A Cost-Effective Method to Immobilize Hydrated Soft-Tissue Samples for Atomic Force Microscopy

Abstract

Immobilizing hydrated soft tissue specimens for atomic force microscopy (AFM) is a challenge. Here, we describe a simple and very cost-effective immobilization method, based on the use of transglutaminase in an aqueous environment, and successfully apply it to AFM characterization of human native Wharton's Jelly (nWJ), the gelatinous connective tissue matrix of the umbilical cord. A side-by-side comparison with a widely used polyphenolic protein-based tissue adhesive (Corning Cell-Tak), which is known to bind strongly to virtually all inorganic and organic surfaces in aqueous environments, shows that both adhesives successfully immobilize nWJ in its physological hydrated state. The cost of transglutaminase, however, is over 3000-fold lower than that of Cell-Tak, making it a very attractive method for immobilizing soft tissues for AFM characterization.

Activation of Secretagogue Independent Gastric Acid Secretion via Endothelial Nitric Oxide Synthase Stimulation in Rats

“…Individual gastric glands were dissected from these sections and then transferred in cold Ringer solution to the perfusion chamber. Gastric glands were allowed to adhere to coverslips coated with 0.5µl of the biological adhesive Corning CellTak (Collaborative Research, MA, USA), a widely-used and well known polyphenolic protein-based tissue adhesive, that can strongly bind inorganic as well as organic surfaces in hydrous environment [41]. Accordingly, coverslips were attached to a perfusion chamber as previously outlined [37, 39].…”

Self-assembly of a barnacle cement protein into intertwined amyloid fibres and determination of their adhesive and viscoelastic properties

“…Notably in this study, though adhesion values did not change significantly for the rPpolcp19k-his protein during fibre formation, the values were similar to those measured for Cell-Tak™ (electronic supplementary material, figure S7). Cell-Tak™ is commonly used in comparative investigations of adhesiveness [48,[50][51][52][53] and two phases were detected in its adhesion and modulus in this study, depending on meshwork formation: when Cell-Tak™ formed particles, these exhibited adhesion of 215.74 ± 135.38 pN with a Young's modulus of 0.80 ± 0.12 MPa, whereas adhesion of the meshwork was significantly lower at 62.22 ± 13.10 pN, with an increase in Young's modulus to 2.96 ± 1.29 MPa (electronic supplementary material, figure S7). The normalized adhesion and adhesion energy of Cell-Tak-derived particles were 3.32 ± 2.01 and 0.26 ± 0.16 mJ m −2 , respectively, compared with 0.95 ± 0.10 and 0.07 ± 0.01 mJ m −2 for the protein meshwork.…”

Microindentation of fresh soft biological tissue: A rapid tissue sectioning and mounting protocol

“…Another key component of a successful protocol is that the sectioned tissue needs to be mounted securely for downstream microindentation. As microindentation cannot be performed on unstable samples, the tissue samples should be secured in place so as not to float during testing [ 11 ]. Furthermore, the mounting reagent should be stiffer than the tissue tested, to avoid ambiguity around mechanical results obtained [ 28 ].…”

“…However, detecting these regional differences requires that microindentation takes place within hours of tissue harvest to mitigate the effects of tissue degradation, thereby leading to a number of challenges associated with preparing the tissue for testing [ 8 , 9 ]. The main challenges are the requirement that tissue sectioning and mounting occurs within a limited timeframe before the onset of tissue degradation [ 10 , 11 ].…”