Micropattern-controlled chirality of focal adhesions regulates the cytoskeletal arrangement and gene transfection of mesenchymal stem cells

Effectively Guiding Cell Elongation and Alignment by Constructing Micro/Nano Hierarchical Patterned Titania on Titanium Substrate

Based on the innate sensitivity of cell to substrate topographical cues, modulating cell-directed growth behavior is crucial for promoting tissue repair and reconstruction. Although photolithography technology has been extensively employed to fabricate a variety of anisotropic patterned structures to guide cell growth, it remains a great challenge to design high-resolution micro/nano hierarchical structures directly onto medical titanium (Ti)-based implants. Herein, we present a rapid, reliable and reproducible approach combining photolithography and hydrothermal technology to construct a micro/nano hierarchical structure including anisotropic micro-strips and a porous structure composed of TiO2 nanotubes features. In vitro biological and physicochemical analyses revealed that the micro/nano hierarchical structures not only efficiently facilitate the localization and adsorption of BSA molecules, but also enhances the control of cell growth behavior. The synergistic effect between the physical limitation for organizing cellular cytoskeleton at micropattern and the control of focal adhesion sits at the nanoscale can effectively guide cells to maintain stable elongation and alignment, even at large micro-stripe width of 100 μm. This study presents a promising strategy to precisely construct micro/nano multi-level patterned structure on Ti substrate using biomaterials with excellent biocompatibility. These functional micro/nano hybrid micropatterns offer a powerful platform for regulating bioreagent localization and cell behaviors in various applications including tissue engineering, regenerative medicine, drug screening, and biosensors.

Improved Cell Adhesion on Self-Assembled Chiral Nematic Cellulose Nanocrystal Films

Chirality is ubiquitous in nature, and closely related to biological phenomena. Nature-originated nanomaterials such as cellulose nanocrystals (CNCs) are able to self-assemble into hierarchical chiral nematic CNC films and impart handedness to nano and micro scale. However, the effects of the chiral nematic surfaces on cell adhesion are still unknown. Herein, this work presents evidence that the left-handed self-assembled chiral nematic CNC films (L-CNC) significantly improve the adhesion of L929 fibroblasts compared to randomly arranged isotropic CNC films (I-CNC). The fluidic force microscopy-based single-cell force spectroscopy is introduced to assess the cell adhesion forces on the substrates of L-CNC and I-CNC, respectively. With this method, a maximum adhesion force of 133.2 nN is quantified for mature L929 fibroblasts after culturing for 24 h on L-CNC, whereas the L929 fibroblasts exert a maximum adhesion force of 78.4 nN on I-CNC under the same condition. Moreover, the instant SCFS reveals that the integrin pathways are involved in sensing the chirality of substrate surfaces. Overall, this work offers a starting point for the regulation of cell adhesion via the self-assembled nano and micro architecture of chiral nematic CNC films, with potential practical applications in tissue engineering and regenerative medicine.

Advanced Microarrays as Heterogeneous Force-Remodeling Coordinator to Orchestrate Nuclear Configuration and Force-Sensing Mechanotransduction in Stem Cells

Integrin and focal adhesion can regulate cytoskeleton distribution to govern actin-related force remodeling and play an important role in nuclear configuration and force-sensing mechanotransduction of stem cells. However, further exploration of the interaction between actinin complex and myosin, kinetics, and molecular mechanism of cytoskeleton structures to nucleate within the engineered stem cells is vague. An extensive comprehension of cell morphogenesis, force remodeling, and nuclear force-sensing mechanotransduction is essential to reveal the basic physical principles of cytoskeleton polymerization and force-related signaling delivery. Advanced microarrays are designed to determine heterogeneous cell morphology and cell adhesion behaviors in stem cells. The heterogeneity from the engineered microarrays is transferred into nuclei to regulate nuclear configuration and force-sensing mechanotransduction by the evaluation of Lamins, YAP, and BrdU expression. Tuning the activation of adhesion proteins and cytoskeleton nucleators to adjust heterogeneous cell mechanics may be the underlying mechanism to change nuclear force-sensing configuration in response to its physiological mechanotransduction in microarrayed stem cells.

