Cell behaviour on polymer surfaces with different functional groups

Manufacturing Radially Aligned PCL Nanofibers Reinforced With Sulfated Levan and Evaluation of its Biological Activity for Healing Tympanic Membrane Perforations

The main objective of this study is to construct radially aligned PCL nanofibers reinforced with levan polymer and investigate their in vitro biological activities thoroughly. First Halomonas levan (HL) polysaccharide is hydrolyzed (hHL) and subjected to sulfation to attain Sulfated hydrolyzed Halomonas levan (ShHL)-based material indicating heparin mimetic properties. Then, optimization studies are carried out to produce coaxially generated radially aligned Poly(caprolactone) (PCL) -ShHL nanofibers via electrospinning. The obtained nanofibers are characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray (FESEM-EDX) analysis, and mechanical, contact angle measurement, biodegradability, and swelling tests as well. Afterward, cytotoxicity of artificial tympanic membranes is analyzed by MTT (3-(4,5-Dimethylthiazol-2-yl) -2,5 Diphenyltetrazolium Bromide) test, and their impacts on cell proliferation, cellular adhesion, wound healing processes are explored. Furthermore, an additional FESEM imaging is performed to manifest the interactions between fibroblasts and nanofibers. According to analytical measurements it is detected that PCL-ShHL nanofibers i) are smaller in fiber diameter, ii) are more biodegradable, iii) are more hydrophilic, and iv) demonstrated superior mechanical properties compared to PCL nanofibers. Moreover, it is also deciphered that PCL-ShHL nanofibers strongly elevated cellular adhesion, proliferation, and in vitro wound healing features compared to PCL nanofibers. According to obtained results it is assumed that newly synthetized levan and PCL mediated nanofibers are very encouraging for healing tympanic membrane perforations.

Improving assay feasibility and biocompatibility of 3D cyclic olefin copolymer microwells by superhydrophilic modification via ultrasonic spray deposition of polyvinyl alcohol

Sample partitioning is a crucial step towards digitization of biological assays on polymer microfluidic platforms. However, effective liquid filling into microwells and long-term hydrophilicity remain a challenge in polymeric microfluidic devices, impeding the applicability in diagnostic and cell culture studies. To overcome this, a method to produce permanent superhydrophilic 3-dimensional microwells using cyclic olefin copolymer (COC) microfluidic chips is presented. The COC substrate is oxidized using UV treatment followed by ultrasonic spray coating of polyvinyl alcohol solution, offering uniform and long-term coating of high-aspect ratio microfeatures. The coated COC surfaces are UV-cured before bonding with a hydrophobic pressure-sensitive adhesive to drive selective filling into the wells. The surface hydrophilicity achieved using this method remains unchanged (water contact angle of 9°) for up to 6 months and the modified surface is characterized for physical (contact angle & surface energy, morphology, integrity of microfeatures and roughness), chemical composition (FTIR, Raman spectroscopy) and coating stability (pH, temperature, time). To establish the feasibility of the modified surface in biological applications, PVA-coated COC microfluidic chips are tested for DNA sensing (digital LAMP detection of CMV), and biocompatibility through protein adsorption and cell culture studies (cell adhesion, viability, and metabolic activity). Kidney and breast cells remained viable for the duration of testing (7 days) on this modified surface, and the coating did not affect the protein content, morphology or quality of the cultured cells. The ultrasonic spray coated system, coating with 0.25 % PVA for 15 cycles with 0.12 A current after UV oxidation, increased the surface energy of the COC (naturally hydrophobic) from 22.04 to 112.89 mJ/m2 and improved the filling efficiency from 40 % (native untreated COC) to 94 % in the microwells without interfering with the biocompatibility of the surface, proving to be an efficient, high-throughput and scalable method of microfluidic surface treatment for diagnostic and cell growth applications.

A 3D-printable gelatin/alginate/ε-poly-l-lysine hydrogel scaffold to enable porcine muscle stem cells expansion and differentiation for cultured meat development

The mass proliferation of seed cells and imitation of meat structures remain challenging for cell-cultured meat production. With excellent biocompatibility, high water content and porosity, hydrogels are frequently-studied materials for anchorage-dependent cell scaffolds in biotechnology applications. Herein, a scaffold based on gelatin/alginate/ε-Poly-l-lysine (GAL) hydrogel is developed for skeletal muscle cells, which has a great prospect in cell-cultured meat production. In this work, the hydrogel GAL-4:1, composed of gelatin (5 %, w/v), alginate (5 %, w/v) and ε-Poly-l-lysine (molar ratio vs. alginate: 4:1) is selected as cell scaffold based on Young's modulus of 11.29 ± 1.94 kPa, satisfactory shear-thinning property and suitable porous organized structure. The commercially available C2C12 mouse skeletal myoblasts and porcine muscle stem cells (PMuSCs), are cultured in the 3D-printed scaffold. The cells show strong ability of attachment, proliferation and differentiation after induction, showing high biocompatibility. Furthermore, the cellular bioprinting is performed with GAL-4:1 hydrogel and freshly extracted PMuSCs. The extracted PMuSCs exhibit high viability and display early myogenesis (desmin) on the 3D scaffold, suggesting the great potential of GAL hydrogel as 3D cellular constructs scaffolds. Overall, we develop a novel GAL hydrogel as a 3D-printed bioactive platform for cultured meat research.

Papain Covalent Immobilization in Bacterial Cellulose Films as a Wound Dressing

Ideally, the dressings used in the clinic have characteristics that help the wound closure process. Among several factors that affect the success of this healing process, there is debridement. It manages the wound bed components and the re-epithelialization process. Still, the property of debridement is not generally associated with dressings. Here, we show a chemically modified bacterial cellulose film conjugated to a proteolytic enzyme, papain, as a dressing with debridement properties. Bacterial cellulose films were reacted with a spacer derived from succinic acid and finally had this enzyme covalently immobilized in its structure by an amide bond. FT-IR and UV-vis showed bands typically of bioconjugated polymer. Enzymatic immobilization was very effective under the conditions applied with high yield (33% w/w), and these remained activated after the coupling reaction. The bacterial cellulose film with the enzyme papain attached to it was also very compatible with fibroblast cells, suggesting that it could be a promising wound dressing material for future research.

