Nanofibrous scaffolds of ϵ-polycaprolactone containing Sr/Se-hydroxyapatite/graphene oxide for tissue engineering applications

Effects of mechanical properties of carbon-based nanocomposites on scaffolds for tissue engineering applications: a comprehensive review

Mechanical properties, such as elasticity modulus, tensile strength, elongation, hardness, density, creep, toughness, brittleness, durability, stiffness, creep rupture, corrosion and wear, a low coefficient of thermal expansion, and fatigue limit, are some of the most important features of a biomaterial in tissue engineering applications. Furthermore, the scaffolds used in tissue engineering must exhibit mechanical and biological behaviour close to the target tissue. Thus, a variety of materials has been studied for enhancing the mechanical performance of composites. Carbon-based nanostructures, such as graphene oxide (GO), reduced graphene oxide (rGO), carbon nanotubes (CNTs), fibrous carbon nanostructures, and nanodiamonds (NDs), have shown great potential for this purpose. This is owing to their biocompatibility, high chemical and physical stability, ease of functionalization, and numerous surface functional groups with the capability to form covalent bonds and electrostatic interactions with other components in the composite, thus significantly enhancing their mechanical properties. Considering the outstanding capabilities of carbon nanostructures in enhancing the mechanical properties of biocomposites and increasing their applicability in tissue engineering and the lack of comprehensive studies on their biosafety and role in increasing the mechanical behaviour of scaffolds, a comprehensive review on carbon nanostructures is provided in this study.

A comprehensive review on the applications of carbon-based nanostructures in wound healing: from antibacterial aspects to cell growth stimulation

A wound is defined as damage to the integrity of biological tissue, including skin, mucous membranes, and organ tissues. The treatment of these injuries is an important challenge for medical researchers. Various materials have been used for wound healing and dressing applications among which carbon nanomaterials have attracted significant attention due to their remarkable properties. In the present review, the latest studies on the application of carbon nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), carbon dots (CDs), carbon quantum dots (CQDs), carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds (NDs) in wound dressing applications are evaluated. Also, a variety of carbon-based nanocomposites with advantages such as biocompatibility, hemocompatibility, reduced wound healing time, antibacterial properties, cell-adhesion, enhanced mechanical properties, and enhanced permeability to oxygen has been reported for the treatment of various wounds.

Recent Development of Nano-Carbon Material in Pharmaceutical Application: A Review

Carbon nanomaterials have attracted researchers in pharmaceutical applications due to their outstanding properties and flexible dimensional structures. Carbon nanomaterials (CNMs) have electrical properties, high thermal surface area, and high cellular internalization, making them suitable for drug and gene delivery, antioxidants, bioimaging, biosensing, and tissue engineering applications. There are various types of carbon nanomaterials including graphene, carbon nanotubes, fullerenes, nanodiamond, quantum dots and many more that have interesting applications in the future. The functionalization of the carbon nanomaterial surface could modify its chemical and physical properties, as well as improve drug loading capacity, biocompatibility, suppress immune response and have the ability to direct drug delivery to the targeted site. Carbon nanomaterials could also be fabricated into composites with proteins and drugs to reduce toxicity and increase effectiveness in the pharmaceutical field. Thus, carbon nanomaterials are very effective for applications in pharmaceutical or biomedical systems. This review will demonstrate the extraordinary properties of nanocarbon materials that can be used in pharmaceutical applications.

