Background Discoloration affects glass ionomer cement (GIC) color stability due to its brittle nature and microporosity. To counter this, incorporating alternative materials is essential for maintaining color stability. Aim This study aims to determine the color stability and gloss of GIC modified with bioactive chitosan, titanium, zirconia, and hydroxyapatite nanoparticles before and after artificial aging. Materials and methods  The study was conducted at Saveetha Research Centre, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, located in Chennai, India. Green-mediated chitosan, titanium, zirconia, and hydroxyapatite (Ch-Ti-Zr-HA) nanoparticles were synthesized using the one-pot synthesis technique. Forty-eight disc-shaped specimens were prepared by incorporating the obtained nanoparticles (nanocomposite) into the GIC, with a diameter of 5 mm and thickness of 2 mm. The specimens were prepared in different concentrations (3%, 5%, and 10%) designated as group I, group II, and group III, respectively. Group IV, serving as the control, consisted of conventional GIC without any modifications. Following preparation, scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) microanalysis confirmed sample elements, and the specimens were submerged in distilled water for a duration of 24 hours prior to the commencement of testing. Subsequently, the specimens underwent artificial aging (thermocycling), between temperatures of 5°C and 55°C, for a total of 30,000 cycles, with a 30-second dwell time. Color change and gloss characteristics were assessed both after 24 hours and following thermocycling using a spectrophotometer and glossometer, respectively. The average color change parameter (ΔE) was measured using Adobe Photoshop. The data obtained were subjected to statistical analysis using an unpaired t-test. Results Significant color stability variations were observed post thermocycling (P = 0.001). Group 2 (5%) exhibited minimal delta E difference (0.508 ± 0.105), indicating superior color stability, while group 4 (control) had maximum difference (1.15 ± 0.187), indicating lower stability. Gloss tests confirmed GIC\'s polishability, where there were significant differences among all the groups. Conclusion It can be concluded that 5% nanoparticle-modified GIC has better color stability and gloss than conventional GIC. Further studies are needed to analyze the color stability and gloss through dentifrices and other beverages.

In this study, chitosan-gelatin-monetite (CGM)-based electrospun scaffolds have been developed that closely mimicked the microstructure and chemical composition of the extracellular matrix of natural bone. CGM-based nanofibrous composite scaffolds were prepared with the help of the electrospinning technique, post-cross-linked using ethyl(dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide solution to improve their stability in an aqueous environment. The prepared chitosan/gelatin (CG) scaffold showed an average fiber diameter of 308 ± 17 nm, whereas 5 and 7 wt% monetite containing CGM5and CGM7scaffolds, exhibited an average fiber diameter of 287 ± 13 and 265 ± 9 nm, respectively, revealing the fine distribution of monetite particles on the fibrous surface. The distribution of monetite nanoparticles onto the CG nanofibrous surface was confirmed using x-ray diffraction, Fourier transform infrared, and EDAX. Moreover, the addition of 7 wt% monetite into the CG electrospun matrix increased their ultimate tensile strength from 7.62 ± 0.13 MPa in the CG scaffold to 14.34 ± 0.39 MPa in the CGM7scaffold. Simulated body fluid study and staining with alizarin red S (ARS) confirmed the higher mineralization ability of monetite-containing scaffolds compared to that revealed by the CG scaffold. The monetite incorporation into the CG matrix improved its osteogenic properties, including pre-osteoblast MG-63 cell adhesion, proliferation, and differentiation, when seeded with the cells. A higher degree of cellular adhesion, spreading, and migration was observed on the monetite-incorporated CG scaffold than that on the CG scaffold. From 3-(4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide) MTT assay, alkaline phosphatase activity, ARS staining, and immunocytochemistry study, the cultured cells discovered a more conducive microenvironment to proliferate and subsequently differentiate into osteoblast lineage in contact with CGM7nanofibers rather than that in CGM0and CGM5.In-vitroresults indicated that electrospun CGM-based composite scaffolds could be used as a potential candidate to repair and regenerate new bone tissues.

Selenium nanoparticles (SeNPs) have antimicrobial and antifungal activity. SeNPs using Se resistant bacteria is a low cost and eco-friendly technology. Fungal contamination of wood during drying is one of the main causes of economic losses in the wood industry. The bacterium Delftia sp. 5 resistance to Se and its ability to produce SeNPs able to inhibit the growth of the wood brown-rotting fungus Oligoporus pelliculosus was analyzed. The strain showed an optimal SeNPs production when selenite concentration was 160 mg L -1. The SeNPs were spherical with an average size 192.33 ± 8.6 nm and a zeta potential of -41.4 ± 1.3 nm. The SeNPs produced by Delftia sp. 5 (33.6 ± 0.1 mg L -1 Se) inhibited the growth of O. pelliculosus in agar plates and in Nothofagus pumilio (Lenga) wood samples. Delftia sp. 5 SeNPs could be used for embedding lenga wood prior to drying for preventing the growth of the deteriorating fungi O. pelliculosus.

