Cell Adhesion Experiments Research Articles

Deposition of nonfouling plasma polymers to a thermoplastic silicone elastomer for microfluidic and biomedical applications

ABSTRACTPlasma polymerization is used for the modification and control of surface properties of a highly transparent, thermoplastic elastomeric silicone copolymer, GENIOMER® 80 (G80). PEG‐like diglyme plasma polymer films were deposited with ether retentions varying between 20% and 70% as measured by X‐ray photoelectron spectroscopy analysis which did not affect the transparency of the substrate. Films with ether retentions of greater than 70% inhibit protein binding (bovine serum albumin and fibrinogen) and cell proliferation. A short oxygen plasma pretreatment enhances the adhesion and stability of the film as shown by protein binding and cell adhesion experiments. The transparency of the material and the stability of the coating makes this material a versatile bulk material for technical (e.g., lab‐on‐a‐chip) and biomedical (e.g., intraocular lens) applications. The G80/plasma polymer composite is stable against vigorous washing and storage over 5 months and, therefore, offers an attractive alternative to poly(dimethylsiloxane). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40500.

Galectin-7 acts as an adhesion molecule during implantation and increased expression is associated with miscarriage

IntroductionGalectins are expressed at the fetal–maternal interface and have multiple roles including during blastocyst implantation. The expression of galectin-7 however has not been investigated in the uterus. We aimed to localise galectin-7 to the endometrium of women with normal fertility and with a history of miscarriage and prospectively determine whether serum levels are altered in women who subsequently miscarry. We also investigated the role of galectin-7 on trophoblast–endometrial epithelial cell adhesion. MethodsImmunohistochemistry localised galectin-7 to endometrium throughout the menstrual cycle in women (normal fertility or with history of miscarriage) and in first trimester implantation sites. Galectin-7 serum levels were determined by ELISA. We used both endometrial epithelial–trophoblast cell lines and primary cells for cell–cell adhesion experiments. ResultsGalectin-7 immunolocalized to endometrial luminal and glandular epithelium in normally fertile women and was upregulated in epithelium and stroma of women with a history of miscarriage. Similarly, gelectin-7 serum levels were elevated at 6 weeks gestation in women who subsequently miscarried compared to gestation matched controls. Exogenous galectin-7 reduced endometrial epithelial–trophoblast adhesion in cell-line and primary cell assays. However, when endometrial epithelial cells were isolated from women with endometrial disorders, galectin-7 increased epithelial–trophoblast adhesion. ConclusionsGalectin-7 is produced by endometrial epithelium and is abnormally elevated in the endometrium of women with a history of miscarriage. Serum levels may be useful as a predictive biomarker of miscarriage. Our data suggests that galectin-7 facilitates adhesion of the embryo to the endometrium and elevated galectin-7 may result in abnormal adhesion.

Corrosion Behaviors and Biocompatibility of the Ni-Cr-Mo Dental Casting Alloy

The purpose of this research is to make new alloys and evaluate their corrosion behavior and biocompatibility by adding different amounts of Mo to Ni-Cr alloys (Ni-13Cr-4Mo, Ni-13Cr-6Mo, Ni-13Cr-8Mo, and Ni-13Cr-10Mo). In this research, we used incubated 6th passage human gingival fibroblast cells for the cell viability and cell adhesion experiments. The form and amount of adhesion of human gingival fibroblast cells to alloys were observed using field emission scanning electron microscopy (FE-SEM). In order to evaluate quantitative analysis of cell adhesion and corrosion behaviors, we used the AC impedance method (at 37 ± 1 ℃ in 0.9% NaCl solution) and compared the obtained results with the results of the FE-SEM. The microstructure of the Ni-13Cr-6Mo alloy had a more uniform surface than the other alloys. The Ni-13Cr-6Mo alloy demonstrated the lowest cytotoxicity in the cell viability assay, and the highest cell adhesion and corrosion resistance in an AC impedance test. We concluded that Ni-Cr-xMo alloys have better cell viability and cell adhesion and higher electrochemical impedance than Ni-Cr alloys.

