A Review of Cell Adhesion Studies for Biomedical and Biological Applications

Polyimide biocomposites coated with tantalum pentoxide for stimulation of cell compatibility and enhancement of biointegration for orthopedic implant

Orthopedic implants are an important tool in the treatment of musculoskeletal conditions and helped many patients to improve their quality of life. Various inorganic-organic biocomposites have been broadly investigated particularly in the area of load-bearing orthopedic/dental applications. Polyimide (PI) is a promising organic material and shows excellent mechanical properties, biocompatibility, bio-stability, and its elastic modulus is similar to human bone but it lacks bioactivity, which is very important for cell adhesion and ultimately for bone regeneration. In this research, tantalum pentoxide (Ta2O5) coating was prepared on the surface of PI by polydopamine (PDA) bonding. The results showed that Ta2O5 was evenly coated on the surface of PI, and with the concentration of Ta2O5 in the PDA suspension increased, the content of Ta2O5 particles on the surface of PI increased significantly. In addition, the Ta2O5 coating significantly increased the roughness and hydrophilicity of the PI matrix. Cell experiments showed that PI surface coating Ta2O5 could promote the proliferation, adhesion, and osteogenic differentiation of bone marrow-derived stromal cells (BMSCs). The results demonstrated that fabricating Ta2O5 coating on the surface of PI through PDA bonding could improve the biocompatibility as well as bioactivity of PI, and increase the application potential of PI in the field of bone repair materials.

Fabrication of hydrophilic polymer-hybrid octacalcium phosphate blocks under wet condition based on cement setting reactions

Bioceramics, while offering excellent biocompatibility, are often compromised by their fragility and brittleness, especially under wet conditions. Even though recent hybrid processes combining biocompatible polymers and bioceramics have shown promise, complete mitigation of these challenges remains elusive. In this research, a biomimetic process was employed to mimic the structure of biological bone tissue. This led to the development of block materials composed of octacalcium phosphate (OCP) and sodium polyacrylic acid (PAA-Na) that display flexibility and resilience in wet conditions. Adjusting the PAA-Na concentration enabled the OCP-PAA-Na blocks to demonstrate superior mechanical strength when dry and increased flexibility when wet. Notably, these blocks expanded in aqueous solutions while preserving their structure, making them ideal for oral surgeries by preventing issues like blood flooding from implanted areas.

A novel observation: effect of anionic gelatin nanoparticle on stromal cells

Biocompatible nanoparticles are very popular in health science research. Biomolecule carriers for wound healing and tissue engineering are two main applications among many others. In many instances, these structures come in direct vicinity of cells and govern cell behaviour and responses. In this study, gelatin nano/submicron structures were synthesized by binary nonsolvent aided coacervation (BNAC) method at pH ranging from 3 to 11 with an intention to employ in skin tissue regeneration. Effect of pH over morphology and the surface composition with respect to its ionic composition were studied. Further, the initial toxicity was assessed against peripheral blood mononuclear cells (PBMC). pH 7 was found to be the optimum for synthesis of gelatin nanoparticles (GNPs) with minimum particle size. Positive cell viability of 103.14% for GNPs synthesized at pH 7 was observed. It may be due to the minimum difference between cumulative negative and positive charge (CNCP) ratio of 1.19. Finally, effect of the gelatin nanoparticles over L929 mouse fibroblast cells was assessed through MTT assay. It has resulted in 122.77% cell viability.

Development of cultivable alginate fibers for an ideal cell-cultivated meat scaffold and production of hybrid cultured meat

Slaughtering animals for meat pose several challenges, including environmental pollution and ethical concerns. Scaffold-based cell-cultivated meat has been proposed as a solution to these problems, however, the utilization of animal-derived materials for scaffolding or the high cost of production remains a significant challenge. Alginate is an ideal material for cell-cultivated meat scaffolds but has poor cell adhesion properties. To address this issue, we achieved 82 % cell adhesion coverage by controlling the specific structure generated during the ionic crosslinking process of alginate. Post 11 days of culture; we evaluated cell adhesion, differentiation, and aligned cell networks. The cell growth increased by 12.7 % compared to the initial seeding concentration. Finally, we created hybrid cell-cultivated meat by combining single-cell protein from mycelium and cell-cultivated meat. This is non-animal based, edible, cost-effective, and has a desirable texture by blending cell-cultivated meat with a meat analogue. In summary, the creation of improved alginate fibers can effectively tackle various obstacles encountered in the manufacturing of cell-cultivated meat. This includes enhancing cell adhesion, reducing costs, and streamlining the production procedure.

In Vitro Inhibitory Potential of Different Anthocyanin-Rich Berry Extracts in Murine CT26 Colon Cancer Cells

Anti-oxidant, -inflammatory, and -carcinogenic activities of bioactive plant constituents, such as anthocyanins, have been widely discussed in literature. However, the potential interaction of anthocyanin-rich extracts with routinely used chemotherapeutics is still not fully elucidated. In the present study, anthocyanin-rich polyphenol extracts of blackberry (BB), bilberry (Bil), black currant (BC), elderberry (EB), and their respective main anthocyanins (cyanidin-3-O-glucoside, delphinidin-3-O-glucoside, cyanidin-3-O-rutinoside, and cyanidin-3-O-sambubioside) were investigated concerning their cytotoxic and DNA-damaging properties in murine CT26 cells either alone or in combination with the chemotherapeutic agent SN-38. BB exerted potent cytotoxic effects, while Bil, BC, and EB only had marginal effects on cell viability. Single anthocyanins comprised of the extracts could not induce comparable effects. Even though the BB extract further pronounced SN-38-induced cytotoxicity and inhibited cell adhesion at 100-200 µg/mL, no effect on DNA damage was observed. In conclusion, anti-carcinogenic properties of the extracts on CT26 cells could be ranked BB >> BC ≥ Bil ≈ EB. Mechanisms underlying the potent cytotoxic effects are still to be elucidated since the induction of DNA damage does not play a role.

Secondary Metabolites from Fungi Microsphaeropsis spp.: Chemistry and Bioactivities

Microsphaeropsis, taxonomically classified within the kingdom fungi, phylum Ascomycota, subphylum Deuteromycotina, class Coelomycetes, order Sphaeropsidales, and family Sphaeropsidaceae, exhibit a ubiquitous distribution across various geographical regions. These fungi are known for their production of secondary metabolites, characterized by both structural novelty and potent biological activity. Consequently, they represent a significant reservoir for the advancement of novel pharmaceuticals. In this paper, a systematic review was present, marking the analysis of secondary metabolites synthesized by Microsphaeropsis reported between 1980 and 2023. A total of 112 compounds, comprising polyketones, macrolides, terpenoids, and nitrogen-containing compounds, were reported from Microsphaeropsis. Remarkably, among these compounds, 49 are novel discoveries, marking a significant contribution to the field. A concise summary of their diverse biological activities was provided, including antibacterial, antitumor, and antiviral properties and other bioactivities. This analysis stands as a valuable reference, poised to guide further investigations into the active natural products derived from Microsphaeropsis and their potential contributions to the development of medicinal resources.