Respiratory syncytial virus (RSV) is the most common cause of viral bronchiolitis among children worldwide, yet there is no vaccine for RSV disease. This study investigates the potential of cube and sphere-shaped cerium oxide nanoparticles (CNP) to modulate reactive oxygen (ROS) and nitrogen (RNS) species and immune cell phenotypes in the presence of RSV infection in vitro and in vivo. Cube and sphere-shaped CNP were synthesized by hydrothermal and ultrasonication methods, respectively. Physico-chemical characterization confirmed the shape of sphere and cube CNP and effect of various parameters on their particle size distribution and zeta potential. In vitro results revealed that sphere and cube CNP differentially modulated ROS and RNS levels in J774 macrophages. Specifically, cube CNP significantly reduced RSV-induced ROS levels without affecting RNS levels while sphere CNP increased RSV-induced RNS levels with minimal effect on ROS levels. Cube CNP drove an M1 phenotype in RSV-infected macrophages in vitro by increasing macrophage surface expression of CD80 and CD86 with a concomitant increase in TNFα and IL-12p70, while simultaneously decreasing M2 CD206 expression. Intranasal administration of sphere and cube-CNP were well-tolerated with no observed toxicity in BALB/c mice. Notably, cube CNP preferentially accumulated in murine alveolar macrophages and induced their activation, avoiding enhanced uptake and activation of other inflammatory cells such as neutrophils, which are associated with RSV-mediated inflammation. In conclusion, we report that sphere and cube CNP modulate macrophage polarization and innate cellular responses during RSV infection.

Bacterial pneumonia is one of the leading causes of death worldwide and exerts a significant burden on health-care resources. Antibiotics have long been used as first-line drugs for the treatment of bacterial pneumonia. However, antibiotic therapy and traditional antibiotic delivery are associated with important challenges, including drug resistance, low bioavailability, and adverse side effects; the existence of physiological barriers further hampers treatment. Fortunately, these limitations may be overcome by the application of nanotechnology, which can facilitate drug delivery while improving drug stability and bioavailability. This review summarizes the challenges facing the treatment of bacterial pneumonia and also highlights the types of nanoparticles that can be used for antibiotic delivery. This review places a special focus on the state-of-the-art in nanomaterial-based approaches to the delivery of antibiotics for the treatment of pneumonia.

The demand for metallic nanoparticles synthesized using green methods has increased due to their various therapeutic and clinical applications, and plant biotechnology may be a potential resource facilitating sustainable methods of AgNPs synthesis. In this study, we evaluate the capacity of extracts from Randia aculeata cell suspension culture (CSC) in the synthesis of AgNPs at different pH values, and their activity against pathogenic bacteria and cancer cells was evaluated. Using aqueous CSC extracts, AgNPs were synthesized with 10% (w/v) of fresh biomass and AgNO3 (1 mM) at a ratio of 1:1 for 24 h of incubation and constant agitation. UV-vis analysis showed a high concentration of AgNPs as the pH increased, and TEM analysis showed polydisperse nanoparticles with sizes from 10 to 90 nm. Moreover, CSC extracts produce reducing agents such as phenolic compounds (162.2 ± 27.9 mg gallic acid equivalent/100 g biomass) and flavonoids (122.07 ± 8.2 mg quercetin equivalent/100 g biomass). Notably, AgNPs had strong activity against E. coli, S. pyogenes, P. aeruginosa, S. aureus, and S. typhimurium, mainly with AgNPs at pH 6 (MIC: 1.6 to 3.9 µg/mL). AgNPs at pH 6 and 10 had a high antiproliferative effect on cancer cells (IC50 < 5.7 µg/mL). Therefore, the use of cell suspension cultures may be a sustainable option for the green synthesis of AgNPs.

The aim of the study was to examine the applicability of bioactive and antibacterial nanoparticles to an experimental adhesive. The adhesive (60 wt% BisGMA, 15 wt% TEGDMA, 25 wt% HEMA) was mixed with combinations of 5 wt% methacryl-functionalized polyhedral oligomeric silsesquioxane (MA-POSS) and one kind of bioactive/antibacterial nanoparticles: 1 wt% core-shell silica-silver nanoparticle (SiO2@Ag), 1 wt% bioactive glass with bismuth (BAG-Bi) or 1 wt% calcium phosphate (CAP). Pure adhesive served as control. The physicochemical (degree of conversion (DC), linear shrinkage (LS), shear and complex viscosity, water sorption (WS), sol fraction (SF)), biological (antimicrobial effect) and bioactive (mineral precipitation) properties were investigated. DC and LS remained unchanged. The combination of BAG-Bi/MA-POSS resulted in a significantly increased WS and SF compared to control. In addition, the combination of CAP/MA-POSS slightly increased the shear viscosity of the adhesive. The addition of the nanoparticles did not influence the antimicrobial effects compared to the pure adhesive. Improved mineral inducing capacity could be detected in all nanoparticle combinations. The combination of bioactive and/or antibacterial nanoparticles showed improved mineral inducing capacity, but no antibacterial properties. The material properties were not or only slightly affected.

