AFM‐based nanomechanical characterization of bronchoscopic samples in asthma patients

Abstract

Asthma is not a single disease, but recently, it is considered as a syndrome characterized through various clinical presentations and different etiopathologies. Large degree of the disease heterogeneity manifests in distinct characteristics that translate into variability of properties at single cell and molecular levels. Here, we conducted measurements of mechanical properties of bronchial tissue samples collected from patients suffering from asthma. The results obtained from different applied protocols for sample preparation may indicate that deep freezing and storage in liquid nitrogen, followed by consecutive unfreezing of tissue samples, preserve tissue mechanical properties as indicated by a parameter referred here as a tissue relative stiffness index. Tissue relative stiffness index quantifies both the degree of heterogeneity and deformability of tissue samples regarding healthy one. These studies demonstrate that the freezing protocol, optimized towards asthma tissue, can facilitate atomic force microscopy use what, together with recent findings on standardization of elasticity measurements, enables the measurements of large group of samples with minimized influence of errors stemming from the applied methodology of tissue stiffness determination.

Nano-scientific Application of Atomic Force Microscopy in Pathology: from Molecules to Tissues

“…It is also fascinating that AFM studies have also reported close correlation between inflammatory diseases, such as asthma, and the mechanical softening of tissues [47,50]. The mechanosensitive production of insulin from islets was confirmed by AFM-based nano-indentation experiments performed on transgenic DORmO mouse model of type 1 diabetes [50].…”

“…For example, erythrocyte cells were isolated from blood samples in order to investigate hereditary spherocytosis, iron deficiency anemia, sickle cell disease, and type 2 diabetes using AFM [27,[42][43][44][45][46]. In addition, it is relatively easy to obtain tissue samples from asthma patients for AFM studies because bronchial tissues can be collected through routine bronchoscopy [47]. However, studies on some diseases require more painful procedures for specimen collection.…”

“…Some attempts were made to obtain both the storage and loss moduli of biological samples by superimposing the oscillating motion on the probe while indenting the samples [113,115,119]. For the clinical applications of AFM techniques, there have been an increasing number of studies investigating tissues obtained from a minimally invasive surgical intervention such as biopsy [47,50,120]. One of the long-standing problems associated with probing tissues, in comparison with cells, is the technical difficulty associated with immobilizing tissue samples on hard substrates in liquid environments.…”

“…Nanopillars of "bed of nails"-like approach to anchor pancreatic islet demonstrates an exemplary strategy to achieve proper immobilization of tissues [50]. In addition, comparative studies that evaluated changes in elastic moduli with regards to storage and buffer conditions have been carried out to establish the standard conditions for AFM nano-mechanical studies on tissues [47]. Table 2 summarizes AFM-based bio-mechanical reports on changes in elastic moduli attributed to disease onset and progression.…”

Fifteen years of Servitude et Grandeur to the application of a biophysical technique in medicine: The tale of AFMBioMed

“…A virtual issue appeared in the Journal of Molecular Recognition and is linked with this editorial. Ten research articles composed this special issue Pleskova S. N., Gorshkova E. N., and Kriukov R. N. Dynamics of formation and morphological features of neutrophil extracellular traps formed under the influence of opsonized Staphylococcus aureus .…”