Hidden Markov Models With Applications in Cell Adhesion Experiments

Estimation of the number of hidden states is challenging in hidden Markov models. Motivated by the analysis of a specific type of cell adhesion experiments, a new framework based on a hidden Markov model and double penalized order selection is proposed. The order selection procedure is shown to be consistent in estimating the number of states. A modified expectation–maximization algorithm is introduced to efficiently estimate parameters in the model. Simulations show that the proposed framework outperforms existing methods. Applications of the proposed methodology to real data demonstrate the accuracy of estimating receptor–ligand bond lifetimes and waiting times which are essential in kinetic parameter estimation. Supplementary materials for this article are available online.

Potential Use of Porous Titanium–Niobium Alloy in Orthopedic Implants: Preparation and Experimental Study of Its Biocompatibility In Vitro

BackgroundThe improvement of bone ingrowth into prosthesis and enhancement of the combination of the range between the bone and prosthesis are important for long-term stability of artificial joints. They are the focus of research on uncemented artificial joints. Porous materials can be of potential use to solve these problems.Objectives/PurposesThis research aims to observe the characteristics of the new porous Ti-25Nb alloy and its biocompatibility in vitro, and to provide basic experimental evidence for the development of new porous prostheses or bone implants for bone tissue regeneration.MethodsThe Ti-25Nb alloys with different porosities were fabricated using powder metallurgy. The alloys were then evaluated based on several characteristics, such as mechanical properties, purity, pore size, and porosity. To evaluate biocompatibility, the specimens were subjected to methylthiazol tetrazolium (MTT) colorimetric assay, cell adhesion and proliferation assay using acridine staining, scanning electron microscopy, and detection of inflammation factor interleukin-6 (IL-6).ResultsThe porous Ti-25Nb alloy with interconnected pores had a pore size of 200 µm to 500 µm, which was favorable for bone ingrowth. The compressive strength of the alloy was similar to that of cortical bone, while with the elastic modulus closer to cancellous bone. MTT assay showed that the alloy had no adverse reaction to rabbit bone marrow mesenchymal stem cells, with a toxicity level of 0 to 1. Cell adhesion and proliferation experiments showed excellent cell growth on the surface and inside the pores of the alloy. According to the IL-6 levels, the alloy did not cause any obvious inflammatory response.ConclusionAll porous Ti-25Nb alloys showed good biocompatibility regardless of the percentage of porosity. The basic requirement of clinical orthopedic implants was satisfied, which made the alloy a good prospect for biomedical application. The alloy with 70% porosity had the optimum mechanical properties, as well as suitable pore size and porosity, which allowed more bone ingrowth.

Effect of ribosomal protein S6 kinase 4 gene over-expression on biological behaviors of MDA-MB-231 cells

Objective To observe the effect of ribosomal protein S6 kinase 4 gene (RSK4) gene over-expression on biological behaviors of MDA-MB-231 cells.Methods Cell colony test and cell counting kit-8 (CCK-8) test were applied to observe the proliferation.Cell scratch test and Transwell assay were used to observe the invasion and migration.Cell adhesion assay was used to observe the adhesion.Results After the stable transfection of RSK4 over-expression lentiviral vector,cell scratch test demonstrated that the migration ability in experimental group was significantly decreased.Cell colony test showed that the cell colony formation rate in experimental group was significantly lower than in blank group and negative group.The average cell colony formation rate in experimental group,blank group and negative group was (21.280 ±0.114) ％,(9.150 ± 0.120) ％ and (19.080 ± 0.108) ％ respectively.Transwell assay revealed that the number of cells passing through the Transwell filtration membrane in experimental group was significantly less than in blank group and control group.The migration result of the experimental group is 273.000 ± 2.293,while the invasion results of group Con2 is 89.000 ± 1.208.CCK-8 test shows that the absorbance of group OE in 24 h,48 h,72 h and 96 h is 0.1790 ± 0.0044,0.2090 ± 0.0218,0.2230 ± 0.0117 and 0.2680 ± 0.0274,all results of the experimental group are lower than those other groups,whose differences are statistically significant (P ＜ 0.05).Cell adhesion experiment shows that the cell adhesion of the experimental group after inoculated 3 h and 6 h are (0.0700 ± 0.0037) ％,(0.1920 ± 0.0133) ％,and the result is significantly higher than other groups,whose difference is statistically significant (P ＜ 0.05).Conclusion After the over expression of RSK4 gene,the biological behavior of MDA-MB-231 cell were effectively suppressed. Key words: Ribosomal protein S6 kinase 4; Breast cancer; Biological characteristics; Suppress

The IgCAMs CAR, BT-IgSF, and CLMP: structure, function, and diseases.

