Biocompatibility and Functional Performance of a Polyethylene Glycol Acid-Grafted Cellulosic Membrane for Hemodialysis

2000 ◽  
Vol 23 (6) ◽  
pp. 356-364 ◽  
Author(s):  
V. Sirolli ◽  
S. Di Stante ◽  
S. Stuard ◽  
L. Di Liberato ◽  
L. Amoroso ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Functional Performance ◽  
Sialyl Lewis X ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Dialysis Session ◽  
Cellulose Diacetate ◽  
Activation Markers ◽  
Surface Hydroxyl ◽  
Cellular Expression

In order to improve the biochemical reactivity of the cellulose polymer, which is mainly attributed to the presence of surface hydroxyl groups, derivatized cellulosic membranes have been engineered replacing or masking some or all of the hydroxyl groups in the manufacturing process of the membrane. The present study was set up to analyze both biocompatibility and functional performance of two different derivatized cellulosic membranes (cellulose diacetate; polyethylene glycol, PEG, acid-grafted cellulose) as compared to a synthetic membrane (polymethylmethacrylate, PMMA). Cellulose diacetate is prepared by substituting hydroxyl groups with acetyl groups; PEG cellulose is obtained by grafting PEG chains onto the cellulosic polymer with a smaller amount of substitution than cellulose diacetate. While the three dialyzers provided similar urea and creatinine removal, the dialyzer containing cellulose diacetate showed a reduced ability to remove β2-microglobulin compared to that containing PEG cellulose or PMMA. A transient reduction in leukocyte count was observed for both derivatized cellulosic membranes. The neutrophil and monocyte counts throughout the entire dialysis session showed a closer parallelism with the cellular expression of the adhesive receptor CD15s (sialyl-Lewis x molecole) than with CD11b/CD18 expression. Platelet activation, as indicated by the percentage of cells expressing the activation markers CD62P (P-selectin) and CD63 (gp53), occurred with all membranes at 15 min of dialysis and also with PMMA at 30 min. An increased formation of platelet-neutrophil and platelet-monocyte coaggregates was found at 15 and 30 min during dialysis with cellulose diacetate and PMMA but not with PEG cellulose. Generally in concomitance with the increase in platelet-neutrophil coaggregates, an increased hydrogen peroxide production by neutrophils occurred. Our results indicate that derivatizing cellulose may represent a useful approach to improve the biocompatibility of the cellulose polymer, though some homeostatic reactions remain activated. Our results also indicate that there may be a great variability in the biocompatibility profile of derivatized cellulosic membranes which most likely stem from the different type of structural modification rather than from the degree of hydroxyl group replacement.

The structure of an intercalated ordered kaolinite — a Raman microscopy study

Clay Minerals ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 587-596 ◽  
Author(s):  
R. L. Frost ◽  
T. H. Tran ◽  
J. Kristof
Keyword(s):  
Raman Band ◽  
Low Frequency ◽  
Potassium Acetate ◽  
Microscopy Study ◽  
Raman Microscopy ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Inner Surface ◽  
Order Of Magnitude

AbstractChanges in the molecular structure of a highly ordered kaolinite, intercalated with urea and potassium acetate, have been studied using Raman microscopy. A new Raman band, attributed to the inner surface hydroxyl groups strongly hydrogen bound to the acetate, is observed at 3605 cm-1 for the potassium acetate intercalate with the consequential loss of intensity in the bands at 3652, 3670, 3684 and 3693 cm-1. Remarkable changes in intensity of the Raman spectral bands of the low-frequency region of the kaolinite occurred upon intercalation. In particular, the 144 and 935 cm-1 bands increased by an order of magnitude and were found to be polarized. These spectroscopic changes provide evidence for the inner surface hydroxyl group-acetate bond being at an angle approaching 90° to the 001 face. Decreases in intensity of the bands at 243, 271 and 336 cm-1 were observed. The urea intercalate shows additional Raman bands at 3387, 3408 and 3500 cm-1 which are attributed to N-H vibrations after formation of the urea-kaolinite complex. Changes in the spectra of the inserting molecules were also observed.

