Characterization of bioscoured cotton fabrics using FT-IR ATR spectroscopy and microscopy techniques

The effects of bioscouring were investigated by characterizing the chemical and physical surface changes of cotton fabrics using a purified pectinase enzyme from Bacillus subtilis strain WSHB04-02. Fourier-transform infrared (FT-IR) attenuated total-reflectance (ATR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques were employed. FT-IR ATR spectroscopy provided a fast and semi-quantitative assessment of the removal of pectins and/or waxes on the cotton surface by comparing the changes in intensity of the carbonyl peak induced by HCl vapor treatment at around 1736 cm(-1). The bioscoured surface could be clearly distinguished from those of untreated and alkali-treated cotton fibers using a combination of SEM and AFM. The images produced using these techniques revealed that the surface morphography and topography of the cotton fibers were shaped by the etching action mode of pectinases during bioscouring. These findings demonstrated that AFM is a useful supplement to SEM in characterizing cotton surfaces.     

Differential expression of prokineticin receptors by endothelial cells derived from different vascular beds: a physiological basis for distinct endothelial function.

Prokineticins (PKs), multifunctional secreted proteins, activate two endogenous G protein-coupled receptors (R) termed PK-R1 and PK-R2. It was suggested that PK1 acts selectively on the endothelium of endocrine glands, yet PK-Rs were also found in endothelial cells (EC) derived from other tissues. Therefore we examined here the characteristics of PK - system in EC derived from different vascular beds. Corpus luteum (CL)-derived EC (LEC) expressed both PK-R1 and PK-R2. In contrast, EC from the aorta (BAEC) only expressed PK-R1. Interestingly, also EC from brain capillaries (BCEC) expressed only PK-R1. The distinct pattern of PK-R expression may define EC phenotypic heterogeneity. Regulation of receptor expression also differed in BAEC and LEC: TNFalpha markedly reduced PK-R1 only in BAEC, but serum removal decreased PK-R1 in both cell types. Therefore, if cells were initially serum-starved, the anti-apoptotic effect of PKs was retained only in LEC. Yet, addition of PKs concomitant with serum removal enhanced the proliferation and survival of both BAEC and LEC. Immunohistochemical staining showed that in CL and aorta PK1 was expressed in smooth muscle cells in vessel walls, suggesting a paracrine mode of action. PK1 enhanced the net paracellular transport (measured by electrical resistance and Mannitol transport) in LEC but not in BAEC or BCEC. Collectively, these findings indicate that PKs serve as mitogens and survival factors for microvascular (LEC) and macrovascular (BAEC) EC. However, the distinct expression and function of PK receptors suggest different physiological roles for these receptors in various EC types.     

Surface composition and morphology of starch,amylose, and amylopectin films

The surfaces of solution-cast films of starch, amylose, and amylopectin were examined with scanning electron microscopy (SEM), atomic force microscopy (AFM), electron spectroscopy for chemical analysis (ESCA), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The surface topography visualized by SEM showed that amylopectin films were very smooth whereas amylose and starch films were rougher. It appears that crystallinity or phase separation in the bulk of the film affects the surface topography. AFM showed that the outmost surfaces of all films were covered with small protrusions, 15-35 nm wide and 1-4 nm high. Studies with ESCA revealed the presence of 3-8% nitrogen on the surfaces. ToF-SIMS indicated that the nitrogen originates from protein because ionic fragments from amino acids and the peptide backbone were found. Extracts from the top surface layer of the starch film showed protein bands in gel electrophoresis (SDS-PAGE) around 60 kDa, which is in the same molecular weight range as the biosynthesizing enzyme GBSS I present in starch granules. The proteins apparently phase separated during film formation and migrated to the surface, resulting in an extensive enrichment of proteins in the film surface, where about 8% of the protein is present in the top 0.01% of the film. We believe that the protrusions observed with AFM could be one or a few proteins aggregated side by side.     