Human mesenchymal stromal cell adhesion and expansion on fluoropolymer surfaces modified with oxygen and nitrogen-rich plasma polymers

Fluorinated ethylene propylene (FEP) vessels are of significant interest for therapeutic cell biomanufacturing applications due to their chemical inertness, hydrophobic surface, and high oxygen permeability. However, these properties also limit the adhesion and survival of anchorage-dependent cells. Here, we develop novel plasma polymer coatings to modify FEP surfaces, enhancing the adhesion and expansion of human mesenchymal stromal cells (hMSCs). Similar to commercially available tissue culture polystyrene vessels, oxygen-rich or nitrogen-rich surface chemistries can be achieved using this approach. While steam sterilization increased the roughness of the coatings and altered the surface chemistry, the overall wettability and oxygen or nitrogen-rich nature of the coatings were maintained. In the absence of proteins during initial cell attachment, cells adhered to surfaces even in the presence of chelators, whereas adhesion was abrogated with chelator in a protein-containing medium, suggesting that integrin-mediated adhesion predominates over physicochemical tethering in normal protein-containing cell seeding conditions. Albumin adsorption was more elevated on nitrogen-rich coatings compared to the oxygen-rich coatings, which was correlated with a higher extent of hMSC expansion after 3 days. Both the oxygen and nitrogen-rich coatings significantly improved hMSC adhesion and expansion compared to untreated FEP. FEP surfaces with nitrogen-rich coatings were practically equivalent to commercially available standard tissue culture-treated polystyrene surfaces in terms of hMSC yields. Plasma polymer coatings show significant promise in expanding the potential usage of FEP-based culture vessels for cell therapy applications.

Tuning the efficacy of decellularized apple by coating with alginate/gelatin to behave as a bioscaffold for cultured meat production

Substantial efforts are underway to tackle the current challenges of sustainability and environmental impacts linked to orthodox animal agriculture. This had led to advancement in food innovation guiding the fabrication of edible scaffolds based cultured meat. This current research work aims to develop and validate a new approach in fabricating a 3D porous scaffold of decellularized apple coated with a polymer mixture of gelatin/alginate for cultivated meat production. The fabricated noncoated (A) and coated (CA) 3D scaffolds presented different ratios of pore sizes with the medium-sized pores (100-250 µm) being higher in the case of CA. The water absorption capacity of CA (∼64 %) was almost two folds compared to A (∼31 %) with delayed digestion in the presence of gastric simulated juice with or without pepsin. Both the scaffolds showed the capability to adhere and proliferate muscle satellite cells as single cell culture and muscle satellite along with NIH/3T3 fibroblast cells as co-culture. However, the CA scaffolds showed enhanced capability to adhere and proliferate the two cell lines on its surface compared to A. This work demonstrates an efficient way to fabricate decellularized plant scaffolds with high potential to be used in the production of cultured meat for the food industry.

In situ transient transfection of 3D cell cultures and tissues, a promising tool for tissue engineering and gene therapy

Various research fields use the transfection of mammalian cells with genetic material to induce the expression of a target transgene or gene silencing. It is a tool widely used in biological research, bioproduction, and therapy. Current transfection protocols are usually performed on 2D adherent cells or suspension cultures. The important rise of new gene therapies and regenerative medicine in the last decade raises the need for new tools to empower the in situ transfection of tissues and 3D cell cultures. This review will present novel in situ transfection methods based on a chemical or physical non-viral transfection of cells in tissues and 3D cultures, discuss the advantages and remaining gaps, and propose future developments and applications.

Composite microgranular scaffolds with surface modifications for improved initial osteoblastic cell proliferation

Polyester-based granular scaffolds are a potent material for tissue engineering due to their porosity, controllable pore size, and potential to be molded into various shapes. Additionally, they can be produced as composite materials, e.g., mixed with osteoconductive β-tricalcium phosphate or hydroxyapatite. Such polymer-based composite materials often happen to be hydrophobic, which disrupts cell attachment and decreases cell growth on the scaffold, undermining its primary function. In this work, we propose the experimental comparison of three modification techniques for granular scaffolds to increase their hydrophilicity and cell attachment. Those techniques include atmospheric plasma treatment, polydopamine coating, and polynorepinephrine coating. Composite polymer/β-tricalcium phosphate granules have been produced in a solution-induced phase separation (SIPS) process using commercially available biomedical polymers: poly(lactic acid), poly(lactic-co-glycolic acid), and polycaprolactone. We used thermal assembly to prepare cylindrical scaffolds from composite microgranules. Atmospheric plasma treatment, polydopamine coating, and polynorepinephrine coating showed similar effects on polymer composites' hydrophilic and bioactive properties. All modifications significantly increased human osteosarcoma MG-63 cell adhesion and proliferation in vitro compared to cells cultured on unmodified materials. In the case of polycaprolactone/β-tricalcium phosphate scaffolds, modifications were the most necessary, as unmodified polycaprolactone-based material disrupted the cell attachment. Modified polylactide/β-tricalcium phosphate scaffold supported excellent cell growth and showed ultimate compressive strength exceeding this of human trabecular bone. This suggests that all investigated modification techniques can be used interchangeably for increasing wettability and cell attachment properties of various scaffolds for medical applications, especially those with high surface and volumetric porosity, like granular scaffolds.

