Biomaterials (v.26, #19)
Comparative study on the properties of acrylic bone cements prepared with either aliphatic or aromatic functionalized methacrylates
by Jose M. Cervantes-Uc; Vazquez-Torres Humberto Vázquez-Torres; Cauich-Rodriguez Juan Valerio Cauich-Rodríguez; Vazquez-Lasa Blanca Vázquez-Lasa; San Roman del Barrio Julio San Román del Barrio (pp. 4063-4072).
Bone cements prepared with methacrylic acid (MAA) and diethyl amino ethyl methacrylate (DEAEM) were compared with formulations employing 4-methacryloyloxybenzoic acid (MBA) and 4-diethyaminobenzyl methacrylate (DEABM) as comonomer. The influence of these new aromatic monomers on various physicochemical, setting and mechanical properties was assessed. Surface characterization demonstrated that bone cements prepared with any of the functionalized monomers exhibited increasing hydrophilicity with monomer concentration and that the aromatic monomers provided more hydrophilic cements than their aliphatic counterparts for low concentrations of the functional monomer. It was also found that bone cements prepared with high amounts of the acidic aliphatic monomer provided the highest exotherm of reaction and their setting times were shorter than MBA based cements. On the other hand, DEABM containing bone cements exhibited shorter setting times than DEAEM formulations and slightly higher peak temperatures. In general, it was found that the glass transition temperature increased with the presence of acidic comonomer and decreased when alkaline comonomers were present, especially aliphatic ones.When aromatic methacrylates were used at 0.05molar fraction, the highest tensile and compressive strength were achieved i.e. 46 and 118MPa for MBA and 51 and 108MPa for DEABM formulations. A further increase in the aromatic monomer concentration led to cements of low mechanical properties due to solubility problems as revealed by SEM.
Keywords: Acrylic bone cements; Mechanical properties; 4-methacryloyloxybenzoic acid; Diethyaminobenzyl methacrylate
Development of a strontium-containing hydroxyapatite bone cement
by Dagang Guo; Kewei Xu; Xiaoyun Zhao; Yong Han (pp. 4073-4083).
A new route was developed to synthesis a new type of strontium-containing hydroxyapatite (Sr-HAP) bone cement with precursors of tetracalcium phosphate (TTCP), strontium hydrogen phosphate (DSPA), dicalcium phosphate (DCPA), phosphate acid and water. The processing parameters and fundamental properties including pH value, setting time, compressive strength of final hardened body and the cytotoxicity for serial extracts of each cements were investigated. The result shows that the final product of the cement after setting for 24h is nonstoichiometic Sr-containing hydroxyapatite (Ca10âˆ’ mâˆ’ xSr xâ–¡ m(HPO4) y(PO4)6âˆ’ y(OH)2âˆ’2 mâ–¡2 m, 0< x<1, nSr-HAP) and no other harmful impurities were detected. The pH value of Sr-containing cement pastes approaches to 7.0â€“7.6 when they are mixed with a ratio of 1:1 of powder to liquid ( P/L) in weight. The setting time of the cement pastes is 4â€“11min for the initial one and 10â€“17min for the final one when the concentration of diluted phosphate is in a range of 0.5â€“1.0mol/l. The compressive strengths of the hardened cements with different molar ratios of Sr/(Sr+Ca) after subjected an immersion in simulated body fluid (SBF) increase uniformly from 1 day to 5 days, where they get maximum values, respectively, but then decrease till to 2 weeks. Especially for the CPC-1, with a Sr/(Sr+Ca) molar ratios of 5% in cement powder composition, the largest compressive strength gained at 5 days is 66.57MPa and the lowest one gained at 2 weeks is 44.75MPa, which matches the value of human bones and can be expected to use in clinic application in repairing the nonloading sites on account of the positive result of cytotoxicity test of the extracts of Sr-containing calcium phosphate cement (Sr-CPC).
