Alginate-chitosan Beads Research Articles

Optimization of laccase–alginate–chitosan-based matrix toward 17 α-ethinylestradiol removal

Laccase extract (LE) from Pycnoporus sanguineus was immobilized on calcium and copper alginate–chitosan beads and applied for the removal of 17α-ethinylestradiol (EE2). Effects of immobilization conditions such as: sodium alginate (SA) concentration; LE/SA ratio and chitosan/ion (Ca+2 or Cu+2) ratio on the immobilization yield were investigated. Immobilized LE on Ca-beads and Cu-beads was then used to degrade an EE2 solution. The optimal conditions for LE immobilization on Ca-beads were: 1.5% (w/v) SA, 1:5 (v/v) LE/SA and 3:7 (v/v) chitosan/ion (Ca+2). The optimal conditions for immobilization on Cu-beads were 2.0% (w/v) SA, 0.5:5 (v/v) LE/SA and 3:7 (v/v) chitosan/ion (Cu+2). The best result was obtained for immobilized LE on Ca-beads in buffer-absent medium. Furthermore, the immobilized enzyme was reused in five cycles for EE2 removal. The formation of EE2 dimers by LE treatment has been demonstrated by electrospray ionization coupled to time of flight mass spectrometer (ESI–TOF–MS). The results evidenced that immobilized LE in alginate–chitosan–divalent cation bead is an effective alternative for EE2 removal.

Physicochemical, Nutritional, and Stability Aspects of a Meat Product (gluteus medius) Enriched with Encapsulated Fish Oil in Polyelectrolyte Beads Containing Prosopis alba Exudate Gum

This work explores the physicochemical, nutritional, and stability aspects of a meat product enriched with fish oil encapsulated in polyelectrolyte beads. Particularly, a non-conventional exudate gum obtained from Prosopis alba tree (G) was assessed as wall component of alginate-chitosan beads. Patty-type products based on beef (gluteus medius) and pork back fat (P) were nutritionally improved by adding free fish oil (P+FO), fish oil encapsulated in alginate-chitosan (P+ACh), or alginate-gum-chitosan (P+AChG) beads. In enriched raw products, the EPA+DHA content was increased 13 folds, and the n3/n6 ratio was 45–55% higher than control. During cooking, the encapsulates increased the oil retention (91 to 94%) respect to samples added with free oil (84%), and modulated the chromatic (∆E = 1.5–1.9) and textural properties (hardness was increased 10–50%; elasticity was reduced 40%) of the cooked meat products. In presence of G, polyunsaturated fatty acids retention was higher (99%) than in P+ACh (95%) or in P+FO (94%). Additionally, P+AChG showed the lowest oxidative damage (TBA value was 50% lower than P+FO) at the end of freeze storage (90 days at − 18 °C) and subsequent heat treatment (15 min at 200 °C). Present results showed that Prosopis alba exudate gum emerges as a novel and useful excipient for the development of polyelectrolyte encapsulation systems able to protect functional lipids in meat-based products.

Electrosprayed genipin cross-linked alginate-chitosan microcarriers for ex vivo expansion of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are potential therapeutic candidates, owing to their ability to differentiate into several cell types. However, the gap between availability and demand of MSCs requires alternative expansion methods from 2D culture flasks. Microcarriers are a promising approach for MSC expansion due to their high surface area-to-volume ratio. However, current commercial microcarriers do not provide the highest cell yield due to low cell attachment efficiencies and difficulty in cell detachment. This study developed a hydrogel-based microcarrier from genipin cross-linked alginate-chitosan beads. Alginate beads were produced by electrospraying before being coated with chitosan and cross-linked in genipin. The degree of cross-linking was determined through fluorescence reading of the genipin-chitosan conjugates. MSCs cultured on these microcarriers had a 26% higher cell attachment and twice the proliferation rate compared to the commercial microcarrier Cytodex 1. Cells easily detached from the hydrogel beads and did not require extended incubation periods or intense agitation during cell harvest. There was no significant difference in gene expression between the two microcarriers for the positive MSC surface markers CD-90, CD-105, and CD-73 as well as showing either low or no signal for negative MSC surface markers CD-45 and CD-34. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 122-133, 2019.

