ESCA Research Articles

Comparison of Bonds Existing Between C60 Fullerene and Polyamide Molecules in Various Nanocomposite Materials

Fullerene–polymer composites may find applications in different areas, particularly, in membrane technology. The formation of bonds between molecules of C60 fullerene and poly(phenylene isophtalamide) (PA) in PA-C60 composites was investigated. Powder-like PA-C60 mixtures, ultrafiltration membranes and nonporous thin films were studied by extracting C60 from the samples with various solvents. It was found that two types of fullerene coexist in the studied composites: the free (easily extractable) fullerene and the bound molecules. The percentage of extractable C60 in a given sample depends on sample composition and the method used for obtaining this nanocomposite material. An important factor in increasing the C60-PA bond strength is the duration of the material formation procedure. The quantitative processing of digital photographs of membranes, scanning electron microscopy (SEM), and electron spectroscopy for chemical analysis (ESCA) data showed that the free C60 is mainly located close to the active membrane surface. The bound C60 molecules are distributed throughout the membranes and films.

Effect of evidence-based nursing on self-care agency and self-efficacy in colostomy patients

Objective To explore the effect of evidence-based nursing on self-care agency and self-efficacy in colostomy patients. Methods A total of ninety four patients with permanent colostomy, who had taken the Miles operation during November 2010 to November 2013, were randomly divided into two groups on average: experimental group and control group. Data of forty seven patients underwent evidence-based nursing were compared by ESCA and GSES after admission and before discharge with the control group of forty seven patients who had been given routine nursing care during the same period. Results The total scores of self-nursing ability were (105.51±8.53) and (112.70±8.19), and the scores of self-efficacy were (2.25±0.56) and (2.79±0.58) in the experimental group after intervention with statistically significant between two groups (t=4.170, 4.555, respectively; P 0.05). Conclusions Evidence-based nursing method could improve the colostomy patients′ self-nursing ability and self-efficacy, and enhance the level of physical and mental health. Key words: Colostomy; Evidence-based nursing; Self-care agency; Self-efficacy

Biosynthesis and in vitro evaluation of macroporous mineralized bacterial nanocellulose scaffolds for bone tissue engineering

Macroporous bacterial nanocellulose (BNC) scaffolds with calcium phosphate coated surfaces is a candidate for future bone tissue engineering applications. The mineralization of the macroporous BNC scaffolds was achieved by a biomimetic process, resulting in an environment resembling native bone tissues' mineralized extra cellular matrix both topographically and chemically. The deposited crystals were analyzed with electron spectroscopy for chemical analysis (ESCA), energy-dispersive X-ray spectroscopy (EDX) and X-ray crystallography (XRD). MSCs were cultured in osteogeneic medium for 21 days on the scaffolds. The results of this study show that macroporous BNC can be mineralized with hydroxyapatite and that MSCs retain their ability to proliferate and differentiate towards an osteoblastic phenotype within the mineralized BNC, showing the promise of this material in bone tissue engineering applications.

Fabrication and characterization of CaP-coated nanotube arrays

Modified anodization techniques have been shown to improve the biocompatibility of titanium. This study demonstrated the anodic formation of self-organized nanotube arrays on titanium from an electrolyte solution containing 1 M H3PO4 and 1 wt% hydrofluoric acid (HF). Our aim was to investigate the effects of sputter-deposited CaP on nanotube arrays. SEM images revealed a surface with uniform morphology and an average pore diameter of 29 nm. XRD results indicated that the phase of the nanotube arrays was amorphous. Electron spectroscopy for chemical analysis (ESCA) confirmed that the nanotube arrays were coated with calcium and phosphorus. Cell culture experiments using human osteosarcoma (HOS) cells demonstrated that the CaP/nanotube arrays had a pronounced effect on initial cell attachment as well as on the number of cells at 1, 7, and 14 days. Compared to as-polished titanium, the CaP/nanotube arrays accelerated cell proliferation, attachment, and spreading. Our results demonstrate the pronounced effects of CaP/nanotube arrays on the biological responses of HOS cells.