Antibacterial and in vivo toxicological studies of Bi2O3/CuO/GO nanocomposite synthesized via cost effective methods

In this research work, Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO nanocomposites have been synthesized via an eco-friendly green synthesis technique, solgel route and co-precipitation method respectively for the assessment of antibacterial activity as well as in vivo toxicity. The XRD patterns confirm the formation of Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO nanocomposites showing monoclinic structures. Crystallite size and lattice strain are calculated by Scherrer equation, Scherrer plot and Willimson Hall plot methods. Average crystallite size measured for Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO nanocomposites by Scherrer equation, Scherrer plot and WH-plot methods are (5.1, 13.9, 11.5)nm, (5.4, 14.2, 11.3)nm and (5.2, 13.5, 12.0)nm respectively. Optical properties such as absorption peaks and band-gap energies are studied by UV–vis spectroscopy. The FTIR peaks at 513 cm⁻¹, 553 cm⁻¹ and 855 cm⁻¹ confirms the successful synthesis of Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO nanocomposites. The antibacterial activity of synthesized Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO nanocomposites is examined against two gram-negative (Escherichia coli and pseudomonas) as well as gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) at dose 25 mg/kg and 40 mg/kg by disk diffusion technique. Zone of inhibition for Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO at dose 40 mg/kg against E. coli (gram − ve) are 12 mm, 17 mm and 18 mm respectively and against Pseudomonas (gram − ve) are 28 mm, 19 mm and 21 mm respectively. While the zone of inhibition for Bi₂O₃/GO and Bi₂O₃/CuO/GO at dose 40 mg/kg against B. cereus (gram + ve) are 8 mm and 8.5 mm respectively and against S. aureus (gram + ve) are 5 mm and 10.5 mm respectively. These amazing results reveal that Bi₂O₃, Bi₂O₃/GO and Bi₂O₃/CuO/GO nanocomposite as a kind of antibacterial content, have enormous potential for biomedical applications. In addition, the in vivo toxicity of synthesized Bi₂O₃/CuO/GO nanocomposite is investigated on Swiss Albino mice at dose of 20 mg/kg by evaluating immune response, hematology and biochemistry at the time period of 2, 7, 14 and 30 days. No severe damage is observed in mice during whole treatment. The p value calculated by statistical analysis of hematological and biochemistry tests is nonsignificant which ensures that synthesized nanocomposites are safe and non-toxic as they do not affect mice significantly. This study proves that Bi₂O₃/CuO/GO nanocomposites are biocompatible and can be explored further for different biomedical applications.

In Vivo Bone Tissue Engineering Strategies: Advances and Prospects

Reconstruction of critical-sized bone defects remains a tremendous challenge for surgeons worldwide. Despite the variety of surgical techniques, current clinical strategies for bone defect repair demonstrate significant limitations and drawbacks, including donor-site morbidity, poor anatomical match, insufficient bone volume, bone graft resorption, and rejection. Bone tissue engineering (BTE) has emerged as a novel approach to guided bone tissue regeneration. BTE focuses on in vitro manipulations with seed cells, growth factors and bioactive scaffolds using bioreactors. The successful clinical translation of BTE requires overcoming a number of significant challenges. Currently, insufficient vascularization is the critical limitation for viability of the bone tissue-engineered construct. Furthermore, efficacy and safety of the scaffolds cell-seeding and exogenous growth factors administration are still controversial. The in vivo bioreactor principle (IVB) is an exceptionally promising concept for the in vivo bone tissue regeneration in a predictable patient-specific manner. This concept is based on the self-regenerative capacity of the human body, and combines flap prefabrication and axial vascularization strategies. Multiple experimental studies on in vivo BTE strategies presented in this review demonstrate the efficacy of this approach. Routine clinical application of the in vivo bioreactor principle is the future direction of BTE; however, it requires further investigation for overcoming some significant limitations.

