Ordered honeycomb structural interfaces for anticancer cells growth

Aggregation-Induced Emission-Active Biomacromolecules: Progress, Challenges, and Opportunities

Biomacromolecules featuring aggregation-induced-emission (AIE) characteristics generally present new properties and performances that are silent in the molecular state, providing endless possibilities for the evolution of biomedical applications. Tremendous achievements based on the research of AIE-active biomacromolecules have been made in synthetic exploration, material development, and practical applications. In this Perspective, we give a brief account in the development of AIE-active biomacromolecules. Remarkable progresses have been made in the exploration of AIE-active biomacromolecule preparation, structure-property relationships, and the relevant biomedical applications. The existing challenges and promising opportunities, as well as the future directions in AIE-active biomacromolecule research, are also discussed. It is expected that this Perspective can act as a trigger for the innovation of AIE-active biomacromolecule research and aggregate science.

Bio-Inspired Silica Films Combining Block Copolymers Self-Assembly and Soft Chemistry: Paving the Way toward Artificial Exosqueleton of Seawater Diatoms

This review is in line with the principles of bio-inspiration and biomimicry in order to envisage a softer and more environmentally friendly chemistry. Here, the source of inspiration is a microalga from the oceans with the ability to build an exoskeleton of silica under ambient conditions. Following this model, this review is interested in different ways of creating porous silica films with a hierarchical porosity similar to diatoms. For this purpose, polymeric/hybrid/inorganic films structured in honeycomb using the breath figure method are reported. This versatile and easy to implement method based on the principle of rapid evaporation of a solvent in a humid atmosphere is widely used in the formation of structured films with micron-sized pores. In addition to this, the self-assembly of copolymer at the nanoscale can be addressed to obtain a hierarchically structured film. Following this structuration step, the degradation of a sacrificial block is then described from the most energy-intensive to soft process, allowing an added nanoporosity to the micron porosity of the BF method. Finally, hierarchical porous silica films are described using the sol-gel process, which is known as a soft chemistry process.

Jamming and percolation of linear k-mers on honeycomb lattices

Numerical simulations and finite-size scaling analysis have been performed to study the jamming and percolation behavior of elongated objects deposited on two-dimensional honeycomb lattices. The depositing particle is modeled as a linear array of length k (so-called k-mer), maximizing the distance between first and last monomers in the chain. The separation between k-mer units is equal to the lattice constant. Hence, k sites are occupied by a k-mer when adsorbed onto the surface. The adsorption process starts with an initial configuration, where all lattice sites are empty. Then, the sites are occupied following a random sequential adsorption mechanism. The process finishes when the jamming state is reached and no more objects can be deposited due to the absence of empty site clusters of appropriate size and shape. Jamming coverage θ_{j,k} and percolation threshold θ_{c,k} were determined for a wide range of values of k (2≤k≤128). The obtained results shows that (i) θ_{j,k} is a decreasing function with increasing k, being θ_{j,k→∞}=0.6007(6) the limit value for infinitely long k-mers; and (ii) θ_{c,k} has a strong dependence on k. It decreases in the range 2≤k<48, goes through a minimum around k=48, and increases smoothly from k=48 up to the largest studied value of k=128. Finally, the precise determination of the critical exponents ν, β, and γ indicates that the model belongs to the same universality class as 2D standard percolation regardless of the value of k considered.

Recent advances on porous interfaces for biomedical applications

Porous structures on solid surfaces prepared artificially through the water droplet template method have the features of easy operation, low cost and self-removal of templates, and thus are widely applied in the fields of medicine, biomedicine, adsorption, catalysis, and separation, optical and electronic materials. Due to their tunable dimensions, abundant selection of materials, mechanical stability, high porosity, and enlarged pore surface, the formed porous interfaces show specific significance in bio-related systems. In this study, recent achievements related to applications of porous interfaces and a focus into biological and medical-related systems are summarized. The discussion involves the preparation of porous interfaces, and porous interface-induced cell behaviors including culture, growth, proliferation, adhesion, and differentiation of cells. The inhibitory effect of bacteria and separated features of microorganisms supported by porous interfaces, the immobilization of biomolecules related to proteins, DNA and enzymes, and the controllable drug delivery are also discussed. The summary of recent advances pointed out in the study, are suggestive of insights for motivating unique potential applications including their extension to porous interfaces in biomedical materials.