The coxsackie-adenovirus receptor (CAR) is the prototype of a small subfamily of IgCAMs composed of CAR itself, CLMP, BT-IgSF, ESAM, CTX, and A33. These six proteins are composed of one V-set and one C2-set Ig domains and a single transmembrane helix followed by a cytoplasmic stretch. They are localized in several tissues and organs and--except for ESAM, CTX, and A33--are expressed in the developing brain. CAR becomes downregulated at early postnatal stages and is absent from the adult brain. CAR, CLMP, and BT-IgSF mediate homotypic aggregation. Interestingly, cell adhesion experiments, binding studies, and crystallographic investigations on the extracellular domain reveal a flexible ectodomain for CAR that mediates homophilic and heterophilic binding. CAR has been extensively investigated in the context of gene therapy and diseases, while research on BT-IgSF and CLMP is at an early stage. Several mouse models as well as studies on patient tissues revealed an essential role for CAR in (1) the development of cardiac, renal, lymphatic, and intestinal tissue; (2) muscle pathology, remodeling, and regeneration; (3) tumor genesis/suppression and metastatic progression; and (4) in virus-mediated infections and gene therapy. Although the in vivo function of CAR in the brain has not been solved its developmentally regulated expression pattern in the brain as well as its function as CAM suggests that CAR might be implicated in neuronal network formation.

Characterization of the Quorum Sensing Regulon in <i>Acidithiobacillus ferrooxidans</i>

Bioleaching is the solubilization of metals from ores by microorganisms. This process is more efficient than conventional methods in the metal recovery from low grade ores while decreasing the operating cost and the environmental impact. Among the bioleaching bacteria, the Gram-negative chemolithoautotrophic acidophilic Acidithiobacillus ferrooxidans has the ability to adhere to mineral surface and to form biofilm. The genes involved in the production of this biofilm are controlled by a cellular communication system called Quorum Sensing (QS). The QS occurs mainly through the production of acyl homoserine lactones (AHLs). A functional QS system has been identified in At. ferrooxidans with an acyl synthase (AfeI) and a transcriptional regulator (AfeR). Here, our purpose is to characterize the quorum sensing regulon and particularly the genes involved in biofilm formation in At. ferrooxidans. This has been done by cell adhesion experiments comparing At. ferrooxidans grown with or without Tetrazol, an AHL analogue that activates the cell adhesion to mineral surface. The second step has been to compare the expression of some genes predicted to be involved in the QS regulon in At. ferrooxidans grown in the presence/absence of Tetrazol using real-time PCR. These two different strategies are expected to give insight on the moment at which the At. ferrooxidans QS regulon is switched on. The formation of biofilm could improve the bioleaching operation and therefore the understanding of the QS regulon is of primordial importance.

The enhanced effect of surface microstructured porous titanium on adhesion and osteoblastic differentiation of mesenchymal stem cells

Porous titanium with appropriate surface treatments can be osteoinductive. To investigate the effect of surface treatments of porous titanium on the attachment and differentiation of mesenchymal stem cells (MSCs), two kinds of surface microstructured porous titaniums, H₂O₂/TaCl₅ treated one (HTPT), and H₂O₂/TaCl₅ and subsequent simulated body fluid (SBF) treated one (STPT) were fabricated, and non-treated one (NTPT) was used as control. The morphology, specific surface area (SSA), pore distribution and mechanical strength of these materials were characterized respectively, and the results showed that H₂O₂/TaCl₅ treatment led to a significant increase in both SSA and micropores of HTPT, and the further SBF immersion resulted in the formation of a layer of bone-like apatite on the surface of STPT. Although the surface treatments had a little negative impact on the compressive strength and elasticity modulus of porous titanium, the mechanical strength of HTPT or STPT was enough for the bone defect repair of the load-bearing sites. The protein adsorption and cell adhesion experiments confirmed that the microstructured surface notably enhanced porous titanium's protein binding capacity and promoted MSCs adhesion on the surface. More importantly, cell differentiation experiments proved that the microstructured surface evidently elevated the osteoblastic gene expressions of MSCs compared to NTPT. The enhanced biological effect by the surface treatments was more robust on STPT. Therefore, our results suggest that the microstructured surface has great potential for promoting MSCs differentiation towards osteoblasts, giving excellent support for the osteoinduction of porous titanium with appropriate surface treatments.