Keywords: Calcium phosphate cement; Sr-containing hydroxyapatite; Biocompatibility; Cytotoxicity
Nanocrystalline hydroxyapatite coatings on titanium: a new fast biomimetic method
by Adriana Bigi; Elisa Boanini; Barbara Bracci; Alessandro Facchini; Silvia Panzavolta; Francesco Segatti; Luigina Sturba (pp. 4085-4089).
We obtained a fast biomimetic deposition of hydroxyapatite (HA) coatings on Ti6Al4V substrates using a slightly supersaturated Ca/P solution, with an ionic composition simpler than that of simulated body fluid (SBF). At variance with other fast deposition methods, which produce amorphous calcium phosphate coatings, the new proposed composition allows one to obtain nanocrystalline HA.Soaking in supersaturated Ca/P solution results in the deposition of a uniform coating in a few hours, whereas SBF, or even 1.5SBF, requires 14 days to deposit a homogeneous coating on the same substrates. The coating consists of HA globular aggregates, which exhibit a finer lamellar structure than those deposited from SBF. The extent of deposition increases on increasing the immersion time. Transmission electron microscope (TEM) images recorded on the material detached from the coating show that the deposition is constituted of thin nanocrystals. Electron diffraction (ED) patterns recorded from most of the crystals exhibit the presence of rings, which can be indexed as reflections characteristic of HA. Furthermore, several HA single-crystal spot ED images were obtained from individual crystals.
Keywords: Biomimetic coatings; Hydroxyapatite; Ti6Al4V; SEM; TEM-ED
The effect of camphorquinone (CQ) and CQ-related photosensitizers on the generation of reactive oxygen species and the production of oxidative DNA damage
by Dustin Pagoria; Abert Lee; Werner Geurtsen (pp. 4091-4099).
Recent evidence suggests that following visible-light (VL) irradiation, CQ and the CQ-related photosensitizers benzil (BZ), benzophenone (BP), and 9-fluorenone (9-F) generate initiating radicals that may indiscriminately react with molecular oxygen forming reactive oxygen species (ROS). The purpose of this investigation was to determine whether VL-irradiated CQ, BZ, BP, and 9-F cause DNA damage due to the generation of ROS in vitro. ROS formation by CQ and CQ-related photosensitizersÂ±dimethyl- p-toluidine (DMT) was investigated in a cell-free system with VL irradiation. DNA damage was determined using Î¦X-174 RF I supercoiled double-stranded plasmid DNA and ROS quantified with 4-((9-acridinecarbonyl)amino)-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO-9-AC), a fluorogenic ROS-sensitive probe. VL-irradiated CQ, BZ, BP, and 9-F (Â±DMT) produced significant DNA damage at 0.1, 0.5, and 1.0mM and in a concentration-dependent manner ( p<0.05). TEMPO-9-AC revealed that all investigated VL-irradiated photosensitizers produced significant amounts of ROS with BZ in the presence of DMT generating the most ROS after 30, 60, and 90min. VL-irradiated CQ, BZ, BP, and 9-F Â±DMT continued to generate significant amounts of ROS 90min after VL irradiation. As a result, future investigations should evaluate the effect of VL-irradiated photosensitizers in cells and possible protective effects provided by antioxidants.
Keywords: Camphorquinone; Photosensitizers; Reactive oxygen species; Oxidative DNA damage
Response of intestinal cells and macrophages to an orally administered cellulose-PEG based polymer as a potential treatment for intractable edemas
by Annaclaudia Esposito; Alessandro Sannino; Anna Cozzolino; Sergio Nappo Quintiliano; Monica Lamberti; Luigi Ambrosio; Luigi Nicolais (pp. 4101-4110).