Convenient one-step approach based on stimuli-responsive sol-gel transition properties to directly build chitosan-alginate core-shell beads

Herein, chitosan-alginate core-shell gel beads are directly fabricated by a convenient one-step dripping approach. In particular, the approach exquisitely utilizes both the pH-responsive sol-gel transition property of chitosan and the calcium-responsive sol-gel transition property of alginate. The approach has a variety of benefits such as the simple method, the environmentally-friendly route (without using organic solvents and toxic reagents), the mild conditions (in aqueous solution at room temperature), and the easy post-treatment for the beads. Morphology observation from optical microscopy and scanning electron microscopy demonstrates that the resulting chitosan-alginate beads have a clear core-shell structure with a well-defined border between the core and the shell. The chitosan-alginate core-shell beads shows a good sphericity and monodispersity. Comparison experiments indicate that the shell thickness and the core state (solid or liquid) of the core-shell beads can be modulated by altering the preparation conditions (solution concentrations or pHs). Loading experiments demonstrate that the core-shell structure of the chitosan-alginate beads can be utilized to respectively load various components (e.g., fluorescent dyes, drugs, and nanoparticles) in different layers. Release studies reveal that the chitosan-alginate core-shell beads have attractive capabilities to regulate drug release through the pH-responsive sol-gel transition of the chitosan core as well as the thickness control of the alginate shell.

Chitosan-alginate immobilized lipase based catalytic constructs: Development, characterization and potential applications

In this study, lipase (LIP) was isolated from Aspergillus crevinus, statistically optimized and purified via ammonium sulfate fractionation (ASF), and Sephadex G-100 gel permeation chromatography. LIP was 2.26-folds purified with a specific activity of 223.60 U/mg. The molecular mass was estimated to be 60 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (5% stacking and a 12% resolving gel) (SDS-PAGE). The active LIP fraction was immobilized onto chitosan-alginate (CTS-ALG) beads developed in a uniform size, i.e., 2.0 ± 0.25 mm diameter using ultrasonically dispersed 2.0% (w/v) chitosan and alginate along with 0.5% (w/v) glutaraldehyde as a macromolecular crosslinking agent. Prior to exploit for detergent compatibility and dehairing purposes, various parameters including pH, thermal, Michaelis-Menten kinetic constants and influence of organic/inorganic and metal ions on PF-LIP and CST-ALG-LIPs fractions were investigated. The immobilized fractions were optimally active and stable over a broader pH (5–11) and temperature (75 °C) as compared to the free counterpart pH (7–8) and temperature (35 °C), respectively. However, the negligible difference between the KM and Vmax values of PF-LIP i.e., 0.133 ± 0.05 mg/mL and 255.0 ± 11.8 U/mL/min and CST-ALG-LIPs revealed that the conformational flexibility of LIP was retained as such. Comparative to PF-LIP, the CTS-ALG-LIPs were found much stable and retained most of their activity up to 80% in the presence of inhibitory molecules. After 75 min incubation, CTS-ALG-LIP3 retained >95% activity at pH 9.0 which was reduced to 80% at pH 10.0 and 44% at pH 11.0. Among all three samples, 100% dehairing was observed when the sheepskin was dipped for 30 min in CTS-ALG-LIP3. The dehairing of leather (sheepskin) was greatly affected by CTS-ALG-LIP3 rendering its potential candidatures for leather and tannery industry.

Improving survivability of Lactobacillus plantarum in alginate-chitosan beads reinforced by Na-tripolyphosphate dual cross-linking

In the present study, Lactobacillus plantarum PTCC 1058 was microencapsulated in Alginate-chitosan blended beads based on ionically dual cross-linking by Na-tripolyphosphate (Na-TPP). The homogenous solution of bacteria and alginate was dripped into the gelling bath of calcium chloride. After 30 min hardening, filtrate beads were transferred into the solution of chitosan. Dual cross-linked gel beads were prepared by employing Na-TPP solution to the chitosan coated beads. Morphology, particle size, alginate-chitosan interaction, characterizing the structure of single and dual cross-linked beads were determined by using scanning electron microscopy SEM, FTIR and XRD analysis. FTIR analysis demonstrated fabrication of the Na-tripolyphosphate dual cross-linked microcapsules. X-ray diffractograms revealed less amorphous nature of Ag/Cs/TPP microcapsules compared to Ag/Cs ones. Survivability of probiotics and swelling behavior of microcapsules were also evaluated under simulated gastrointestinal conditions. Based on the results, the highest viability corresponds to the dual cross-linked beads (by only 1.58 ± 0.03 log reduction) compared to single cross-linked alginate (2.26 ± 0.09 log) and chitosan-coated alginate beads (1.78 ± 0.1 log). Thus, the reinforced microcapsules could be suitable for improving the capsule stability in site-specific delivery applications.