黄曲霉毒素氧化酶/壳聚糖-单壁碳纳米管/聚邻苯二胺修饰电极对杂色曲霉素的检测

将黄曲霉毒素氧化酶(AFO)固定在壳聚糖(CS)-单壁碳纳米管(SWCNTs)杂交膜中,组装在聚邻苯二胺(POPD)修饰的金电极(Au)表面,制备了对杂色曲霉素(ST)敏感的生物传感器(AFO/CS-SWCNTs/POPD/Au)。运用原子力显微镜(AFM)、傅立叶变换红外光谱(FT-IR)和交流阻抗技术(EIS)对电极组装过程进行了表征。循环伏安法研究表明,AFO在修饰电极上发生了准可逆的氧化还原反应,是表面控制过程,其式量电位为-0.436V(vs.Ag/AgCl),说明包埋在CS-SWCNTs中的AFO和电极之间发生了直接电子传递。AFO修饰电极对ST具有明显的电催化作用,其表观米氏常数appKM为7.13μmol/L,催化电流与ST浓度在10～310ng/mL范围内呈线性关系,相关系数为0.997,检出限为3ng/mL(S/N=3),响应时间小于10s。组装的生物传感器具有较好的稳定性与重现性,连续检测20ng/mL的ST标准溶液11次,电流值RSD为3.9%;放置一个月后,其电流响应值仍为初始值的85.6%。该方法具有较高的选择性和灵敏度,应用于实际样品检测时,其回收率在87.6%～105.5%之间...     

Zinc supplementation decreases hepatic copper accumulation in LEC rat

The effect of dietary zinc (Zn) supplementation on copper (Cu)-induced liver damage was investigated in Long-Evans Cinnamon rats (LEC), a model for Wilson's disease (WD). Four-week-old LEC (N=64) and control Long-Evans (LE) (N=32) female rats were divided into two groups; one group was fed with a Zn-supplemented diet (group I) and the other was given a normal rodent diet (group II). LEC rats were killed at 6, 8, 10, 12, 18, and 20 wk of age; the LE control rats were killed at 6, 12, 18, and 20 wk of age. Cu concentration in the liver was reduced in LEC rats fed the Zn-supplemented diet compared with LEC rats on the normal diet between 6 and 18 wk of age. Metallothionein (MT) concentration in the livers of LEC rats in group I increased between 12 and 20 wk of age, whereas hepatic MT concentration in LEC rats from group II decreased after 12 wk. Hepatocyte apoptosis, as determined by TUNEL, was reduced in Zn-supplemented LEC rats at all ages. Cholangiocellular carcinoma was observed only in LEC rats in group II at wk 20. These results suggest that Zn supplementation can reduce hepatic Cu concentration and delay the onset of clinical and pathological changes of Cu toxicity in LEC rats. Although the actual mechanism of protection is unknown, it could be explained by sequestration of dietary Cu by intestinal MT, induced by high dietary Zn content.     

Yeast cell adhesion on oligopeptide modified surfaces

Self-assembling oligopeptides are novel materials with potential bioengineering applications; this paper explores the use of one of these oligopeptides, EAK 16 II, for modifying the surface properties of cell-supporting substrates. To characterize the surface properties, thermodynamic measurements of liquid contact angle and surface free energy were correlated to atomic force microscopy (AFM) observations. A critical concentration of 0.1 mg/ml was found necessary to completely modify the surface properties of the substrate with EAK 16 II. Adhesion of a yeast cell, Candida utilis, was modified by the coating of EAK 16 II on both hydrophobic (plastic) and hydrophilic (glass) surfaces: Cell coverage was slightly enhanced on the glass substrate, but decreased significantly on the plastic substrate. This indicates that the yeast cell adhesion was mainly determined via hydrophobic interactions between the substrate and the cell wall. However, on the EAK 16 II modified glass substrate, surface roughness might be a factor in causing a slightly larger cell adhesion than that on bare glass. The morphology of adhered cells was also obtained with AFM imaging, showing a depression at the center of the cell on all substrates. Small depressions on the oligopeptide-coated surfaces and plastic substrate may indicate good water-retaining ability by the cell. There was no apparent difference in cell adhesion and morphology among cells obtained from lag, exponential and stationary growth phases.     