Heterogeneous focal adhesion cytoskeleton nanoarchitectures from microengineered interfacial curvature to oversee nuclear remodeling and mechanotransduction of mesenchymal stem cells

BACKGROUND

Interfacial heterogeneity is widely explored to reveal molecular mechanisms of force-mediated pathways due to biased tension. However, the influence of cell density,, curvature, and interfacial heterogeneity on underlying pathways of mechanotransduction is obscure.

METHODS

Polydimethylsiloxane (PDMS)-based stencils were micropatterned to prepare the micropores for cell culture. The colonies of human mesenchymal stem cells (hMSCs) were formed by controlling cell seeding density to investigate the influences of cell density, curvature and heterogeneity on mechanotransduction. Immunofluorescent staining of integrin, vinculin, and talin-1 was conducted to evaluate adhesion-related expression levels. Then, immunofluorescent staining of actin, actinin, and myosin was performed to detect cytoskeleton distribution, especially at the periphery. Nuclear force-sensing mechanotransduction was explained by yes-associated protein (YAP) and laminA/C analysis.

RESULTS

The micropatterned colony of hMSCs demonstrated the coincident characters with engineered micropores of microstencils. The cell colony obviously developed the heterogeneous morphogenesis. Heterogeneous focal adhesion guided the development of actin, actinin, and myosin together to regulate cellular contractility and movement by integrin, vinculin, and talin-1. Cytoskeletal staining showed that actin, actinin, and myosin fibers were reorganized at the periphery of microstencils. YAP nuclear translocation and laminA/C nuclear remodeling were enhanced at the periphery by the regulation of heterogeneous focal adhesion (FA) and cytoskeleton arrangement.

CONCLUSIONS

The characters of the engineered clustering colony showed similar results with prepared microstencils, and colony curvature was also well adjusted to establish heterogeneous balance at the periphery of cell colony. The mechanism of curvature, spreading, and elongation was also investigated to disclose the compliance of FA and cytoskeleton along with curvature microarrays for increased nuclear force-sensing mechanotransduction. The results may provide helpful information for understanding interfacial heterogeneity and nuclear mechanotransduction of stem cells.

Biofunctionalized patterned platform as microarray biochip to supervise delivery and expression of pDNA nanolipoplexes in stem cells via mechanotransduction

Biochips are widely applied to manipulate the geometrical morphology of stem cells in recent years. Patterned antenna-like pseudopodia are also probed to explore the influence of pseudopodia formation on gene delivery and expression on biochips. However, how the antenna-like pseudopodia affect gene transfection is unsettled and the underlying trafficking mechanism of exogenous genes in engineered single cells is not announced. Therefore, the engineered microarray biochips were conceptualized and prepared by the synthesized photointelligent biopolymer to precisely manage geometric topological structures (cell size and antenna-like protrusion) of stem cells on biochips. The cytoskeleton could be regulated in engineered cells and large cells with more antennas assembled well-organized actin filaments to affect cell tension distribution. The stiffness and adhesion force were measured by atomic force microscope to reveal cell nanomechanics on microarray biochips. Cytoskeleton-mediated nanomechanics could be adjusted by actin filaments. Gene transfection efficiency was enhanced with increasing cell nanomechanics, which was also confirmed by the evaluation of cell internalization capacity of nanoparticles and DNA synthesis ability. This work will provide a new strategy to study functional biomaterials, microarray chips and internal mechanism of gene transfection in patterned stem cells on biochips.

