Effect of Surface Potential on Extracellular Matrix Protein Adsorption

Abstract

Extracellular matrix (ECM) proteins, such as fibronectin, laminin, and collagen IV, play important roles in many cellular behaviors, including cell adhesion and spreading. Understanding their adsorption behavior on surfaces with different natures is helpful for studying the cellular responses to environments. By tailoring the chemical composition in binary acidic (anionic) and basic (cationic) functionalized self-assembled monolayer (SAM)-modified gold substrates, variable surface potentials can be generated. To examine how surface potential affects the interaction between ECM proteins and substrates, a quartz crystal microbalance with dissipation detection (QCM-D) was used. To study the interaction under physiological conditions, the ionic strength and pH were controlled using phosphate-buffered saline at 37 °C, and the ζ potentials of the SAM-modified Au and protein were determined using an electrokinetic analyzer and phase analysis light scattering, respectively. During adsorption processes, the shifts in resonant frequency (f) and energy dissipation (D) were acquired simultaneously, and the weight change was calculated using the Kelvin-Voigt model. The results reveal that slightly charged protein can be adsorbed on a highly charged SAM, even where both surfaces are negatively charged. This behavior is attributed to the highly charged SAM, which polarizes the protein microscopically, and the Debye interaction, as well as other short-range interactions such as steric force, hydrogen bonding, direct bonding, charged domains within the protein structure, etc., that allow adsorption, although the macroscopic electrostatic interaction discourages adsorption. For surfaces with a moderate potential, proteins are not significantly polarized by the surface, and the interaction can be predicted through simple electrostatic attraction. Furthermore, surface-induced self-assembly of protein molecules also affects the adsorbed structures and kinetics. The adsorbed layer properties, such as rigidity and packing behaviors, were further investigated using the D-f plot and phase detection microscopy (PDM) imaging.

Protein-crystal interface mediates cell adhesion and proangiogenic secretion

“…Previous work by You et al shows that the amount of Fn adsorbed increased with increasing surface charge density of self-assembled monolayers within a range of −28 to −121 mV, and decreased at even higher surface charge density. Their work implies that, within such range of surface charge density, microscopic polarization rather than macroscopic electrostatic repulsion plays a dominant role in Fn adsorption [56]. Although the polarization effect is weaker on micro-rough facets due to lower surface charge density, lower electrostatic repulsion combined with higher probability of mechanical entrapment of Fn molecules within surface features can lead to higher Fn adsorption onto micro-rough facets than onto their nano-rough counterparts.…”

Surface chemistry regulates valvular interstitial cell differentiation in vitro

“…[37, 38, 42, 43] In previous work, it has been observed that proteins in culture adsorb at a faster rate than cell attachment, and dictate cell-surface interactions. [38, 44] Specifically the adsorption of proteins to hydrophobic/hydrophilic and charged surfaces has shown that specific extracellular matrix proteins bind in a surface dependent manner, with variability in their tertiary structure, resulting in variation in available cellular attachment domains.…”

“…[38, 44] Specifically the adsorption of proteins to hydrophobic/hydrophilic and charged surfaces has shown that specific extracellular matrix proteins bind in a surface dependent manner, with variability in their tertiary structure, resulting in variation in available cellular attachment domains. [37–39, 43, 45]…”

“…NH 3 + -SAMs have been shown to preferentially adsorb greater amounts collagen and fibronectin than other hydrophilic groups (COO − and OH). [43] However, currently literature on the influence of collagen and fibronectin on VIC nodule formation is conflicting. [10, 18–20] These differences may be due to differences in processing of the extracellular matrix proteins in these studies.…”

The Role of Acellular Flowable Matrix in Tissue Regeneration

“…Understanding their adsorption behavior on surfaces with different natures is helpful for studying the cellular responses to environments. [11] Various polymers, including natural, synthetic and natural/synthetic hybrid polymers, have been used to make hydrogels via chemical or physical crosslinking. Recently, bioactive synthetic hydrogels have emerged as promising scaffolds because they can provide molecularly tailored biofunctions and adjustable mechanical properties, as well as an extracellular matrix-like microenvironment for cell growth and tissue formation.…”