Controlled Liposome Delivery from Chitosan-Based Thermosensitive Hydrogel for Regenerative Medicine

This work describes the development of an injectable nanocomposite system based on a chitosan thermosensitive hydrogel combined with liposomes for regenerative medicine applications. Liposomes with good physicochemical properties are prepared and embedded within the chitosan network. The resulting nanocomposite hydrogel is able to provide a controlled release of the content from liposomes, which are able to interact with cells and be internalized. The cellular uptake is enhanced by the presence of a chitosan coating, and cells incubated with liposomes embedded within thermosensitive hydrogels displayed a higher cell uptake compared to cells incubated with liposomes alone. Furthermore, the gelation temperature of the system resulted to be equal to 32.6 °C; thus, the system can be easily injected in the target site to form a hydrogel at physiological temperature. Given the peculiar performance of the selected systems, the resulting thermosensitive hydrogels are a versatile platform and display potential applications as controlled delivery systems of liposomes for tissue regeneration.

Preparation of mesoporous silica-based nanocomposites with synergistically antibacterial performance from nano-metal (oxide) and polydopamine

In this work, a novel antibacterial nanocomposite system was developed using mesoporous silica (MSN) as an effective nanocarrier, and the resultant nanocomposites demonstrated remarkable antibacterial performance due to the synergistic effect among nano zinc oxides, silver nanoparticles, and polydopamine (PDA). The successful synthesis of MSN/ZnO@PDA/Ag nanocomposites was confirmed. The physicochemical properties and the morphologies of these nanocomposites were investigated. It was found that the particle size increased along with the evolution of these nanocomposites. Besides, nano zinc oxides were formed in the nanoconfinement channel of mesoporous silica with a particle size about 2 nm, and that of silver nanoparticle was less than 50 nm. In addition, the results revealed that the presence of mesoporous silica could effectively prevent the formation of large-size silver nanoparticles and facilitate their well dispersion. Due to the synergistic effect among nano zinc oxides, silver nanoparticles, and polydopamine, these nanocomposites exhibited remarkable antibacterial performance even at a low concentration of 313 ppm, and the antibacterial mechanism was also elucidated. Therefore, this work provides a facile and controllable approach to preparing synergistically antibacterial nanocomposites, and the remarkable antibacterial performance make them suitable for practical applications.

Ternary Nanocomposite System Composing of Graphene Nanoplatelet, Cellulose Nanofiber and Jatropha Oil Based Waterborne Polyurethane: Characterizations, Mechanical, Thermal Properties and Conductivity

This work aims to evaluate the performance of graphene nanoplatelet (GNP) as conductive filler with the presence of 0.5 wt.% cellulose nanofiber (CNF) on the physical, mechanical, conductivity and thermal properties of jatropha oil based waterborne polyurethane. Polyurethane was made from crude jatropha oil using an epoxidation and ring-opening process. 0.5, 1.0, 1.5, 2.0 wt.% GNP and 0.5 wt.% CNF were incorporated using casting method to enhance film performance. Mechanical properties were studied following standard method as stated in ASTM D638-03 Type V. Thermal stability of the nanocomposite system was studied using thermal gravimetric analysis (TGA). Filler interaction and chemical crosslinking was monitored using Fourier-transform infrared spectroscopy (FTIR) and film morphology were observed with field emission scanning electron microscopy (FESEM). Water uptake analysis, water contact angle and conductivity tests are also carried out. The results showed that when the GNP was incorporated at fixed CNF content, it was found to enhance the nanocomposite film, its mechanical, thermal and water behavior properties as supported by morphology and water uptake. Nanocomposite film with 0.5 wt.% GNP shows the highest improvement in term of tensile strength, Young’s modulus, thermal degradation and water behavior. As the GNP loading increases, water uptake of the nanocomposite film was found relatively small (<1%). Contact angle test also indicates that the film is hydrophobic with addition of GNP. The conductivity properties of the nanocomposite film were not enhanced due to electrostatic repulsion force between GNP sheet and hard segment of WBPU. Overall, with addition of GNP, mechanical and thermal properties was greatly enhanced. However, conductivity value was not enhanced as expected due to electrostatic repulsion force. Therefore, ternary nanocomposite system is a suitable candidate for coating application.

