Cellular interactions on hierarchical poly(ε-caprolactone) nanowire micropatterns

Poly(ε-Caprolactone) Substrates with Micro/Nanohierarchical Patterned Structures for Cell Culture

A simple, efficient and controllable one-step template method is proposed to fabricate poly(ε-caprolactone) substrates with micro/nanohierarchical patterned structures. Two kinds of geometric patterns with and without nanowires, i.e., hexagonal and strip with controllable island size and spacing are designed and fabricated. Furthermore, the influence of geometric patterns, island size, island spacing, and patterned nanowires (pNW) on the growth behavior of MG-63 cells is studied in terms of cell density, distribution, proliferation, morphogenesis, and cellular alignment. It is found that MG-63 cells prefer to adhere and grow on the substrate with smaller island size or spacing. Moreover, unlike the hexagonal structure, the strip structure can guide cellular alignment on its surface. In addition, the microisland structures and the pNW play different roles in promoting cell proliferation, distribution, and morphogenesis. It is concluded that the growth behavior of MG-63 cells can be well controlled by precisely adjusting the micro/nanostructure of the substrate surface. A simple and effective method is provided here for the regulation of cell growth behavior.

Utilizing Cell Culture Assisted Anodization to Fabricate Aluminium Oxide with a Gradient Microstep and Nanopore Structure

Anodic aluminum oxide (AAO) with a gradient microstep and nanopore structure (GMNP) is fabricated by inversely using cell culture to control the reaction areas in the electrochemical anodization, which shows a larger porosity than that of typical planar AAO. The figure of the microstep is influenced by the cell dehydration temperature which controls the cell shrinkage degree. A GMNP AAO with a diameter of 2.5 cm is achieved. Polymer with a gradient microstep and nanonipple structure is fabricated using the GMNP AAO as the template, which denotes that GMNP AAO could become a broad platform for the structural preparation of various materials with advanced functions.

A facile method for high-throughput screening of drug-eluting coatings in droplet microarrays based on ultrasonic spray deposition

Coating modification such as drug-eluting coating is one of the most important approaches for the functionalization of biomedical devices. However, the throughputs are limited in conventional coating methods and the concept of miniaturization is rarely fulfilled. A droplet microarray (DMA), as a unique high-throughput platform, can avoid cross-contamination and reduce the consumption of materials which is inherently suitable for coating research yet is difficult to apply with coating materials via traditional methods. Here, we bring up a facile method based on ultrasonic spray deposition to integrate coating materials into a DMA. Several common polymer materials were selected to fabricate a DMA, and the obtained DMA showed the ability to anchor water droplets and form specific patterns. Coating arrays with a typical sandwich structure were also prepared for the high-throughput screening of drug-eluting coatings to demonstrate the potential of the platform in coating research. This developed method is efficient and compatible and enriches the choices of materials that can be applied in DMAs.

The phase transition behavior of poly(butylene adipate) in the nanoporous anodic alumina oxide

PBA nanotubes with different diameters have been prepared.

Structural evolution of low-molecular-weight poly(ethylene oxide)-block-polystyrene diblock copolymer thin film

The structural evolution of low-molecular-weight poly(ethylene oxide)-block-polystyrene (PEO-b-PS) diblock copolymer thin film with various initial film thicknesses on silicon substrate under thermal annealing was investigated by atomic force microscopy, optical microscopy, and contact angle measurement. At film thickness below half of the interlamellar spacing of the diblock copolymer (6.2 nm), the entire silicon is covered by a polymer brush with PEO blocks anchored on the Si substrate due to the substrate-induced effect. When the film is thicker than 6.2 nm, a dense polymer brush which is equal to half of an interlamellar layer was formed on the silicon, while the excess material dewet this layer to form droplets. The droplet surface was rich with PS block and the PEO block crystallized inside the bigger droplet to form spherulite.

Optical regulation of protein adsorption and cell adhesion by photoresponsive GaN nanowires

Interfacing nanowires with living cells is attracting more and more interest due to the potential applications, such as cell culture engineering and drug delivery. We report on the feasibility of using photoresponsive semiconductor gallium nitride (GaN) nanowires (NWs) for regulating the behaviors of biomolecules and cells at the nano/biointerface. The GaN NWs have been fabricated by a facile chemical vapor deposition method. The superhydrophobicity to superhydrophilicity transition of the NWs is achieved by UV illumination. Bovine serum albumin adsorption could be modulated by photoresponsive GaN NWs. Tunable cell detachment and adhesion are also observed. The mechanism of the NW surface responsible for modulating both of protein adsorption and cell adhesion is discussed. These observations of the modulation effects on protein adsorption and cell adhesion by GaN NWs could provide a novel approach toward the regulation of the behaviors of biomolecules and cells at the nano/biointerface, which may be of considerable importance in the development of high-performance semiconductor nanowire-based biomedical devices for cell culture engineering, bioseparation, and diagnostics.

Tailoring the nanostructured surfaces of hydroxyapatite bioceramics to promote protein adsorption, osteoblast growth, and osteogenic differentiation

To promote and understand the biological responses of the implant via nanostructured surface design is essential for the development of bioactive bone implants. However, the control of the surface topography of the bioceramics in nanoscale is a big challenge because of their brittle property. Herein, the hydroxyapatite (HAp) bioceramics with distinct nanostructured topographies were fabricated via hydrothermal treatment using α-tricalcium phosphate ceramic as hard-template under different reaction conditions. HAp bioceramics with nanosheet, nanorod and micro-nanohybrid structured surface in macroscopical size were obtained by controlling the composition of the reaction media. Comparing with the traditional sample with flat and dense surface, the fabricated HAp bioceramics with hierarchical 3D micro-nanotextured surfaces possessed higher specific surface area, which selectively enhanced adsorption of specific proteins including Fn and Vn in plasma, and stimulated osteoblast adhesion, growth, and osoteogenic differentiation. In particular, the biomimetic features of the hierarchical micro-nanohybrid surface resulted in the best ability for simultaneous enhancement of protein adsorption, osteoblast proliferation, and differentiation. The results suggest that the hierarchical micro-nanohybrid topography might be one of the critical factors to be considered in the design of functional bone grafts.