Preparation and characterization of novel nanocomposite films formed from silk fibroin and nano-TiO2

This paper describes the synthesis and characterization of new regenerated silk fibroin (SF)/nano-TiO(2) composite films. The preparation method, based on the sol-gel technique using butyl titanate as oxide precursor, could avoid reagglomeration of the prepared nanoparticles. Samples were characterized mainly by X-ray diffraction (XRD), ultra-violet (UV) spectroscopy, atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The UV and AFM results indicated that TiO(2) nanoparticles could be well dispersed inside the SF film, and the size of TiO(2) was about 80nm. The XRD and FT-IR analysis implied that the formation of nano-TiO(2) particles may induce the conformational transition of silk fibroin to a typical Silk II structure partly with the increasing of crystallinity in the composite films. Compared to the pure SF films, the mechanical and thermal properties of composite films were improved, and the solubility in water was decreased due to the conformational transition of silk fibroin to Silk II structure.     

Polymer microarrays for high throughput discovery of biomaterials

The discovery of novel biomaterials that are optimized for a specific biological application is readily achieved using polymer microarrays, which allows a combinatorial library of materials to be screened in a parallel, high throughput format (1). Herein is described the formation and characterization of a polymer microarray using an on-chip photopolymerization technique (2). This involves mixing monomers at varied ratios to produce a library of monomer solutions, transferring the solution to a glass slide format using a robotic printing device and curing with UV irradiation. This format is readily amenable to many biological assays, including stem cell attachment and proliferation, cell sorting and low bacterial adhesion, allowing the ready identification of 'hit' materials that fulfill a specific biological criterion (3-5). Furthermore, the use of high throughput surface characterization (HTSC) allows the biological performance to be correlated with physio-chemical properties, hence elucidating the biological-material interaction (6). HTSC makes use of water contact angle (WCA) measurements, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). In particular, ToF-SIMS provides a chemically rich analysis of the sample that can be used to correlate the cell response with a molecular moiety. In some cases, the biological performance can be predicted from the ToF-SIMS spectra, demonstrating the chemical dependence of a biological-material interaction, and informing the development of hit materials (5,3).     

Formation of oriented polypeptides on Au(111) surface depends on the secondary structure controlled by peptide length.

We synthesized three different lengths of poly(L-lysine) containing an -SH group at the terminal (PLL(n)-SH, n (polymerization degree) = 4, 10, 30) and adsorbed them on an Au(111) surface. To analyze the formation process and the structure of self-assembled monolayers (SAMs), we used atomic force microscopy (AFM) and Fourier transform infrared reflection absorption spectra (FT-IR RAS). At the initial stage of SAM growth, formation of nanosize domains was confirmed by AFM imaging. The alpha-helical PLL(30)-SH exhibited a well-defined SAM structure after adsorption reached equilibrium. The alpha-helical PLL(30)-SH was almost perpendicular to the gold surface and exhibited interesting molecular packing due to the secondary structure of PLL(30)-SH and the underlying Au(111) array. The tilt angle of the helix axis from the substrate normal was estimated to be about 50 degrees (AFM) and 44 degrees (FT-IR RAS) respectively. On the other hand, PLL(4)-SH and PLL(10)-SH formed beta-sheet-type SAMs on the Au(111) surface based on the structure determined by FT-IR RAS spectrum.     

