Attenuated Total Reflection Spectroscopy Research Articles

On the Nature of the Evanescent Wave

This is an unusual paper in that it does not address a particular research topic or present a novel experimental method or a new theoretical result. This paper addresses our basic understanding of the nature of the evanescent wave, the wave that is the basis of the entire field of Attenuated Total Reflection (ATR) spectroscopy. I recently had the opportunity to reexamine the foundations of ATR spectroscopy and was surprised to have had to change my own mental picture of the evanescent wave that I have built over the last 25 years. Over the years I have had numerous discussions with a large number of workers in the field as well as with my former mentor, and one of the originators and the principal developer of ATR spectroscopy, the late N.J. Harrick. Everything brought up in all these discussions was perfectly consistent with my old mental picture of the evanescent wave. Thus, I believe that the picture of the evanescent wave that I had is virtually universally held by workers in the field. This paper describes the new picture of the evanescent wave that emerged from said reexamination process.

In vitro stability study of organophosphonic self assembled monolayers (SAMs) on cobalt chromium (Co–Cr) alloy

Surface modification of cobalt chromium (Co–Cr) alloy is being investigated as a possible solution to the biomedical challenges arising from its usage. Self assembled monolayers (SAMs) of organophosphonic octadecylphosphonic acid (ODPA) were formed on the oxide surface of Co–Cr alloy by chemisorption using the solution deposition technique. High quality and well-ordered SAMs were formed which were characterized using Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle measurements and ellipsometry. The resulting monolayers were then exposed to in vitro conditions using phosphate buffered saline (PBS) solution. The samples were analyzed for a period of 1, 3, 7 and 14days. The resulting samples were characterized using XPS, AFM and Contact angle measurements. XPS atomic concentrations and detailed high energy elemental scans gave an insight into the trends of elemental concentrations over the duration of the study. SAMs were found to be strongly bound to the oxide surface after PBS exposure. AFM gave the topographic details of SAMs presence by island formation before and after SAM formation and also over the duration of the PBS exposure. Contact Angle Measurements confirmed the hydrophobicity of the surface after SAM formation and indicated a slight disorder of the SAM alkyl chain upon exposure to PBS. Thus, ODPA SAMs were successfully coated on Cobalt Chromium (Co–Cr) alloy surface and were found to be stable and strongly bound after PBS exposure.

Evaluation of polyphenylene ether ether sulfone/nanohydroxyapatite nanofiber composite as a biomaterial for hard tissue replacement.

The present work is aimed at investigating the mechanical and in vitro biological properties of polyphenylene ether ether sulfone (PPEES)/nanohydroxyapatite (nHA) composite fibers. Electrospinning was used to prepare nanofiber composite mats of PPEES/nHA with different weight percentages of the inorganic filler, nHA. The fabricated composites were characterized using Fourier transform infrared spectroscopy (FTIR)-attenuated total reflectance spectroscopy (ATR) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) techniques. The mechanical properties of the composite were studied with a tensile tester. The FTIR-ATR spectrum depicted the functional group as well as the interaction between the PPEES and nHA composite materials; in addition, the elemental groups were identified with EDX analysis. The morphology of the nanofiber composite was studied by SEM. Tensile strength analysis of the PPEES/nHA composite revealed the elastic nature of the nanofiber composite reinforced with nHA and suggested significant mechanical strength of the composite. The biomineralization studies performed using simulated body fluid with increased incubation time showed enhanced mineralization, which showed that the composites possessed high bioactivity property. Cell viability of the nanofiber composite, studied with osteoblast (MG-63) cells, was observed to be higher in the composites containing higher concentrations of nHA.Electronic supplementary materialThe online version of this article (doi:10.1186/2194-0517-2-2) contains supplementary material, which is available to authorized users.