Two kinds of ketoprofen enteric gel beads (CA and CS-SA) using biopolymer alginate

To obtain expected rapid-release and sustained-release of ketoprofen gel beads, this paper adopted biopolymer alginate to prepare alginate beads and chitosan-alginate gel beads. Formulation factors were investigated and optimized by the single factor test. The release of ketoprofen from calcium alginate gel beads in pH 1.0 hydrochloric acid solution was less than 10% during 2 h, then in pH6.8 was about 95% during 45 min, which met the requirements of rapid-release preparations. However, the drug release of chitosan-alginate gel beads in pH1.0 was less than 5% during 2 h, then in pH6.8 was about 50% during 6 h and reached more than 95% during 12 h, which had a good sustained-release behavior. In addition, the release kinetics of keteprofen from the calcium alginate gel beads fitted well with the Korsmeyer–Peppas model and followed a case-II transport mechanism. However, the release of keteprofen from the chitosan-alginate gel beads exhibited a non-Fickian mechanism and based on the mixed mechanisms of diffusion and polymer relaxation from chitosan-alginate beads. In a word, alginate gel beads of ketoprofen were instant analgesic, while chitosan-alginate gel beads could control the release of ketoprofen during gastro-intestinal tract and prolong the drug's action time.

식물추출물과 Bacillus cereus MP-310을 포함한 키토산-알긴산 복합체 비드의 항균활성

식물추출물과 Bacillus cereus MP-310을 포함한 키토산-알긴산 복합체 비드의 항균활성

Delignification of Lignocellulose Biomasses by Alginate–Chitosan Immobilized Laccase Produced from Trametes versicolor IBL-04

An extracellular laccase was produced from a lignin-degrading white-rot fungus Trametes versicolor IBL-04 using the solid-state bioprocessing of corncobs. The enzyme thus produced was effectively immobilized on alginate–chitosan beads. Immobilized laccase furnished the highest immobilization yield (81.43 ± 2.98) under optimized working conditions of 3.0% (w/v) sodium alginate concentration, 2.4% CaCl2, 0.25% chitosan concentration following an immobilization time of 5 h. The immobilization process altered the optimum pH from 5.0 to 4.0 (an acidic shift), whereas the temperature optima were displaced from 40 to 50 °C (towards higher temperature). The Michaelis–Menten constant (K m) and the maximum reaction rate (V max) of the free and immobilized laccase were 0.14 mM, and 780 µmol/mL and 0.10 mM and 814 µmol/mL, respectively. The alginate–chitosan immobilized laccase was more stable and tolerant against the activity inhibition caused by the denaturants tested, concerning its soluble laccase. Delignification results revealed that the enzyme led to a marked reduction in lignin content of all the lignocellulosic wastes with the highest delignification of 78.29% in sugarcane bagasse, followed by wheat bran and corn stover after 15 h. It is demonstrated that the immobilized laccase could be a promising option as a green catalyst for the efficient delignification of lignocellulosic biomass residues.

In vitro and in vivo evaluation of alginate and alginatechitosan beads containing metformin hydrochloride

