Tissue engineered periosteum: Fabrication of a gelatin basedtrilayer composite scaffold with biomimetic properties for enhanced bone healing.

The periosteum, a vascularized tissue membrane, is essential in bone regeneration following fractures and bone loss due to some other reasons, yet there exist several research gaps concerning its regeneration. These gaps encompass reduced cellular proliferation and bioactivity, potential toxicity, heightened stiffness of scaffold materials, unfavorable porosity, expensive materials and procedures, and suboptimal survivability or inappropriate degradation rates of the implanted materials. This research used an interdisciplinary approach by forming a new material fabricated through electrospinning for the proposed application as a layer-by-layer tissue-engineered periosteum (TEP). TEP comprises poly(ε-caprolactone) (PCL), PCL/gelatin/magnesium-doped zinc oxide (vascular layer), and gelatin/bioactive glass/COD liver oil (osteoconductive layer). These materials were selected for their diverse properties, when integrated into the scaffold formation, successfully mimic the characteristics of native periosteum. Scanning electron microscopy (SEM) was employed to confirm the trilayer structure of the scaffold and determine the average fiber diameter. In-vitro degradation and swelling studies demonstrated a uniform degradation rate that matches the typical recovery time of periosteum. The scaffold exhibited excellent mechanical properties comparable to natural periosteum. Furthermore, the sustained release kinetics of COD liver oil were observed in the trilayer scaffold. Cell culture results indicated that the three-dimensional topography of the scaffold promoted cell growth, proliferation, and attachment, confirming its non-toxicity, biocompatibility, and bioactivity. This study suggests that the fabricated scaffold holds promise as a potential artificial periosteum for treating periostitis and bone fractures.

2-Dimensional Ti3C2Tx/NaF nano-composites as electrode materials for hybrid battery-supercapacitor applications.

The increasing global demand for energy storage solutions has spurred interest in advanced materials for electrochemical energy storage devices. Transition-metal carbides and nitrides, known as MXenes, are characterized by remarkable conductivity and tunable properties, They have gained significant attention for their potential in energy storage applications. The properties of two-dimensional (2-D) MXenes can be tuned by doping or composite formation. We report a novel Ti3C2Tx/NaF composite prepared via a straightforward hydrothermal process for supercapacitor electrode applications. Three composites with varying NaF concentrations (1%, 3%, and 5%) were synthesized under similar conditions. Structural characterization using X-ray diffraction (XRD) and scanning electron microscopy confirmed the successful formation of the composites, whereas distinct shifts in XRD peaks and new peaks revealed the presence of NaF. Electrochemical performance was evaluated by cyclic voltammetry, galvanostatic charging-discharging, and electrochemical impedance spectroscopy. The composites exhibited pseudo-capacitive behavior with reversible redox reactions during charge and discharge cycles. Specific capacitance of 191 F/g at scan rates of 2 mV/s was measured in 1 M KOH. Electrochemical impedance spectroscopy revealed an escalating impedance factor as NaF content increases within Ti3C2Tx. This study underscores the versatile energy storage potential of Ti3C2Tx/NaF composites, offering insights into their tailored properties and behavior.

Intercalation of C60 into MXene Multilayers: A Promising Approach for Enhancing the Electrochemical Properties of Electrode Materials for High-Performance Energy Storage Applications.

In this study, we report on the enhancement of the electrochemical properties of MXene by intercalating C60 nanoparticles between its layers. The aim was to increase the interlayer spacing of MXene, which has a direct effect on capacitance by allowing the electrolyte flow in the electrode. To achieve this, various concentrations of Ti3SiC2 (known as MXene) and C60 nanocomposites were prepared through a hydrothermal process under optimal conditions. The resulting composites were characterized by using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, Raman spectroscopy, and cyclic voltammetry. Electrodes were fabricated using different concentrations of MXene and C60 nanocomposites, and current-voltage (I-V) measurements were performed at various scan rates to analyze the capacitance of pseudo supercapacitors. The results showed the highest capacitance of 348 F g1- for the nanocomposite with a composition of 90% MXene and 10% C60. We introduce MXene-C60 composites as promising electrode materials for supercapacitors and highlight their unique properties. Our work provides a new approach to designing high-performance electrode materials for supercapacitors, which can have significant implications for the development of efficient energy storage systems.

