Surface Nanoroughness Research Articles

Stochastic Nanoroughness Inhibits and Reverses Glial Scarring In Vitro and In Vivo via a Mechanobiology Paradigm Involving Piezo‐1

AbstractPhysical insult to the central nervous system (CNS) such as during electrode insertion leads to reactive astrogliosis which in turn contributes to glial scarring (GS). To date, reducing GS in these settings has focused on pharmacological agents and variations in electrode material composition or implantation procedures, and the role of electrode surface topography has remained unexplored. Since proteoglycans, a major component of GS tissue, possesses very well‐defined (nano) topography, a role for stochastic nanoroughness in glial scar formation is theorized. Using an in vitro system, we provide proof of concept that on substrates possessing stochastic nanoroughness corresponding to that of healthy astrocytes, glial scar formation is significantly inhibited, and more importantly, can be even reversed, and it involves signaling via the stretch‐activated cation channel Piezo‐1. In vivo studies reveal an absence of astrocytes aggregation along the electrode track of chronically implanted electrodes modified with stochastic surface nanoroughness, compared to non‐modified electrodes, while signal detection within the superior colliculus remains unaffected. These findings shedlight on the crucial role of stochastic biophysical cues in modulating GS formation; and offer a promising non‐chemical approach for engineering neural biomaterials interface for the CNS.

Comparative evaluation on surface nanohardness, surface microhardness, surface roughness, and wettability of plant-based organic nanoparticle reinforced polyetheretherketone as an implant material - An in vitro study.

Synthetic inorganic materials are commonly used as reinforcing agents in polyetheretherketone (PEEK) composite, whereas natural organic plant-based reinforcing agents are negligible. Surface hardness, roughness, and wettability are indicative factors of osseointegration behavior to be used as an implant material. This study evaluated micro surface hardness (MSH), nano surface hardness (NSH), surface roughness (SR), and contact angle (CA) of PEEK-Azadirachta indica reinforced at 10 wt%, 20 wt%, and 30 wt%. This was an in vitro study. Neem (A. indica) leaf nanoparticles were prepared and reinforced with PEEK powder at 10%, 20%, and 30% weight ratios by injection molding. Sixty specimens underwent the microhardness and CA testing using a digital microhardness tester, and CA goniometer, respectively, and later nanoindentation test to analyze the nanohardness and SR. A one-way ANOVA test with a 95% confidence interval for MSH and NSH, SR, and CA was performed on the samples. A post hoc Bonferroni test was conducted (α = 0.05) to compare the groups. There was a significant increase in nanohardness (P = 0.000) with zero difference in microhardness (P = 0.514). The addition of 10 wt%, 20 wt%, and 30 wt% nanoparticles increased the SR value of the pure PEEK from 273.19 nm to 284.10 (3.99%), 296.91 (8.68%), and 287.54 (5.24%), respectively. In the analysis of the CA, CA 20% shows the lowest angle (63.69) with the highest for control specimens (82.39). There is an increase in the PEEK composite SR with a decrease in CA. The addition of plant-derived nanoparticles into the PEEK matrix has a significant impact on the hardness and hydrophobicity enhancing cell growth and osteoblastic differentiation during osseointegration of dental implants.

Characterization of microstructural evolution of asphalt due to water damage using atomic force microscopy

Water erosion significantly impacts the microstructure of asphalt, which in turn affects the macroscopic performance of asphalt mixtures, such as reducing the adhesion between asphalt and aggregates as well as diminishing water stability. This study utilizes atomic force microscopy (AFM) to investigate the micromorphology, surface height distribution, nanosurface roughness, and microsurface energy of asphalt under different water immersion durations. Furthermore, it considers the influence of asphalt's penetration grade, oil source, and modifiers on the evolution of its microstructure. AFM analysis reveals that, with the exception of crumb rubber modified asphalt (PJ90/CR), the quantity and area of beelike structures in the asphalt decrease with increasing water immersion time. The surface height distribution of asphalt exhibits characteristics of an approximate normal distribution, with an increase in nanoscale heights over time due to the dissolution of surface components by water and physical erosion effects. Notably, the surface height of PJ90/CR and SBS modified asphalt (PJ90/SBS) is significantly lower than that of PJ90 before and after water immersion. Water damage causes asphalt surface particles to dissolve and re-aggregate, forming distinct nano-protrusions and pits, thereby increasing the asphalt's roughness. Among them, the roughness of SK90 are generally higher than those of SK70, with the average roughness (Ra) and peak-to-valley roughness (Rt) increasing by 28.93 % and 60.56 %, respectively, before immersion. Moreover, water damage leads to a decrease in the surface energy of asphalt to varying degrees, indicating that water more easily penetrates the asphalt film through adsorption and diffusion actions, altering its microstructure and, consequently, reducing its surface energy. The variations in the microstructure of SK90, Shell90, and PJ90 under different water immersion durations highlight the significance of oil source on asphalt performance.

