Cell Adhesion Behavior Research Articles

Effect of Grain Refinement by Laser Surface Treatment on Cell Adhesion Behavior of AZ91D Magnesium Alloy

Abstract Laser surface melting (LSM) has been widely reported for corrosion protection to magnesium alloys. However, magnesium alloys are much better known as implant materials; thus, in this work, cell adhesion behavior of AZ91D magnesium alloy by LSM treatment was investigated. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), contact angle measurements, hydrogen evolution tests, and cell culture study were used to characterize the microstructure, composition, surface energy, biodegradability, cell adhesion behavior, and cytocompatibility, respectively. Results showed that the biodegradation rate decreased, the surface energy (42.9 ± 1.3 mJ/m2, N = 10) was higher than that of the as-received one (23.1 ± 1.2 mJ/m2, N = 10), and the average surface roughness value (Ra) increased from 0.16 ± 0.02 μm to 2.53 ± 0.03 μm after LSM treatment. The laser-surface-treated magnesium alloys presented good cytocompatibility, and the cell adhesion on the surface of magnesium alloy was improved because of the higher surface energy, lower degradation, and increased roughness.

Viscoelastically tunable substrates elucidate the interface-relaxation-dependent adhesion and assembly behaviors of epithelial cells

Recent progress in mechanobiology sheds light on the regulation of cellular phenotypes by dissipative property of matrices, i.e., viscosity, fluidity, and stress relaxation, in addition to extensively studied elasticity. However, most researches have focused on bulk mechanics, despite cells in 2D culture can only interact with matrix interface directly. Here, we studied the impact of interfacial viscosity as well as elasticity of substrates on the early stage of adhesion behaviors of epithelial cells through new material design and mechanical characterization. The materials are copolymers of ε-caprolactone and d,l-lactide photocrosslinked by benzophenone. The substrate viscoelasticity changes depending on the polymer molecular weight and irradiation time. The interfacial elasticity and relaxation were determined by atomic force microscopy with modes of nanoindentation and tip-dwelling, respectively. MDCK cells changed morphologically, ranging from loose beaded assembly to more compact spheroids and eventual spread monolayer clusters, in response to the interfacial viscoelasticity change. Such morphological changes were mainly determined by substrate interfacial relaxation, rather than interfacial elasticity. Single-cell tracking identified biphasic motility with the minimum speed at intermediate relaxation time (~350 ms), where cells showed transitional morphologies between epithelial and mesenchymal traits. In that relaxation level, partially deformed cells moved around to coalesce with surrounding cells, eventually assembling into compact cellular aggregates. These results highlight, unlike the conventional hanging-drop technique, an appropriate level of interfacial relaxation is critical for efficient cell aggregate maturation on adhesive viscoelastic matrices. This work not only elucidates that the interfacial relaxation as the essential mechanical parameter for epithelial cell adhesion and migration, but also gives useful tips for creating physiologically relevant drug screening platform.

Surface Modifications of Titanium Aluminium Vanadium Improve Biocompatibility and Osteogenic Differentiation Potential.

Osteogenic cells are strongly influenced in their behaviour by the surface properties of orthopaedic implant materials. Mesenchymal stem and progenitor cells (MSPCs) migrate to the bone–implant interface, adhere to the material surface, proliferate and subsequently differentiate into osteoblasts, which are responsible for the formation of the bone matrix. Five surface topographies on titanium aluminium vanadium (TiAl6V4) were engineered to investigate biocompatibility and adhesion potential of human osteoblasts and the changes in osteogenic differentiation of MSPCs. Elemental analysis of TiAl6V4 discs coated with titanium nitride (TiN), silver (Ag), roughened surface, and pure titanium (cpTi) surface was analysed using energy-dispersive X-ray spectroscopy and scanning electron microscopy. In vitro cell viability, cytotoxicity, adhesion behaviour, and osteogenic differentiation potential were measured via CellTiter-Glo, CytoTox, ELISA, Luminex® technology, and RT-PCR respectively. The Ag coating reduced the growth of osteoblasts, whereas the viability of MSPCs increased significantly. The roughened and the cpTi surface improved the viability of all cell types. The additive coatings of the TiAl6V4 alloy improved the adhesion of osteoblasts and MSPCs. With regard to the osteogenic differentiation potential, an enhanced effect has been demonstrated, especially in the case of roughened and cpTi coatings.