Distance and protective barrier effects on the composite resin degree of conversion

Context:The food wrap films are used to cover the tip of curing light units in order to avoid contamination and prevent damage to the light guide. However, their effects on resin polymerization are not fully known.Aims:We investigated the effects on restoration efficiency of a food wrap protective barrier used on the tip of curing light units.Materials and Methods:For each treatment, five replications were performed, a total of 60 bovine incisor. The degree of conversion (%DC) of restorations with the composite resin Opallis EA2 was evaluated using 3 curing light devices (Optilux 501, Optilight and Ultra LED) and 2 curing distances (0 and 5 mm). The composite resin was tested for restoration of cavities in bovine crowns. %DC values were measured by the Fourier transform infrared spectroscopy-attenuated total reflectance technique.Statistical Analysis Used:The data were analyzed using 3-way ANOVA and Tukey's test.Results:Use of the protective film lowered %DC (F = 4.13; P = 0.05), and the effects of curing distance were associated to the curing light device (F = 3.61; P = 0.03).Conclusions:The distance from the light curing tip and use of a translucent protective barrier on the light-cure device can both impair composite resin %DC.

Matrix effects during monitoring of antibody and host cell proteins using attenuated total reflection spectroscopy

Production of recombinant proteins, e.g. antibodies, requires constant real-time monitoring to optimize yield and quality attributes and to respond to changing production conditions, such as host cell protein (HCP) titers. To date, this monitoring of mammalian cell culture-based processes is done using laborious and time consuming enzyme-linked immunosorbent assays (ELISA), two-dimensional sodium dodecylsulphate polyacrylamide gel electrophoresis, and chromatography-based systems. Measurements are usually performed off-line, requiring regular sample withdrawal associated with increased contamination risk. As information is obtained retrospectively, the reaction time to adapt to process changes is too long, leading to lower yield and higher costs. To address the resulting demand for continuous online-monitoring systems, we present a feasibility study using attenuated total reflection spectroscopy (ATR) to monitor mAb and HCP levels of NS0 cell culture in situ, taking matrix effects into account. Fifty-six NS0 cell culture samples were treated with polyelectrolytes for semi-selective protein precipitation. Additionally, part of the samples was subjected to filtration prior to analysis, to change the background matrix and evaluate effects on chemometric quantification models. General models to quantify HCP and mAb in both filtered and unfiltered matrix showed lower prediction accuracy compared to models designed for a specific matrix. HCP quantification in the range of 2,000-55,000 ng mL(-1) using specific models was accurate for most samples, with results within the accepted limit of an ELISA assay. In contrast, mAb prediction was less accurate, predicting mAb in the range of 0.2-1.7 g L(-1) . As some samples deviated substantially from reference values, further investigations elucidating the suitability of ATR for monitoring are required.

Formulation and delivery of improved amorphous fenofibrate solid dispersions prepared by thin film freezing

The objective of this study was to prepare amorphous fenofibrate (FB) solid dispersions using thin film freezing (TFF) and to incorporate the solid dispersions into pharmaceutically acceptable dosage forms. FB solid dispersions prepared with optimized drug/polymer ratios were characterized by modulated differential scanning calorimetry (MDSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) specific surface area measurements, Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), and supersaturation dissolution testing. Furthermore, a dry granulation technique was used to encapsulate the TFF compositions for in vitro dissolution and in vivo animal pharmacokinetic studies. The results showed that the TFF process produced amorphous, porous, microstructured, and stable solid dispersions with high surface areas. Development of solid oral dosage forms revealed that the performance of the FB containing solid dispersions was not affected by the formulation process, which was confirmed by DSC and XRD. Moreover, an in vivo pharmacokinetic study in rats revealed a significant increase in FB absorption compared to bulk FB. We confirmed that amorphous solid dispersions with large surface areas produced by the TFF process displayed superior dissolution rates and corresponding enhanced bioavailability of the poorly water-soluble drug, FB.

