High-performance imaging of cell-substrate contacts using refractive index quantification microscopy.

Ziqiang Xin,Yijia Wang,Chonglei Zhang,Min Wang,Xiaocong Yuan,Chao Wan,Lixun Sun,Siwei Zhu,Houkai Chen,Ting Chen

doi:10.1364/boe.409764

Abstract

Non-invasive imaging of living cells is an advanced technique that is widely used in the life sciences and medical research. We demonstrate a refractive index quantification microscopy (RIQM) that enables label-free studies of glioma cell-substrate contacts involving cell adhesion molecules and the extracellular matrix. This microscopy takes advantage of the smallest available spot created when an azimuthally polarized perfect optical vortex beam (POV) is tightly focused with a first-order spiral phase, which results in a relatively high imaging resolution among biosensors. A high refractive index (RI) resolution enables the RI distribution within neuronal cells to be monitored. The microscopy shows excellent capability for recognizing cellular structures and activities, demonstrating great potential in biological sensing and live-cell kinetic imaging.

Highlights

Cell adhesion (CA) and the extracellular matrix (ECM) are both important for cell growth, migration, communication, and regulation
refractive index (RI) imaging of U-87 MG human neuroglioma cells was carried out in this study and mosaic RI images of two cells are presented in Fig. 5(a5) and Fig. 5(b4)
The consistency of the images obtained using each method demonstrates that the RI imaging technique reveals the true cellular morphology and that the point-scan imaging mechanism does not introduce aberrations

Summary

Introduction

Cell adhesion (CA) and the extracellular matrix (ECM) are both important for cell growth, migration, communication, and regulation. The ECM plays a vital role in synaptic remodeling of active neurons, which is essential for memory formation [1]. Events occurring at the cell-substrate interface affect CA and ECM behaviors significantly and the ability to observe the localization and real-time activity of these events plays an important role in biological studies [6]. Due to the capacity of effective background noise suppression, total internal refection fluorescence microscopy (TIRFM) has emerged that provides clear fluorescence images within evanescent field and appears to be a promising tool for the study of cell-substrate contacts [9,10]. It is sometimes undesirable to stain the cells of interest in certain applications (e.g. stem cell and fertility studies, neurotransmitter and conduction studies) [13], and the process of staining with multiple fluorophores can be challenging

Methods

Results

Conclusion