The elimination of water from the body represents a fundamental therapeutic goal in those diseases in which oedemas occur.Aim of this work is the design of a material able to absorb large amount of water to be used, by oral administration, in those cases in which resistance to diuretics appears.Sorption and mechanical properties of the cellulose based superabsorbent hydrogel acting as a water elimination system have been modulated through the insertion of molecular spacers between the crosslinks. Starting polymers are the sodium salt of carboxymethylcellulose (CMCNa), a polyelectrolyte cellulose derivative, and the hydroxyethylcellulose (HEC), a non-polyelectrolyte derivative. Polyethyleneglycol (PEG) with various molecular weights, has been linked by its free ends at two divinylsulfone (DVS) crosslinker molecules, in order to increase the average distance between two crosslinking sites and thus acting as spacer. Both the effect of concentration and molecular weight of the spacer resulted to significantly affect the hydrogel final sorption properties and thus the efficiency of the body water elimination system. Biocompatibility studies have been performed to test the hydrogel compatibility with respect to intestinal and macrophages cell lines. To investigate the effects of intestinal cells conditioned media after the contact with the gel on macrophages nitric oxide release tests have been carried out.
Keywords: Hydrogels; Cross-linking; Swelling; Macrophage; Intestinal cells; Biocompatibility
The effect of triethylene glycol dimethacrylate on the cell cycle of mammalian cells
by Helmut Schweikl; Inge Altmannberger; Nico Hanser; Karl-Anton Hiller; Carola Bolay; Gero Brockhoff; Gianrico Spagnuolo; Kerstin Galler; Gottfried Schmalz (pp. 4111-4118).
The induction of DNA damage by a genotoxic agent is a signal leading to cell cycle delay, and thereby enables and induces DNA repair prior to cell cycle progression. Triethylene glycol dimethacrylate (TEGDMA), a monomer of dental resinous materials, caused mutagenic effects in mammalian cells probably as a consequence of DNA damage. Therefore, we hypothesized that TEGDMA will induce a cell cycle delay in mammalian cells. Here, cell lines deficient and proficient of a functional p53 tumor suppressor protein were used to study the effects of TEGDMA on the various phases of the cell cycle. V79 Chinese hamster lung fibroblasts (p53 deficient), N1 human skin fibroblasts (p53 proficient), and primary human pulp fibroblasts (p53 proficient) were exposed to increasing TEGDMA concentrations (0â€“3mmol/l). Cell survival and vitality were determined after a 24-h exposure period and a 24-h recovery period, and the distribution of cells between the phases of the cell cycle in untreated and TEGDMA-treated cultures was analyzed by flow cytometry. The majority of the TEGDMA-treated V79 cells accumulated in G2 phase. In contrast, about 30% of human N1 fibroblasts were reversibly blocked in G1 phase by 0.5â€“3.0mmol/l TEGDMA. The fraction of G2-phase cells was increased only by high TEGDMA concentrations. The percentage of human pulp cells in G1 phase increased very slightly with 1mmol/l TEGDMA, but cell numbers in G1 phase were reduced by 10â€“20% by 1.5â€“3mmol/l TEGDMA. The percentage of pulp cells in G2 phase increased about 2-fold without any obvious effect of a 24-h recovery period. Therefore, TEGDMA caused cell cycle delays through p53-dependent and independent pathways in the various cell lines. From these results, we conclude that TEGDMA may influence physiological processes like cell growth and differentiation of human pulp cells in vivo.
Keywords: Dental resin; TEGDMA; Cell cycle; Human pulp cells; Proliferation
Inflammatory response to peritoneal implantation of alginateâ€“poly-l-lysine microcapsules
by Robert Robitaille; Julie Dusseault; Nathalie Henley; Karine Desbiens; Nathalie Labrecque; J.-P. Halle Jean-Pierre Hallé (pp. 4119-4127).
