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A simple and efficient method for the synthesis of biodegradable, highly branched polycaprolactone (PCL) is presented. The solvent-free (bulk) reaction was carried out via ring opening polymerization (ROP), catalyzed by tin octanoate Sn(Oct)2, and it employed hyperbranched polyamide (HPPA) as a macro-initiator. The core–shell structure of the obtained products (PCL-HPPA), with the hyperbranched HPPA core and linear PCL chains as shell, was in the focus of the product characterization. 1H nuclear magnetic resonance (1H NMR) and elemental analysis confirmed the covalent incorporation of the HPPA in the products, as well as a high degree of grafting conversion of its amino functional groups. Confocal Raman Micro spectroscopy, and especially Time-of-Flight Secondary Ion Mass Spectrometry, further supported the existence of a core–shell structure in the products. Direct observation of macromolecules by means of cryogenic transmission electron microscopy, as well as gel permeation chromatography (GPC), suggested the existence of a minor 'aggregated' product fraction with multiple HPPA cores, which was attributed to transesterification reactions. Differential scanning calorimetry, as well as X-ray diffraction, demonstrated that the PCL-HPPA polymers displayed a similar degree of crystallinity to linear neat PCL, but that the branched products possessed smaller and less regular crystallites. [ABSTRACT FROM AUTHOR]

The unique features of poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA), such as its sensitivity to external stimuli like pH and the presence of tertiary amine groups that can be easily quaternized to introduce antibacterial properties, make it a promising platform for biomedical applications. In this contribution, a facile, cost‐effective, and ecological procedure for controlled grafting of PDMAEMA brushes from a glass surface, both in mL and µL scale, is developed. This concept involves utilizing an aqueous solution of sunflower honey as a source of reducing sugars to accelerate surface‐initiated activators regenerated by electron transfer atom transfer radical polymerization. The PDMAEMA chains covalently grafted to the glass surface are then quaternized to form an antibacterial film. The thickness of the polymeric brush layer is determined by atomic force microscopy, while the chemical composition is analyzed by time of flight secondary ion mass spectrometry. Water contact angle measurements demonstrate the pH‐sensitivity of PDMAEMA pointing out the potential application of the prepared material as smart surfaces. Furthermore, the antibacterial tests against Gram‐positive and Gram‐negative bacteria strains are performed. The protein adsorption is used to evaluate the biocompatibility of the prepared surfaces. The resulting glass materials can serve as multifunctional surfaces for various purposes. [ABSTRACT FROM AUTHOR]

Fluorinated polymers have unique wettability and protein adsorption properties. The site-specific alteration of these properties could expand their application to different research areas. In this work, a fluorinated homopolymer and two of its copolymers with 4-vinylbenzyl glycidyl ether (VBGE) are synthesized by free radical polymerization. The produced polymers are then used to develop resist formulations by the addition of a photoacid generator. Films of these formulations are exposed to ultraviolet radiation through a binary mask and heated to create the pattern. It is found that the water contact angle values of the exposed films areas are reduced compared to those of the unexposed ones, with the exception of pentafluorophenyl methacrylate (PFMA) homopolymer film. This is attributed to the reaction of the epoxy groups creating x-links and producing hydroxyl groups and the cleavage of the pentafluorophenyl group from the ester group leading to carboxylic acid groups. Both modifications on the exposed areas are verified by FTIR spectroscopy and ToF-SIMS analysis. In addition, the biomolecules adsorption ability of the exposed area is increasing 10–15 times compared to the unexposed one for the PFMA homopolymer and the PFMA/VBGE 1:1 copolymer. Thus, the proposed polymers and patterning procedure could find application to spatially directed immobilization of biomolecules and/or cells onto a surface for both biosensing and tissue engineering purposes. [ABSTRACT FROM AUTHOR]