Effect of sandblasting and acid surface pretreatment on the specific capacitance of CuO nanostructures grown by hot water treatment for supercapacitor electrode applications

Crystalline copper oxide (CuO) nanostructures with micro, nano, and micro-nano surface roughness were grown on Cu sheet substrates by a facile, scalable, low-cost, and low-temperature hot water treatment (HWT) method that simply involved immersing Cu sheet in DI water at 75 °C for 24 h without any chemical additives. Various morphological features and sizes of CuO nanostructures were tuned by using different surface pretreatment techniques including acid treatment, sandblasting, or a combination of those two. The surface morphology of the prepared samples was analyzed by scanning electron microscopy. The crystal structure of the CuO nanostructures was investigated by x-ray diffraction XRD and Raman spectroscopy. To study the pseudocapacitive behavior, their potential supercapacitor performance, and equivalent series resistance, electrochemical analysis was done by cyclic voltammetry and electrochemical impedance spectroscopy for all the CuO/Cu samples in 1 M of Na2SO4 electrolyte. Among all, the best supercapacitive performance was achieved for CuO/Cu samples pretreated with Sandblasting followed by Acid treatment resulting in a specific capacitance of about 104 F g−1. The electrode with the sandblasted + acid pretreated sample showed a maximum of ∼69% capacitive retention after 2000 consecutive cycles. Our results indicate that CuO nanostructures on Cu substrates prepared with different surface pretreatment conditions and grown by HWT can be promising electrodes for supercapacitor device applications.

Advanced Hollow Cathode Discharge Plasma Treatment of Unique Bilayered Fibrous Nerve Guidance Conduits for Enhanced/Oriented Neurite Outgrowth.

Despite all recent progresses in nerve tissue engineering, critical-sized nerve defects are still extremely challenging to repair. Therefore, this study targets the bridging of critical nerve defects and promoting an oriented neuronal outgrowth by engineering innovative nerve guidance conduits (NGCs) synergistically possessing exclusive topographical, chemical, and mechanical cues. To do so, a mechanically adequate mixture of polycaprolactone (PCL) and polylactic-co-glycolic acid (PLGA) was first carefully selected as base material to electrospin nanofibrous NGCs simulating the extracellular matrix. The electrospinning process was performed using a newly designed 2-pole air gap collector that leads to a one-step deposition of seamless NGCs having a bilayered architecture with an inner wall composed of highly aligned fibers and an outer wall consisting of randomly oriented fibers. This architecture is envisaged to afford guidance cues for the extension of long neurites on the underlying inner fiber alignment and to concurrently provide a sufficient nutrient supply through the pores of the outer random fibers. The surface chemistry of the NGCs was then modified making use of a hollow cathode discharge (HCD) plasma reactor purposely designed to allow an effective penetration of the reactive species into the NGCs to eventually treat their inner wall. X-ray photoelectron spectroscopy (XPS) results have indeed revealed a successful O2 plasma modification of the inner wall that exhibited a significantly increased oxygen content (24 → 28%), which led to an enhanced surface wettability. The treatment increased the surface nanoroughness of the fibers forming the NGCs as a result of an etching effect. This effect reduced the ultimate tensile strength of the NGCs while preserving their high flexibility. Finally, pheochromocytoma (PC12) cells were cultured on the NGCs to monitor their ability to extend neurites which is the base of a good nerve regeneration. In addition to remarkably improved cell adhesion and proliferation on the plasma-treated NGCs, an outstanding neural differentiation occurred. In fact, PC12 cells seeded on the treated samples extended numerous long neurites eventually establishing a neural network-like morphology with an overall neurite direction following the alignment of the underlying fibers. Overall, PCL/PLGA NGCs electrospun using the 2-pole air gap collector and O2 plasma-treated using an HCD reactor are promising candidates toward a full repair of critical nerve damage.