AN INFRARED STUDY OF THE ADSORPTION OF AMMONIA ON POROUS VYCOR GLASS

1964 ◽  
Vol 42 (4) ◽  
pp. 802-809 ◽  
Author(s):  
N. W. Cant ◽  
L. H. Little
Keyword(s):  
Hydrogen Exchange ◽  
Lone Pair ◽  
Acid Sites ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Infrared Study ◽  
Vycor Glass ◽  
Oh Groups ◽  
Surface Hydroxyl ◽  
Adsorption Sites

The infrared spectrum of ammonia adsorbed on porous glass at 20 °C and 150 °C has been studied in the region 1450–4000 cm−1. No absorption band due to the asymmetric bending mode of ammonia was observed but in the NH stretching region, bands occurred at 3280 cm−1, 3320 cm−1, 3365 cm−1, and 3400 cm−1. The bands at 3320 cm−1 and 3400 cm−1 were easily removed by evacuation and are due to ammonia molecules hydrogen bonded through the nitrogen atom to surface hydroxyl groups. The bands at 3280 cm−1 and 3365 cm−1 were not removed by evacuation even at 150 °C and are due to ammonia molecules held to surface Lewis acid sites by the nitrogen lone-pair electrons. The site for this adsorption is not a surface hydroxyl group. These results are further evidence for the existence of the two adsorption sites proposed by Folman and Yates. Deuteration of the surface OH groups was easily accomplished with D2O vapor at 300 °C and the rate of hydrogen exchange between adsorbed ammonia molecules and surface OD groups was found to be rapid.

Chemical Stability of 2D-Nanostructured WO3 in Hydrogen Sensing Under Varied Operation Temperature

NANO ◽  
2016 ◽  
Vol 11 (08) ◽  
pp. 1650092 ◽  
Author(s):  
Taisheng Yang ◽  
Hui Tian ◽  
Yue Zhang ◽  
Chen Li
Keyword(s):  
Water Molecule ◽  
Chemical Stability ◽  
Density Functional ◽  
Stable State ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Hydrogen Sensing ◽  
Operation Temperature ◽  
Surface Hydroxyl Groups

Nanostructured metal oxide-based resistive-type gas sensors are of high research interest. Chemical stability is the most critical issue due to the surface electron species and density. In the present paper, 2D-nanostructured WO3 was prepared and characterized, and a WO3-based sensor was fabricated and analyzed. The results showed that the synthesized WO3 material exhibited nanosheet structure, and during hydrogen sensing testing, the current baseline shifted with various tendencies, even completely opposite directions under different operation temperatures. The chemistry analysis results indicated that water molecule and hydroxyl group were formed under low operation temperature but further oxidation occurred at higher temperatures. The adsorption of H2 on oxygen terminated WO3(0 0 1) surfaces by density functional theory (DFT) method indicated that a water molecule formed by adsorption of a hydrogen molecule at the O site with the most thermodynamically stable state, and two surface hydroxyl groups formed by dissociative adsorption with a thermodynamically less stable state. The water molecule and surface hydroxyl groups increased the conductivity of the WO3 film while that was decreased as the oxidation occurred.

scholarly journals Tailoring the component of protein corona via simple chemistry

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiang Lu ◽  
Peipei Xu ◽  
Hong-Ming Ding ◽  
You-Sheng Yu ◽  
Da Huo ◽  
...  
Keyword(s):  
Surface Properties ◽  
Blood Circulation ◽  
Molecular Simulations ◽  
Protein Corona ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
In Vitro Measurements

Abstract Control over the protein corona of nanomaterials allows them to function better. Here, by taking graphene/gold as examples, we comprehensively assessed the association of surface properties with the protein corona. As revealed by in vitro measurements and computations, the interaction between graphene/gold and HSA/IgE was inversely correlated with the hydroxyl group availability, whereas the interaction between that and ApoE was comparatively less relevant. Molecular simulations revealed that the number and the distribution of surface hydroxyl groups could regulate the manner in which nanomaterials interact with proteins. Moreover, we validated that ApoE pre-adsorption before injection enhances the blood circulation of nanomaterials relative to their pristine and IgE-coated counterparts. This benefit can be attributed to the invulnerability of the complementary system provided by ApoE, whose encasement does not increase cytotoxicity. Overall, this study offers a robust yet simple way to create protein corona enriched in dysopsonins to realize better delivery efficacy.

