| AVS 59th Annual International Symposium and Exhibition | |
| In Situ Microscopy and Spectroscopy Focus Topic | Tuesday Sessions |
| Session IS+AS+BI+ET+GR+NS-TuA |
| Session: | In Situ Studies of Organic and Soft Materials and In Situ Microscopy |
| Presenter: | L. Yang, Pacific Northwest National Laboratory |
| Authors: | L. Yang, Pacific Northwest National Laboratory X.-Y. Yu, Pacific Northwest National Laboratory Z. Zhu, Pacific Northwest National Laboratory S. Thevuthasan, Pacific Northwest National Laboratory J. Cowin, Cowin In-Situ Science, L. L. C. |
| Correspondent: | Click to Email |
A vacuum compatible microfluidic interface was developed to enable surface analysis of liquids. The unique feature of the liquid flow cell is that the detection window is open to the vacuum allowing direct probing of the liquid surface. The flow cell is composed of a silicon nitride membrane and polydimethylsiloxane; and it is fully compatible with vacuum operations for surface analysis. The aperture can be drilled through the 100 nm silicon nitride membrane by using the focused ion beam/scanning electron microscope (FIB/SEM). Alternatively the primary Bi+ ions in ToF-SIMS can be used to fabricate the aperture window in real-time. New results using this vacuum interface and recent development will be presented in this paper. Several aqueous solutions containing conjugated IgG gold nanoparticles and representative biological solutions were studied in situ using scanning electron microscope (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Characteristic signals of the conjugated gold nanoparticles were successfully observed through the aperture by both energy-dispersive X-ray spectroscopy (EDX) in SEM and ToF-SIMS. Comparisons were also made among wet and dry samples and liquid sample in the flow cell using SEM/EDX. Stronger gold signal can be observed in our novel portable device by SEM/EDX compared with the wet or dry samples, respectively. Our results indicate that analyses of the nanoparticle conjugated antibodies are better made in their native liquid environment. Our unique microfluidic flow cell permits in situ liquid observations. In addition, a variety of aqueous solutions relevant to biological systems were analyzed. Our results indicate that chemical imaging by SEM and ToF-SIMS is applicable in analyzing more complicated aqueous solutions when coupled with our novel portable microfluidic platform.