Preparation of superhydrophobic polyimide films modified with organosilicasol as effective anticorrosion coatings

In this study we prepared superhydrophobic polyimide (PI) hybrid coatings for anticorrosion application by adjusting their surface roughness and surface composition through spray-coating with silylated perfluoroalkylsilane-modified organosilicasol (silylated fluoro-organosilicasol), which increased the surface hydrophobicity. After silylation with 1,1,1,3,3,3-hexamethyldisilazane (HMDS), the silylated fluoro-organosilicasol further transformed the PI surface into a superhydrophobic state with a static water contact angle of greater than 160° and a low hysteresis of 10°. We examined the mechanism behind the enhancement in superhydrophobicity through analyses of the surface topology and chemical composition of the films, using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electron spectroscopy for chemical analysis (ESCA). These analyses suggested that both surface roughness and silylation of the fluoro-organosilicasol making more CF2 groups on the outmost surface rendered the surface hydrophobicity. The anticorrosion properties of these superhydrophobic coatings were also examined through Tafel measurement. These PI hybrid coatings demonstrated lower corrosion current density and nobler corrosion potential and higher polarization resistance. The enhancement in anticorrosion performance was believed to be contributed from the superhydrophobicity and dual barrier protection from the fully-covered fluoro-organosilicasol, insulating the metal from corrosive species in the medium. This superhydrophobic coating technique with good stability guaranteed better corrosion protection and also has great potential for application to other polymeric films.

Synthesis, characterization, and biocompatibility of poly (acrylic acid/methyl methacrylate)-grafted-poly (ethylene-co-tetrafluoroethylene) film for prosthetic cardiac valves

The surface of poly (ethylene-co-tetrafluoroethylene) (PETFE) strip was grafted by acrylic acid (AAc) and methyl methacrylate (MMA) onto PETFE skeleton to improve the blood compatibility and reduce thrombogenicity for prosthesis. The grafting process was carried out via γ-rays technique as initiator for addition reaction. The optimal conditions were achieved by investigating the effect of different parameters during the grafting process such as exposure to irradiation dose, comonomer concentration, comonomer composition, and solvent. The surface microstructure and composition of copoly (AAc/MMA)-grafted-PETFE surface were characterized by Fourier transform infrared spectroscopy (FTIR), CHNS/O elemental analyzer, scanning electron microscopy (SEM), and electron spectroscopy for chemical analysis (ESCA). Further, heparin was introduced onto the grafted PETFE strip surface. The blood compatibility of modified strip was investigated by the determination of platelet adhesion and thrombus formation. The results indicate that the heparinized copoly (AAc/MMA)-grafted-PETFE sample is a good candidate for manufacturing the prosthetic cardiac valves.

Al2O3-Passivated AlGaN/GaN HEMTs by Using Nonvacuum Ultrasonic Spray Pyrolysis Deposition Technique

This letter reports, for the first time, the Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -passivated AlGaN/GaN high electron mobility transistors (HEMTs) by using the nonvacuum ultrasonic spray pyrolysis deposition (USPD) technique. The Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> was devised as the surface passivation layer to effectively suppress leakage current and to reduce RF drain current collapse. The surface oxide has been characterized by using electron spectroscopy for chemical analysis, energy-dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). With respect to an unpassivated device, the Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -passivated HEMT has demonstrated superior improvements of 24.2% in maximum drain-source current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS,max</sub> ), 33.6% in maximum extrinsic transconductance (g <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m,max</sub> ), 46.8% in two-terminal breakdown voltage (BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</sub> ), and 45.3% in three-terminal off-state breakdown voltage (BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ). The corresponding improvements achieved are 9.1%, 16.1%, 61.3%, and 55.7% for I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS,max, gm,max,</sub> BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</sub> , and BV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> , respectively, as compared with passivation in Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> HEMTs. Besides, reduced interface density (Dit) and about two-order decreases in the leakage current are also achieved in the Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -MOS diode using USPD with respect to a Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -MIS diode.