A thorough understanding of the mechanisms involved in the host reaction to alginateâ€“poly-l-lysine microcapsules (HRM) is important to design methods for the evaluation, selection, and development of biocompatible biomaterials and microcapsules or treatments to control this reaction. The objective of this study was to identify those immune cells and cytokines involved in the pathogenesis of the HRM. The total and differential cell counts were evaluated, and the mRNA expression of TNF- Î±, IL-1 Î², IL-6 and TGF- Î²1 was measured in peritoneal washings at 3, 17, 48, 96 and 168h after saline or microcapsule injections. Neutrophil number and IL-1 Î² and IL-6 m-RNA expression presented an early transient increase, with no differences between saline and microcapsule injections, suggesting a reaction to the procedure. Macrophages, lymphocytes and TNF- Î± were significantly more activated over a longer period of time, after microcapsule implantation than saline injection. They are likely involved in transforming the reaction into a chronic inflammatory process. TGF- Î²1 and IL-1 Î² presented a late (day 7) significant increase after microcapsule but not saline injections. They are likely involved in transforming the reaction into a fibrogenic process. These results suggest that macrophages, lymphocytes, TNF- Î±, IL-1 Î² and TGF- Î²1 play a role in the pathogenesis of the HRM.
Keywords: Biocompatibility; Macrophage; Interleukin; TGF; Cytokine; Microcapsule
A comparative radiological assessment of polylactide pins over 3 years in vivo
by Axel Prokop; Axel Jubel; Ulrich Hahn; Martin Dietershagen; Mirko Bleidistel; Christiane Peters; Andreas Höfl; Klaus E. Rehm (pp. 4129-4138).
Biodegradable polylactide implants allow secure fixation of osteochondral fractures with minimal adverse effects. The goal of this prospective, randomized animal study was to show whether osteoconductive effects can be achieved through the development of poly-l/dl(70/30)lactide composite implants with 10% Î²-tricalcium phosphate, and whether degradation can be positively influenced and adverse effects minimized using such implants. An additional goal was to clarify which radiological procedure is most suitable to observe the course of follow-up.Thirtysix medial femoral condyle osteotomies of sheep were fixed with either 3 poly-l/dl-lactide pins or 3 composite pins, and the pin canal widths were measured with conventional radiographs, with CT, MRI, and histologically after 3, 18, and 36 months.All fractures healed completely without displacement or clinically relevant complications. The pin canals dilated secondary to pin degradation at the 12th month, and then decreased in size later. At 36 months, the pins had microscopically disappeared, and the canals were filled with bone or scar tissue. There were no statistically significant differences between the pin-types.Poly-l/dl-lactide pins and composite C-pins are suitable for secure fixation of small osteochondral fractures. Osteoconductive effects of biocompatibility or osseous integration relating to composite development were not evident. Conventional radiography and computer tomography were suitable techniques for observation of pin canals. Due to frequently observed artifact, MRI was not suitable to observe the course of the implants.
Keywords: Polylactic acid; Composite; Calcium phosphate; Osteolysis; Biodegradation
Guided bone regeneration membrane made of polycaprolactone/calcium carbonate composite nano-fibers
by K. Fujihara; M. Kotaki; S. Ramakrishna (pp. 4139-4147).
In this study, new type of guided bone regeneration (GBR) membranes were fabricated by polycaprolactone (PCL)/CaCO3 composite nano-fibers with two different PCL to calcium carbonate (CaCO3) ratios (PCL:CaCO3=75:25wt% and 25:75wt%). The composite nano-fibers were successfully fabricated by electrospinning method and CaCO3 nano-particles on the surface of nano-fibers were confirmed by energy disperse X-ray (EDX) analysis. In order to achieve mechanical stability of GBR membranes, composite nano-fibers were spun on PCL nano-fibrous membranes which has high tensile strength, i.e., the membranes consist of two layers of functional layer (PCL/CaCO3) and mechanical support layer (PCL). Two different GBR membranes were prepared, i.e., GBR membrane (A)=PCL:CaCO3=75:25wt%+PCL, GBR membrane (B)=PCL:CaCO3=25:75wt%+PCL. Osteoblast attachment and proliferation of GBR membrane (A) and (B) were discussed by MTS assay and scanning electron microscope (SEM) observation. As a result, absorbance intensity of GBR membrane (A) and tissue culture polystyrene (TCPS) increased during 5 days seeding time. In contrast, although absorbance intensity of GBR membrane (B) also increased, its value was lower than membrane (A). SEM observation showed that no significant difference in osteoblast attachment manner was seen on GBR membrane (A) and (B). Because of good cell attachment manner, there is a potential to utilize PCL/CaCO3 composite nano-fibers to GBR membranes.
