The electrospinning process was used successfully to fabricate nanofibers of poly(ethylene oxide) (PEO) in which multiwalled carbon nanotubes (MWCNT) are embedded. Initial dispersion of MWCNTs in water was achieved using amphiphiles, either as small molecules (sodium dodecyl sulfate, SDS) or as a high molecular weight, highly branched polymer (Gum Arabic). These dispersions provided separation of the MWCNTs and their individual incorporation into the PEO nanofibers by subsequent electrospinning. The focus of this work is on the development of axial orientations in these multicomponent nanofibers. A theoretical model is presented for the behavior of rodlike particles representing CNTs in electrospinning. Initially the rods are randomly oriented, but due to the sinklike flow in a wedge they are gradually oriented mainly along the stream lines, so that straight CNTs are almost oriented upon entering the electrospun jet. The degrees of orientation of polymer, surfactant, and MWCNT were studied using X-ray dif...

Carbon Nanotubes Embedded in Oriented Polymer Nanofibers by Electrospinning

The electrical properties of polymer nanocomposites containing a small amount of carbon
nanotube (CNT) are remarkably superior to those of conventional electronic composites. Based on three-dimensional (3D) statistical percolation and 3D resistor network modeling, the electrical properties of CNT nanocomposites, at and after percolation, were successfully predicted in this work. The numerical analysis was also extended to investigate the effects of the aspect ratio, the electrical conductivity, the aggregation and the shape of CNTs on the electrical properties of the nanocomposites. A simple empirical model was also established based on present numerical simulations to predict the electrical conductivity in several electronic composites with various fillers. This investigation further highlighted the importance
of theoretical and numerical analyses in the exploration of basic physical phenomena, such as percolation and conductivity in novel nanocomposites.

The electrical properties of polymer nanocomposites with carbon nanotube fillers

Noble metal nanoparticles due to their unique optical properties arising from their interactions with an incident light have been intensively employed in a broad range of applications. This review comprehensively describes fundamentals behind plasmonics, used to develop applications in the fields of biomedical, energy, and information technologies. Basic concepts (electromagnetic interaction and permittivity of metals) are discussed through Mie theory presented as the main model for interpreting phenomena of optical absorption and scattering. The effects of near-field enhancement, shape, composition, and surrounding medium of nanoparticles on optical properties are described in detail. The review explores and identifies the potential of plasmonic nanoparticles based on their optical properties (e.g., light absorption, scattering, and field enhancement) for developing different applications (biomedical, energy and information technologies). Due to a significant impact of plasmonic nanoparticles on medicine and healthcare products and technologies, the review initially focuses on biomedical applications extensively benefited from optical features of these nanoparticles. Advantages of the optical properties outstandingly implemented are also briefly discussed in other applications, including energy and information technologies. This review concisely summarizes the explored areas based on plasmonic properties, compares advantages of plasmonic nanoparticles over other types of nanomaterials and highlights challenges.

Optical Properties and Applications of Plasmonic-Metal Nanoparticles

Traditional treatment approaches for cancer involve intravenous chemotherapy or other forms of drug delivery. These therapeutic measures suffer from several limitations such as nonspecific targeting, poor biodistribution, and buildup of drug resistances. However, significant technological advancements have been made in terms of superior modes of drug delivery over the last few decades. Technical capability in analyzing the molecular mechanisms of tumor biology, nanotechnology─particularly the development of biocompatible nanoparticles, surface modification techniques, microelectronics, and material sciences─has increased. As a result, a significant number of nanostructured carriers that can deliver drugs to specific cancerous sites with high efficiency have been developed. This particular maneuver that enables the introduction of a therapeutic nanostructured substance in the body by controlling the rate, time, and place is defined as the nanostructured drug delivery system (NDDS). Because of their versatility and ability to incorporate features such as specific targeting, water solubility, stability, biocompatibility, degradability, and ability to reverse drug resistance, they have attracted the interest of the scientific community, in general, and nanotechnologists as well as biomedical scientists. To keep pace with the rapid advancement of nanotechnology, specific technical aspects of the recent NDDSs and their prospects need to be reported coherently. To address these ongoing issues, this review article provides an overview of different NDDSs such as lipids, polymers, and inorganic nanoparticles. In addition, this review also reports the challenges of current NDDSs and points out the prospective research directions of these nanocarriers. From our focused review, we conclude that still now the most advanced and potent field of application for NDDSs is lipid-based, while other significantly potential fields include polymer-based and inorganic NDDSs. However, despite the promises, challenges remain in practical implementations of such NDDSs in terms of dosage and stability, and caution should be exercised regarding biocompatibility of materials. Considering these aspects objectively, this review on NDDSs will be particularly of interest for small-to-large scale industrial researchers and academicians with expertise in drug delivery, cancer research, and nanotechnology.

Recent Progress in Nanostructured Smart Drug Delivery Systems for Cancer Therapy: A Review.

Electrochemical sensor for nitrite detection in water samples using flexible laser-induced graphene electrodes functionalized by CNT decorated by Au nanoparticles

Review of hybrid PLGA nanoparticles: Future of smart drug delivery and theranostics medicine

The goal of this chapter is to provide a general introduction about graphene nanocomposites studied by Raman spectroscopy. The chapter will therefore begin with a brief description of the major Raman bands of carbon allotropes. In the following chapter a concise comparison between single walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), fullerenes and graphene is exposed. The characteristic features in Raman spectra of carbon allotropes, namely the intense signals D and G are investigated. In particular, the chapter will outline the Raman spectrum of graphene and different types of graphene oxide. The last part of the chapter is devoted to graphene nanocomposites.

