Key Engineering Materials Vol. 840

Abstract: Dengue is a global health problem which predominantly affected the tropical and subtropical region of Asia, Africa, and America. However, there are no available antiviral agents to treat dengue virus (DENV) infection. This study was conducted to utilize natural product compounds as an inhibitor of NS5 Methyltransferase, a viral protein which plays an essential role in the synthesis of DENV RNA. The natural product compounds were collected from the Universal Natural Product Database (UNPD), totaling 229,000 compounds. The in silico screening of the natural product compounds was performed by molecular docking simulation method, which simulates the interaction of the compounds on the active site of the NS5 methyltransferase. From the molecular docking simulation, about 51 compounds showed better affinity and interaction compared to the standard compound, S-Adenosyl-L-Homocysteine (SAH). Then, a series of pharmacological tests were performed to find the best drug candidates by employing DataWarrior and SwissADME software. Finally, three natural product compounds, namely UNPD98966, UNPD183023, and UNDP104952, were regarded as the best inhibitor against NS5 methyltransferase based on its molecular affinity and interaction. These compounds also showed potential as drug candidates due to their desirable pharmacological properties.

Abstract: Some benzylidenehydrazides (3a-e) have been synthesized in three reaction steps from anthranilic acid in good yields, about 70% - 99%. The structures of the synthesized compounds were analyzed using spectroscopic methods. The compounds were evaluated its activity against human lung cancer, A549 cell line by MTT method and studied its molecular docking onto the protein tyrosine kinase (PDB ID: 1M17) by using Molegro® vs. 5.5. The data showed that N-(2-(2-(4-nitrobenzylidene)hydrazinecarbonyl)phenyl)benzamide (3d) which synthesized in 70% yield and has the highest activity on inhibiting the growth of A549 cell line with IC₅₀ 10.9μg/mL, which was linier with our in silico study. Compound 3d has the smallest RS value -94.44 kcal/mol, lower than selected Ligand, Erlotinib.

Abstract: Actinomycetes are filamentous Gram-positive bacteria that potential sources of antimicrobial substances. The aim of this study was to isolate actinomycetes from different soil types in Enggano Island and screened their antimicrobial activity. The phenol method with 802 medium and humic acid vitamin (HVA) medium was used to isolate the actinomycetes. Furthermore, molecular identifications were performed based on 16s rRNA gene sequence. Antimicrobial activity screening was performed against Bacillus subtilis BTCC B.612, Escherichia coli BTCC B.612, Micrococcus luteus BTCC B.552, Staphylococcus aureus BTCC B.611, and Candida albicans BTCC Y.33 by using the agar plug diffusion method. Fifty-six actinomycetes isolates were obtained from 11 soil types. Most of the isolates were Streptomyces genus with species S. hydrogenans, S. coelicolor, and S. koyangensis, which have similarities in the 16S rRNA gene sequence ranging from 98 -100%. Among isolates screened for their antimicrobial activity, five isolates, i.e. SMP 6, SMP 7b, SMP 18, SHP 9-3, and SHP 22-1a showed a potential activity against test microorganisms selected. All of isolates were more active against C. albicans compared with the tested bacteria. Further study will be conducted to isolate active substances against C. albicans.

Abstract: Nano-hydroxyapatite was synthesized by coprecipitation method and tested its antibacterial properties. Nano-hydroxyapatite was synthesized using CaO precursors from snakehead (Channa striata) fish bones and (NH₄)₂HPO₄. The synthesis was carried out with temperature variations of 30, 60, 80, and 100 °C. Antibacterial activity was determined using two types of bacteria, namely gram-positive and gram-negative. The XRD spectra show that the highest peak is hydroxyapatite synthesized at a temperature of 100 °C. Hydroxyapatite produced from various synthesis temperatures has the size of nanoparticles in the range 37.32-49.27 nm. The nano-hydroxyapatite functional groups are characterized using FTIR, the analysis indicate the presence of OH, CO₃^2‒ and PO₄^3‒. The molar ratio Ca/P is obtained of 1.71 approaching theoretical hydroxyapatite of 1.67. The resulted nano-hydroxyapatite has significant antibacterial properties to Escherichia coli and Staphylococcus aureus.

Abstract: Fiber-reinforced composite resin (FRC) is gaining popularity as dental filling material. In the oral cavity, it will contact with the oral environment including oral cleansing agents. This research was aimed to determine the effect of mouthwash on the compressive strength of FRC. The materials used were E-glass FRC (EverX Posterior, GC Corp, Japan), alcohol mouthwash (Original Listerine, Johnson&Johnson, Indonesia), alcohol-free mouthwash (Listerine Cool Mint Zero, Johnson&Johnson, Indonesia). Forty-five FRCs were made in cylindrical shapes. Specimens were divided into 2 groups of mouthwash immersion: alcohol and alcohol-free mouthwash. The groups were sub-grouped by 0, 6, 12, and 24 h immersion. Samples were recorded for compressive strength by Universal Testing Machine. The data were analyzed by ANOVA. The result of compressive strength values (MPa) were (alcohol mouthwash): 293.59±30.54 (0 h), 284.43±46.91 (6 h), 268.71±44.66 (12 h), 252.19±31.49 (24 h); (alcohol-free mouthwash): 294.12±28.17 (0 h), 287.30±35.56 (6 h), 273.32±41.94 (12 h), 260.82±40.67 (24 h). Statistical analysis revealed there was no significant influence of mouthwash type (alcohol or alcohol-free mouthwash), immersion duration (0, 6, 12, 24 h), and combination of mouthwash type and immersion duration (p>0.05) to the compressive strength of FRCs. The conclusions were the mouthwash types, immersion duration, and combination of mouthwash type and immersion duration did not influence the compressive strength of E-glass FRC

Abstract: Porosity and interconnectivity play an important role in the success of tissue engineering because it affects cells to live and grow. Coral has been used as a bone replacement material because the structures resemble bone and have mechanical bone properties. In this study, the synthetic coral scaffold was developed to mimic the natural coral. This study aims to investigate the porosity of the scaffold and its biocompatibility while it is attached to human gingival cells. Synthetic coral scaffold in various compositions were prepared, porosity percentage measurement and human gingival cell attachment test were done. An optimum ratio of the scaffold with gelatin: CaCO₃, having the highest porosity and cell attachment is obtained in 5:5. The result of this study presented that synthetic coral scaffold could provide the microenvironment to cells for life because it is supported by the highest percentage of porosity.