<Emphasis Type="Italic">Escherichia coli,Pseudomonas aeruginosa</Emphasis>, and<Emphasis Type="Italic"> Staphylococcus aureus</Emphasis> Attachment Patterns on Glass Surfaces with Nanoscale Roughness

Attachment tendencies of Escherichia coli K12, Pseudomonas aeruginosa ATCC 9027, and Staphylococcus aureus CIP 68.5 onto glass surfaces of different degrees of nanometer-scale roughness have been studied. Contact-angle and surface-charge measurements, atomic force microscopy (AFM), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM) were employed to characterize substrata and bacterial surfaces. Modification of the glass surface resulted in nanometer-scale changes in the surface topography, whereas the physicochemical characteristics of the surfaces remained almost constant. AFM analysis indicated that the overall surface roughness parameters were reduced by 60–70%. SEM, CLSM, and AFM analysis clearly demonstrates that although E. coli, P. aeruginosa and S. aureus present significantly different patterns of attachment, all of the species exhibited a greater propensity for adhesion to the “nano-smooth” surface. The bacteria responded to the surface modification with a remarkable change in cellular metabolic activity, as shown by the characteristic cell morphologies, production of extracellular polymeric substances, and an increase in the number of bacterial cells undergoing attachment.     

Effect of glutathione depletion on removal of copper from LEC rat livers by tetrathiomolybdate

Tetrathiomolybdate (TTM) is a powerful and selective copper (Cu) chelator that is used as a therapeutic agent for Wilson disease. TTM is the sole agent that can remove Cu bound to metallothionein (MT) in the livers of Long-Evans rats with a cinnamon-like coat color (LEC rats). However, the administration of excess TTM causes the deposition of Cu and molybdenum (Mo) in the liver. In the present study, the effect of hepatic glutathione (GSH) depletion on the removal of Cu from the livers of LEC rats was evaluated to establish an effective therapy by TTM. Pretreatment with l-buthionine sulfoximine (BSO), a depletor of GSH in vivo, reduced the amounts of Cu and Mo excreted into both the bile and the bloodstream, and increased the amounts of Cu and Mo deposited in the livers of LEC rats in the form of an insoluble complex 4 h after the TTM injection. The results suggest that GSH depletion creates an oxidative environment in the livers of LEC rats, and the oxidative environment facilitates the insolubilization of Cu and Mo in the livers of LEC rats after the TTM injection. Therefore, the effect of TTM on the removal of Cu from the liver was reduced in the oxidized condition. Wilson disease patients and LEC rats develop liver injury caused by oxidative damage. From a clinical viewpoint, increasing in the GSH concentration is expected to enhance the effect of TTM.     

Effect of SDS on human hair: Study on the molecular structure and morphology

This paper presents a model study to understand the effect of surfactants on the physicochemical properties of human hair. FT‐IR ATR spectroscopy has been employed to understand the chemical changes induced by sodium dodecyl sulfate (SDS) on human scalp hair. In particular, the SDS induced changes in the secondary structure of protein present in the outer protective layer of hair, i.e. cuticle, have been investigated. Conformational changes in the secondary structure of protein were studied by curve fitting of the amide I band after every phase of SDS treatment. It has been found that SDS brings rearrangements in the protein backbone conformations by transforming β ‐sheet structure to random coil and β ‐turn. Additionally, AFM and SEM studies were carried out to understand the morphological changes induced on the hair surface. SEM and AFM images demonstrated the rupture and partial erosion of cuticle sublayers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Unusual accumulation of copper related to induction of metallothionein in the liver of LEC rats.

Copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) levels in organs of LEC rats (Long-Evans rats with a cinnamon-like coat color), which develop spontaneous jaundice with hereditary hepatitis, were determined by instrumental neutron activation analysis method. Unusual accumulations of Cu in the liver of LEC rats were found, depending on the age of the animals, the metal concentration being more than approximately 20-40 times those of normal LEA rats (Long-Evans rats with an agouti coat color). Fe and Zn were also accumulated, in addition to Cu, significantly in the LEC rats. The unusual Cu accumulations in the liver of LEC rats were associated with the induction of metallothionein, estimated by radioimmunoassay method, in the liver of LEC rats, rather than that of superoxide dismutase, estimated by electron spin resonance -spin trapping method. These findings suggest that the unusual Cu accumulation in LEC rats is involved in the development of jaundice, hepatic injury and hepatocellular carcinoma.     