Surface modification on polyethylene terephthalate films with 2-methacryloyloxyethyl phosphorylcholine

In this study, the surface of polyethylene terephthalate (PET) was modified to improve the protein and cell adhesion behavior with low temperature ammonia plasma treatment followed by 2-methacryloyloxyethyl phosphorylcholine (MPC) grafting. The x-ray photoelectron spectroscopy (XPS) results showed that the COO−, NCO and POH groups were successfully incorporated onto the sample surface after MPC grafting. Furthermore, formation of new bonds, N and NH on the sample surface grafted with MPC was recorded by Fourier transform infrared spectroscopy (FTIR). A large number of spherical particles at submicron to nanometer scale were also observed on the surface by atomic force microscopy (AFM). The cell adhesion experiments on PET film surfaces were evaluated and the highly hydrophilic surfaces could not promote cell adhesion and spreading. All results achieved in this study have clearly indicated that the method combining low temperature ammonia plasma treatment and MPC grafting is an effective way of producing a suitably hydrophilic PET surface with the capability of weakening the protein adsorption greatly.

Biselectivity of isoDGR Peptides for Fibronectin Binding Integrin Subtypes α5β1 and αvβ6: Conformational Control through Flanking Amino Acids

Integrins are the major class of cell adhesion proteins. Their interaction with different ligands of the extracellular matrix is diverse. To get more insight into these interactions, artificial ligands endowed with a well-defined activity/selectivity profile are necessary. Herein, we present a library of cyclic pentapeptides, based on our previously reported peptide motif c(-phg-isoDGR-X-), in which high activity toward fibronectin binding integrins α5β1 and αvβ6 and not on vitronectin binding integrins αvβ3 and αvβ5 has been achieved by changing the flanking amino acids. The structure of the most promising candidates has been determined using a combined approach of NMR, distance geometry, and molecular dynamics simulations, and docking studies have been further used to elucidate the peptide-integrin interactions at the molecular level. The peptides' binding affinity has been characterized by enzyme linked immunosorbent assay experiments, and the results have been verified by cell adhesion experiments on specifically functionalized surfaces.

Determination of the binding epitope of RGD-peptidomimetics to αvβ3 and αIIbβ3 integrin-rich intact cells by NMR and computational studies

NMR experiments (transferred NOE and Saturation Transfer Difference) were used to shed light on the binding epitope of RGD peptidomimetics 1-3 with integrins αvβ3 and α(IIb)β3, expressed on the membrane of ECV304 bladder cancer cells and human platelets, respectively. The NMR results were supported by docking calculations of 1-3 in the active sites of αvβ3 and α(IIb)β3 integrin receptors and were compared to the results of competitive αvβ3 receptor binding assays and competitive ECV304 cell adhesion experiments. While cis RGD ligand 1 interacts mainly with the α integrin subunit through its basic guanidine group, trans RGD ligands 2 and 3 are able to interact with both the α and β integrin subunits via an electrostatic clamp.

Order selection in nonlinear time series models with application to the study of cell memory

Cell adhesion experiments are biomechanical experiments studying the binding of a cell to another cell at the level of single molecules. Such a study plays an important role in tumor metastasis in cancer study. Motivated by analyzing a repeated cell adhesion experiment, a new class of nonlinear time series models with an order selection procedure is developed in this paper. Due to the nonlinearity, there are two types of overfitting. Therefore, a double penalized approach is introduced for order selection. To implement this approach, a global optimization algorithm using mixed integer programming is discussed. The procedure is shown to be asymptotically consistent in estimating both the order and parameters of the proposed model. Simulations show that the new order selection approach outperforms standard methods. The finite-sample performance of the estimator is also examined via a simulation study. The application of the proposed methodology to a T-cell experiment provides a better understanding of the kinetics and mechanics of cell adhesion, including quantifying the memory effect on a repeated unbinding force experiment and identifying the order of the memory.