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Graphene Nanocomposites Studied by Raman Spectroscopy

The current research study deals with the design and investigation of novel bioinspired and biocompatible GO-COOH decorated hybrid polymeric scaffolds with nanofibrous architecture as biomaterials with highly appropriate features for functional restoration of damaged tissue. Gelatin and alginate, two biobased-polymers with excellent biocompatibility, high microenvironment biomimicry and ability for proper guidance of cell development in combination with carboxylated graphene oxide (GO-COOH), embody the matrix of electrospun hybrid scaffolds. The underlying principle is based on various types of interactions that can take place between the functionalities of the system's entities (proved by DLS) and their synergy in improving the structural integrity, mechanical tailorability and biological performances of the new nanofibrous GO-COOH decorated hybrid scaffolds. The nanofibrous structure along with the presence of GO-COOH are established by SEM. The new covalent bonds formed between various functionalities of the protein-polysaccharide-GO-COOH system are proved by FTIR and XPS. The physico-chemical state of GO-COOH lattices within the hybrid structures is investigated by Raman spectrometry. The interpenetrated network of bicomponent structures determines a 10-fold increase of Young's modulus as compared to monocomponent counterparts while the dispersion of GO-COOH significantly increases the elasticity of materials. The biological results (MTT and LDH assays) indicate a good cytocompatibility of crosslinked bicomponent AGS scaffolds; the metabolic cellular activity is substantially improved following the GO-COOH addition, suggesting that GO-COOH can support the cell adhesion, growth and proliferation.

/pdf/design-of-new-bioinspired-go-cooh-decorated-alginate-gelatin-4t007r3mes.pdf

Design of new bioinspired GO-COOH decorated alginate/gelatin hybrid scaffolds with nanofibrous architecture: structural, mechanical and biological investigations

This research study reports the development of chitosan/carboxylated graphene oxide (CS/GO-COOH) composite scaffolds with nanofibrous architecture using the electrospinning method. The concept of designed composite fibrous material is based on bringing together the biological properties of CS, mechanical, electrical, and biological characteristics of GO-COOH with the versatility and efficiency of ultra-modern electrospinning techniques. Three different concentrations of GO-COOH were added into a chitosan (CS)-poly(ethylene oxide) (PEO) solution (the ratio between CS/PEO was 3/7 (w/w)) and were used in the synthesis process of composite scaffolds. The effect of GO-COOH concentration on the spinnability, morphological and mechanical features, wettability, and biological properties of engineered fibrous scaffolds was thoroughly investigated. FTIR results revealed the non-covalent and covalent interactions that could take place between the system’s components. The SEM micrographs highlighted the nanofibrous architecture of scaffolds, and the presence of GO-COOH sheets along the composite CS/GO-COOH nanofibers. The size distribution graphs showed a decreasing trend in the mean diameter of composite nanofibers with the increase in GO-COOH content, from 141.40 nm for CS/PG 0.1% to 119.88 nm for CS/PG 0.5%. The dispersion of GO-COOH led to composite scaffolds with increased elasticity; the Young’s modulus of CS/PG 0.5% (84 ± 4.71 MPa) was 7.5-fold lower as compared to CS/PEO (662 ± 15.18 MPa, p < 0.0001). Contact angle measurements showed that both GO-COOH content and crosslinking step influenced the surface wettability of scaffolds, leading to materials with ~1.25-fold higher hydrophobicity. The in vitro cytocompatibility assessment showed that the designed nanofibrous scaffolds showed a reasonable cellular proliferation level after 72 h of contact with the fibroblast cells.

Synthesis and Characterization of Electrospun Composite Scaffolds Based on Chitosan-Carboxylated Graphene Oxide with Potential Biomedical Applications.

The field of tissue engineering is constantly evolving as it aims to develop bioengineered and functional tissues and organs for repair or replacement. Due to their large surface area and ability to interact with proteins and peptides, graphene oxides offer valuable physiochemical and biological features for biomedical applications and have been successfully employed for optimizing scaffold architectures for a wide range of organs, from the skin to cardiac tissue. This review critically focuses on opportunities to employ protein–graphene oxide structures either as nanocomposites or as biocomplexes and highlights the effects of carbonaceous nanostructures on protein conformation and structural stability for applications in tissue engineering and regenerative medicine. Herein, recent applications and the biological activity of nanocomposite bioconjugates are analyzed with respect to cell viability and proliferation, along with the ability of these constructs to sustain the formation of new and functional tissue. Novel strategies and approaches based on stem cell therapy, as well as the involvement of the extracellular matrix in the design of smart nanoplatforms, are discussed.

/pdf/graphene-oxide-protein-based-scaffolds-for-tissue-30fmwj68.pdf

Elena Iuliana Bîru

Papers

Review of hybrid PLGA nanoparticles: Future of smart drug delivery and theranostics medicine

Graphene Nanocomposites Studied by Raman Spectroscopy

Design of new bioinspired GO-COOH decorated alginate/gelatin hybrid scaffolds with nanofibrous architecture: structural, mechanical and biological investigations

Synthesis and Characterization of Electrospun Composite Scaffolds Based on Chitosan-Carboxylated Graphene Oxide with Potential Biomedical Applications.

Graphene Oxide–Protein-Based Scaffolds for Tissue Engineering: Recent Advances and Applications