The fibrotic fibroblasts derived from idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP) are surrounded by specific environments, characterized by increased stiffness, aberrant extracellular matrix (ECM) composition, and altered lung architecture. The presented research was aimed at investigating the effect of biological, physical, and topographical modification of the substrate on the properties of IPF- and NSIP-derived fibroblasts, and searching for the parameters enabling their identification. Soft and stiff polydimethylsiloxane (PDMS) was chosen for the basic substrates, the properties of which were subsequently tuned. To obtain the biological modification of the substrates, they were covered with ECM proteins, laminin, fibronectin, and collagen. The substrates that mimicked the 3D structure of the lungs were prepared using two approaches, resulting in porous structures that resemble natural lung architecture and honeycomb patterns, typical of IPF tissue. The growth of cells on soft and stiff PDMS covered with proteins, traced using fluorescence microscopy, confirmed an altered behavior of healthy and IPF- and NSIP-derived fibroblasts in response to the modified substrate properties, enabling their identification. In turn, differences in the mechanical properties of healthy and fibrotic fibroblasts, determined using atomic force microscopy working in force spectroscopy mode, as well as their growth on 3D-patterned substrates were not sufficient to discriminate between cell lines. [ABSTRACT FROM AUTHOR]

The effect of temperature and buffer solutions with different pH (often used in biomedical applications) on the behavior of POEGMA brush coatings, synthesized without incorporated functional groups, was for the first time studied in details using water contact angle (CA) measurements and atomic force microscopy (AFM). Thermal response of grafted brush-coatings based on poly(oligo(ethylene glycol) methacrylate)s (POEGMA)s is driven by lower critical solution temperature (LCST) phenomenon. Obtained CA and AFM results suggest strong impact of the buffer solutions on the values of LCST transition and contact angle ranges, as well as on coatings morphology. In turn, ellipsometry data reflect penetration of salt ions from buffer solutions into brush-coatings. In contrast to "typical" behavior of POEGMA coatings in water, different mechanisms available below LCST in the buffer solutions destroy hydrated layers surrounding POEGMA macromolecules leading to their collapse. [ABSTRACT FROM AUTHOR]

Control over orientation and conformation of surface-immobilized proteins, determining their biological activity, plays a critical role in biointerface engineering. Specific protein state can be achieved with adjusted surface preparation and immobilization conditions through different types of protein-surface and protein-protein interactions, as outlined in this work. Time-of-flight secondary ion mass spectroscopy, combining surface sensitivity with excellent chemical specificity enhanced by multivariate data analysis, is the most suited surface analysis method to provide information about protein state. This work highlights recent applications of the multivariate principal component analysis of TOF-SIMS spectra to trace orientation and conformation changes of various proteins (antibody, bovine serum albumin, and streptavidin) immobilized by adsorption, specific binding, and covalent attachment on different surfaces, including self-assembled monolayers on silicon, solution-deposited polythiophenes, and thermo-responsive polymer brushes. Multivariate TOF-SIMS results correlate well with AFM data and binding assays for antibody-antigen and streptavidin-biotin recognition. Additionally, several novel extensions of the multivariate TOF-SIMS method are discussed. Graphical abstract [ABSTRACT FROM AUTHOR]

In the present work, three types of grafted brush coatings [P4VP, POEGMA246, and P(4VP-co-POEGMA246)] were successfully fabricated using graft polymerization of monomers "from the surface." The composition, thickness, and morphology of the grafted brush coatings were analyzed by TOF-SIMS, ellipsometry, and AFM, respectively. The chemical nature of the polymer surface plays a crucial role in the growth and development of the cow granulosa cells and, therefore, also oocyte-cumulus complexes. In comparison with other coatings, the P(4VP-co-POEGMA246) copolymer coating enables the formation of dispersed and small but numerous cell conglomerates and high cumulus expansion in oocyte-cumulus complexes with highly homogeneous cumulus layers surrounding the oocytes. Moreover, the cellular oxygen uptake for this coating in the presence of NaF (inhibitor glycolysis) was stimulated. This new (4VP-co-POEGMA246) copolymer nanostructured coating is a promising material for granulosa cell and oocyte-cumulus complex cultivation and possibly will have great potential for applications in veterinary and reproductive medicine. [ABSTRACT FROM AUTHOR]