Novel IP2C sensors with flexible electrodes based on plasma-treated conductive elastomeric nanocomposites

Ionic polymer-metal composites (IPMC) are devices composed of metallic electrodes and an ionomeric polymer membrane in a ‘sandwich’ architecture and. Their main property is electromechanical actuation or sensing based on the movement of ions. Metallic electrodes are commonly used for their high electrical conductivity, malleability, and chemical resistance. However, the high cost of noble metals, such as platinum, long manufacturing time, and fatigue failure limit their application. Therefore, the replacement of metallic electrodes with conductive elastomeric nanocomposites (CENs) was evaluated to reduce the costs and complexity of manufacturing the device and increase its working life. In this work, carbon nanotubes were used as the conductive fillers. The dispersion to achieve high electrical conductivity was carried out directly in the synthetic or natural polyisoprene rubber latex assisted by surfactant and high-power sonication. To improve the adhesion between the elastomeric electrode and the ionic membrane (Nafion), plasma treatment with atmospheric air was applied as a surface modifier. This treatment improved the hydrophilicity and adhesion of the rubbers by forming oxygenated groups and increasing the surface nanoroughness. In this way, ionomeric polymer–polymer composite (IP2C) devices were fabricated using Nafion and plasma-modified CENs, this type of electrode is unprecedented in the literature for this application. These devices showed displacement and strain sensing capacity at levels close to the conventional IPMC in all tested frequency ranges and applied accelerations. Notably, the IP2C obtained better resolution at low frequencies than the control.

Surface nanoroughness impacts the formation and stability of supported lipid bilayers

Solid supported lipid bilayers (SLBs) are excellent platforms for studying the biophysical properties of cell membranes, as well as versatile biomimetic films for biotechnology applications. Among the existing approaches used to form SLBs, vesicle fusion and rupture onto solid supports is the most commonly employed one owing to its straightforward procedure. SLBs are typically formed on atomically flat and very hydrophilic surfaces, overlooking the influence of roughness and topography on membrane formation and organization. As a matter of fact, lipid bilayers in vivo are corrugated at the nanoscale level, as a result of interactions with proteins, fibrils, and other components within the intracellular and extracellular environment. Fundamental studies of the effect of surface roughness on SLBs are scarce and restricted to few contributions, where nanoroughness has shown to affect lipid mobility by a 5-fold decrease and inhibit domain growth in phase-separated membranes. In this work, the impact of nanoroughness on the formation and stability of SLBs onto SiO2 surfaces with different degrees of vertical and lateral surface roughness is studied. Combining quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy with force spectroscopy (AFM-FS), it is shown that nanoroughness affects the formation of SLBs by increasing the activation energy of vesicle fusion, rupture and spreading, and weakens the stability and lateral organization of the formed SLBs.

Biocompatible 3D-Printed Tendon/Ligament Scaffolds Based on Polylactic Acid/Graphite Nanoplatelet Composites.

Three-dimensional (3D) printing technology has become a popular tool to produce complex structures. It has great potential in the regenerative medicine field to produce customizable and reproducible scaffolds with high control of dimensions and porosity. This study was focused on the investigation of new biocompatible and biodegradable 3D-printed scaffolds with suitable mechanical properties to assist tendon and ligament regeneration. Polylactic acid (PLA) scaffolds were reinforced with 0.5 wt.% of functionalized graphite nanoplatelets decorated with silver nanoparticles ((f-EG)+Ag). The functionalization of graphene was carried out to strengthen the interface with the polymer. (f-EG)+Ag exhibited antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), an important feature for the healing process and prevention of bacterial infections. The scaffolds' structure, biodegradation, and mechanical properties were assessed to confirm their suitability for tendon and ligamentregeneration. All scaffolds exhibited surface nanoroughness created during printing, which was increased by the filler presence. The wet state dynamic mechanical analysis proved that the incorporation of reinforcement led to an increase in the storage modulus, compared with neat PLA. The cytotoxicity assays using L929 fibroblasts showed that the scaffolds were biocompatible. The PLA+[(f-EG)+Ag] scaffolds were also loaded with human tendon-derived cells and showed their capability to maintain the tenogenic commitment with an increase in the gene expression of specific tendon/ligament-related markers. The results demonstrate the potential application of these new 3D-printed nanocomposite scaffolds for tendon and ligament regeneration.