Structural and optical properties of Cu‐doped ZnS nanoparticles formed in chitosan/sodium alginate multilayer films

Chitosan/alginate multilayers were fabricated using a spin‐coating method, and ZnS:Cu nanoparticles were generated within the network of two natural polysaccharides, chitosan and sodium alginate. The synthesized nanoparticles were characterized using an X‐ray diffractometer (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). The results showed that cubic zinc blende‐structured ZnS:Cu nanoparticles with an average crystal size of ~ 3 nm were uniformly distributed. UV–vis spectra indicate a large quantum size effect and the absorption edge for the ZnS:Cu nanoparticles slightly shifted to longer wavelengths with increasing Cu ion concentrations. The photoluminescence of the Cu‐doped ZnS nanoparticles reached a maximum at a 1% doping level. The ZnS:Cu nanoparticles form and are distributed uniformly in the composite multilayer films with a surface average height of 25 nm. Copyright © 2013 John Wiley & Sons, Ltd.     

Metal ions differentially influence the aggregation and deposition of Alzheimer's beta-amyloid on a solid template

The abnormal deposition and aggregation of beta-amyloid (Abeta) on brain tissues are considered to be one of the characteristic neuropathological features of Alzheimer's disease (AD). Environmental conditions such as metal ions, pH, and cell membranes are associated with Abeta deposition and plaque formation. According to the amyloid cascade hypothesis of AD, the deposition of Abeta42 oligomers as diffuse plaques in vivo is an important earliest event, leading to the formation of fibrillar amyloid plaques by the further accumulation of soluble Abeta under certain environmental conditions. In order to characterize the effect of metal ions on amyloid deposition and plaque growth on a solid surface, we prepared a synthetic template by immobilizing Abeta oligomers onto a N-hydroxysuccinimide ester-activated solid surface. According to our study using ex situ atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), and thioflavin T (ThT) fluorescence spectroscopy, Cu2+ and Zn2+ ions accelerated both Abeta40 and Abeta42 deposition but resulted only in the formation of "amorphous" aggregates. In contrast, Fe3+ induced the deposition of "fibrillar" amyloid plaques at neutral pH. Under mildly acidic environments, the formation of fibrillar amyloid plaques was not induced by any metal ion tested in this work. Using secondary ion mass spectroscopy (SIMS) analysis, we found that binding Cu ions to Abeta deposits on a solid template occurred by the possible reduction of Cu ions during the interaction of Abeta with Cu2+. Our results may provide insights into the role of metal ions on the formation of fibrillar or amorphous amyloid plaques in AD.     

A self-assembled monolayer-based micropatterned array for controlling cell adhesion and protein adsorption

We developed a surface micropatterning technique to control the cell adhesion and protein adsorption. This micropatterned array system was fabricated by a photolithography technique and self-assembled monolayer (SAM) deposition. It was hypothesized that the wettability and functional terminal group would regulate cell adhesion and protein adsorption. To demonstrate this hypothesis, glass-based micropatterned arrays with various functional terminal groups, such as amine (NH(2)) group (3-aminopropyl-triethoxysilane, APT), methyl (CH(3)) group (trichlorovinylsilane, TVS), and fluorocarbon (CF(3)) group (trichloro(1H, 1H, 2H, 2H-perfluorooctyl)silane, FOTS), were used. The contact angle was measured to determine the hydrophilic and hydrophobic properties of materials, demonstrating that TVS and FOTS were hydrophobic, whereas APTs were relatively hydrophilic. The cell adhesion was significantly affected by the wettability, showing that the cells were not adhered to hydrophobic surfaces, such as TVS and FOTS. Thus, the cells were selectively adhered to glass substrates within TVS- and FOTS-based micropatterned arrays. However, the cells were randomly adhered to APTs-based micropatterned arrays due to hydrophilic property of APTs. Furthermore, the protein adsorption of the SAM-based micropatterned array was analyzed, showing that the protein was more absorbed to the TVS surface. The surface functional terminal group enabled the control of protein adsorption. Therefore, this SAM-based micropatterned array system enabled the control of cell adhesion and protein adsorption and could be a potentially powerful tool for regulating the cell-cell interactions in a well-defined microenvironment.     