Selective Capture and Collection of Live Target Cells Using a Photoreactive Silicon Wafer Device Modified with Antibodies via a Photocleavable Linker

A device for the capture and recollection of live target cells is described. The platform was a silicon (Si) wafer modified with an anti-HEL antibody (anti-HEL-IgG, HEL = hen egg lysozyme) through a photocleavable 3-amino-3-(2-nitrophenyl)propionic acid (ANP) linker. The modification processes of the Si wafer surface were monitored by Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and fast-scanning atomic force microscopy (FS-AFM). The attachment of IgG and its release reaction on the Si surface via the photochemical cleavage of the ANP linker were observed directly by FS-AFM. The results of an enzyme-linked immunosorbent assay (ELISA) indicated that the photorelease of the complex of anti-HEL-IgG with the secondary antibody-alkaline phosphatase hybrid (secondary IgG-AP) from the Si surface occurs with minimum damage. Furthermore, it was possible to collect SP2/O cells selectively that express HEL on their cell membranes (SP2/O-HEL) on the Si wafer device. Photochemical cleavage of the ANP linker facilitated the effective release of living SP2/O cells whose viability was verified by staining experiments using tripan blue. Moreover, it was possible to reculture the recovered cells. This methodology represents an effective strategy for isolating intact target cells in the biological and medicinal sciences and related fields.

Protection of Wood from Microorganisms by Laccase-Catalyzed Iodination

In the present work, Norway spruce wood (Picea abies L.) was reacted with a commercial Trametes versicolor laccase in the presence of potassium iodide salt or the phenolic compounds thymol and isoeugenol to impart an antimicrobial property to the wood surface. In order to assess the efficacy of the wood treatment, a leaching of the iodinated and polymerized wood and two biotests including bacteria, a yeast, blue stain fungi, and wood decay fungi were performed. After laccase-catalyzed oxidation of the phenols, the antimicrobial effect was significantly reduced. In contrast, the enzymatic oxidation of iodide (I(-)) to iodine (I(2)) in the presence of wood led to an enhanced resistance of the wood surface against all microorganisms, even after exposure to leaching. The efficiency of the enzymatic wood iodination was comparable to that of a chemical wood preservative, VP 7/260a. The modification of the lignocellulose by the laccase-catalyzed iodination was assessed by the Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. The intensities of the selected lignin-associated bands and carbohydrate reference bands were analyzed, and the results indicated a structural change in the lignin matrix. The results suggest that the laccase-catalyzed iodination of the wood surface presents an efficient and ecofriendly method for wood protection.

Quantitative analysis of thiamine hydrochloride in tablets—Comparison of infrared attenuated total reflection, diffuse reflectance infrared and Raman spectroscopy

The application of FTIR ATR (Fourier transform infrared attenuated total reflection), DRIFT (diffuse reflectance infrared Fourier transform) and FT Raman spectroscopy for the quantification of thiamine hydrochloride, or vitamin B1, in tablets was compared. PLS (partial least squares) calibration models were built and validated using the spectra of 40 samples containing vitamin B1 and excipients. To evaluate the predictive ability of these models, the relative standard errors of prediction (RSEP) were calculated. In the case of vitamin B1 determination from the Raman data, RSEP error values of 1.5 % and 2.1 % were obtained for the calibration and validation data sets, respectively. When DRIFT spectra were applied, the respective RSEP errors were found to be 2.1 % and 2.2 %. For ATR models, these errors amounted to 3.1 % and 3.2 %, respectively. Commercial tablets containing 25mg of thiamine hydrochloride were quantified using the developed models. Derived concentrations correlated strongly with the results of the reference analysis and yielded recoveries of 99.2–100.8 %. Each of the three applied spectroscopic techniques can be employed as fast and reliable alternatives to the standard pharmacopeial methods of vitamin B1 quantification in tablets. DRIFT spectroscopy has the highest potential to become a routine technique for the quantification of solid mixtures within the pharmaceutical industry.

Preparation, characterization, and process performance of composite fibrous adsorbents as cation exchangers for high throughput and high capacity bioseparations