Enhancing supercapacitor performance through design optimization of laser-induced graphene and MWCNT coatings for flexible and portable energy storage.

The field of supercapacitors consistently focuses on research and challenges to improve energy efficiency, capacitance, flexibility, and stability. Low-cost laser-induced graphene (LIG) offers a promising alternative to commercially available graphene for next-generation wearable and portable devices, thanks to its remarkable specific surface area, excellent mechanical flexibility, and exceptional electrical properties. We report on the development of LIG-based flexible supercapacitors with optimized geometries, which demonstrate high capacitance and energy density while maintaining flexibility and stability. Three-dimensional porous graphene films were synthesized, and devices with optimized parameters were fabricated and tested. One type of device utilized LIG, while two other types were fabricated on LIG by coating multi-walled carbon nanotubes (MWCNT) at varying concentrations. Characterization techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Raman spectroscopy, and voltammetry, were employed to analyze the fabricated devices. AFM analysis revealed a surface roughness of 2.03 µm for LIG due to laser treatment. SEM images displayed compact, dense, and porous surface morphology. XRD analysis confirmed the presence of graphene and graphene oxide, which was further supported by energy-dispersive X-ray spectroscopy (EDX) data. Raman spectroscopy indicated that the fabricated samples exhibited distinct D and G bands at 1362 cm-1 and 1579 cm-1, respectively. Cyclic voltammetry (CV) results showed that LIG's capacitance, power density, and energy density were 6.09 mF cm-2, 0.199 mW cm-2, and 3.38 µWh cm-2, respectively, at a current density of 0.2 mA cm-2. The LIG-MWCNT coated electrode exhibited a higher energy density of 6.05 µWh cm-2 and an areal-specific capacitance of 51.975 mF cm-2 compared to the LIG-based devices. The fabricated device has potential applications in smart electronics, nanorobotics, microelectromechanical systems (MEMS), and wearable and portable electronics.

Defects mediated weak ferromagnetism in Zn1-yCyO (0.00 ≤ y ≤ 0.10) nanorods semiconductors for spintronics applications.

A series of carbon-doped ZnO [Zn1-yCyO (0.00 ≤ y ≤ 0.10)] nanorods were synthesized using a cost-effective low-temperature (85 °C) dip coating technique. X-ray diffractometer scans of the samples revealed the hexagonal structure of the C-doped ZnO samples, except for y = 0.10. XRD analysis confirmed a decrease in the unit cell volume after doping C into the ZnO matrix, likely due to the incorporation of carbon at oxygen sites (CO defects) resulting from ionic size differences. The morphological analysis confirmed the presence of hexagonal-shaped nanorods. X-ray photoelectron spectroscopy identified C-Zn-C bonding, i.e., CO defects, Zn-O-C bond formation, O-C-O bonding, oxygen vacancies, and sp2-bonded carbon in the C-doped ZnO structure with different compositions. We analyzed the deconvoluted PL visible broadband emission through fitted Gaussian peaks to estimate various defects for electron transition within the bandgap. Raman spectroscopy confirmed the vibrational modes of each constituent. We observed a stronger room-temperature ferromagnetic nature in the y = 0.02 composition with a magnetization of 0.0018 emu/cc, corresponding to the highest CO defects concentration and the lowest measured bandgap (3.00 eV) compared to other samples. Partial density of states analysis demonstrated that magnetism from carbon is dominant due to its p-orbitals. We anticipate that if carbon substitutes oxygen sites in the ZnO structure, the C-2p orbitals become localized and create two holes at each site, leading to enhanced p-p type interactions and strong spin interactions between carbon atoms and carriers. This phenomenon can stabilize the long-range order of room-temperature ferromagnetism properties for spintronic applications.

Smart and pH-sensitive rGO/Arabinoxylan/chitosan composite for wound dressing: In-vitro drug delivery, antibacterial activity, and biological activities.

