|Articles about Biomaterials|
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| Molecular handles open the door to novel biomaterials and cancer therapies
Veggeberg, S. (1998), Mol Med Today 4(5): 186.
| Molecular manipulation of microstructures: biomaterials, ceramics, and semiconductors
Stupp, S. I. and P. V. Braun (1997), Science 277(5330): 1242-8.
Abstract: Organic molecules can alter inorganic microstructures, offering a very powerful tool for the design of novel materials. In biological systems, this tool is often used to create microstructures in which the organic manipulators are a minority component. Three groups of materials-biomaterials, ceramics, and semiconductors-have been selected to illustrate this concept as used by nature and by synthetic laboratories exploring its potential in materials technology. In some of nature's biomaterials, macromolecules such as proteins, glycoproteins, and polysaccharides are used to control nucleation and growth of mineral phases and thus manipulate microstructure and physical properties. This concept has been used synthetically to generate apatite-based materials that can function as artificial bone in humans. Synthetic polymers and surfactants can also drastically change the morphology of ceramic particles, impart new functional properties, and provide new processing methods for the formation of useful objects. Interesting opportunities also exist in creating semiconducting materials in which molecular manipulators connect quantum dots or template cavities, which change their electronic properties and functionality.
| Molecular mechanisms of photoinduced oxygen evolution, PL emission, and surface roughening at atomically smooth (110) and (100) n-TiO2 (rutile) surfaces in aqueous acidic solutions
Nakamura, R., T. Okamura, et al. (2005), J Am Chem Soc 127(37): 12975-83.
Abstract: The success in preparing atomically smooth and stable (110) and (100) TiO2 (rutile) surfaces, combined with in situ photoluminescence (PL) and photocurrent measurements as well as atomic force microscopic (AFM) inspection, has enabled us to make systematic studies on molecular mechanisms of oxygen photoevolution and related processes on TiO2 (rutile), which are important for solar water splitting and photocatalytic environmental cleaning. The studies have revealed that various surface processes and properties, such as the flat-band potential (Ufb), the spectrum and intensity of the PL from a precursor of the oxygen photoevolution reaction, and photoinduced surface roughening, have all strong dependences on the atomic-level structure of the TiO2 surface. Importantly, all the results have been explained on the basis of our recently proposed new mechanism that the oxygen photoevolution reaction is initiated by a nucleophilic attack of an H2O molecule to a surface-trapped hole, thus giving confirmative evidence to it. The molecular mechanisms for photoinduced primary processes at the TiO2 surface, clarified in the present work, will provide a typical model for photoreactions on metal oxides in contact with aqueous solutions.
| Molecular modeling and site-directed mutagenesis of plant chloroplast monogalactosyldiacylglycerol synthase reveal critical residues for activity
Botte, C., C. Jeanneau, et al. (2005), J Biol Chem 280(41): 34691-701.
Abstract: Monogalactosyldiacylglycerol (MGDG), the major lipid of plant and algal plastids, is synthesized by MGD (or MGDG synthase), a dimeric and membrane-bound glycosyltransferase of the plastid envelope that catalyzes the transfer of a galactosyl group from a UDP-galactose donor onto a diacylglycerol acceptor. Although this enzyme is essential for biogenesis, and therefore an interesting target for herbicide design, no structural information is available. MGD monomers share sequence similarity with MURG, a bacterial glycosyltransferase catalyzing the transfer of N-acetyl-glucosamine on Lipid 1. Using the x-ray structure of Escherichia coli MURG as a template, we computed a model for the fold of Spinacia oleracea MGD. This structural prediction was supported by site-directed mutagenesis analyses. The predicted monomer architecture is a double Rossmann fold. The binding site for UDP-galactose was predicted in the cleft separating the two Rossmann folds. Two short segments of MGD (beta2-alpha2 and beta6-beta7 loops) have no counterparts in MURG, and their structure could not be determined. Combining the obtained model with phylogenetic and biochemical information, we collected evidence supporting the beta2-alpha2 loop in the N-domain as likely to be involved in diacylglycerol binding. Additionally, the monotopic insertion of MGD in one membrane leaflet of the plastid envelope occurs very likely at the level of hydrophobic amino acids of the N-terminal domain.
| Molecular orientation behavior of silk sericin film as revealed by ATR infrared spectroscopy
Teramoto, H. and M. Miyazawa (2005), Biomacromolecules 6(4): 2049-57.