Keywords: Bone regeneration; Calcium carbonate; Cell adhesion; Nano-composite
Application of a polyelectrolyte complex coacervation method to improve seeding efficiency of bone marrow stromal cells in a 3D culture system
by Y.-C Yi-Chin Toh; Saey Tuan Ho; Yi Zhou; Dietmar W. Hutmacher; Hanry Yu (pp. 4149-4160).
High seeding efficiency with homogenous distribution of limited cell sources such as bone marrow stromal cells (BMSCs) are of clinical relevance in scaffold-based tissue engineering. Therefore, considerable research efforts have been invested to ameliorate the seeding efficiency in 3D scaffolds. Preliminary data demonstrated that indeed BMSCs were viable and were able to proliferate in a model 3D scaffold, i.e. Cytomatrix® scaffold. However, the eventual practical application of BMSCs in such 3D scaffolds is limited by the low seeding efficiency of the cells within the scaffold. Here, we demonstrated that the cell seeding efficiency of BMSCs in the Cytomatrix® scaffold can be improved significantly ( t-test,p<0.05) by means of macroencapsulating the scaffold via the complex coacervation of a methylated collagen and terpolymer. The thickness and density of the polyeletrolyte complex can be modulated by the contact time between the methylated collagen and terpolymer to balance between cell entrapment efficacy and mass transfer impedance imparted by the complex. Porcine BMSCs were macroencapsulated in Cytomatrix® scaffolds using various polyelectrolyte contact time and cultured under both static and dynamic conditions. Throughout the range of contact time investigated, macroencapsulation did not affect the viability of the porcine BMSCs in dynamic culture. However, the viability of the cells under static cultures was compromised with longer polyelectrolyte contact time. Therefore, this proposed method of macroencapsulation enables customization to achieve enhanced seeding efficiency without mass transfer impedance for different culture configurations.
Keywords: Bone marrow stromal cells; Scaffolds; Seeding efficiency; Macroencapsulation
Role of hydroxyapatite coating in resisting wear particle migration and osteolysis around acetabular components
by Melanie Jean Coathup; James Blackburn; Allen E. Goodship; James L. Cunningham; Tracey Smith; Gordon W. Blunn (pp. 4161-4169).
