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In this research, gold nanoparticles were synthesized using the green synthesis method with the bioreduction extract of Basella alba leaf infusion. This research aims to characterize gold nanoparticles synthesized using UV-Vis spectroscopy and TEM and assess their antioxidant activity, which is quantified by the IC50 value. The UV-Vis spectrophotometric characterization of the gold nanoparticles revealed an absorption peak at a maximum wavelength of 543 nm. TEM characterization indicated a particle diameter of 9.463 ± 2.273 nm. The antioxidant activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) reduction method with concentration variations of 2.5, 5, 10, and 20 ppm, resulting in reduction percentages of 40.6%, 44.3%, 57.4%, and 77.9%, respectively, and an IC50 value of 7.05 μg/mL, indicating very strong antioxidant activity. Based on these findings, it can be concluded that Basella alba leaf infusion extract is effective as a biological reducing agent in synthesizing gold nanoparticles, and the resulting nanoparticles show significant potential as antioxidants for reducing free radicals.

Gold nanoparticles are inorganic metal materials in suspended solutions with a particle size reduction process to the 5-400 nm nanoscale range. Gold nanoparticles can be synthesized using the green synthesis method using a bioreductor of butterfly pea leaf infusion extract, which can be used as an antioxidant. This study aimed to determine the characteristics of gold nanoparticles using a UV-Vis spectrophotometer and TEM and to determine the antioxidant strength of gold nanoparticles through the IC50 value. This study used 20, 10, 5, and 2.5 ppm concentration variations. The results of the characterization of gold nanoparticles using a UV-Vis spectrophotometer showed a maximum wavelength of 550 nm, and the results of the TEM test showed a particle diameter of 6.58 nm. The antioxidant activity test was carried out using the 1,1-diphenyl-2-picryhydrazyl (DPPH) quenching method, resulting in % quenching at a concentration of 20, 10, 5 and 2.5 ppm of 76.3; 70.6; 85.5; and 92.9% and an IC50 value of 0.25 ppm which is included in strong antioxidants. It can be concluded that gold nanoparticles synthesized using butterfly pea leaf extract have the potential to be an effective antioxidant agent.

Gold nanoparticles (AuNPs) are small-sized materials important in various commercial and industrial applications. Several methods have been developed to synthesise AuNPs. This study was conducted by synthesizing AuNPs using HAuCl4 as a precursor and red shoot leaf extract as a bioreductor. The concentrations of AuNPs used were 20, 10, 5, and 2.5 ppm. Characterization of gold nanoparticles at a concentration of 20 ppm was carried out using a UV-Vis spectrophotometer to measure the maximum wavelength and Transmission Electron Microscopy (TEM) to determine particle size. Antioxidant activity at 20, 10, 5, and 2.5 ppm was determined by measuring free radical capture activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The results showed that gold nanoparticles had a maximum wavelength of 530 nm with a ruby red color and an average particle size of 14.907 nm. The synthesized AuNPs showed high antioxidant activity: 99.6% (20 ppm), 98.9% (10 ppm), 96.7% (5 ppm), and 91.0% (2.5 ppm), indicating that higher concentrations of AuNPs resulted in more significant free radical scavenging. This study successfully synthesized gold nanoparticles using red shoot leaf extract as an environmentally friendly bioreduction. The resulting nanoparticles have a nanometer particle size with very high antioxidant activity, especially at a concentration of 20 ppm. The method used in this study offers a more environmentally friendly alternative for synthesizing gold nanoparticles, which previously often used hazardous chemicals. The use of red shoot leaf extract as a bioreductor has not been widely reported in the literature, thus providing a new contribution to green nanotechnology. Further research is recommended to explore the potential applications of gold nanoparticles synthesized by this method in medical and other industrial fields. In addition, additional studies are needed to optimize the synthesis conditions and more in-depth characterization of the stability and toxicity of gold nanoparticles in practical applications.