Functionalized Organic–Inorganic Liposome Nanocomposites for the Effective Photo-Thermal Therapy of Breast Cancer

Organic–inorganic nanocomposites for photothermal therapy of cancers emerged as a promising strategy against malignant tumors. However, it is still a big challenge to develop a nanocomposite system that can maximize the synergistic photo-thermal therapy effect as well as preserve high stability for simultaneous delivery of the chemotherapeutic drugs and photo-thermal agents. Here, we have exploited an organic liposome containing inorganic core for co-loading the aggregates of bovine serum albumin (BSA), indocyanine green (ICG), and doxorubicin (DOX), abbreviated as BID-liposomal nanocomposites. The three kinds of substances were aggregated in the core of liposomal nanocomposites through hydrophobic and electrostatic interactions. In vitro characterization shows that BID-liposomal nanocomposites were spherical nanoparticles with size of 30–50 nm and good storage stability. Moreover, BID-Liposomal nanocomposites illustrate the strongest cytotoxicity among all the formulations against murine 4T1 tumor cells. In breast cancer-bearing mouse models, BID liposomes lead to significant improvements in tumor inhibition effects with no obvious toxicity. Therefore, the BID-liposomal nanoparticle is believed to be a promising strategy for chemo-photo-thermal therapy against cancers.

Gold-Nanoparticle-Deposited TiO2 Nanorod/Poly(Vinylidene Fluoride) Composites with Enhanced Dielectric Performance

Flexible dielectric polymer composites have been of great interest as embedded capacitor materials in the electronic industry. However, a polymer composite has a low relative dielectric permittivity (ε′ < 100), while its dielectric loss tangent is generally large (tanδ > 0.1). In this study, we fabricate a novel, high-permittivity polymer nanocomposite system with a low tanδ. The nanocomposite system comprises poly(vinylidene fluoride) (PVDF) co-filled with Au nanoparticles and semiconducting TiO2 nanorods (TNRs) that contain Ti3+ ions. To homogeneously disperse the conductive Au phase, the TNR surface was decorated with Au-NPs ~10–20 nm in size (Au-TNRs) using a modified Turkevich method. The polar β-PVDF phase was enhanced by the incorporation of the Au nanoparticles, partially contributing to the enhanced ε′ value. The introduction of the Au-TNRs in the PVDF matrix provided three-phase Au-TNR/PVDF nanocomposites with excellent dielectric properties (i.e., high ε′ ≈ 157 and low tanδ ≈ 0.05 at 1.8 vol% of Au and 47.4 vol% of TNRs). The ε′ of the three-phase Au-TNR/PVDF composite is ~2.4-times higher than that of the two-phase TNR/PVDF composite, clearly highlighting the primary contribution of the Au nanoparticles at similar filler loadings. The volume fraction dependence of ε′ is in close agreement with the effective medium percolation theory model. The significant enhancement in ε′ was primarily caused by interfacial polarization at the PVDF–conducting Au nanoparticle and PVDF–semiconducting TNR interfaces, as well as by the induced β-PVDF phase. A low tanδ was achieved due to the inhibited conducting pathway formed by direct Au nanoparticle contact.

Biosynthesis of silver nanoparticles for the fabrication of non cytotoxic and antibacterial metallic polymer based nanocomposite system