Liposome-loaded polymeric microneedles for enhanced skin deposition of rifampicin

Methicillin-resistant Staphylococcus aureus (MRSA) is a prevailing bacterial pathogen linked to superficial skin and soft tissue infections (SSTIs). Rifampicin (RIF), a potent antibiotic against systemic and localised staphylococcal infections, faces limitations due to its low solubility. This constraint hampers its therapeutic potential for MRSA-induced SSTIs. To address this, an advanced liposomal system was designed for efficient dermal RIF delivery. Rifampicin-loaded liposomes (LipoRIF) were embedded within polymeric dissolving microneedles (DMNs) to enable targeted intradermal drug delivery. A robust Design of Experiment (DoE) methodology guided the systematic preparation and optimisation of LipoRIF formulations. The optimal LipoRIF formulation integrated within polymeric DMNs. These LipoRIF-DMNs exhibited favourable mechanical properties and effective skin insertion characteristics. Notably, in vitro assays on skin deposition unveiled a transformative result - the DMN platform significantly enhanced LipoRIF deposition within the skin, surpassing LipoRIF dispersion alone. Moreover, LipoRIF-DMNs displayed minimal cytotoxicity toward cells. Encouragingly, rigorous in vitro antimicrobial evaluations demonstrated LipoRIF-DMNs' capacity to inhibit MRSA growth compared to the control group. LipoRIF-DMNs propose a potentially enhanced, minimally invasive approach to effectively manage SSTIs and superficial skin ailments stemming from MRSA infections.

Modulating pro-adhesive nature of metallic surfaces through a polypeptide coupling via diazonium chemistry

The design of biomaterials able to facilitate cell adhesion is critical in the field of tissue engineering. Precise control of surface chemistry at the material/tissue interface plays a major role in enhancing the interactions between a biomaterial and living cells. Bio-integration is particularly important in case of various electrotherapies, since a close contact between tissue and electrode's surface facilitates treatment. A promising approach towards surface biofunctionalization involves the electrografting of diazonium salts followed by the modification of organic layer with pro-adhesive polypeptides. This study focuses on the modification of platinum electrodes with a 4-nitrobenzenediazonium layer, which is then converted to the aminobenzene moiety. The electrodes are further biofunctionalized with polypeptides (polylysine and polylysine/laminin) to enhance cell adhesion. This study also explores the differences between physical and chemical coupling of selected polypeptides to modulate pro-adhesive nature of Pt electrodes with respect to human neuroblastoma SH-SY5Y cells and U87 astrocytes. Our results demonstrate the significant enhancement in cell adhesion for biofunctionalized electrodes, with more amplified adhesion noted for covalently coupled polypeptides. The implications of this research are crucial for the development of more effective and functional biomaterials, particularly biomedical electrodes, which have the potential to advance the field of bioelectronics and improve patients' outcomes.

Replication of natural surface topographies to generate advanced cell culture substrates

Surface topographies of cell culture substrates can be used to generate in vitro cell culture environments similar to the in vivo cell niches. In vivo, the physical properties of the extracellular matrix (ECM), such as its topography, provide physical cues that play an important role in modulating cell function. Mimicking these properties remains a challenge to provide in vitro realistic environments for cells. Artificially generated substrates' topographies were used extensively to explore this important surface cue. More recently, the replication of natural surface topographies has been enabling to exploration of characteristics such as hierarchy and size scales relevant for cells as advanced biomimetic substrates. These substrates offer more realistic and mimetic environments regarding the topographies found in vivo. This review will highlight the use of natural surface topographies as a template to generate substrates for in-vitro cell culture. This review starts with an analysis of the main cell functions that can be regulated by the substrate's surface topography through cell-substrate interactions. Then, we will discuss research works wherein substrates for cell biology decorated with natural surface topographies were used and investigated regarding their influence on cellular performance. At the end of this review, we will highlight the advantages and challenges of the use of natural surface topographies as a template for the generation of advanced substrates for cell culture.

Biocompatible coatings based on photo-crosslinkable cellulose derivatives

Materials derived from renewable resources have great potential to replace fossil-based plastics in biomedical applications. In this study, the synthesis of cellulose-based photoresists by esterification with methacrylic acid anhydride and sorbic acid was investigated. These resists polymerize under UV irradiation in the range of λ = 254 nm to 365 nm, with or, in the case of the sorbic acid derivative, without using an additional photoinitiator. Usability for biomedical applications was demonstrated by investigating the adhesion and viability of a fibrosarcoma cell line (HT-1080). Compared to polystyrene, the material widely used for cell culture dishes, cell adhesion to the biomaterials tested was even stronger, as assessed by a centrifugation assay. Remarkably, chemical surface modifications of cellulose acetate with methacrylate and sorbic acid allow direct attachment of HT-1080 cells without adding protein modifiers or ligands. Furthermore, cells on both biomaterials show similar cell viability, not significantly different from polystyrene, indicating no significant impairment or enhancement, allowing the use of these cellulose derivatives as support structures for scaffolds or as a self-supporting coating for cell culture solely based on renewable resources.

Strontium-driven physiological to pathological transition of bone-like architecture: A dose-dependent investigation

Whilst strontium (Sr2+) is widely investigated for treating osteoporosis, it is also related to mineralization disorders such as rickets and osteomalacia. In order to clarify the physiological and pathological effects of Sr2+ on bone biomineralization , we performed a dose-dependent investigation in bone components using a 3D scaffold that displays the hallmark features of bone tissue in terms of composition (osteoblast, collagen, carbonated apatite) and architecture (mineralized collagen fibrils hierarchically assembled into a twisted plywood geometry). As the level of Sr2+ is increased from physiological-like to excess, both the mineral and the collagen fibrils assembly are destabilized, leading to a drop in the Young modulus, with strong implications on pre-osteoblastic cell proliferation. Furthermore, the microstructural and mechanical changes reported here correlate with that observed in bone-weakening disorders induced by Sr2+ accumulation, which may clarify the paradoxical effects of Sr2+ in bone mineralization. More generally, our results provide physicochemical insights into the possible effects of inorganic ions on the assembly of bone extracellular matrix and may contribute to the design of safer therapies for treating osteoporosis. STATEMENT OF SIGNIFICANCE: Physiological-like (10% Sr2+) and excess accumulation-like (50% Sr2+) doses of Sr2+ are investigated in 3D biomimetic assemblies possessing the high degree of organization found in the extracellular of bone. Above the physiological dose, the organic and inorganic components of the bone-like scaffold are destabilized, resulting in impaired cellular activity, which correlates with bone-weakening disorders induced by Sr2+.

Electrospun Poly(L-Lactic Acid)/Gelatin Hybrid Polymer as a Barrier to Periodontal Tissue Regeneration

Poly(L-lactic acid) (PLLA) and PLLA/gelatin polymers were prepared via electrospinning to evaluate the effect of PLLA and gelatin content on the mechanical properties, water uptake capacity (WUC), water contact angle (WCA), degradation rate, cytotoxicity and cell proliferation of membranes. As the PLLA concentration increased from 1 wt% to 3 wt%, the tensile strength increased from 5.8 MPa to 9.1 MPa but decreased to 7.0 MPa with 4 wt% PLLA doping. The WUC decreased rapidly from 594% to 236% as the PLLA content increased from 1 to 4 wt% due to the increased hydrophobicity of PLLA. As the gelatin content was increased to 3 wt% PLLA, the strength, WUC and WCA of the PLLA/gelatin membrane changed from 9.1 ± 0.9 MPa to 13.3 ± 2.3 MPa, from 329% to 1248% and from 127 ± 1.2° to 0°, respectively, with increasing gelatin content from 0 to 40 wt%. However, the failure strain decreased from 3.0 to 0.5. The biodegradability of the PLLA/gelatin blend increased from 3 to 38% as the gelatin content increased to 40 wt%. The viability of L-929 and MG-63 cells in the PLLA/gelatin blend was over 95%, and the excellent cell proliferation and mechanical properties suggested that the tunable PLLA/gelatin barrier membrane was well suited for absorbable periodontal tissue regeneration.