The main problem facing the longevity of total joint replacements is wear particle-induced osteolysis, particularly around the acetabular component. Ovine Total Hip Replacement surgery was performed with roughened femoral heads in order to enhance wear debris generation in vivo. The resistance to aseptic loosening of acetabular components with different surface coatings was investigated. Implants remained in vivo for 1 year.Sheep were randomly assigned to one of six experimental groups where the acetabular cup was fixed utilising an: (a) cemented polyethylene acetabular cup, (b) metal backed grit blasted surface, (c) metal backed plasma sprayed titanium porous coating, (d) metal backed sintered beaded coating, (e) Hydroxyapatite (HA)-coated grit blasted surface (f) and HA-coated porous components. Ground Reaction Force (GRF) was used to asses the functional performance of the implants and data was collected pre-operatively and at 12, 24, 36 and 52 weeks post op. Wear debris generated was analysed and radiographs taken prior to preparation of thin sections. Fibrous tissue (FT) thickness and bone contact at 1mm intervals along the acetabular boneâ€“implant interface was calculated.GRF data demonstrated significant differences between experimental groups. In all groups there was an increase in the function of the hip after surgery and up to 24 weeks but thereafter the function of the group with the grit blasted surface reduced whereas the function of the other groups did not significantly change. Average wear particles generated were <1Î¼m in size. The cemented group demonstrated a significantly thicker average FT layer (2.69mm) when compared with all other groups ( p<0.05 in all cases) except the grit blasted group (1.56mm). HA porous coated cups demonstrated significantly least fibrous tissue adjacent to its interface when compared with all other groups (cemented p<0.05, grit blasted p=0.029, porous p<0.05, sintered beads p<0.05 and HA grit blasted p<0.05). Significantly increased bone contact to HA-coated porous cups (73.33%) when compared with all groups was identified except HA-coated grit blasted cups where no significant difference was demonstrated. Radiographic signs of loosening were visible in all groups except the HA-coated porous group.Results demonstrated that HA porous coated acetabular components significantly enhanced bone ingrowth in the presence of wear particles, preventing their migration and reducing osteolysis. Non-HA-coated porous and sintered beaded components provided a more effective seal against the ingress of wear debris when compared with cemented cups.
Keywords: Animal model; Bone ingrowth; Foreign body response; Hydroxyapatite; Osteolysis; Wear debris
Release of angiogenic growth factors from cells encapsulated in alginate beads with bioactive glass
by Hussila Keshaw; Alastair Forbes; Richard M. Day (pp. 4171-4179).
Attempts to stimulate therapeutic angiogenesis using gene therapy or delivery of recombinant growth factors, such as vascular endothelial growth factor (VEGF), have failed to demonstrate unequivocal efficacy in human trials. Bioactive glass stimulates fibroblasts to secrete significantly increased amounts of angiogenic growth factors and therefore has a number of potential applications in therapeutic angiogenesis. The aim of this study was to assess whether it is possible to encapsulate specific quantities of bioactive glass and fibroblasts into alginate beads, which will secrete growth factors capable of stimulating angiogenesis. Human fibroblasts (CCD-18Co) were encapsulated in alginate beads with specific quantities of 45S5 bioactive glass and incubated in culture medium (0â€“17 days). The conditioned medium was collected and assayed for VEGF or used to assess its ability to stimulate angiogenesis by measuring the proliferation of human dermal microvascular endothelial cells. At 17 days the beads were lysed and the amount of VEGF retained by the beads measured. Fibroblasts encapsulated in alginate beads containing 0.01% and 0.1% (w/v) 45S5 bioactive glass particles secreted increased quantities of VEGF compared with cells encapsulated with 0% or 1% (w/v) 45S5 bioactive glass particles. Lysed alginate beads containing 0.01% and 0.1% (w/v) 45S5 bioactive glass contained significantly more VEGF ( p<0.01) compared with beads containing no glass particles. Endothelial cell proliferation was significantly increased ( p<0.01) by conditioned medium collected from alginate beads containing 0.1% (w/v) 45S5 bioactive glass particles. The results of this study demonstrate that bioactive glass and fibroblasts can be successfully incorporated into alginate beads for use in delivering angiogenic growth factors. With further optimization, this technique offers a novel delivery device for stimulating therapeutic angiogenesis.
Keywords: Alginate; Angiogenesis; Boactive glass; Growth factors
Analysis of the shelf life of a two-solution bone cement
by J.B. Shim; S.J. Warner; J.M. Hasenwinkel; J.L. Gilbert (pp. 4181-4187).