Abstract: This paper reports the structure-dependent molecular orientation behavior of sericin, an adhesive silk protein secreted by silkworm, Bombyx mori. Although application of sericin as a biomaterial is anticipated because of its unique characteristics, sericin's physicochemical properties remain unclear, mainly because of its vulnerability to heat or alkaline treatment during separation from fibroin threads. This study employed intact sericin obtained from fibroin-deficient mutant silkworm to investigate the relationship between molecular orientation and the secondary structure of sericin. Sericin films were artificially stretched after moistening with aqueous ethanol of various concentrations. The resulting molecular orientation was analyzed using polarized infrared spectroscopy. These analyses indicated that formation of aggregated strands among extended sericin chains induced by ethanol treatment is the key to generating molecular orientation. Strong intermolecular hydrogen bonds are inferred to allow aggregated strands' stretching-force transmission, thereby causing molecular orientation.
| Molecular surface tailoring of biomaterials via pulsed RF plasma discharges
Panchalingam, V., B. Poon, et al. (1993), J Biomater Sci Polym Ed 5(1-2): 131-45.
Abstract: A pulsed RF plasma glow discharge is employed to demonstrate molecular level controllability of surface film deposits. Molecular composition of plasma deposited films is shown to vary in a significant manner with the RF duty cycle. Three fluorocarbon monomers are used to illustrate the process. All three exhibit a trend towards increased surface CF2 content with decreasing pulsed RF duty cycle, including exclusion of oxygen. Significant variations in carbon-fluorine surface functionalities are obtained over a controllable range of film thickness. Film growth rate measurements reveal the occurrence of surface reactions during significant portions of the off portion of the duty cycle. Albumin adsorption on fluorocarbon-treated PET films is unchanged from PET controls for a 100-fold range of bulk concentrations and 60-fold range of adsorption times. However, increased retention of albumin is observed following incubation with protein-denaturing sodium dodecyl sulfate solution, the retention decreasing with increasing bulk concentration of albumin. The increased retention of albumin suggests the treated surfaces may have promise as biocompatible materials.
| Molecular weight characteristics of alginate produced by Azotobacter vinelandii in a membrane bioreactor
Saude, N., H. Cheze-Lange, et al. (2001), Meded Rijksuniv Gent Fak Landbouwkd Toegep Biol Wet 66(3a): 321-4.
Abstract: A membrane bioreactor which combines a continuous fermentor and a cross-flow microfiltration module enabling continuous cell recycling and removal of the fermentation products freed of microbial cells was tested for the production of alginate by Azotobacter vinelandii. The molecular weight characteristics of the polysaccharide produced were investigated. The macromolecular characteristics of alginate recovered by first filtering batch fermentation broths through different microporous ceramic membranes with pore sizes varying from 0.45 to 1.4 microm seemed to be independent of the MPS. The 0.8-microm membrane pore size (MPS) was selected for continuous alginate production in the membrane bioreactor. A mean yield value of 0.21 g alginate g(-1) saccharose was obtained and an increase in alginate polydispersity as incubation proceeded was observed, probably due to enzymatic degradation of the polysaccharide.
| Molecularly engineered p(HEMA)-based hydrogels for implant biochip biocompatibility
Abraham, S., S. Brahim, et al. (2005), Biomaterials 26(23): 4767-78.
Abstract: The strategy of phospholipid-based biomimicry has been used to molecularly engineer poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based hydrogels for improved in vitro and potential in vivo biocompatibility. Two methacrylate-based monomers, poly(ethylene glycol) (200) monomethacrylate (PEGMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC), were incorporated at varying mole fractions of 0.0-0.5 mol% PEGMA and 0-10 mol% MPC respectively, into 3 mol% tetraethyleneglycol diacrylate (TEGDA) cross-linked p(HEMA) networks. Upon hydration of these engineered hydrogels, a reduction in receding contact angle from 22+/-1.2 degrees for p(HEMA) to 8+/-2.7 degrees for p(HEMA) containing 0.5:10 mol% PEGMA:MPC was observed, reflecting the significant increase in surface hydrophilicity with increasing PEGMA and MPC content upon prolonged hydration. Hydrogels containing MPC showed a temporal increase in hydrophilicity following continuous immersion in DI water over 5 days. Hydrogels containing 0.5 mol% PEGMA and MPC in the range of 5-10 mol% displayed reduced protein adsorption when incubated with the common extracellular matrix proteins; fibronectin, collagen or laminin, producing up to 64% less protein adsorption compared to p(HEMA). Compositional optima for cell viability and proliferation established from two-factor Central Composite design analysis of human muscle fibroblasts cultured on these hydrogels suggest that those containing PEGMA between 0.3 and 0.5 mol% and MPC levels around 5-10 mol% exhibit desirable characteristics for implant material coatings-high viability (>80%) with low proliferation (<40%), confirming a lack of cytotoxicity.
