Functional Modification of Silica through Enhanced Adsorption of Elastin-Like Polypeptide Block Copolymers

Abstract

A powerful tool for controlling interfacial properties and molecular architecture relies on the tailored adsorption of stimuli-responsive block copolymers onto surfaces. Here, we use computational and experimental approaches to investigate the adsorption behavior of thermally responsive polypeptide block copolymers (elastin-like polypeptides, ELPs) onto silica surfaces, and to explore the effects of surface affinity and micellization on the adsorption kinetics and the resultant polypeptide layers. We demonstrate that genetic incorporation of a silica-binding peptide (silaffin R5) results in enhanced adsorption of these block copolymers onto silica surfaces as measured by quartz crystal microbalance and ellipsometry. We find that the silaffin peptide can also direct micelle adsorption, leading to close-packed micellar arrangements that are distinct from the sparse, patchy arrangements observed for ELP micelles lacking a silaffin tag, as evidenced by atomic force microscopy measurements. These experimental findings are consistent with results of dissipative particle dynamics simulations. Wettability measurements suggest that surface immobilization hampers the temperature-dependent conformational change of ELP micelles, while adsorbed ELP unimers (i.e., unmicellized block copolymers) retain their thermally responsive property at interfaces. These observations provide guidance on the use of ELP block copolymers as building blocks for fabricating smart surfaces and interfaces with programmable architecture and functionality.

Engineering the Architecture of Elastin‐Like Polypeptides: From Unimers to Hierarchical Self‐Assembly

“…López and colleagues reported the synthesis of near‐monodisperse, discrete hybrid ELP‐silica particles by inducing a silification reaction on the micellar corona . A silicon affinity domain from lysine‐rich silaffin R5 peptide was fused with the hydrophilic N‐terminus of a diblock ELP .…”

“…Cryo‐TEM images showed solid particles packed in a near‐hexagonal lattice . Similar ELP‐silica conjugates have been developed for drug delivery and for functional modification of silica surfaces …”

Quantifying Thermoswitchable Carbohydrate‐Mediated Interactions via Soft Colloidal Probe Adhesion Studies

“…[ 1,2 ] Stimuli responsive polymers that enable the remote activation or deactivation of specific ligand–receptor interactions are being developed to facilitate site specific drug carriers, externally controlled binding to proteins, or capture/release of pathogens. [ 3–9 ] Most of these systems rely on thermoresponsive polymers undergoing a coil‐to‐globule transition in the physiological temperature range, thereby shifting the affinity of linked biomolecules, e.g., by varying their accessibility to control their specific binding. Thermoresponsive polymers with a lower critical solution temperature (LCST) between 30 and 40 °C are most frequently used for such applications, where poly( N ‐isopropyl acrylamide) (PNIPAM), poly( N ‐vinyl caprolactam) or poly(oligoethylene glycols) are well‐known examples.…”

A thermo-responsive, self-assembling biointerface for on demand release of surface-immobilised proteins

“…13 Protein conformational switches can present on/off biomolecular recognition ability that can be triggered to release or capture another protein on demand, in response to external stimuli such as ion concentration 14 or temperature. [15][16][17] Protein conformational switches are particularly relevant for the design of switchable surfaces and interfaces with programmable functionalities. 16 Smart and functional materials that can be switched remotely will be increasingly used in applications beyond drug delivery and they have been already applied to control cell adhesion, 18 assemble nanomaterials on surfaces, 19 control biomolecular interactions for analytical devices 15 and set the on/off state of bio-valves between catalytic nanoscale compartments.…”

“…[15][16][17] Protein conformational switches are particularly relevant for the design of switchable surfaces and interfaces with programmable functionalities. 16 Smart and functional materials that can be switched remotely will be increasingly used in applications beyond drug delivery and they have been already applied to control cell adhesion, 18 assemble nanomaterials on surfaces, 19 control biomolecular interactions for analytical devices 15 and set the on/off state of bio-valves between catalytic nanoscale compartments. 20 We aimed to devise a binary protein complex capable of spontaneous self-assembly, on-demand disassembly in response to physical stimulus and re-assembly (Figure 1).…”