Nanomaterials have significantly contributed in the field of nanomedicine as this subject matter has combined the usefulness of natural macromolecules with organic and inorganic nanomaterials. In this respect, various types of nanocomposites are increasingly being explored in order to discover an effective approach in controlling high morbidity and mortality rate that had triggered by the evolution and emergence of multidrug resistant microorganisms. Current research is focused towards the production of biogenic silver nanoparticles for the fabrication of antimicrobial metallic-polymer-based non-cytotoxic nanocomposite system. An ecofriendly approach was adapted for the production of silver nanoparticles using fungal biomass (Aspergillus fumigatus KIBGE-IB33). The biologically synthesized nanoparticles were further layered with a biodegradable macromolecule (chitosan) to improve and augment the properties of the developed nanocomposite system. Both nanostructures were characterized using different spectrographic analyses including UV–visible and scanning electron microscopy, energy dispersive X-ray analysis, dynamic light scattering, and Fourier transform infrared spectroscopic technique. The biologically mediated approach adapted in this study resulted in the formation of highly dispersed silver nanoparticles that exhibited an average nano size and zeta potential value of 05 nm (77.0%) and − 22.1 mV, respectively with a polydispersity index of 0.4. Correspondingly, fabricated silver–chitosan nanocomposites revealed a size of 941 nm with a zeta potential and polydispersity index of + 63.2 mV and 0.57, respectively. The successful capping of chitosan on silver nanoparticles prevented the agglomeration of nanomaterial and also facilitated the stabilization of the nano system. Both nanoscopic entities exhibited antimicrobial potential against some pathogenic bacterial species but did not displayed any antifungal activity. The lowest minimal inhibitory concentration of nanocomposite system (1.56 µg ml−1) was noticed against Enterococcus faecalis ATCC 29212. Fractional inhibitory concentration index of the developed nanocomposite system confirmed its improved synergistic behavior against various bacterial species with no cytotoxic effect on NIH/3T3 cell lines. Both nanostructures, developed in the present study, could be utilized in the form of nanomedicines or nanocarrier system after some quantifiable trials as both of them are nonhazardous and have substantial antibacterial properties.

A magnetically retrievable mixed-valent Fe3O4@SiO2/Pd0/PdII nanocomposite exhibiting facile tandem Suzuki coupling/transfer hydrogenation reaction

Herein, we report a magnetically retrievable mixed-valent Fe3O4@SiO2/Pd0/PdIINP (5) nanocomposite system for tandem Suzuki coupling/transfer hydrogenation reaction. The nanocomposite 5 was prepared first by making a layer of $$\hbox {SiO}_{2}$$ SiO 2 on $$\hbox {Fe}_{3}\hbox {O}_{4}\hbox {NP}$$ Fe 3 O 4 NP followed by deposition of $$\hbox {Pd}^{0}$$ Pd 0 and sorption of $$\hbox {Pd}^{\mathrm{II}}$$ Pd II ions successively onto the surface of Fe3O4@SiO2NP. The nanocomposite was characterized by powder XRD, electron microscopy (SEM-EDS and TEM-EDS) and XPS spectroscopy techniques. The mixed-valent $$\hbox {Pd}^{0}/\hbox {Pd}^{\mathrm{II}}$$ Pd 0 / Pd II present onto the surface of nanocomposite 5 was confirmed by XPS technique. Interestingly, the mixed-valent nanocomposite Fe3O4@SiO2/Pd0/PdIINP (5) exhibited tandem Suzuki coupling/transfer hydrogenation reaction during the reaction of aryl bromide with aryl boronic acid (90% of C). The nanocomposite 5 displayed much better reactivity as compared to the monovalent Fe3O4@SiO2/Pd0NP (3) (25% of C) and Fe3O4@SiO2/PdIINP (4) (15% of C) nanocomposites. Further, because of the presence of magnetic $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 , the nanocomposite displayed its facile separation from the reaction mixture and reused at least for five catalytic cycles.

Chitosan/Silver Nanoparticle/Graphene Oxide Nanocomposites with Multi-drug Release, Antimicrobial, and Photothermal Conversion Functions

In this work, we designed and fabricated a multifunctional nanocomposite system which consists of chitosan, raspberry-like silver nanoparticles and graphene oxide. Room temperature atmospheric pressure microplasma (RT-APM) process provides a rapid, facile, and environment-friendly method for introducing silver nanoparticles into the composite system. By loading different drugs onto the polymer matrix and/or graphene oxide, our composite can achieve a pH controlled dual drug release with release profile specific to the drugs used. In addition to its strong antibacterial ability against E. coli and S. aureus, our composite also demonstrates excellent photothermal conversion effect under irradiation of near infrared lasers. These unique functionalities point to it&rsquo;s the potential of nanocomposite system in multiple applications areas such as multimodal therapeutics in healthcare, water treatment, and anti-microbial, etc.