Organic self-assembled monolayers for reconstitution of ion channels on single crystal silicon

The major goal of this research is to understand design principles of interfaces, suitable for the reconstitution the ion channel membrane proteins. In the present work, we focused on the immobilization of two channel proteins, α-Hemolysin from Staphylococcus aureus and Mechanosensitive Ion Channel of Large Conductance (MscL) from Salmonella typhimurium, onto single crystal silicon substrates (silicon wafers). High-resolution atomic force microscopy (AFM) was utilized as a tool for the monitoring of the molecular conformations of the ion channels after immobilization. As observed, α-Hemolysin was adsorbed onto bare silicon in collapsed state, while adsorption of MscL resulted in unraveling of the protein. LB deposition of proteins embedded in lipid monolayer reduced denaturation of the proteins on silicon surface, due to reduced surface energy. Octadecyltimethoxy silane (ODTMS) self-assembled monolayers (SAMs) were used as a buffer layer analog of a lipid membrane. MscL was successfully reconstituted in these organic SAMs. Analysis of dimensions of the MscL displayed that the gating state and the molecular conformation of SAM-supported MscL can be controlled by variation of the surface energy of the supporting surface layer. Closed, intermediate, and open states were observed on surfaces with different surface tensions. Obtained results demonstrated an agreement with known molecular modeling data for gating mechanisms of the MscL protein in lipid membrane

Synthetic and bio-hybrid nanoscale layers with tailored surface functionalities

Abstract We examine the prospective routes for the design of synthetic/biomacromolecular/inorganic film assemblies for photothermal cell based on biomimetic approach. We demonstrate examples of channel proteins immobilized onto surfaces of silicon single crystals modified with Langmuir-Blodgett and self-assembled monolayers. These proteins can be immobilized in intact, closed-pore conformation. Their state within photosensitive monolayers can be controlled by the photoisomerization reaction triggered by UV light

Shell design of functional hyperbranched molecules for surface assembly

This study explores possibilities of obtaining of unique self-assembled, nanofibrillar structures from amphiphilic hyperbranched molecules on solid surfaces. To achieve this, we explore the multifunctional properties of hyperbranched polymers which are determined by the nature of the end groups and structure of the chemical composition of the core unit. We established that the combination of hydrophobic interactions and multiple hydrogen bonding events added to the dendritic core structure is responsible for stable assembling into nanofibrillar morphology at the air-water interface at both the nano and at microscales and determined compositional boundaries of this phenomenon;The core-shell architecture of the amphiphilic dendritic molecules suggested here provides exceptional stability of one-dimensional nanofibrillar structures. The critical condition for the formation of the nanofibrillar structures is the presence of both alkyl tails in the outer shell as the hydrophobic component and either amine or carboxyl groups in the shell as the hydrophilic component. The multiple intermolecular hydrogen bonding and polar interactions between flexible cores stabilize these nanofibers and make them robust against surface pressure and solvents. Moreover, discovered assembled nano-fibers formed by hyperbranched polymers have been used for templating of silver nanoparticles via growth from water subphase. We observed that hyperbranched polymers scaffolds can create aligned nanoparticle arrays, and also effectively control size of the particles to about 3 nm.</p

Organic self-assembled monolayers for reconstitution of ion channels on single crystal silicon

"The major goal of this research is to understand design principles of interfaces, suitable for the reconstitution the ion channel membrane proteins. In the present work, we focused on the immobilization of two channel proteins, α-Hemolysin from Staphylococcus aureus and Mechanosensitive Ion Channel of Large Conductance (MscL) from Salmonella typhimurium, onto single crystal silicon substrates (silicon wafers). High-resolution atomic force microscopy (AFM) was utilized as a tool for the monitoring of the molecular conformations of the ion channels after immobilization. As observed, α-Hemolysin was adsorbed onto bare silicon in collapsed state, while adsorption of MscL resulted in unraveling of the protein. LB deposition of proteins embedded in lipid monolayer reduced denaturation of the proteins on silicon surface, due to reduced surface energy. Octadecyltimethoxy silane (ODTMS) self-assembled monolayers (SAMs) were used as a ""buffer layer analog"" of a lipid membrane. MscL was successfully reconstituted in these organic SAMs. Analysis of dimensions of the MscL displayed that the gating state and the molecular conformation of SAM-supported MscL can be controlled by variation of the surface energy of the supporting surface layer. Closed, intermediate, and open states were observed on surfaces with different surface tensions. Obtained results demonstrated an agreement with known molecular modeling data for gating mechanisms of the MscL protein in lipid membrane."</p