Due to excellent mechanical properties and biocompatibility, materials based on silk fibroin are increasingly included in advanced biomedical research and applications. However, their poor supporting properties for cell adhesion and proliferation represent limiting factors of the utilization. To eliminate this deficiency, we developed a series of phase-separation approaches allowing for tunable texturing of planar and 3D printed fibroin surfaces from nano to macro levels. The formation of surface structures presented is based on a combination of good and poor solvents, whereas no potentially problematic templates or additives, diminishing biocompatibility of the resulting material, are required. A critical factor in obtaining and scaling of the textures is control over the degree of transformation of fibroin secondary structures between prevalently amorphous Silk I and semicrystalline Silk II forms before and during surface treatment. Employing a set of optimized procedures, selectively or hierarchically structured fibroin surfaces can be prepared at the nano, micro, and macro level, which are characterized by long-term stability in physiological environments, allowing enhanced adhesion and proliferation of human keratinocytes as well as skin fibroblast cultivations.

• Keywords
• 3D printing, cell interaction, phase separation, secondary structure, silk fibroin, surface texture,
• MeSH
• Biocompatible Materials * chemistry   pharmacology   MeSH
• Cell Adhesion drug effects   MeSH
• Fibroblasts cytology   MeSH
• Fibroins * chemistry   pharmacology   MeSH
• Keratinocytes cytology   drug effects   MeSH
• Humans MeSH
• Surface Properties MeSH
• Cell Proliferation drug effects   MeSH
• Phase Separation MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biocompatible Materials * MeSH
• Fibroins * MeSH

This work explores application of phase separation phenomena for structuring of films made from hyaluronan. A time-sequenced dispensing of different solution mixtures was applied under rotation of hyaluronan-covered substrates to generate surface textures. This method is applicable in direct surface modification or cover layer deposition. Changes in the surface topography were characterized by atomic force microscopy, optical microscopy, and contact and non-contact profilometry. The mechanical properties of the surface-modified self-supporting films were compared using a universal testing machine. Experimental results show that diverse hyaluronan-based surface reliefs and self-supporting films with improved mechanical properties can be prepared using a newly designed multi-step phase separation process without the need for sacrificial removable templates or additives.

• Publication type
• Journal Article MeSH

The pseudo 3D hierarchical structure mimicking in vivo microenvironment was prepared by phase separation on tissue culture plastic. For surface treatment, time-sequenced dosing of the solvent mixture with various concentrations of polymer component was used. The experiments showed that hierarchically structured surfaces with macro, meso and micro pores can be prepared with multi-step phase separation processes. Changes in polystyrene surface topography were characterized by atomic force microscopy, scanning electron microscopy and contact profilometry. The cell proliferation and changes in cell morphology were tested on the prepared structured surfaces. Four types of cell lines were used for the determination of impact of the 3D architecture on the cell behavior, namely the mouse embryonic fibroblast, human lung carcinoma, primary human keratinocyte and mouse embryonic stem cells. The increase of proliferation of embryonic stem cells and mouse fibroblasts was the most remarkable. Moreover, the embryonic stem cells express different morphology when cultured on the structured surface. The acquired findings expand the current state of knowledge in the field of cell behavior on structured surfaces and bring new technological procedures leading to their preparation without the use of problematic temporary templates or additives.

• Keywords
• foams, hierarchically structured, line-specific response, phase inversion, phase separations, stem cells, surfaces,
• MeSH
• Fibroblasts * MeSH
• Microscopy, Atomic Force MeSH
• Microscopy, Electron, Scanning MeSH
• Mice MeSH
• Polymers * chemistry   MeSH
• Surface Properties MeSH
• Cell Proliferation MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Polymers * MeSH

