Controlled and tunable design of polymer interface for immobilization of enzymes: does curvature matter?

Abstract

Control and tuning of surface properties is indispensable for the programmed and rational design of materials. Particularly, polymeric brush-modified colloids can be used as carrier materials for enzyme immobilization. Although it is of prime importance to control the brush architecture, there is still a lack of systematic investigations concerning the impact of grafting density on the properties of the designed interface, as well as on the immobilization of biomolecules. In this work, we investigate the surface properties of polymer brushes with different grafting densities prepared using a "grafting from" approach on flat and on colloidal particle substrates by varying the density of initiator groups. In this way, we control and tune interfacial properties of the carrier material such as swelling, charge, adhesion as well as adsorption of laccase from Trametes versicolor on the grafted polyelectrolyte layer. We show that there is no direct transferability of the results received from planar to curved substrates regarding the swelling behavior in dependence on the grafting density. The maximum of swelling degree of PDMAEMA layers is achieved at 0.34 nm and at 0.1 nm grafting density for planar and curved particle substrates, respectively. The adhesion properties of the polymeric layer on both substrates are also strongly influenced by the grafting density, i.e. a decrease of the grafting density causes a transition from the adhesive to non-adhesive state. As proven by the cryo-TEM and AFM force distance measurements, an immobilization of laccase from Trametes versicolor causes a decrease of the polymer swelling and therefore leads to the changes in the surface morphology, charge and adhesion performance of final polymer-enzyme layer. Moreover, the higher effectiveness and activity of laccase were observed for the intermediate grafting densities which seem to be preferable over the maximum brush densities.

Influence of roughness and capillary size on the zeta potential values obtained by streaming potential measurements

“…Electrokinetic measurements have been performed for several decades to study surface functionalities, modifications, and interactions of solids. Some recent examples from the authors' group include the characterization of polyelectrolytes, for example, for water purification by flocculation, 2 the proof of polymer surface activation by plasma treatment and polyelectrolyte adsorption to improve adhesion, 3 a study of the influence of fiber surface properties on fiber‐matrix interactions and mechanical properties of cementitious composites, 4,5 the monitoring of surfactant adsorption on photoresist to control capillary forces in photolithography, 6 and the investigation of functional and responsive thin polyelectrolyte layers on flat surfaces 7 and nanoparticles 8 …”

“…Some recent examples from the authors' group include the characterization of polyelectrolytes, for example, for water purification by flocculation, 2 the proof of polymer surface activation by plasma treatment and polyelectrolyte adsorption to improve adhesion, 3 a study of the influence of fiber surface properties on fiber-matrix interactions and mechanical properties of cementitious composites, 4,5 the monitoring of surfactant adsorption on photoresist to control capillary forces in photolithography, 6 and the investigation of functional and responsive thin polyelectrolyte layers on flat surfaces 7 and nanoparticles. 8 Depending on size and shape of the investigated material, various techniques are available: electrophoresis NMR and particle charge detector for molecules and colloids, electrophoresis for diluted nanoparticle dispersions, electroacoustics for more concentrated dispersions, and streaming potential/streaming current measurements for fibers, powders, porous materials, and flat surfaces.…”

Shape Shifting of Cup Shaped Particles on Growing poly (2‐hydroxy ethyl methacrylate) Brushes by “Grafting From” Approach and Dissipative Particle Dynamics Simulation

“…al. . The achieved shape shifted swellable particles may function as osmotic pressure driven drug delivery vehicle which needs to be further investigated in future.…”

Funktionalisierte Kern‐Schale‐Partikel als Träger zur Enzymimmobilisierung und deren Anwendung

“…Die Partikel wurden mittels Zentrifugation aus der Reaktionslösung separiert, mehrfach in DCM und Ethanol gewaschen und schließlich bei 60 °C im Vakuum getrocknet. Im Anschluss erfolgte die Polymerisation der Polymerbürsten mittels SI‐ARGET‐ATRP . Dazu wurden die mit BrIn funktionalisierten Partikel mit Monomer, Lösemittel, CuBr 2 und Ligand (TPMA für DMAEMA, PMDTA für tBA) versetzt.…”