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Wang Z.X.,Cornell University | Lloyd A.A.,Cornell University | Burket J.C.,Hospital for Special Surgery | Gourion-Arsiquaud S.,TRI Princeton | Donnelly E.,Cornell University
Bone | Year: 2016

Heterogeneity of bone tissue properties is emerging as a potential indicator of altered bone quality in pathologic tissue. The objective of this study was to compare the distributions of tissue properties in women with and without histories of fragility fractures using Fourier transform infrared (FTIR) imaging. We extended a prior study that examined the relationship of the mean FTIR properties to fracture risk by analyzing in detail the widths and the tails of the distributions of FTIR properties in biopsies from fracture and non-fracture cohorts. The mineral and matrix properties of cortical and trabecular iliac crest tissue were compared in biopsies from women with a history of fragility fracture (+ Fx; n = 21, age: mean 54 ± SD 15 y) and with no history of fragility fracture (- Fx; n = 12, age: 57 ± 5 y). A subset of the patients included in the - Fx group were taking estrogen-plus-progestin hormone replacement therapy (HRT) (- Fx + HRT n = 8, age: 58 ± 5 y) and were analyzed separately from patients with no history of HRT (- Fx - HRT n = 4, age: 56 ± 7 y). When the FTIR parameter mean values were examined by treatment group, the trabecular tissue of - Fx - HRT patients had a lower mineral:matrix ratio (M:M) and collagen maturity (XLR) than that of - Fx + HRT patients (- 22% M:M, - 18% XLR) and + Fx patients (- 17% M:M, - 18% XLR). Across multiple FTIR parameters, tissue from the - Fx - HRT group had smaller low-tail (5th percentile) values than that from the - Fx + HRT or + Fx groups. In trabecular collagen maturity and crystallinity (XST), the - Fx - HRT group had smaller low-tail values than those in the -Fx + HRT group (- 16% XLR, - 5% XST) and the + Fx group (- 17% XLR, - 7% XST). The relatively low values of trabecular mineral:matrix ratio and collagen maturity and smaller low-tail values of collagen maturity and crystallinity observed in the - Fx - HRT group are characteristic of younger tissue. Taken together, our data suggest that the presence of newly formed tissue that includes small/imperfect crystals and immature crosslinks, as well as moderately mature tissue, is an important characteristic of healthy, fracture-resistant bone. Finally, the larger mean and low-tail values of mineral:matrix ratio and collagen maturity noted in our - Fx + HRT vs. - Fx - HRT biopsies are consistent with greater tissue age and greater BMD arising from decreased osteoclastic resorption in HRT-treated patients. © 2016. Source

Lewitus D.Y.,New Jersey Center for Biomaterials | Landers J.,Rutgers University | Branch J.R.,New Jersey Center for Biomaterials | Smith K.L.,New York State Department of Health | And 3 more authors.
Advanced Functional Materials | Year: 2011

A novel approach for producing carbon nanotube fibers (CNF) composed with the polysaccharide agarose is reported. Current attempts to make CNFs require the use of a polymer or precipitating agent in the coagulating bath that may have negative effects in biomedical applications. It is shown that, by taking advantage of the gelation properties of agarose, one can substitute the bath with distilled water or ethanol and, hence, reduce the complexity associated with alternating the bath components or the use of organic solvents. It is also demonstrated that these CNF can be chemically functionalized to express biological moieties through available free hydroxyl groups in agarose. Agarose CNF are not only conductive and nontoxic; in addition, their functionalization is shown to facilitate cell attachment and response both in vitro and in vivo. Our findings suggest that agarose/CNT hybrid materials are excellent candidates for applications involving neural tissue engineering and biointerfacing with the nervous system. A novel approach for producing carbon nanotube fibers (CNF) composed with the polysaccharide agarose is reported. The TOC image shows representative immunohistochemical images of rat brain slices after insertion of CNT/agarose fiber-electrodes. Cell types shown are microglia (blue), astrocytes (orange), and neurons (green). A is a control electrode and B is an electrode functionalized with laminin, a neural extracellular matrix protein. Close inspection and quantification of the cell response reveals favorable tissue reaction to the laminin tethered electrode. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Gourion-Arsiquaud S.,TRI Princeton | Hu Q.,Anasys Instruments Corp. | Boskey A.L.,Mineralized Tissue Laboratory
Calcified Tissue International | Year: 2014

