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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]

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]

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]

Abstract We characterize an approach enabling dual protein positioning over broad polymer areas based on subsequent selective adsorption of two fluorescently labelled lectins, Concanavalin A (Con A) and Lentil Lectin (LcH), on self-assembled gradient patterns of thermoresponsive poly(N-isopropyl acrylamide) (PNIPAM) and polystyrene (PS) polymers blend, prepared by horizontal dipping technique. The film morphologies of gradient samples prior dual selective protein adsorption are mapped with scanning microscopy (AFM) and secondary ion mass spectrometry (ToF-SIMS), whereas adsorbed proteins are imaged with fluorescence microscope. ToF-SIMS analysis reveals surface composition consisting of PNIPAM-rich domains in PS-rich matrix. The two-step protein adsorption experiment results in selective adsorption of Con A and LcH to PNIPAM- and PS-rich phases, respectively. Integral geometry approach is used to compare quantitatively morphology of polymer patterns varied in domain size due to horizontal dipping casting. Minkowski measures are also used to compare quantitatively fluorescence micrographs of protein patches with SIMS images of original isotropic polymer patterns. It confirms that PNIPAM domains size increases with increasing speed. Further, Minkowski analysis unveiled that adsorbed proteins cover about 60–70% of polymer surface. What is more fluorescence micrographs acknowledge both no lectins contamination and no adsorption to interphase areas. Additionally, protein displacement effect is observed. Graphical abstract Unlabelled Image Highlights • Gradient patterns of thermoresponsive polymer as supports for dual protein positioning. • Subsequent lectin adsorption allows fabrication of dual protein patterns. • Proteins displacement events were observed. • 'Protein affinity' is one of key factors responsible for the Vroman-like effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • Application of poly(4-vinyl pyridine) layers cross-linked with transition metal complexes as active layers in biomedical sensors. • Sensitivity of the coatings to the presence of proteins and cells in different concentrations verified by impedance spectroscopy. • Different detection limits for different transition metals. • High selectivity of the coatings toward the defined analyte confirmed by the specific antigen–antibody immunoreaction. • Conductive response of a bilayer system that mimics Organic Field Effect Transistor. The possibility of application of poly(4-vinyl pyridine) layers cross-linked with transition metal complexes as active layers in biomedical sensors was tested. The successful modification of the P4VP coating with CuBr 2 or ZnBr 2 was verified using time of flight - secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The topography and wettability of the coatings were examined by using atomic force microscopy and water contact angles measurements, respectively. Tests of biological activity of coatings indicated strong protein adsorption, good biocompatibility, and no antimicrobial activity. The potential of the coatings to be used as active layers of biosensors was verified, by systematic impedance-based measurements, which showed the sensitivity of the P4VP:CuBr 2 coatings to the presence of proteins and cells in different concentrations. The high selectivity of the coatings toward the defined analyte was confirmed by the specific antigen–antibody immunoreaction, and the possibility of in situ monitoring of protein adsorption and cell adhesion also for individual cells was presented. Finally, the conductive response of a bilayer system that mimics Organic Field Effect Transistor was shown. These results point to a great potential for both coatings to serve as active layers of sensitive and highly selective biosensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Architecture of PS-PGL copolymers influences its properties in thin films. • Copolymer with coil-brush structure reorients PGL segments in aqueous solution. • Reorientation of PGL chains to the film surface significantly reduces BSA adsorption. • Protein molecules due to adsorption to polymer film reduce mobility of polymer blocks. The effect of the architecture of amphiphilic polystyrene-b-polyglycidol and polystyrene-b-(polyglycidol-g-polyglycidol) copolymers on their behavior in thin films and interaction with the protein has been studied. The properties of the copolymer films surface were investigated before and after incubation in water and aqueous solution of PBS buffer. Surface sensitive techniques: time-of-flight secondary ion mass spectrometry, atomic force microscopy, and contact angle measurements show the differences in film surfaces behavior depending on the copolymer architecture. It was found that exposure of the coil-brush copolymer to an aqueous solution reoriented the PGL segments, changing the properties of the surface layer. Greater exposure of antifouling PGL chains at the surface of the copolymer film modified the interaction with bovine serum albumin, significantly reducing its adsorption. In contrast, no changes in the orientation of the PGL chains were observed after incubation of the copolymer films in an aqueous solution of protein in PBS buffer. This suggests that protein adsorption to the thin copolymer film blocks the conformational changes of the copolymer chains and reduces their mobility under the protein molecules. [ABSTRACT FROM AUTHOR]