Co-Electrospun Poly(ε-Caprolactone)/Zein Articular Cartilage Scaffolds.

Osteoarthritis scaffold-based grafts fail because of poor integration with the surrounding soft tissue and inadequate tribological properties. To circumvent this, we propose electrospun poly(ε-caprolactone)/zein-based scaffolds owing to their biomimetic capabilities. The scaffold surfaces were characterized using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, static water contact angles, and profilometry. Scaffold biocompatibility properties were assessed by measuring protein adsorption (Bicinchoninic Acid Assay), cell spreading (stained F-actin), and metabolic activity (PrestoBlue™ Cell Viability Reagent) of primary bovine chondrocytes. The data show that zein surface segregation in the membranes not only completely changed the hydrophobic behavior of the materials, but also increased the cell yield and metabolic activity on the scaffolds. The surface segregation is verified by the infrared peak at 1658 cm-1, along with the presence and increase in N1 content in the survey XPS. This observation could explain the decrease in the water contact angles from 125° to approximately 60° in zein-comprised materials and the decrease in the protein adsorption of both bovine serum albumin and synovial fluid by half. Surface nano roughness in the PCL/zein samples additionally benefited the radial spreading of bovine chondrocytes. This study showed that co-electrospun PCL/zein scaffolds have promising surface and biocompatibility properties for use in articular-tissue-engineering applications.

Investigation of coated 316L steel surface: Surface morphology, composition, corrosion, and biocompatibility using hydroxyapatite mixed-EDM process

316L stainless steel belongs to insufficient biological responses and corrosion resistance. Although hydroxyapatite powder (HAp)-based coating improves biological responses and corrosion resistance of the 316L stainless steel, these coatings have resulted in inferior adhesion strength and cracked surface. This study aims to synthesize a highly biocompatible and corrosion resistant coating on the 316L stainless steel with a high adhesion strength and surface integrity using the electro discharge machining (EDM) method. The study also aims to explore the impacts of process parameters on the surface features. To reach the set objectives, several characterisation methods including atomic force microscopy (AFM), scanning electronic microscopy (SEM), X-ray powder diffraction (XRD), Potentiostat (electrochemical cell), MTT assay and X-ray photoelectron spectroscopy (XPS) were adopted. The HAp-mixed EDM method synthesized a biocompatible and corrosion resistant coating with an average thickness of 14.6 μm and 20.8 MPa adhesion strength comprising of Ca-P based oxides and carbides. The modified surface showed nano surface roughness of 18.5 nm. The oxides and carbides formed in the coating improved the cell viability of 316L stainless steel surface to 87 % and corrosion resistance to 0.00123 mm per year. This study is trying to gain the attention of 316L stainless steel-based bioimplant manufacturers to launch the hydroxyapatite mixed-EDM method for concurrent machining and coating.

Experimental Investigations of Nano Finishing Process on Nickel-Free Austenitic Stainless Steel by Grey Relational and Principal Component Analysis

The nano surface roughness of metallic materials is important in engineering and medical fields for specific applications. Magneto rheological abrasive flow finishing (MRAFF) process was performed on nickel-free austenitic stainless workpieces in order to obtain surface roughness at the nano level and also to forecast the performance of the MRAFF process in terms of responses such as surface roughness (SR) and material removal rate (MRR). These two responses are affected by process factors such as hydraulic pressure, current to the electromagnet, and the number of cycles performed during the machining process. The design of experiments (DOE) was used to determine the contributions of process parameters to output responses. The techniques of grey relational analysis (GRA) and principal component analysis (PCA) were used in these experimental investigations to discover the process factors that minimise the final Ra and maximise MRR. Through the DOE, a minimum SR of 63.24 nm and a maximum MRR of 2.34 mg/sec were obtained on the samples for the combination of 30 bar pressure, 6 A current, and 300 number of cycles.