Carbohydrate polymers are biological macromolecules that have sparked a lot of interest in wound healing due to their outstanding antibacterial properties and sustained drug release. Arabinoxylan (ARX), Chitosan (CS), and reduced graphene oxide (rGO) sheets were combined and crosslinked using tetraethyl orthosilicate (TEOS) as a crosslinker to fabricate composite hydrogels and assess their potential in wound dressing for skin wound healing. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and biological assays were used to evaluate the composite hydrogels. FTIR validated the effective fabrication of the composite hydrogels. The rough morphologies of the composite hydrogels were revealed by SEM and AFM (as evident from the Ra values). ATC-4 was discovered to have the roughest surface. TEM revealed strong homogeneous anchoring of the rGO to the polymer matrix. However, with higher amount of rGO agglomeration was detected. The % swelling at various pHs (1-13) revealed that the hydrogels were pH-sensitive. The controlled release profile for the antibacterial drug (Silver sulfadiazine) evaluated at various pH values (4.5, 6.8, and 7.4) in PBS solution and 37 °C using the Franz diffusion method revealed maximal drug release at pH 7.4 and 37 °C. The antibacterial efficacy of the composite hydrogels against pathogens that cause serious skin diseases varied. The MC3T3-E1 cell adhered, proliferated, and differentiated well on the composite hydrogels. MC3T3-E1 cell also illustrated excellent viability (91%) and proper cylindrical morphologies on the composite hydrogels. Hence, the composite hydrogels based on ARX, CS, and rGO are promising biomaterials for treating and caring for skin wounds.

Synthesis and Characterization of Silver-Coated Polymeric Scaffolds for Bone Tissue Engineering: Antibacterial and In Vitro Evaluation of Cytotoxicity and Biocompatibility.

In bone tissue engineering, multifunctional composite materials are very challenging. Bone tissue engineering is an innovative technique to develop biocompatible scaffolds with suitable orthopedic applications with enhanced antibacterial and mechanical properties. This research introduces a polymeric nanocomposite scaffold based on arabinoxylan-co-acrylic acid, nano-hydroxyapatite (nHAp), nano-aluminum oxide (nAl2O3), and graphene oxide (GO) by free-radical polymerization for the development of porous scaffolds using the freeze-drying technique. These polymeric nanocomposite scaffolds were coated with silver (Ag) nanoparticles to improve antibacterial activities. Together, nHAp, nAl2O3, and GO enhance the multifunctional properties of materials, which regulate their physicochemical and biomechanical properties. Results revealed that the Ag-coated polymeric nanocomposite scaffolds had excellent antibacterial properties and better microstructural properties. Regulated morphological properties and maximal antibacterial inhibition zones were found in the porous scaffolds with the increasing amount of GO. Moreover, the nanosystem and the polymeric matrix have improved the compressive strength (18.89 MPa) and Young's modulus (198.61 MPa) of scaffolds upon increasing the amount of GO. The biological activities of the scaffolds were investigated against the mouse preosteoblast cell lines (MC3T3-E1) and increasing the quantities of GO helps cell adherence and proliferation. Therefore, our findings showed that these silver-coated polymeric nanocomposite scaffolds have the potential for engineering bone tissue.

Arabinoxylan/graphene-oxide/nHAp-NPs/PVA bionano composite scaffolds for fractured bone healing.

The importance of bone scaffolds has increased many folds in the last few years; however, during bone implantation, bacterial infections compromise the implantation and tissue regeneration. This work is focused on this issue while not compromising on the properties of a scaffold for bone regeneration. Biocomposite scaffolds (BS) were fabricated via the freeze-drying technique. The samples were characterized for structural changes, surface morphology, porosity, and mechanical properties through spectroscopic (Fourier transform-infrared [FT-IR]), microscopic (scanning electron microscope [SEM]), X-ray (powder X-ray diffraction and energy-dispersive X-ray), and other analytical (Brunauer-Emmett-Teller, universal testing machine Instron) techniques. Antibacterial, cellular, and hemocompatibility assays were performed using standard protocols. FT-IR confirmed the interactions of all the components. SEM illustrated porous and interconnected porous morphology. The percentage porosity was in the range of 49.75%-67.28%, and the pore size was 215.65-470.87 µm. The pore size was perfect for cellular penetration. Thus, cells showed significant proliferation onto these scaffolds. X-ray studies confirmed the presence of nanohydroxyapatite and graphene oxide (GO). The cell viability was 85%-98% (BS1-BS3), which shows no significant toxicity of the biocomposite. Furthermore, the biocomposites exhibited better antibacterial activity, no effect on the blood clotting (normal in vitro blood clotting), and less than 5% hemolysis. The ultimate compression strength for the biocomposites increased from 4.05 to 7.94 with an increase in the GO content. These exciting results revealed that this material has the potential for possible application in bone tissue engineering.