Biological Performance of Duplex PEO + CNT/PCL Coating on AZ31B Mg Alloy for Orthopedic and Dental Applications

To regulate the degradation rate and improve the surface biocompatibility of the AZ31B magnesium alloy, three different coating systems were produced via plasma electrolytic oxidation (PEO): simple PEO, PEO incorporating multi-walled carbon nanotubes (PEO + CNT), and a duplex coating that included a polycaprolactone top layer (PEO + CNT/PCL). Surfaces were characterized by chemical content, roughness, topography, and wettability. Biological properties analysis included cell metabolism and adhesion. PEO ± CNT resulted in an augmented surface roughness compared with the base material (BM), while PCL deposition produced the smoothest surface. All surfaces had a contact angle below 90°. The exposure of gFib-TERT and bmMSC to culture media collected after 3 or 24 h did not affect their metabolism. A decrease in metabolic activity of 9% and 14% for bmMSC and of 14% and 29% for gFib-TERT was observed after 3 and 7 days, respectively. All cells died after 7 days of exposure to BM and after 15 days of exposure to coated surfaces. Saos-2 and gFib-TERT adhered poorly to BM, in contrast to bmMSC. All cells on PEO anchored into the pores with filopodia, exhibited tiny adhesion protrusions on PEO + CNT, and presented a web-like spreading with lamellipodia on PEO + CNT/PCL. The smooth and homogenous surface of the duplex PEO + CNT/PCL coating decreased magnesium corrosion and led to better biological functionality.

The Use of Small-Molecule Compounds for Cell Adhesion and Migration in Regenerative Medicine

Cell adhesion is essential for cell survival, communication, and regulation, and it is of fundamental importance in the development and maintenance of tissues. Cell adhesion has been widely explored due to its many important roles in the fields of tissue regenerative engineering and cell biology. This is because the mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. Currently, biomaterials for regenerative medicine have been heavily investigated as substrates for promoting a cells' adhesive properties and subsequent proliferation, tissue differentiation, and maturation. Specifically, the manipulation of biomaterial surfaces using ECM coatings such as fibronectin extracted from animal-derived ECM have contributed significantly to tissue regenerative engineering as well as basic cell biology research. Additionally, synthetic and natural bioadhesive agents with pronounced abilities to enhance adhesion in numerous biological components and molecules have also been assessed in the field of tissue regeneration. Research into the use of facilitative bioadhesives has aimed to further optimize the biocompatibility, biodegradability, toxicity levels, and crosslinking duration of bioadhesive materials for improved targeted delivery and tissue repair. However, the restrictive drawbacks of some of these bioadhesive and animal-derived materials include the potential risk of disease transmission, immunogenicity, poor reproducibility, impurities, and instability. Therefore, it is necessary for alternative strategies to be sought out to improve the quality of cell adhesion to biomaterials. One promising strategy involves the use of cell-adhesive small molecules. Small molecules are relatively inexpensive, stable, and low-molecular-weight (<1000 Da) compounds with great potential to serve as efficient alternatives to conventional bioadhesives, ECM proteins, and other derived peptides. Over the past few years, a number of cell adhesive small molecules with the potential for tissue regeneration have been reported. In this review, we discuss the current progress using cell adhesive small molecules to regulate tissue regeneration.

The Impact of Biomaterial Surface Properties on Engineering Neural Tissue for Spinal Cord Regeneration

Tissue engineering for spinal cord injury (SCI) remains a complex and challenging task. Biomaterial scaffolds have been suggested as a potential solution for supporting cell survival and differentiation at the injury site. However, different biomaterials display multiple properties that significantly impact neural tissue at a cellular level. Here, we evaluated the behavior of different cell lines seeded on chitosan (CHI), poly (ε-caprolactone) (PCL), and poly (L-lactic acid) (PLLA) scaffolds. We demonstrated that the surface properties of a material play a crucial role in cell morphology and differentiation. While the direct contact of a polymer with the cells did not cause cytotoxicity or inhibit the spread of neural progenitor cells derived from neurospheres (NPCdn), neonatal rat spinal cord cells (SCC) and NPCdn only attached and matured on PCL and PLLA surfaces. Scanning electron microscopy and computational analysis suggested that cells attached to the material's surface emerged into distinct morphological populations. Flow cytometry revealed a higher differentiation of neural progenitor cells derived from human induced pluripotent stem cells (hiPSC-NPC) into glial cells on all biomaterials. Immunofluorescence assays demonstrated that PCL and PLLA guided neuronal differentiation and network development in SCC. Our data emphasize the importance of selecting appropriate biomaterials for tissue engineering in SCI treatment.

A method for harvesting viable cells from wound dressings

Wound fluid has been well studied for exploring protein biomarkers contained in it. However, cells in wound fluid have not received much attention due to the difficulty in their collection. Our study aimed to establish a method for collecting viable cells from discarded wound dressings. A protocol was designed to wash out nonadherent cells and detach adherent cells from silicone-faced foam wound dressings using trypsin-EDTA. The optimal concentration and incubation time of trypsin-EDTA for collecting equivalent proportions of different cell types to the original cell population were determined in vitro. Cell composition and gene expression changes in monocytes, lymphocytes, neutrophils, fibroblasts and keratinocytes were confirmed using immunocytochemistry and RNA-sequencing ex vivo. Full-thickness wounds were created on 9-week-old male C57BL/6J mice. Wound fluid was collected, and half of it was applied to the wound dressings. The original cell population in the wound fluid and the cell population collected from wound dressings were compared. In the in vitro study, 0.25% trypsin-EDTA and 2.5-min incubation time were considered optimal for collecting adherent cells from wound dressings. In the ex vivo study, among all cell types, only CD3+ lymphocytes showed a significantly higher cell proportion in the collected group. The relative gene expression of the five selected cells showed no significant changes (p-value >0.05, |log2 fold change| < 1.5, differential gene expression analysis). Viable nonadherent and adherent cells were collected from wound dressings without altering gene expression and could be used in future studies for cellular analysis of wound fluid.

S-Protected Thiolated Chitosan versus Thiolated Chitosan as Cell Adhesive Biomaterials for Tissue Engineering

Chitosan (Ch) and different Ch derivatives have been applied in tissue engineering (TE) because of their biocompatibility, favored mechanical properties, and cost-effectiveness. Most of them, however, lack cell adhesive properties that are crucial for TE. In this study, we aimed to design an S-protected thiolated Ch derivative exhibiting high cell adhesive properties serving as a scaffold for TE. 3-((2-Acetamido-3-methoxy-3-oxopropyl)dithio) propanoic acid was covalently attached to Ch via a carbodiimide-mediated reaction. Low-, medium-, and high-modified Chs (Ch-SS-1, Ch-SS-2, and Ch-SS-3) with 54, 107 and 140 μmol of ligand per gram of polymer, respectively, were tested. In parallel, three thiolated Chs, namely Ch-SH-1, Ch-SH-2, and Ch-SH-3, were prepared by conjugating N-acetyl cysteine to Ch at the same degree of modification to compare the effectiveness of disulfide versus thiol modification on cell adhesion. Ch-SS-1 showed better cell adhesion capability than Ch-SS-2 and Ch-SS-3. This can be explained by the more lipophilic surfaces of Ch-SS as a higher modification was made. Although Ch-SH-1, Ch-SH-2, and Ch-SH-3 were shown to be good substrates for cell adhesion, growth, and proliferation, Ch-SS polymers were superior to Ch-SH polymers in the formation of 3D cell cultures. Cryogels structured by Ch-SS-1 (SSg) resulted in homogeneous scaffolds with tunable pore size and mechanical properties by changing the mass ratio between Ch-SS-1 and heparin used as a cross-linker. SSg scaffolds possessing interconnected microporous structures showed good cell migration, adhesion, and proliferation. Therefore, Ch-SS can be used to construct tunable cryogel scaffolds that are suitable for 3D cell culture and TE.