Antibacterial Activity and Mechanism of GO/Cu2O/ZnO Coating on Ultrafine Glass Fiber

A GO (graphene oxide)/ZnO/Cu₂O antibacterial coating was successfully sprayed on the ultrafine glass fibers using room temperature hydrothermal synthesis and air spraying techniques. The microstructures of the antibacterial coating were characterized, and the results showed that the Cu₂ONPs (nano particles)/ZnONPs were uniformly dispersed on the surface of GO. Then, the antibacterial properties of the GO/ZnO/Cu₂O (GZC) antibacterial coating were evaluated using the disc diffusion test. It was found that the coating exhibits excellent antibacterial properties and stability against E. coli and S. aureus, and the antibacterial rate of each group of antibacterial powder against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was 100%. To explore the antibacterial mechanism of the GZC antibacterial powder on the ultrafine glass fibers based on the photocatalysis/oxidative stress method, the photoelectric coupling synergistic effect between GZC antibacterial coating was analyzed deeply. The results all showed that the photochemical activity of GZC antibacterial powder was significantly improved compared with pure component materials. The enhancement of its photochemical activity is beneficial to the generation of ROS (including hydroxyl radicals, superoxide anion radicals, etc.), which further confirms the speculation of the photocatalytic/oxidative stress mechanism.

Curcumin and Graphene Oxide Incorporated into Alginate Hydrogels as Versatile Devices for the Local Treatment of Squamous Cell Carcinoma

With the aim of preparing hybrid hydrogels suitable for use as patches for the local treatment of squamous cell carcinoma (SCC)-affected areas, curcumin (CUR) was loaded onto graphene oxide (GO) nanosheets, which were then blended into an alginate hydrogel that was crosslinked by means of calcium ions. The homogeneous incorporation of GO within the polymer network, which was confirmed through morphological investigations, improved the stability of the hybrid system compared to blank hydrogels. The weight loss in the 100–170 °C temperature range was reduced from 30% to 20%, and the degradation of alginate chains shifted to higher temperatures. Moreover, GO enhanced the stability in water media by counteracting the de-crosslinking process of the polymer network. Cell viability assays showed that the loading of CUR (2.5% and 5% by weight) was able to reduce the intrinsic toxicity of GO towards healthy cells, while higher amounts were ineffective due to the antioxidant/prooxidant paradox. Interestingly, the CUR-loaded systems were found to possess a strong cytotoxic effect in SCC cancer cells, and the sustained CUR release (~50% after 96 h) allowed long-term anticancer efficiency to be hypothesized.

Polycaprolactone-based antibacterial nanofibrous containing vanadium/hydroxyapatite with morphology, mechanical properties, and in vitro studies

Repairing the damaged wound tissues is a vital demand to keep an adequate clinical care system. In this work, nanofibrous scaffolds of polycaprolactone (PCL) have been encapsulated with hydroxyapatite (HAP)...

Toward nanotechnology-enabled face masks against SARS-CoV-2 and pandemic respiratory diseases

Wearing a face mask has become a necessity following the outbreak of the coronavirus (COVID-19) disease, where its effectiveness in containing the pandemic has been confirmed. Nevertheless, the pandemic has revealed major deficiencies in the ability to manufacture and ramp up worldwide production of efficient surgical-grade face masks. As a result, many researchers have focused their efforts on the development of low cost, smart and effective face covers. In this article, following a short introduction concerning face mask requirements, the different nanotechnology-enabled techniques for achieving better protection against the SARS-CoV-2 virus are reviewed, including the development of nanoporous and nanofibrous membranes in addition to triboelectric nanogenerators based masks, which can filter the virus using various mechanisms such as straining, electrostatic attraction and electrocution. The development of nanomaterials-based mask coatings to achieve virus repellent and sterilizing capabilities, including antiviral, hydrophobic and photothermal features are also discussed. Finally, the usability of nanotechnology-enabled face masks is discussed and compared with that of current commercial-grade N95 masks. To conclude, we highlight the challenges associated with the quick transfer of nanomaterials-enabled face masks and provide an overall outlook of the importance of nanotechnology in counteracting the COVID-19 and future pandemics.