Engineered Three-Dimensional Scaffolds Modulating Fate of Breast Cancer Cells Using Stiffness and Morphology Related Cell Adhesion

Goal: Artificially engineering the tumor microenvironment in vitro as a vital tool for understanding the mechanism of tumor progression. In this study, we developed three-dimensional cell scaffold systems with different topographical features and mechanical properties but similar surface chemistry. The cell behavior was modulated by the topography and mechanical properties of the scaffold. Methods: Adenocarcinoma (MCF7), triple-negative (MDA-MB-231) and premalignant (MCF10AneoT) breast cancer cells were seeded on the scaffold systems. The cell viability, cell-cell interaction and cell-matrix interactions were analyzed. The preferential growth and alignment of specific population of cells were demonstrated. Results: Among the different scaffolds, triple-negative breast cancer cells preferred honeycomb scaffolds while adenocarcinoma cells favored mesh scaffolds and premalignant cells preferred the aligned scaffolds. Conclusions: The 3D model system developed here can be used to support growth of only specific cell populations or for the growth of tumors. This model can be used for understanding the topographical and mechanical features affecting tumorigenesis, cancer cell growth and migration behavior of malignant and metastatic cancer cells.

Direct formation of hydrophilic honeycomb film by self-assembly in breath figure templating of hydrophobic polylacticacid/ionic surfactant complexes

Honeycomb-patterned porous films with good surface wettability have great potential applications in various areas. However, hydrophilic honeycomb films are difficult to obtain using the direct self-assembly of pure (co)polymers. Thus, additional and special treatments are required to improve film wettability, which makes the procedure complicated and difficult to access. In this study, a facile way to prepare hydrophilic honeycomb-structured porous films is proposed that uses the direct self-assembly of complexes of biocompatible hydrophobic poly(l-lactic acid) and dodecyltrimethylammonium chloride by breath figure templating. The addition of ionic surfactant not only improves film quality but also confers good wettability. The obtained hydrophilic pore arrays were found to effectively promote cell attachment. Such a hydrophilic honeycomb-patterned porous film could find potential applications where pore wetting is required, including tissue engineering, lithography, and nanoparticle embedding.

Hierarchical Polymer Structures Using Templates and the Modified Breath Figure Method

Hierarchical structures are commonly observed in nature and possess unique properties. The fabrication of hierarchical structures with well-controlled sizes in different length scales, however, is still a great challenge. To further understand the morphologies and properties of the hierarchical structures, here we present a novel strategy to prepare hierarchical polymer structures by combining the modified breath figure method and the template method. Poly(methyl methacrylate) (PMMA) honeycomb films with regular micropores are first prepared using the modified breath figure method by dipping PMMA films into mixtures of chloroform and methanol. The polymer chains on the honeycomb films are then annealed and wetted into the nanopores of anodic aluminum oxide templates via capillary forces, resulting in the formation of hierarchical polymer structures. The morphologies of the polymer structures, which can be controlled by the molecular weights of the polymers and the concentrations of the polymer solutions, are characterized by scanning electron microscopy. The surface wettabilities of the polymer structures are also examined by water contact angle measurements, and the hierarchical structures are observed to be more hydrophobic than the flat films and honeycomb films. This work not only provides a feasible approach to fabricate hierarchical polymer structures with controlled sizes but also gives a better understanding of the relationship between surface morphologies and properties.

Designing 3D Biological Surfaces via the Breath-Figure Method

The fabrication of biointerfaces that mimic cellular physiological environments is critical to understanding cell behaviors in vitro and for the design of tissue engineering. Breath figure is a self-assemble method that uses water droplets condensed from moisture as template and ends up with a highly ordered hexagonal pore array; this approach is used to fabricate various biological substrates. This progress report provides an overview of strategies to achieve topographical modifications and chemical-patterned arrays, such as modulation of the pore size, shape and selective decoration of the honeycomb holes. Using recent results in the biological fields, potential future applications and developments of honeycomb structures are commented upon.

Honeycomb-patterned hybrid films of surfactant-encapsulated polyoxometalates by a breath figure method and its electrocatalysis for BrO3−

Surfactant-encapsulated POMs can self-assemble into ordered porous honeycomb films under a moist atmosphere. We successfully fabricated (DODA)₁₀{Cu₄(PW₉)₂} honeycomb films by using a one-step method.

Fabrication of the graphene honeycomb structure as a scaffold for the study of cell growth

The good biocompatibility of the graphene honeycomb structure was evaluated by the proliferation of HeLa and MCF-7 cell lines.

