The development of novel bioinspired surfaces with hierarchical micro- and nanoscale topographic structures for efficient capture and release of circulating tumor cells (CTCs) is reported. The capture of CTCs, facilitated by surface-immobilized epithelial cell adhesion molecule antibodies (anti-EpCAM), was shown to be significantly enhanced in novel three-dimensional hierarchically structured surfaces that were fabricated by replicating the natural micro- and nanostructures of rose petals. Under static conditions, these hierarchical capture substrates exhibited up to 6 times higher cell capture ability at concentrations of 100 cells mL in contrast to flat anti-EpCAM-functionalized polydimethylsiloxane (PDMS) surfaces. As indicated by scanning electron microscopy (SEM) and immunofluorescent images, this enhancement can be in large part attributed to the topographical interaction between nanoscale cell surface components and nanostructures on the substrate. Similarly, the increased surface area affords a higher nominal coverage of anti-EpCAM, which increases the number of available binding sites for cell capture. By treating the substrates with the biocompatible reductant glutathione (GSH), up to 85% of the captured cells were released, which displayed over 98% cell viability after culturing on tissue culture polystyrene (TCP) for 24 h. Therefore, these bioinspired hierarchically structured and functionalized substrates can be successfully applied to capture CTCs, as well as release CTCs for subsequent analysis. These findings provide new prospects for designing cell-material interfaces for advanced cell-based biomedical studies in the future.

Battery-like supercapacitors feature high power and energy densities as well as long-term capacitance retention. The utilized capacitor electrodes are thus better to have large surface areas, high conductivity, high stability, and importantly be of binder free. Herein, vertically 3-/4-), respectively For assembled two-electrode symmetrical supercapacitor devices, the capacitances of EDLC and PC devices reach 30 and 48 mF cm -2 at 10 mV s -1 , respectively.They remain constant even after 10 000 cycles.

This study reports on the dependence of the temperature-induced changes in the properties of thin thermoresponsive poly(diethylene glycol) methyl ether methacrylate (PDEGMA) layers of end-tethered chains on polymer thickness and grafting density. PDEGMA layers with a dry ellipsometric thickness of 5-40 nm were synthesized by surface-initiated atom transfer radical polymerization on gold. To assess the temperature-induced changes, the adsorption of bovine serum albumin (BSA) was investigated systematically as a function of film thickness, temperature, and grafting density by surface plasmon resonance (SPR), complemented by wettability and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. BSA adsorption on PDEGMA brushes is shown to differ significantly above and below an apparent transition temperature. This surface transition temperature was found to depend linearly on the PDEGMA thickness and changed from 35 °C at 5 nm thickness to 48 °C at 23 nm. Similarly, a change of the grafting density enables the adjustment of this transition temperature presumably via a transition from the mushroom to the brush regime. Finally, BSA that adsorbed irreversibly on polymer brushes at temperatures above the transition temperature can be desorbed by reducing the temperature to 25 °C, underlining the reversibly switchable properties of PDEGMA brushes in response to temperature changes.

Poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) brushes, which are known to suppress protein adsorption and prevent cell attachment, are reported here to possess interesting and tunable thermoresponsive behavior, if the brush thickness is reduced or the grafting density is altered. PDEGMA brushes with a dry ellipsometric thickness of 5 ± 1 nm can be switched from cell adherent behavior at 37 °C to cell nonadherent at 25 °C. This behavior coincides with the temperature-dependent irreversible adsorption of fibronectin from phosphate saline buffer and proteins present in the cell culture medium, as unveiled by surface plasmon resonance measurements. Unlike for tissue culture polystyrene reference surfaces, swelling of the PDEGMA chains below the lower critical solution temperature results in the absence of paxillin and actin containing cellular filaments responsible for cell attachment. These tunable properties of very thin homopolymer PDEGMA brushes render this system interesting as an alternative thermoresponsive layer for continuous cell culture or enzyme-free cell culture systems.

To tailor cell–surface interactions, precise and controlled attachment of cell‐adhesive motifs is required, while any background non‐specific cell and protein adhesion has to be blocked effectively. Herein, a versatile and highly reproducible antifouling surface modification based on “clickable” groups and hierarchically structured diblock copolymer brushes for the controlled attachment of cells is reported. The polymer brush architecture combines an antifouling bottom block of poly(2‐hydroxyethyl methacrylate) poly(HEMA) and an ultrathin azide‐bearing top block, which can participate in well‐established “click” reactions including the highly selective copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) reaction under mild conditions. This straightforward approach allows the rapid conjugation of a cell‐adhesive, alkyne‐bearing cyclic RGD peptide motif, enabling subsequent specific attachment of NIH 3T3 fibroblasts, their extensive proliferation and confluent cell sheet formation after 48 h of incubation. The generally applicable strategy presented in this report can be employed for surface functionalization with diverse alkyne‐bearing biological moieties via CuAAC or copper‐free alkyne‐azide cycloaddition protocols, making it a versatile functionalization approach and a promising tool for tissue engineering, biomaterial implant design, and other applications that require surfaces supporting highly specific cell attachment.