Bone has a hierarchical structure extending from the micrometer to the nanometer scale. We report here the first analysis of non-human primate osteonal bone obtained using a spectrometer coupled to an AFM microscope (AFM-IR), with a resolution of 50–100 nm. Average spectra correspond to those observed with conventional FTIR spectroscopy. The following validated FTIR parameters were calculated based on intensities observed in scans covering ~60 µm from the osteon center: mineral content (1030/1660 cm−1), crystallinity (1030/1020 cm−1), collagen maturity (1660/1690 cm−1), and acid phosphate content (1128/1096 cm−1). A repeating pattern was found in most of these calculated IR parameters corresponding to the reported inter- and intra-lamellar spacing in human bone, indicating that AFM-IR measurements will be able to provide novel compositional information on the variation in bone at the nanometer level. © 2014, Springer Science+Business Media New York. Source

Callegari G.,TRI Princeton | Tyomkin I.,TRI Princeton | Kornev K.G.,Clemson University | Neimark A.V.,Rutgers University | Hsieh Y.-L.,University of California at Davis
Journal of Colloid and Interface Science | Year: 2011

Characterization of transport and absorption properties of nanofiber webs is a challenge, because in many cases the material is soft and cannot withstand the stresses exerted by the standard instruments. In this paper, we report on development of a new technique for materials characterization. We propose to conduct wicking and permeability experiments for full characterization of the nanowebs. As an example, we used electrospun cellulose acetate nanowebs. The wicking experiments showed very good reproducibility, demonstrating the square-root-of-time dependence of wetting front position vs time. The prefactor depends on a product of capillary pressure and materials permeability. We developed a technique to independently measure the permeability of small samples of nanowebs. Wicking and permeability data allow one to estimate the pore size; SEM micrographs confirmed the obtained estimates of pore radius. In general, the proposed method allows one to characterize the transport and absorption parameters of the nanofibrous materials for which the standard procedures are inapplicable. © 2010 Elsevier Inc. Source

Kamath Y.K.,TRI Princeton | Kamath Y.K.,Kamath Consulting Inc. | Ruetsch S.B.,TRI Princeton
Journal of Cosmetic Science | Year: 2010

A microfluorometric method has been developed to characterize lipid removal or "delipidation" of the human hair cuticula during light exposure and chemical grooming processes such as oxidation (bleaching) and reduction. In the case of photochemical and chemical oxidation, lipid removal ("delipidation" of the F-layer or lipid-layer) from the outer β-layer of the exposed scale faces and generation of cysteic acid groups occurs. This "delipidation," which ultimately results in "acidification" of the scale faces, leading to a change in surface chemistry from hydrophobic to hydrophilic, can be detected and quantified by microfluorometry by tagging, e.g., with the cationic fluorochrome Rhodamine B. In the case of reduction, similar tagging of the acid sites on the scale faces is possible, but this time, Rhodamine B reacts with the mixed disulfide containing a carboxyl group that will be ionized above a pH of about 4. In addition to this, we have shown by microfluorometric scanning that the negative charges generated in the cuticle surface can be used to bind low-molecular-weight quaternary conditioners. This process can be considered as "relipidation" or "refatting" of the scale faces. We have shown in earlier studies (1) that this entire process of oxidation-induced "delipidation" and subsequent "relipidation" of the acidic scale faces with a cationic conditioning molecule can also be reliably quantified by X-ray photoelectron spectroscopy (XPS). Furthermore, single-fiber wettability scanning using the Wilhelmy technique, which is highly sensitive to any changes in surface chemistry, is well-suited to detect and characterize treatment-induced changes in the chemical nature of the hair surface from hydrophobic to hydrophilic. Source

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