Correction: Development and in vitro evaluation of κ-carrageenan based polymeric hybrid nanocomposite scaffolds for bone tissue engineering.

[This corrects the article DOI: 10.1039/D0RA07446B.].

Novel functional antimicrobial and biocompatible arabinoxylan/guar gum hydrogel for skin wound dressing applications.

It is a challenging task to develop active biomacromolecular wound dressing materials that are biocompatible and possesses antibacterial properties against the bacterial strains that cause severe skin disease. This work is focused on the preparation of a biocompatible and degradable hydrogel for wound dressing application using arabinoxylan (ARX) and guar gum (GG) natural polymers. Fourier transform infrared spectroscopy (FT-IR) confirmed that both ARX and GG interacted well with each other, and their interactions further increased with the addition of crosslinker tetraethyl orthosilicate. Scanning electron microscope (SEM) micrographs showed uniform porous morphologies of the hydrogels. The porous morphologies and uniform interconnected pores are attributed to the increased crosslinking of the hydrogel. Elastic modulus, tensile strength, and fracture strain of the hydrogels significantly improved (from ATG-1 to ATG-4) with crosslinking. Degradability tests showed that hydrogels lost maximum weight in 7 days. All the samples showed variation in swelling with pH. Maximum swelling was observed at pH 7. The hydrogel samples showed good antibacterial activity against Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive) in PBS, good drug release profile (92% drug release), and nontoxic cellular behavior. The cells not only retained their cylindrical morphologies onto the hydrogel but were also performing their normal activities. It is, therefore, believed that as-developed hydrogel could be a potential material for wound dressing application.

Arabinoxylan-co-AA/HAp/TiO2 nanocomposite scaffold a potential material for bone tissue engineering: An in vitro study.

Arabinoxylan (AX) is a natural biological macromolecule with several potential biomedical applications. In this research, AX, nano-hydroxyapatite (n-HAp) and titanium dioxide (TiO2) based polymeric nanocomposite scaffolds were fabricated by the freeze-drying method. The physicochemical characterizations of these polymeric nanocomposite scaffolds were performed for surface morphology, porosity, swelling, biodegradability, mechanical, and biological properties. The scaffolds exhibited good porosity and rough surface morphology, which were efficiently controlled by TiO2 concentrations. MC3T3-E1 cells were employed to conduct the biocompatibility of these scaffolds. Scaffolds showed unique biocompatibility in vitro and was favorable for cell attachment and growth. PNS3 proved more biocompatible, showed interconnected porosity and substantial mechanical strength compared to PNS1, PNS2 and PNS4. Furthermore, it has also showed more affinity to cells and cell growth. The results illustrated that the bioactive nanocomposite scaffold has the potential to find applications in the tissue engineering field.

Development and in vitro evaluation of κ-carrageenan based polymeric hybrid nanocomposite scaffolds for bone tissue engineering.

The excellent biocompatible and osteogenesis characteristics of porous scaffolds play a vital role in bone regeneration. In this study, we have synthesized polymeric hybrid nanocomposites via free-radical polymerization from carrageenan/acrylic-acid/graphene/hydroxyapatite. Porous hybrid nanocomposite scaffolds were fabricated through a freeze-drying method to mimic the structural and chemical composition of natural bone. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and water contact-angle studies were carried-out for functional groups, surface morphology and hydrophilicity of the materials, followed by biodegradation and swelling analysis. The cell viability, cell culture and proliferation were evaluated against mouse pre-osteoblast (MC3T3-E1) cell lines using neutral red dye assay. The cell adherence and proliferation studies were determined by SEM. Physical characterization including optimum porosity and pore size (49.75% and 0.41 × 103 µm2), mechanical properties (compression strength 8.87 MPa and elastic modulus 442.63 MPa), swelling (70.20% at 27 °C and 77.21% at 37 °C) and biodegradation (23.8%) were performed. The results indicated CG-g-AAc-3 with a high optical density and better cell viability. Hence, CG-g-AAc-3 was found to be more efficient for bone regeneration with potential applications in fractured bone regeneration.