Optimizing the fabrication of a 3D high-resolution implant for neural stimulation

BACKGROUND

Tissue-integrated micro-electronic devices for neural stimulation hold great potential in restoring the functionality of degenerated organs, specifically, retinal prostheses, which are aimed at vision restoration. The fabrication process of 3D polymer-metal devices with high resolution and a high aspect-ratio (AR) is very complex and faces many challenges that impair its functionality.

APPROACH

Here we describe the optimization of the fabrication process of a bio-functionalized 3D high-resolution 1mm circular subretinal implant composed of SU-8 polymer integrated with dense gold microelectrodes (23μm pitch) passivated with 3D micro-well-like structures (20μm diameter, 3μm resolution). The main challenges were overcome by step-by-step planning and optimization while utilizing a two-step bi-layer lift-off process; bio-functionalization was carried out by N2 plasma treatment and the addition of a bio-adhesion molecule.

MAIN RESULTS

In-vitro and in-vivo investigations, including SEM and FIB cross section examinations, revealed a good structural design, as well as a good long-term integration of the device in the rat sub-retinal space and cell migration into the wells. Moreover, the feasibility of subretinal neural stimulation using the fabricated device was demonstrated in-vitro by electrical activation of rat's retina.

CONCLUSIONS

The reported process and optimization steps described here in detail can aid in designing and fabricating retinal prosthetic devices or similar neural implants.

Highly reproducible and cost-effective one-pot organoid differentiation using a novel platform based on PF-127 triggered spheroid assembly

Organoid technology offers sophisticatedin vitrohuman models for basic research and drug development. However, low batch-to-batch reproducibility and high cost due to laborious procedures and materials prevent organoid culture standardization for automation and high-throughput applications. Here, using a novel platform based on the findings that Pluronic F-127 (PF-127) could trigger highly uniform spheroid assembly through a mechanism different from plate coating, we develop a one-pot organoid differentiation strategy. Using our strategy, we successfully generate cortical, nephron, hepatic, and lung organoids with improved reproducibility compared to previous methods while reducing the original costs by 80%-95%. In addition, we adapt our platform to microfluidic chips allowing automated culture. We showcase that our platform can be applied to tissue-specific screening, such as drug toxicity and transfection reagents testing. Finally, we generateNEAT1knockout tissue-specific organoids and showNEAT1modulates multiple signaling pathways fine-tuning the differentiation of nephron and hepatic organoids and suppresses immune responses in cortical organoids. In summary, our strategy provides a powerful platform for advancing organoid research and studying human development and diseases.

Polyvinylpyrrolidone-Alginate Film Barriers for Abdominal Surgery: Anti-Adhesion Effect in Murine Model

Surgical operations on the peritoneum are often associated with the formation of adhesions, which can interfere with the normal functioning of the internal organs. The effectiveness of existing barrier materials is relatively low. In this work, the effectiveness of soluble alginate-polyvinylpyrrolidone (PVP-Alg) and non-soluble Ca ion cross-linked (PVP-Alg-Ca) films in preventing these adhesions was evaluated. Experiments in vivo were performed on mice via mechanical injury to the adjacent peritoneum wall and the caecum, followed by the application of PVP-Alg or PVP-Alg-Ca films to the injured area. After 7 days, samples from the peritoneal wall and caecum were analyzed using histology and quantitative polymerase chain reaction (qPCR). It was shown that the expression of genes responsible for adhesion formation in the caecum in the PVP-Alg group was comparable to that in the control group, while in the PVP-Alg-Ca group, it increased by 5-10 times. These results were consistent with the histology: in the PVP-Alg group, the adhesions did not form, while in the PVP-Alg-Ca group, the adhesions corresponded to five points on the adhesion scale. Therefore, the formation of intraperitoneal adhesions can be effectively prevented by non-crosslinked, biodegradable PVP-Alg films, whereas cross-linked, not biodegradable PVP-Alg-Ca films cause inflammation and adhesion formation.

Development of Matrix Metalloproteinases-Mediated Extracellular Matrix Remodeling in Regenerative Medicine: A Mini Review

Extracellular matrix (ECM) components confer biomechanical properties, maintain cell phenotype and mediate tissue homeostasis. ECM remodeling is complex and plays a key role in both physiological and pathological processes. Matrix metalloproteinases (MMPs) are a group of enzymes responsible for ECM degradation and have been accepted as a key regulator in ECM remodeling. In this mini-review, we summarize MMPs categories, functions and the targeted substrates. We then discuss current understanding of the role of MMPs-mediated events, including inflammation reaction, angiogenesis, cellular activities, etc., in ECM remodeling in the context of regenerative medicine.

Novel Hydrophilic Oligomer-Crosslinked Gelatin-Based Hydrogels for Biomedical Applications

Gelatin-based hydrogels have shown good injectability and biocompatibility and have been broadly used for drug delivery and tissue regeneration. However, their low mechanical strengths and fast degradation rates must be modified for long-term implantation applications. With an aim to develop mechanically stable hydrogels, reactive anhydride-based oligomers were developed and used to fabricate gelatin-based crosslinked hydrogels in this study. A cascade of hydrophilic oligomers containing reactive anhydride groups was synthesized by free radical polymerization. These oligomers varied in degree of reactivity, comonomer composition, and showed low molecular weights (M_n < 5 kDa). The reactive oligomers were utilized to fabricate hydrogels that differed in their mechanical strengths and degradation profiles. These formulations exhibited good cytocompatibility with human adipose tissue-derived stem cells (hADCs). In conclusion, the reactive MA-containing oligomers were successfully synthesized and utilized for the development of oligomer-crosslinked hydrogels. Such oligomer-crosslinked gelatin-based hydrogels hold promise as drug or cell carriers in various biomedical applications.

Surface modifications of biomaterials in different applied fields

Biomaterial implantation into the human body plays a key role in the medical field and biological applications. Increasing the life expectancy of biomaterial implants, reducing the rejection reaction inside the human body and reducing the risk of infection are the problems in this field that need to be solved urgently. The surface modification of biomaterials can change the original physical, chemical and biological properties and improve the function of materials. This review focuses on the application of surface modification techniques in various fields of biomaterials reported in the past few years. The surface modification techniques include film and coating synthesis, covalent grafting, self-assembled monolayers (SAMs), plasma surface modification and other strategies. First, a brief introduction to these surface modification techniques for biomaterials is given. Subsequently, the review focuses on how these techniques change the properties of biomaterials, and evaluates the effects of modification on the cytocompatibility, antibacterial, antifouling and surface hydrophobic properties of biomaterials. In addition, the implications for the design of biomaterials with different functions are discussed. Finally, based on this review, it is expected that the biomaterials have development prospects in the medical field.

Integrated bioinformatics and wet-lab analysis revealed cell adhesion prominent genes CDC42, TAGLN and GSN as prognostic biomarkers in colonic-polyp lesions