Unidirectional Water-Transport Antibacterial Trilayered Nanofiber-Based Wound Dressings Induced by Hydrophilic-Hydrophobic Gradient and Self-Pumping Effects

Excessive wound exudates often cause infection and hinder wound repair and regeneration. It is therefore urgently needed to develop an ideal wound dressing for pumping the excessive biofluids and inhibiting bacterial infection in the wound healing process. Herein, we demonstrate a facile and efficient strategy to fabricate the unidirectional water-transport antibacterial wound dressings by embedding macromolecular antimicrobials into a multilayer nanofibrous membrane featured with hydrophobic-to-hydrophilic gradient structure and self-pumping effect using an electrospinning technique. Thanks to these features, the obtained nanofibrous dressings achieved excellent unidirectional water-transport performance, which could drive wound exudates to flow spontaneously from inside to outside and prevent pumped biofluids rewetting the wounds. In addition, the designed trilayered dressing exhibited approximately 100% antibacterial ability against Staphylococcus aureus and Escherichia coli when the concentration of antibacterial agents polyhexamethylene guanidine hydrochloride (PHGC) was 0.06 wt%. Moreover, the trilayered dressings revealed excellent water absorption performance, air and moisture permeability, mechanical strength, biocompatibility, and low cell adhesion behavior, indicating the potential applications for the trilayered nanofibrous wound dressings in wound care.

Ti-Cu-Zr-Fe-Sn-Si-Ag-Pd Bulk Metallic Glasses with Potential for Biomedical Applications

Ti47Cu38−xZr7.5Fe2.5Sn2Si1Ag2Pdx (x = 1, 2, 3, and 4 atomic percent, at. pct) bulk metallic glasses (BMGs) with potential for biomedical applications were fabricated by copper-mold casting. The Ti-based BMGs exhibited high glass-forming ability (GFA) with critical diameters of 4 to 5 mm and a supercooled liquid region over 50 K, though the high contents of Pd slightly decreased the GFA. The additions of 2 and 3 at. pct Pd benefited the improvement of plasticity, and the resultant BMGs showed the relatively low Young’s modulus of about 100 GPa, high compressive strengths of 2174 to 2340 MPa, and compressive plastic strain of around 4 pct. The addition of Pd also decreased the passive current density and increased the pitting potential of the Ti-based BMGs in the Hank’s solution, leading to the enhanced bio-corrosion resistance of the BMGs. Furthermore, the cell adhesion, viability, and proliferation behaviors revealed that the present Ti-based BMGs possess as good biocompatibility as that of the Ti-6Al-4V alloy. These results demonstrated the potential of the Ti-Cu-Zr-Fe-Sn-Si-Ag-Pd BMGs as biomedical materials.

Bone Formation: Rolled‐Up Metal Oxide Microscaffolds to Study Early Bone Formation at Single Cell Resolution (Small 12/2021)

Transparent Ti-45Nb 3D microstructures offer an elegant way to study single bone cell-implant material interactions and pore size effects in vitro. In article number 2005527, Mariana Medina-Sánchez and co-workers present this technology as an excellent tool to live monitor cell migration and adhesion behavior changes deriving from highly constricted microenvironments, while also providing deeper insights on cell death related bone mineralization processes in low nutrition conditions.

