Surface modification for controlled studies of cell–ligand interactions

Neff, J. A.; Tresco, Patrick A.; Caldwell, Karin D.

doi:10.1016/s0142-9612(99)00166-0

Cited by 198 publications

(166 citation statements)

References 49 publications

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“…Overall, the present findings parallel those of many other systems used to present cellular adhesion ligands to cells and probe the effect of ligand types and bulk densities on cell phenotype. 10,11,18,22,23 It was striking that, in certain experiments, the initial spreading of MC3T3 cells was significantly enhanced as the RGD island spacing increased but the growth rate of the cells was unexpectedly suppressed in parallel (Figure 4). These effects were decoupled from the bulk ligand density in the gel ( Figure 5A).…”

Section: Discussionmentioning

confidence: 96%

Nanoscale Adhesion Ligand Organization Regulates Osteoblast Proliferation and Differentiation

et al. 2004

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It was hypothesized that nanoscale adhesion ligand spacing regulates cell adhesion, proliferation, and differentiation, and that this control can be decoupled from the overall ligand density. Alginate was chemically modified with a peptide containing the cell adhesion sequence arginineglycine-aspartic acid (RGD), and the nanoscale spacing of RGD ligands in alginate gels was varied. A decrease in the RGD island spacing from 78 to 36 nm upregulated the proliferation rates of MC3T3-E1 cells from 0.59 ± 0.08 to 0.73 ± 0.03 day −1 and resulted in 4-fold increase of the osteocalcin secretion rate. This finding was independent of the bulk ligand density of gels. These results indicate that nanoscale ligand organization may provide an important variable to regulate cell functions in many biomedical applications, including tissue engineering.

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Section: Discussionmentioning

confidence: 96%

Nanoscale Adhesion Ligand Organization Regulates Osteoblast Proliferation and Differentiation

et al. 2004

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“…Langer et al modified the surface of poly(glycerol-co-sebacic acid) membranes with peptides containing an RGD ligand sequence to improve the attachment of photoreceptor layers in the retina [6]. Neff et al modified polystyrene surfaces with GRGDSY (i.e., a cell adhesion motif) using a PEO/PPO/PEO triblock copolymer spacer [7,8]. The results indicated that cell adhesion and subsequent spreading was improved significantly.…”

Section: Introductionmentioning

confidence: 99%

Gelatin Functionalization of Biomaterial Surfaces: Strategies for Immobilization and Visualization

et al. 2011

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Abstract:In the present work, the immobilization of gelatin as biopolymer on two types of implantable biomaterials, polyimide and titanium, was compared. Both materials are known for their biocompatibility while lacking cell-interactive behavior. For both materials, a pre-functionalization step was required to enable gelatin immobilization. For the polyimide foils, a reactive succinimidyl ester was introduced first on the surface, followed by covalent grafting of gelatin. For the titanium material, methacrylate groups were first introduced on the Ti surface through a silanization reaction. The applied functionalities enabled the subsequent immobilization of methacrylamide modified gelatin. Both surface modified materials were characterized in depth using atomic force microscopy, static contact angle measurements, confocal fluorescence microscopy, attenuated total reflection infrared spectroscopy and X-ray photo-electron spectroscopy. The results indicated that the strategies elaborated for both material classes are suitable to apply stable gelatin coatings. Interestingly, depending on the material class studied, not all surface analysis techniques are applicable.

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“…This is however in the range of previously detected ligand spacing using fibroblasts on RGD functionalized hydrogels. 18,20 Other studies on ultraflat films on hard substrates revealed different RGD spacing optimal for adhesion and spreading. 36,38,39 This underlines the importance of critical assessment of the amount of ligands needed for cell adhesion for each system, and the special properties of hydrogel films where obviously a higher ligand density is needed for cell adhesion than on ultraflat coatings.…”

Section: -9 Beermentioning

confidence: 99%

“…Multiple quantification methods such as radiolabeling, [18][19][20] x-ray photoelectron spectrometry (XPS), 21 time-offlight secondary ion mass spectroscopy (ToF-SIMS), 20,22,23 enzyme linked immunosorbent assay (ELISA), 24 quartz crystal microbalance (QCM), 25 ellipsometry, 19 surface plasmon resonance (SPR), 10,19 total internal reflection fluorescence (TIRF), 19 and attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) (Ref. 24) have been used to quantify ligand density on biomaterial surfaces.…”

Section: Introductionmentioning

confidence: 99%

Quantifying ligand–cell interactions and determination of the surface concentrations of ligands on hydrogel films: The measurement challenge

et al. 2015

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Hydrogels are extensively studied for biomaterials application as they provide water swollen noninteracting matrices in which specific binding motifs and enzyme-sensitive degradation sites can be incorporated to tailor cell adhesion, proliferation, and migration. Hydrogels also serve as excellent basis for surface modification of biomaterials where interfacial characteristics are decisive for implant success or failure. However, the three-dimensional nature of hydrogels makes it hard to distinguish between the bioactive ligand density at the hydrogel-cell interface that is able to interact with cells and the ligands that are immobilized inside the hydrogel and not accessible for cells. Here, the authors compare x-ray photoelectron spectrometry (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), enzyme linked immunosorbent assay (ELISA), and the correlation with quantitative cell adhesion using primary human dermal fibroblasts (HDF) to gain insight into ligand distribution. The authors show that although XPS provides the most useful quantitative analysis, it lacks the sensitivity to measure biologically meaningful concentrations of ligands. However, ToF-SIMS is able to access this range provided that there are clearly distinguishable secondary ions and a calibration method is found. Detection by ELISA appears to be sensitive to the ligand density on the surface that is necessary to mediate cell adhesion, but the upper limit of detection coincides closely with the minimal ligand spacing required to support cell proliferation. Radioactive measurements and ELISAs were performed on amine reactive well plates as true 2D surfaces to estimate the ligand density necessary to allow cell adhesion onto hydrogel films. Optimal ligand spacing for HDF adhesion and proliferation on ultrathin hydrogel films was determined as 6.5 ± 1.5 nm.

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Surface modification for controlled studies of cell–ligand interactions

Cited by 198 publications

References 49 publications

Nanoscale Adhesion Ligand Organization Regulates Osteoblast Proliferation and Differentiation

Nanoscale Adhesion Ligand Organization Regulates Osteoblast Proliferation and Differentiation

Gelatin Functionalization of Biomaterial Surfaces: Strategies for Immobilization and Visualization

Quantifying ligand–cell interactions and determination of the surface concentrations of ligands on hydrogel films: The measurement challenge

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