ZnO nanoparticles were synthesized using the precipitation method and using water extract of Crescentia cujete L leaves as a capping agent. ZnO nanoparticles with a hexagonal wurtzite structure were successfully synthesized with low production cost and environmentally friendly. According to XRD characterization, there is no impurity peak, indicating the ZnO nanoparticles have high purity and crystallinity. SEM images show the morphology of ZnO nanoparticles with semi-spherical shapes and an average size of 32.49 nm. The photocatalytic activity of ZnO nanoparticles was evaluated using a UV A lamp as a source of photonic energy toward methylene blue dye. Various irradiation times were carried out from 0, 10, 20, 30, 40, to 50 minutes, and a UV spectrophotometer was used to detect the concentration of methylene blue remains in collected samples. Increasing the irradiation times leads to increasing the photocatalytic activity of ZnO nanoparticles. At 50 minutes of exposure to a UV A lamp, the degradation percentage of methylene blue dye is 36.37%.

There are numerous green methods for synthesizing silver nanoparticles using plant extracts such as leaves, flowers, stems, and fruit extracts. However, most of those synthesized have weaknesses such as slow reduction and inefficient time. This study used a microwave to accelerate the reduction process of Ag+ ions into Ag0 nanoparticles using an aqueous extract of Citrus sinensis peels. A heating time of 5 minutes produces silver nanoparticles in optimal condition with a color change from yellow to reddish brown. According to UV-Vis, silver nanoparticles at power 100 W and 300 W show peaks at 404 nm and 406 nm. FTIR indicates that phytochemical compounds are involved in the reduction of nanoparticles. XRD shows silver nanoparticles are FCC crystalline. TEM reveals that power 100 W yields an average diameter of 12 nm while 300 W shows a smaller diameter of 5 nm.

A novel preparation of silver nanoparticles using Morus nigra leaves extract, as opposed to the physical and chemical methods had been used in this work. Their active phytochemical compounds will reduce Ag+ and form AgNPs (Ag0). A peak spectrum at 460 nm was formed and confirmed as the Surface Plasmon Resonance (SPR). Vibration at 1643 cm-1 and 3286 cm-1 which characteristic of C=C bonds and (-OH) hydroxyl groups, respectively. An X-ray diffraction (XRD) examination of silver with good crystallinity revealed its distinctive pattern. According to the results of transmission electron microscopy (TEM), the produced AgNPs-Morus nigra leaves extract were between 10 and 20 nm in size. Using L-dihydroxyphenylalanine (L-DOPA) as the substrate, the synthesized AgNPs-Morus nigra were tested for their tyrosinase inhibitory activity, and the results are substantial when compared to kojic acid as a control. The percentages of inhibition from crude extract, AgNPs, and kojic acid at 100 µg/mL are to be found at 12.10 %, 64.80 %, and 59.84 %, respectively. Based on the results of this work, AgNPs can be produced by utilizing a green synthesis method with leaves extract, making them a promising candidate for use in medicine and cosmetics.

Silver nanoparticles (AgNPs) have become popular due to their unique properties that can be used as biosensors, composite fibers, semiconductor materials, and other medical applications. Green synthesis of AgNPs using natural reagents from plant extract offers advantages as an efficient and environmentally friendly technique by which the compounds from the extract perform as bio-reductor for silver ions and the capping agent for stabilizing the AgNPs. Therefore, the purpose of the study was to conduct the synthesis of AgNPs by utilizing an extract of Capsicum chinensie Jacq as the bioreductor. The effect of extract concentrations, duration of exposure to sunlight, and temperatures on AgNPs formation was studied to obtain the optimum synthesis condition. The biosynthesized AgNPs characteristics were analyzed using UV-Vis Spectrophotometry, FTIR, SEM, X-Ray Diffraction, and PSA. The results showed that the higher extract concentration produced smaller AgNPs. The synthesis under sunlight exposure showed more product of AgNPs compared to heating on a hot plate. The optimum conditions of biosynthesis of AgNPs were attained at the volume ratio of extract (20%) and AgNO3 (1mM) of 1:1 and duration of sunlight exposure of 90 min, resulting in AgNPs characterized with maximum wavelength 422 nm and average particle sizes of 67.94 nm.

The purpose of this study was to determine the effect of silver nanoparticles (AgNPs) from different green synthesis medium and their various particle sizes on antibacterial activity. The article review method compares the results of 11 studies obtained from the PubMed database, Web of Science, and ScienceDirect indexed by Scopus in the last five years. The search was conducted based on the phrases nanoparticles, antibacterial, Green synthesis, and AgNPs. Green synthesis of AgNPs with various plant extracts produces different sizes of nanoparticles. The smallest size AgNPs were obtained in the range of 5-15 nm and an average of 13 nm extracted using the leaves of the Pacific Yew tree (Taxus brevifolia). Meanwhile, AgNPs with the best antibacterial effectiveness were obtained from the Blume flower extract (Wedelia urticifolia) measuring less than 30 nm providing a zone of inhibition for S. aureus, K. pneumoniae, E. coli, and P. aeruginosa bacteria.