Structural Features of the Algal Cell Determine Adhesion Behavior at a Charged Interface

AbstractWe aimed to examine the effects of algal structural features on adhesion at a charged interface. Results showed that algae with a glycocalyx, and with a cellulose amphiesma adhered at a charged interface at species‐specific potential ranges. Algae, encased with a calcite‐encrusted theca, and with an organosilicate cell wall, did not adhere to the interface. These differences in the amperometrically determined adhesion behavior of algal cells are in agreement with reported cell mechanical properties. Critical interfacial tensions of adhesion show differences between the studied soft algal cells as a consequence of their distinct cell barrier structure, composition, and properties.

Unidirectional water-transport antibacterial trilayered nanofiber-based wound dressings induced by hydrophilic-hydrophobic gradient and self-pumping effects

Excessive wound exudates often cause infection and hinder wound repair and regeneration. It is therefore urgently needed to develop an ideal wound dressing for pumping the excessive biofluids and inhibiting bacterial infection in the wound healing process. Herein, we demonstrate a facile and efficient strategy to fabricate the unidirectional water-transport antibacterial wound dressings by embedding macromolecular antimicrobials into a multilayer nanofibrous membrane featured with hydrophobic-to-hydrophilic gradient structure and self-pumping effect using an electrospinning technique. Thanks to these features, the obtained nanofibrous dressings achieved excellent unidirectional water-transport performance, which could drive wound exudates to flow spontaneously from inside to outside and prevent pumped biofluids rewetting the wounds. In addition, the designed trilayered dressing exhibited approximately 100% antibacterial ability against Staphylococcus aureus and Escherichia coli when the concentration of antibacterial agents polyhexamethylene guanidine hydrochloride (PHGC) was 0.06 wt%. Moreover, the trilayered dressings revealed excellent water absorption performance, air and moisture permeability, mechanical strength, biocompatibility, and low cell adhesion behavior, indicating the potential applications for the trilayered nanofibrous wound dressings in wound care.

Finite Element Model for Cardiac Cell mechano-electrical stimulation

Cardiomyocyte behavior is highly dependent on the mechanical and electrical stimuli. We present a computational model, based on the FEM, to evaluate their behavior under electro-mechanical stimulation. Cell migration, adhesion, and collective behavior have been considered. Low stiffness and high alternating electric field have shown to be the best combination.

Fe-doped tricalcium phosphates: crystal structure and degradation behavior

β-tricalcium phosphate (β-TCP, Ca3(PO4)2) is biodegradable ceramics with chemical and mineral compositions similar to those of bone. It is a potential candidate for bone repair surgery, and substituting the Fe ions can improve its biological behavior. In this study, we investigated the effect of Fe ions on the structural deviation and in vitro behavior of β-TCP. Fe-doped β-TCP were synthesized by the co-precipitation method, and the heat treatment temperature was set at 1100 °C. The chemical state of the Fe-doped β-TCP was analyzed by x-ray photoelectron spectroscopy, while structural analysis was carried out by Rietveld refinement using the x-ray diffraction results. Fe ions existed in both Fe2+ and Fe3+ states and occupied the Ca-(4) and Ca-(5) sites. Fe ions enhanced the degradation of β-TCP and resorption behavior onto the surface of β-TCP during the immersion test. As a result, Fe ion improves the initial cell adhesion and proliferation behavior of β-TCP.

Cell Adhesion and Migration Behaviors on Patterned Thermoresponsive Microgel Stripes.

Cell adhesion and migration behaviors are influenced by their surrounding environments. In this work, patterned poly(N-isopropylacrylamide-styrene) (pNIPAAmSt) microgel stripes, which can provide a more complex environment, were fabricated on polyethyleneimine (PEI)-precoated glass substrate, and their effects on cell adhesion and migration behavior were investigated. The results showed that patterned cell layers can be formed on the space regions either by selective adhesion of the cells or by detaching the attached cells from the thermoresponsive microgel stripes via mild temperature stimuli. The migration behavior of the cells was affected by both the cell types and the width of the microgel stripes. The wider the microgel stripe, the harder it is for the cells to migrate, and the longer the patterned cell layers can be conserved. It is worth noting that the cell-cell interaction in the cocultured system plays a key role in the cell migration process. This work may offer a platform to study the adhesion and migration behavior of mono/cocultured cells in a more controllable system.