Zein is renewable plant protein with valuable film-forming properties that can be used as a packaging material. It is known that the addition of natural cross-linkers can enhance a film's tensile properties. In this study, we aimed to prepare antimicrobial zein-based films enriched with monolaurin, eugenol, oregano, and thyme essential oil. Films were prepared using the solvent casting technique from ethanol solution. Their physicochemical properties were investigated using structural, morphological, and thermal techniques. Polar and dispersive components were analyzed using two models to evaluate the effects on the surface free energy values. The antimicrobial activity was proven using a disk diffusion method and the suppression of bacterial growth was confirmed via a growth kinetics study with the Gompertz function. The films' morphological characteristics led to systems with uniform distribution of essential oils or eugenol droplets combined with a flat-plated structure of monolaurin. A unique combination of polyphenolic eugenol and amphiphilic monoglyceride provided highly stretchable films with enhanced barrier properties and efficiency against Gram-positive and Gram-negative bacteria, yeasts, and molds. The prepared zein-based films with tunable surface properties represent an alternative to non-renewable resources with a potential application as active packaging materials.

• Keywords
• antibacterial activity, essential oils, eugenol, film, mechanical properties, monoglyceride, wettability, zein,
• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Antifungal Agents pharmacology   MeSH
• Biomechanical Phenomena drug effects   MeSH
• Calorimetry, Differential Scanning MeSH
• Escherichia coli drug effects   MeSH
• Eugenol pharmacology   MeSH
• Laurates pharmacology   MeSH
• Microscopy, Atomic Force MeSH
• Monoglycerides pharmacology   MeSH
• Food Packaging * MeSH
• Oils, Volatile pharmacology   MeSH
• Steam MeSH
• Permeability MeSH
• Surface Properties MeSH
• Wettability MeSH
• Spectroscopy, Fourier Transform Infrared MeSH
• Staphylococcus aureus drug effects   MeSH
• Zein pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Antifungal Agents MeSH
• Eugenol MeSH
• Laurates MeSH
• Monoglycerides MeSH
• monolaurin MeSH Browser
• Oils, Volatile MeSH
• Steam MeSH
• Zein MeSH

An innovative multi-step phase separation process was used to prepare tissue culture for the polystyrene-based, hierarchically structured substrates, which mimicked in vivo microenvironment and architecture. Macro- (pore area from 3000 to 18,000 µm2; roughness (Ra) 7.2 ± 0.1 µm) and meso- (pore area from 50 to 300 µm2; Ra 1.1 ± 0.1 µm) structured substrates covered with micro-pores (area around 3 µm2) were prepared and characterised. Both types of substrate were suitable for human-induced pluripotent stem cell (hiPSC) cultivation and were found to be beneficial for the induction of cardiomyogenesis in hiPSC. This was confirmed both by the number of promoted proliferated cells and the expressions of specific markers (Nkx2.5, MYH6, MYL2, and MYL7). Moreover, the substrates amplified the fluorescence signal when Ca2+ flow was monitored. This property, together with cytocompatibility, make this material especially suitable for in vitro studies of cell/material interactions within tissue-mimicking environments.

• Keywords
• biomimetic, cardiomyogenesis, fluorescence signal, human-induced pluripotent stem cells, surfaces,
• MeSH
• Biocompatible Materials chemistry   MeSH
• Cell Differentiation * MeSH
• Fluorescence * MeSH
• Induced Pluripotent Stem Cells cytology   MeSH
• Myocytes, Cardiac cytology   MeSH
• Humans MeSH
• Polystyrenes chemistry   MeSH
• Cell Proliferation MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biocompatible Materials MeSH
• Polystyrenes MeSH

The ways of producing porous-like textured surfaces with chemical etching on aluminum-alloy substrates were studied. The most appropriate etchants, their combination, temperature, and etching time period were explored. The influence of a specifically textured surface on adhesive joints' strength or superhydrophobic properties was evaluated. The samples were examined with scanning electron microscopy, profilometry, atomic force microscopy, goniometry, and tensile testing. It was found that, with the multistep etching process, the substrate can be effectively modified and textured to the same morphology, regardless of the initial surface roughness. By selecting proper etchants and their sequence one can prepare new types of highly adhesive or even superhydrophobic surfaces.

• Keywords
• adhesive bonding, alloy, aluminum, duralumin, etching, porous-like, superhydrophobic, surface texture,
• Publication type
• Journal Article MeSH