Hydrophobization of silk fibroin nanofibrous membranes by fluorocarbon plasma treatment to modulate cell adhesion and proliferation behavior

Saturated fluorocarbon (CF4) immobilized silk fibroin (SF) nanofibrous membranes were prepared and characterized for biomedical applications. Biocompatible barrier membranes that provide both hydrophobic and hydrophilic surface properties on each side are critical to prohibit soft tissue invasion into localized bone defect. As a barrier membrane, SF nanofibrous mat was fabricated by electrospinning method, and then subsequently modified with water vapor treatment for insolubilization in water and CF4 gas plasma treatment for surface hydrophobization. Morphology of SF nanofibrous mats were observed by scanning electron microscopy. Conformational change of insolubilized SF nanofibers was confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and 13C nuclear magnetic resonance (NMR) spectroscopy. Immobilized fluorine atoms on CF4 plasma treated SF nanofibrous membranes were detected using electron spectroscopy for chemical analysis (ESCA). Water contact angle of the SF nanofiber membrane surface was analyzed by varying plasma input power and time. Insolubilized SF nanofibrous membrane maintained nonwoven mat structure without deformation after water immersion. SF nanofibrous membranes showed significant increment of water contact angle from 99.7° to 141.2° by CF4 gas plasma treatment. Fibroblasts on plasma untreated SF nanofibrous membranes were well attached and spread than a control tissue culture polystyrene dish. Fibroblasts on the CF4 gas plasma treated SF nanofibrous membrane showed significantly lower proliferation behavior than plasma untreated SF nanofibrous membranes. Fluorocarbon immobilized SF nanofibrous barrier membrane will be useful for biomedical applications such as a guided bone regeneration. Open image in new window

Synthesis and surface modification of polyurethanes with chitosan for antibacterial properties

Surface modification and providing antibacterial properties to the materials or devices are getting great attention especially in the last decades. In this study, polyurethane (PU) films were prepared by synthesizing them in medical purity from toluene diisocyanate and polypropylene ethylene glycol without using any other ingredients and then the film surfaces were modified by covalent immobilization of chitosan (CH) which has antibacterial activity. CH immobilized PU films (PU-CH) were found to be more hydrophilic than control PU films. Electron Spectroscopy for Chemical Analysis (ESCA) and Atomic Force Microscopy (AFM) analyses showed higher nitrogen contents and rougher surface topography for PU-CH compared to PU films. Modification with CH significantly increased antibacterial activity against Gram positive (Staphylococcus aureus) and Gram negative (Pseudomonas aeruginosa) bacteria. It was observed that the number of bacteria colonies were less about 102–105CFU/mL and number of attached viable bacteria decreased significantly after CH modification of PU films.

Effects of nurse-led case management on the self-care and health behaviors of the patients with chronic obstructive pulmonary disease in community health service

Objective To analyze the effects of nurse-led case management on the self-care and health behaviors of the patients with chronic obstructive pulmonary disease (COPD) in community health service.Methods The groups were randomly divided based on the unit of community.According to the sampling results,a total of 67 patients participated in and completed the study,including the study group with 32 patients using the nurse-led case management nursing care,and the control group with 35 patients using conventional nursing method.The self-care agency scale (ESCA) and health promoting lifestyle profile (HPLP) were used to evaluate the changes of patients' self-care and health behaviors.Results After one-year intervention,the scores of health knowledge,self-responsibihty,self-care skills and self-care in the study group were significantly higher than those scores before intervention (P ＜ 0.05).At baseline,the scores of the patients in the control group and in the study group had no significant difference (P ＞ 0.05).But after the intervention,the scores,except for the aspect of self-concept,in the study group were significantly higher than those in the control group (t =-3.49,-5.78,-11.39,-7.54,respectively; P ＜ 0.01).After one-year intervention,the total scores and the scores of each dimensions of HPLP in the study group were significantly higher than the scores in the control group (t=-2.93,-2.32,-3.07,-4.47,-9.22,-5.63,-14.53,respectively; P＜0.05).In addition,the scores in each dimension of the study group were significantly higher than the scores before the intervention (P ＜ 0.05).Conclusions The nurse-led case management can significantly promote the self-care ability and the health behaviors of the patients with COPD in community health service,so as to enhance their self-management skills.It is an effective way to implement quality community nursing. Key words: Case management; Nursing; Pulmonary diseases,chronic obstructive; Self-management