Microbiota plays a crucial role in human health and disease; therefore, the modulation of this complex and yet widely unexplored ecosystem is a biomedical priority. Numerous antibacterial alternatives have been developed in recent years, imposed by the huge problem of antibioresistance, but also by the people demand for natural therapeutical products without side effects, as dysbiosis, cyto/hepatotoxicity. Current studies are focusing mainly in the development of nanoparticles (NPs) functionalized with herbal and fruit essential oils (EOs) to fight resistant pathogens. This is due to their increased efficiency against susceptible, multidrug resistant and biofilm embedded microorganisms. They are also studied because of their versatile properties, size and possibility to ensure a targeted administration and a controlled release of bioactive substances. Accordingly, an increasing number of studies addressing the effects of functional nanoparticles and plant products on microbial pathogens has been observed. Regardless the beneficial role of EOs and NPs in the treatment of infectious diseases, concerns regarding their potential activity against human microbiota raised constantly in recent years. The main focus of current research is on gut microbiota (GM) due to well documented metabolic and immunological functions of gut microbes. Moreover, GM is constantly exposed to micro- and nano-particles, but also plant products (including EOs). Because of the great diversity of both microbiota and chemical antimicrobial alternatives (i.e., nanomaterials and EOs), here we limit our discussion on the interactions of gut microbiota, inorganic NPs and EOs. Impact of accidental exposure caused by ingestion of day care products, foods, atmospheric particles and drugs containing nanoparticles and/or fruit EOs on gut dysbiosis and associated diseases is also dissected in this paper. Current models developed to investigate mechanisms of dysbiosis after exposure to NPs/EOs and perspectives for identifying factors driving EOs functionalized NPs dysbiosis are reviewed.

Toll-like receptor (TLR) activation in macrophages plays a critical role in the pathogenesis of acute lung injury (ALI). While TLR inhibition is a promising strategy to control the overwhelming inflammation in ALI, there still lacks effective TLR inhibitors for clinical uses to date. A unique class of peptide-coated gold nanoparticles (GNPs) is previously discovered, which effectively inhibited TLR signaling and protected mice from lipopolysaccharide (LPS)-induced ALI. To fast translate such a discovery into potential clinical applicable nanotherapeutics, herein an elegant strategy of \"nano-enabled drug repurposing\" with \"nano-targeting\" is introduced to empower the existing drugs for new uses. Combining transcriptome sequencing with Connectivity Map analysis, it is identified that the proton pump inhibitors (PPIs) share similar mechanisms of action to the discovered GNP-based TLR inhibitor. It is confirmed that PPIs (including omeprazole) do inhibit endosomal TLR signaling and inflammatory responses in macrophages and human peripheral blood mononuclear cells, and exhibits anti-inflammatory activity in an LPS-induced ALI mouse model. The omeprazole is then formulated into a nanoform with liposomes to enhance its macrophage targeting ability and the therapeutic efficacy in vivo. This research provides a new translational strategy of nano-enabled drug repurposing to translate bioactive nanoparticles into clinically used drugs and targeted nano-therapeutics for ALI.

BACKGROUND: Macrophages regulate the processes of inflammation and tissue regeneration/repair through their plasticity and phenotypes of different activation states. Previous studies have shown that disinfection of lipopolysaccharide (LPS)-contaminated dentin with photoactivated rose bengal-functionalized chitosan nanoparticles (CSRBnps) in vivo supported neotissue formation without signs of inflammation and root resorption. The aim of this study was to understand the mechanism underlying CSRBnp-guided attenuation of inflammation in LPS-contaminated dentin using macrophage polarization as an indicator of inflammation and repair.
METHODS: To quantify the polarized macrophage populations, M1/M2-specific surface markers CD68, CD80, and CD206 and transcriptional factors signal transducer and activator of transcription (STAT) 1, STAT3, and STAT6 were determined using immunohistochemistry among previously obtained root specimens implanted into mandibles of guinea pigs for 4 weeks. In group 1, the canals were not inoculated; in group 2, the canals were inoculated with Pseudomonas aeruginosa LPS; in group 3, the canals were inoculated and disinfected with sodium hypochlorite; in group 4, the canals were inoculated and disinfected with sodium hypochlorite and calcium hydroxide; and in group 5, the canals were inoculated and disinfected with sodium hypochlorite, and CSRBnps (300 μg/mL) with photoactivation (λ = 540 nm, 40 J/cm2) were analyzed.
RESULTS: An increased expression of M2-specific markers was observed in the group treated with CSRBnps compared with the groups treated with either conventional or no root canal disinfection. A statistically significant population of macrophages expressing both M1- and M2-specific markers was observed in all the tested groups.
CONCLUSIONS: Disinfection of LPS-contaminated dentin with CSRBnps demonstrated M2-type polarization of macrophages, which corresponded to repair and neotissue formation.