AFM imaging and analysis of local mechanical properties for detection of surface pattern of functional groups

et al. 2016

Electrochimica Acta

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In this contribution, various Ti thin substrates were explored and compared for the anodic growth of self-organized TiO 2 nanotube layers for the first time. In order to evaluate differences in the electrochemical anodization characteristics and the tube dimensions, five different Ti substrates from four established suppliers were anodized in the widely used ethylene glycol electrolytes containing 88 mM NH 4 F and 1,5 vol.% water. Two anodizations were carried out to elucidate an influence of the pre-anodized substrates used for the second anodization. By thorough evaluation of the nanotube dimensions, large variations between the dimensions of the nanotubes were found for the different substrates, ranging from ~32 µm to ~50 µm for the nanotube length and from ~109 nm to ~127 nm for the nanotube diameter after the second anodization. Upon AFM measurements, Goodfellow Ti substrates (99.99 % purity), yielded the smoothest surface and the highest degree of ordering from all substrates.Moreover, considerably different consumption of Ti substrates via anodization was revealed by profilometric measurements between the original non-anodized part of the Ti substrates, and the anodized part after the removal of the nanotube layer. Orientation imaging 2 microscopy revealed considerable differences in the size and orientation of the substrate grains.

Section: Methodsmentioning

confidence: 99%

Self-organized Anodic TiO2 Nanotube Layers: Influence of the Ti substrate on Nanotube Growth and Dimensions

Sopha

Jäger

et al. 2016

Electrochimica Acta

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“…The mechanical behaviour and thickness of the water layer on the surface of the naked/HA-coated Dynabeads M-270 Amine particles were analysed in force-spectroscopy mode [28,29]. The stiffness expressed by the slope of curves (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The topography and force spectroscopy modes of the AFM were executed using the Solver Pro M instrument (NT-MDT, St. Peterburg, Russia). Data for diameter, topography and force spectroscopy were determined according to procedures described previously [27][28][29].…”

Section: Sem and Afm Measurementmentioning

confidence: 99%

Magnetic microparticles post-synthetically coated by hyaluronic acid as an enhanced carrier for microfluidic bioanalysis

Holubová

Materials Science and Engineering: C

Palarčík

et al. 2014

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Iron oxide based particles functionalized by bioactive molecules have been utilized extensively in biotechnology and biomedicine. Despite their already proven advantages, instability under changing reaction conditions, non-specific sorption of biomolecules on the particles' surfaces, and iron oxide leakage from the naked particles can greatly limit their application. As confirmed many times, surface treatment with an appropriate stabilizer helps to minimize these disadvantages. In this work, we describe enhanced post-synthetic surface modification of superparamagnetic microparticles varying in materials and size using hyaluronic acid (HA) in various chain lengths. Scanning electron microscopy, atomic force microscopy, phase analysis light scattering and laser diffraction are the methods used for characterization of HA-coated particles. The zeta potential and thickness of HA-layer of HA-coated Dynabeads M270 Amine were -50 mV and 85 nm, respectively, and of HA-coated p(GMA-MOEAA)-NH2 were -38 mV and 140 nm, respectively. The electrochemical analysis confirmed the zero leakage of magnetic material and no reactivity of particles with hydrogen peroxide. The rate of non-specific sorption of bovine serum albumin was reduced up to 50% of naked ones. The coating efficiency and suitability of biopolymer-based microparticles for magnetically active microfluidic devices was confirmed. Highlights: Post-synthetic surface modification of magnetic microparticles by hyaluronic acid  Hyaluronic acid -polymer of unique physicochemical and biological characteristics ABSTRACTIron oxide based particles functionalized by bioactive molecules have been utilized extensively in biotechnology and biomedicine. Despite their already proven advantages, instability under changing reaction conditions, non-specific sorption of biomolecules on the particles' surfaces, and iron oxide leakage from the naked particles can greatly limit their application. As confirmed many times, surface treatment with an appropriate stabilizer helps to minimize these disadvantages.In this work, we describe enhanced post-synthetic surface modification of superparamagnetic microparticles varying in materials and size using hyaluronic acid (HA) in various chain lengths. Scanning electron microscopy, atomic force microscopy, phase analysis light scattering and laser diffraction are the methods used for characterization of HA-coated particles. The zeta potential and thickness of HA-layer of HA-coated Dynabeads M270Amine were -50 mV and 85 nm, respectively, and of HA-coated p(GMA-MOEAA)-NH 2 were -38 mV and 140 nm, respectively. The electrochemical analysis confirmed the zero leakage of magnetic material and no reactivity of particles with hydrogen peroxide. The rate of nonspecific sorption of bovine serum albumin was reduced up to 50% of naked ones. The coating efficiency and suitability of biopolymer-based microparticles for magnetically active microfluidic devices was confirmed.

“…This technique offered an efficient and non-destructive quantitative estimation of the topography, elasticity, viscoelasticity, and stiffness from the upper part of the individual fibre (25). The comparison of the mechanical behaviour was based on the determination of the linear part of the retractive force of the tip during indentation of the material proportional to the nanoindentation stiffness/hardness (18,26). Thin fibres (below 100 nm) could be stiffer as the measurement is influenced by the substrate during indentation or swelling by the air humidity.…”

Section: Discussionmentioning

confidence: 99%

Aligned nanofibres made of poly(3-hydroxybutyrate) grafted to hyaluronan for potential healthcare applications

Huerta-Ángeles

Knotková

et al. 2018

J Mater Sci: Mater Med

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In this work, a hybrid copolymer consisting of poly(3-hydroxybutyrate) grafted to hyaluronic acid (HA) was synthesised and characterised. Once formed, the P(3HB)-g-HA copolymer was soluble in water allowing a green electrospinning process. The diameters of nanofibres can be tailored by simply varying the M of polymer. The optimization of the process allowed to produce fibres of average diameter in the range of 100-150 nm and low polydispersity. The hydrophobic modification has not only increased the fibre diameter, but also the obtained layers were homogenous. At the nanoscale, the hybrid copolymer exhibited an unusual hairy topography. Moreover, the hardness and tensile properties of the hybrid were found to be superior compared to fibres made of unmodified HA. Particularly, this reinforcement was achieved at the longitudinal direction. Additionally, this work reports the use in the composition of a water-soluble copolymer containing photo cross-linkable moieties to produce insoluble materials post-electrospinning. The derivatives as well as their nanofibrous mats retain the biocompatibility of the natural polymers used for the fabrication.