Colorectal cancers are derived from intestinal polyps. Normally, alterations in cell adhesion genes expression cause deviation from the normal cell cycle, leading to cancer development, progression, and invasion. The present study aimed to investigate the elusive expression pattern of CDC42, TAGLN, and GSN genes in patients with high and low-risk polyp samples, and also colorectal cancer patients and their adjacent normal tissues. In upcoming study, 40 biopsy samples from Taleghani Hospital (Tehran, Iran) were collected, consisting of 20 colon polyps and 20 paired adjacent normal tissues. The expression of the nominated genes CDC42, TAGLN, and GSN was analyzed using quantitative polymerase chain reaction (Q-PCR) and relative quantification was determined using the 2^-ΔΔCt method. ROC curve analysis was performed to compare high-risk and low-risk polyps for the investigated genes. The expression of adhesion molecule genes was also evaluated using TCGA data and the correlation between adhesion molecule gene expression and immunophenotype was analyzed. The role of mi-RNAs and lncRNAs in overexpression of adhesion molecule genes was studied. Lastly, GO and KEGG were performed to identify pathways related to adhesion molecule genes expression in healthy, normal adjacent, and COAD tissues. The results showed that the expression patterns of these genes were significantly elevated in high-risk adenomas compared to low-risk polyps and normal tissues and were associated with various clinicopathological characteristics. The estimated AUC for CDC42, TAGLN, and GSN were 0.87, 0.77, and 0.80, respectively. The study also analyzed COAD cancer patient data and found that the selected gene expression in cancer patients was significantly reduced compared to high-risk polyps and healthy tissues. Survival analysis showed that while the expression level of the GSN gene had no significant relationship with survival rate, the expression of CDC42 and TAGLN genes did have a meaningful relationship, but with opposite effects, suggesting the potential use of these genes as diagnostic or prognostic markers for colorectal cancer. The present study's findings suggest that the expression pattern of CDC42, TAGLN, and GSN genes was significantly increased during the transformation of normal tissue to polyp lesions, indicating their potential as prognostic biomarkers for colorectal polyp development. Further results provide valuable insights into the potential use of these genes as diagnostic or prognostic markers for colorectal cancer. However, further studies are necessary to validate these findings in larger cohorts and to explore the underlying mechanisms of these genes in the development and progression of colorectal cancer.

Droplet microarray platforms for high-throughput drug screening

High-throughput screening platforms are fundamental for the rapid and efficient processing of large amounts of experimental data. Parallelization and miniaturization of experiments are important for improving their cost-effectiveness. The development of miniaturized high-throughput screening platforms is essential in the fields of biotechnology, medicine, and pharmacology. Currently, most laboratories use 96- or 384-well microtiter plates for screening; however, they have disadvantages, such as high reagent and cell consumption, low throughput, and inability to avoid cross-contamination, which need to be further optimized. Droplet microarrays, as novel screening platforms, can effectively avoid these shortcomings. Here, the preparation method of the droplet microarray, method of adding compounds in parallel, and means to read the results are briefly described. Next, the latest research on droplet microarray platforms in biomedicine is presented, including their application in high-throughput culture, cell screening, high-throughput nucleic acid screening, drug development, and individualized medicine. Finally, the challenges and future trends in droplet microarray technology are summarized.

Application of single cell force spectroscopy (SCFS) to the assessment of cell adhesion to peptide-decorated surfaces

The adhesion forces of cells to peptide-coated functionalized materials were assessed through the Single Cell Force Spectroscopy (SCFS) technique in order to develop a methodology that allows the fast selection of peptide motifs that favor the interaction between cells and the biomaterial. Borosilicate glasses were functionalized using the activated vapor silanization process (AVS) and subsequently decorated with an RGD- containing peptide using the EDC/NHS crosslinking chemistry. It is shown that the RGD-coated glass induces larger attachment forces on mesenchymal stem cell cultures (MSCs), compared to the bare glass substrates. These higher forces correlate well with the enhanced adhesion of the MSCs observed on RGD-coated substrates through conventional adhesion cell cultures and inverse centrifugation tests. The methodology based on the SCFS technique presented in this work constitutes a fast procedure for the screening of new peptides or their combinations to select candidates that may enhance the response of the organism to the implant of the functionalized biomaterials.

Evaluation of Low-dose Radiation-induced DNA Damage and Repair in 3D Printed Human Cellular Constructs

ABSTRACT

DNA double-strand breaks (DSBs) induced by ionizing radiation (IR) are considered to be the most critical lesion that when unrepaired or misrepaired leads to genomic instability or cell death depending on the radiation exposure dose. The potential health risks associated with exposures of low-dose radiation are of concern since they are being increasingly used in diverse medical and non-medical applications. Here, we have used a novel human tissue-like 3-dimensional bioprint to evaluate low-dose radiation-induced DNA damage response. For the generation of 3-dimensional tissue-like constructs, human hTERT immortalized foreskin fibroblast BJ1 cells were extrusion printed and further enzymatically gelled in a gellan microgel-based support bath. Low-dose radiation-induced DSBs and repair were analyzed in the tissue-like bioprints by indirect immunofluorescence using a well-known DSB surrogate marker, 53BP1, at different post-irradiation times (0.5 h, 6 h, and 24 h) after treatment with various doses of γ rays (50 mGy, 100 mGy, and 200 mGy). The 53BP1 foci showed a dose dependent induction in the tissue bioprints after 30 min of radiation exposure and subsequently declined at 6 h and 24 h in a dose-dependent manner. The residual 53BP1 foci number observed at 24 h post-irradiation time for the γ-ray doses of 50 mGy, 100 mGy, and 200 mGy was not statistically different from mock treated bioprints illustrative of an efficient DNA repair response at these low-dose exposures. Similar results were obtained for yet another DSB surrogate marker, γ-H2AX (phosphorylated form of histone H2A variant) in the human tissue-like constructs. Although we have primarily used foreskin fibroblasts, our bioprinting approach-mimicking a human tissue-like microenvironment-can be extended to different organ-specific cell types for evaluating the radio-response at low-dose and dose-rates of IR.

Monitoring Cell Adhesion on Polycaprolactone-Chitosan Films with Varying Blend Ratios by Quartz Crystal Microbalance with Dissipation

A detailed understanding of the cell adhesion on polymeric surfaces is required to improve the performance of biomaterials. Quartz crystal microbalance with dissipation (QCM-D) as a surface-sensitive technique has the advantage of label-free and real-time monitoring of the cell-polymer interface, providing distinct signal patterns for cell-polymer interactions. In this study, QCM-D was used to monitor human fetal osteoblastic (hFOB) cell adhesion onto polycaprolactone (PCL) and chitosan (CH) homopolymer films as well as their blend films (75:25 and 25:75). Complementary cell culture assays were performed to verify the findings of QCM-D. The thin polymer films were successfully prepared by spin-coating, and relevant properties, i.e., surface morphology, ζ-potential, wettability, film swelling, and fibrinogen adsorption, were characterized. The adsorbed amount of fibrinogen decreased with an increasing percentage of chitosan in the films, which predominantly showed an inverse correlation with surface hydrophilicity. Similarly, the initial cell sedimentation after 1 h resulted in lesser cell deposition as the chitosan ratio increased in the film. Furthermore, the QCM-D signal patterns, which were measured on the homopolymer and blend films during the first 18 h of cell adhesion, also showed an influence of the different interfacial properties. Cells fully spread on pure PCL films and had elongated morphologies as monitored by fluorescence microscopy and scanning electron microscopy (SEM). Corresponding QCM-D signals showed the highest frequency drop and the highest dissipation. Blend films supported cell adhesion but with lower dissipation values than for the PCL film. This could be the result of a higher rigidity of the cell-blend interface because the cells do not pass to the next stages of spreading after secretion of their extracellular matrix (ECM) proteins. Variations in the QCM-D data, which were obtained at the blend films, could be attributed to differences in the morphology of the films. Pure chitosan films showed limited cell adhesion accompanied by low frequency drop and low dissipation.

Bladder Cancer Cells Interaction with Lectin-Coated Surfaces under Static and Flow Conditions

Aberrant expression of glycans, i.e., oligosaccharide moiety covalently attached to proteins or lipids, is characteristic of various cancers, including urothelial ones. The binding of lectins to glycans is classified as molecular recognition, which makes lectins a strong tool for understanding their role in developing diseases. Here, we present a quantitative approach to tracing glycan-lectin interactions in cells, from the initial to the steady phase of adhesion. The cell adhesion was measured between urothelial cell lines (non-malignant HCV29 and carcinoma HT1376 and T24 cells) and lectin-coated surfaces. Depending on the timescale, single-cell force spectroscopy, and adhesion assays conducted in static and flow conditions were applied. The obtained results reveal that the adhesion of urothelial cells to two specific lectins, i.e., phytohemagglutinin-L and wheat germ agglutinin, was specific and selective. Thus, these lectins can be applied to selectively capture, identify, and differentiate between cancer types in a label-free manner. These results open up the possibility of designing lectin-based biosensors for diagnostic or prognostic purposes and developing strategies for drug delivery that could target cancer-associated glycans.