Chiral Engineered Biomaterials: New Frontiers in Cellular Fate Regulation for Regenerative Medicine

Chirality, the property of objects that are nonsuperimposable on their mirror images, plays a crucial role in biological processes and cellular behaviors. Chiral engineered biomaterials have emerged as a promising approach to regulating cellular fate in regenerative medicine. However, few reviews provide a comprehensive examination of recent advancements in chiral biomaterials and their applications in cellular fate regulation. Herein, various fabrication techniques available for chiral biomaterials, including the use of chiral molecules, surface patterning, and self‐assembly are discussed. The mechanisms through which chiral biomaterials influence cellular responses, such as modulation of adhesion receptors, intracellular signaling, and gene expression, are explored. Notably, chiral biomaterials have demonstrated their ability to guide stem cell differentiation and augment tissue‐specific functions. The potential applications of chiral biomaterials in musculoskeletal disorders, neurodegenerative diseases, cardiovascular diseases, and wound healing are highlighted. Challenges and future perspectives, including standardization of fabrication methods and translation to clinical settings, are addressed. In conclusion, chiral engineered biomaterials offer exciting prospects for precisely controlling cellular fate, advancing regenerative medicine, and enabling personalized therapeutic strategies.

Force-sensing protein expression in response to cardiovascular mechanotransduction

Force-sensing biophysical cues in microenvironment, including extracellular matrix performances, stretch-mediated mechanics, shear stress and flow-induced hemodynamics, have a significant influence in regulating vascular morphogenesis and cardiac remodeling by mechanotransduction. Once cells perceive these extracellular mechanical stimuli, Piezo activation promotes calcium influx by forming integrin-adhesion-coupling receptors. This induces robust contractility of cytoskeleton structures to further transmit biomechanical alternations into nuclei by regulating Hippo-Yes associated protein (YAP) signaling pathway between cytoplasmic and nuclear translocation. Although biomechanical stimuli are widely studied in cardiovascular diseases, the expression of force-sensing proteins in response to cardiovascular mechanotransduction has not been systematically concluded. Therefore, this review will summarize the force-sensing Piezo, cytoskeleton and YAP proteins to mediate extracellular mechanics, and also give the prominent emphasis on intrinsic connection of these mechanical proteins and cardiovascular mechanotransduction. Extensive insights into cardiovascular mechanics may provide some new strategies for cardiovascular clinical therapy.

Biomimetic concentric microgrooved titanium surfaces influence bone marrow-derived mesenchymal stem cell osteogenic differentiation via H3K4 trimethylation epigenetic regulation

Material surface micromorphology can modulate cellular behavior and promote osteogenic differentiation through cytoskeletal rearrangement. Bone reconstruction requires precise regulation of gene expression in cells, a process governed by epigenetic mechanisms such as histone modifications, DNA methylation, and chromatin remodeling. We constructed osteon-mimetic concentric microgrooved titanium surfaces with different groove sizes and cultured bone marrow-derived mesenchymal stem cells (BMSCs) on the material surfaces to study how they regulate cell biological behavior and osteogenic differentiation through epigenetics. We found that the cells arranged in concentric circles along the concentric structure in the experimental group, and the concentric microgrooved surface did not inhibit cell proliferation. The results of a series of osteogenic differentiation experiments showed that the concentric microgrooves facilitated calcium deposition and promoted osteogenic differentiation of the BMSCs. Concentric microgrooved titanium surfaces that were 30 μm wide and 10 μm deep promoted osteogenic differentiation of BMSC by increasing WDR5 expression via H3K4 trimethylation upregulation.

Focal adhesion and actin orientation regulated by cellular geometry determine stem cell differentiation via mechanotransduction

Tuning cell adhesion geometry can affect cytoskeleton organization and the distribution of cytoskeleton forces, which play critical roles in controlling cell functions. To elucidate the geometrical relationship with cytoskeleton force distribution, it is necessary to control cell morphology. In this study, a series of dextral vortex micropatterns were prepared to precisely control cell morphology for investigating the influence of the curvature degree of adhesion curves on intracellular force distribution and stem cell differentiation at a sub-cellular level. Peripherial actin filaments of micropatterned cells were assembled along the adhesion curves and showed different orientations, filament thicknesses and densities. Focal adhesion and cytoskeleton force distribution were dependent on the curvature degree. Intracellular force distribution was also regulated by adhesion curves. The cytoskeleton and force distribution affected the osteogenic differentiation of mesenchymal stem cells through a YAP/TAZ-mediated mechanotransduction process. Thus, regulation of cell adhesion curvature, especially at cytoskeletal filament level, is critical for cell function manipulation. STATEMENT OF SIGNIFICANCE: In this study, a series of dextral micro-vortexes were prepared and used for the culture of human mesenchymal stem cells (hMSCs) to precisely control adhesive curvatures (0°, 30°, 60°, and 90°). The single MSCs on the micropatterns had the same size and shape but showed distinct focal adhesion (FA) and cytoskeleton orientations. Cellular nanomechanics were observed to be correlated with the curvature degrees, subsequently influencing nuclear morphological features. As a consequence, the localization of the mechanotransduction sensor and activator-YAP/TAZ was affected, influencing osteogenic differentiation. The results revealed the pivotal role of adhesive curvatures in the manipulation of stem cell differentiation via the machanotransduction process, which has rarely been investigated.