Fibrous materials are proposed as novel chromatographic supports depicting high throughput and high product capacity. In this work, a composite fiber harboring strong cation-exchange moieties has been investigated. Such materials were characterized by a plethora of physical methods including degree of swelling (DS), scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM), and Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR). The composite showed a high degree of grafting (∼30%) and exhibited a high swelling ratio (∼300%). Moreover, homogenous grafting and the development of an internal (functional) hydrogel were observed. The fibrous adsorbent was packed utilizing a designed “double roll” supported-structure and subsequently tested for packing efficiency and chromatography performance. The mentioned system showed similar packing efficiency of height equivalent to a theoretical plate (HETP) value and higher permeability coefficient (0.92×10−7cm2) than commercial resins. Experimentally determined Peclet number (Pe) values were within the range 60–90, suggesting a close-to-plug-flow condition. Total ionic capacity of the fibrous adsorbent was determined by the transition pH method. A capacity of 6.5mequiv./g was obtained. Moreover, a high dynamic binding capacity for lysozyme was found to be 283mg/g. On the other hand, a bed of randomly packed fiber also demonstrated high-resolution ability when a mixture of model protein was utilized to that end. Resolution was maintained at high flow rates (up to 900cm/h) and utilizing shorter gradient development routines. Direct sequestration of a model protein (lysozyme) was also possible from an artificial mixture containing 1.5% yeast homogenate. Summarizing, the composite fibrous adsorbents exhibited superior performance during early protein capture and intermediate-resolution applications.

Ion-implanted polytetrafluoroethylene enhances Saccharomyces cerevisiae biofilm formation for improved immobilization

The surface of polytetrafluoroethylene (PTFE) was modified using plasma immersion ion implantation (PIII) with the aim of improving its ability to immobilize yeast. The density of immobilized cells on PIII-treated and -untreated PTFE was compared as a function of incubation time over 24 h. Rehydrated yeast cells attached to the PIII-treated PTFE surface more rapidly, with higher density, and greater attachment strength than on the untreated surface. The immobilized yeast cells were removed mechanically or chemically with sodium hydroxide and the residues left on the surfaces were analysed with Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). The results revealed that the mechanism of cell attachment on both surfaces differs and a model is presented for each. Rapid attachment on the PIII-treated surface occurs through covalent bonds of cell wall proteins and the radicals on the treated surface. In contrast, on the untreated surface, only physisorbed molecules were found in the residue and lipids were more highly concentrated than proteins. The presence of lipids in the residue was found to be a consequence of damage to the plasma membrane during the rehydration process and the increased cell stress was also apparent by the amount of Hsp12 in the protein residue. The immobilized yeast cells on PIII-treated PTFE were found to be as active as yeast cells in suspension.

Photochemical degradation study of polyvinyl acetate paints used in artworks by Py–GC/MS

Photochemical degradation of commercial polyvinyl acetate (PVAc) homopolymer and PVAc paints mixed with burnt umber, cobalt blue, cadmium red dark, nickel azo yellow and titanium white commonly used for artworks were studied by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Py–GC/MS with single-shot technique was used for the characterization of the thermal degradation of PVAc at different temperatures, while the double-shot technique of Py–GC/MS was used to reveal the differences in the specimens before and after UV ageing, including the changes of detectable amounts of deacetylation product – acetic acid and plasticizers such as diethyl phthalate (DEP). Furthermore, the relative concentration of the pyrolysis products of the paint samples could be measured and compared in the second step of the double-shot Py–GC/MS, which are highly dependent on the presence of pigments and the ageing status of PVAc paints.

Photocrosslinkable hyaluronic acid as an internal wetting agent in model conventional and silicone hydrogel contact lenses

Photocrosslinkable methacrylated hyaluronic acid (HA) was prepared and incorporated into model conventional and silicone hydrogel contact lenses as an internal wetting agent. The molecular weight of the HA, the degree of methacrylation as well as the amount (0.25 to 1.0 wt %) incorporated were varied. The HA-containing hydrogels were analyzed using a variety of techniques including water contact angles, equilibrium water content (EWC), and lysozyme sorption. The presence of HA could be detected in the materials using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy-attenuated total reflectance. The materials containing methacrylated HA had improved hydrophilicity and reduced lysozyme sorption. Effects of modified HA on EWC were dependent upon the materials but generally increased water uptake. Increased mobility of the HA associated with a lower molecular weight and lower degree of methacrylation was found to be more effective in improving hydrophilicity and decreasing lysozyme sorption than the less mobile HA. All results found suggest that photocrosslinkable HA has significant potential in contact lens applications.