| Molecularly engineered PEG hydrogels: a novel model system for proteolytically mediated cell migration
Raeber, G. P., M. P. Lutolf, et al. (2005), Biophys J 89(2): 1374-88.
Abstract: Model systems mimicking the extracellular matrix (ECM) have greatly helped in quantifying cell migration in three dimensions and elucidated the molecular determinants of cellular motility in morphogenesis, regeneration, and disease progression. Here we tested the suitability of proteolytically degradable synthetic poly(ethylene glycol) (PEG)-based hydrogels as an ECM model system for cell migration research and compared this designer matrix with the two well-established ECM mimetics fibrin and collagen. Three-dimensional migration of dermal fibroblasts was quantified by time-lapse microscopy and automated single-cell tracking. A broadband matrix metalloproteinase (MMP) inhibitor and tumor necrosis factor-alpha, a potent MMP-inducer in fibroblasts, were used to alter MMP regulation. We demonstrate a high sensitivity of migration in synthetic networks to both MMP modulators: inhibition led to an almost complete suppression of migration in PEG hydrogels, whereas MMP upregulation increased the fraction of migrating cells significantly. Conversely, migration in collagen and fibrin proved to be less sensitive to the above MMP modulators, as their fibrillar architecture allowed for MMP-independent migration through preexisting pores. The possibility of molecularly recapitulating key functions of the natural extracellular microenvironment and the improved protease sensitivity makes PEG hydrogels an interesting model system that allows correlation between protease activity and cell migration.
| Molecularly imprinted bioartificial membranes for the selective recognition of biological molecules. Part 2: release of components and thermal analysis
Silvestri, D., C. Cristallini, et al. (2005), J Biomater Sci Polym Ed 16(3): 397-410.
Abstract: 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.
| Molecularly imprinted TiO2 thin film by liquid phase deposition for the determination of L-glutamic acid
Feng, L., Y. Liu, et al. (2004), Langmuir 20(5): 1786-90.
Abstract: For the first time, the feasibility of a molecularly imprinted liquid phase deposition (LPD) thin film has been demonstrated. Thin films of titanium oxide imprinted with L-glutamic acid were prepared by the LPD method on a gold-coated quartz crystal microbalance. The imprinted molecule could be removed upon treatment with immersion in deionized water. A sensor was developed on the basis of this method and showed good sensitivity, selectivity, and reproducibility to the template molecule. An equation was deduced to characterize the interaction between molecularly imprinted films and the template by virtue of Scatchard analysis. X-ray photoelectron spectroscopy was introduced to show the evidence for the molecular imprinting phenomenon. The linear relationship between the frequency shifts and the concentration of analyte in the range of 10-200 microM was obtained. LPD proves to be a powerful method for imprinting titanium oxide thin films.
| Monoclonal antibodies to type V collagen for immunohistological examination of new tissue deposition associated with biomaterial implants
Werkmeister, J. A. and J. A. Ramshaw (1991), J Histochem Cytochem 39(9): 1215-20.
