Imaging and Measuring the Molecular Force of Lymphoma Pathological Cells Using Atomic Force Microscopy

Abstract

Summary: Atomic force microscopy (AFM) provides a new technology to visualize the cellular topography and quantify the molecular interactions at nanometer spatial resolution. In this work, AFM was used to image the cellular topography and measure the molecular force of pathological cells from B-cell lymphoma patients. After the fluorescence staining, cancer cells were recognized by their special morphological features and then the detailed topography was visualized by AFM imaging. The AFM images showed that cancer cells were much rougher than healthy cells. CD20 is a surface marker of B cells and rituximab is a monoclonal antibody against CD20. To measure the CD20-rituximab interaction forces, the polyethylene glycol (PEG) linker was used to link rituximab onto the AFM tip and the verification experiments of the functionalized probe indicated that rituximab molecules were successfully linked onto the AFM tip. The CD20-rituximab interaction forces were measured on about 20 pathological cells and the force measurement results indicated the CD20-rituximab binding forces were mainly in the range of 110-120 pN and 130-140 pN. These results can improve our understanding of the topography and molecular force of lymphoma pathological cells. SCANNING 00: 1-7, 2012. C 2012 Wiley Periodicals, Inc.

Atomic force microscopy study of the antigen‐antibody binding force on patient cancer cells based on ROR1 fluorescence recognition

“…Here we imaged the cellular morphology of cancer cells from patients under the assistance of fluorescence recognition. We have previously used AFM to image the cancer cells assisted by CD20 fluorescence labeling (Li et al ., ), but the disadvantage of this method was that the CD20‐rituximab binding force cannot be measured on the cancer cells after CD20 fluorescence labeling.…”

Nanoscale mapping and organization analysis of target proteins on cancer cells from B-cell lymphoma patients

“…Rituximab was obtained from Chinese Affiliated Hospital of Military Medical Academy of Sciences. The procedure of linking rituximab molecules onto the AFM tips was according to the reference [29,30]. The NHS-PEG3500-MAL (JenKem Technology, Beijing, China) was used as linker molecules.…”

“…The Gaussian fit of the force histograms indicated that the specific binding force (54738 pN) on the cancer cells was distinctly larger than the nonspecific binding force (21719 pN) on the red blood cells. We have previously investigated the CD20-rituximab binding forces on pathological samples [30], but the flaw of the previous researches was that the measurements were blind (we did not know whether the measurements were performed on cancer cells or healthy B cells, and thus the results were elusive). Here under the recognition of ROR1 fluorescence labeling, we can clearly discern the cancer cells and exactly perform the measurements on cancer cells.…”

Progress of AFM single-cell and single-molecule morphology imaging

“…Because of increasingly wider applications of AFM in life sciences, we now have a deeper understanding of physiological activities at the single-cell and single-molecule levels [36][37][38][39][40]. We can now obtain highresolution images of single membrane proteins and observe conformational changes.…”