Spectroscopic investigation of the interactions between gold nanoparticles and bovine serum albumin

The interactions between bovine serum albumin (BSA) and gold nanoparticles (AuNPs), and the conformational changes of BSA induced by this interaction, were investigated by UV-visible absorption spectroscopy, fluorescence spectroscopy, and Fourier transform infrared in combination with attenuated total reflection spectroscopy (ATR-FTIR). The critical adsorption density for preventing AuNP aggregation in 0.1 mol/L phosphate buffered saline (pH 7.2) was 23 BSA molecules per gold particle or 3.8×1012 BSA molecules/cm2. BSA bound to the AuNPs with high affinity (binding constant Ks=7.59×108 L/mol), and the intrinsic fluorescence of BSA was quenched by the AuNPs in accordance with the static quenching mechanism. Both fluorescence spectroscopy and ATR-FTIR showed that AuNPs induced conformational changes in BSA, which resulted in it becoming less compact and increased the polarity of the microenvironment around the tryptophan residue Trp-212.

Preparation and characterization of electrospun polyurethane–polypyrrole nanofibers and films

AbstractPolyurethane (PU)–polypyrrole (PPy) composite films and nanofibers were successfully prepared for the purpose of combining the properties of PU and PPy. Pyrrole (Py) monomer was polymerized and dispersed uniformly throughout the PU matrix by means of oxidative polymerization with cerium(IV) [ceric ammonium nitrate Ce(IV)] in dimethylformamide. Films and nanofibers were prepared with this solution. The effects of the PPy content on the thermal, mechanical, dielectric, and morphological properties of the composites were investigated with differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR)–attenuated total reflection (ATR) spectroscopy, dielectric spectrometry, and scanning electron microscopy. The Young's modulus and glass‐transition temperatures of the composites exhibited an increasing trend with increases in the initially added amount of Py. The electrical conductivities of the composite films and nanofibers increased. The crystallinity of the composites were followed with DSC, the mechanical properties were followed with DMA, and the spectroscopic results were followed with FTIR–ATR spectroscopy. In the composite films, a new absorption band located at about 1650 cm−1 appeared, and its intensity improved with the addition of Py. The studied composites show potential for promising applications in advanced electronic devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Effect of maleic anhydride grafted polyethylene on engineering properties and morphology of fumed silica filled polyethylene blown films

Blown films of high-density polyethylene (HDPE)/fumed silica (FS) composites were prepared by melt-mixing in twin-screw extruder. Maleic anhydride grafted polyethylene (PE-g-MA) was introduced to improve the state of filler dispersion during melt processing. The blown films were tested for thermal, mechanical, morphological, barrier, and optical properties. The Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) study indicated that interaction between FS and HDPE was slightly enhanced by PE-g-MA. No change in percent crystallinity was observed but mechanical properties improved after modification. Morphological analyses showed large FS clusters at higher loading which decreased after modification. Both oxygen and water vapor transmission rates of the films increased in composites as compared to HDPE, plausibly due to formation of nanogaps in blown film and/or increased solubility of penetrant molecules at filler–matrix interface.

Real-Time Spectroscopic Analysis of Extracellular Matrix Produced by MC3T3-E1 Preosteoblastic Cells Cultured under Dynamic Conditions

The deposition of extracellular matrix (ECM) produced by osteoblasts is one of the first steps in bone formation. Composition and structure of the ECM influence the development and strength of bone, as well as the onset of its mineralization. Since ECM is secreted onto the surface where the cells attach, Fourier transform infrared (FT-IR) attenuated total reflection (ATR), as a surface sensitive technique, provides a useful tool for its investigation, as ECM instead of the cells is predominantly detected by the IR beam. The purpose of the present study was to develop the FT-IR ATR technique so that real-time measurements of the ECM produced by MC3T3-E1 osteoblasts could be obtained in situ. Measurements were performed using polarized incident IR light to apply a procedure for solvent compensation which reduces the influence of culture medium on the evaluation of the amide I and II bands. The formation of ECM took place in a flow-through chamber under dynamic conditions by applying a constant flow of culture medium and was tracked over a time period of two weeks by evaluation of the integrated absorbance of amide I and II bands reflecting the amount and isotropic arrangement of amide bonds in the ECM. Cultures without ascorbic acid had a reduced protein concentration that enabled the analysis of cell-mediated matrix accumulation. Presence and proliferation of cells after two weeks of permanent flow-through of culture medium was shown by cell counting exhibiting a 67% increase in cell number as well as by crystal violet and live/dead staining. These results demonstrate the application of FT-IR ATR spectroscopy for monitoring matrix formation.