Abstract: In this research, we report the use of free sodium and less Fe ion silica (SiO₂) for preparation of White Mineral Trioxide Aggregate (WMTA). SiO₂ was extracted from rice husk ash (RHA) using NaOH 2 M and HCl 37% (v/v) and removal of Na was performed by washing the extracted SiO₂ using deionized water with various volumes and techniques. Before extraction, RHA was calcined at a temperature of 700 °C for 3 h. Preparation of WMTA began with mixing the extracted SiO₂ 20%, CaO 60%, Al₂O₃ 2%, and Bi₂O₃ 18% (w/w). The mixture was calcined at temperatures of 1100 °C for 4 h, grounded to produce WMTA 200 mesh in size and then was characterized using Fourier Transformed Infrared (FTIR) spectrophotometer, X-ray Diffraction (XRD) and Scanning Electron Microscopy-Energy Dispersion X-ray (SEM-EDX). The WMTA characteristics were compared to that of the commercial WMTA ProRoot. The result shows that the silica that was potential as the silica source for WMTA preparation was extracted from RHA involving sonication and washing with 360 mL of deionized water per 10 g of RHA. It contained SiO₂ of 94.2%, Fe₂O₃ of 0.03%, no Na₂O, and the particle size of 1.51±0.46 µm. The characterization of WMTA shows that produced WMTA contained tricalcium silicate (C₃S), dicalcium silicate (C₂S), tricalcium aluminate (C₃A) and BiO₂, which is comparable to the commercial WMTA ProRoot.

Abstract: The present work demonstrates a low-cost route to produce hydroxyapatite (HAp) from fish bones (natural source) by a simple heat-treatment process. The produced HAp was characterized by X-ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR). Energy Dispersive X-ray (EDX) analysis obtained elemental composition that confirmed the presence of Ca and P; then the Ca/P mole ratio was calculated. XRD analysis from Chanos chanos and Calarias batracus bone has produced the diffraction peaks at 31.8°, 32.1°, and 32.9° that corresponded to the HAp phase. The presence of functional groups, PO₄^3‒ and OH^‒, has been confirmed by FTIR spectra that arecharacteristics of HAp. EDX analysis has shown that the Ca/P mole ratio was similar to the Ca/P mole ratio of the HAp’s stoichiometry (1.66). But actually, not all fish bones can produce pure HAp after the heat-treatment process, such as Tylosurus crocodilus bone. Based on XRD analysis from the main diffraction peak form is a β-TCP phase

Abstract: One of the requirements of endodontic material is to have good biocompatibility of pulp tissue that has direct contact with the material, to promote the process of tissue repair. Reversible pulpitis needs direct pulp capping treatment with medicament materials i.e. RMGIC (Resin-Modified Glass Ionomer Cement) and MTA (Mineral Trioxide Aggregate) which are used as the gold standard for direct pulp capping treatment. Both of the materials have several disadvantages including the necrotic tissue in the area has direct contact with the pulp so that it affects the successful treatment results. Nowadays, the new materials are being developed which are expected to improve the existing material deficiencies. In this study, fibroin was extracted from Bombyx mori L. cocoon. This study aimed to examine the biocompatibility of fibroin as a new pulp capping material with RMGIC (Fuji II LC, GC, Japan) and MTA (Rootdent, Technodent, Russia). An experimental study was conducted using extracted human primary dental pulp cells in vitro through orthodontic treatment. A methyl thiazole tetrazolium (MTT) assay was employed to test biocompatibility using ELISA Reader 590 nm wavelengths for 24, 48, and 72 h, respectively. The findings showed that the biocompatibility of fibroin had the highest value of all. In conclusion, fibroin biocompatibility toward MTA and RMGIC as pulp capping materials can be aligned, however, there were no significant differences.

Abstract: White Mineral Trioxide Aggregate (WMTA) using precipitated CaCO₃ (PCC) from limestone has been synthesized. PCC in calcite structure was extracted from limestone by calcination at 900 °C for 3 h, dissolved in 0.8 M nitric acid solution and followed with carbonation for 60 minutes. PCC was used for the synthesis of WMTA by mixing with tetraethoxyorthosilicate, bismuth oxide, aluminum oxide, catalyst of with HNO₃ and NH₃ solution and thermally treated at 1100 °C for 3 h. The products were characterized with Thermal Gravimetric Analysis-Differential Thermal Analysis (TGA-DTG), X-ray Diffraction (XRD), Frontier-Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and X-ray Fluorescence (XRF). The results showed that the PCC dominated calcite structure was obtained with 75.25% in yield and 99.42% in purity. The WMTA has been successfully synthesized by low thermal treatment at 1100 °C using catalysts of HNO₃ and NH₃ solution, proven by the presence of tricalcium silicate (C₃S), dicalcium silicate (C₂S), tricalcium aluminate (C₃A), and Bi₂O₃ in WMTA.