Cell Adhesion Efficiency Research Articles

Identification of cell adhesion molecules for the maturation of engineered heart tissue

Abstract Background Engineered cardiac tissue (ECT) utilizing human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) is anticipated to function as a translational in vitro model. However, hiPSC-CMs display phenotypes indicative of immaturity, and the structural organization of ECT composed of hiPSC-CMs is insuficient when compared to that of mature adult hearts. Although the mechanisms for hiPSC-CMs maturation have been reported, little is known about the mechanisms regulating the formation of in vitro tissue such as ECT. Cell adhesion molecules play important roles in heart formation in vivo through cell-cell interactions. However, specific cell adhesion molecules responsible for tissue structure formation in in vitro tissue models, such as ECTs, have not been identified. We hypothesize that cell adhesion molecules, which regulate cell-cell attachment, are crucial for in vitro tissue formation. Purpose This study aims to identify the key cell adhesion molecules involved in cell-cell interaction and assess the effects of their expression on hiPSC-CMs and EHT functions. Methods and Results We developed a cell attachment assay to evaluate the attachment ability of hiPCS-CMs and discovered that hiPSC-CMs produced via embryoid body method (EB-hiPSC-CMs) exhibited a higher attachment ability than those produced by monolayer method (Mono-hiPSC-CMs). Further analysis revealed no significant difference in anoikis sensitivity between EB-hiPSC-CMs and Mono-hiPSC-CMs, suggesting that the observed difference in attachment ability were due to differencies in cell adhesion efficiency between hiPSC-CMs generated by two methods. Moreover, RNA-seq analysis identified nine cell adhesion molecule genes that were highly expressed in EB-hiPSC-CMs. We identified the cell adhesion molecules responsible for the attachment ability of hiPSC-CMs by knockdown and over-expression experiments. Moreover, over-expression experiments using adeno-associated virus (AAV) demonstrate that hiPSC-CMs with overexpression of a cell adhesion molecule improved calcium handling and increased propagation speed, and ECTs with overexpression of a cell adhesion molecule showed enhanced sarcomere alignment and sarcomere length compared to controls. Conclusion(s) We observed differences in attachment ability between hiPSC-CMs generated by two differentiation methods. Transcriptome analysis of these hiPSC-CMs identified key cell adhesion molecules that regulate cell-cell attachment ability of hiPSC-CMs. Furthermore, increment of attachment ability of hiPSC-CMs by overexpression of a cell adhesion molecule enhanced hiPSC-CMs and ECT functions.

Stable cytoactivity of piscine satellite cells in rice bran-gelatin hydrogel scaffold of cultured meat

In order to achieve high cell adhesion and growth efficiency on scaffolds for cultured meat, animal materials, especially gelatin, are necessary though the disadvantages of weak mechanical properties and poor stability of their hydrogel scaffolds are present during cell cultivation. Here, we use rice bran as a kind of filling and supporting materials to develop a composite scaffold with gelatin for fish cell cultivation, where rice bran is also inexpensive from high yield fibrous agricultural by-product. The rice bran (with a proportion of 1, 3, 5, 7, 10 to 3 of gelatin) could evenly distributed in the three-dimensional network composed of gelatin hydrogel. It contributed to delaying swelling and degradation rates, fixing water and improving elastic modulus. It is important that rice bran-gelatin hydrogel scaffolds (especially the hydrogel with 70 % rice bran, db) promoted piscine satellite cells (PSCs) proliferation effectively compared to the pure gelatin hydrogel, and the former could also support the differentiation of PSCs. Overall, this work showed a positive promotion to explore new source of scaffold materials like agricultural by-product for reducing the cost of cell cultured meat production.

Role of intercellular adhesion molecule-1 in adhesion and migration of mesenchymal stem cells in ankylosing spondylitis and its mechanisms

