Vaginal Drug Delivery Systems to Control Microbe-Associated Infections

The vagina has been regarded as a crucial route for drug delivery. Despite the wide range of available vaginal dosage forms for vaginal infection control, poor drug absorptivity remains a significant challenge due to various biological barriers in the vagina, such as mucus, epithelium, immune systems, and others. To overcome these barriers, different types of vaginal drug delivery systems (VDDSs), with outstanding mucoadhesive, mucus-penetrating properties, have been designed to enhance the absorptivity of vagina-administered agents in the past decades. In this Review, we introduce a general understanding of vaginal administration, its biological barriers, the commonly used VDDSs, such as nanoparticles and hydrogels, and their applications in controlling microbe-associated vaginal infections. Additionally, further challenges and concerns regarding the design of VDDSs will be discussed.

Interfacial Engineering with Rigid Nanoplatelets in Immiscible Polymer Blends: Interface Strengthening and Interfacial Curvature Controlling

The interfacial nanoparticle compatibilization (INC) strategy has opened up a promising avenue toward simultaneous functionalization and interfacial engineering of immiscible polymer blends. While the INC mechanism has been well developed recently, few investigations have focused on rigid nanoplatelets because of the inherent steric hindrance of the surface-grafted polymer chains. Herein, surface-modified rigid nanoplatelets have been incorporated into an immiscible poly(l-lactide) (PLLA)/poly(butylene succinate) (PBSU) blend. It is demonstrated that the strong interfacial adhesion between PLLA and PBSU phases is promoted via molecular entanglements of the grafted chains on the surface of nanoplatelets with the individual components. A refined phase morphology with improved mechanical properties can be achieved with the addition of 5 wt % modified Gibbsite nanoplatelets. It was further found that the stiffness of nanoplatelets can change the geometry of the interface significantly. It is, therefore, indicated that the simultaneous interface strengthening and interfacial curvature controlling of rigid nanoplatelets originate from the selective swelling/collapse of the in situ-formed PLLA and PBSU grafts within the corresponding phase at the interface. Such a mechanism is confirmed by the Monte Carlo simulations. This work provides new opportunities for the fabrication of advanced polymer blend nanocomposites.

Photocurable acrylate epoxy/ZnO–Ag nanocomposite coating: fabrication, mechanical and antibacterial properties

In this study, a UV-curable acrylate epoxy nanocomposite coating has been prepared by incorporation of ZnO–Ag hybrid nanoparticles. For this purpose, firstly ZnO–Ag hybrid nanoparticles were fabricated by a seed-mediated growth method. Then, these ZnO–Ag hybrid nanoparticles (2 wt%) were added into the UV-curable acrylate resin matrices. The photocuring process of nanocomposite was evaluated by various factors, such as the conversion of acrylate double bonds, pendulum hardness and gel fraction. Under the 4.8 s UV-exposure time for full crosslinking, the obtained data indicated that incorporation of ZnO–Ag nanohybrids into the coating matrix changed the crosslinking process of coating significantly. A mechanical teat indicated that the presence of nanohybrids in photocurable coating matrix enhanced its abrasion resistance from 98.7 to 131.6 L per mil (33.3%). The antibacterial test against E. coli over 7 h indicated that E. coli bacteria were killed totally by nanocomposite coating, whereas it was 2.6 × 10⁴ CFU mL⁻¹ for the neat coating without nanoparticles.

ZnO-Ag hybrid nanoparticles were fabricated by seed-mediated growth method and incorporated into the UV-curable acrylate resin matrice to form a composite. This improved the mechanical property of UV-cured coating and exhibited high antibacterial activity against E. coli.

Ag Nanoparticle-Incorporated Natural Rubber for Mechanical Energy Harvesting Application

The energy conversion performance of the triboelectric nanogenerator (TENG) is a function of triboelectric charges which depend on the intrinsic properties of materials to hold charges or the dielectric properties of triboelectric materials. In this work, Ag nanoparticles were synthesized and used to incorporate into natural rubber (NR) in order to enhance the dielectric constant for enhancing the electrical output of TENG. It was found that the size of Ag nanoparticles was reduced with the increasing CTAB concentration. Furthermore, the CTAB surfactant helped the dispersion of metallic Ag nanoparticles in the NR-insulating matrix, which promoted interfacial polarization that affected the dielectric properties of the NR composite. Ag nanoparticle-incorporated NR films exhibited an improved dielectric constant of up to almost 40% and an enhanced TENG performance that generated the highest power density of 262.4 mW/m².

An Approach Towards Optimization Appraisal of Thermal Conductivity of Magnetic Thermoplastic Elastomeric Nanocomposites Using Response Surface Methodology

This study investigates the optimization of thermal conductivity of nickel zinc ferrite incorporated thermoplastic natural rubber nanocomposites using response surface methodology (RSM). The experimental runs were based on face-centered central composite design (FCCD) where three levels were designated for both temperature and magnetic filler content. The analysis of variance (ANOVA) results showed that the implemented technique is significant with an F-value of 35.7 and a p-value of <0.0001. Moreover, the statistical inference drawn from the quadratic model suggests a saddle response behavior the thermal conductivity took when both factors were correlated. The factors’ optimal set confined within the practical range led to a thermal conductivity of 1.05 W/m·K, a value which is believed to be associated with an optimal percolated network that served as efficacious thermal pathways in the fabricated nanocomposites. These results are believed to contribute to the potential employability of magnetic polymer nanocomposites (MPNCs) in electronic packaging applications.

The Synergistic Effects of Sio2 Nanoparticles and Organic Photostabilizers for Enhanced Weathering Resistance of Acrylic Polyurethane Coating

This study aims to evaluate the synergical effects of SiO2 nanoparticles (nano-SiO2) and organic photostabilizers (Tinuvin 384 (T384) and Tinuvin 292 (T292)) on the weathering resistance of acrylic polyurethane coating. Data obtained from infrared (IR), field emission scanning electron microscopy (FESEM), and weight loss of coatings (before and after aging test), suggest that the SiO2 nanoparticles play a dual role, as both reinforcer and UV absorber, thus improving effectively both the mechanical properties and the weathering resistance of polyurethane acrylic coatings. The nanocomposite coating containing 2 wt % nano-SiO2, 2 wt % T384, and 1 wt % T292 exhibits excellent weathering and abrasion resistances, offering a durable outdoor application.

Advances in Magnetic Noble Metal/Iron-Based Oxide Hybrid Nanoparticles as Biomedical Devices

The study of the noble metal magnetic hybrid nanoparticles is a really promising topic from both the scientific and the technological points of views, with applications in several fields. Iron oxide materials which are hybridized with noble metal nanoparticles (NPs) have attracted increasing interest among researchers because of their cooperative effects on combined magnetic, electronic, photonic, and catalytic activities. This review article contains a summary of magnetic noble metal/iron oxide nanoparticle systems potentially useful in practical biomedical applications. Among the applications, engineered devices for both medical diagnosis and treatments were considered. The preparation to produce different structures, as blends or core-shell structures, of several nanometric systems was also considered. Several characterization techniques available to describe the structure, morphology and different kinds of properties of hybrid nanoparticles are also included in this review.