Abstract: We developed a panel of highly specific monoclonal antibodies (MAb) against dog Type V collagen. Each antibody showed differential reactivities towards Type V collagen from other species. All the antibodies were highly reactive in conventional ELISA, as well as with electroblots of collagen after polyacrylamide gel electrophoresis using non-denaturing conditions. The MAb were shown to be suitable for the immunohistological detection of Type V collagen in tissue sections, although this normally required pre-treatment of sections with 50 mM acetic acid. In particular, the antibodies were shown to be useful for examining samples of a collagen-based biomaterial, a vascular prosthesis, after explant from evaluation in an animal model. This showed that Type V collagen was most prominent in regions of new tissue formation within the neointima, close to the inner surface of the prosthesis. The broad spectrum of differential reactivities allows the antibodies to be used for a wide range of experimental models. These MAb therefore provide a novel approach for the evaluation of biomaterial performance, particularly for collagen-based implants.
| Monoclonal antibodies to type VI collagen demonstrate new tissue augmentation of a collagen-based biomaterial implant
Werkmeister, J. A., T. A. Tebb, et al. (1993), J Histochem Cytochem 41(11): 1701-6.
Abstract: We developed a panel of highly specific monoclonal antibodies (MAb) to either human or dog collagen Type VI. Various degrees of species crossreactivities were found with ELISA and immunohistology. Because of these differentiating species specificities, which allowed distinction between the original donor collagen and newly formed host collagen, the MAb proved to be valuable tools in examination of explanted samples of an ovine composite vascular prosthesis retrieved from a canine model. With an MAb that reacts with dog but not sheep collagen Type VI, newly synthesized pockets of collagen Type VI could readily be detected within the prosthesis as early as 3 months after implantation. These areas were associated with regions of cell infiltration, presumably derived from the host. This association was also apparent in the newly formed intimal region of the prosthesis where only host cells were found. Another of the MAb, which was positive against human but not sheep collagen, was also used to demonstrate marked deposition of host collagen Type VI in a retrieved human sample of the prosthesis. In this case the antibody was able to detect collagen on a formalin-fixed tissue, which would broaden the scope of its use in clinical and pathological situations. Use of these novel antibody probes provides a rapid marker for new tissue augmentation of implanted biological devices which would be an indicator of the long-term performance of a prosthesis.
| Monocyte activation on polyelectrolyte multilayers
Hwang, J. J., S. Jelacic, et al. (2005), J Biomater Sci Polym Ed 16(2): 237-51.
Abstract: The adherence and activation of primary human monocytes was investigated on a polyelectrolyte multilayer film containing hyaluronic acid (HA) and poly-L-lysine (PLL). The sequential layer-by-layer deposition of the multilayer film was characterized by surface plasmon resonance. Eight alternating bilayers displayed an effective thickness of 16.15 nm with a total polymer coverage of 2.10 microg/cm2. For cell studies, HA-PLL multilayers were constructed on tissue culture polystyrene (TCPS) substrates and characterized by time of flight second ion mass spectrometry (ToF-SIMS) analysis. Principal component analysis of the ToF-SIMS spectra resolved no significant difference in surface chemistry between PLL-terminated and HA-terminated multilayer surfaces. Monocyte adhesion on PLL- and HA-terminated surfaces was measured by the lactate dehydrogenase assay and showed a significant decrease in cell adhesion after 24 h incubation. Cell viability measured by Live/Dead fluorescent staining showed significant cell death in the adherent cell population over these 24 h. Tumor necrosis factor-alpha (TNF-alpha) production, a measure of monocyte activation, was quantified by ELISA and normalized to the number of adherent monocytes. The activation of monocytes on PLL-terminated and HA-terminated surfaces was nearly identical, and both surfaces had TNF-alpha levels that were 8-fold higher than TCPS. These results demonstrate that sufficient PLL had diffused into the surface layer to direct monocyte adherence and to induce cytokine activation and cell death on the HA-terminated multilayer films. The diffusion of the second multilayer component to the coating surface should, thus, be taken into account in the design of polyelectrolyte-based biomaterial coating strategies.
| Monocyte viability on titanium and copper coated titanium
Suska, F., C. Gretzer, et al. (2005), Biomaterials 26(30): 5942-50.
