Switching the Stiffness of Polyelectrolyte Assembly by Light to Control Behavior of Supported Cells

Abstract

Polyelectrolyte block copolymer micelles assembled thin film is switched in response to local photocatalytic reactions on titanium dioxide, resulting in a layer of variable height, stiffness in response to visible light irradiation. Preosteoblasts migrate toward stiffer side of the substrates.

In Situ Characterization of Interfaces Relevant for Efficient Photoinduced Reactions

“…It is a challenging task to control spatiotemporal system gradients. Ulasevich et al proved that it is promising to use inorganic semiconductors to initiate a spatial‐temporal gradient of pH on their surfaces . An effective generation of proton gradients on TiO 2 surfaces under irradiation has been introduced to control the bioactivity of the system for specific bioapplications of guiding cell migration on the surface for coculturing biochips, and for protein recognition/modulation elements …”

“…The question concerns synergetic network regulation and spatiotemporal surface bioactivity to attract, deactivate, and affect their metabolism and desorb bacteria . Subquestions are then related to (i) the mechanisms behind the effect of ROS on the bacteria; (ii) the ion gradient to support growth of selective bacteria types located on certain areas; and (iii) the effects of the surface‐modified films as the photocontrollable bioactuators such as conformational transitions in the polymeric film …”

How Can One Controllably Use of Natural ΔpH in Polyelectrolyte Multilayers?

“…Strong and weak polyelectrolyte assemblies, including biopolymers, pH sensitive micelles were studied to regulate the diffusion of protons to have morphological changes in PEs assemblies. We have man aged [100] to develop multilayers, which can be activated with light due to a pH change on the titania surface. The system is shown in Figure 8, irradiation in the experiment was done from back contact and adsorbed by a titania layer.…”

Light‐Induced Water Splitting Causes High‐Amplitude Oscillation of pH‐Sensitive Layer‐by‐Layer Assemblies on TiO2

“…Quantitative analysis for the promising pH sensitive assembly of architecture TiO 2 /BCM/PAA/BCM/PAA reveals am odulation of the thickness by afactor of 4and achange of elastic modulus by more than an order of magnitude.T he light-pH coupled actuation of soft matter is efficient for the formation of drug delivery capsules, [7,20] self-repairing coatings,a nd to guide cells via local elasticity changes ( Figure S6), [21] microfluidics,lab-on-chip,sensors,nano-lithography. TheLbL assembly provides an efficient structure for the fast trapping of photogenerated H + ions.T he kinetics of light-pH coupled actuation and modulation show that such LbL surfaces are fast switchable and slowly relaxing.…”

“…We thus demonstrate that the photogenerated charges in asolid can be used to change the properties of adjacent soft matter. Quantitative analysis for the promising pH sensitive assembly of architecture TiO 2 /BCM/PAA/BCM/PAA reveals am odulation of the thickness by afactor of 4and achange of elastic modulus by more than an order of magnitude.T he light-pH coupled actuation of soft matter is efficient for the formation of drug delivery capsules, [7,20] self-repairing coatings,a nd to guide cells via local elasticity changes ( Figure S6), [21] microfluidics,lab-on-chip,sensors,nano-lithography. [22] In conclusion, we demonstrate here as imple process: irradiation of as emiconductor surface causes ac harge separation, leading to water splitting and to ap Hc hange.…”