The methods of preparation and characterization of core-shell poly(styrene/α- tert -butoxy-ω-vinylbenzyl-polyglycidol) particles arranged in colloidal crystals are described. The particles were prepared via emulsifier free emulsion copolymerization of styrene and α- tert -butoxy-ω-vinylbenzyl-polyglycidol macromonomer in aqueous medium, initiated by potassium persulfate. The individual polymerizations differed in a way of addition of macromonomer to the polymerization mixture. The particles assemblies were characterized by atomic force microscopy, Secondary Ion Mass Spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS). In-depth distribution of chemical states was determined by XPS combined with argon gas cluster ion sputtering (Ar-GCIB). The morphology of microspheres assemblies reflected the composition of the entire particles. It was found that the method of macromonomer addition to the polymerization mixture affects the particles size, surface and overall morphology. The XPS profiles revealed the chemical composition of the particles arranged in multilayers. It was found that distribution of polyglycidol segments at the particles interfacial layer depends on the time and way of addition of macromonomer. The thickest outer layer composed from polystyrene-polyglycidol segments was obtained for particles when macromonomer was added at the beginning of polymerization. [ABSTRACT FROM AUTHOR]

The impact of polymer stereoregularity on its interactions with peptides, proteins and bacteria strains was studied for three stereoregular forms of poly(tert-butyl methacrylate) (PtBMA): isotactic (iso), atactic (at) and syndiotactic (syn) PtBMA. Principal component analysis of the time-of-flight secondary ion mass spectrometry data recorded for thin polymer films indicated a different orientation of ester groups, which in the case of iso-PtBMA are exposed away from the surface whereas for at-PtBMA and syn-PtBMA these are located deeper within the film. This arrangement of chemical groups modified the interactions of iso-PtBMA with biomolecules when compared to at-PtBMA and syn-PtBMA. For peptides, the affected interactions were explained by the preferential hydrogen bonding and electrostatic interaction between the exposed polar ester groups of iso-PtBMA and positively charged peptides. In turn, for protein adsorption no impact on the amount of adsorbed proteins was observed. However, the polymer stereoregularity influenced the orientation of immunoglobulin G and induced conformational changes in bovine serum albumin structure. Moreover, the impact of polymer stereoregularity occurred equally for their interactions with Gram-positive bacteria (S. aureus) , which absorbed preferentially onto iso-PtBMA films as compared to two other stereoregularities. [Display omitted] • properties of polymer film surface can be modified by stereoregularity of polymer. • isotactic PtBMA expose more polar ester groups at the surface. • tacticity of polymer impact on conformation and orientation of adsorbed proteins. • presence of ester groups at the surface of iso-PtBMA modified bacterial adhesion. [ABSTRACT FROM AUTHOR]

• Aminosilane layer micropatterned with photolithography and oxygen plasma. • Selective adsorption of contact printed biotinylated-BSA onto the APTES stripes. • Step-by-step chemical imaging of APTES patterning and biofunctionalization. • Blocking the surface with BSA results in binary protein pattern. • Patterning demonstrated for on-chip interferometric biosensors detecting streptavidin. Time-of-flight secondary ion mass spectrometry has been employed to characterize micropatterning of aminosilane layer by photolithography and oxygen plasma treatment to achieve spatially selective biofunctionalization of Si 3 N 4 waveguides surface corresponding to the sensing arm area of Mach-Zehnder interferometric biosensors integrated on silicon-chip. Si 3 N 4 surface with (3-aminopropyl)triethoxysilane (APTES) layer was examined after photolithography, plasma treatment, photoresist removal, and after robotic spotting with biotinylated bovine serum albumin (BSA), blocking with BSA and specific binding of streptavidin. TOF-SIMS chemical imaging and microanalysis provided an inside view regarding the resolution and selectivity of surface modification after each step of both the APTES layer patterning and biofunctionalization procedures. More particular, the effective APTES removal and surface oxidization to create 20-µm wide APTES stripes through photolithography and oxygen plasma treatment was demonstrated. Exclusive adsorption of biotinylated-BSA on the APTES stripes through spotting of the patterned surface is then revealed, followed by a preferential but not exclusive BSA adsorption during the blocking step. The pattern was clearly developed through exclusive streptavidin binding to biotinylated-BSA only onto the APTES regions. The proposed spatially-selective biofunctionalization, performed with biotinylated-BSA, was demonstrated for the Si 3 N 4 waveguide surface of an integrated on chip interferometric biosensor sensing arm for the detection of streptavidin. [ABSTRACT FROM AUTHOR]