Effect of drying conditions on adhesion strength of a pressure-sensitive adhesive

ABSTRACT Regular surface roughness could be created on the surface of a pressure-sensitive adhesive (PSA) film through Marangoni flow during the drying process. Therefore, tailoring of both surface and bulk characteristics of the PSA and consequently its adhesion strength could be expected by controlling the drying conditions. Herein, surface and bulk properties of a water-based PSA dried at various temperatures and humidities were scrutinized. Increase in the drying temperature improved the adhesion strength of the PSA to poly(ethylene terephthalate) due to enhanced surface nanoroughness of its film. At constant humidity, the higher the Péclet number, the higher the Marangoni number and the rougher the PSA film surface. Drying humidity rise, however, improved the adhesion strength due to more uniform distribution of copolymers constituting the PSA, better interdiffusion of chains through the interface of polymer particles in a prolonged drying process, and increased surface free energy of the film. The adhesion strength of the PSA, similar to the here-defined viscoelastic dissipation ability, demonstrated a power dependence on the film surface nanoroughness. This newly-defined parameter considers taking advantage of the real viscoelastic dissipation of the PSA regarding its potentiality through thorough wetting of the substrate surface with the PSA.

Nano-scale smooth surface of the compact-TiO2 layer via spray pyrolysis for controlling the grain size of the perovskite layer in perovskite solar cells.

The mechanism of perovskite film growth is critical for the final morphology and, thus, the performance of the perovskite solar cell. The nano-roughness of compact TiO2 (c-TiO2) fabricated via the spray pyrolysis method had a significant effect on the perovskite grain size and perovskite solar cell performance in this work. While spray pyrolysis is a low-cost and straightforward deposition technique suitable for large-scale application, it is influenced by a number of parameters, including (i) alcoholic solvent precursor, (ii) spray temperature, and (iii) annealing temperature. Among alcoholic solvents, 2-propanol and 1-butanol showed a smooth surface without any large TiO2 particles on the surface compared to EtOH. The lowest roughness of the c-TiO2 layer was obtained at 450 °C with an average perovskite grain size of around 300 nm. Increased annealing temperature has a positive effect on the roughness of TiO2. The highest efficiency of the solar cell was achieved by using 1-butanol as the solvent. The decrease in the nano roughness of c-TiO2 promoted larger perovskite grain sizes via a relative decrease in the nucleation rate. Therefore, controlling the spray pyrolysis technique used to deposit the c-TiO2 layer is a promising route to control the surface nanoroughness of c-TiO2, which results in an increase in the MAPbI3 grain size.

An effective laser surface treatment method to reduce biofilm coverage of multiple bacterial species associated with medical device infection

Device associated infection (DAI) is recognized as a worldwide health challenge in total joint replacement (TJR). Bacteria exhibit very strong antibiotic tolerance when they attach to a device and form a biofilm and thus DAI is difficult to treat. In this study, a one-step, clean (no chemicals or additional materials involved) and effective surface engineering approach via laser surface treatment (LST) to tackle the DAI challenge is reported. Commercially pure (CP) Ti were laser-treated in open air using continuous wave (CW) fibre laser. The laser-treated CP Ti was tested against five bacterial species including Gram positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram negative (Pseudomonas aeruginosa, Escherichia coli and Proteus mirabilis). Live/Dead staining and image analysis results indicated that LST can significantly reduce biofilm coverage of the five tested bacterial species on the CP Ti surfaces. Overall biofilm coverage as a percentage of the surface reduced after laser treatment averaging from 4.24 % to 17.4 %. This meant that relative to the untreated surface, biofilm coverage was reduced after laser treatment, ranging from 84.9 % to 95.6 % across the five species. Furthermore, cytotoxicity results (using MTT assay) showed that the laser-treated CP Ti is non-toxic across both L929 fibroblast and RAW macrophage cell lines. Surface properties after LST were investigated using WLI and AFM (measuring micro-/nano-surface roughness and topography) as well as ToF-SIMS (measuring surface chemistry and oxide thickness), respectively. The cross-sectional microstructure at the surface was imaged using SEM and analysed by XRD, whilst the surface wettability was measured using sessile drop method. To summarise, the reduction of biofilm coverage can be attributed to the favourable changes in surface roughness and topography together with the increased concentration of oxides at the topmost surface after LST.

Polyethylene Glycol-b-poly(trialkylsilyl methacrylate-co-methyl methacrylate) Hydrolyzable Block Copolymers for Eco-Friendly Self-Polishing Marine Coatings.