Objective: To investigate the role and underlying mechanisms of intercellular adhesion molecule-1 (ICAM-1) in the adhesion and migration of mesenchymal stem cells (MSCs) in patients with ankylosing spondylitis (AS). Methods: Bone marrow and ligament tissues were collected during surgery from patients with AS and thoracolumbar fractures (as controls, HC) treated from October 2021 to October 2022 at Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital. MSCs were isolated and cultured from the bone marrow using the Ficoll separation method. Cell morphology was observed under high-resolution microscopy, and differences in the cytoskeletal features between AS-and HC-MSCs were analyzed through immunofluorescence staining. The expression of ICAM-1 was quantified in both groups using real-time quantitative polymerase chain reaction (RT-qPCR) and flow cytometry. Transwell migration assays and wound healing experiments were conducted to evaluate the differences in migration rates between the two groups of MSCs. Results: The interspinous ligament and bone marrow was acquired in AS (2 males and 1 female; 33, 37, 32 years old, respectively) and no-AS patients (2 males and 1 female; 35, 32, 38 years old, respectively). AS-MSCs exhibited broader cell morphology compared to HC-MSCs under bright field and fluorescence microscopy. Immunofluorescence staining of the interspinous ligament showed higher expression of ICAM-1 (68.38±3.42 vs 48.31±2.43) and CD105 (37.97±2.16 vs 23.36±2.06) in AS patients (both P<0.001). Western blot and RT-qPCR analysis revealed significantly stronger protein expression and transcription levels of ICAM-1 in AS-MSCs when compared to those in HC-MSCs (both P<0.001). Flow cytometry confirmed greater mean fluorescence intensity of ICAM-1 in AS-MSCs than in that in HC-MSCs (924.30±54.99 vs 636.47±40.03, P=0.002). Regarding cell adhesion efficiency, it showed no significant difference between AS-MSCs and HC-MSCs in the early stage of adhesion (0.5 h: 1 496±213 vs 1 205±163, P=0.133), but they were all significantly higher in AS-MSCs in the later stage (1 h: 2 894±172 vs 1 908±155, P=0.002; 2 h: 4 540±286 vs 3 334±188, P=0.004; 3 h: 5 212±281 vs 4 208±303, P=0.014). Finally, cell migration experiments demonstrated a stronger migration capability of AS-MSCs compared to HC-MSCs (5 449±172 vs 4 016±155, P<0.001), and the inhibition efficiency of A-205804 on the migration rate of AS-MSCs was stronger than that on HC-MSCs (2 145±239 vs 3 539±316, P=0.004). Conclusions: The aberrant expression of ICAM-1 markedly influences the adhesion and migration dynamics of MSCs. Elevated ICAM-1 levels in MSCs derives from patients with AS significantly enhance their migratory capabilities.

Development of Super-Paramagnetic Iron Oxide Nanoparticle-Coated Melt Electrowritten Scaffolds for Biomedical Applications.

Polycaprolactone (PCL) is usually the material chosen for melt electrowriting (MEW) due to its biocompatibility, mechanical strength, and melt processability. This work first investigates the effect of different processing parameters to obtain optimum PCL-MEW scaffolds. Secondly, to increase PCL`s hydrophilicity and cell affinity, and to enable coating with superparamagnetic iron oxide nanoparticles (SPIONs) and silica-coated-SPIONs (Si-SPIONs), the scaffolds are modified with alkaline surface treatment. Finally, SPIONs and Si-SPIONs are successfully coated on MEW scaffolds. Results show that reproducible scaffolds are fabricated. Additionally, the alkaline treatment does not change the three-dimensionalmorphology of scaffolds while reducing fiber diameter. Furthermore, SEM images and ATR-FTIR results confirmed that SPIONs and Si-SPIONs-were coated on scaffolds. A cytocompatibility assay showed a non-toxic effect on MG-63 osteoblast-like cells in all scaffolds. Additionally, higher MC3T3-E1 pre-osteoblastic cell adhesion efficiency and proliferation are achieved for the alkaline-treated scaffolds and SPIONs/Si-SPIONs-coated scaffolds. All samples demonstrated the ability to generate heat, useful for hyperthermia-treatment, when subjected to an alternating magnetic field. Overall, the findings suggest that the strategy of coating PCL-MEW scaffolds with SPIONs/Si-SPIONs has the potential to improve scaffold performance for biomedical applications, especially for producing magnetically responsive MEW scaffolds.