Microgravity-Induced Cell-to-Cell Junctional Contacts Are Counteracted by Antioxidant Compounds in TCam-2 Seminoma Cells

The direct impact of microgravity exposure on male germ cells, as well as on their malignant counterparts, has not been largely studied. In previous works, we reported our findings on a cell line derived from a human seminoma lesion (TCam-2 cell line) showing that acute exposure to simulated microgravity altered microtubule orientation, induced autophagy, and modified cell metabolism stimulating ROS production. Moreover, we demonstrated that the antioxidant administration prevented both TCam-2 microgravity-induced microtubule disorientation and autophagy induction. Herein, expanding previous investigations, we report that simulated microgravity exposure for 24 h induced the appearance, at an ultrastructural level, of cell-to-cell junctional contacts that were not detectable in cells grown at 1 g. In line with this result, pan-cadherin immunofluorescence analyzed by confocal microscopy, revealed the clustering of this marker at the plasma membrane level on microgravity exposed TCam-2 cells. The upregulation of cadherin was confirmed by Western blot analyses. Furthermore, we demonstrated that the microgravity-induced ROS increase was responsible for the distribution of cadherin nearby the plasma membrane, together with beta-catenin since the administration of antioxidants prevented this microgravity-dependent phenomenon. These results shed new light on the microgravity-induced modifications of the cell adhesive behavior and highlight the role of ROS as microgravity activated signal molecules.

Comparative toxicological effects of planktonic Microcystis and benthic Oscillatoria on zebrafish embryonic development: Implications for cyanobacteria risk assessment.

Planktonic and benthic cyanobacteria blooms are increasing in frequency in recent years. Although many studies have focused on the effects of purified toxins or cyanobacteria extracts on fish developments, the more complex impacts of cyanobacteria cells on fish populations are still considered insufficient. This study compared the toxicological effects of harmful planktonic Microcystis and benthic Oscillatoria on zebrafish (Danio rerio) early stages of development. Zebrafish embryos, at 1-2h post fertilization (hpf), were exposed to 5, 10, and 20×105cells/mL Microcystis (producing microcystins) or Oscillatoria (producing cylindrospermopsins) until 96 hpf. The results indicated that the effects of benthic Oscillatoria on embryonic development of zebrafish were different from those of planktonic Microcystis. Reduced hatching rates, increased mortality, depressed heart rates and elevated malformation rates were observed following exposures to increased concentrations of Microcystis, whilst Oscillatoria exposures only caused yolk sac edemas. Exposure to a high concentration of Microcystis induced severe oxidative damage, growth inhibition and transcriptional downregulations of genes (GH, GHR1, IGF1, IGF1rb) associated with the growth hormone/insulin-like growth factor (GH/IGF) axis. Although Oscillatoria exposure did not affect the body growth, it obviously enhanced the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and up-regulated the expressions of several oxidative stress-related genes. Discrepancies in the developmental toxicity caused by Microcystis and Oscillatoria may not only attributed to the different secondary metabolites they secrete, but also to the different adhesion behaviors of algal cells on embryonic chorion. These results suggested that harmful cyanobacteria cells could influence the successful recruitment of fish, while the effects of benthic cyanobacteria should not be ignored. It also highlighted that the necessity for further investigating the ecotoxicity of intact cyanobacterial samples when assessing the risk of cyanobacterial blooms.

Electrospun Nanofibers for Wound Dressing and Tissue Engineering Applications

Electrospinning has received tremendous attention in the fabrication of nanofibrous scaffolds over recent years and employed in different biomedical applications because of their biomimetic nature. Especially, the electrospun nanofibers exhibit several beneficial features including natural extracellular matrix (ECM), interconnected pores, large surface area, ease of functionalization and mechanical performance that holds huge importance in influencing the cell adhesion, differentiation and proliferation behaviour. To date, acknowledging the wide range of beneficial features, the electrospun nanofibers have been used in wound dressing and tissue engineering applications. This review summarizes various efforts have been made in these areas with several representative examples indicating use of various materials and approaches. Further the concerns for future direction regard to clinical phase transfer has been discussed.