Label-free and dynamic monitoring of cell evolutions using wavelength-multiplexing surface plasmon resonance holographic microscopy

Dynamic characterizations of intracellular variations and cell-substrate interactions under different external environments are critical to study cell behaviors and exploring biological applications. However, techniques that are capable of dynamically and simultaneously measuring multiple parameters of living cells in a wide-field manner have rarely been reported. Here, we present a wavelength-multiplexing surface plasmon resonance holographic microscopy which allows wide-field, simultaneous, and dynamic measurements of cell parameters, including cell-substrate distance and cytoplasm refractive index (RI). We use two lasers of 632.8 nm and 690 nm as light sources. Two beam splitters are employed in the optical setup to separately adjust the incident angle of two light beams. Then, surface plasmon resonance (SPR) can be excited for each wavelength under SPR angles. We demonstrate the advances of the proposed apparatus by systematically studying the cell responses to osmotic pressure stimuli from the environmental medium at the cell-substrate interface. The SPR phase distributions of the cell are firstly mapped at two wavelengths, then the cell-substrate distance and cytoplasm RI are retrieved using a demodulation method. Based on phase response differences between two wavelengths and monotonic changes of SPR phase with cell parameters, cell-substrate distance, and cytoplasm RI can be determined simultaneously using an inverse algorithm. This work affords a new optical measurement technique to dynamically characterize cell evolutions and investigate cell properties in various cellular activities. It may become a useful tool in the bio-medical and bio-monitoring areas.

Investigation of the effects of porosity and volume fraction on the atomic behavior of cancer cells and microvascular cells of 3DN5 and 5OTF macromolecular structures during hematogenous metastasis using the molecular dynamics method

BACKGROUND AND OBJECTIVE

The molecular dynamics (MD) simulation is a powerful tool for researching how cancer patients are treated. The efficiency of many factors may be predicted using this approach in great detail and with atomic accuracy.

METHODS

The MD simulation method was used to investigate the impact of porosity and the number of cancer cells on the atomic behavior of cancer cells during the hematogenous spread. In order to examine the stability of simulated structures, temperature and potential energy (PE) values are used. To evaluate how cell structure has changed, physical parameters such as gyration radius, interaction force, and interaction energy are also used.

RESULTS

The findings demonstrate that the samples' gyration radius, interaction energy, and interaction force rose from 41.33 Å, -551.38 kcal/mol, and -207.10 kcal/mol Å to 49.49, -535.94 kcal/mol, and -190.05 kcal/mol Å, respectively, when the porosity grew from 0% to 5%. Also, the interaction energy and force in the samples fell from -551.38 kcal/mol and -207.10 kcal/mol to -588.03 kcal/mol and -237.81 kcal/mol Å, and the amount of gyration radius reduced from 41.33 to 37.14 Å as the number of cancer cells rose from 1 to 5 molecules. The strength and stability of the simulated samples will improve when the radius of gyration is decreased.

CONCLUSIONS

Therefore, high accumulation of cancer cells will make them resistant to atomic collapse. It is expected that the results of this simulation should be used to optimize cancer treatment processes further.

GRB10 is a novel factor associated with gastric cancer proliferation and prognosis

GRB10 and its family members GRB7 and GRB14 were important adaptor proteins. They regulated many cellular functions by interacting with various tyrosine kinase receptors and other phosphorus-containing amino acid proteins. More and more studies have shown that the abnormal expression of GRB10 is closely related to the occurrence and development of cancer. In our current research, expression data for 33 cancers from the TCGA database was downloaded for analysis. It was found that GRB10 was up-regulated in cholangiocarcinoma, colon adenocarcinoma, head and neck squamous carcinoma, renal chromophobe, clear renal carcinoma, hepatocellular carcinoma, lung adenocarcinoma, lung squamous carcinoma, gastric adenocarcinoma and thyroid carcinoma. Especially in gastric cancer, the high GRB10 expression was closely associated with poorer overall survival. Further research showed that the knockdown of GRB10 inhibited proliferation and migration ability in gastric cancer. Also, there was a potential binding site for miR-379-5p on the 3'UTR of GRB10. Overexpression of miR-379-5p in gastric cancer cells reduced GRB10-regulated gastric cancer proliferation and migration capacity. In addition, we found that tumor growth was slower in a mice xenograft model with knock down of GRB10 expression. These findings suggested that miR-379-5p suppresses gastric cancer development by downregulating GRB10 expression. Therefore, miR-379-5p and GRB10 were expected to be potential targets for the treatment of gastric cancer.

Investigation of the In Vitro and In Vivo Biocompatibility of a Three-Dimensional Printed Thermoplastic Polyurethane/Polylactic Acid Blend for the Development of Tracheal Scaffolds

Tissue-engineered polymeric implants are preferable because they do not cause a significant inflammatory reaction in the surrounding tissue. Three-dimensional (3D) technology can be used to fabricate a customised scaffold, which is critical for implantation. This study aimed to investigate the biocompatibility of a mixture of thermoplastic polyurethane (TPU) and polylactic acid (PLA) and the effects of their extract in cell cultures and in animal models as potential tracheal replacement materials. The morphology of the 3D-printed scaffolds was investigated using scanning electron microscopy (SEM), while the degradability, pH, and effects of the 3D-printed TPU/PLA scaffolds and their extracts were investigated in cell culture studies. In addition, subcutaneous implantation of 3D-printed scaffold was performed to evaluate the biocompatibility of the scaffold in a rat model at different time points. A histopathological examination was performed to investigate the local inflammatory response and angiogenesis. The in vitro results showed that the composite and its extract were not toxic. Similarly, the pH of the extracts did not inhibit cell proliferation and migration. The analysis of biocompatibility of the scaffolds from the in vivo results suggests that porous TPU/PLA scaffolds may facilitate cell adhesion, migration, and proliferation and promote angiogenesis in host cells. The current results suggest that with 3D printing technology, TPU and PLA could be used as materials to construct scaffolds with suitable properties and provide a solution to the challenges of tracheal transplantation.

Investigation of Three-Dimensional Bacterial Adhesion Manner on Model Organic Surfaces Using Quartz Crystal Microbalance with Energy Dissipation Monitoring

Bacterial biofilms reduce the performance and efficiency of biomedical and industrial devices. The initial step in forming bacterial biofilms is the weak and reversible attachment of the bacterial cells onto the surface. This is followed by bond maturation and secretion of polymeric substances, which initiate irreversible biofilm formation, resulting in stable biofilms. This implies that understanding the initial reversible stage of the adhesion process is crucial to prevent bacterial biofilm formation. In this study, we analyzed the adhesion processes of E. coli on self-assembled monolayers (SAMs) with different terminal groups using optical microscopy and quartz crystal microbalance with energy dissipation (QCM-D) monitoring. We found that a considerable number of bacterial cells adhere to hydrophobic (methyl-terminated) and hydrophilic protein-adsorbing (amine- and carboxy-terminated) SAMs forming dense bacterial adlayers while attaching weakly to hydrophilic protein-resisting SAMs [oligo(ethylene glycol) (OEG) and sulfobetaine (SB)], forming sparse but dissipative bacterial adlayers. Moreover, we observed positive shifts in the resonant frequency for the hydrophilic protein-resisting SAMs at high overtone numbers, suggesting how bacterial cells cling to the surface using their appendages as explained by the coupled-resonator model. By exploiting the differences in the acoustic wave penetration depths at each overtone, we estimated the distance of the bacterial cell body from different surfaces. The estimated distances provide a possible explanation for why bacterial cells tend to attach firmly to some surfaces and weakly to others. This result is correlated to the strength of the bacterium-substratum bonds at the interface. Elucidating how the bacterial cells adhere to different surface chemistries can be a suitable guide in identifying surfaces with a more significant probability of contamination by bacterial biofilms and designing bacteria-resistant surfaces and coatings with excellent bacterial antifouling characteristics.