In this work, we present plasma etching alone as a directed assembly method to both create the nanodot pattern on an etched polymeric (PMMA) film and transfer it to a silicon substrate for the fabrication of silicon nanopillars or cone-like nanostructuring. By using a shield to control sputtering from inside the plasma reactor, the size and shape of the resulting nanodots can be better controlled by varying plasma parameters as the bias power. The effect of the shield on inhibitor deposition on the etched surfaces was investigated by time-of-flight secondary ion mass spectroscopy (ToF-SIMS) measurements. The fabrication of quasi-ordered PMMA nanodots of a diameter of 25 nm and period of 54 nm is demonstrated. Pattern transfer to the silicon substrate using the same plasma reactor was performed in two ways: (a) a mixed fluorine-fluorocarbon-oxygen nanoscale etch plasma process was employed to fabricate silicon nanopillars with a diameter of 25 nm and an aspect ratio of 5.6, which show the same periodicity as the nanodot pattern, and (b) high etch rate cryogenic plasma process was used for pattern transfer. The result is the nanostructuring of Si by high aspect ratio nanotip or nanocone-like features that show excellent antireflective properties. [ABSTRACT FROM AUTHOR]

Abstract: The origin and formation of the dipole moment at the interface of metal electrode and thin organic film is crucial for the fabrication of high‐performance organic electronic devices. In this work, model polymer multilayer systems are studied in which interfaces are modified heterogeneously with thiol‐based self‐assembled monolayers (SAM). Due to the presence of polar terminal group (‐COOH) in SAM and polar pendant groups (‐COOH, ‐C(O)OCH3) within studied polymers, it is pointed out that the resultant interface energetics differ from the expected ones as one would expect from the chemical character of the self‐assembled molecules used to tune junction properties. This is discussed in terms of inter‐association and depolarization effects between polymer and thiol modified substrate. The presented model systems may serve as an interaction reference for SAMs and semiconducting polymers containing similar moieties, utilized for the fabrication of organic electronic devices. [ABSTRACT FROM AUTHOR]

Poly(n-butyl methacrylate) (PBMA) grafted polymer brushes attached to glass were fabricated in a three-step process involving surface initiated atom transfer radical polymerization. The surface properties of the coatings after subsequent fabrication steps were confirmed using ToF-SIMS and ellipsometry. Measurements of water contact angle and AFM revealed temperature-induced changes in the hydrophobicity and morphology of the coating. The glass transition temperatures (Tg) of the PBMA coatings with different thicknesses were determined from the AFM measurements. For the PBMA grafted brush coatings with thicknesses less than 62 nm, Tg increases sharply with increasing thickness. The PBMA grafted coatings of thickness equal to 86 nm and 43 nm as well as control glass substrates were used as substrates for culturing a urinary bladder cancer HTB-5 cell line. After 144 h of culturing, a well-developed monocellular layer may be observed on the PBMA coating of thickness equal to 86 nm. In turn, the cells incubated on thinner (43 nm) PBMA coatings as well as on a control glass sample only start to form a confluent layer. [ABSTRACT FROM AUTHOR]

Tuning the transition between stable hydrophilicity and high etching-rate and simultaneous hydrophilization of polymethylmethacrylate (PMMA) films was achieved in an open-air environment simply by adjusting the O2 content in He gas injection through the showerhead-type electrode of a novel atmospheric pressure dielectric barrier discharge source. A comparative study was performed for He and He-O2 plasma treatment of PMMA. Electrical and optical measurements indicated severe alteration of plasma characteristics when O2 is added in gas feed. The enhancement of oxygen emission band intensities indicates an enhanced concentration of atomic oxygen, resulting in very high PMMA etching rates of ~320 nm/min, ~four times higher compared to pure He. In contrast, the He plasma showed higher nitrogen emission band intensities, translated into a higher nitrogen content on the PMMA surface according to x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. This enhanced nitrogen content due to the partial substitution of ester groups of the PMMA side chain with amide groups was responsible for the more efficient hydrophilization of the PMMA surface. A water contact angle as low as ~28#176; was achieved, stabilizing at ~40° after 10 days and remained constant at least for 45 days, significantly lower than that for the untreated PMMA (~69°) [ABSTRACT FROM AUTHOR]