Surface Characteristics and Cell Adhesion Behaviors of the Anodized Biomedical Stainless Steel

In this study, an electrochemical anodizing method was applied as surface modification of the 316L biomedical stainless steel (BSS). The surface properties, microstructural characteristics, and biocompatibility responses of the anodized 316L BSS specimens were elucidated through scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, transmission electron microscopy, and in vitro cell culture assay. Analytical results revealed that the oxide layer of dichromium trioxide (Cr2O3) was formed on the modified 316L BSS specimens after the different anodization modifications. Moreover, a dual porous (micro/nanoporous) topography can also be discovered on the surface of the modified 316L BSS specimens. The microstructure of the anodized oxide layer was composed of amorphous austenite phase and nano-Cr2O3. Furthermore, in vitro cell culture assay also demonstrated that the osteoblast-like cells (MG-63) on the anodized 316L BSS specimens were completely adhered and covered as compared with the unmodified 316L BSS specimen. As a result, the anodized 316L BSS with a dual porous (micro/nanoporous) oxide layer has great potential to induce cell adhesion and promote bone formation.

Multifunctional-imprinted nanocomposite membranes with thermo-responsive biocompatibility for selective/controllable recognition and separation application

Inspired by the biomimetic modification strategy of dopamine self-polymerization technique, molecularly imprinted nanocomposite membranes (MINCMs) with thermo-responsive rebinding and separation performance were synthesized and evaluated. Herein, the Au/SiO2-based multilevel structure had been successfully obtained onto the polydopamine (pDA) modified membrane surfaces. Afterward, the poly(N-isopropylacrylamide)-based biomolecule-imprinted sites were adequately constructed by developing a photoinitiated atom transfer radical polymerization (pATRP) imprinting strategy using the high-biocompatible ovalbumin (Ova, pI 4.6) as template molecule. Therefore, thermo-responsive ‘specific recognition sites’ toward Ova were then achieved on the as-prepared MINCMs after the well-designed imprinting process. When the external temperature was set at 37 °C, excellent ovalbumin rebinding capacity (33.26 mg/g), selectivity factor (3.06) and structural stability were obtained. Importantly, as to the controllable biocompatibility research of this work, the bare glass and Ova-bound-MINCMs (the MINCMs were bound with Ova) showed basically the same cell adhesion behaviors and viability, indicating the excellent biocompatibility of the Ova-bound-MINCMs. Additionally, efficient and rapid regulation of cell adhesion/detachment on ovalbumin-bound MINCMs could be still obtained even after 10 cycles of temperature-switch process, which indicated that the as-prepared MINCMs had strong ability to work under high intensity and long continuous operation.

Thermoresponsive Cationic Block Copolymer Brushes for Temperature-Modulated Stem Cell Separation.

Recently, cell separation methods have become important for preparing cells for transplantation therapy. In this study, a thermoresponsive cationic block copolymer brush is developed as an effective cell separation tool. This brush is prepared on glass surfaces using two steps of activator regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP). The cationic segment is prepared in the first step of the ARGET-ATRP of N,N-dimethylaminopropylacrylamide (DMAPAAm). In the second step, the thermoresponsive segment is prepared, attached to the bottom cationic segment, through ARGET-ATRP with N-isopropylacrylamide (NIPAAm). The cell adhesion behavior of the prepared thermoresponsive cationic copolymer, PDMAPAAm-b-PNIPAAm, brush is observed using umbilical cord-derived mesenchymal stem cells (UCMSC), fibroblasts, and macrophages. At 37 °C, all three types of cells adhere to the thermoresponsive cationic copolymer brush. Then, by reducing the temperature to 20 °C, the adhered UCMSC are detached from the copolymer brush, whereas the fibroblasts and macrophages remain adhered to the copolymer brush. Using this copolymer brush, UCMSC can be purified from the cell mixture simply by changing the temperature. Therefore, the prepared thermoresponsive cationic copolymer brush is useful as a cell separation tool for the purification of mesenchymal stem cells.

