Self-Assembled Monolayers of an Azobenzene Derivative on Silica and Their Interactions with Lysozyme

Abstract

The capability of the photoresponsive isomerization of azobenzene derivatives in self-assembled monolayer (SAM) surfaces to control protein adsorption behavior has very promising applications in antifouling materials and biotechnology. In this study, we performed an atomistic molecular dynamics (MD) simulation in combination with free-energy calculations to study the morphology of azobenzene-terminated SAMs (Azo-SAMs) grafted on a silica substrate and their interactions with lysozyme. Results show that the Azo-SAM surface morphology and the terminal benzene rings' packing are highly correlated with the surface density and the isomer state. Higher surface coverage and the trans-isomer state lead to a more ordered polycrystalline backbone as well as more ordered local packing of benzene rings. On the Azo-SAM surface, water retains a high interfacial diffusivity, whereas the adsorbed lysozyme is found to have extremely low mobility but a relative stable secondary structure. The moderate desorption free energy (∼60 kT) from the trans-Azo-SAM surface was estimated by using both the nonequilibrium-theorem-based Jarzynski's equality and equilibrium umbrella sampling.

Lysozyme Adsorption on Different Functionalized MXenes: A Multiscale Simulation Study

“…In previous simulation studies, the protein must overcome the interfacial hydration layer and then adsorb onto different surfaces, such as polyethylene, , graphene, SAM, , etc., which is the so-called dehydration. Wei et al ,, demonstrated the significant role of the dehydration process on a hydrophobic surface.…”

“…In previous simulation studies, the protein must overcome the interfacial hydration layer and then adsorb onto different surfaces, such as polyethylene, , graphene, SAM, , etc., which is the so-called dehydration. Wei et al ,, demonstrated the significant role of the dehydration process on a hydrophobic surface. But for the highly hydrophilic surfaces like TiO 2 , the protein may only have a small number of residues that can be inserted into the internal water layer and have a certain strong interaction with the surface, causing weak adsorption, because it needs to overcome the large dehydration energy barrier.…”

Airborne Transmission of COVID-19: Aerosol Dispersion, Lung Deposition, and Virus-Receptor Interactions

“…Computer simulations, such as atomistic molecular dynamics (MD), − have become a crucial approach to complement experimental studies and provide insight into the structural dynamics of the S protein and its interactions with ligands. Atomistic MD simulations compute trajectories and positions of N interacting atoms in a system by numerically solving Newton’s equations of motion. , Simulations can probe molecular structures with atomistic resolutions and sample MD from subnanoseconds to microseconds and elucidate molecular interactions. − ,− …”

Advances in Application of Azobenzene as a Trigger in Biomedicine: Molecular Design and Spontaneous Assembly

“…Shing and co‐workers [ 248 ] conducted an atomistic molecular dynamics (MD) simulation to show that the ability of azobenzene‐terminated SAMs (Azo‐SAMs) grafted on a silica substrate to adsorb lysozyme was affected by the cis – trans configuration of the azo group. Calculations indicated that the lysozyme adsorbed on the high‐density trans ‐Azo‐SAM surface has a desorption free energy of about 60kT.…”