Exploring the potential of Halomonas levan and its derivatives as active ingredients in cosmeceutical and skin regenerating formulations

Demand on natural products that contain biological ingredients mimicking growth factors and cytokines made natural polysaccharides popular in pharmaceutical and cosmetic industries. Levan is the β-(2-6) linked, nontoxic, biocompatible, water-soluble, film former fructan polymer that has diverse applications in pharmacy and cosmeceutical industries with its moisturizing, whitening, anti-irritant, anti-aging and slimming activities. Driven by the limited reports on few structurally similar levan polymers, this study presents the first systematic investigation on the effects of structurally different extremophilic Halomonas levan polysaccharides on human skin epidermis cells. In-vitro experiments with microbially produced linear Halomonas levan (HL), its hydrolyzed, (hHL) and sulfonated (ShHL) derivatives as well as enzymatically produced branched levan (EL) revealed increased keratinocyte and fibroblast proliferation (113-118 %), improved skin barrier function through induced expressions of involucrin (2.0 and 6.43 fold changes for HL and EL) and filaggrin (1.74 and 3.89 fold changes for hHL and ShHL) genes and increased type I collagen (2.63 for ShHL) and hyaluronan synthase 3 (1.41 for HL) gene expressions together with fast wound healing ability within 24 h (100 %, HL) on 2D wound models clearly showed that HL and its derivatives have high potential to be used as natural active ingredients in cosmeceutical and skin regenerating formulations.

Enhanced treatment of landfill leachate by biochar-based aerobic denitrifying bacteria functional microbial materials: Preparation and performance

Objective

In this work, polyvinyl alcohol (PVA) and sodium alginate (SA) were used as entrapped carriers and Artemisia argyi stem biochar (ABC) was used as an absorption carrier to immobilize aerobic denitrifying bacteria screened from landfill leachate, thus a new carbon-based functional microbial material (PVA/SA/ABC@BS) was successfully prepared.

Methods

The structure and characteristics of the new material were revealed by using a scanning electron microscope and Fourier transform infrared spectroscopy, and the performance of the material for treating landfill leachate under different working conditions was studied.

Results

ABC had abundant pore structures and that the surface contained many oxygen-containing functional groups, carboxyl groups, and amide groups, etc. and it had good absorbing performance and strong acid and alkali buffering capacity, which was beneficial to the adhesion and proliferation of microorganisms. After adding ABC as a composite carrier, the damage rate of immobilized particles was decreased by 1.2%, and the acid stability, alkaline stability, and mass transfer performance were increased by 9.00, 7.00, and 56%, respectively. When the dosage of PVA/SA/ABC@BS was 0.017g/ml, the removal rates of nitrate nitrogen (NO₃ ^--N) and ammonia nitrogen (NH₄ ⁺-N) were the highest, which were 98.7 and 59.4%, respectively. When the pH values were 11, 7, 1, and 9, the removal rates of chemical oxygen demand (COD), NO₃ ^--N, nitrite nitrogen (NO₂ ^--N) and NH₄ ⁺-N reached the maximum values, which were 14.39, 98.38, 75.87, and 79.31%, respectively. After PVA/SA/ABC@BS was reused in 5 batches, the removal rates of NO₃ ^--N all reached 95.50%.

Conclusion

PVA, SA and ABC have excellent reusability for immobilization of microorganisms and degradation of nitrate nitrogen. This study can provide some guidance for the great application potential of immobilized gel spheres in the treatment of high concentration organic wastewater.

Study on the mechanism of biochar affecting the effectiveness of phosphate solubilizing bacteria

Low phosphorus utilization and phosphorus fertilizer pollution are serious issues primarily affecting soil health. To investigate the effects of biochar on the growth, phosphorus solubilization, and metabolites of phosphorus-solubilizing bacteria (PSB), rice husk biochar (RH) and rice straw biochar (RS) were incubated with Bacillus megatherium (BM1) and Bacillus mucilaginosus (BM2), respectively. The highest phosphorus solubilization was observed in BM2 following the addition of RS. The dissolved amount of phosphorus was 244.99 mg/L, which was 43.86% higher than that of the control group. Hence, biochar can improve the phosphorus solubilization capacity of PSB by affecting the organic acid and polysaccharide contents, and phosphatase activity secreted by the PSB, as the porous structure and surface characteristics of biochar ensured the adsorption of PSB. This study can help improve the functional activity of PSB and provide basis for improving the utilization of soil phosphorus, which in turn, aid in the development of biochar-based microbial fertilizers.

Photo-reactive polymers for the immobilisation of epidermal growth factors

Photo-reactive polymers are important for biomaterials, including devices with a 3D-structure. Here, different types of photo-reactive polymers were prepared and utilised for immobilisation of growth factors. They were synthesised by conjugation of gelatin with the azidophenyl group or by copolymerisation of the azidophenyl group-coupled methacrylate with poly(ethylene glycol) methacrylate. The azidophenyl content and the zeta potential of the prepared polymers were measured. After spin coating of polymers, the thickness and the water contact angle of coated layers were measured. The amount of the immobilised epidermal growth factor (EGF) was determined using fluorescence labelling. Cell adhesion responded to the nature of photo-reactive polymers but did not depend on the immobilised EGF. However, cell growth was dependent on the amount of immobilised EGF and was significantly affected by the nature of photo-reactive polymers. The study shows that the properties of the photo-immobilisation matrix significantly influence the biological activity.

Long-Term In Vitro Assessment of Biodegradable Radiopaque Composites for Fiducial Marker Fabrication

Biodegradable polymer-based composite materials may be successfully utilised to fabricate fiducial markers (FMs), which are intended to precisely label tumour margins during image-guided surgery or radiotherapy. However, due to matrix degradability, the stability of the functional properties of FMs depends on the chosen polymer. Thus, this study aimed to investigate novel radiopaque composites which varied in the polymeric matrix-polycaprolactone (PCL), poly(L-lactide-co-caprolactone) (P[LAcoCL]) with two molar ratios (70:30 and 85:15), and poly(L-lactide-co-glycolide) (with molar ratio 82:18). The radiopaque component of the materials was a mixture of barium sulphate and hydroxyapatite. The changes in water contact angle, stiffness, and radiopacity occurring during the 24-week-long degradation experiment were examined for the first time. This study comprehensively analyses the microstructural causes of composites behaviour within degradation experiments using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permitted chromatography (GPC), and scanning electron microscopy (SEM). The obtained results suggest that the utilized biodegradable matrix plays an essential role in radiopaque composite properties and stability thereof. This long-term in vitro assessment enabled a comparison of the materials and aided in choosing the most favourable composite for FMs' fabrication.