A simple and scalable liquid-based method was developed to produce a nanocomposite photocatalyst which was comprised of Fe3O4 nanoparticles (4-5 nm) decorated indium hydroxide nanorods (mean width 33 nm and average aspect ratio 2-3). The nanocomposite was produced at 25 ℃ in water via a hydroxide-induced co-precipitation ensued by a cathodic reduction during which the non-magnetic Fe(OH)3 intermediate was reduced to magnetic Fe3O4 at 20 V within 1 h. The incorporation of Fe3O4 nanoparticles served to bestow magnetic recoverability to the photocatalyst and helped enhance visible light absorption simultaneously. Interestingly, the addition of Fe3+ led to the formation of In(OH)3 nanorods rather than the commonly observed nanocubes. In comparison to the In(OH)3 system having a band gap of 4.60 eV), the band gap of the Fe3O4/In(OH)3 nanocomposite produced was determined to be 2.85 eV using the Tauc’s plot method. The effective reduction in band gap is expected to allow better absorption of visible light which in turns should help boost its photocatalytic performance. The Fe3O4/In(OH)3 nanocomposite was structurally characterized using a combination of PXRD, FESEM, EDS, and TEM and its paramagnetic property was proven with a positive mass susceptibility measured to be 1.30´10−5 cm3.g−1. Under visible light, a photocatalytic degradation efficiency of 83% was recorded within 1 hr for the nanocomposite using methylene blue as a dye. The photocatalytically-active Fe3O4/In(OH)3 should have good potential in visible-light driven waste water degradation once further optimized. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The ability of cotton fabrics to absorb water creates several problems, such as providing an environment for bacterial growth. Antibacterial properties of textiles can be conducted by coating with nanoparticles with antibacterial activity. This study aimed to synthesize ZnO via green process nanoparticles using avocado seed extract (Persea americana), then characterize and evaluate its antibacterial activity on cotton fabrics. This research began with extracting avocado seed powder with distilled water. Then the avocado seed extract was mixed with Zn(CH3COO)2.2H2O and heated in a water bath at 70°C. The mixture was stirred while NaOH was added until the mixture reached pH 7, 8, and 9. The FTIR measurement of the avocado seed extract showed the presence of free hydroxyl and amino groups that act as reducing agents, capping agents, and stabilizers in the synthesis of ZnO nanoparticles. The XRD pattern of synthesized ZnO nanoparticles was hexagonal. The SEM results showed that the morphology of ZnO nanoparticles was spherical, with a particle size of 19.965 nm. Antibacterial activity was carried out on the cotton cloth coated with ZnO nanoparticles, resulting in an inhibition zone of 1.8 cm against E. coli and 1.97 cm against S. aureus bacteria. This study result indicated that ZnO nanoparticles have antibacterial activity by producing inhibition against E. coli and S. aureus.

Plant extract-mediated green synthesis of gold nanoparticles (AuNPs) is currently gaining significant interest in the field of nanotechnology. In this study, AuNPs were synthesized using an aqueous extract of Andaliman fruit (Zanthoxylum acanthopodium DC.). The formation of AuNPs was confirmed by observing the color change of the solution from clear to cherry red. The reaction parameters, namely the extract concentration and the ratio of the mixture of the extract with HAuCl4 solution, were optimized for the AuNPs biosynthesis. The gold nanoparticles were characterized using a UV-Vis spectrophotometer, SEM-EDS, and particle size analyzer. The characterization suggested that AuNPs had a maximum wavelength ranging of 540–559 nm, with spherical crystals morphology where the highest component was gold at 36.01% and the size below 100 nm on average. The antioxidant activity of the synthesized AuNPs was determined using the DPPH method. It showed that the highest free radical scavenging activity was 83%, given by 20 ppm AuNPs.