Amino acid-based supramolecular chiral hydrogels promote osteogenesis of human dental pulp stem cells via the MAPK pathway

Critical-size defects (CSDs) of the craniofacial bones cause aesthetic and functional complications that seriously impact the quality of life. The transplantation of human dental pulp stem cells (hDPSCs) is a promising strategy for bone tissue engineering. Chirality is commonly observed in natural biomolecules, yet its effect on stem cell differentiation is seldom studied, and little is known about the underlying mechanism. In this study, supramolecular chiral hydrogels were constructed using L/d-phenylalanine (L/D-Phe) derivatives. The results of alkaline phosphatase expression analysis, alizarin red S assay, as well as quantitative real-time polymerase chain reaction and western blot analyses suggest that right-handed D-Phe hydrogel fibers significantly promoted osteogenic differentiation of hDPSCs. A rat model of calvarial defects was created to investigate the regulation of chiral nanofibers on the osteogenic differentiation of hDPSCs in vivo. The results of the animal experiment demonstrated that the D-Phe group exhibited greater and faster bone formation on hDPSCs. The results of RNA sequencing, vinculin immunofluorescence staining, a calcium fluorescence probe assay, and western blot analysis indicated that L-Phe significantly promoted adhesion of hDPSCs, while D-Phe nanofibers enhanced osteogenic differentiation of hDPSCs by facilitating calcium entry into cells and activate the MAPK pathway. These results of chirality-dependent osteogenic differentiation offer a novel therapeutic strategy for the treatment of CSDs by optimising the differentiation of hDPSCs into chiral nanofibers.

Chiral Cell Nanomechanics Originated in Clockwise/Counterclockwise Biofunctional Microarrays to Govern the Nuclear Mechanotransduction of Mesenchymal Stem Cells

Cell chirality is extremely important for the evolution of cell morphogenesis to manipulate cell performance due to left-right asymmetry. Although chiral micro- and nanoscale biomaterials have been developed to regulate cell functions, how cell chirality affects cell nanomechanics to command nuclear mechanotransduction was ambiguous. In this study, chiral engineered microcircle arrays were prepared by photosensitive cross-linking synthesis on cell culture plates to control the clockwise/counterclockwise geometric topology of stem cells. Asymmetric focal adhesion and cytoskeleton structures could induce chiral cell nanomechanics measured by atomic force microscopy (AFM) nanoindentation in left-/right-handed stem cells. Cell nanomechanics could be enhanced when the construction of mature focal adhesion and the assembly of actin and myosin cytoskeletons were well organized in chiral engineered stem cells. Curvature angles had a negative effect on cell nanomechanics, while cell chirality did not change cytoskeletal mechanics. The biased cytoskeleton tension would engender different nuclear mechanotransductions by yes-associated protein (YAP) evaluation. The chiral stimuli were delivered into the nuclei to oversee nuclear behaviors. A strong cell modulus could activate high nuclear DNA synthesis activity by mechanotransduction. The results will bring the possibility of understanding the interplay of chiral cell nanomechanics and mechanotransduction in nanomedicines and biomaterials.