Water-soluble PEG segmented mannose-based macromolecules: Synthesis, characterization and their biocompatibility

The macromolecular architectures, namely mannose-based methacrylate acetyl-mannopyranoside and PEG block copolymers [AB type copolymer [PEG-b-PMAM], poly(ethyleneglycol)-b-poly(methacryl-2,3,4,6-tetra-O-acetyl-D-mannopyranoside) and ABA type copolymer [PMAM-b-PEG-b-PMAM], poly(methacryl-2,3,4,6-tetra-O-acetyl-D-mannopyranoside)-b-poly(ethyleneglycol)-b-poly(methacryl-2,3,4,6-tetra-O-acetyl-D-mannopyranoside)] were synthesized by atom transfer radical polymerization (ATRP) method that were deacetylated to generate the corresponding water-soluble and biocompatible glycopolymer macromolecules. The molecular weight of acetyl and deacetylate macromolecules was in the range of 7083–9499 and 4659–6026, as determined by GPC and proton NMR spectra. The 5 % decomposition temperatures for acetylated methacrylate macromolecules (218–299 °C) were higher than the corresponding water-soluble macromolecules (204–248 °C). The conjugation of poly(methacryl-2,3,4,6-tetra-O-acetyl-D-mannopyranoside) (PMAM) segment with the PEG block decreased the glass transition (Tg) value, and the water-soluble macromolecules displayed Tg in the range of 92–95 °C. The biocompatibility of the synthesized water-soluble mannose-based macromolecules was determined using Human Bone Derived Cells (HBDC) culture with the TCP (Tissue culture plastic) template as control. Using three different concentrations of the synthesized glycopolymers, HBDC's were cultured for 1, 3, and 7 days. The effect of mannomethacrylate macromolecules on mitochondrial activity of HBDC's was estimated using colorimetry that showed the conversion of MTS [3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium-bromide] to formazan (MTS assay). ABA type diblock copolymer architecture exhibited increased absorbance values of 3 and 7 day cultures at 1–100 M concentrations, with the highest values observed at a concentration of 1 M for day 3 cultures. The design of these novel mannose-based macromolecules is important for improving cell proliferation, cell adhesion, and osteointegration efficiency.

Self Assemblies of Poly(ether ether ketone) Block Copolymers for Biomedical Applications

AbstractOriented and ordered domains in an unusual engineering homopolymer known as poly ether ether ketone (PEEK) are stimulated by attaching a phosphonated ionic segment to its both ends. Such orientation of polymer chains leads to the formation of nanoparticles in solution. The ordered domains contain the stacks of rigid polymer chains that result into the crystalline regions appearing in rather unusual manner. Here, the molecular motions and reorganization are reinforced by hydrogen bonds, and not by annealing. On a silicone surface i. e. a substitute for titanium in implants, these copolymer attach via ionic groups and consequently the molecular self assemblies get disrupted. The corresponding copolymer films show submicrometer sized roughness, and hence can improve adhesion significantly. The self assemblies induced and generated simultaneously contain functional groups and can bind to a metallic surface for biomedical applications e. g. bone implants. These block copolymers as bone or dental implants can be superior to the ones based on modified PEEKs where the degree of modification can be problematic and can compromise the properties of PEEK. In addition, tri‐block copolymers described here can be better alternatives for bone implants due to their cell adhesion efficiency via ionic groups and thermal stability including reasonable biocompatibility.

Characterization and Cytotoxicity Comparison of Silver- and Silica-Based Nanostructures.

Core-shell structures are the most common type of composite material nanostructures due to their multifunctional properties. Silver nanoparticles show broad antimicrobial activity, but the safety of their utilization still remains an issue to tackle. In many applications, the silver core is coated with inorganic shell to reduce the metal toxicity. This article presents the synthesis of various materials based on silver and silica nanoparticles, including SiO2@Ag, Ag@SiO2, and sandwich nanostructures—Ag@SiO2@Ag—and the morphology of these nanomaterials based on transmission electron microscopy (TEM), UV-Vis spectroscopy, and FT-IR spectroscopy. Moreover, we conducted the angle measurements due to the strong relationship between the level of surface wettability and cell adhesion efficiency. The main aim of the study was to determine the cytotoxicity of the obtained materials against two types of human skin cells—keratinocytes (HaCaT) and fibroblasts (HDF). We found that among all the obtained structures, SiO2@Ag and Ag@SiO2 showed the lowest cell toxicity and very high half-maximal inhibitory concentration. Moreover, the measurements of the contact angle showed that Ag@SiO2 nanostructures were different from other materials due to their superhydrophilic nature. The novel approach presented here shows the promise of implementing core-shell type nanomaterials in skin-applied cosmetic or medical products.

