| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuP |
| Session: | Biomaterial Interfaces Poster Session |
| Presenter: | Xin Hua, Pacific Northwest National Laboratory |
| Authors: | X. Hua, Pacific Northwest National Laboratory C. Szymanski, Pacific Northwest National Laboratory Z. Wang, Pacific Northwest National Laboratory B. Liu, Pacific Northwest National Laboratory Z. Zhu, Pacific Northwest National Laboratory J. Evans, Pacific Northwest National Laboratory G. Orr, Pacific Northwest National Laboratory S. Liu, Southeast University, China X. Yu, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
Mammalian cell analysis is of significant importance in providing detailed insights into biological system activities. Due to the complexity and heterogeneity of mammalian cell behavior and the technical challenge of spatially mapping chemical components in a hydrated environment, correlative chemical imaging from multiplexed measurement platforms is needed. Fluorescence structured illumination microscope (SIM), with super high resolution and visualization of proteins and sub-cellular structures in 3-D, provides more detailed information in cell structure and dynamics. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a unique surface-sensitive tool that provides molecular information and chemical mapping with a sub-micron lateral resolution. However, the understanding of how the spatial heterogeneity and structural difference affect the mammalian cell activities in an unperturbed, hydrated state by ToF-SIMS is severely limited due to the challenge to detect liquids with high volatility in high vacuum using surface sensitive surface techniques.
We recently developed a novel microfluidic reactor enabling correlative imaging of single mammalian cell (e.g., C10 mouse lung epithelial cell) growth by SIM and ToF-SIMS. Cells were introduced in the microchannel, incubated at 37 oC for 24 hr., fed with 5 Nm quantum dots, and then fixed with 4% paraformaldehyde before SIM imaging. In subsequent ToF-SIMS analysis, an aperture of 2 µm in diameter was drilled through the SiN membrane to form a detection window to image biological surfaces directly; and surface tension is used for holding the liquid within the aperture.
SIM images show that cells are successfully cultured on the SiN membrane, and quantum dots are uptaken by cells and dispersed in the cytoplasm. The ToF-SIMS m/z spectra were compared among dried cell samples, hydrated cells, and medium solution. Characteristic lipid fragments are identified. Moreover, 2D mapping of representative cell fragments were obtained. In addition, depth profiling was used to provide time- and space-resolved imaging of the single cell inside the microchannel. Furthermore, principal component analysis is conducted to evaluate the intrinsic similarities and discriminations among samples. Our results demonstrate the feasibility for in situ imaging of single mammalian cells in the hydrated state using ToF-SIMS for the first time. Correlative imaging using SIM and ToF-SIMS provides much sought-after information across different space scales for investigating cell dynamics. This novel approach has great potential for studying intracellular processes in the future.