Surface Modification of PHBV Fibrous Scaffold via Lithium Borohydride Reduction

In this study, lithium borohydride (LiBH₄) reduction was used to modify the surface chemistry of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibers. Although the most common reaction employed in the surface treatment of polyester materials is hydrolysis, it is not suitable for fiber modification of bacterial polyesters, which are highly resistant to this type of reaction. The use of LiBH₄ allowed the formation of surface hydroxyl groups under very mild conditions, which was crucial for maintaining the fibers' integrity. The presence of these groups resulted in a noticeable improvement in the surface hydrophilicity of PHBV, as revealed by contact angle measurements. After the treatment with a LiBH₄ solution, the electrospun PHBV fibrous mat had a significantly greater number of viable osteoblast-like cells (SaOS-2 cell line) than the untreated mat. Moreover, the results of the cell proliferation measurements correlated well with the observed cell morphology. The most flattened SaOS-2 cells were found on the surface that supported the best cell attachment. Most importantly, the results of our study indicated that the degree of surface modification could be controlled by changing the degradation time and concentration of the borohydride solution. This was of great importance since it allowed optimization of the surface properties to achieve the highest cell-proliferation capacity.

Edible films for cultivated meat production

Biomaterial scaffolds are critical components in cultivated meat production for enabling cell adhesion, proliferation, differentiation and orientation. Currently, there is limited information on the fabrication of edible/biodegradable scaffolds for cultivated meat applications. In the present work, several abundant, naturally derived biomaterials (gelatin, soy, glutenin, zein, cellulose, alginate, konjac, chitosan) were fabricated into films without toxic cross-linking or stabilizing agents. These films were investigated for support of the adhesion, proliferation and differentiation of murine and bovine myoblasts. These biomaterials supported cell viability, and the protein-based films showed better cell adhesion than the polysaccharide-based films. Surface patterns induced cell alignment and guided myoblast differentiation and organization on the glutenin and zein films. The mechanical properties of the protein films were also assessed and suggested that a range of properties can be achieved to meet food-related goals. Overall, based on adherence, proliferation, differentiation, mechanics, and material availability, protein-based films, particularly glutenin and zein, showed the most promise for cultivated meat applications. Ultimately, this work presents a comparison of suitable biomaterials for cultivated meat applications and suggests future efforts to optimize scaffolds for efficacy and cost.

Attachment of endothelial colony-forming cells onto a surface bearing immobilized anti-CD34 antibodies: Specific CD34 binding versus nonspecific binding

Cardiovascular disease is a leading cause of death worldwide; however, despite substantial advances in medical device surface modifications, no synthetic coatings have so far matched the native endothelium as the optimal hemocompatible surface for blood-contacting implants. A promising strategy for rapid restoration of the endothelium on blood-contacting biomedical devices entails attracting circulating endothelial cells or their progenitors, via immobilized cell-capture molecules; for example, anti-CD34 antibody to attract CD34+ endothelial colony-forming cells (ECFCs). Inherent is the assumption that the cells attracted to the biomaterial surface are bound exclusively via a specific CD34 binding. However, serum proteins might adsorb in-between or on the top of antibody molecules and attract ECFCs via other binding mechanisms. Here, we studied whether a surface with immobilized anti-CD34 antibodies attracts ECFCs via a specific CD34 binding or a nonspecific (non-CD34) binding. To minimize serum protein adsorption, a fouling-resistant layer of hyperbranched polyglycerol (HPG) was used as a "blank slate," onto which anti-CD34 antibodies were immobilized via aldehyde-amine coupling reaction after oxidation of terminal diols to aldehydes. An isotype antibody, mIgG1, was surface-immobilized analogously and was used as the control for antigen-binding specificity. Cell binding was also measured on the HPG hydrogel layer before and after oxidation. The surface analysis methods, x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, were used to verify the intended surface chemistries and revealed that the surface coverage of antibodies was sparse, yet the anti-CD34 antibody grafted surface-bound ECFCs very effectively. Moreover, it still captured the ECFCs after BSA passivation. However, cells also attached to oxidized HPG and immobilized mIgG1, though in much lower amounts. While our results confirm the effectiveness of attracting ECFCs via surface-bound anti-CD34 antibodies, our observation of a nonspecific binding component highlights the importance of considering its consequences in future studies.

Static and Dynamic Biomaterial Engineering for Cell Modulation

In the biological microenvironment, cells are surrounded by an extracellular matrix (ECM), with which they dynamically interact during various biological processes. Specifically, the physical and chemical properties of the ECM work cooperatively to influence the behavior and fate of cells directly and indirectly, which invokes various physiological responses in the body. Hence, efficient strategies to modulate cellular responses for a specific purpose have become important for various scientific fields such as biology, pharmacy, and medicine. Among many approaches, the utilization of biomaterials has been studied the most because they can be meticulously engineered to mimic cellular modulatory behavior. For such careful engineering, studies on physical modulation (e.g., ECM topography, stiffness, and wettability) and chemical manipulation (e.g., composition and soluble and surface biosignals) have been actively conducted. At present, the scope of research is being shifted from static (considering only the initial environment and the effects of each element) to biomimetic dynamic (including the concepts of time and gradient) modulation in both physical and chemical manipulations. This review provides an overall perspective on how the static and dynamic biomaterials are actively engineered to modulate targeted cellular responses while highlighting the importance and advance from static modulation to biomimetic dynamic modulation for biomedical applications.