Green synthesized nanomaterials have been widely developed because of their less toxicity, low energy process, environmentally friendly, effective, cheap, and pollution-free. Green synthesis of silver doped titanium dioxide nanoparticles (Ag/TiO2 NPs) was carried out using Mirabilis jalapa plant extract. The plant extract was used as a reducing agent. The functional groups, morphology, and crystalline structure of as-synthesized Ag/TiO2 NPs were investigated by FT-IR, FESEM, and XRD. Analysis by FESEM confirmed that the morphology of Ag/TiO2 NPs is spherical with an average size of ~ 400 nm. Crystallite size for the Ag/TiO2 NPs was calculated by the Scherrer formula dan the average size found to be in the range of 15.72 nm. The result of XRD analysis showing the fcc structure for metallic silver and TiO2 particles in the anatase and rutile phases.

The Centrifugal liquid Membrane (CLM) method, which provides an ultra-thin two-phase liquid membrane system in a rotating glass cell, was successfully applied to Green Synthesis from Polyscias scutellaria (PS) capped gold nanoparticles (AuNPs-PS) using a Mangkokan leaf (Polyscias scutellaria) extract as a reducing agent and stabilizer in the hexane-water system. PS extract in hexane fraction as the organic phase has a UV absorption spectrum at the maximum wavelength, λmax of 220 nm, while the precursor of HAuCl4 solution as an aqueous phase has an λmax of 214 nm. Investigation of AuNPs-PS formation was carried out at various concentrations of Mangkokan leaf extract concentration; i.e., 0.001 0.003; 0.005; 0.007 and 0.009%, while the reaction was carried out at various rotational speeds of 5,000-9,000 rpm. The formation and stability of AuNPs-PS were observed from the phenomenon of surface plasmon resonance (SPR) and absorbance changes as measured by a UV-Vis spectrophotometer. The results of measurements using CLM-Spectrophotometry shows the formation of AuNPs-PS in the hexane-water system at λmax of 534 nm.

Wilt and anthracnose are diseases on chili that cause substantial losses and even crop failure. Control of the diseases is generally carried out using chemical pesticides which are environmentally harmful. Therefore, the development of nanoparticles, such as nanochitosan-Cu, can be an environmentally friendly solution in controlling chili disease. The current technology in developing nanochitosan-Cu is green synthesis, which uses an effective reducing agent but non-toxic for plants and the environment. However, the process requires sonication, which is difficult to be adapted for scale-up production. This research aimed to synthesize and determine the formulation of nanochitosan –Cuusing magnetic stirrer method without sonication, and also to evaluate the antifungal ability of nanochitosan-Cu againstFusarium oxysporum and Colletotrichum capcisi causing wilt and anthracnose disease, respectively. Synthesis of nanochitosan-Cu was carried out at 50°C and 400 rpm of speed. Characterizations of nanochitosan-Cu were analyzed using SEM-EDX and PSA. In vitro antifungal activity test was carried out by food poisoning method.The results showed that the synthesis of nanochitosan-Cu using ionic gelation method can be carried out without sonication process, and produce round shape nanoparticles with 183.7 nm of diameter. The nanochitosan-Cu was effective against F. oxysporum and C. capsici, at a concentration of 100 ppm. It inhibited the growth of F. oxysporum and C. capsici by 100% and 92.38%, respectively.

In this study, the reduced graphene oxide (rGO) synthesized by using lime juice as an environmentally friendly reducing agent and inexpensive cost. The synthesis was carried out by oxidizing graphite with the Hummer method to form graphene oxide (GO) was formed, then the GO was reduced by using lime as the natural reducing agent. X-ray analysis shown a vital diffraction pattern for graphite at 2θ = 26.4°, for graphene oxide appears around 2θ = 10° and 43o, and rGO at 2θ = 23.8°. Furthermore, the infrared spectrum of the three samples showed the peak of the hydroxyl group at 3412 cm-1, which appeared on graphene oxide, but was not observed in rGO. The vibrational mode of carbonyl (C=O) at 1723 cm-1 was also observed with high intensity on graphene oxide. This information showed that GO has a large number of oxygen-containing groups. Then, in the dissolution test shown that the GO was more soluble in polar solvents such as water than ethanol.