A PDA-Functionalized 3D Lung Scaffold Bioplatform to Construct Complicated Breast Tumor Microenvironment for Anticancer Drug Screening and Immunotherapy

2D cell culture occupies an important place in cancer progression and drug discovery research. However, it limitedly models the "true biology" of tumors in vivo. 3D tumor culture systems can better mimic tumor characteristics for anticancer drug discovery but still maintain great challenges. Herein, polydopamine (PDA)-modified decellularized lung scaffolds are designed and can serve as a functional biosystem to study tumor progression and anticancer drug screening, as well as mimic the tumor microenvironment. PDA-modified scaffolds with strong hydrophilicity and excellent cell compatibility can promote cell growth and proliferation. After 96 h treatment with 5-FU, cisplatin, and DOX, higher survival rates in PDA-modified scaffolds are observed compared to nonmodified scaffolds and 2D systems. The E-cadhesion formation, HIF-1α-mediated senescence decrease, and tumor stemness enhancement can drive drug resistance and antitumor drug screening of breast cancer cells. Moreover, there is a higher survival rate of CD45+ /CD3+ /CD4+ /CD8+ T cells in PDA-modified scaffolds for potential cancer immunotherapy drug screening. This PDA-modified tumor bioplatform will supply some promising information for studying tumor progression, overcoming tumor resistance, and screening tumor immunotherapy drugs.

3D micropattern force triggers YAP nuclear entry by transport across nuclear pores and modulates stem cells paracrine

Biophysical cues of the cellular microenvironment tremendously influence cell behavior by mechanotransduction. However, it is still unclear how cells sense and transduce the mechanical signals from 3D geometry to regulate cell function. Here, the mechanotransduction of human mesenchymal stem cells (MSCs) triggered by 3D micropatterns and its effect on the paracrine of MSCs are systematically investigated. Our findings show that 3D micropattern force could influence the spatial reorganization of the cytoskeleton, leading to different local forces which mediate nucleus alteration such as orientation, morphology, expression of Lamin A/C and chromatin condensation. Specifically, in the triangular prism and cuboid micropatterns, the ordered F-actin fibers are distributed over and fully transmit compressive forces to the nucleus, which results in nuclear flattening and stretching of nuclear pores, thus enhancing the nuclear import of YES-associated protein (YAP). Furthermore, the activation of YAP significantly enhances the paracrine of MSCs and upregulates the secretion of angiogenic growth factors. In contrast, the fewer compressive forces on the nucleus in cylinder and cube micropatterns cause less YAP entering the nucleus. The skin repair experiment provides the first in vivo evidence that enhanced MSCs paracrine by 3D geometry significantly promotes tissue regeneration. The current study contributes to understanding the in-depth mechanisms of mechanical signals affecting cell function and provides inspiration for innovative design of biomaterials.

Silk Fibroin-Based Tough Hydrogels with Strong Underwater Adhesion for Fast Hemostasis and Wound Sealing

Rapid and strong adhesion of hydrogel adhesives is required for instant wound closure and hemostasis. However, in situ hydrogel formation and sufficient adhesion at target tissue sites in biological environments are severely compromised by the presence of blood and body fluids. In this work, an underwater adhesive hydrogel (named SHCa) is fabricated with rapid in situ gelation, enhanced mechanical toughness, and robust underwater adhesion. The SHCa can undergo rapid UV irradiation-induced gelation under water within 5 s and adhere firmly to underwater surfaces for 6 months. The synergistic effects of crystalline β-sheet structures and dynamic energy-dissipating mechanisms enhance the mechanical toughness and cohesion, supporting the balance between adhesion and cohesion in wet environments. Importantly, the SHCa can achieve rapid in situ gelation and robust underwater adhesion at various tissue surfaces in highly dynamic fluid environments, substantially outperforming the commercially available tissue adhesives. The lap shear adhesion strength and wound closure strength of SHCa on blood-covered substrates are 7.24 and 12.68 times higher than those of cyanoacrylate glue, respectively. Its fast hemostasis and wound sealing performance are further demonstrated in in vivo animal models. The proposed hydrogel with strong underwater adhesion provides an effective tool for fast wound closure and hemostasis.