Fabrication and in vitro evaluation of PCL/gelatin hierarchical scaffolds based on melt electrospinning writing and solution electrospinning for bone regeneration

As an emerging 3D printing technique, melt electrospinning writing (MEW) has been used to fabricate scaffolds with controllable structure and good mechanical strength for bone regeneration. However, how to further improve MEW scaffolds with nanoscale extracellular matrix (ECM) mimic structure and bioactivity is still challenging. In this study, we proposed a simple composite process by combining MEW and solution electrospinning (SE) to fabricate a micro/nano hierarchical scaffold for bone tissue engineering. The morphological results confirmed the hierarchical structure with both well-defined MEW microfibrous grid structure and SE random nanofiber morphology. The addition of gelatin nanofibers turned the scaffolds to be hydrophilic, and led to a slight enhancement of mechanical strength. Compared with PCL MEW scaffolds, higher cell adhesion efficiency, improved cell proliferation and higher osteoinductive ability were achieved for the MEW/SE composite scaffolds. Finally, multilayer composite scaffolds were fabricated by alternately stacking of MEW layer and SE layer and used to assess the effect on cell ingrowth in the scaffolds. The results showed that gelatin nanofibers did not inhibit cell penetration, but promoted the three-dimensional growth of bone cells. Thus, the strategy of the combined use of MEW and SE is a potential method to fabricate micro/nano hierarchical scaffolds to improve bone regeneration.

Adhesion and proliferation of living cell on surface functionalized with glycine nanostructures

AbstractThis research presents the application of glycine amino acid for establishing firm cell‐substrate interaction instead of expensive adhesion proteins, peptides and peptide derivatives. The glycine amino acid is chemically functionalized on the coverslip to achieve self‐assembled nanostructure. Glycine self‐assembly on NaCl treated coverslips is initiated with SiONa+:COO−linkage while their nanostructure is achieved with formation of glycine chain through NH3+:COO−covalent linkage between the adjacent molecules. The functionalization steps are confirmed by Fourier‐transform infrared spectroscopy (FTIR) investigation. The atomic force microscopy (AFM) and scanning electron microscopy (SEM) investigations reveal that glycine growth initiates at 4 Hours (H) post‐treatment while maximum growth appears after 8H‐10H. Both the vertical and horizontal growth of nanostructures show dependence on functionalization periods. Various levels of glycine functionalized surface show different levels of baby hamster kidney (BHK‐21) cell adhesion and proliferation efficiency with maximum performance for 10H functionalized surface. The adhesion and proliferation performance of 10H glycine functionalized surface shows negligible difference when compared with glycine‐aspartic acid (RGD) functionalized surface. Finally, growth curves obtained from both glycine and RGD functionalized surface reveal exponential growth phage up to 48H followed by stationary phage between 48H and 72H while death of many cells appears from 72H to 96H. Thus, this research concluded that glycine functionalized surface is equally effective for cell adhesion and proliferation.

Extending the Half-Life of a Protein in Vivo by Enzymatic Labeling with Amphiphilic Lipopeptides.

Synthesis of lipid-protein conjugates is one of the significant techniques in drug delivery systems of proteins; however, the intact conjugation of a lipid and protein is yet challenging due to the hydrophobicity of lipid molecules. In order to facilitate easy handling of the lipid moiety in conjugation, we have focused on a microbial transglutaminase (MTG) that can ligate specific lysine (K) and glutamine (Q) residues in lipopeptides and a protein of interest. As MTG substrates, monolipid- and dilipid-fused amphiphilic short lipopeptide substrates (lipid-G3S-RHK or lipid2-KG3S-RHK) were designed. These amphiphilic lipopeptides and a model protein (enhanced green fluorescent protein, EGFP) fused with LLQG (LQ-EGFP) were both water-soluble, and thus lipid-protein conjugates were efficiently obtained through the MTG reaction with a >80% conversion rate of LQ-EGFP even using cholesterol-G3S-RHK. In vitro cell adhesion and in vivo half-life stability of the successfully obtained lipid-protein conjugates were evaluated, showing that the monocholesterol-G3S-RHK modification of a protein gave the highest cell adhesion efficiency and longest half-life time by formation of a stable albumin/lipid-protein complex.