Biomedical Applications of Carbon Nanomaterials: Fullerenes, Quantum Dots, Nanotubes, Nanofibers, and Graphene

Carbon nanomaterials (CNMs) have received tremendous interest in the area of nanotechnology due to their unique properties and flexible dimensional structure. CNMs have excellent electrical, thermal, and optical properties that make them promising materials for drug delivery, bioimaging, biosensing, and tissue engineering applications. Currently, there are many types of CNMs, such as quantum dots, nanotubes, nanosheets, and nanoribbons; and there are many others in development that promise exciting applications in the future. The surface functionalization of CNMs modifies their chemical and physical properties, which enhances their drug loading/release capacity, their ability to target drug delivery to specific sites, and their dispersibility and suitability in biological systems. Thus, CNMs have been effectively used in different biomedical systems. This review explores the unique physical, chemical, and biological properties that allow CNMs to improve on the state of the art materials currently used in different biomedical applications. The discussion also embraces the emerging biomedical applications of CNMs, including targeted drug delivery, medical implants, tissue engineering, wound healing, biosensing, bioimaging, vaccination, and photodynamic therapy.

Nanofibrous ε-polycaprolactone scaffolds containing Ag-doped magnetite nanoparticles: Physicochemical characterization and biological testing for wound dressing applications in vitro and in vivo

Skin wounds can lead to numerous complications with dangerous health consequences. In this work, magnetite nanoparticles were doped with different concentrations of antimicrobial silver (Ag) ions and incorporated into the electrospun nanofibrous ε-polycaprolactone (PCL) scaffolds. Nanoparticles and scaffolds with various Ag contents were characterized using a range of physicochemical techniques. Ag entered magnetite as cations and preferentially positioned at tetrahedral sites, introducing lattice distortions and topographic irregularities. Amorphization of the structure due to accommodation of Ag expanded the lattice in the bulk and contracted it on the surface, where broadened distribution of Fe–O coordinations was detected. Promoting spin canting and diminishing the double exchange interaction through altered distribution of ferric and ferrous ions, Ag softened the magnetism of magnetite. By making the nanoparticle structure more defective, Ag modified the interface with the polymer and promoted the protrusion of the nanoparticles from the surface of the polymeric nanofibers, thus increasing their roughness and hydrophilicity, with positive repercussions on cell adhesion and growth. Both the viability of human melanocytes and the antibacterial activity against E. coli and S. aureus increased with the concentration of Ag in the magnetite phase of the scaffolds. Skin wound healing rate in rats also increased in direct proportion with the concentration of Ag in the magnetite phase, and no abnormalities in the dermal and epidermal tissues were visible on day 10 in the treatment group. These results imply an excellent potential of these composite nanofibrous scaffolds for use as wound dressings and in other reconstructive skin therapies.

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Electrospun nanofibrous polymeric wound dressings interspersed with magnetite nanoparticles doped with Ag ions were fabricated.

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Detailed physicochemical characterization is provided with aid of diffractometric, spectroscopic and microscopic techniques.

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Both the viability of melanocytes and the antibacterial activity increased with the addition of Ag ions.

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Skin wound healing rate in rats increased to 51 and 92 % on day 10 for dressings without and with Ag, respectively, relative to control.

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Animals treated with Ag-doped dressings displayed no atrophy of sebaceous glands and necrosis of hair follicles of control animals.

Polycaprolactone based electrospun matrices loaded with Ag/hydroxyapatite as wound dressings: Morphology, cell adhesion, and antibacterial activity