The electrochemical potential is a key parameter for cell adhesion and proliferation on carbon surface

The Nernst potential of the support/cell interface is suspected to play a key role in cell adhesion and proliferation. However, the studies that have addressed this topic have generally varied the electrochemical potential of the interface by comparing different materials or by varying the chemical composition of the surface coating. It is consequently hard to definitively separate the actual effect of the potential from possible side-effects due to differences in the surface composition or topography. Here, a 3-electrode set-up was used to apply different values of potential to identical carbon electrodes. Potentials were applied in the range -200 to 400 mV vs. silver pseudo-reference (SPR), i.e. 90 to 690 mV/SHE, to screen-printed carbon electrodes used to grow Vero or Raw 264.7 cell lines. Values up to 200 mV/SPR prohibited cell adhesion and even caused detachment of cells that were previously adhered. The value of 400 mV/DRP allowed cell adhesion and proliferation, leading to confluent and sometimes very compact mats. The zero charge potential, measured around 200 mV/DRP, showed that the drastic effect of the applied potential was probably due to the negative/positive switch of the surface charge.

Aminolysis as a surface functionalization method of aliphatic polyester nonwovens: impact on material properties and biological response

Aminolysis treatment improves L929 cell–scaffold interaction. It is possible to reach compromise between the concentration of NH2 groups and mechanical properties change.

Resveratrol-Loaded Levan Nanoparticles Produced by Electrohydrodynamic Atomization Technique

Considering the significant advances in nanostructured systems in various biomedical applications and the escalating need for levan-based nanoparticles as delivery systems, this study aimed to fabricate levan nanoparticles by the electrohydrodynamic atomization (EHDA) technique. The hydrolyzed derivative of levan polysaccharide from Halomonas smyrnensis halophilic bacteria, hydrolyzed Halomonas levan (hHL), was used. Nanoparticles were obtained by optimizing the EHDA parameters and then they were characterized in terms of morphology, molecular interactions, drug release and cell culture studies. The optimized hHL and resveratrol (RS)-loaded hHL nanoparticles were monodisperse and had smooth surfaces. The particle diameter size of hHL nanoparticles was 82.06 ± 15.33 nm. Additionally, release of RS from the fabricated hHL nanoparticles at different pH conditions were found to follow the first-order release model and hHL with higher RS loading showed a more gradual release. In vitro biocompatibility assay with human dermal fibroblast cell lines was performed and cell behavior on coated surfaces was observed. Nanoparticles were found to be safe for healthy cells. Consequently, the fabricated hHL-based nanoparticle system may have potential use in drug delivery systems for wound healing and tissue engineering applications and surfaces could be coated with these electrosprayed particles to improve cellular interaction.

Engineering 3D Cortical Spheroids for an In Vitro Ischemic Stroke Model

Three-dimensional (3D) spheroids composed of brain cells have shown great potential to mimic the pathophysiology of the brain. However, a 3D spheroidal brain-disease model for cerebral ischemia has not been reported. This study investigated an ultralow attachment (ULA) surface-mediated formation of 3D cortical spheroids using primary rat cortical cells to recapitulate the cerebral ischemic responses in stroke by oxygen-glucose deprivation-reoxygenation (OGD-R) treatment. Comparison between two-dimensional (2D) and 3D cell culture models confirmed the better performance of the 3D cortical spheroids as normal brain models. The cortical cells cultured in 3D maintained their healthy physiological morphology of a less activated state and suppressed mRNA expressions of pathological stroke markers, S100B, IL-1β, and MBP, selected based on in vivo stroke model. Interestingly, the spheroids formed on the ULA surface exhibited striking aggregation dynamics involving active cell-substrate interactions, whereas those formed on the agarose surface aggregated passively by the convective flow of the media. Accordingly, ULA spheroids manifested a layered arrangement of neurons and astrocytes with higher expressions of integrin β1, integrin α5, N-cadherin, and fibronectin than the agarose spheroids. OGD-R-induced stroke model of the ULA spheroids successfully mimicked the ischemic response as evidenced by the upregulated mRNA expressions of the key markers for stroke, S100B, IL-1β, and MBP. Our study suggested that structurally and functionally distinct cortical spheroids could be generated by simply tuning the cell-substrate binding activities during dynamic spheroidal formation, which should be an essential factor to consider in establishing a brain-disease model.

Responsive Polyesters with Alkene and Carboxylic Acid Side-Groups for Tissue Engineering Applications

Main chain polyesters have been extensively used in the biomedical field. Despite their many advantages, including biocompatibility, biodegradability, and others, these materials are rather inert and lack specific functionalities which will endow them with additional biological and responsive properties. In this work, novel pH-responsive main chain polyesters have been prepared by a conventional condensation polymerization of a vinyl functionalized diol with a diacid chloride, followed by a photo-induced thiol-ene click reaction to attach functional carboxylic acid side-groups along the polymer chains. Two different mercaptocarboxylic acids were employed, allowing to vary the alkyl chain length of the polymer pendant groups. Moreover, the degree of modification, and as a result, the carboxylic acid content of the polymers, was easily tuned by varying the irradiation time during the click reaction. Both these parameters, were shown to strongly influence the responsive behavior of the polyesters, which presented adjustable pKα values and water solubilities. Finally, the difunctional polyesters bearing the alkene and carboxylic acid functionalities enabled the preparation of cross-linked polyester films by chemically linking the pendant vinyl bonds on the polymer side groups. The biocompatibility of the cross-linked polymers films was assessed in L929 fibroblast cultures and showed that the cell viability, proliferation, and attachment were greatly promoted on the polyester surface, bearing the shorter alkyl chain length side groups and the higher fraction of carboxylic acid functionalities.

Scaffolds from Self-Assembling Tetrapeptides Support 3D Spreading, Osteogenic Differentiation, and Angiogenesis of Mesenchymal Stem Cells

The apparent rise of bone disorders demands advanced treatment protocols involving tissue engineering. Here, we describe self-assembling tetrapeptide scaffolds for the growth and osteogenic differentiation of human mesenchymal stem cells (hMSCs). The rationally designed peptides are synthetic amphiphilic self-assembling peptides composed of four amino acids that are nontoxic. These tetrapeptides can quickly solidify to nanofibrous hydrogels that resemble the extracellular matrix and provide a three-dimensional (3D) environment for cells with suitable mechanical properties. Furthermore, we can easily tune the stiffness of these peptide hydrogels by just increasing the peptide concentration, thus providing a wide range of peptide hydrogels with different stiffnesses for 3D cell culture applications. Since successful bone regeneration requires both osteogenesis and vascularization, our scaffold was found to be able to promote angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro. The results presented suggest that ultrashort peptide hydrogels are promising candidates for applications in bone tissue engineering.