Purpose: To prepare metformin HCl-loaded alginate (AL) and alginate-chitosan (AL-CS) beads for oral application and to evaluate their in vitro characteristics and in vivo activities.Methods: AL and AL-CS beads were prepared using ionotropic gelation. The beads were evaluated for particle size, surface morphology, drug encapsulation efficiency (EE) and in vitro drug release. The antidiabetic effects of the beads were evaluated in diabetic Sprague Dawley rats.Results: The mean particle sizes of AL and AL-CS beads in wet state ranged from 1714 ± 140 to 1850 ± 103 μm. The EE % of AL and AL-CS beads were 33.58 ± 1.56 and 24.11 ± 1.72, respectively, with sustained in vitro drug release of about 93 to 96 % within 8 days in phosphate buffer (PB). Optimized metformin HCl-loaded AL and AL-CS beads showed significant hypoglycaemic effects in diabetic rats over a prolonged period (about 12 h) after oral administration compared to the pure drug (p < 0.05).Conclusion: Metformin HCl-loaded AL and AL-CS beads for oral application may be useful in prolonging the hypoglycaemic effect of metformin. This is capable of increasing patients’ compliance to the medication.Keywords: Alginate, Beads, Chitosan, Metformin, Diabetes, In vivo study

Delignification and fruit juice clarification properties of alginate-chitosan-immobilized ligninolytic cocktail

In the present study, an in-house extracted ligninolytic enzyme cocktail from Ganoderma lucidum IBL-05 was effectively immobilized on alginate-chitosan beads using glutaraldehyde. The firm quality stable alginate-chitosan beads developed using optimum condition of 3.0: 0.5% (w/v), alginate: chitosan ratio; 1.0% (v/v) glutaraldehyde concentration and 0.5 mg/mL of protein concentration registered the maximum immobilization yield. The functional characteristics and surface morphology of the control and ligninolytic enzyme conjugated alginate-chitosan beads were characterized using Fourier-transform infrared and scanning electron microscopy, respectively. Evidently, after enzymatic treatment, a significant reduction in turbidities up to 84.02%, 57.84%, 86.14%, and 82.13% was recorded for apple, grape, orange and pomegranate juice, respectively. The enzymes were subsequently used for the delignification of various agro-industrial materials. The immobilized consortium caused the marked reduction in lignin content of all the plant residues with a maximum delignification of 57.3% in sorghum stover after 15 h. In conclusion, the study suggests the potential of the immobilized ligninolytic enzyme, as a cost-effective industrially desirable green catalyst, for biotechnological at large and industrial in particular, especially for delignification, food, and beverage applications.

Purification and immobilization of laccase from Trichoderma harzianum strain HZN10 and its application in dye decolorization.

In this study we report the purification of laccase produced by Trichoderma harzianum strain HZN10 (using wheat bran under solid state fermentation) and its application in decolorization of synthetic dyes. Extracellular laccase was purified to homogeneity by DEAE-Sepharose and Sephadex G-100 chromatography with specific activity of 162.5 U/mg and 25-fold purification. Purified laccase was immobilized in various entrapments like calcium alginate, copper alginate, calcium alginate–chitosan beads and sol–gel matrix. Optimization results revealed that the laccase immobilized in sol–gel was optimally active in wide pH range (4.0–7.0) and thermo-stable (50–70 °C) than free enzyme which was optimum at 50 °C and pH 6.0. Kinetic analysis showed Km of 0.5 mM and 2.0 mM and Vmax of 285 U/mg and 500 U/mg by free laccase and sol–gel immobilized laccase respectively with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) [ABTS] substrate. Free and immobilized laccase was employed for decolorization of three different synthetic dyes (malachite green, methylene blue and congo red). High performance liquid chromatography (HPLC) analysis results revealed that approximately 100% of malachite green, 90% of methylene blue and 60% of congo red dyes at initial concentration of 200 mg/L were decolorized within 16, 18 and 20 h, respectively by laccase immobilized in sol–gel matrix in the presence of 1-hydroxybenzotriazole (HBT) mediator. During the decolorization all three synthetic dyes showed various peaks on HPLC chromatogram indicating different by-products formation. Finally, phytotoxicity analysis results revealed that the by-products of synthetic dyes (formed during decolorization) showed less toxicity against Phaseolus mungo compared to untreated synthetic dyes.