Poly(N-vinylpyrrolidone)-modified poly(dimethylsiloxane) elastomers as anti-biofouling materials

A new method for the modification of poly(dimethylsiloxane) (PDMS) elastomer surfaces with hydrophilic poly(N-vinylpyrrolidone) (PVP) has been developed. PVP chains were grafted from the PDMS surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM) and water contact angle measurements. It was shown that the modified surfaces were strongly hydrophilic, indicating that the PVP grafts dominate the surface and define its properties. The anti-fouling properties of the grafted surfaces were demonstrated in protein adsorption and cell adhesion experiments. Both protein adsorption and cell adhesion were inhibited significantly on the PVP-modified PDMS surfaces compared to unmodified controls. It is concluded that modification by SI-ATRP grafting of PVP is an effective method for the preparation of anti-biofouling PDMS materials.

Site-Specific MicroRNA-92a Regulation of Krüppel-Like Factors 4 and 2 in Atherosusceptible Endothelium

Endothelial transcription factors Krüppel-like factor 4 (KLF4) and KLF2 are implicated in protection against atherogenesis. Steady-state microRNA (miR) regulation of KLFs in vivo is accessible by screening region-specific endothelial miRs and their targets. A subset of differentially expressed endothelial miRs was identified in atherosusceptible versus protected regions of normal swine aorta. In silico analyses predicted highly conserved binding sites in the 3'-untranslated region (3'UTR) of KLF4 for 5 miRs of the subset (miR-26a, -26b, -29a, -92a, and -103) and a single binding site for a miR-92a complex in the 3'UTR of KLF2. Of these, only miR-92a knockdown and knock-in resulted in responses of KLF4 and KLF2 expression in human arterial endothelial cells. Dual luciferase reporter assays demonstrated functional interactions of miR-92a with full-length 3'UTR sequences of both KLFs and with the specific binding elements therein. Two evolutionarily conserved miR-92a sites in KLF4 3'UTR and 1 site in KLF2 3'UTR were functionally validated. Knockdown of miR-92a in vitro resulted in partial rescue from cytokine-induced proinflammatory marker expression (monocyte chemotactic protein 1, vascular cell adhesion molecule-1, E-selectin, and endothelial nitric oxide synthase) that was attributable to enhanced KLF4 expression. Leukocyte-human arterial endothelial cell adhesion experiments supported this conclusion. In swine aortic arch endothelium, a site of atherosusceptibility where miR-92a expression was elevated, both KLFs were expressed at low levels relative to protected thoracic aorta. miR-92a coregulates KLF4 and KLF2 expression in arterial endothelium and contributes to phenotype heterogeneity associated with regional atherosusceptibility and protection in vivo.

The CD49d/CD29 complex is physically and functionally associated with CD38 in B-cell chronic lymphocytic leukemia cells

CD49d and CD38 are independent negative prognostic markers in chronic lymphocytic leukemia (CLL). Their associated expression marks a disease subset with a highly aggressive clinical course. Here, we demonstrate a constitutive physical association between the CD49d/CD29 integrin complex and CD38 in primary CLL cells and B-cell lines by (i) cocapping, (ii) coimmunoprecipitation and (iii) cell adhesion experiments using CD49d-specific substrates (vascular-cell adhesion molecule-1 or CS-1/H89 fibronectin fragments). The role of CD38 in CD49d-mediated cell adhesion was studied in CD49d(+)CD38(+) and CD49d(+)CD38(-) primary CLL cells, and confirmed using CD38 transfectants of the originally CD49d(+)CD38(-) CLL-derived cell line Mec-1. Results indicate that CD49d(+)CD38(+) cells adhered more efficiently onto CD49d-specific substrates than CD49d(+)CD38(-) cells (P < 0.001). Upon adhesion, CD49d(+)CD38(+) cells underwent distinctive changes in cell shape and morphology, with higher levels of phosphorylated Vav-1 than CD49d(+)CD38(-) cells (P = 0.0006) and a more complex distribution of F-actin to the adhesion sites. Lastly, adherent CD49d(+)CD38(+) cells were more resistant to serum-deprivation-induced (P < 0.001) and spontaneous (P = 0.03) apoptosis than the CD49d(+)CD38(-) counterpart. Altogether, our results point to a direct role for CD38 in enhancing CD49d-mediated adhesion processes in CLL, thus providing an explanation for the negative clinical impact exerted by these molecules when coexpressed in neoplastic cells.

