Biomedical subjects

G Ciardelli

Publications and source records attributed to G Ciardelli.

11 recordsLinked to original sources

PubMed2006

Transglutaminase reactivity with gelatine: perspective applications in tissue engineering.

Gelatine was crosslinked by means of an enzymatic treatment using tissue transglutaminase (tTGase) (Sigma) and microbial transglutaminase (mTGase) (Ajinomoto) which catalyses the formation of isopeptide bonds between the gamma-carbonyl group of a glutamine residue and the epsilon-amino group of a lysine residue. The reaction is an interesting alternative to the traditional glutaraldehyde crosslinking, which has several drawbacks (e.g., in medical application) due to the toxicity of the chemical reagent. To further investigate the possibility to utilize the modified protein for tissue engineering application, TGase crosslinked gelatine was incorporated in a gellan matrix, a polysaccharide, to enhance the stability in aqueous media. Films obtained by casting were characterized by thermal analysis, chemical imaging, swelling behaviour and cell adhesion.

Animals↗

PubMed2005

The relevance of the transfer of molecular information between natural and synthetic materials in the realisation of biomedical devices with enhanced properties.

Past and recent attempts to introduce in synthetic polymers molecular information from natural substances through simple blending, template polymerization and molecular imprinting are reviewed. The most promising approaches that can open the way to the realisation of new materials with improved biocompatibility, antibody- or enzyme-like performances are analysed more deeply. The realisation of bioartificial blends from natural and synthetic polymers, molecularly imprinted nanospheres or membranes that can act as recognition element in (bio)sensing devices, as synthetic enzymes or as key constituents of body fluids purification tools is presented in order to make the reader aware of the fascinating possibilities that these techniques make available to the biomedical science and engineering in the close future. The last part of the paper describes recent attempts to insert recognition elements for large molecules as proteins, DNA segments, viruses or whole cells in synthetic polymer systems, in order to develop new systems in the treatments of diseases and for tissue-engineering applications.

Animals↗

PubMed2005

Molecularly imprinted bioartificial membranes for the selective recognition of biological molecules. Part 2: release of components and thermal analysis.

Molecularly imprinted membranes imprinted for a large-molecular-weight protein were realised using a blend of natural and synthetic polymers. Bioartificial membranes of synthetic (poly(ethylene-co-vinyl alcohol)-EVAL, Clarene) and biological (Dextran) polymers, molecularly imprinted with alpha-amylase as the template, were prepared and investigated. Dimethyl sulfoxide (DMSO) solutions of the alpha-amylase template, Clarene and Dextran were mixed under stirring in the desired proportions and dipped in DMSO (solvent)/water (non solvent) mixture, to obtain the phase separation. The release of Clarene, Dextran and alpha-amylase in the inversion baths was quantified by spectrophotometric methods and final composition of membranes was established. To study the interactions between the polymer components and between polymeric materials and the template, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out. Results indicated that stable and continuous bioartificial membranes of Clarene and Dextran can be obtained, whereby calorimetric analysis suggested the presence of high interaction between alpha-amylase and the Clarene component.

Biocompatible Materials↗

PubMed2004

Acrylic polymeric nanospheres for the release and recognition of molecules of clinical interest.

Cross-linked poly(methylmethacrylate-co-methacrylic acid) nanospheres were imprinted with theophylline through template radical polymerisation in diluted acetonitrile solution. This study will focus on the effect of functional monomer nature used (methylmethacrylate and/or methacrylic acid) in the recognition and in the release of template in order to develop a material with combined properties of drug delivery and rebinding for clinical applications. After template extraction the nanospheres showed satisfactory recognition properties (up to 1mg template/g of polymer). Moreover polymers prepared selectively removed theophylline with a theophylline rebinding of 5.1 times higher than that of caffeine, a compound of similar structure. Drug release properties were also satisfactory (up to 95% of loaded theophylline in 7 days).

Acrylic Resins↗

PubMed2004

Molecularly imprinted bioartificial membranes for the selective recognition of biological molecules.

Membranes of a synthetic (poly(ethylene-co-vinyl alcohol), Clarene) and a biological (dextran) polymer, imprinted with alpha-amylase, of different compositions were prepared by the phase-inversion process. Membrane morphologies were shown to be dependent on the synthetic-biological components composition. The removal of the template from the membranes was performed by extraction with water, while an aqueous solution of alpha-amylase was permeated across the membranes under pressure to obtain the rebinding of the template. The selectivity of alpha-amylase-imprinted membranes was investigated by the same uptake experiment using pepsin, albumin and amyloglucosidase, and the rebinding of these proteins was compared with that of the print molecule. Before and after template extraction and after the rebinding experiment, kinetic measurements of the imprinting molecule were conducted to estimate the activity of the enzyme immobilised in the polymer matrix. Results obtained revealed that the immobilised enzyme maintains a good functionality while in the membrane compared to the free enzyme and the imprinted 'bioartificial' dextran and Clarene membranes, obtained by the phase-inversion method, can establish efficient interaction with alpha-amylase as template molecule, as confirmed by the fair selectivity in rebinding tests.