Studies of green synthesis of nanoparticles mediated by plants extract is extensively explored and studied in recent time due to eco-friendliness, cost-effectiveness, and use a minimum amount of toxic chemicals in the process of inorganic material synthesis. In this study, the immobilization of silver nanoparticles on the surface of titanium dioxide (TiO2) was carried out using Uncaria gambier Roxb. leaf extract as a silver ion (Ag+) reducing agent. The synthesized Ag/TiO2 nanocomposite was characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and Diffuse Reflectance Spectroscopy (DRS). The formation of silver nanoparticles was confirmed through UV-Vis spectroscopic analysis, which showed a silver surface plasmon resonance (SPR) band at 426 nm. The X-ray diffraction pattern shows that Ag can inhibit the transition of the anatase into rutile phase. The presence of Ag particles in TiO2 can increase the absorption ability from an initial wavelength of 407 nm to 438 nm. Based on the results of Rhodamin B degradation, it can be seen that Ag/TiO2 has a higher photocatalytic activity than bare TiO2 with 99% percent degradation at 120 minutes of irradiation time.

Carbon dots (C-dots) adalah tipe baru dari nanopartikel berpendar yang dapat mudah disintesis dari sumber alami. Sintesis C-dots dari daun bambu telah berhasil dilakukan menggunakan teknik sintesis hijau berbantukan gelombang mikro. Teknik sintesis hijau dilakukan dengan menggunakan air sebagai pelarut non-kimia dan sumber alami. Sintesis dilakukan menggunakan variasi konsentrasi prekursor untuk dipelajari pengaruhnya terhadap sifat fisik dan sifat optiknya. Sifat fisik C-dots menunjukkan warna transparan di bawah cahaya tampak, dan warna hijau di bawah laser UV 405 nm. Sifat optik C-dots dikarakterisasi menggunakan spektrofotometer UV-Vis, dan spektrofotometer dengan sumber eksitasi 405 nm. Konsentrasi prekursor mempengaruhi intensitas eksitasi dan emisi, namun pergeseran Stokes C-dots memiliki kestabilan yang sangat baik dalam larutan berair. Pergeseran Stokes berasal dari keadaan transisi n–π* dari struktur ikatan aromatik C=O pada permukaan C-dots. Kami peroleh C-dots yang berpotensi untuk diaplikasikan sebagai bioimaging seluler in vivo dan in vitro dan biosensing ion logam dan garam. Carbon dots (C-dots) are a new type of fluorescent nanoparticles that can be easily synthesized from natural resources. The synthesis of C-dots from bamboo leaves was successfully carried out using microwave assisted green synthesis techniques. Green synthesis techniques are carried out using water as a non-chemical solvent and natural sources. Synthesis is carried out using variations in the concentration of precursors to be studied for their effects on the physical and optical properties. The physical properties of C-dots show transparent colors under visible light, and green color under the UV 405 nm laser. The optical properties of C-dots were characterized using a UV-Vis spectrophotometer, and a Fluorescence spectrophotometer with an excitation source of 405 nm. Precursor concentrations affect excitation and emission intensity, but Stokes's shift to C-dots has excellent stability in aqueous solutions. Stokes' shift originated from the transition state n-π* from structure of aromatic bond C=O on surface of C-dots. We obtained C-dots which have the potential to be applied as cellular bioimaging in vivo and in vitro and biosensing metal ions and salts.

A simple and efficient synthesis of 2H-indazoles is achieved from 2-primary amines, bromobenzaldehydes and sodium azide through domino condensation, C–N and N–N bond formations, catalyzed by a heterogeneous Cu(II)-Clay catalyst. The recyclable heterogeneous Cu(II)-Clay catalyst exhibited a remarkable activity for the title reaction without any additives. An assortment of structurally diverse 2H-indazoles were prepared in good to excellent yields from easily available starting materials by using this protocol. The Cu(II)-Clay catalyst was characterized by using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Brunauer-Emmett-Teller (BET) techniques.

Gold nanoparticles (AuNPs) have been successfully prepared by green synthesis method using aqueous extract of garlic with the Latin name of Allium sativum L. (ASL) as a reducing and stabilizing agents. Identification of active compounds in aqueous ASL extract was conducted by phytochemical analysis and Fourier transform infrared (FTIR) spectroscopy, while the synthesized AuNPs were characterized using UV-Vis spectrophotometer and transmission electron microscopy-selected area electron diffraction (TEM-SAED). The AuNPs formation was optimized at aqueous ASL extract concentration of 0.05%, HAuCl4 concentration of 2.0×10-4 M, and pH of 3.6. The optimized AuNPs was characterized using TEM, and has a spherical shape with particle size of 15±3 nm. The particles were also stable up until one month. The synthesized AuNPs has been studied its interaction with melamine, and showed the optimum pH of interaction at 3.6.