Surface-Sensitive Imaging Analysis of Cell–Microenvironment Interactions by Electrochemiluminescence Microscopy

Abstract

A complex and heterogeneous cell microenvironment offers not only structural support for cells but also myriad biochemical and biophysical cues. These outside-in signals transmit into cells primarily through integrins, which are the important components of cell–matrix adhesions to direct and maintain cell behaviors and fate. In this work, we report a surface-sensitive imaging methodology for evaluating the difference in cell–matrix adhesions at the single cell level to dissect the impact of the chemical microenvironment on cell behaviors. Cells were cultured on silica nanochannel membrane (SNM) modified indium tin oxide (ITO) electrodes (SNM/ITO) with different terminal surfaces and imaged by electrochemiluminescence microscopy (ECLM). The results show that the surface tethered with Arg-Gly-Asp (RGD) groups can mediate robust cell–microenvironment interaction and those coated with silanol and (3-aminopropyl)­triethoxysilane (APTES) groups transmit an intermediate adhesion, while oligo­(ethylene glycol) (OEG) coated surface conveys the weakest cell–matrix adhesion. Specific recognition of integrins to different surfaces was further explored in conjunction with selective immunoblocking of different subunits. α6, α5, and α1 integrin subunits were found to recognize SNM, RGD/OEG, and APTES surfaces, respectively. The work provides not only insights into cell–microenvironment interaction but also guideline in the design and development of functional and biomimetic surface materials.

A Close Look at Mechanism, Application, and Opportunities of Electrochemiluminescence Microscopy

“…Thus, they later changed the terminal groups tethered on SNM/ITO to explore the specific recognition of integrins to different surfaces. Through the morphology change of cell adhesion, it was found that α6, α5, and α1 subunits sensed SNM, RGD/OEG, and APTES electrode surfaces, respectively . Gao et al then observed the process of cell shrinking, crumpling, and detaching from the electrode surface by adding H 2 O 2 , along with the cell aggregation by electrical stimulation.…”

Recent advances in label-free imaging of cell–matrix adhesions

“…44 Further modifying the SNM rich in silanol groups with Arg-Gly-Asp (RGD), (3-aminopropyl)triethoxysilane (APTES), and oligo(ethylene glycol) (OEG), the influence of chemical microenvironments on cell behaviors was evaluated by imaging the cell-matrix adhesions. 46 The statistical analysis of spatial distribution, area and strength of adhesions shows that the surfaces tethered with RGD and OEG groups can mediate the robust and weakest cell-microenvironment interactions, respectively, and that an intermediate adhesion is distributed on the APTES-coated surface. Moreover, in conjunction with selective immune-blocking of different integrin subunits, a 6 , a 5 , and a 1 subunits are found to function in recognizing SNM, RGD/OEG and APTES surfaces, respectively.…”

Imaging of Single Bacteria with Electrochemiluminescence Microscopy

“…15,16 ECL microscopy has been used for imaging of cell membranes, 17,18 cell adhesion, 19,20 cell−cell junctions, 21 and the interactions between cells and the surrounding microenvironment. 22 Sojic's group recently developed shadow ECL microscopy for imaging single mitochondria, 23 which is the smallest biological object imaged by conventional ECL microscopy. However, revealing different types of biological samples, such as bacteria for identification and uncovering their specific features at the nanoscale with ECL microscopy, remains challenging.…”

“…Electrochemiluminescence (ECL) is a light emission process that is turned on by electrochemical reactions. , This process has attracted increasing attention for bioimaging at the single cell level because of its low background, high sensitivity, and ability to provide unique information on chemical characteristics such as local chemical activity in addition to spatial information. , ECL microscopy has been used for imaging of cell membranes, , cell adhesion, , cell–cell junctions, and the interactions between cells and the surrounding microenvironment . Sojic’s group recently developed shadow ECL microscopy for imaging single mitochondria, which is the smallest biological object imaged by conventional ECL microscopy.…”