New insights into red cell network structure, elasticity, and spectrin unfolding--a current review

The red cell membrane's well-recognized ability to withstand the stresses of circulation clearly has its origins in various levels of spectrin-actin network structure. We highlight recently obtained insights into this sub-structure and also briefly explain the implications to membrane components that interact with the network. Novel insights into the resilience of this cytoskeleton are being provided by experiments that range from atomic force microscopy (AFM) tests of single, unfoldable spectrin chains to micropatterned photobleaching of a pipette-deformed network. Continued progress in atomic level structure determinations of non-erythroid spectrin and related repeats are further complemented by theoretical efforts--computational approaches most notably--that have begun to correlate molecular scale aspects of structure with micro-mechanical measures. All of this recent activity in the biophysics of red cell structure-function challenges and refines some of the most basic tenets in cell membrane response.     

A scanning near-field optical microscope approach to biomolecule patterning

In view of future generations of biosensors and advanced biomaterials, photochemistry in the near field using scanning near-field optical microscopy is investigated. The potential of direct near-field-induced photoactivation is demonstrated on standard photoresist. Photoimmobilization of maleimidoaryldiazirine on silicon substrates and bovine serum albumin on glass substrates is achieved, opening the way to a controlled biopatterning of surfaces with submicrometer feature size. The obtained patterns are characterized using atomic force microscopy, time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and near-field fluorescence microscopy.     

Characterization of cotton fabric scouring by FT-IR ATR spectroscopy

FT-IR attenuated total reflectance (ATR) spectroscopy has been used for the fast characterization of cotton fabric scouring process. The greige and the scoured cotton fabrics showed very similar FT-IR spectrum in transmission mode because the bulk composition of the fabrics are similar. However, FT-IR ATR spectroscopy can provide information about the surface of a fabric. By examination of C–H stretching region at 2800–3000 cm⁻¹, the amount of waxes left on the fabric can be estimated. The presence of pectins and/or waxes can also be probed by observation of carbonyl peak induced by the HCl vapor treatment on the fabric. Based on these changes of FT-IR ATR spectra, the scouring process has been characterized.     

Analysis of recombinant protein expression using localized surface plasmon resonance (LSPR)

The localized surface plasmon resonance (LSPR)-based optical biosensor using nano-structures of noble metals has been considered as a useful tool for label-free detection of DNA hybridization and protein-protein interactions. We fabricated LSPR-based optical biosensors using gold nano-islands (nominal thickness; 75 A) on glass substrates that were easily made using the conventional fabrication methods. The formation of gold nano-islands on glass substrates was realized by heat treatment of thin gold film deposited with a low deposition rate (approximately 0.05 A/s). The morphologies of sensor surfaces composed of gold nano-islands were observed using an atomic force microscope (AFM) with a non-contact mode. To investigate the sensing capacity of the gold nano-island sensor for the binding of proteins by affinity interactions, the streptavidin and biotin interaction was used as a model system. In addition, detection of recombinant glutathione-S-transferase (GST)-tagged human interleukin-6 (hIL6) expressed in Escherichia coli was carried out by LSPR. It is expected that the LSPR sensors composed of gold nano-islands can be an alternative to traditional methods such as SDS-polyacrylamide gel electrophoresis (SDS-PAGE) for fast analysis of protein expression.