Carbohydrate Sequence↗

PubMed2001

The treatment and reuse of wastewater in the textile industry by means of ozonation and electroflocculation.

Two different oxidation treatments, ozonation and electroflocculation, were experimented on a pilot scale to test their efficiency in removing polluting substances from wastewaters of textile industries. Both pilot plants used reproduced very closely a full-scale treatment in order to obtain indications about the feasibility of a transfer on industrial scale. By means of ozone treatment very high colour removal (95-99%) was achieved and treated waters were reused satisfactorily in dyeing even with light colours. This evidence despite the fact that the chemical oxygen demand of treated waters was still in a range (75-120 mg/l, a decrease up to 60%) that was usually considered to be too high for recycling purposes, especially for dyeing light colours. Treating plants working at the above-mentioned conditions should guarantee low operating costs. A biological pre-treatment and a sand filtration are absolutely essential. The transfer on industrial scale of the treatment is currently under development under an already financed European project. Electrochemical treatment showed to be very efficient in removing colour (80-100%) and chemical oxygen demand (70-90%). Moreover, a sensible decrease of chloride and sulphate ions was detected. Removal of flocculated material (post-treatment) must be, however, perfected in order to establish a correct costs-to-benefits ratio and therefore, propose an implementation of the technique on an industrial scale.

Color↗

PubMed2001

Bioartificial polymeric materials based on polysaccharides.

Bioartificial polymeric materials, based on blends of polysaccharides with synthetic polymers such as poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA), were prepared as films or hydrogels. The physico-chemical, mechanical, and biological properties of these materials were investigated by different techniques such as differential scanning calorimetry, dynamic mechanical thermal analysis, scanning electron microscopy, and in vitro release tests, with the aim of evaluating the miscibility of the polymer blends and to establish their potential applications. The results indicate that while dextran is perfectly miscible with PAA, dextran/PVA, chitosan/PVA, starch/PVA, and gellan/PVA blends behave mainly as two-phase systems, although interactions can occur between the components. Cross-linked starch/PVA films could be employed as dialysis membranes: they showed transport properties comparable to, and in some cases better than, those of currently used commercial membranes. Hydrogels based on dextran/PVA and chitosan/PVA blends could find applications as delivery systems. They appeared able to release physiological amounts of human growth hormone, offering the possibility to modulate the release of the drug by varying the content of the biological component.

Biocompatible Materials↗

PubMed2001

Ozone treatment of textile wastewaters for reuse.

Treatment of textile wastewaters by means of an ozonation pilot plant are described. Wastewaters used were produced by a dyeing and finishing factory and were first treated in an active sludge plant and filtrated through sand. In the appropriate conditions very high colour removal (95-99%) was achieved and the effluent could be reused in production processes requiring water of high quality as dyeing yarns or light colorations. Even if the chemical oxygen demand of treated waters was still in a range (75-120 mg/l, a decrease of up to 60%) that was usually considered to be too high for recycling purposes, recycling experiments were successful. The economical viability of the techniques implementation was also demonstrated and the industrial plant is currently under realisation under an EU financed project. The paper considers also the possible improvement of ozone diffusion by means of membrane contactors realised in a second pilot plant, in order to further reduce operating costs of the technique. With respect to traditional systems, the gas/liquid contact surface is much higher being that of the membrane. Ozone at the interface is therefore immediately solubilized and potentially consumed with no additional resistance to the mass transfer.

Coloring Agents↗

PubMed1998

Degradable and highly porous polyesterurethane foam as biomaterial: effects and phagocytosis of degradation products in osteoblasts.

Recently, a new class of biodegradable PHB-based polyesterurethane (DegraPol/btc) has been prepared and found to exhibit favorable cell and tissue compatibility. The present study has been designed to evaluate the response of primary isolated rat tibia osteoblasts to small crystalline particles of short-chain poly[(R)-3-hydroxybutyric acid] (PHB-P diameter: 2-20 microm), of fluorescent-labeled analogs (DPHP-P), and of lysine methyl ester as possible degradation products of DegraPol/btc. Observations made using confocal microscopy clearly indicate that osteoblasts have the capability of taking up PHB-P particles. Although in single-cell analysis the number of DPHB-P-positive osteoblasts gradually increased up to 16 days, the fluorescence intensity per osteoblast increased only during the first 4 h after DPHB-P incubation, and then it retained the 4 h level up to 16 days. No significant change in the production levels of collagen type I and osteocalcin was detectable after treatment with low concentrations of PHB-P for up to 32 days. In contrast, a time- and dose-dependent alteration of the alkaline phosphatase (ALP) activity was found. Maximal activity was measured after 4 days of treatment with 2 microg of PHB-P/mL (170% of control cells). Rat peritoneal macrophages co-cultured with osteoblasts in a transwell culture system mimicked the observed PHB-P induced ALP elevation. Therefore, the PHB-P-induced ALP increase could be the result of direct or indirect stimulation of osteoblasts, possibly via soluble factors produced by contaminating osteoclasts. Taken collectively, the data demonstrate that osteoblasts are capable of phagocytosing PHB-P and that this process is accompanied at low PHB-P concentrations by dose- and time-dependent alteration of alkaline phosphatase activity but not of collagen type I or osteocalcin.