Regulation of micropatterned curvature-dependent FA heterogeneity on cytoskeleton tension and nuclear DNA synthesis of malignant breast cancer cells

Breast cancer is considered as a worldwide disease due to its high incidence and malignant metastasis. Although numerous techniques have been developed well to conduct breast cancer therapy, the influence of micropattern-induced interfacial heterogeneity on the molecular mechanism and nuclear signalling transduction of carcinogenesis is rarely announced. In this study, PDMS stencil-assisted micropatterns were fabricated on tissue culture plates to manage cell clustering colony by adjusting initial cell seeding density and the size of microholes. The curvature of each microholes was controlled to construct the interfacial heterogeneity of MDA-MB231 cancer cells at the periphery of micropatterned colony. The distinguished focal adhesion (FA) and cytoskeleton distribution at the central and peripheral regions of the cell colony were regulated by heterogeneous properties. The interfacial heterogeneity of FA and cytoskeleton would induce the biased tension force to encourage more ezrin expression at the periphery and further promote DNA synthesis, therefore disclosing a stem-like phenotype in heterogeneous cells. This study will provide a value source of information for the development of micropattern-induced heterogeneity and the interpretation of metastatic mechanism in malignant breast cancer cells.

Cellular nanomechanics derived from pattern-dependent focal adhesion and cytoskeleton to balance gene transfection of malignant osteosarcoma

Gene transfection was supposed to be the most promising technology to overcome the vast majority of diseases and it has been popularly reported in clinical applications of gene therapy. In spite of the rapid development of novel transfection materials and methods, the influence of morphology-dependent nanomechanics of malignant osteosarcoma on gene transfection is still unsettled. In this study, cell spreading and adhesion area was adjusted by the prepared micropatterns to regulate focal adhesion (FA) formation and cytoskeletal organization in osteosarcoma cells. The micropattern-dependent FA and cytoskeleton could induce different cellular nanomechanics to affect cell functions. Our results indicated that transfection efficiency was improved with enlarging FA area and cell nanomechanics in micropatterned osteosarcoma. The difference of gene transfection in micropatterned cells was vigorously supported by cellular internalization capacity, Ki67 proliferation ability and YAP mechanotranduction through the regulation of focal adhesion and cytoskeletal mechanics. This study is an attempt to disclose the relationship of cell nanomechanics and gene transfection for efficient gene delivery and develop multifunctional nanomedicine biomaterials for accurate gene therapy in osteosarcoma cells.

Promotion of Melanoma Cell Proliferation by Cyclic Straining through Regulatory Morphogenesis

The genotype and phenotype of acral melanoma are obviously different from UV-radiation-induced melanoma. Based on the clinical data, mechanical stimulation is believed to be a potential cause of acral melanoma. In this case, it is desirable to clarify the role of mechanical stimulation in the progression of acral melanoma. However, the pathological process of cyclic straining that stimulates acral melanoma is still unclear. In this study, the influence of cyclic straining on melanoma cell proliferation was analyzed by using a specifically designed cell culture system. In the results, cyclic straining could promote melanoma cell proliferation but was inefficient after the disruption of cytoskeleton organization. Therefore, the mechanotransduction mechanism of promoted proliferation was explored. Both myosin and actin polymerization were demonstrated to be related to cyclic straining and further influenced the morphogenesis of melanoma cells. Additionally, the activation of mechanosensing transcription factor YAP was related to regulatory morphogenesis. Furthermore, expression levels of melanoma-involved genes were regulated by cyclic straining and, finally, accelerated DNA synthesis. The results of this study will provide supplementary information for the understanding of acral melanoma.

Morphological Dependence of Breast Cancer Cell Responses to Doxorubicin on Micropatterned Surfaces

Cell morphology has been widely investigated for its influence on the functions of normal cells. However, the influence of cell morphology on cancer cell resistance to anti-cancer drugs remains unclear. In this study, micropatterned surfaces were prepared and used to control the spreading area and elongation of human breast cancer cell line. The influences of cell adhesion area and elongation on resistance to doxorubicin were investigated. The percentage of apoptotic breast cancer cells decreased with cell spreading area, while did not change with cell elongation. Large breast cancer cells had higher resistance to doxorubicin, better assembled actin filaments, higher DNA synthesis activity and higher expression of P-glycoprotein than small breast cancer cells. The results suggested that the morphology of breast cancer cells could affect their resistance to doxorubicin. The influence was correlated with cytoskeletal organization, DNA synthesis activity and P-glycoprotein expression.

