Year: 2023
Type: article
Abstract: The Center for Nanoscale Systems (CNS) is a core facility and part of the NSF NNCI network. As a multi-user shared facility, we handle samples with varied kinds of history, geometry, dimension, and composition. We have two micro computed tomography (Micro-CT) systems, two ultra-high vacuum X-ray photoelectron spectroscopy (XPS) systems, and one X-ray fluorescence spectroscopy (XRF) system. Our Micro-CTs can perform 3D non-destructive imaging for samples with physical sizes ranging from a few hundred-microns wide up to a meter tall. Research highlights include using Micro-CT to inspect structure-function in helical cardiac musculature development using additive textile manufacturing and the hydraulic implications of rhizomatous growth within plants. A correlated imaging workflow has been developed recently, which allows us to take a macroscopic sample from Micro-CT all the way through FIB to (S)TEM for further high-resolution analysis in details. Our XPS gives us useful chemical and electronic structure analysis on sample material surface. Systems are equipped with both monatomic and cluster argon ion sources, which allows us to perform depth-profiling analysis and surface cleaning with different flexible etching conditions. In addition to XPS analysis, one of our systems can also perform ultraviolet photoelectron spectroscopy (UPS), reflected electron energy loss spectroscopy (REELS), and ion scattering spectroscopy (ISS) analysis, which provide even high surface sensitivity. A few research highlights include using XPS to analyze thin-films, catalysts, quantum materials, energy-related materials, and biomaterial & bio interfaces. Serial-cross section SEM analysis in the focused ion beam (FIB) microscope has become a powerful tool to visualize those intricate structures with nanometer resolution over the entire cell body. Figures 1a and b represent a wild-type parasite inside of a human blood cell at an early and late segmentation stage revealing asynchronous development of various organelles [1]. Knock-down samples, with specific proteins removed, indirectly reveal the role those proteins play in organelle formation, as in the case of P. falciparum, where a previously unknown protein (PfCINCH) was found to be essential in the formation of viable daughter cells (Fig. 1b) [2]. Through correlation with micro-CT, it is possible to target parasites within the context of whole organs. High-resolution X-ray data can provide sufficient resolution to visualize certain cell features which allows here to select specific parasites in the gut of a mosquito, far underneath the sample surface (Fig. 2a,b). We also spent a great deal of time working with geologists, paleontologists, and conservators imaging samples that are physically not possible to examine by other means (Fig. 3) [3]. Plasmodium parasite during early (a) and late stage (b) of cell division inside of a blood cell (not shown) with two representative organelles. The cell wall (semitransparent gray) transforms to a regular set of domes which then pinch off in the center to form daughter cells. (c) A parasite missing the protein PfCINCH produces all organelles (not shown) but is not able to form the proper cell wall envelope to enclose and separate the developing daughter organelles. (a) Semitransparent 3D view of an X-ray data cube of a prepared mosquito gut infested with parasites. The surface was trimmed using the microtome to bring a parasite close to the surface. (b) Representative SEM cross section image. Data segmentation revealed mitochondria (green) to form long networks extending throughout the parasite with a systematic colocalization of their branch endings with nucleoli (blue). A technical study of a head sculpture from Hadda, Afghanistan published with Harvard Art Museums
Source: Microscopy and Microanalysis
Authors: David C Bell, Hao-Yu Greg Lin, Austin Akey, Stephan Kraemer, Jeffrey T Borenstein, Jeffrey D Dvorin, Angela Chang
Institutions: Harvard University, Draper Laboratory, Boston Children's Hospital
Language: English
Subfield: Structural Biology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W4385072437