Protein Quantity on the Air–Solid Interface Determines Degradation Rates of Human Growth Hormone in Lyophilized Samples

Recombinant human growth hormone (rhGH) was lyophilized with various glass-forming stabilizers, employing cycles that incorporated various freezing and annealing procedures to manipulate glass formation kinetics, associated relaxation processes, and glass-specific surface areas (SSAs). The secondary structure in the cake was monitored by infrared and in reconstituted samples by circular dichroism. The rhGH concentrations on the surface of lyophilized powders were determined from electron spectroscopy for chemical analysis. Glass transition temperature (Tg ), SSAs, and water contents were determined immediately after lyophilization. Lyophilized samples were incubated at 323 K for 16 weeks, and the resulting extents of rhGH aggregation, oxidation, and deamidation were determined after rehydration. Water contents and Tg were independent of lyophilization process parameters. Compared with samples lyophilized after rapid freezing, rhGH in samples that had been annealed in frozen solids prior to drying, or annealed in glassy solids after secondary drying retained more native-like protein secondary structure, had a smaller fraction of the protein on the surface of the cake, and exhibited lower levels of degradation during incubation. A simple kinetic model suggested that the differences in the extent of rhGH degradation during storage in the dried state between different formulations and processing methods could largely be ascribed to the associated levels of rhGH at the solid-air interface after lyophilization.

Spectromicroscopic analysis of lithium intercalation in spinel LiMn2O4 for lithium-ion battery by 3D nano-ESCA

The process of lithium-intercalation in spinel-structured lithium manganese oxide (LiMn2O4) particles was probed by a highly spatially resolved X-ray photoelectron microscopy technique using our "3D nano-ESCA" (three-dimensional nanoscale electron spectroscopy for chemical analysis) equipment. We found the change of the line shape in Li 1s-Mn 3p core-level spectra with lithiation/delithiation of the sample. Moreover, we have succeeded in detecting the photoelectron intensity mapping of chemically lithiated/delithiated Li1±δMn2O4 crystals. It suggests the homogeneous intercalation/deintercalation from the crystal surfaces instead of the crystal edges, and the particle size dependence of the intercalation tendency.

Biodegradable poly(ester urethane) urea scaffolds for tissue engineering: Interaction with osteoblast-like MG-63 cells

Porous three-dimensional scaffolds with potential for application as cancellous bone graft substitutes were prepared from aliphatic segmented poly(ester urethane) urea using the phase-inverse technique. Proton nuclear magnetic resonance, size-exclusion chromatography, electron spectroscopy for chemical analysis, secondary ion mass spectrometry, infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, computed tomography and mechanical tests were carried out, to characterize the scaffolds’ physicochemical properties. Human osteosarcoma MG-63 cells were seeded into the scaffolds for 1, 2, 3 and 4weeks to evaluate their potential to support attachment, growth and proliferation of osteogenic cells. The scaffold–cell interaction was assessed by analysis of DNA content, total protein amount, alkaline phosphatase activity and WST-1 assay. The scaffolds supported cell attachment, growth and proliferation over the whole culture period of 4weeks (DNA, total protein amount). There was, however, a reduction in the WST-1 assay values at 4weeks, which might suggest a reduction in the rate of cell proliferation at this time.

Reduction of the pro-inflammatory response by tetrandrine-loading poly(l-lactic acid) filmsin vitroandin vivo