Among the various biomarkers that are used to diagnose or monitor disease, extracellular vesicles (EVs) represent one of the most promising targets in the development of new therapeutic strategies and the application of new diagnostic methods. The detection of circulating platelet-derived microvesicles (PMVs) is a considerable challenge for laboratory diagnostics, especially in the preliminary phase of a disease. In this study, we present a multistep approach to immobilizing and detecting PMVs in biological samples (microvesicles generated from activated platelets and human platelet-poor plasma) on functionalized silicon substrate. We describe the application of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and spectroscopic ellipsometry methods to the detection of immobilized PMVs in the context of a novel imaging flow cytometry (ISX) technique and atomic force microscopy (AFM). This novel approach allowed us to confirm the presence of the abundant microvesicle phospholipids phosphatidylserine (PS) and phosphatidylethanolamine (PE) on a surface with immobilized PMVs. Phosphatidylcholine groups (CHN; CHPNO ) were also detected. Moreover, we were able to show that ellipsometry permitted the immobilization of PMVs on a functionalized surface to be evaluated. The sensitivity of the ISX technique depends on the size and refractive index of the analyzed microvesicles. [ABSTRACT FROM AUTHOR]

Three multi-step multi-molecular approaches using the biotin–streptavidin system to contact-print DNA arrays on SiO2 surfaces modified with (3-glycidoxypropyl)trimethoxysilane are examined after each deposition/reaction step by atomic force microscopy, X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry. Surface modification involves the spotting of preformed conjugates of biotinylated oligonucleotides with streptavidin onto surfaces coated with biotinylated bovine serum albumin b-BSA (approach I) or the spotting of biotinylated oligonucleotides onto a streptavidin coating, the latter prepared through a reaction with immobilized b-BSA (approach II) or direct adsorption (approach III). AFM micrographs, quantified by autocorrelation and height histogram parameters (e.g. roughness), reveal uniform coverage after each modification step with distinct nanostructures after the reaction of biotinylated BSA with streptavidin or of a streptavidin conjugate with biotinylated oligonucleotides. XPS relates the immobilization of biomolecules with covalent binding to the epoxy-silanized surface. Protein coverage, estimated from photoelectron attenuation, shows that regarding streptavidin the highest and the lowest immobilization efficiency is achieved by following approaches I and III, respectively, as confirmed by TOF-SIMS microanalysis. The size of the DNA spot reflects the contact radius of the printed droplet and increases with protein coverage (and roughness) prior to the spotting, as epoxy-silanized surfaces are hardly hydrophilic. Representative TOF-SIMS images show sub-millimeter spots: uniform for approach I, doughnut-like (with a small non-zero minimum) for approach II, both with coffee-rings or peak-shaped for approach III. Spot features, originating from pinned contact lines and DNA surface binding and revealed by complementary molecular distributions (all material, DNA, streptavidin, BSA, epoxy, SiO2), indicate two modes of droplet evaporation depending on the details of each applied approach. [ABSTRACT FROM AUTHOR]