Hydrolyzable block copolymers consisting of a polyethylene glycol (PEG) first block and a random poly(trialkylsilyl methacrylate (TRSiMA, R = butyl, isopropyl)-co-methyl methacrylate (MMA)) second block were synthesized by RAFT polymerization. Two PEGs with different molar masses (Mn = 750 g/mol (PEG1) and 2200 g/mol (PEG2)) were used as macro-chain transfer agents and the polymerization conditions were set in order to obtain copolymers with a comparable mole content of trialkylsilyl methacrylate (~30 mole%) and two different PEG mole percentages of 10 and 30 mole%. The hydrolysis rates of PEG-b-(TRSiMA-co-MMA) in a THF/basic (pH = 10) water solution were shown to drastically depend on the nature of the trialkylsilyl groups and the mole content of the PEG block. Films of selected copolymers were also found to undergo hydrolysis in artificial seawater (ASW), with tunable erosion kinetics that were modulated by varying the copolymer design. Measurements of the advancing and receding contact angles of water as a function of the immersion time in the ASW confirmed the ability of the copolymer film surfaces to respond to the water environment as a result of two different mechanisms: (i) the hydrolysis of the silylester groups that prevailed in TBSiMA-based copolymers; and (ii) a major surface exposure of hydrophilic PEG chains that was predominant for TPSiMA-based copolymers. AFM analysis revealed that the surface nano-roughness increased upon immersion in ASW. The erosion of copolymer film surfaces resulted in a self-polishing, antifouling behavior against the diatom Navicula salinicola. The amount of settled diatoms depended on the hydrolysis rate of the copolymers.

How Streptococcus mutans Affects the Surface Topography and Electrochemical Behavior of Nanostructured Bulk Ti.

The metabolization of carbohydrates by Streptococcus mutans leads to the formation of lactic acid in the oral cavity, which can consequently accelerate the degradation of dental implants fabricated from commercially available microcrystalline Ti. Microstructure influences surface topography and hence interaction between bacteria cells and Ti surfaces. This work offers the first description of the effect of S. mutans on the surface topography and properties of nanostructured bulk Ti, which is a promising candidate for modern narrow dental implants owing to its superior mechanical strength. It was found that S. mutans incubation resulted in the slight, unexpected decrease of surface nanoroughness, which was previously developed owing to privileged oxidation in areas of closely spaced boundaries. However, despite the changes in nanoscale surface topography, bacteria incubation did not reduce the high level of protection afforded by the oxide layer formed on the nanostructured Ti surface. The results highlight the need–hitherto ignored–to consider Ti microstructure when analyzing its behavior in the presence of carbohydrate-metabolizing bacteria.

Modified Aerotaxy for the Plug-in Manufacture of Cell-Penetrating Fenton Nanoagents for Reinforcing Chemodynamic Cancer Therapy.

The assemblies of anisotropic nanomaterials have attracted considerable interest in advanced tumor therapeutics because of the extended surfaces for loading of active molecules and the extraordinary responses to external stimuli for combinatorial therapies. These nanomaterials were usually constructed through templated or seed-mediated hydrothermal reactions, but the lack of uniformity in size and morphology, as well as the process complexities from multiple separation and purification steps, impede their practical use in cancer nanotherapy. Gas-phase epitaxy, also called aerotaxy (AT), has been introduced as an innovative method for the continuous assembly of anisotropic nanomaterials with a uniform distribution. This process does not require expensive crystal substrates and high vacuum conditions. Nevertheless, AT has been used limitedly to build high-aspect-ratio semiconductor nanomaterials. With these considerations, a modified AT was designed for the continuous in-flight assembly of the cell-penetrating Fenton nanoagents (Mn-Fe CaCO3 (AT) and Mn-Fe SiO2 (AT)) in a single-pass gas flow because cellular internalization activity is essential for cancer nanotherapeutics. The modified AT of Mn-Fe CaCO3 and Mn-Fe SiO2 to generate surface nanoroughness significantly enhanced the cellular internalization capability because of the preferential contact mode with the cancer cell membrane for Fenton reaction-induced apoptosis. In addition, it was even workable for doxorubicin (DOX)-resistant cancer cells after DOX loading on the nanoagents. After combining with immune-checkpoint blockers (antiprogrammed death-ligand 1 antibodies), the antitumor effect was improved further with no systemic toxicity as chemo-immuno-chemodynamic combination therapeutics despite the absence of targeting ligands and external stimuli.

