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The development of stabilized silver nanoparticles (AgNP) is paramount in preventing the build-up of pathogenic biofilms. AgNP also requires a suitable support system to deliver the AgNP directly to the bacteria. Herein, AgNP-supported zeolite A was prepared via the in situ phytosynthesis method using Orthosiphon aristatus extract based on our previous work. The optimal condition of AgNP biosynthesis was achieved at 0.4 mL of the leaf extract in 10 mL AgNO3 1 mM. The AgNP was incorporated into zeolite A using the in situ approach. The developed materials were characterized by their porosity, surface area, thermogravimetry, and zeta potential. The morphology of samples was distinguished using field emission scanning electron microscopy (FESEM). The distribution of AgNP into the macroporous zeolite A was measured according to the reduction of specific pore volume from 0.1033 to 0.0346 cm3/g. Anti-biofilm and morphological assessments revealed that AgNP-supported zeolite A induced a good biofilm inhibition against bacteria Staphylococcus aureus (p < 0.0001) than Pseudomonas aeruginosa at 1 mg/mL because of less intolerance against AgNP. The biofilm formation was reduced by more than 50% and 15%, respectively, compared to the untreated bacteria. Bacteria tend to attach to the zeolite surface, and the AgNP incorporated in the zeolite would easily interact with the bacteria, inducing peptide bond alteration, which leads to structural disintegration. Therefore, these AgNP-supported zeolite materials exhibited the 'cut its source' strategy to capitulate the biofilm inhibition action. [ABSTRACT FROM AUTHOR]

A green approach for the biosynthesis of silver nanoparticles (AgNPs) was developed using Diplazium esculentum aqueous extract as green reductant. The bio-stabilized AgNPs were characterized by UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), and high-resolution transmission electron microscopy (HRTEM). The formation of AgNPs was indicated by the colour change and the absorption peak at 449 nm in the UV–Vis spectrum. FTIR spectral analysis suggested the possible biomolecules associated with the reduction of silver ions. The crystalline and face-centered cubic (fcc) structure of AgNPs was obtained by the XRD study. HRTEM analysis showed that the biosynthesized AgNPs composed of quasi-spherical, hexagonal, and ellipsoidal shapes with an average particle size of 23.385 ± 8.349 nm. The biosynthesized AgNPs exhibited good catalytic activity up to 91% reduction of Methylene blue (MB), which followed a reductive pathway rather than a photocatalytic route. The catalytic reduction follows a pseudo-first-order reaction with a rate constant of 0.1051 min-1. The disc diffusion technique (DDT) and minimal inhibitory concentration (MIC) results showed significant antibacterial capability against Gram-positive (Escherichia coli ATCC 11,229) and Gram-negative (Staphylococcus aureus ATCC 6538) bacteria. [ABSTRACT FROM AUTHOR]

Bioactivity and osteoblastic growth of hydroxyapatite (HA)-incorporated silica aerogels (SA) (HAESA) with different ratio of HA/SiO2 (0.1, 0.5, 1.0, and 1.3 HA/SiO2) were investigated. Bioactivity of HAESA was studied by immersing all samples in simulated body fluids (SBF) for 7 and 14 days. The recovered samples were then characterised using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy combined with energy dispersive X-ray analyser (FESEM–EDX) and the analysis of phosphate loss in the solution. These samples were also investigated for their effect on cell viability and proliferation abilities against normal human osteoblast cells in vitro after 24 and 48 h of exposure times. The HA/SiO2 ratio affected its bioactivity in which the bioactivity increased to 0.5 (HAESA-0.5) and declined at higher ratios (1.0 and 1.3). A similar trend was observed for cell viability and proliferation assays. HAESA-0.5 (HA/SiO2 ratio of 0.5), which possesses the optimal characteristics of SA and HA, resulted in the highest osteoblastic growth due to the synergistic effects between SA and HA. Thus, HAESA-0.5 could be an alternative biomaterial compared to silica- and HA-based biomaterials for bone implant application due to its higher bioactivity in SBF with the improved performance of osteoblast growth. Hydroxyapatite-incorporated silica aerogel with different weight ratio of HA/SiO2 (HAESA) was studied for their bioactivity in simulated body fluid and in vitro osteoblastic growth. Highlights: Hydroxyapatite-incorporated silica aerogels (HAESA) has higher bioactivity than silica aerogel. HAESA has higher bioactivity than free hydroxyapatite. HAESA increases cell viability and proliferation of normal human osteoblast cells. HAESA at 0.5 weight ratio has the highest bioactivity and biocompatibility. [ABSTRACT FROM AUTHOR]