Doxorubicin-loaded photosensitive magnetic liposomes for multi-modal cancer therapy.

Multifunctional magnetic nanosystems have attracted an enormous attention of researchers for their potential applications in cancer diagnostics and therapy. The localized nanotherapies triggered by the external stimuli, like magnetic fields and visible light, are significant in clinical applications. We report a liposomal system that aims to treat cancer by magnetic hyperthermia, photodynamic therapy and chemotherapy simultaneously. The liposomes enclose clinically used photosensitizer m-THPC (Foscan) and anti-cancer drug doxorubicin, in its hydrophobic lipid bilayers, and contains magnetite nanoparticles in hydrophilic core. Three different sizes of magnetic nanoparticles (10, 22 and 30nm) and liposomes (40, 70 and 110nm) were used in this study. Magnetite single domain nanoparticles forming the magnetic core were superparamagnetic but liposomes expressed slight coercivity and hysteresis due to the clustering of nanoparticles in the core. This enhanced the heating efficiency (specific power loss) of the liposomes under an AC field (375kHz, 170Oe). Cell viability and toxicity were studied on HeLa cells using MTT assay and proteomic analysis. Confocal and fluorescence microscopy were used to study the photosensitizer's profile and cells response to combined therapy. It revealed that combined therapy almost completely eliminated the cancer cells as opposed to the separate treatments. Magnetic hyperthermia and photodynamic therapies were almost equally effective whereas chemotherapy showed the least effect.

Mixed Brownian alignment and Néel rotations in superparamagnetic iron oxide nanoparticle suspensions driven by an ac field.

Superparamagnetic iron oxide nanoparticles with highly nonlinear magnetic behavior are attractive for biomedical applications like magnetic particle imaging and magnetic fluid hyperthermia. Such particles display interesting magnetic properties in alternating magnetic fields and here we document experiments that show differences between the magnetization dynamics of certain particles in frozen and melted states. This effect goes beyond the small temperature difference (ΔT ~ 20 °C) and we show the dynamics to be a mixture of Brownian alignment of the particles and Néel rotation of their moments occurring in liquid particle suspensions. These phenomena can be modeled in a stochastic differential equation approach by postulating log-normal distributions and partial Brownian alignment of an effective anisotropy axis. We emphasize that precise particle-specific characterization through experiments and nonlinear simulations is necessary to predict dynamics in solution and optimize their behavior for emerging biomedical applications including magnetic particle imaging.

Slew-rate dependence of tracer magnetization response in magnetic particle imaging.

Magnetic Particle Imaging (MPI) is a new biomedical imaging technique that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide nanoparticle tracers. Currently, 25 kHz and 20 mT/µ0 excitation fields are common in MPI, but lower field amplitudes may be necessary for patient safety in future designs. Here, we address fundamental questions about MPI tracer magnetization dynamics and predict tracer performance in future scanners that employ new combinations of excitation field amplitude (Ho ) and frequency (ω). Using an optimized, monodisperse MPI tracer, we studied how several combinations of drive field frequencies and amplitudes affect the tracer's response, using Magnetic Particle Spectrometry and AC hysteresis, for drive field conditions at 15.5, 26, and 40.2 kHz, with field amplitudes ranging from 7 to 52 mT/µ0. For both fluid and immobilized nanoparticle samples, we determined that magnetic response was dominated by Néel reversal. Furthermore, we observed that the peak slew-rate (ωHo) determined the tracer magnetic response. Smaller amplitudes provided correspondingly smaller field of view, sometimes resulting in excitation of minor hysteresis loops. Changing the drive field conditions but keeping the peak slew-rate constant kept the tracer response almost the same. Higher peak slew-rates led to reduced maximum signal intensity and greater coercivity in the tracer response. Our experimental results were in reasonable agreement with Stoner-Wohlfarth model based theories.