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| 2. |
- Hook, F.F, et al.
(författare)
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A comparative study of protein adsorption on titanium oxide surfaces using in situ ellipsometry, optical waveguide lightmode spectroscopy, and quartz crystal microbalance/dissipation
- 2002
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Ingår i: Colloids and Surfaces B. - 0927-7765 .- 1873-4367. ; 24:2, s. 155-170
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption kinetics of three model proteins - human serum albumin, fibrinogen and hemoglobin - has been measured and compared using three different experimental techniques: optical waveguide lightmode spectroscopy (OWLS), ellipsometry (ELM) and quartz crystal microbalance (QCM-D). The studies were complemented by also monitoring the corresponding antibody interactions with the pre-adsorbed protein layer. All measurements were performed with identically prepared titanium oxide coated substrates. All three techniques are suitable to follow in-situ kinetics of protein-surface and protein-antibody interactions, and provide quantitative values of the adsorbed adlayer mass. The results have, however, different physical contents. The optical techniques OWLS and ELM provide in most cases consistent and comparable results, which can be straightforwardly converted to adsorbed protein molar ('dry') mass. QCM-D, on the other hand, produces measured values that are generally higher in terms of mass. This, in turn, provides valuable, complementary information in two respects: (i) the mass calculated from the resonance frequency shift includes both protein mass and water that binds or hydrodynamically couples to the protein adlayer, and (ii) analysis of the energy dissipation in the adlayer and its magnitude in relation to the frequency shift (c.f. adsorbed mass) provides insight about the mechanical/structural properties such as viscoelasticity. © 2002 Elsevier Science B.V. All rights reserved.
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- Tosatti, S., et al.
(författare)
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Peptide functionalized poly(L-lysine)-g-poly(ethylene glycol) on titanium : Resistance to protein adsorption in full heparinized human blood plasma
- 2003
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Ingår i: Biomaterials. - 0142-9612 .- 1878-5905. ; 24:27, s. 4949-4958
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Tidskriftsartikel (refereegranskat)abstract
- The graft copolymer poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) and its RGD- and RDG-functionalized derivatives (PLL-g-PEG/PEG-peptide) were assembled from aqueous solutions on titanium (oxide) surfaces. The polymers were characterized by NMR in order to determine quantitatively the grafting ratio, g (Lys monomer units/PEG side chains), and the fraction of the PEG side chains carrying the terminal peptide group. The titanium surfaces modified with the polymeric monomolecular adlayers were exposed to full heparinized blood plasma. The adsorbed masses were measured by in situ ellipsometry. The different PLL-g-PEG-coated surfaces showed, within the detection limit of the ellipsometric technique, no statistically significant protein adsorption during exposure to plasma for 30min at 22°C or 37°C, whereas clean, uncoated titanium surfaces adsorbed approximately 350ng/cm2 of plasma proteins. The high degree of resistance of the PEGylated surface to non-specific adsorption makes peptide-modified PLL-g-PEG a useful candidate for the surface modification of biomedical devices such as implants that are capable of eliciting specific interactions with integrin-type cell receptors even in the presence of full blood plasma. The results refer to short-term blood plasma exposure that cannot be extrapolated a priori to long-term clinical performance. © 2003 Elsevier Ltd. All rights reserved.
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| 5. |
- Brunette, Donald M, et al.
(författare)
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Titanium in Medicine : material science, surface science, engineering, biological responses and medical applications
- 2001
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This comprehensive book provides state-of-the-art scientific and technical information in a clear format and consistent structure making it suitable for formal course work or self-instruction. The authors are drawn not only from academic institutions but also from industry, so that practical aspects of implant fabrication and material handling are covered that are often lacking in biomaterials texts. Besides readers with a general interest in biomaterials, the book will interest materials investigators, surgeons and dentists using titanium implants, medical scientists and engineers, as well as lecturers at universities or institutes who would benefit by having ready access to authoritative information on the use of titanium for implants, devices and instruments. More information: http://www.titaniuminmedicine.com.
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| 6. |
- Faraasen, S, et al.
(författare)
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Ligand-specific targeting of microspheres to phagocytes by surface modification with poly(L-lysine)-grafted poly(ethylene glycol) conjugate
- 2003
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Ingår i: Pharmaceutical research. - 0724-8741 .- 1573-904X. ; 20:2, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. The purpose of this study was to demonstrate specific receptor- mediated targeting of phagocytes by functional surface coatings of microparticles, shielding from nonspecific phagocytosis and allowing ligand- specific interactions via molecular recognition. Methods. Coatings of the comb polymer poly( L- lysine)- g-poly( ethylene glycol) (PLL- g- PEG) were investigated for potential to inhibit 1) nonspecific spreading of human blood- derived macrophages (MOs) and dendritic cells (DCs) on glass and 2) nonspecific phagocytosis of PLL- g- PEG- coated, carboxylated polystyrene (PS) or biodegradable poly( D, L- lactide- co- glycolide) (PLGA) microspheres. Coating was performed by adsorption of positively charged PLL- g- PEG on negatively charged microparticles or plasma- cleaned glass through electrostatic interaction. The feasibility of ligand-specific interactions was tested with a model ligand, RGD, conjugated to PEG chains of PLL- g- PEG to form PLL- g- PEG- RGD and compared with inactive ligand conjugate, PLL- g- PEG- RDG. Results. Coatings with PLL- g- PEG largely impaired the adherence and spreading of MOs and DCs on glass. The repellent character of PLL- g- PEG coatings drastically reduced phagocytosis of coated PS and PLGA microparticles to 10% in presence of serum. With both MOs and DCs, we observed ligand- specific interactions with PLL- g-PEG- RGD coatings on glass and PS and PLGA microspheres. Ligand specificity was abolished when using inactive ligand conjugate PLL- g- PEG- RDG, whereas repellency of coating was maintained. Conclusions. Coatings of PLL- g- PEG- ligand conjugates provide a novel technology for ligand specific targeting of microspheres to MOs and DCs while reducing nonspecific phagocytosis.
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