Two-solution bone cement consists of methyl methacrylate monomer and poly(methyl methacrylate) polymer dissolved together to yield a viscous solution. Two solutions are used such that the initiator, benzoyl peroxide (BPO), is placed in one solution and the activator, N, N, dimethyl- para-toluidine, is placed in the other. This approach to bone cement provides for a simplified use during surgery and eliminates some of the sources of porosity formation. However, the BPO-containing solution cement will spontaneously polymerize over time and will limit the useful shelf life of this component of the system. The activator-containing component is much more stable and is not as susceptible to spontaneous polymerization. In making two-solution cements, it is envisioned that antibiotics may be incorporated and that the polymer may be sterilized using Î³(gamma)-irradiation. Therefore, this study investigated the shelf life of the initiator-containing solution bone cement and studied the effects of initiator concentration, Î³-irradiation, gentamicin addition, and the role of storage temperature. Isothermal differential scanning calorimetry (Iso-DSC) techniques were used to monitor the polymerization of BPO-containing solutions. It was found that the shelf life was highly temperature dependent and followed an Arrhenius expression where refrigeration storage (4Â°C) yielded approximately a 12-month storage time, while 70Â°C storage results in setting in about 5â€“7min. Î³-irradiation and gentamicin addition did not significantly affect the shelf life. Initiator concentration affected storage time with higher levels resulting in shorter shelf life.
Keywords: Bone cement; Shelf life; Iso-DSC; Spontaneous thermal polymerization; BPO; Antibiotics; Î³; -irradiation; Arrhenius; expression
Conjugated poly(D,L-lactide- co-glycolide) for the preparation of in vivo detectable nanoparticles
by G. Tosi; F. Rivasi; F. Gandolfi; L. Costantino; M.A. Vandelli; F. Forni (pp. 4189-4195).
Cellular localization of nanoparticles (Np) represents an important target in the understanding of their distribution after endovenous injection. The need of suitable devices and methodologies capable to detect Np in tissues or in cellular districts can be satisfied by Np which have to be easily recognizable by simple methods. Conjugations of poly(D,L-lactide- co-glycolide) with fluorescein and biotin allow fluorescent and immuno-histochemically active Np to be obtained. The fluorescein Np are detectable using fluorescent microscopy whereas biotin Np can be detected by optical microscopy after streptavidinâ€“biotinâ€“peroxidase complexation. In vivo experiments confirm the ability of these particles to be easily detected in the brain parenchyma or in the liver cell population according to the infusion pathway.
Keywords: Nanoparticles; Fluoresceinâ€“PLGA conjugate; Biotin-PLGA conjugate; In vivo localization
Monitoring cell adhesion processes on bioactive polymers with the quartz crystal resonator technique
by Delphine Le Guillou-Buffello; Gérard Hélary; Marcel Gindre; Graciela Pavon-Djavid; Pascal Laugier; Véronique Migonney (pp. 4197-4205).
The Thickness Shear Mode (TSM) quartz crystal resonator has been extensively used as sensitive sensor in various electrochemical and biological applications. This technique based on the propagation of an ultrasonic shear wave generated by a sinusoidal electric field through a piezoelectric quartz resonator, provides a non-destructive and powerful means to probe changes at solidâ€“solid or solidâ€“liquid interfaces. In this study, TSM was used to characterize cellâ€“polymer interactions developing during the cell adhesion process. TSM sensing was used to monitor the inhibiting properties of bioactive polymers towards fibroblast McCoy adhesion processes. For this purpose, thin films of various bioactive polymers exhibiting either carboxylate or/and sulfonate functional groups were deposited onto the TSM. Measurements of the time variation of the electrical motional resistance in the vicinity of the mechanical sensor resonant frequency were performed as the quartz crystal resonator was either coated with the continuous polymer phase or polymer plus cell suspensions. Cell adhesion processes on these surfaces was investigated by cell counting and the quartz resonator-based technique. Inhibition of fibroblast McCoy adhesion onto thin polymer films of various chemical compositions was analyzed and discussed in the perspective of a possible application of these bioactive polymers to fabricate intraocular lenses able to prevent secondary cataract phenomena.
Keywords: Biosensor; Cell adhesion; Bioactive polymers; Quartz crystal microbalance; Copolymer; Fibroblast