The development of biomedical materials is increasing nowadays due to the increasing demands in medical area and various manmade advanced materials have been explored. In this study, the hydroxyapatite (HA) which is widely used biomaterial has been incorporated in silica aerogel (SA) through sol-gel ambient pressure drying (APD) technique using amorphous silica from rice husk ash. The HA incorporated SA (HAESA) samples with different weight ratio of HA/SiO2 (0.05, 0.1, 0.5, 1.0 and 1.3) were characterized and studied for their in vitro biocompatibility against normal human fibroblast cells. Based on the characterization results from Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis, transmission electron microscope and thermogravimetric analysis, the HAESA samples with lower weight ratio of HA/SiO2 (0.05, 0.1 and 0.5) were silica-rich materials compared to that of higher weight ratio (1.0 and 1.3) which were silica-deficient materials. This resulted in different effects towards in vitro cell viability where the silica-rich HAESA samples have higher biocompatibility compared to that of silica-deficient materials based on trypan blue and cell viability assays. The optimum weight ratio of HA/SiO2 was for HAESA-0.5 (weight ratio of 0.5) in which it has the characteristics of HA and SA, and this eventually resulted in the highest cell viability which is up to 180% after 48 h exposure. Therefore, it can be concluded that the right amount of HA incorporated in the SA network can be performed by using sol-gel APD technique and resulted in high biocompatibility which is suitable to be used as alternative biomaterial for soft tissue application. A series of hydroxyapatite (HA) incorporated silica aerogel with different weight ratio of HA/SiO2 was prepared via sol-gel ambient pressure drying (APD) technique, characterized and analyzed for their cell viability against normal human fibroblast cells. The weight ratio of 0.5 (HA/SiO2) was the optimum ratio where it has characteristics of silica aerogel and hydroxyapatite and resulted in the highest cell viability. Highlights: Hydroxyapatite incorporated silica aerogel (HAESA) was synthesized via sol-gel APD technique. Silica-rich HAESA have higher cytocompatibility against human fibroblast cells. HAESA with weight ratio of hydroxyapatite/SiO2 equal to 0.5 has the highest cytocompatibility. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose (BNC) currently has emerged as a potential biopolymer that can be used for various industrial applications. However, the major concern is the limitation of the bacteria used for BNC production on a larger scale. This study aimed to isolate and identify potential nanocellulose-producing bacteria from pineapple wastes. In this study, 11 isolates were screened and the F1 isolate, which produced the highest BNC yield was chosen for 16S rRNA sequencing. Based on the 16S rRNA analysis, Comamonas terrae YSZ sp. (OQ592726.1) was the best BNC producer with 1.68 ± 0.19 g/L yield. The physicochemical characteristics from FESEM analysis revealed that C. terrae YSZ sp. produced amorphous BNC, with fewer nanofibrils. The XRD analysis showed that the BNC produced had a 19.3% of crystallinity index. To the best of our knowledge, this is the first work reporting the isolation of C. terrae YSZ sp. from pineapple wastes with more amorphous regions providing an interesting alternative for heavy metal removal potentials.Graphical abstract: Bacterial nanocellulose (BNC) currently has emerged as a potential biopolymer that can be used for various industrial applications. However, the major concern is the limitation of the bacteria used for BNC production on a larger scale. This study aimed to isolate and identify potential nanocellulose-producing bacteria from pineapple wastes. In this study, 11 isolates were screened and the F1 isolate, which produced the highest BNC yield was chosen for 16S rRNA sequencing. Based on the 16S rRNA analysis, Comamonas terrae YSZ sp. (OQ592726.1) was the best BNC producer with 1.68 ± 0.19 g/L yield. The physicochemical characteristics from FESEM analysis revealed that C. terrae YSZ sp. produced amorphous BNC, with fewer nanofibrils. The XRD analysis showed that the BNC produced had a 19.3% of crystallinity index. To the best of our knowledge, this is the first work reporting the isolation of C. terrae YSZ sp. from pineapple wastes with more amorphous regions providing an interesting alternative for heavy metal removal potentials. [ABSTRACT FROM AUTHOR]