The development of a scaffold matrix that can inhibit bacterial infection and promote wound healing simultaneously is an essential demand to improve the health care system. Hydroxyapatite (HAP) doped with different concentrations of silver ions (Ag⁺) were incorporated into electrospun nanofibrous scaffolds of polycaprolactone (PCL) using the electrospinning technique. The formed phase was identified using XRD, while the morphological and roughness behavior were investigated using FESEM. It was shown that scaffolds were configured in randomly distributed nanofibers with diameters around of 0.19-0.40, 0.31-0.54, 1.36, 0.122-0.429 μm for 0.0Ag-HAP@PCL, 0.2Ag-HAP@PCL, 0.6Ag-HAP@PCL, and 0.8Ag-HAP@PCL, respectively. Moreover, the maximum roughness peak height increased significantly from 179 to 284 nm, with the lowest and highest contributions of Ag. The mechanical properties were examined and displayed that the tensile strength increased from 3.11 ± 0.21 MPa to its highest value at 3.57 ± 0.31 MPa for 0.4Ag-HAP@PCL. On the other hand, the cell viability also was enhanced with the addition of Ag and improved from 97.1 ± 4.6% to be around 102.3 ± 3.1% at the highest contribution of Ag. The antibacterial activity was determined, and the highest imbibition zones were achieved at the highest Ag dopant to be 12.5 ± 1.1 mm and 11.4 ± 1.5 mm against E. coli and S. aureus. The in vitro cell proliferation was observed through human fibroblasts cell lone (HFB4) and illustrated that cells were able to grow and spread not only on the fibers' surface but also, they were spreading and adhered through the deep pores.

Protecting healthcare workers during COVID-19 pandemic with nanotechnology: A protocol for a new device from Egypt

The outbreak of the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is thought to have occurred first in Wuhan, China in December 2019, before spreading to over 120 countries in the months that followed. It was declared a “public health emergency of international concern” by the World Health Organization on January 31, 2020 and recognized as a pandemic on March 11, 2020. The primary route of SARS-CoV-2 transmission from human to human is through inhalation of respiratory droplets. Devising protective technologies for stopping the spread of the droplets of aerosol containing the viral particles is a vital requirement to curb the ongoing outbreak. However, the current generations of protective respirator masks in use are noted for their imperfect design and there is a need to develop their more advanced analogues, with higher blockage efficiency and the ability to deactivate the trapped bacteria and viruses. It is likely that one such design will be inspired by nanotechnologies. Here we describe a new design from Egypt, utilizing a reusable, recyclable, customizable, antimicrobial and antiviral respirator facial mask feasible for mass production. The novel design is based on the filtration system composed of a nanofibrous matrix of polylactic acid and cellulose acetate containing copper oxide nanoparticles and graphene oxide nanosheets and produced using the electrospinning technique. Simultaneously, the flat pattern fabricated from a thermoplastic composite material is used to provide a solid fit with the facial anatomy. This design illustrates an effort made in a developing setting to provide innovative solutions for combating the SARS-CoV-2 pandemic of potentially global significance.

Physical, electrochemical and biological evaluations of spin-coated ε-polycaprolactone thin films containing alumina/graphene/carbonated hydroxyapatite/titania for tissue engineering applications

Composite structures are at the frontier of materials science and engineering and polymeric/ceramic composites present one of their most prospective subsets. Prior studies have shown both improvements and deteriorations of properties of polymers upon the addition of ceramic phases to them, but not many studies have dealt with the direct comparison of chemically distinct inorganic additives. The goal of this study was to compare the properties of ε-polycaprolactone (PCL) thin films supplemented with alumina, graphene, carbonated hydroxyapatite or titania particles, individually, in identical amounts (12 wt%). The composite films were analyzed for their phase composition, grain size, morphology, surface roughness, porosity, cell response, mechanical properties and electrochemical performance. Each additive imparted one or more physical or biological properties onto PCL better than others. Thus, alumina increased the microhardness of the films better than any other additive, with the resulting values exceeding 10 MPa. It also led to the formation of a composite with the least porosity and the greatest stability to degradation in simulated body fluid based on open circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). Titania made the surface of PCL roughest, which in combination with its high porosity explained why it was the most conducive to the growth of human fibroblasts, alongside being most prone to degradation in wet, corrosive environments and having the highest Poisson's ratio. Graphene, in contrast, made the surface of PCL smoothest and the bulk structure most porous, but also most conductive, with the OCP of -37 mV. The OCP of PCL supplemented with carbonated hydroxyapatite had the highest OCP of -134 mV and also the highest mechanical moduli, including the longitudinal (781 MPa), the shear (106 MPa), the bulk (639 MPa), and the elastic (300 MPa). The only benefit of the deposition of multilayered PCL films supplemented with all four inorganic additives was to enable a relatively high resistance to degradation. This study demonstrates that the properties of thin PCL films could be effectively optimized through the simple choice of appropriate inorganic additives dispersed in them. There is no single additive that proves ideal for improving all the properties of interest in PCL thin films, but their choice should be adjusted to the actual application. One such method of compositional optimization could prove crucial in the effort to develop biocomposites for superior performance in tissue engineering applications.