Physicochemical Principles of Adhesion Mechanisms in the Brain

The brain functions through neuronal circuits and networks that are synaptically connected. This type of connection can exist due to physical forces that interact to stabilize local contacts in the brain. Adhesion is a fundamental physical phenomenon that allows different layers, phases, and tissues to connect. Similarly, synaptic connections are stabilized by specialized adhesion proteins. This review discusses the basic physical and chemical properties of adhesion. Cell adhesion molecules (CAMs) such as cadherins, integrins, selectins, and immunoglobulin family of cell adhesion molecules (IgSF) will be discussed, and their role in physiological and pathological brain function. Finally, the role of CAMs at the synapse will be described. In addition, methods for studying adhesion in the brain will be presented.

Optimized genetic code expansion technology for time-dependent induction of adhesion GPCR-ligand engagement

The introduction of an engineered aminoacyl-tRNA synthetase/tRNA pair enables site-specific incorporation of unnatural amino acids (uAAs) with functionalized side chains into proteins of interest. Genetic Code Expansion (GCE) via amber codon suppression confers functionalities to proteins but can also be used to temporally control the incorporation of genetically encoded elements into proteins. Here, we report an optimized GCE system (GCEXpress) for efficient and fast uAA incorporation. We demonstrate that GCEXpress can be used to efficiently alter the subcellular localization of proteins within living cells. We show that click labeling can resolve co-labeling problems of intercellular adhesive protein complexes. We apply this strategy to study the adhesion G protein-coupled receptor (aGPCR) ADGRE5/CD97 and its ligand CD55/DAF that play central roles in immune functions and oncological processes. Furthermore, we use GCEXpress to analyze the time course of ADGRE5-CD55 ligation and replenishment of mature receptor-ligand complexes. Supported by fluorescence recovery after photobleaching (FRAP) experiments our results show that ADGRE5 and CD55 form stable intercellular contacts that may support transmission of mechanical forces onto ADGRE5 in a ligand-dependent manner. We conclude that GCE in combination with biophysical measurements can be a useful approach to analyze the adhesive, mechanical and signaling properties of aGPCRs and their ligand interactions. This article is protected by copyright. All rights reserved.

Involvement of redox signalling in tumour cell dormancy and metastasis

Decades of research on oncogene-driven carcinogenesis and gene-expression regulatory networks only started to unveil the complexity of tumour cellular and molecular biology. This knowledge has been successfully implemented in the clinical practice to treat primary tumours. In contrast, much less progress has been made in the development of new therapies against metastasis, which are the main cause of cancer-related deaths. More recently, the role of epigenetic and microenviromental factors has been shown to play a key role in tumour progression. Free radicals are known to communicate the intracellular and extracellular compartments, acting as second messengers and exerting a decisive modulatory effect on tumour cell signalling. Depending on the cellular and molecular context, as well as the intracellular concentration of free radicals and the activation status of the antioxidant system of the cell, the signalling equilibrium can be tilted either towards tumour cell survival and progression or cell death. In this regard, recent advances in tumour cell biology and metastasis indicate that redox signalling is at the base of many cell-intrinsic and microenvironmental mechanisms that control disseminated tumour cell fate and metastasis. In this manuscript, we will review the current knowledge about redox signalling along the different phases of the metastatic cascade, including tumour cell dormancy, making emphasis on metabolism and the establishment of supportive microenvironmental connections, from a redox perspective.

Recent Advances in Cell Sheet Engineering: From Fabrication to Clinical Translation

Cell sheet engineering, a scaffold-free tissue fabrication technique, has proven to be an important breakthrough technology in regenerative medicine. Over the past two decades, the field has developed rapidly in terms of investigating fabrication techniques and multipurpose applications in regenerative medicine and biological research. This review highlights the most important achievements in cell sheet engineering to date. We first discuss cell sheet harvesting systems, which have been introduced in temperature-responsive surfaces and other systems to overcome the limitations of conventional cell harvesting methods. In addition, we describe several techniques of cell sheet transfer for preclinical (in vitro and in vivo) and clinical trials. This review also covers cell sheet cryopreservation, which allows short- and long-term storage of cells. Subsequently, we discuss the cell sheet properties of angiogenic cytokines and vasculogenesis. Finally, we discuss updates to various applications, from biological research to clinical translation. We believe that the present review, which shows and compares fundamental technologies and recent advances in cell engineering, can potentially be helpful for new and experienced researchers to promote the further development of tissue engineering in different applications.

Polymeric Materials, Advances and Applications in Tissue Engineering: A Review

Tissue Engineering (TE) is an interdisciplinary field that encompasses materials science in combination with biological and engineering sciences. In recent years, an increase in the demand for therapeutic strategies for improving quality of life has necessitated innovative approaches to designing intelligent biomaterials aimed at the regeneration of tissues and organs. Polymeric porous scaffolds play a critical role in TE strategies for providing a favorable environment for tissue restoration and establishing the interaction of the biomaterial with cells and inducing substances. This article reviewed the various polymeric scaffold materials and their production techniques, as well as the basic elements and principles of TE. Several interesting strategies in eight main TE application areas of epithelial, bone, uterine, vascular, nerve, cartilaginous, cardiac, and urinary tissue were included with the aim of learning about current approaches in TE. Different polymer-based medical devices approved for use in clinical trials and a wide variety of polymeric biomaterials are currently available as commercial products. However, there still are obstacles that limit the clinical translation of TE implants for use wide in humans, and much research work is still needed in the field of regenerative medicine.

Curvature-dependent adhesion of vesicles

The morphology and motion behavior of a cell are highly influenced by its external biological, chemical, and physical stimuli, and geometric confinement. In this paper, it is revealed that the mean curvature of the substrate significantly influences the adhesion of vesicles. By employing the variational method and investigating the Helfrich free energy, the configuration of axisymmetric vesicles adhered to curved spherical substrates is obtained theoretically. Moreover, numerical simulations based on the finite element method are also carried out to investigate the adhesion of vesicles on curved substrates with complex shapes. It is found that for a fixed area of a vesicle, its total free energy depends mainly on the mean curvature of the adhesion region but is insensitive to the specific shape of the substrate, and the total free energy monotonically decreases with the increase in the mean curvature. In addition, possible biological significances of the curvature-dependent adhesion, such as the shape of the cell and antibiofouling, are discussed. This study may deepen our understanding of the underlying mechanisms of adhesion in cellular activities.

Bone Laser Patterning to Decipher Cell Organization

The laser patterning of implant materials for bone tissue engineering purposes has proven to be a promising technique for controlling cell properties such as adhesion or differentiation, resulting in enhanced osteointegration. However, the possibility of patterning the bone tissue side interface to generate microstructure effects has never been investigated. In the present study, three different laser-generated patterns were machined on the bone surface with the aim of identifying the best surface morphology compatible with osteogenic-related cell recolonization. The laser-patterned bone tissue was characterized by scanning electron microscopy and confocal microscopy in order to obtain a comprehensive picture of the bone surface morphology. The cortical bone patterning impact on cell compatibility and cytoskeleton rearrangement on the patterned surfaces was assessed using Stromal Cells from the Apical Papilla (SCAPs). The results indicated that laser machining had no detrimental effect on consecutively seeded cell metabolism. Orientation assays revealed that patterns with larger hatch distances were correlated with higher cell cytoskeletal conformation to the laser-machined patterns. To the best of our knowledge, this study is the first to consider and evaluate bone as a biological interface that can be engineered for improvement. Further investigations should focus on the in vivo implications of this direct patterning.