Alkaline Phosphatase↗

PubMed1996

Characterization of the cell response of cultured macrophages and fibroblasts to particles of short-chain poly[(R)-3-hydroxybutyric acid].

The known biodegradability of poly[(R)-3-hydroxybutyric acid] (PHB) in certain biological environments had led to its proposed use as a biodegradable, biocompatible polymer. Recently, a new, rapidly biodegradable block copolymer that contains crystalline domains of PHB blocks has been synthesized. During degradation of these polymers, the PHB domains are transformed in a first step into small crystalline particles of short-chain PHB. Therefore, particles of short-chain poly[(R)-3-hydroxybutyric acid] (Mn 2300) (PHB-P), as possible degradation products, are investigated here for their effects on the viability and activation of mouse macrophages (J774), primary rat peritoneal macrophages, and mouse fibroblasts (3T3), and their biodegradation or exocytosis (or both) in these cells. Results obtained in the present study indicate that incubation of macrophages with PHB-P concentrations higher than 10 micrograms/mL were found to cause a significant decrease in the number of attached and viable cells as measured in MTT assay, and significant increase in the production levels of tumor necrosis factor-alpha (TNF-alpha) or nitric oxide (NO). At low concentrations, particles of PHB failed to induce cytotoxic effects or to activate macrophages. In addition, signs of possible biodegradation were seen in macrophages. Fibroblasts showed only limited PHB-P phagocytosis and no signs of any cellular damage or cell activation (production of collagen type I and IV, and fibronectin). Taken collectively, the present data indicate that phagocytosis of PHB-P at high concentrations ( > 10 micrograms/mL) is dose dependent and associated with cell damage in macrophages but not in fibroblasts.

3T3 Cells↗

PubMed1996

Interactions of osteoblasts and macrophages with biodegradable and highly porous polyesterurethane foam and its degradation products.

The macrophage cell line J774, primary rat osteoblasts, and the osteoblast cell line MC3T3-E1 were used to examine the biocompatibility of a newly developed polyesterurethane foam and the possible use of this structure as bone-repair materials. The newly developed, biodegradable, and highly porous (pore size 100-150 microns) DegraPol/btc polyesterurethane foam was found to exhibit good cell compatibility; the cell-to-substrate interactions induced neither cytotoxic effects nor activation of macrophages. Osteoblasts and macrophages exhibited normal cell morphology. No signs of cell damage were detected using scanning electron microscopy (SEM). No significant increase in the production of tumor necrosis factor-alpha (TNF-alpha) or nitric oxide (NO) was detected in macrophages. Compared with cells cultured on tissue culture polystyrene (TCPS), macrophages exhibited relatively high cell attachment (150% of TCPS) but significantly high doubling time (about 8 days) compared with TCPS (4.6 days). Primary rat osteoblasts and the osteoblast cell line exhibited relatively high attachment (140% and 180% of TCPS, respectively) and a doubling time of about 5 days, compared with TCPS (6 days and 8.8 days, respectively). Eight days after cell seeding, osteoblasts exhibited a confluent cell multilayer and migrated into the pores of the polymer. In addition they produced high concentrations of collagen type I, the main protein of the bone, and expressed increasing alkaline phosphatase activity and osteocalcin production throughout the 12 days of the experiment. During degradation of these polymers, small crystalline particles of short-chain poly[(R)-3-hydroxybutyric acid] (M(n) approximately 2300) (PHB-P) are released. Therefore PHB-P (diameter, 2-20 microns), as possible degradation products of the polymer, are investigated here for their effects on macrophages and osteoblasts. Results obtained in the present study clearly indicate that macrophages and, to a lesser degree, osteoblasts have the ability to take up (phagocytose) PHB-P. At low concentrations particles of PHB failed to induce cytotoxic effects or to activate macrophages. Osteoblasts showed only limited PHB-P phagocytosis and no signs of cellular damage. At high concentrations of PHB-P, this process was accompanied by cytotoxic effects in macrophages (> 200 pg PHB-P/cell) and to a lesser extent in osteoblasts (> 400 pg PHB-P/cell).

Animals↗