Versatility of solution-processing strategy based on the simultaneous rather than additive deposition of different functional molecules is discussed. It is shown that spin-cast polymer blends result in films with domains that could form elements with complementary functions of (i) solar cells, (ii) electronic circuitries, and (iii) test plates for protein micro-arrays: Alternating layers, rich in electron-donating polyfluorene and electron-accepting fullerene derivative, result in optimized solar power conversion. Surface patterns, made by soft lithography, align conductive paths of conjugated poly(3-alkylthiophene) in dielectric polystyrene. Proteins, preserving their biologically activity, are adsorbed to hydrophobic domains of polystyrene in hydrophilic matrix of poly(ethylene oxide). The authors report the research progress on structure formation in three polymer blend families, resulting in films with complementary elements for electronics and biotechnology. Blend film structures are determined with secondary ion mass spectrometry, atomic force microscopy, and fluorescence microscopy. In addition, the authors present recent results on (i) structure formation in fullerene derivative/poly(3-alkylthiophene) blends intended for solar cells, (ii) 3-dimensional SIMS imaging of conductive paths of poly(3-alkylthiophene) in dielectric polystyrene, (iii) test plates for multiprotein micro-arrays fabricated with blend films of hydrophobic polystyrene and thermoresponsive poly( N-isopropylacrylamide). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Background: The aim of the research presented here was to find a set of parameters enabling discrimination between three types of fibroblasts, i.e., healthy ones and those derived from two disorders mimicking each other: idiopathic pulmonary fibrosis (IPF), and nonspecific interstitial pneumonia (NSIP). Methods: The morphology and growth of cells were traced using fluorescence microscopy and analyzed quantitatively using cell proliferation and substrate cytotoxicity indices. The viability of cells was recorded using MTS assays, and their stiffness was examined using atomic force microscopy (AFM) working in force spectroscopy (FS) mode. To enhance any possible difference in the examined parameters, experiments were performed with cells cultured on substrates of different elasticities. Moreover, the chemical composition of cells was determined using time-of-flight secondary ion mass spectrometry (ToF-SIMS), combined with sophisticated analytical tools, i.e., Multivariate Curve Resolution (MCR) and Principal Component Analysis (PCA). Results: The obtained results demonstrate that discrimination between cell lines derived from healthy and diseased patients is possible based on the analysis of the growth of cells, as well as their physical and chemical properties. In turn, the comparative analysis of the cellular response to altered stiffness of the substrates enables the identification of each cell line, including distinguishing between IPF- and NSIP-derived fibroblasts. [ABSTRACT FROM AUTHOR]

In the present work, we have successfully prepared and characterized novel nanocomposite material exhibiting temperature-dependent surface wettability changes, based on grafted brush coatings of non-fouling poly(di(ethylene glycol)methyl ether methacrylate) (POEGMA) with the embedded CaCO3 nanoparticles. Grafted polymer brushes attached to the glass surface were prepared in a three-step process using atom transfer radical polymerization (ATRP). Subsequently, uniform CaCO3 nanoparticles (NPs) embedded in POEGMA-grafted brush coatings were synthesized using biomineralized precipitation from solutions of CaCl2 and Na2CO3. An impact of the low concentration of the embedded CaCO3 NPs on cell adhesion and growth depends strongly on the type of studied cell line: keratinocytes (HaCaT), melanoma (WM35) and osteoblastic (MC3T3-e1). Based on the temperature-responsive properties of grafted brush coatings and CaCO3 NPs acting as biologically active substrate, we hope that our research will lead to a new platform for tissue engineering with modified growth of the cells due to the release of biologically active substances from CaCO3 NPs and the ability to detach the cells in a controlled manner using temperature-induced changes of the brush. [ABSTRACT FROM AUTHOR]

The presented research aims to verify whether physicochemical properties of lung fibroblasts, modified by substrate stiffness, can be used to discriminate between normal and fibrotic cells from idiopathic pulmonary fibrosis (IPF). The impact of polydimethylsiloxane (PDMS) substrate stiffness on the physicochemical properties of normal (LL24) and IPF-derived lung fibroblasts (LL97A) was examined in detail. The growth and elasticity of cells were assessed using fluorescence microscopy and atomic force microscopy working in force spectroscopy mode, respectively. The number of fibroblasts, as well as their shape and the arrangement, strongly depends on the mechanical properties of the substrate. Moreover, normal fibroblasts remain more rigid as compared to their fibrotic counterparts, which may indicate the impairments of IPF-derived fibroblasts induced by the fibrosis process. The chemical properties of normal and IPF-derived lung fibroblasts inspected using time-of-flight secondary ion mass spectrometry, and analyzed complexly with principal component analysis (PCA), show a significant difference in the distribution of cholesterol and phospholipids. Based on the observed distinctions between healthy and fibrotic cells, the mechanical properties of cells may serve as prospective diagnostic biomarkers enabling fast and reliable identification of idiopathic pulmonary fibrosis (IPF). [ABSTRACT FROM AUTHOR]