Structure-function assessment of 3D-printed porous scaffolds by a low-cost/open source fused filament fabrication printer

Additive manufacturing encompasses a plethora of techniques to manufacture structures from a computational model. Among them, fused filament fabrication (FFF) relies on heating thermoplastics to their fusion point and extruding the material through a nozzle in a controlled pattern. FFF is a suitable technique for tissue engineering, given that allows the fabrication of 3D-scaffolds, which are utilized for tissue regeneration purposes. The objective of this study is to assess a low-cost/open-source 3D printer (In-House), by manufacturing both solid and porous samples with relevant microarchitecture in the physiological range (100–500 μm pore size), using an equivalent commercial counterpart for comparison. For this, compressive tests in solid and porous scaffolds manufactured in both printers were performed, comparing the results with finite element analysis (FEA) models. Additionally, a microarchitectural analysis was done in samples from both printers, comparing the measurements of both pore size and porosity to their corresponding computer-aided design (CAD) models. Moreover, a preliminary biological assessment was performed using scaffolds from our In-House printer, measuring cell adhesion efficiency. Finally, Fourier transform infrared spectroscopy – attenuated total reflectance (FTIR–ATR) was performed to evaluate chemical changes in the material (polylactic acid) after fabrication in each printer. The results show that the In-House printer achieved generally better mechanical behavior and resolution capacity than its commercial counterpart, by comparing with their FEA and CAD models, respectively. Moreover, a preliminary biological assessment indicates the feasibility of the In-House printer to be used in tissue engineering applications. The results also show the influence of pore geometry on mechanical properties of 3D-scaffolds and demonstrate that properties such as the apparent elastic modulus (Eapp) can be controlled in 3D-printed scaffolds.

Abstract PO-042: Nanoparticles imaging for cancer metastasis diagnosis

Abstract The main cause of cancer-related mortality is metastasis; thus, its prediction can critically affect the survival rate. Metastases are currently predicted by lymph-node status, tumor size, histopathology and genetic testing, however, all these are not infallible and getting the results may require weeks. The identification new potential prognostic factors will be an important source of risk information for the practicing oncologist, potentially leading to enhanced patient care through the proactive optimization of treatment strategies. We propose to use fluorescent nanoparticles for metastasis detection. Nowadays nanoparticles are widely used for targeted drug delivery, while particles with specific coatings are encapsulated by cancer cells via endocytosis. We have used low-cost carboxylate-modified fluorescent 200 nm particles to achieve the adhesion and encapsulation efficiency of breast cancer cells with high (MDA-MB-231) and low (MCF7) metastatic potential. Using high-content fluorescence imaging microscope (ImageXpress Micro XL), we have discovered that during short time (up to 1h) highly metastatic cells are able to adhere and encapsulate sufficiently more (p&amp;lt;0.05) nanoparticles than lowly metastatic cells. We have created automatic image analysis algorithms to find quantitative colocalization (Pearson’s and Overlap coefficients) of fluorescent nanoparticles with imaged cells. Migration and invasion of cancer cells is a critical step in metastases formation. The cytoskeleton machinery mechanisms (i.e. actin network), utilized by metastatic cells for invasion process have been found similar to the involvement of actin cytoskeleton in endocytosis process. From the other side, for migration process cells use adhesive structures (developed also by nano-particles adhesion) to probe their surroundings and adapt their mechanical properties. We have previously characterized the invasive and migrative abilities of breast cancer cells, as well as patient-derived tumor cells, by indentation and migration assays. We have achieved quantitative and significantly different results for various cancer cells; however, the data-acquisition of such kind assays requires 4-72hs. The obtained results of encapsulation and adhesion efficiency may lead to developing novel clinical tool for metastasis prediction. The proposed here method is very simple, it does not require neither expensive materials and equipment nor cell manipulations (e.g. serum starvation, staining, expansion), it is potentially suitable for a variety of cells. Rapid (up to 1h), quantitative, patient-specific determination of the metastatic likelihood from biopsy/surgery sample, will directly affect the choice of treatment protocols for cancer patients and eventually increase their life-expectancy. Citation Format: Yulia Merkher, Elizaveta Kontareva, Anna Melekhova, Sergey Leonov. Nanoparticles imaging for cancer metastasis diagnosis [abstract]. In: Proceedings of the AACR Virtual Special Conference on Artificial Intelligence, Diagnosis, and Imaging; 2021 Jan 13-14. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(5_Suppl):Abstract nr PO-042.