Inflammatory response of implantable biomaterials and drug delivery vehicles, driven by the reaction of macrophages to foreign body particles released from the implant, is an urgent problem to resolve. Despite this, little is known about the inflammatory molecular mechanism following the implantation of biomaterials and the evaluation of anti-inflammatory biomaterials. In this study, tetrandrine (TET) was loaded into poly (l-lactic acid) (PLLA) films to assess the anti-inflammatory effects in vitro and in vivo. The water contact angle measurement indicated the variation of hydrophilicity and the electron spectroscopy for chemical analysis (ESCA) data suggested that TET was loaded into PLLA films, which were marked as enriched with nitrogen atoms. TET-loading PLLA films had satisfactory sustained releasing behavior in salicylic acid solution with accelerating release. RAW 264.7 macrophages cultured in TET-loading PLLA films maintained lower levels of chemokines, cytokines, and enzymes involved in the inflammatory process, such as NO, TNF-α, IL-6, iNOS, COX-2 than control PLLA films, suggesting that TET-loading PLLA films could regulate the mRNA expression and protein expression to reduce the inflammatory response in macrophages. The degree of inflammatory reaction for the implant with the TET-loading PLLA films was significantly less severe than that close to control PLLA films in 4, 12 weeks after operation in rats. The present study will provide a new method to evaluate and treat the biocompatibility related to inflammatory response for implanted biomaterials and drug delivery system.

Analysis of fracture surface of titanium-porcelain bonding by electron spectroscopy for chemical analysis.

Three commercially available porcelains bonded to titanium were evaluated to determine the weakest zone of the titanium-porcelain bonding structures. Tensile bond tests were performed for these specimens (NO, DU, and VI) and for Ni-Cr alloy-porcelain bonding samples that served as controls. The maximum bond strengths between porcelain and titanium and the Ni-Cr alloy subjected to different metal surface treatments were compared. Sand blasting effectively increased bond strengths in titanium-porcelain bonding materials. No statistically significant differences in the maximum bond strengths were found between the NO sample and a control; however, sample NO exhibited greater maximum bond strength than DU and VI samples. The bond strengths increased with increasing area fractions of porcelain failure on fracture surfaces. The weakest zones were investigated based on the oxygen chemical states determined by electron spectroscopy for chemical analysis, which include bridging oxygen (Si-O-Si), nonbridging oxygen (Si-O(-) M(+)), and titanium oxide (O(2-)) states. We concluded that the titanium oxide layer is the weakest zone of titanium-porcelain bonding structures.

Advanced anticorrosive coatings prepared from electroactive polyimide/graphene nanocomposites with synergistic effects of redox catalytic capability and gas barrier properties

In this study, electroactive polyimide (EPI)/graphene nanocomposite (EPGN) coatings were prepared by thermal imidization and then characterized by Fourier transformation infrared (FTIR) and transmission electron microscope (TEM). The redox behavior of the as-prepared EPGN materials was identified by in situ monitoring for cyclic voltammetry (CV) studies. Demonstrating that EPGN coatings provided advanced corrosion protection of cold-rolled steel (CRS) electrodes as compared to that of neat EPI coating. The superior corrosion protection of EPGN coatings over EPI coatings on CRS electrodes could be explained by the following two reasons. First, the redox catalytic capabilities of amino-capped aniline trimer (ACAT) units existing in the EPGN may induce the formation of passive metal oxide layers on the CRS electrode, as indicated by scanning electron microscope (SEM) and electron spectroscopy for chemical analysis (ESCA) studies. More- over, the well-dispersed carboxyl-graphene nanosheets embedded in the EPGN matrix hinder gas migration exponentially. This would explain enhanced oxygen barrier properties of EPGN, as indicated by gas permeability analysis (GPA) studies.

Study on Deterioration Factors of an Electric Double-layer Capacitor

Electric double-layer capacitors (EDLCs) have the advantages of much longer life and unnecessary maintenance. However, for EDLCs used for a long period, a decrease of electrostatic capacity and an increase in internal resistance are recognized. In this study, in order to clarify the factors responsible for the deterioration of EDLCs used for a long period, chemical analysis was conducted on each component such as an activated carbon electrode and an electrolytes solution. The obtained data were compared with those from a new EDLC. The results showed that long-term use reduced electrostatic capacity about 5% and made internal resistance increase by about 1.7 times. The quantity of oxygen due to surface functional groups of the activated carbon electrode was confirmed using electron spectroscopy for chemical analysis (ESCA). As compared with results obtained from a new EDLC, long-term use made the ratio of O-C=O deriving from carboxyl group (-COOH) to C-C increase 1.2 times. The ratio of C-O deriving from hydroxyl group (-OH) to C-C also increased 1.4 times. In addition, it was found that BET surface area decreased about 40% and that pores whose diameter was in the range between 0.8 to 20 nm disappeared.