Sub-zero microRNA expression in the liver of the frozen hatchling painted turtle, Chrysemys picta marginata

The Midland painted turtle (Chrysemys picta marginata) are the highest known vertebrate species to experience and survive freezing and sub-zero temperatures. Painted turtles typically hatch from their eggs in the fall and remain underground in their nests until the following spring. While in these nests over the winter, hatchling turtles withstand over 50 % of their total extracellular body water freezing. Herein, the expression of microRNAs (miRNAs) was investigated in response to freezing stress in the hatchling painted turtle liver. A total of 204 known miRNAs were identified to be expressed in turtles, with 17 being upregulated and 13 being downregulated during freezing. KEGG and GO analyses suggested that upregulated miRNAs inhibit genes of cell cycle and Focal adhesion and Adherens junction, suggesting their role in downregulation of central metabolic processes necessary for metabolic rate depression (MRD) and maintaining the tissue homeostasis. Only 9 of the 36 enriched KEGG pathways were less targeted by miRNAs during freezing, including linoleic acid metabolism and multiple signaling pathways. These predicted upregulated pathways likely promote homeoviscous adaptation and expression of pro-survival/protective proteins for metabolic adaptations necessary for defence of liver during MRD. Overall, miRNA-seq analysis of liver revealed a strong role of miRNA in the adaptive strategy that not only enables hatchlings to substantially suppress their nonessential energy needs but also makes them flexible enough to restore and protect their basal organ functions by activating pro-survival processes.

Highly Adhesive Amyloid-Polyphenol Hydrogels for Cell Scaffolding

Rationally designing microstructures of soft hydrogels for specific biological functionalization is a challenge in tissue engineering applications. A novel and affordable soft hydrogel scaffold is constructed here by incorporating polyphenol modules with lysozyme amyloid fibrils (Lys AFs) via non-covalent self-assembly. Embedded polyphenols not only trigger hydrogel formation but also determine gel behavior by regulating the polyphenol gallol density and complex ratio. The feasibility of using a polyphenol-Lys AF hydrogel as a biocompatible cell scaffold, which is conducive to cell proliferation and spreading, is also shown. Notably, introducing polyphenols imparts the corresponding hydrogels a superior cell bioadhesive efficiency without further biofunctional decoration and thus may be successfully employed in both healthy and cancer cell lines. Confocal laser scanning microscopy also reveals that the highly expressed integrin-mediated focal adhesions form due to stimulation of the polyphenol-AF composite hydrogel, direct cell adhesion, proliferation, and spreading. Overall, this work constitutes a significant step forward in creating highly adhesive tissue culture platforms for in vitro culture of different cell types and may greatly expand prospects for future biomaterial design and development.

Acoustic Force-Based Cell-Matrix Avidity Measurement in High Throughput

Cancer cells interacting with the extracellular matrix (ECM) in the tumor microenvironment is pivotal for tumorigenesis, invasion, and metastasis. Cell-ECM adhesion has been intensively studied in cancer biology in the past decades to understand the molecular mechanisms underlying the adhesion events and extracellular mechanosensing, as well as develop therapeutic strategies targeting the cell adhesion molecules. Many methods have been established to measure the cell-ECM adhesion strength and correlate it with the metastatic potential of certain cancer types. However, those approaches are either low throughput, not quantitative, or with poor sensitivity and reproducibility. Herein, we developed a novel acoustic force spectroscopy based method to quantify the cell-ECM adhesion strength during adhesion maturation process using the emerging z-Movi^® technology. This can be served as a fast, simple, and high-throughput platform for functional assessment of cell adhesion molecules in a highly predictive and reproducible manner.

Cellasys #8: A Microphysiometric Assay for Real-Time Cell Analysis Within 24 Hours

Traditional biochemical assays present a vital toolbox to identify the effects of a test substance on cells. However, current assays are single-point measurements, only reveal one parameter at a time, and introduce potential interferences with labels and fluorescent lights. We have addressed these limitations by introducing the cellasys #8 test which is a microphysiometric assay for real-time cell analysis. Within 24 h, the cellasys #8 test is able to identify not only the effect of a test substance but also measure recovery effects. Due to the multi-parametric read-out, the test provides insights into metabolic as well as morphological changes in real-time. The following protocol provides a detailed introduction to the materials as well as a step-by-step description to support scientists with protocol adoption. The automated and standardized assay opens up manifold new application areas for scientists to study biological mechanisms, develop new therapeutic approaches, and validate serum-free media formulation.

Fluidic Force Microscopy and Atomic Force Microscopy Unveil New Insights into the Interactions of Preosteoblasts with 3D-Printed Submicron Patterns

Physical patterns represent potential surface cues for promoting osteogenic differentiation of stem cells and improving osseointegration of orthopedic implants. Understanding the early cell-surface interactions and their effects on late cellular functions is essential for a rational design of such topographies, yet still elusive. In this work, fluidic force microscopy (FluidFM) and atomic force microscopy (AFM) combined with optical and electron microscopy are used to quantitatively investigate the interaction of preosteoblasts with 3D-printed patterns after 4 and 24 h of culture. The patterns consist of pillars with the same diameter (200 nm) and interspace (700 nm) but distinct heights (500 and 1000 nm) and osteogenic properties. FluidFM reveals a higher cell adhesion strength after 24 h of culture on the taller pillars (32 ± 7 kPa versus 21.5 ± 12.5 kPa). This is associated with attachment of cells partly on the sidewalls of these pillars, thus requiring larger normal forces for detachment. Furthermore, the higher resistance to shear forces observed for these cells indicates an enhanced anchorage and can be related to the persistence and stability of lamellipodia. The study explains the differential cell adhesion behavior induced by different pillar heights, enabling advancements in the rational design of osteogenic patterns.

The association of cell adhesion molecules and selectins (VCAM-1, ICAM-1, E-selectin, L-selectin, and P-selectin) with microvascular complications in patients with type 2 diabetes: A follow-up study

OBJECTIVE

Chronic hyperglycemia induces pathogenic changes in the vascular endothelium and leads to the development of microvascular complications in patients with type 2 diabetes mellitus. Early identification of markers of diabetes complications may help to minimize the risk of the development and progression of microvascular complications.

METHODS

This follow-up study was conducted in type 2 diabetic cohort aged between 30-70 years. Out of 160 eligible participants, 70 of them completed follow-up. Levels of cell adhesion molecules and selectins (VCAM-1, ICAM-1, E-selectin, L-selectin and P-selectin) at baseline and follow-up were measured using Randox Evidence biochip analyzer (UK). Development of microvascular complications (diabetic neuropathy, retinopathy and nephropathy) was evaluated.

RESULTS

During the follow-up (2 years, median), 31 (44.3%) developed diabetic neuropathy, 10 (14.3%) developed diabetic retinopathy and, 27 (38.6%) developed diabetic nephropathy. A significant difference in levels of cell adhesion molecules and selectins were found in type 2 diabetic patients with and without microvascular complications. Multiple logistic regression analysis reveals that baseline level of VCAM-1 is significantly associated with microvascular complications; diabetic neuropathy(p=0.028), retinopathy (p=0.007) and nephropathy(p=<0.001). Additionally, levels of P-selectin (p=0.05) and L-selectin (p=0.008) is associated with diabetic nephropathy while retinopathy associated with L-selectin (p=0.005) only.

CONCLUSION

Cell adhesion molecules and selectins are indicators of microvascular complication among patients with type 2 diabetes (T2D). Association of these markers with the development of microvascular complications may provide additive information for developing strategies for diabetes management and prediction of microvascular complications.