Influence of Colonies’ Morphological Cues on Cellular Uptake Capacity of Nanoparticles

High transmembrane delivery efficiency of nanoparticles has attracted substantial interest for biomedical applications. It has been proved that the desired physicochemical properties of nanoparticles were efficient for obtaining a high cellular uptake capacity. On the other hand, biophysical stimuli from in situ microenvironment were also indicated as another essential factor in the regulation of cellular uptake capacity. Unfortunately, the influence of colony morphology on cellular uptake capacity was rarely analyzed. In this study, micropatterned PDMS stencils containing circular holes of 800/1,200 μm in diameter were applied to control colonies’ size. The amino-modified nanoparticles were cocultured with micropatterned colonies to analyze the influence of colonies’ morphology on the cellular uptake capacity of nanoparticles. Consequently, more endocytosed nanoparticles in larger colonies were related with a bigger dose of nanoparticles within a larger area. Additionally, the high cell density decreased the membrane–nanoparticles’ contacting probability but enhanced clathrin-mediated endocytosis. With these contrary effects, the cells with medium cell density or located in the peripheral region of the micropatterned colonies showed a higher cellular uptake capacity of nanoparticles.

Pillar-Based Mechanical Induction of an Aggressive Tumorigenic Lung Cancer Cell Model

Tissue microarchitecture imposes physical constraints to the migration of individual cells. Especially in cancer metastasis, three-dimensional structural barriers within the extracellular matrix are known to affect the migratory behavior of cells, regulating the pathological state of the cells. Here, we employed a culture platform with micropillar arrays of 2 μm diameter and 16 μm pitch (2.16 micropillar) as a mechanical stimulant. Using this platform, we investigated how a long-term culture of A549 human lung carcinoma cells on the (2.16) micropillar-embossed dishes would influence the pathological state of the cell. A549 cells grown on the (2.16) micropillar array with 10 μm height exhibited a significantly elongated morphology and enhanced migration even after the detachment and reattachment, as evidenced in the conventional wound-healing assay, single-cell tracking analysis, and in vivo tumor colonization assays. Moreover, the pillar-induced morphological deformation in nuclei was accompanied by cell-cycle arrest in the S phase, leading to suppressed proliferation. While these marked traits of morphology-migration-proliferation support more aggressive characteristics of metastatic cancer cells, typical indices of epithelial-mesenchymal transition were not found, but instead, remarkable traces of amoeboidal transition were confirmed. Our study also emphasizes the importance of mechanical stimuli from the microenvironment during pathogenesis and how gained traits can be passed onto subsequent generations, ultimately affecting their pathophysiological behavior. Furthermore, this study highlights the potential use of pillar-based mechanical stimuli as an in vitro cell culture strategy to induce more aggressive tumorigenic cancer cell models.

Tumor-targeting biomimetic sonosensitizer-conjugated iron oxide nanocatalysts for combinational chemodynamic-sonodynamic therapy of colorectal cancer

Nanoparticle-based tumor therapy strategies have been widely developed, while the therapeutic efficacy is often limited due to poor accumulation of nanoparticles in tumor tissues and low antitumor effect of sole...

Influences of Viscosity on the Osteogenic and Adipogenic Differentiation of Mesenchymal Stem Cells with Controlled Morphology

Matrix viscoelastic properties have been shown to have important effects on cell functions. However, the conventional culture methods for investigating the influences of viscoelastic properties on cell functions cannot exclude...

The osteogenic response to chirality-patterned surface potential distribution of CFO/P(VDF-TrFE) membranes

Piezoelectric poly(vinylidene fluoride-trifluoroethylene) has demonstrated an ability to promote osteogenesis, and the biomaterials with a chirality-patterned topological surface could enhance cellular osteogenic differentiation. In this work, we created a chirality-patterned...