Porous membranes based on poly(ether imide)-graft-poly(vinyl acetate) as a scaffold for cell growth

A series of poly(ether imide)-graft-poly(vinyl acetate) copolymers with different molecular weights were synthesized successfully and characterized using Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimeter, thermogravimetric analysis, and X-ray photoelectron spectroscopy analyses. These copolymers were used to fabricate honeycomb-structured porous films using the breath figure templating technique. The surface topology and composition of the highly ordered pattern film were further characterized using a scanning electron microscopy. The results indicated that the poly(ether imide)-graft-poly(vinyl acetate) graft molecular weight ratio influenced the breath figure film surface topology. A model was proposed to elucidate the stabilization process of the poly(ether imide)-graft-poly(vinyl acetate)-aggregated architecture on the water droplet–based templates. In addition, cell viability has been investigated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test, and the cell morphology on the honeycomb-structured poly(ether imide)-graft-poly(vinyl acetate) porous film has been evaluated using a fluorescence microscope. This porous film is shown to be suitable as a matrix for cell growth.

Wettability with Aggregation-Induced Emission Luminogens

Aggregation-induced emission luminogens (AIEgens) have become an emerging field since the concept of AIE was proposed in 2001. Recently, AIEgens have attracted considerable attention due to their abnormal non-emissive fluorescent behavior in solution but strongly emissive behavior in the aggregate state. By utilizing the inherent hydrophobicity, AIEgens can be used to monitor the crystal formation and dewetting behavior in the self-assembly process. More importantly, some stimuli-responsive AIE-active surfaces have been successfully fabricated. In this perspective review, we outline the advances of surface wettability of AIEgens and its applications.

Multiphase Media Antiadhesive Coatings: Hierarchical Self-Assembled Porous Materials Generated Using Breath Figure Patterns

The cleaning of interface pollutants typically consumes a large amount of energy. Therefore, the development of multiphase media antiadhesive materials is urgently required to meet the demand of energy savings and environmental protection. In this study, the antiadhesive properties toward several liquid droplets and bubbles in multiple media are demonstrated on a porous Fe₂O₃ coating, which is prepared via a facile spin-coating-assisted breath figure approach and a phase separation strategy. The prominent antiadhesive characteristic of these porous surfaces lies in their high-surface-energy hierarchical micro/nanoscale structure, which easily entraps one medium (oil or water) in the pore and repels other unmixable liquids and air bubbles. In addition, we successfully demonstrate an antifouling application of the coating, which shows excellent antiadhesive and super-antiwetting characteristics under multiple liquids. Our work extends relevant antiadhesion research from a single medium to multiple media and promises to broaden the applications of antiadhesive materials in sophisticated activities performed under complicated liquid environments, such as marine antifouling or pipeline transportation.

Strengthening of polymer ordered porous materials based on a layered nanocomposite internal structure

Ordered porous polymeric films attract more and more attention because they have many advantages and broad application prospects in many fields. But because of their large flexibility and poor mechanical properties, some of the scope for application is greatly limited. Inspired by the ordered pore structure of the honeycomb and the layered structure of natural nacre, we prepared an ordered porous polymer film with a layered structure in the pore wall by the solvent-evaporation-restriction assisted hard template method. Compared with other samples, this kind of film with the layered structure showed both excellent mechanical properties and good stability. This kind of film with high mechanical strength, is considered to have wide applications in the areas of separation, biomedicine, precision instruments, aerospace, environmental protection and so on.

Honeycomb porous films of pentablock copolymer on liquid substrates via breath figure method and their hydrophobic properties with static and dynamic behaviour

The peeled film obtained on the isopropanol substrate through breath figure method exhibits the best hydrophobic properties, and the water droplet impact behavior shows an obvious rebound tendency and a weak maximum spreading diameter.

Biomimetic honeycomb-patterned surface as the tunable cell adhesion scaffold

PS honeycomb structured surfaces were modified into both cell-philic and cell-phobic by dip-coating and casting polySBMA, respectively, which was inspired by two typically adhesive behaviours of fish skin and Parthenocissus tricuspidata.

Synthesis of core cross-linked star polystyrene with functional end groups and self-assemblies templated by breath figures

We report the synthesis of core cross-linked star (CCS) polymers with functional end groups for self-assembled films, which show mono-layer and multi-layer transition, depending on arm numbers, arm length, and end groups.