scholarly journals Defluoridation performance comparison of aluminum hydroxides with different crystalline phases

2022 ◽  
Author(s):  
Wei-Zhuo Gai ◽  
Shi-Hu Zhang ◽  
Yang Yang ◽  
Kexi Sun ◽  
Hong Jia ◽  
...  
Keyword(s):  
Aluminum Hydroxide ◽  
Performance Comparison ◽  
Hydroxyl Group ◽  
Fluoride Removal ◽  
Hydroxyl Groups ◽  
Order Kinetic ◽  
Crystalline Phases ◽  
Surface Hydroxyl ◽  
Ph Values ◽  
Aluminum Hydroxides

Abstract Aluminum hydroxide is an eye catching and extensively researched adsorbent for fluoride removal and its defluoridation performance is closely related to the preparation method and crystalline phase. In this research, the defluoridation performances of aluminum hydroxides with different crystalline phases are compared and evaluated in terms of fluoride removal capacity, sensitivity to pH values and residual Al contents after defluoridation. It is found that the defluoridation performance of different aluminum hydroxides follows the order of boehmite > bayerite > gibbsite. The fluoride adsorption on aluminum hydroxides follows pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum defluoridation capacities of boehmite, bayerite and gibbsite are 42.08, 2.97 and 2.74 mg m−2, respectively. The pH values and FTIR analyses reveal that the ligand exchange between fluoride and surface hydroxyl groups is the fluoride removal mechanism. Different aluminum hydroxides have different surface hydroxyl group densities, which results in the different defluoridation capacities. This work provides a new idea to prepare aluminum hydroxide with outstanding defluoridation performance.

The synthesis and structure of silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complexes

1986 ◽  
Vol 51 (7) ◽  
pp. 1430-1438 ◽  
Author(s):  
Alena Reissová ◽  
Zdeněk Bastl ◽  
Martin Čapka
Keyword(s):  
Free Surface ◽  
Hydroxyl Groups ◽  
Titanium Complex ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Cyclopentadienyl Anion

The title complexes have been obtained by functionalization of silica with cyclopentadienylsilanes of the type Rx(CH3)3 - xSi(CH2)nC5H5 (x = 1-3, n = 0, 1, 3), trimethylsilylation of free surface hydroxyl groups, transformation of the bonded cyclopentadienyl group to the cyclopentadienyl anion, followed by coordination of (h5-cyclopentadienyl)trichlorotitanium. The effects of single steps of the above immobilization on texture of the support, the number of free hydroxyl groups, the coverage of the surface by cyclopentadienyl groups and the degree of their utilization in anchoring the titanium complex have been investigated. ESCA study has shown that the above anchoring leads to formation of the silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complex.

scholarly journals Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2131
Author(s):  
Leonardo Dalseno Antonino ◽  
Júlia Rocha Gouveia ◽  
Rogério Ramos de Sousa Júnior ◽  
Guilherme Elias Saltarelli Garcia ◽  
Luara Carneiro Gobbo ◽  
...  
Keyword(s):  
Experimental Work ◽  
Chemical Structure ◽  
31P Nmr ◽  
Kraft Lignin ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Diphenylmethane Diisocyanate ◽  
Complex Chemical ◽  
Heterogeneous Reactivity ◽  
Phenolic Hydroxyl Groups

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

scholarly journals Enhancement of Antioxidant and Hydrophobic Properties of Alginate via Aromatic Derivatization: Preparation, Characterization, and Evaluation

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2575
Author(s):  
Smaher M. Elbayomi ◽  
Haili Wang ◽  
Tamer M. Tamer ◽  
Yezi You
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Benzoyl Group ◽  
Antioxidant Evaluation ◽  
Thermo Stability

The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

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