Unraveling the surface properties of PMMA/azobenzene blends as coating films with photoreversible surface polarity

Various reports demonstrated that azobenzene derivatives are the chromophore of choice in photoresponsive surfaces showing reversible surface polarity. Hitherto the surface study of coating films based on polymer/azobenzene blends using contact angle measurements remained unexplored. To provide insight into the surface polarity of polymer/dye blend films, poly(methyl methacrylate) (PMMA) blends containing photoresponsive 4-hydroxy-4′-methylazobenzene (AZO1) and 4,4′-dimethylazobenzene (AZO2) as coating films on clear glass substrates are investigated in this work. Contact angle measurements were carried out to unravel the role of substituents in the surface polarity and the orientation of chromophores in the coating matrices before and after UV light (λ_max = 365 nm) irradiation. Changes in water contact angles measured on the PMMA/azobenzene coating films indicated that the surface polarity is reversible as the chromophores underwent reversible trans–cis isomerisation. It has been revealed that the repeated trans–cis isomerisation led to the random reorientation and arrangement of chromophores in PMMA/AZO1 coating films. Then, to indicate the possibility of the disruption of interfacial interactions due to the repeated trans–cis isomerisation processes, as a proof of concept experiment, it is shown that the commercial acrylic-based pressure-sensitive sticker which adhered strongly to the PMMA/AZO1(13) coating film is peeled off from the coating surface after being subjected to a cycle of UV light irradiation for 12 hours, followed by dark conditions for another 12 hours within 14 days. The proof of concept study will lead to more development of smart photoresponsive coating films using simple polymer/dye blends.

A repeated trans–cis isomerisation led to the random reorientation and arrangement of chromophores in PMMA/azobenzene blends as coating films.

Preparation of chitosan biguanidine/PANI-containing self-healing semi-conductive waterborne scaffolds for bone tissue engineering

Electrically conducting self-healing scaffolds are known as a new series of intelligent biomaterial for regulating Human Adipose Mesenchymal Stem Cells biological behaviors, especially their differentiation to bone cells. Herein, we developed a novel hydrophilic semi-conductive chitosan derivative (CP) and loaded it into the self-healing waterborne polyurethane structure, as a new osteogenic agent. The fabricated scaffolds exhibited excellent shape memory properties with shape fixity (> 97 %) and shape recovery ratio (> 98 %) with excellent self-healing value (> 93 %) at a temperature close to the body temperature. The results of MTT, cell attachment, alkaline phosphatase activity, and alizarin red staining analysis demonstrated that the CP-contained scaffolds promote proliferation of hADSCs and matrix mineralization. Also, by introducing the CP the gene expression level of COL-1, ALP, RUNX2, and OCN were significantly enhanced, in line with matrix mineralization. These multifunctional engineered constructs are promising biomaterials for repairing various bone defects.

Integrating biomaterials and food biopolymers for cultured meat production

Cultured meat has recently achieved mainstream prominence due to the emergence of societal and industrial interest. In contrast to animal-based production of traditional meat, the cultured meat approach entails laboratory cultivation of engineered muscle tissue. However, bioengineers have hitherto engineered tissues to fulfil biomedical endpoints, and have had limited experience in engineering muscle tissue for its post-mortem traits, which broadly govern consumer definitions of meat quality. Furthermore, existing tissue engineering approaches face fundamental challenges in technical feasibility and industrial scalability for cultured meat production. This review discusses how animal-based meat production variables influence meat properties at both the molecular and functional level, and whether current cultured meat approaches recapitulate these properties. In addition, this review considers how conventional meat producers employ exogenous biopolymer-based meat ingredients and processing techniques to mimic desirable meat properties in meat products. Finally, current biomaterial strategies for engineering muscle and adipose tissue are surveyed in the context of emerging constraints that pertain to cultured meat production, such as edibility, sustainability and scalability, and potential areas for integrating biomaterials and food biopolymer approaches to address these constraints are discussed. STATEMENT OF SIGNIFICANCE: Laboratory-grown or cultured meat has gained increasing interest from industry and the public, but currently faces significant impediment to market feasibility. This is due to fundamental knowledge gaps in producing realistic meat tissues via conventional tissue engineering approaches, as well as translational challenges in scaling up these approaches in an efficient, sustainable and high-volume manner. By defining the molecular basis for desirable meat quality attributes, such as taste and texture, and introducing the fundamental roles of food biopolymers in mimicking these properties in conventional meat products, this review aims to bridge the historically disparate fields of meat science and biomaterials engineering in order to inspire potentially synergistic strategies that address some of these challenges.

Biomaterial Properties Modulating Bone Regeneration

Biomaterial scaffolds have been gaining momentum in the past several decades for their potential applications in the area of tissue engineering. They function as three-dimensional porous constructs to temporarily support the attachment of cells, subsequently influencing cell behaviors such as proliferation and differentiation to repair or regenerate defective tissues. In addition, scaffolds can also serve as delivery vehicles to achieve sustained release of encapsulated growth factors or therapeutic agents to further modulate the regeneration process. Given the limitations of current bone grafts used clinically in bone repair, alternatives such as biomaterial scaffolds have emerged as potential bone graft substitutes. This review summarizes how physicochemical properties of biomaterial scaffolds can influence cell behavior and its downstream effect, particularly in its application to bone regeneration.

Effects of physicochemical properties of polyacrylamide (PAA) and (polydimethylsiloxane) PDMS on cardiac cell behavior

In vitro cell culture is commonly applied in laboratories around the world. Cultured cells are either of primary origin or established cell lines. Such transformed cell lines are increasingly replaced by pluripotent stem cell derived organotypic cells with more physiological properties. The quality of the culture conditions and matrix environment is of considerable importance in this regard. In fact, mechanical cues of the extracellular matrix have substantial effects on the cellular physiology. This is especially true if contractile cells such as cardiomyocytes are cultured. Therefore, elastic biomaterials have been introduced as scaffolds in 2D and 3D culture models for different cell types, cardiac cells among them. In this review, key aspects of cell-matrix interaction are highlighted with focus on cardiomyocytes and chemical properties as well as strengths and potential pitfalls in using two commonly applied polymers for soft matrix engineering, polyacrylamide (PAA) and polydimethylsiloxane (PDMS) are discussed.