Abstract: The role of apoptosis/cell death in the inflammatory response at the implanted materials is unexplored. Two surfaces with different cytotoxic potential and in vivo outcomes, titanium (Ti) and copper (Cu) were incubated in vitro with human monocytes and studied using a method to discriminate apoptotic and necrotic cells (Annexin V/PI staining). Further, staurosporine, a potent inducer of apoptosis, was added to the surface adherent monocytes. Lactate dehydrogenase (a marker of cell membrane injury) and TNF-alpha and IL-10, cytokines, previously suggested to play a major role in the monocyte apoptosis, were assayed in the culture medium. The results demonstrated that Ti surfaces displayed enhanced monocyte survival and production of IL-10 and TNF-alpha. Cu adherent cells exhibited apoptotic signs as early as 1h after incubation. In contrast to Ti, after 48 h the predominance of apoptotic cells switched to apoptotic/necrotic cells on Cu surfaces. Staurosporine treatment of Ti adherent cells mediated similar type of cell death. LDH and cytokine contents were low around Cu surfaces, partly explained by interference between Cu ions and LDH and cytokines. This study suggests that material properties rapidly influence the onset of human monocyte apoptosis and progression to late apoptosis/necrosis. Early detection of apoptosis and cell death may be important for the understanding of the biological response to implanted materials.
| Monocyte-biomaterial interaction inducing phenotypic dynamics of monocytes: a possible role of monocyte subsets in biocompatibility
Bhardwaj, R. S., U. Henze, et al. (1997), J Mater Sci Mater Med 8(12): 737-42.
Abstract: For the in vitro study of cell-biomaterial surface interactions, the choice of cell type is crucial. In vivo data indicate that during the healing of the implant in the tissues, the pivotal cell types are the macrophages. These cells, upon interaction with any foreign material, might initiate a spectrum of responses, which could lead to acute and chronic inflammatory changes affecting the biocompatibility of the implant. Whether the mechanisms governing the type of evolving inflammatory reaction could be attributed to the macrophages functional differentiation mirrored by monocyte subsets during the polymer interaction, is poorly described. This in vitro study, therefore, attempted to investigate whether different biomaterials influence monocyte cellular activity, determined by the myeloperoxidase level and mitochondrial XTT cleavage, and phenotype dynamics characterized by the presence of CD14, RM 3/1 and 27E10 antigens. It is shown that different polymers exert differential potential to influence monocytes, both in their cellular activity and their phenotypic pattern. Thus, these findings demonstrating material-induced monocyte activation and monocyte phenotype modulation, are suggestive of the monocyte role as reporter cells in evaluating the biocompatibility of a synthetic medical device.
| Monolayer-derivative functionalization of non-oxidized silicon surfaces
Shirahata, N., A. Hozumi, et al. (2005), Chem Rec 5(3): 145-59.
Abstract: This article describes a variety of monolayers anchored directly onto silicon surfaces without an oxide interlayer, their formation mechanisms, their technological applications, and our personal views on the future prospects for this field. The chemical modification of non-oxidized silicon surfaces utilizing monolayers was first reported in 1993. The basic finding that a non-oxidized silicon surface could be neutralized with alkyl chains through direct covalent linkage, i.e., silicon-carbon, has offered chemical scientists ease of handling even in an ambient environment and, thus, research has been predictably focused on forming anti-stiction coating films for nano- and micro-electromechanical systems (NEMS/MEMS). Such surface reforming has also been achieved by using other monolayers, which form interfacial bonds, e.g., silicon-nitrogen and silicon-oxygen. The resultant monolayer surfaces are useful for silicon-based applications including molecular electron transfer films, monolayer templates, molecular insulators, capsulators, and bioderivatives. Such monolayers are applicable not only for surface modification, but also for manipulating individual nanomaterials. By modifying the terminal groups of monolayers with nanomaterials including nanocrystals and biomolecules, the nanomaterials can remarkably be immobilized directly onto non-oxidized silicon surfaces based on the formation mechanisms of the monolayer. Such immobilizations will revolutionize the analysis of the specific features and capabilities of individual nanomaterials. Furthermore, the path will be opened for the development of more advanced monolayer-derived chip technology. To achieve this goal, it is extremely important to thoroughly understand the functionalization processes on silicon, since the resultant internal structures and properties of monolayer-derivative silicon may strongly depend on their course of formation.
| Morphogenesis and tissue engineering of bone and cartilage: inductive signals, stem cells, and biomimetic biomaterials
Reddi, A. H. (2000), Tissue Eng 6(4): 351-9.