Augmented healing of full thickness chronic excision wound by rosmarinic acid loaded chitosan encapsulated graphene nanopockets

Nanoparticles have emerged as an important carrier system to treat wounds as they permit the topical administration of an antimicrobial drug in a sustained and effective manner. On the other hand, if active excipients are added during the formulation, such as chitosan or graphene oxide, the developed Nano formulation could significantly improve its potential for chronic wound healing. Given that, we have conceived the fabrication and evaluation of rosmarinic acid loaded chitosan encapsulated graphene nanoparticles (RA-CH-G-NPOs) formulation to enhance wound healing capacity. The prepared nanoparticles were characterized by particle size, Zeta potential, FT-IR, SEM, TEM and AFM. It was observed the average diameter of RA-CH-G-NPOS is around 417.5 ± 18.3 nm and showed sustained release behavior. Optimized RA-CH-G-NPOs were incorporated into Carbopol gel and evaluated for drug content, pH, in vitro release, texture analysis, and viscosity. The antibacterial activity of optimized formulation was examined as a minimum inhibitory concentration against Staphylococcus aureus. The fabricated RA-CH-G-NPOs were than evaluated for in vitro antimicrobial activity by microdilution assay The combination of RA, Chitosan and Graphene oxide (GO) showed higher antibacterial activity of 0.0038 ± 0.2 mg/mL. Further, these nanoparticles were evaluated in- vivo for wound healing efficacy in Sprague Dawley rats. Histopathological evaluations demonstrated that RA-CH-G-NPOs showed significantly enhanced wound contraction, enhanced cell adhesion, epithelial migration, and high hydroxyproline content leading to faster and more efficient collagen synthesis as compared to plain carbopol, plain RA and controls. Hence the topical administration of fabricated RA-CH-G-NPOs appears to be an interesting and suitable strategy for the treatment of chronic wounds.

Blend biopolymeric nanofibrous scaffolds of cellulose acetate/ε-polycaprolactone containing metallic nanoparticles prepared by laser ablation for wound disinfection applications

Laser ablation technique was utilized to synthesize versatile metallic nanoparticles including ZnO, Ag and CuO which were incorporated into the blend matrix of cellulose Acetate (CA) and ε-polycaprolactone (PCL) nanofibrous scaffold. The compositional, microstructural and morphological behaviors for the obtained nanofibers were investigated using X-ray diffraction (XRD), Fourier Transformed Infrared, Transmission Electron Microscope (TEM) and Field Emission-Scanning Electron Microscope (FESEM). The cell viability and antibacterial activity were investigated against Staphylococcus aureus (S. aureus) and Escherichia coli (E-coli). TEM micrographs refer that while CuONPs were involved in the middle of CA/PCL fibrous scaffold with diameters around 160 nm. The morphological investigations indicated the scaffolds were configured in a non-oriented form with diameters 0.45-0.9 μm in the case of ZnONPs involved in blend matrix fibers. The ratio of viable cells displays that compositions are biocompatible, while the antibacterial activity of both AgNPs and CuONPs showed an inhibition zone around 11.2.3 ± 2.2 mm and 9.4 ± 1.2 mm respectively. Bio-blend polymers matrices carrying nanoparticles could be tailored for a plethora of biomedical applications upon their compositions.