Cell Behavior of Primary Fibroblasts and Osteoblasts on Plasma-Treated Fluorinated Polymer Coated with Honeycomb Polystyrene

The development of new biocompatible polymer substrates is still of interest to many research teams. We aimed to combine a plasma treatment of fluorinated ethylene propylene (FEP) substrate with a technique of improved phase separation. Plasma exposure served for substrate activation and modification of surface properties, such as roughness, chemistry, and wettability. The treated FEP substrate was applied for the growth of a honeycomb-like pattern from polystyrene solution. The properties of the pattern strongly depended on the primary plasma exposure of the FEP substrate. The physico-chemical properties such as changes of the surface chemistry, wettability, and morphology of the prepared pattern were determined. The cell response of primary fibroblasts and osteoblasts was studied on a honeycomb pattern. The prepared honeycomb-like pattern from polystyrene showed an increase in cell viability and a positive effect on cell adhesion and proliferation for both primary fibroblasts and osteoblasts.

Effects of surface condition of conductive electrospun nanofiber mats on cell behavior for nerve tissue engineering

Electrospun nanofibrous scaffold is a promising implant for peripheral nerve regeneration. Herein, to investigate the effect of surface morphological features and electrical properties of scaffolds on nerve cell behavior, we modified electrospun cellulose (EC) fibrous mats with four kind of soluble conductive polymers derivates (poly (N-(methacryl ethyl) pyrrole) (PMAEPy), poly (N-(2-hydroxyethyl) pyrrole) (PHEPy), poly (3-(Ethoxycarbonyl) thiophene) (P3ECT) and poly (3-thiophenethanol) (P3TE)) by an in-situ polymerization method. The morphological characterization showed that conductive polymers formed aggregated nanoparticles and coatings on the EC nanofibers with the increased fiber diameter further affected the surface properties. Compared with pure EC scaffold, more PC12 cells were adhered and grown on modified mats, with more integral and clearer cell morphology. The results of protein adsorption study indicated that modified EC mats could provide more protein adsorption site due to their characteristic surface morphology, which is beneficial to cell adhesion and growth. The results in this study suggested that these conductive polymers modified scaffolds with special surface morphology have potential applications in neural tissue engineering.

Engineered Microsystems for Spheroid and Organoid Studies

3D in vitro model systems such as spheroids and organoids provide an opportunity to extend the physiological understanding using recapitulated tissues that mimic physiological characteristics of in vivo microenvironments. Unlike 2D systems, 3D in vitro systems can bridge the gap between inadequate 2D cultures and the in vivo environments, providing novel insights on complex physiological mechanisms at various scales of organization, ranging from the cellular, tissue-, to organ-levels. To satisfy the ever-increasing need for highly complex and sophisticated systems, many 3D in vitro models with advanced microengineering techniques have been developed to answer diverse physiological questions. This review summarizes recent advances in engineered microsystems for the development of 3D in vitro model systems. The relationship between the underlying physics behind the microengineering techniques, and their ability to recapitulate distinct 3D cellular structures and functions of diverse types of tissues and organs are highlighted and discussed in detail. A number of 3D in vitro models and their engineering principles are also introduced. Finally, current limitations are summarized, and perspectives for future directions in guiding the development of 3D in vitro model systems using microengineering techniques are provided.

Detection of large extracellular silver nanoparticle rings observed during mitosis using darkfield microscopy

During studies on the absorption and interactions between silver nanoparticles and mammalian cells grown in vitro it was observed that large extracellular rings of silver nanoparticles were deposited on the microscope slide, many located near post-mitotic cells. Silver nanoparticles (AgNP, 80nm), coated with citrate, were incubated at concentrations of 0.3 to 30 μg/ml with a human-derived culture of retinal pigment epithelial cells (ARPE-19) and observed using darkfield and fluorescent microscopy, 24 h after treatment. Approximately cell-sized extracellular rings of deposited AgNP were observed on the slides among a field of dispersed individual AgNP. The mean diameter of 45 nanoparticles circles was 62.5 +/-12 microns. Ring structures were frequently observed near what appeared to be post-mitotic daughter cells, giving rise to the possibility that cell membrane fragments were deposited on the slide during mitosis, and those fragments selectively attracted and retained silver nanoparticles from suspension in the cell culture medium. These circular structures were observable for the following technical reasons: 1) darkfield microscope could observe single nanoparticles below 100 nm in size, 2) a large concentration (108 and 109) of nanoparticles was used in these experiments 3) negatively charged nanoparticles were attracted to adhesion membrane proteins remaining on the slide from mitosis. The observation of silver nanoparticles attracted to apparent remnants of cellular mitosis could be a useful tool for the study of normal and abnormal mitosis.

Enhancement of Intracellular Calcium Ion Mobilization by Moderately but Not Highly Positive Material Surface Charges

Electrostatic forces at the cell interface affect the nature of cell adhesion and function; but there is still limited knowledge about the impact of positive or negative surface charges on cell-material interactions in regenerative medicine. Titanium surfaces with a variety of zeta potentials between −90 mV and +50 mV were generated by functionalizing them with amino polymers, extracellular matrix proteins/peptide motifs and polyelectrolyte multilayers. A significant enhancement of intracellular calcium mobilization was achieved on surfaces with a moderately positive (+1 to +10 mV) compared with a negative zeta potential (−90 to −3 mV). Dramatic losses of cell activity (membrane integrity, viability, proliferation, calcium mobilization) were observed on surfaces with a highly positive zeta potential (+50 mV). This systematic study indicates that cells do not prefer positive charges in general, merely moderately positive ones. The cell behavior of MG-63s could be correlated with the materials’ zeta potential; but not with water contact angle or surface free energy. Our findings present new insights and provide an essential knowledge for future applications in dental and orthopedic surgery.