Effect of the mechanical properties of carbon-based coatings on the mechanics of cell–material interactions

The paper presents an influence of the surface mechanical properties of thin-film materials on blood cell adhesion under shear stress conditions. Physical vapour deposited (PVD) coatings i.e. hydrogenated amorphous carbon (a-C:H) doped with nitrogen or silicon have been investigated. The mechanical properties of materials, namely their microhardness and Young’s modulus were measured using indentation test with Rockwell indenter. The adhesion efficiency of blood cells in dynamic conditions were analysed using a radial flow chamber. Red blood cells (RBC) were used as representative cells to analyse cell–material interactions. The biomaterial examinations were performed under physiological flow conditions at the single-cell level. The 3D FVM (finite volume method) model of multi-phase radial flow test was developed to reproduce the physical test and to predict distributions of shear stresses and velocity during blood washout with PBS. Cell–material interactions were found to be strongly associated with the mechanical properties of the thin-film material. The decrease in the hardness of the coatings translated into a weaker cell – material interactions.

Dual-functional anti-adhesion barrier prepared using micro-hierarchical structured and neutralized shellac films for drug release

Micro-hierarchical structured shellac films were prepared using a solution casting method with dodecyltrichloro-immobilized shellac microparticles. We evaluated two opposite surfaces of the shellac films—one a micro-hierarchical structured side and the other a neutralized shellac side using alkali ethanol—for their applications in the medical field. A bending strength test using a tensile strength testing machine and measurement of surface hardness using a scratch hardness tester indicated that the optimal composition of the base films comprised 15% shellac and 10% calcium phosphate as durability promoting agents. Further, dodecyltrichloro-immobilized shellac microparticles were synthesized and spray-deposited on the films. The solubility of shellac increased as the pH of the shellac solution increased. Analyses of cell adhesion, proliferation, and anti-thrombus efficiency were performed using a WST assay, field emission scanning electron microscope, and hemocytometer. The contact angle with the micro-hierarchical structure surface was approximately 150°. The spray-deposited shellac film yielded a lower cell and platelet adhesion rate (20%) than the untreated film. These results indicate that the micro-hierarchical structure has unique properties and that this novel superhydrophobic biodegradable shellac film can be applied as a blood/tissue-compatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier.

Protocol of mesenchymal stem cell inoculation to nonwoven fabric scaffold.

To obtain a large number of human mesenchymal stem cell (hMSCs) for allograft, nonwoven fabrics (NWF) were used as a cell culture scaffold. NWF are three-dimensional fiber aggregates formed by heat bonding and have a high surface area for cell adhesion and elongation. Inoculation hMSC was done to a center of NWF disc (diameter, 15.1mm; depth, 0.1mm). A cell suspension inoculum had a volume of 10µL, which was close to the void volume of the disc, and resulted in a high initial (24h) cell adhesion efficiency. Use of green fluorescent protein expressing rat MSCs and fluorescence microscopy revealed that adding an additional 10μL of medium at 0-2h after the cell inoculation made the initial horizontal distribution of cells in the NWF disc more uniform. Addition of 10μL of the medium after 1 and 2h of hMSC inoculation (0.15 × 103 cells/cm2 NWF-fiber) markedly increased the final cell density (21days) from 2.48 to 7.45 × 103 cells/cm2 NWF-fiber and fold increase in cell density by 16-48-fold. In conclusion, the addition of an additional medium after inoculation made the initial cells distribution in NWF more uniform, which might result in higher final cell density.

Topographical Features of Graphene-Oxide-Functionalized Substrates Modulate Cancer and Healthy Cell Adhesion Based on the Cell Tissue of Origin

Graphene-derived materials, such as graphene oxide (GO), have been widely explored for biomedical and biological applications, including cancer research. Despite some recent works proving that GO inhibits the migration and invasion of different cancer cells, so far most of these in vitro studies have been conducted using GO sheets dispersed in solution or as a planar film. On the contrary, little is known about cellular activities, such as cell viability, adhesion, and spreading, when cancer cells interface with GO functionalized hydrogel-based surfaces, biomechanically and structurally more similar to the tumor environment. Here, we evaluate the interactions of human breast cancer cells (MDA-MB-231) with alginate (Alg)/GO hydrogel-based substrates, and compare them with a cancer cell line from human osteosarcoma (HOS) and healthy murine fibroblasts (3T3). We observed that GO addition selectively inhibits malignant breast cancer cell adhesion efficiency and spreading area, while promotes HOS and 3T3 adhesive processes. Furthermore, we did not observe the same results over Alg substrates with GO nanosheets dispersed in the medium, without embedment into the Alg. This suggests that cancer (MDA-MB-231 and HOS) and healthy (3T3) cell adhesion efficacy does not depend on the cellular tumoral nature and it is driven by the topographical cues provided by the GO-based substrates, whose physical-mechanical characteristics better mimic those of the cell native tissue. We envision that this study can provide a rational for future design and use of graphene-based nanomaterials for cancer research by deepening the knowledge of graphene-cancer cell specific interactions.