The Hyaluronan Pericellular Coat and Cold Atmospheric Plasma Treatment of Cells

In different tumors, high amounts of hyaluronan (HA) are correlated with tumor progression. Therefore, new tumor therapy strategies are targeting HA production and degradation. In plasma medicine research, antiproliferative and apoptosis-inducing effects on tumor cells were observed using cold atmospheric plasma (CAP) or plasma-activated media (PAM). Until now, the influence of PAM on the HA pericellular coat has not been the focus of research. PAM was generated by argon-plasma treatment of Dulbecco’s modified Eagle’s Medium via the kINPen®09 plasma jet. The HA expression on PAM-treated HaCaT cells was determined by flow cytometry and confocal laser scanning microscopy. Changes in the adhesion behavior of vital cells in PAM were observed by impedance measurement using the xCELLigence system. We found that PAM treatment impaired the HA pericellular coat of HaCaT cells. The time-dependent adhesion was impressively diminished. However, a disturbed HA coat alone was not the reason for the inhibition of cell adhesion because cells enzymatically treated with HAdase did not lose their adhesion capacity completely. Here, we showed for the first time that the plasma-activated medium (PAM) was able to influence the HA pericellular coat.

Protein adsorption and cell adhesion behavior of engineering plastics plasticized by supercritical carbon dioxide.

We aimed to evaluate the biological properties of engineering plastics (PC, PSU, PAR) processed using supercritical carbon dioxide (scCO2). Conventional mold process was used to prepare disk-shaped samples that were then plasticized by scCO2 at temperatures lower than the glass transition temperature (Tg) of the polymers. Surface roughness, contact angle, and amount of adsorbed protein on the surface were increased after treatment. The surface roughness of PC was significantly changed by scCO2 treatment. Cell adhesion and proliferation changed according to the differences in surface roughness. Initially, the cell adhesion decreased in all scCO2-treated polymers. At 3 day, the cell proliferation on scCO2-treated PC was lower than that on non-treated PC, while that on treated and non-treated PSU and PAR samples remained unaltered. These results suggest that when supercritical treatment is performed under conditions that affect the surface properties of the material, we should consider that cell adhesion and proliferation may change.

CAD/CAM scaffolds for bone tissue engineering: investigation of biocompatibility of selective laser melted lightweight titanium.

The objective of the current in-vitro study was to evaluate the biocompatibility of a new type of CAD/CAM scaffold for bone tissue engineering by using human cells. Porous lightweight titanium scaffolds and Bio-Oss® scaffolds as well as their eluates were used for incubation with human osteoblasts, fibroblasts and osteosarcoma cells. The cell viability was assessed by using fluorescein diazo-acetate propidium iodide staining. Cell proliferation and metabolism was examined by using MTT-, WST-Test and BrdU-ELISA tests. Scanning electron microscope was used for investigation of the cell adhesion behaviour. The number of devitalised cells in all treatment groups did not significantly deviate from the control group. According to MTT and WST results, the number of metabolically active cells was decreased by the eluates of both test groups with a more pronounced impact of the eluate from Bio-Oss®. The proliferation of the cells was inhibited by the addition of the eluates. Both scaffolds showed a partial surface coverage after 1 week and an extensive to complete coverage after 3 weeks. The CAD/CAM titanium scaffolds showed favourable biocompatibility compared to Bio-Oss® scaffolds in vitro. The opportunity of a defect-specific design and rapid prototyping by selective laser melting are relevant advantages in the field of bone tissue engineering and regenerative medicine.