Degradation of alkanethiol self‐assembled monolayers in mesenchymal stem cell culture

Abstract

Alkanethiol self-assembled monolayers (SAMs) have been used extensively in studying the role of surface functionality and geometry on stem cell differentiation; however, the effects of stem cell culture conditions on SAM stability over time are not well understood. In this work, we examined the physical and chemical changes occurring on gold (Au)-SAM surfaces over time as a function of Au thickness. Within a narrow range of thicknesses (4, 8, and 10 nm), we observed significant differences in temporal SAM stability for a commonly utilized, hydrophilic, protein and cell repulsive oligo(ethylene) glycol alkanethiol (HS-(CH ) (O(CH ) ) OH) SAM and the hydrophobic, protein adhesive hexadecanethiol (SH-(CH ) CH ) SAM. Within both acellular and stem cell culture conditions, 8 nm Au resulted in the most stable SAMs (∼7 days). The 4 and 10 nm Au SAMs exhibited loss in stability following 5 days at varying degradation rates, showing 4 nm Au to be the least stable. Migration of human mesenchymal stem cells seeded on SAM surfaces showed that SAM degradation rates in acellular conditions were directly correlated with the cellular migration behavior. Findings of this study can be used to develop SAM surfaces with controlled degradation rates for applications in stem cell engineering and regenerative medicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 464-474, 2017.

Hysteretic Swelling/Deswelling of Polyelectrolyte Brushes and Bilayer Films in Response to Changes in pH and Salt Concentration

“…Gold-coated silicon wafers were plasma treated before use. As described previously [ 19 ], we dissolved short-chain PAA-SH (M n : 2000 g/mol, M w /M n = 1.3) in absolute ethanol to a final concentration of 4 mM [ 22 ]. The 4 mM PAA solution was used both as is and after dilution in either absolute ethanol or a 10:1 (wt%) mixture of absolute ethanol to 2-mercaptoethanol, where the latter is a competitive adsorbent to compete with the PAA-SH in binding to the gold-coated QCM-D crystal, thereby controlling grafting density.…”

Mixed‐monolayer of N‐hydroxysuccinimide‐terminated cross‐linker and short alkanethiol to improve the efficiency of biomolecule binding for biosensing

“…Due to several advantages offered, SAMs are preferred for functionalization of surfaces. In addition to their spontaneous and controllable formation in an oriented manner, they are easily characterized by contact angle measurements and various spectroscopic tools . mSAMs generated by attachment of two different molecules increases the functionality of the surface by bringing together the chemical structure properties of two components in one platform .…”

“…has become an important task for the development of biosensing platforms . SAMs generated by the adsorption of organosulfur compounds such as alkanethiols, dialkyldisulfides, and dialkyl sulfides on gold has gained attention in many fields including biosensor applications . Due to several advantages offered, SAMs are preferred for functionalization of surfaces.…”

“…formation in an oriented manner, [3][4][5] they are easily characterized by contact angle measurements and various spectroscopic tools. 5,9,[13][14][15][16][17] mSAMs generated by attachment of two different molecules increases the functionality of the surface by bringing together the chemical structure properties of two components in one platform.…”

Tuning RGD Motif and Hyaluronan Density to Study Integrin Binding

“…Alkanethiols terminated with oligo(ethylene glycol) moieties (OEG-alkanethiols) form SAMs on gold surfaces, which are resistant to unspecific protein adsorption. These surfaces have been exploited in several studies including cell adhesion or stem cell differentiation ( Tidwell et al, 1997 ; Arima and Iwata, 2015 ; Hao et al, 2016 ; Almeida and Shukla, 2017 ).…”