Preparation and Characterization of Fe-Au Alloy Nanoparticles for Hyperthermia Application

Water-dispersible Fe-Au alloy nanoparticles (FA_NPs) for hyperthermia application were synthesized and characterized in this study. From transmission electron microscopy examination, the mean diameter of the FA_NPs was calculated to be 3.9 ± 1.3 nm. The X-ray powder diffraction pattern of prepared FA_NPs shows 2θ peak positions corresponding to pure iron and gold. X-ray fluorescence analysis results show that the FA_NPs were composed of 36.8 wt% iron and 63.2 wt% gold, corresponding to a molecular ratio of iron to gold of 2. Electron spectroscopy for chemical analysis was used to study the binding energies of the atoms. To examine the magnetic properties, superconducting quantum interference device tests were conducted, and field-cooled and zero-field-cooled curves were obtained. The results reveal that the FA_NPs were superparamagnetic at room temperature with a saturation magnetization of 3.5 emu/g. The zeta potential was measured to be -29.8 mV for FA_NPs suspended in deionized water, which indicates good suspension. The in vitro cytotoxicity of the FA_NPs was evaluated using L929 and Hep-G2 cell lines through the WST-8 assay. No significant cytotoxic response was observed for either cell line for concentrations below 10 mg/mL after 24 h of cultivation. Hyperthermia evaluations were carried out with a 1.1-MHz high-frequency induction wave (HFIW) exposure. Each FA_NP was calculated to provide 1.33 x 10^(-16) J of heat. The viability of the Hep-G2 cell decreased under hyperthermia treatment. The FA_NPs prepared in this study have potential for hyperthermia application.

Evaluation of liquid ammonia treatment on surface characteristics of hemp fiber

In this study, we investigated the effects of liquid ammonia treatment on the surface characteristics of hemp fibers. We determined the elemental composition, morphological structure, roughness, and wettability of fiber surface using techniques such as electron spectroscopy for chemical analysis, scanning electron microscopy, atomic force microscopy, and contact angle measurements. The lignin coverage on the hemp surface was calculated from the O/C ratio and the C1 content. The results show that lignin removal from the fiber surface was significantly greater than that from the fiber bulk. After the treatment, the O/C ratio of hemp fibers increased, and cellulose was exposed. The proportion of O2 species that contributed to formation of hydrogen bonds increased; this further increased the number of hydrophilic groups in the hemp fibers, improving the fiber wettability. The liquid ammonia treatment did not change the large dislocation structures in hemp fibers, but the removal of noncellulosic materials from the fiber surface increased the roughness of the fiber surface.

Nanohybrid structure analysis and biomolecule release behavior of polysaccharide-CDHA drug carriers

Nanoscaled polymer composites were prepared from polysaccharide chitosan (CS) and Ca-deficient hydroxyapatite (CDHA). CS-CDHA nanocomposites were synthesized by in situ precipitation at pH 9, and the CS-CDHA carriers were then fabricated by ionic cross-linking methods using tripolyphosphate and chemical cross-linking methods by glutaraldehyde and genipin. Certain biomolecules such as vitamin B12, cytochrome c, and bovine serum albumin were loaded into the CS-CDHA carriers, and their release behaviors were investigated. Furthermore, these CS-CDHA carriers were examined by transmission electron microscopy, electron spectroscopy for chemical analysis, and X-ray diffraction. The release behavior of the biomolecules was controlled by the CS/CDHA ratios and cross-linked agents. By increasing the concentration of CS and the concentration of the cross-linking agents, cross-linking within carriers increases, and the release rate of the biomolecules is decreased. Moreover, the release rate of the biomolecules from the CS-CDHA carriers at pH 4 was higher than that at pH 10, displaying a pH-sensitive behavior. Therefore, these CS-CDHA hydrogel beads may be useful for intelligent drug release and accelerate bone reconstruction.