Validated HPLC method for the pharmacokinetic study of oral extended-release cefpodoxime proxetil chitosan–alginate beads in rabbits

The aim of this study is to develop a simple and applicable HPLC method for the detection of cefpodoxime acid (CFA) in rabbit plasma after oral administration of cefpodoxime proxetil (CFP) loaded chitosan–alginate (CH-ALG) beads formulation. CFP is a prodrug that is deesterified in vivo to its active metabolite CFA to exhibit antibiotic activity. Chromatographic separation of CFA and internal standard (IS) was achieved by a RP18(C18), Phenomenax®100, (250×4.6mm) with the mobile phase consisting of (0.02mol/l (20mM) ammonium acetate solution and acetonitrile (92:8, v/v, pH=4.6) at a flow rate of 1.0ml/min. The method was validated according to the requirements of US-FDA guidelines for bioanalytical method validation. The linear regression analysis for the calibration plots showed good linear relationship (R2=0.9905) in the working concentration range of 0.5–50μg/ml. The limits of detection and quantification (S/N=3) were 0.069 and 0.136μg/ml. Plasma CFA levels were successfully determined in rabbit with satisfactory precision and accuracy. The analyte was found to be stable after a number of stability studies. The proposed HPLC method was successfully applied to pharmacokinetic study in rabbits for CFP loaded CH-ALG beads and marketed immediate release (IR) tablets. All pharmacokinetic parameters were assessed.

Constructing "quantized quorums" to guide emergent phenotypes through quorum quenching capsules.

Microbial cells have for many years been engineered to facilitate efficient production of biologics, chemicals, and other compounds. As the "metabolic" burden of synthetic genetic components can impair cell performance, microbial consortia are being developed to piece together specialized subpopulations that collectively produce desired products. Their use, however, has been limited by the inability to control their composition and function. One approach to leverage advantages of the division of labor within consortia is to link microbial subpopulations together through quorum sensing (QS) molecules. Previously, we directed the assembly of "quantized quorums," microbial subpopulations that are parsed through QS activation, by the exogenous addition of QS signal molecules to QS synthase mutants. In this work, we develop a more facile and general platform for creating "quantized quorums." Moreover, the methodology is not restricted to QS-mutant populations. We constructed quorum quenching capsules that partition QS-mediated phenotypes into discrete subpopulations. This compartmentalization guides QS subpopulations in a dose-dependent manner, parsing cell populations into activated or deactivated groups. The capsular "devices" consist of polyelectrolyte alginate-chitosan beads that encapsulate high-efficiency (HE) "controller cells" that, in turn, provide rapid uptake of the QS signal molecule AI-2 from culture fluids. In this methodology, instead of adding AI-2 to parse QS-mutants into subpopulations, we engineered cells to encapsulate them into compartments, and they serve to deplete AI-2 from wild-type populations. These encapsulated bacteria therefore, provide orthogonal control of population composition while allowing only minimal interaction with the product-producing cell population or consortia. We envision that compartmentalized control of QS should have applications in both metabolic engineering and human disease. Biotechnol. Bioeng. 2017;114: 407-415. © 2016 Wiley Periodicals, Inc.

친환경농자재 개발을 위한 알긴산-키토산비드 제조 및 응용

친환경농자재 개발을 위한 알긴산-키토산비드 제조 및 응용

Encapsulation of protease from Aspergillus oryzae and lipase from Thermomyces lanuginoseus using alginate and different copolymer types

Although the application of enzymes in food as a food processing aid and enzyme supplement is of interest and widely used, the enzymes can be easily deactivated or lose their activity due to many causes such as pH and moisture as well as through the introduction of incompatible ingredients during food processing and storage. These problems can be solved by the encapsulation technique, especially in a gel matrix. The influences were studied of the alginate concentration, types of copolymer and their concentrations on the bead size, encapsulation yield (EY), encapsulation efficiency (EE), leakage and the retention of enzyme activity during storage period of encapsulated protease from Aspergillus oryzae and lipase from Thermomyces lanuginosus beads. A solution of purified protease or lipase was encapsulated in calcium alginate-chitosan beads (CACB), calcium alginate-xanthan gum beads (CAXB) and calcium alginate-maltodextrin beads (CAMB) using the extrusion method. Increasing the alginate and copolymer concentrations in the solution increased the bead size, EY, EE and the retention of enzyme activity during the storage period and reduced leakage of both the encapsulated protease and lipase. In addition, different types of copolymer significantly (p ≤ 0.05) affected these properties of both encapsulated enzymes. Furthermore, protease encapsulated using 2.0% alginate and 0.2% chitosan provided the highest EY (81.7%) and EE (77.2%) with a bead size of 1.85 mm and 8.1% leakage. The retention of encapsulated protease activity and the shelf-life of encapsulated enzyme which was expressed as half-life, the time required for the enzyme activity to decrease by half (thalf life) were 75.8% and 27.2 wk, respectively after storage at 4 °C for 10 wk. For lipase, encapsulation using 2.0% alginate and 0.4% xanthan gum provided the highest EY (42.5%) and EE (43.9%) and the bead size and leakage were 1.81 mm and 6.2%, respectively. The retention of encapsulated lipase activity and the thalf life were 77.9% and 27.8 wk, respectively after storage at 4 °C for 10 wk. CACB was a suitable complex polymer for encapsulating protease while CAXB was suitable for lipase. EY and EE values of CACB-protease were higher than those of CAXB-lipase. Therefore, the encapsulation method, gelling conditions and interactions between carriers and lipase should be further studied.

Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase.

In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as adjuvant in the therapy of familial polyposis. The systems were prepared by ionotropic gelation using needles with different diameters (400 and 600 μm). Morphology, particle size, swelling behavior, and in vitro drug release performance of the beads in aqueous media with different pH were investigated. The experimental results demonstrated that the presence of chitosan in the formulation caused an increase of the mechanical resistance of the bead structure and, as a consequence, a limitation of the bead swelling ability and a decrease of the drug release rate at neutral pH. Alginate-chitosan beads could be a good tool to guarantee a celecoxib colon delivery.

Natural Polymer Based Mucoadhesive Hydrogel Beads of Nizatidine: Preparation, Characterization and Evaluation.

Background: Dosage forms which precisely control the release rates and targets drugs to a specific body site have made enormous impact in the formulation and development of novel drug delivery systems. Methods: A prolonged release mucoadhesive hydrogel system of nizatidine was prepared by ionotropic gelation and polyelectrolyte complexation technique using natural, biodegradable polymers with or without chitosan. Prepared formulations were subjected to in vitro evaluation and several characterization studies. Results: Formulations with chitosan showed good drug content, swelling index and mucoadhesive strength when compared to batches containing alginate alone. The drug in formulations found to be intact and compatible with polymers used and surface morphology of prepared beads were found satisfactory. Two optimized formulations containing alginatechitosan shows Higuchi model and perfect zero order release. All the formulations with copolymer showed better sustained the drug release when compared with formulations without chitosan. Conclusion: Alginate-chitosan beads prepared by ionotropic geltion and polyelectrolyte complexation method found to be better than ionically cross linked alginate beads alone. Therefore, dual cross-linked beads are promising carrier for oral control release.

Prosopis alba exudate gum as excipient for improving fish oil stability in alginate–chitosan beads

The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate–chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate–chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate–chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect.

Chitosan enriched three-dimensional matrix reduces inflammatory and catabolic mediators production by human chondrocytes.

This in vitro study investigated the metabolism of human osteoarthritic (OA) chondrocytes encapsulated in a spherical matrix enriched of chitosan. Human OA chondrocytes were encapsulated and cultured for 28 days either in chitosan-alginate beads or in alginate beads. The beads were formed by slowly passing dropwise either the chitosan 0.6%–alginate 1.2% or the alginate 1.2% solution through a syringe into a 102 mM CaCl2 solution. Beads were analyzed histologically after 28 days. Interleukin (IL)-6 and -8, prostaglandin (PG) E2, matrix metalloproteinases (MMPs), hyaluronan and aggrecan were quantified directly in the culture supernatant by specific ELISA and nitric oxide (NO) by using a colorimetric method based on the Griess reaction. Hematoxylin and eosin staining showed that chitosan was homogeneously distributed through the matrix and was in direct contact with chondrocytes. The production of IL-6, IL-8 and MMP-3 by chondrocytes significantly decreased in chitosan-alginate beads compared to alginate beads. PGE2 and NO decreased also significantly but only during the first three days of culture. Hyaluronan and aggrecan production tended to increase in chitosan-alginate beads after 28 days of culture. Chitosan-alginate beads reduced the production of inflammatory and catabolic mediators by OA chondrocytes and tended to stimulate the synthesis of cartilage matrix components. These particular effects indicate that chitosan-alginate beads are an interesting scaffold for chondrocytes encapsulation before transplantation to repair cartilage defects.