Two-dimensional cantilever array with varying spring constants and tip radii for life-science applications

A fabrication process for realising two-dimensional cantilever arrays for parallel force spectroscopy of biological samples is presented. The parallel optical atomic force microscopy readout system has been developed and presented elsewhere. The arrays are designed either for (i) force-indentation onto living cells to obtain stiffness mapping or (ii) cell adhesion experiments. Both experiments require very different spring constants and tip radii of curvature. The arrays are based on silicon nitride cantilevers with molded tips. The fabrication process includes an advanced molding process and a thermocompression bonding of two silicon wafers. V-groove structures along the cantilevers, which increase the area moment of inertia, were introduced in the cantilever design. This feature enables the fabrication of cantilevers with different spring constants but same footprint from one wafer. An analytical model and experimental results confirmed that the spring constant of the cantilever (200 x 50 x 0.45 mu m) could be increased up to two decades (0.03-5 N/m) by changing the depth of the V-grooves. To realise the large tip radius required for cell adhesion experiments, an enlarging/rounding procedure has been applied to a truncated pyramidal tip mold. With this process, the authors obtained tips with a radius up to 4 mu m.

Engineered Nanostructured Coatings for Enhanced Protein Adsorption and Cell Growth

ABSTRACTWe designed and produced pure cubic zirconia (ZrO2) ceramic1 coatings by an ion beam assisted deposition (IBAD) with nanostructures comparable to the size of proteins. Our ceramic coatings exhibit high hardness and a zero contact angle with serum. In contrast to hydroxyapatite (HA), nano-engineered zirconia films possess excellent adhesion to all orthopaedic materials. Cell adhesion and proliferation experiments were performed with a bona fide mesenchymal stromal cell line (OMA-AD). Our experimental results indicate that the nano-engineered cubic zirconia is superior in supporting growth, adhesion, and proliferation. Since cell attachment is mediated by adhesive proteins such as fibronectin (FN), to elucidate why cells attach more effectively to our nanostructures, we performed a comparative analysis of adsorption energies of FN fragment using quantum mechanical calculations and Monte Carlo (MC) simulation both on smooth and nanostructured surfaces. We have found that a FN fragment adsorbs significantly stronger on the nanostructured surface than on the smooth surface2.

Grafting Carbon Nanotubes on Titanium Surface for Osteoblast Cell Adhesion and Growth

Poly(ethylene glycol) (PEG) functionalized single-walled carbon nanotubes (SWCNTs) were covalently grafted on the titanium surface with the aim to provide a new platform for human osteoblast cells (HOCs) attachment. Water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) results revealed that the PEG-functionalized SWCNTs were successfully grafted onto titanium surfaces. Cell viability and proliferation showed that the number of viable cells in culture medium increased with the incubation time for both titanium and SWCNT-modified titanium samples, although the SWCNT-modified titanium presented lower cell viability compared to titanium. Cell adhesion experiments suggested that there were no obvious differences in the number of cells adhered on the titanium and PEG-SWCNT-modified titanium, and the number of adhered cells increased with the culture time. To our best knowledge, for the first time the PEG functionalized SWCNTs were grafted on the titanium surface for human osteoblast cell adhesion and growth. The strategy introduced in the present study provides a new idea for the matrix preparation based on CNTs and titanium for the biological application and the new SWCNT-titanium platform has potential applications in implantable materials and bone tissue engineering.

Protein-resistant polymer surfaces

In this study, the results of protein adsorption on a wide spectrum of different surface-attached polymer networks are presented. The networks were generated from copolymers containing photoactive benzophenone groups or thermally activated azosulfonyl groups. The copolymers were deposited as thin films onto solid substrates and then (photo-)activated, which leads to crosslinking and the formation of surface-attached polymer networks. This simple preparation protocol allows the study of a wide range of polymer networks with well-defined hydrophilicity and/or charge and permits thus control of the degree of swelling in a contacting aqueous buffer solution. The so obtained polymer surfaces were exposed to solutions containing fibrinogen or other proteins and the amount of protein adsorbed was measured by surface plasmon resonance spectroscopy (SPR). It was found that strongly swollen polymer systems, which have only weak enthalpic interactions with the proteins, show strong protein repellency irrespective of the details of the chemical composition. We propose that conformational changes in the surface-attached polymer networks ('entropic shielding') and/or size exclusion effects dominate the adsorption behavior. In addition, we show first results of cell adhesion experiments of endothelial cells on these networks. It was found that surfaces which are protein resistant show also strong cell repellency, so that the surface-attached polymer networks might be used as a valuable tool to control cell adhesion.