired reference spectral library

“…In particular, access to spatially resolved chemical information without extensive sample preparation or water interference makes the RMS technique appropriate for a variety of sample formats [17,18]. We have previously demonstrated the application of RMS for identifying individual fungal spores [19] as well as FR species in environmental samples [2,3]. Kikuchi et al used Raman spectroscopy for the analysis of brominated FRs in electrical and electronic equipment [4].…”