Multi-resolution correlative ultrastructural and chemical analysis of carious enamel by scanning microscopy and tomographic imaging

DOI: 10.1021/acsami.3c08031

Authors: Cyril Besnard (University of Oxford) , Ali Marie (University of Oxford) , Sisini Sasidharan (University of Oxford) , Petr Buček (TESCAN-UK Ltd) , Jessica M. Walker (Diamond Light Source) , Julia E. Parker (Diamond Light Source) , Matthew C. Spink (Diamond Light Source) , Robert A. Harper (University of Birmingham) , Shashidhara Marathe (Diamond Light Source) , Kaz Wanelik (Diamond Light Source) , Thomas E. J. Moxham (University of Oxford; Diamond Light Source) , Enrico Salvati (University of Oxford) , Konstantin Ignatyev (Diamond Light Source) , Michal M. Klosowski (Research Complex at Harwell) , Richard M. Shelton (University of Birmingham) , Gabriel Landini (University of Birmingham) , Alexander M. Korsunsky (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Materials & Interfaces , VOL 10

State: Published (Approved)
Published: July 2023
Diamond Proposal Number(s): 27749 , 30684 , 30691 , 31005 , 29256 , 23873

Abstract: Caries, a major global disease associated with dental enamel demineralization, remains insufficiently understood to devise effective prevention or minimally invasive treatment. Understanding the ultrastructural changes in enamel is hampered by a lack of nanoscale characterization of the chemical spatial distributions within the dental tissue. This leads to the requirement to develop techniques based on various characterization methods. The purpose of the present study is to demonstrate the strength of analytic methods using a correlative technique on a single sample of human dental enamel as a specific case study to test the accuracy of techniques to compare regions in enamel. The science of the different techniques is integrated to genuinely study the enamel. The hierarchical structures within carious tissue were mapped using the combination of focused ion beam scanning electron microscopy with synchrotron X-ray tomography. The chemical changes were studied using scanning X-ray fluorescence (XRF) and X-ray wide-angle and small-angle scattering using a beam size below 80 nm for ångström and nanometer length scales. The analysis of XRF intensity gradients revealed subtle variations of Ca intensity in carious samples in comparison with those of normal mature enamel. In addition, the pathways for enamel rod demineralization were studied using X-ray ptychography. The results show the chemical and structural modification in carious enamel with differing locations. These results reinforce the need for multi-modal approaches to nanoscale analysis in complex hierarchically structured materials to interpret the changes of materials. The approach establishes a meticulous correlative characterization platform for the analysis of biomineralized tissues at the nanoscale, which adds confidence in the interpretation of the results and time-saving imaging techniques. The protocol demonstrated here using the dental tissue sample can be applied to other samples for statistical study and the investigation of nanoscale structural changes. The information gathered from the combination of methods could not be obtained with traditional individual techniques.

Journal Keywords: human carious enamel; synchrotron spectroscopy; nano-X-ray fluorescence spectroscopy; nanodiffraction; ptychography; FIB-SEM; tomography

Subject Areas: Biology and Bio-materials, Technique Development, Materials

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: E01-JEM ARM 200CF , I08-1-Soft X-ray Ptychography , I13-2-Diamond Manchester Imaging , I14-Hard X-ray Nanoprobe , I18-Microfocus Spectroscopy

Added On: 02/08/2023 08:48

Discipline Tags:

Technique Development - Materials Science Dentistry Health & Wellbeing Materials Science Nanoscience/Nanotechnology Life Sciences & Biotech

Technical Tags:

Imaging Microscopy Coherent Diffraction Imaging (CDI) Tomography X-ray Fluorescence (XRF) Ptychography Electron Microscopy (EM) X-ray Microscopy Scanning Electron Microscopy (SEM) Scanning X-ray Microscopy Soft X-ray Ptychography