Abstract: Morphogenesis is the developmental cascade of pattern formation, body plan establishment, and the architecture of mirror-image bilateral symmetry of many structures and asymmetry of some, culminating in the adult form. Tissue engineering is the emerging discipline of design and construction of spare parts for the human body to restore function based on principles of molecular developmental biology and morphogenesis governed by bioengineering. The three key ingredients for both morphogenesis and tissue engineering are inductive signals, responding stem cells, and the extracellular matrix. Among the many tissues in the human body, bone has considerable powers for regeneration and is a prototype model for tissue engineering based on morphogenesis. Implantation of demineralized bone matrix into subcutaneous sites results in local bone induction. This model mimics sequential limb morphogenesis and permitted the isolation of bone morphogens. Although it is traditional to study morphogenetic signals in embryos, bone morphogenetic proteins (BMPs), the inductive signals for bone, were isolated from demineralized bone matrix from adults. BMPs and related cartilage-derived morphogenetic proteins (CDMPs) initiate, promote, and maintain chondrogenesis and osteogenesis and have actions beyond bone. The symbiosis of bone inductive and conductive strategies are critical for tissue engineering, and is in turn governed by the context and biomechanics. The context is the microenvironment, consisting of extracellular matrix, which can be duplicated by biomimetic biomaterials such as collagens, hydroxyapatite, proteoglycans, and cell adhesion proteins including fibronectins. Thus, the rules of architecture for tissue engineering are an imitation of the laws of developmental biology and morphogenesis, and thus may be universal for all tissues, including bones and joints.
| Morphologic characteristics of adsorbed human plasma proteins on vascular grafts and biomaterials
Pankowsky, D. A., N. P. Ziats, et al. (1990), J Vasc Surg 11(4): 599-606.
Abstract: Protein adsorption on the surfaces of clinically significant prosthetic vascular graft materials from human whole blood was independent of plasma concentration as determined morphologically by use of immunogold labels. Some proteins, such as fibrinogen, adsorbed in a multilayer pattern on expanded polytetrafluoroethylene and had a preference for particular surface features of the polymer. Other proteins, such as Hageman factor (factor XII), showed diffuse adsorption patterns. Physiologically significant proteins that have not been well studied, such as immunoglobulin G and factor VIII, adsorbed readily to the surface of expanded polytetrafluoroethylene. This finding may be significant since adsorbed proteins may activate coagulation mechanisms and immunologic responses, including platelet and monocyte adhesion and activation. Any human blood protein for which an antibody has been developed can be studied by use of this technique.
| Morphological and biochemical modifications of human macrophages treated with various biomaterials
Carr, S., W. Johnston, et al. (1999), Biomed Sci Instrum 35: 211-6.
Abstract: Although tissue culture techniques are used extensively to explore the biocompatibility of various biomaterials used in orthopaedic, dental and pharmaceutical fields, the role of these materials towards human monocytes/macrophages has not been fully elucidated. The specific objectives of this investigation were: (1) to determine the biochemical markers resulting from exposure of the human monocytes/macrophages to titanium (TI), large size polyethylene (LSP), submicron polyethylene (SPE), hydroxyapatite (HA), large particle size tricalcium phosphate (LTCP), and small particle size tricalcium phosphate (STCP), and (2) to morphologically evaluate the viability of the cells treated with the aforementioned biomaterials. Approximately 15 volunteers donated blood for each phase (24, 48, and 72 hours) of the experiment. The monocytes were isolated by following established lab procedures (Histopaque 1077 and 1119). Aseptic techniques were followed throughout each phase. Each phase contained four experimental groups (TI, LSP, SPE, HA). Each group was comprised of six wells. The total protein, catalase, LDH, MDA, and cell count were measured using established lab protocols. Data obtained suggests that: (I) regardless of the biomaterial being used all experimental groups experienced remarkable phagocytosis in the first two phases (24, 48 hours), (II) during the 24 hour phase MDA activities were increased in TI, LTCP, and STCP treated wells when compared to the control and other experimental groups, (III) in the 48 hour phase the MDA level increased in LPE and STCP treated cells, (IV) there were significant differences in LDH levels in LPE, STCP, and SPE at 24 hours compared to the control and other experimental groups, (V) LDH activities were increased in LPE, STCP, SPE, and LTCP at 48 hours, and (VI) at 72 hours there were significant increases in catalase activity in HA, TI, SPE and LPE when compared to the control group and other experimental groups. Information obtained from this study provided new ideas about the interrelationship of various biomaterials, the effect of size and cell response to the various biomaterials.
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