Rehabilitation of fouled membrane from natural rubber skim latex concentration through membrane autopsy and ultrasonication enhanced membrane cleaning procedure

This study investigated the membrane foulants characteristics and cleaning protocol required for a poly vinylidene fluoride (PVDF) type, tubular cross flow 200 kD MWCO ultrafiltration membrane fouled during natural rubber skim latex concentration process. Chemical (alkaline and acidic solutions) and physical (ultrasonic application) cleaning procedures were conducted at room temperature of 28 °C and at an elevated temperature of 50 °C. The membrane permeability recoveries were obtained after the end of each membrane cleaning operation, by performing deionised water flux tests (DIWFT). The extracted chemical solutions were analyzed using total organic carbon analyzer and atomic absorption spectrophotometer to quantify organic and inorganic foulants, respectively. Fourier transformation infrared attenuated total reflection spectroscopy (ATR/FTIR) was used to examine the fouled membrane surface to determine the chemical nature of the foulants. The fouled and cleaned membrane surfaces were also examined using scanning electron microscopy (SEM). The SEM images and ATR/FTIR spectrums of fouled against cleaned membranes were used to determine the efficiencies of various cleaning procedures. The measured flux recoveries using DIWFT obtained after chemical cleaning at an elevated temperature of 50 °C were 93% and 89% with and without ultrasonic application, respectively.

Preparation and characterization of SPEEK membranes crosslinked by electron beam irradiation

Crosslinked sulfonated poly(ether ether ketone) (SPEEK) membranes were prepared by the radiation crosslinking of SPEEK with various crosslinker contents. The prepared membranes were subjected to a comparative study of proton exchange membranes (PEM) for fuel cell applications. The crosslinked SPEEK membranes were characterized by 1H nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), dynamic mechanical analysis (DMA), and Small angle X-ray scattering (SAXS). 1H NMR and FTIR-ATR confirmed the sulfonation and crosslinking of the membranes. DMA indicated that the ionic modulus and cluster T g increased with decreasing crosslinker content. This suggests that the amount of clustering in the crosslinked membrane could be reduced by increasing the crosslinker content. SAXS data showed that the crosslinker did not affect the ionic domain morphology in the membranes. The proton conductivity of all the membranes was > 10−2 S/cm. The overall findings suggest that the crosslinked SPEEK membranes offer the possibility for improving the performance of proton exchange membrane fuel cell (PEMFC), provided membranes with thermal and hydration stability.

Sorption of anionic polysaccharides by cellulose.

The sorption of anionic polysaccharides pectin, alginate, and xanthan with cellulose were investigated in presence of calcium. Calcium sorption to cellulose was limited by the carboxyl group content in fibers. Atomic Absorption Spectroscopy (AAS) analysis was used to measure the calcium in cellulose fibers and chemical oxygen demand (COD) analysis reveals that the divalent ions calcium can bind the polysaccharide onto cellulose fibers. The amount of calcium and polysaccharide bound in Ca2+/polysaccharide modified cellulose fibers was 5.8-12.5mM Ca2+/kg fibers and 1500-2400mg polysaccharide/kg fibers, respectively. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) analysis confirmed the presence of polysaccharide on calcium containing cellulose fibers. The results of alizarin dyeing experiments at the end of polysaccharide sorption further confirmed the presence of calcium in Ca2+/polysaccharide modified cellulose fibers. The basic phenomenon of interaction of soluble ionic polysaccharide and cellulosic fibers in presence of divalent cations such as calcium is a key to understand biological functions and technological applications.