Manganese accumulation on pipe surface in chlorinated drinking water distribution system: Contributions of physical and chemical pathways

The accumulation of manganese in drinking water distribution systems often causes problems of "black water" in customers' taps. In this study, Mn accumulation onto a pipe surface under chlorinated conditions was investigated by focusing on the different states of Mn in the water. Lab-scale experiments suggested that the accumulation process included both the attachment of particulate Mn onto the surface (i.e., physical pathway) and the autocatalytic oxidation of Mn ions on the surface (i.e., chemical pathway). Based on the experimental results, a numerical model of Mn accumulation on the pipe surface via the two pathways was established. According to the model predictions, the physical pathway contributed less than the chemical pathway over time since the latter accelerated as Mn accumulation increased. The chemical pathway contributed 94% when the concentration of total Mn was 10 µg/L throughout the experiment, but only 67% when the concentration was 100 µg/L. Thus, the chemical pathway was more important for low concentrations of total Mn. In addition, the type of pipe materials used only influenced the physical pathway, while the presence of bromide directly enhanced the chemical pathway. In conclusion, limiting the chemical pathway was suggested as an effective strategy for reducing Mn accumulation during long-term operation, which is achieved by controlling the state of Mn in finished water.

Effects of biochar properties on the bioremediation of the petroleum-contaminated soil from a shale-gas field

The characteristics of biochar carriers prepared from different biomass (corncob, straw, and sawdust) were investigated, and the bioremediation performance of the biochar through microbial immobilization was analyzed. Corncob biochar had the highest specific surface area (157.11-312.30 m² g^-1) among the different biomass, and the specific surface area and total pore volume reached the maximum at 500 °C. The pore size was primarily micropore, which aided to the fixation of microorganisms and the adsorption of petroleum pollutants. With increased pyrolysis temperature, the polar functional groups in biochar decreased, and the aromatic functional groups gradually increased, thereby benefiting the adsorption of hydrophobic organic compounds. Corncob biochar had the highest zeta potential, i.e., from - 30.95 to - 6.43 mV, conducive to the electrostatic adsorption between carrier and microorganism. The highest oil-removal and microbial-immobilization rates of biochar CC500 (with corncob pyrolyzed at 500 °C) were about 70.7% and 71.2%, respectively. A strong recovery of microbial growth activity was also observed; recovery was 83.38% compared with free bacteria, and the fixed microorganisms reached logarithmic-growth period at 8-18 h.

Persistence of plastic debris and its colonization by bacterial communities after two decades on the abyssal seafloor

The fate of plastic debris entering the oceans is largely unconstrained. Currently, intensified research is devoted to the abiotic and microbial degradation of plastic floating near the ocean surface for an extended period of time. In contrast, the impacts of environmental conditions in the deep sea on polymer properties and rigidity are virtually unknown. Here, we present unique results of plastic items identified to have been introduced into deep-sea sediments at a water depth of 4150 m in the eastern equatorial Pacific Ocean more than two decades ago. The results, including optical, spectroscopic, physical and microbial analyses, clearly demonstrate that the bulk polymer materials show no apparent sign of physical or chemical degradation. Solely the polymer surface layers showed reduced hydrophobicity, presumably caused by microbial colonization. The bacterial community present on the plastic items differed significantly (p < 0.1%) from those of the adjacent natural environment by a dominant presence of groups requiring steep redox gradients (Mesorhizobium, Sulfurimonas) and a remarkable decrease in diversity. The establishment of chemical gradients across the polymer surfaces presumably caused these conditions. Our findings suggest that plastic is stable over extended times under deep-sea conditions and that prolonged deposition of polymer items at the seafloor may induce local oxygen depletion at the sediment-water interface.

Predictive Modeling of the In Vitro Responses of Preosteoblastic MC3T3-E1 Cells on Polymeric Surfaces Using Fourier Transform Infrared Spectroscopy

Biomaterials' surface properties elicit diverse cellular responses in biomedical and biotechnological applications. Predicting the cell behavior on a polymeric surface is an ongoing challenge due to its complexity. This work proposes a novel modeling methodology based on attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Spectra were collected on wetted polymeric surfaces to incorporate both surface chemistry and information on water-polymer interactions. Results showed that predictive models built with spectra from wetted surfaces ("wet spectra") performed much better than models built using spectra acquired from dry surfaces ("dry spectra"), suggesting that the water-polymer interaction is critically important to the prediction of subsequent cell behavior. The best model was seen to predict total area of focal adhesions with coefficient of determination for prediction (R²_P) of 0.94 and root-mean-square errors of prediction (RMSEP) of 4.03 μm² when tested on an independent experimental set. This work offers new insights into our understanding of cell-biomaterial interactions. The presence of carboxyl groups in polymers promoted larger adhesion areas, yet the formation of carbonyl-to-water interaction decreased adhesion areas. Surface wettability, which was related to the water-polymer interaction, was proven to highly influence cell adhesion. The good predictive ability opens new possibilities for high throughput monitoring of cell attachment on polymeric substrates.

Lentivirus Manufacturing Process for Primary T-Cell Biofactory Production

A process for maximizing the titer of lentivirus particles, deemed to be a necessity for transducing primary cells, is developed. Lentivirus particles, with a set of transgenes encoding an artificial cell-signaling pathway, are used to transform primary T cells as vectors for calibrated synthesis of desired proteins in situ, that is, T-cell biofactory cells. The process is also used to generate primary T cells expressing antigen-specific chimeric antigen receptors, that is, CAR T cells. The two differently engineered primary T cells are expanded and validated for their respective functions, that is, calibrated synthesis of desired proteins upon engaging the target cells, which is specific for the T-cell biofactory cells, and cytolysis of the target cells common to both types of cells. The process is compliant with current Good Manufacturing Practices and can be used to support the scale-up for clinical translation.