Laminin-511 and recombinant vitronectin supplementation enables human pluripotent stem cell culture and differentiation on conventional tissue culture polystyrene surfaces in xeno-free conditions

Human pluripotent stem cells (hPSCs) are typically cultivated on extracellular matrix (ECM) protein-coated dishes in xeno-free culture conditions. We supplemented mixed ECM proteins (laminin-511 and recombinant vitronectin, rVT) in culture medium for hPSC culture on conventional polystyrene dishes. Three hPSC cell lines were successfully cultivated on uncoated polystyrene dishes in medium supplemented with optimal conditions of laminin-511 and rVT. Excellent colony shape and colony size as well as high expansion fold of hPSCs were found under these conditions, whereas the colony size was small and poor expansion fold was found solely on L-511-coated dishes. A small portion of L-511 in the culture medium supported hPSC adhesion and prevented the adhesion from being too strong on the uncoated dishes, and rVT in the culture medium further supported adhesion of hPSCs on the dishes by maintaining their pluripotency. Having the optimal composition of L-511 and rVT in the culture medium was important for generating good hPSC colony shapes and sizes as well as a high expansion fold. After long-term culture of hPSCs on uncoated dishes supplemented with the mixed proteins, the hPSCs successfully showed pluripotent markers and could differentiate into a specific lineage of cells, cardiomyocytes, with high efficiency.

Poly(vinyl alcohol-co-itaconic acid) hydrogels grafted with several designed peptides for human pluripotent stem cell culture and differentiation into cardiomyocytes

We developed poly(vinyl alcohol-co-itaconic acid) (PV) hydrogels grafted with laminin-derived peptides that had different joint segments and several specific designs, including dual chain motifs. PV hydrogels grafted with a peptide derived from laminin-β4 (PMQKMRGDVFSP) containing a joint segment, dual chain motif and cationic amino acid insertion could attach human pluripotent stem (hPS) cells and promoted high expansion folds in long-term culture (over 10 passages) with low differentiation rates, whereas hPS cells attached poorly on PV hydrogels grafted with laminin-α5 peptides that had joint segments with and without a cationic amino acid or on PV hydrogels grafted with laminin-β4 peptides containing the joint segment only. The inclusion of a cationic amino acid in the laminin-β4 peptide was critical for hPS cell attachment on PV hydrogels, which contributed to the zeta potential shifting to higher values (3-4 mV enhancement). The novel peptide segment-grafted PV hydrogels developed in this study supported hPS cell proliferation, which induced better hPS cell expansion than recombinant vitronectin-coated dishes (gold standard of hPS cell culture dishes) in xeno-free culture conditions. After long-term culture on peptide-grafted hydrogels, hPS cells could be induced to differentiate into specific lineages of cells, such as cardiomyocytes, with high efficiency.

Regulation of gene transfection by cell size, shape and elongation on micropatterned surfaces

Gene transfection has been widely studied due to its potential applications in tissue repair and gene therapy. Many studies have focused on designing gene carriers and developing novel transfection techniques. However, the influence of cell size, shape and elongation on gene transfection has rarely been investigated. In this study, poly(vinyl alcohol)-micropatterned surfaces were prepared to precisely manipulate the size, shape and elongation of mesenchymal stem cells, and the influences of these factors on gene transfection were investigated. Cell size showed a significant influence on gene transfection. Elongation could affect the gene transfection of large cells but not small cells. Cells with a large spreading area and high aspect ratio showed high transfection with exogenous plasmid DNA. In particular, the transfection efficiency was the highest in micropatterned cells with a spreading area of 5024 μm2 and an aspect ratio of 8 : 1. In contrast, cell shape had no significant influence on gene transfection. The different influences of cell size, shape and elongation were correlated with their respective impacts on cytoskeletal structures, cellular nanoparticle uptake and DNA synthesis. Cells with a large size and elongated morphology showed well-organized actin filaments with a high cellular modulus, therefore promoting cellular nanoparticle uptake and DNA synthesis. Cells with different shapes showed similarities in actin filament organization, cellular modulus, uptake capacity and DNA synthesis. The results suggest the importance of cell size and elongation in exogenous gene transfection and should provide useful information for gene transfection and gene therapy.