A comparison of the physical and chemical differences between cancellous and cortical bovine bone mineral at two ages

To assess possible differences between the mineral phases of cortical and cancellous bone, the structure and composition of isolated bovine mineral crystals from young (1–3 months) and old (4–5 years) postnatal bovine animals were analyzed by a variety of complementary techniques: chemical analyses, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and 31P solid-state magic angle spinning nuclear magnetic resonance spectroscopy (NMR). This combination of methods represents the most complete physicochemical characterization of cancellous and cortical bone mineral completed thus far. Spectra obtained from XRD, FTIR, and 31P NMR all confirmed that the mineral was calcium phosphate in the form of carbonated apatite; however, a crystal maturation process was evident between the young and old and between cancellous and cortical mineral crystals. Two-way analyses of variance showed larger increases of crystal size and Ca/P ratio for the cortical vs. cancellous bone of 1–3 month than the 4–5 year animals. The Ca/(P + CO3) remained nearly constant within a given bone type and in both bone types at 4–5 years. The carbonate and phosphate FTIR band ratios revealed a decrease of labile ions with age and in cortical, relative to cancellous, bone. Overall, the same aging or maturation trends were observed for young vs. old and cancellous vs. cortical. Based on the larger proportion of newly formed bone in cancellous bone relative to cortical bone, the major differences between the cancellous and cortical mineral crystals must be ascribed to differences in average age of the crystals

Biomimetic self-assembling copolymer-hydroxyapatite nanocomposites with the nanocrystal size controlled by citrate

Citrate binds strongly to the surface of calcium phosphate (apatite) nanocrystals in bone and is thought to prevent crystal thickening. In this work, citrate added as a regulatory element enabled molecular control of the size and stability of hydroxyapatite (HAp) nanocrystals in synthetic nanocomposites, fabricated with self-assembling block copolymer templates. The decrease of the HAp crystal size within the polymer matrix with increasing citrate concentration was documented by solid-state nuclear magnetic resonance (NMR) techniques and wide-angle X-ray diffraction (XRD), while the shapes of HAp nanocrystals were determined by transmission electron microscopy (TEM). Advanced NMR techniques were used to characterize the interfacial species and reveal enhanced interactions between mineral and organic matrix, concomitant with the size effects. The surface-to-volume ratios determined by NMR spectroscopy and long-range 31P{1H} dipolar dephasing show that 2, 10, and 40 mM citrate changes the thicknesses of the HAp crystals from 4 nm without citrate to 2.9, 2.8, and 2.3 nm, respectively. With citrate concentrations comparable to those in body fluids, HAp nanocrystals of sizes and morphologies similar to those in avian and bovine bones have been produced

Visualisation of Liquid Flow Phenomena in Textiles Applied as a Wound Dressing

Abstract The aim of this work was to visualise liquid transport in textiles. Knowledge of the transport phenomena allows for the design of textiles for various applications, e.g., comfortable to wear filtration and wound dressing. To visualise liquid transport through textiles, three test methods were explored. The first one was the high spatial resolution magnetic resonance imaging (MRI) technique (also referred to as nuclear magnetic resonance (NMR) microscopy). It allowed the observation of the pathways of liquid flow through textiles. In the second method, a thermographic camera was used to record temperature changes and assess the liquid flow in the textile. The third method was using a high-speed video camera to observe the liquid transport within the textile. Two types of textiles were studied: a double-layer knitted fabric and a woven fabric, both made from hydrophilic and hydrophobic fibres (cotton, viscose and polypropylene). The knitted fabrics were tested as a new type of wound dressing, which trans</jats:p