Moisture Damage of Asphalt Based on Adhesion, Microsurface Energy, and Nanosurface Roughness

Moisture Damage of Asphalt Based on Adhesion, Microsurface Energy, and Nanosurface Roughness

Designing suture-proof cell-attachable copolymer-mediated and curcumin- β-cyclodextrin inclusion complex loaded aliphatic polyester-based electrospun antibacterial constructs

The paper demonstrates curcumin/β-cyclodextrin-based inclusion complex (IC) loaded polyvinyl alcohol (PVA) dip-coated and copolymer-compatibilized polylactic acid (PLA)/poly(ε-caprolactone) (PCL) blend-based electrospun mats (EMs) as antibacterial, and suture-resistant constructs, to overcome the present challenges in developing structurally-stable, biocompatible, pliable, and stand-alone multifunctional-biomedical-devices. The thermal, microstructural, and viscoelastic characterization confirmed the presence of H-bonding interactions between IC and PVA moieties and between IC incorporated PVA matrix with the copolymer-mediated nanotextured PLA/PCL blend-based EMs. IC release and surface PVA erosion induced a decrease in modulus (>4-fold) and strength (>2-fold) of constructs (post-release). Mechanistically new and architectural-framework-defined PVA-gelation induced bi-axially diverted suture-failure (post-release) and resulted in a significant enhancement in suture-retention-strength (>3-fold), energy (>5-fold), and displacement (>2-fold) for ~20 wt% IC-loaded-PVA-coated EM-constructs. The fabricated EM-constructs exhibited improvement in surface-hydrophilicity (contact angle ~45°), surface nano-roughness (~ 600 nm), surface area (~34 m2/g), pore volume (~3.6 × 10−2 cc/g), IC release efficacy (~20 % burst release), antibacterial activity (adherent bacteria <10 %) against E. coli and S. aureus, and L929 fibroblast-cell-viability (~135 %), which varied as a function of IC-content in the PVA matrix. Our study conceptually establishes a novel and efficient technique for designing antibacterial, suture-resistant engineered-EM-constructs with tunable properties for their potential use in wound-dressings, periodontal-membranes, drug-delivery, and regenerative-systems.

Surface-Engineered Hybrid Gelatin Methacryloyl with Nanoceria as Reactive Oxygen Species Responsive Matrixes for Bone Therapeutics.

Designing various transplantable biomaterials, especially nanoscale matrixes for bone regeneration, involves precise tuning of topographical features. The cellular fate on such engineered surfaces is highly influenced by many factors imparted by the surface modification (hydrophilicity, stiffness, porosity, roughness, ROS responsiveness). Herein, hybrid matrixes of gelatin methacryloyl (GelMA) decorated with uniform layers of nanoceria (nCe), called Ce@GelMA, were developed without direct incorporation of nCe into the scaffolds. The fabrication involves a simple base-mediated in situ deposition in which uniform nCe coatings were first made on GelMA hydrogels and then nCe layered GelMA scaffolds were made by cryodesiccation. In this hybrid platform, degradable GelMA biopolymer provides the porous microstructure and nCe provides the nanoscaled biointerface. The surface morphology and elemental composition of the matrixes analyzed by field emission scanning electron microscopy (FE-SEM) and energy-dispersive spectroscopy (EDS) show uniform nCe distribution. The surface nanoroughness and chemistry of the matrixes were also characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The presence of nCe on GelMA enhanced its mechanical properties as confirmed by compressive modulus analysis. Substantial bonelike nanoscale hydroxyapatite formation was observed on scaffolds after simulated body fluid (SBF) immersion, which was confirmed by SEM, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. Moreover, the developed scaffolds could also be used as an antioxidant matrix owing to the reactive oxygen species (ROS) scavenging property of nCe as assessed by 3,3',5,5'-tetramethylbenzidine (TMB) assay. The enhanced proliferation and viability of rat bone marrow mesenchymal stem cells (rMSCs) on the scaffold surface after 3 days of culture ensures the biocompatibility of the proposed material. Considering all, it is proposed that the micro/nanoscaled matrix could mimic the composition and function of hard tissues and could be utilized as degradable scaffolds in engineering bones.