Polydimethylsiloxane Films Modified with Chitosan/Pectin Multilayers as Scaffolds for Mesenchymal Stem Cells

Solid (smooth) and porous films of polydimethylsiloxane (PDMS) have been obtained; the effect of their structure on the adhesion of mesenchymal stem cells (MSCs) on their surface was found. It is shown that modification of these films with a (chitosan/pectin)4 multilayer increased the efficiency of viable cell adhesion. A (3-aminopropyl)triethoxysilane–glutaraldehyde system was used to enhance the binding of the polysaccharide layer to the hydrophobic surface of PDMS. It was found that MSCs formed a monolayer culture of the fibroblast-like cells with high viability on porous PDMS modified with (chitosan/pectin)4.

A physico-chemical approach to the study of genipin crosslinking of biofabricated peptide hydrogels

Peptide-based hydrogels have been widely used for both tissue engineering approaches and therapeutic drug delivery mainly thanks to their tissue-like water content and tunable physicochemical properties. In particular, the modulation of the hydrogel chemical structure influences hydrogel properties. The most common approach for tuning hydrogel properties in terms of cell adhesion or release efficiency of entrapped compounds is chemical crosslinking. In this study Fluorenylmethyloxycarbonyl (Fmoc)-tripeptide hydrogels were synthetized in the presence of Genipin as a crosslinker using a biocatalyzed reverse hydrolysis reaction occurring between FmocPhe and Phe2 in the presence of Pseudomonas fluorescens lipase. Infrared Attenuated Total Reflection (IR-ATR), Liquid Chromatography coupled to Mass Spectrometry (LC-MS) and Scanning Electron Microscopy (SEM) investigations were used to investigate the interaction of Genipin with Fmoc-peptides as well as with their precursors. The whole instrumental platform allowed us to identify two crosslinked products that had never been reported previously and provide deeper insight into the use of natural crosslinkers for peptide hydrogel modification.

Cooptimization of Adhesion and Power Conversion Efficiency of Organic Solar Cells by Controlling Surface Energy of Buffer Layers

Here, we demonstrate the cooptimization of the interfacial fracture energy and power conversion efficiency (PCE) of poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT)-based organic solar cells (OSCs) by surface treatments of the buffer layer. The investigated surface treatments of the buffer layer simultaneously changed the crack path and interfacial fracture energy of OSCs under mechanical stress and the work function of the buffer layer. To investigate the effects of surface treatments, the work of adhesion values were calculated and matched with the experimental results based on the Owens-Wendt model. Subsequently, we fabricated OSCs on surface-treated buffer layers. In particular, ZnO layers treated with poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) simultaneously satisfied the high mechanical reliability and PCE of OSCs by achieving high work of adhesion and optimized work function.

Transforming growth factor β1 enhances adhesion of endometrial cells to mesothelium by regulating integrin expression.

Endometriosis is the abnormal growth of endometrial cells outside the uterus, causing pelvic pain and infertility. Furthermore, adhesion of endometrial tissue fragments to pelvic mesothelium is required for the initial step of endometriosis formation outside uterus. TGF-β1 and adhesion molecules importantly function for adhesion of endometrial tissue fragments to mesothelium outside uterus. However, the function of TGF-β1 on the regulation of adhesion molecule expression for adhesion of endometrial tissue fragments to mesothelium has not been fully elucidated. Interestingly, transforming growth factor β1 (TGF-β1) expression was higher in endome-triotic epithelial cells than in normal endometrial cells. The adhesion efficiency of endometriotic epithelial cells to meso-thelial cells was also higher than that of normal endometrial cells. Moreover, TGF-β1 directly induced the adhesion of endometrial cells to mesothelial cells through the regulation of integrin of αV, α6, β1, and β4 via the activation of the TGF-β1/TGF-βRI/Smad2 signaling pathway. Conversely, the adhesion of TGF-β1-stimulated endometrial cells to mesothelial cells was clearly reduced following treatment with neutralizing antibodies against specific TGF-β1-mediated integrins αV, β1, and β4 on the endometrial cell membrane. Taken together, these results suggest that TGF-β1 may act to promote the initiation of endometriosis by enhancing integrin-mediated cell-cell adhesion.