TY - JOUR
T1 - Label-Free Imaging of Nanoscale Displacements and Free-Energy Profiles of Focal Adhesions with Plasmonic Scattering Microscopy
AU - Zhang, Pengfei
AU - Zhou, Xinyu
AU - Wang, Rui
AU - Jiang, Jiapei
AU - Wan, Zijian
AU - Wang, Shaopeng
N1 - Funding Information:
We thank financial support from National Institutes of Health (R01GM107165). We acknowledge the use of facilities within the ASU NanoFab supported in part by the NSF program NNCI-ECCS-1542160.
Publisher Copyright:
©
PY - 2021/11/26
Y1 - 2021/11/26
N2 - Cell adhesion plays a critical role in cell communication, cell migration, cell proliferation, and integration of medical implants with tissues. Focal adhesions physically link the cell cytoskeleton to the extracellular matrix, but it remains challenging to image single focal adhesions directly. Here, we show that plasmonic scattering microscopy (PSM) can directly image the single focal adhesions in a label-free, real-time, and non-invasive manner with sub-micrometer spatial resolution. PSM is developed based on surface plasmon resonance (SPR) microscopy, and the evanescent illumination makes it immune to the interference of intracellular structures. Unlike the conventional SPR microscopy, PSM can provide a high signal-to-noise ratio and sub-micrometer spatial resolution for imaging the analytes with size down to a single-molecule level, thus allowing both the super-resolution lateral localization for measuring the nanoscale displacement and precise tracking of vertical distances between the analyte centroid and the sensor surface for analysis of free-energy profiles. PSM imaging of the RBL-2H3 cell with temporal resolution down to microseconds shows that the focal adhesions have random diffusion behaviors in addition to their directional movements during the antibody-mediated activation process. The free-energy mapping also shows a similar movement tendency, indicating that the cell may change its morphology upon varying the binding conditions of adhesive structures. PSM provides insights into the individual focal adhesion activities and can also serve as a promising tool for investigating the cell/surface interactions, such as cell capture and detection and tissue adhesive materials screening.
AB - Cell adhesion plays a critical role in cell communication, cell migration, cell proliferation, and integration of medical implants with tissues. Focal adhesions physically link the cell cytoskeleton to the extracellular matrix, but it remains challenging to image single focal adhesions directly. Here, we show that plasmonic scattering microscopy (PSM) can directly image the single focal adhesions in a label-free, real-time, and non-invasive manner with sub-micrometer spatial resolution. PSM is developed based on surface plasmon resonance (SPR) microscopy, and the evanescent illumination makes it immune to the interference of intracellular structures. Unlike the conventional SPR microscopy, PSM can provide a high signal-to-noise ratio and sub-micrometer spatial resolution for imaging the analytes with size down to a single-molecule level, thus allowing both the super-resolution lateral localization for measuring the nanoscale displacement and precise tracking of vertical distances between the analyte centroid and the sensor surface for analysis of free-energy profiles. PSM imaging of the RBL-2H3 cell with temporal resolution down to microseconds shows that the focal adhesions have random diffusion behaviors in addition to their directional movements during the antibody-mediated activation process. The free-energy mapping also shows a similar movement tendency, indicating that the cell may change its morphology upon varying the binding conditions of adhesive structures. PSM provides insights into the individual focal adhesion activities and can also serve as a promising tool for investigating the cell/surface interactions, such as cell capture and detection and tissue adhesive materials screening.
KW - cell physiology
KW - plasma membrane
KW - plasmonic scattering microscopy
KW - surface interactions
KW - surface plasmon resonance
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U2 - 10.1021/acssensors.1c01938
DO - 10.1021/acssensors.1c01938
M3 - Article
C2 - 34711049
AN - SCOPUS:85118986272
VL - 6
SP - 4244
EP - 4254
JO - ACS Sensors
JF - ACS Sensors
SN - 2379-3694
IS - 11
ER -