Eco-friendly biosynthesis metallic silver nanoparticles using Aegle marmelos (Indian bael) and its clinical and environmental applications

Green Synthesis, Characterization and Application of Silver Nanoparticles Using Bioflocculant: A Review

Nanotechnology has emerged as an effective means of removing contaminants from water. Traditional techniques for producing nanoparticles, such as physical methods (condensation and evaporation) and chemical methods (oxidation and reduction), have demonstrated high efficiency. However, these methods come with certain drawbacks, including the significant energy requirement and the use of costly and hazardous chemicals that may cause nanoparticles to adhere to surfaces. To address these limitations, researchers are actively developing alternative procedures that are cost-effective, environmentally safe, and user-friendly. One promising approach involves biological synthesis, which utilizes plants or microorganisms as reducing and capping agents. This review discusses various methods of nanoparticle synthesis, with a focus on biological synthesis using naturally occurring bioflocculants from microorganisms. Bioflocculants offer several advantages, including harmlessness, biodegradability, and minimal secondary pollution. Furthermore, the review covers the characterization of synthesized nanoparticles, their antimicrobial activity, and cytotoxicity. Additionally, it explores the utilization of these NPs in water purification and dye removal processes.

Eco-friendly green synthesis of AgNPs from Elaeocarpus serratus fruit extract: potential to antibacterial, antioxidant, cytotoxic effects of colon cancerous cells (HT-29) and its toxicity assessments of marine microcrustacean Artemia nauplii

BACKGROUND

The present work demonstrated the green synthesis and characterization of silver nanoparticles (AgNPs) utilizing Elaeocarpus serratus fruit extract. The study examined the effectiveness of phytocompounds in fruit extract in reducing Ag+ to Ag° ions.

METHODS

The water-soluble biobased substance production from silver ions to AgNPs in 45 min at room temperature. Surface plasmon resonance (SPR) peak was seen in the UV-visible absorption spectrum of the biologically altered response mixture. Examination with X-ray diffraction (XRD) showed that AgNPs are strong and have a face-centered cubic shape. Scanning electron microscope (SEM) investigation proved the production of AgNPs in a cuboidal shape.

RESULTS

The AgNPs demonstrated remarkable antibacterial activity and a potent capacity to neutralize DPPH (2,2-Diphenyl-1-picrylhydrazyl) radicals. The highest growth inhibition was found for E. serratus against S. dysenteriae (18.5 ± 1.0 mm) and S. aureus (18 ± 1.2 mm). These nanoparticles exhibited robust antiradical efficacy even at low concentrations. The AgNPs additionally exhibited cytotoxic effects on (HT-29) human colon adenocarcinoma cancer cells. The MTT assay (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) indicated an inhibitory concentration (IC50) value of 49.1 ± 2.33 µg/mL for AgNPs, contrasting with the untreated cells of the negative control. The biotoxicity assessment using A. salina displayed mortality rates ranging from 8 to 69.33%, attributable to the E. serratus synthesized AgNPs.

CONCLUSIONS

In our results concluded that simply first-hand information on that E. serattus fruit extract synthesized AgNPs were efficiently synthesized without the addition of any hazardous substances, and that they may be a strong antibacterial, antioxidant, and potential cytotoxic effects for the treatment of colon carcinoma cell lines.

Critical Evaluation of Green Synthesized Silver Nanoparticles-Kaempferol for Antibacterial Activity Against Methicillin-Resistant Staphylococcus aureus

Introduction

This study aimed to characterize silver nanoparticles-kaempferol (AgNP-K) and its antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA). Green synthesis method was used to synthesize AgNP-K under the influence of temperature and different ratios of silver nitrate (AgNO3 and kaempferol).

Methods

AgNP-K 1:1 was synthesized with 1 mM kaempferol, whereas AgNP-K 1:2 with 2 mM kaempferol. The characterization of AgNP-K 1:1 and AgNP-K 1:2 was performed using UV-visible spectroscopy (UV-Vis), Zetasizer, transmission electron microscopy (TEM), scanning electron microscopy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The antibacterial activities of five samples (AgNP-K 1:1, AgNP-K 1:2, commercial AgNPs, kaempferol, and vancomycin) at different concentrations (1.25, 2.5, 5, and 10 mg/mL) against MRSA were determined via disc diffusion assay (DDA), minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) assay, and time-kill assay.

Results

The presence of a dark brown colour in the solution indicated the formation of AgNP-K. The UV-visible absorption spectrum of the synthesized AgNP-K exhibited a broad peak at 447 nm. TEM, Zetasizer, and SEM-EDX results showed that the morphology and size of AgNP-K were nearly spherical in shape with 16.963 ± 6.0465 nm in size. XRD analysis confirmed that AgNP-K had a crystalline phase structure, while FTIR showed the absence of (-OH) group, indicating that kaempferol was successfully incorporated with silver. In DDA analysis, AgNP-K showed the largest inhibition zone (16.67 ± 1.19 mm) against MRSA as compared to kaempferol and commercial AgNPs. The MIC and MBC values for AgNP-K against MRSA were 1.25 and 2.50 mg/mL, respectively. The time-kill assay results showed that AgNP-K displayed bacteriostatic activity against MRSA. AgNP-K exhibited better antibacterial activity against MRSA when compared to commercial AgNPs or kaempferol alone.

Green synthesis-assisted copper nanoparticles using Aegle marmelos leaves extract: physical, optical, and antimicrobial properties

In the present report, Aegle marmelos leaf powder was used to synthesize copper nanoparticles (CuNPs) using a simple and cost-effective method. A. marmelos leaves have various medicinal uses including for the treatment of diarrhoea, constipation, diabetes, cholera, skin diseases, earache, blood purification, heart problems, and so on. The plant biomolecules induce the reduction of Cu2+ ions to CuNPs and also act as a capping and stabilizing agent. The formation of CuNPs was confirmed using photoluminescence (PL) excitation and emission spectra on a Shimadzu RF-5301 PC spectrofluorophotometer and the absorbance spectra of a UV-visible spectrophotometer at different stages during the synthesis process. In addition, other properties of synthesized CuNPs were also investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy techniques. The average size of the synthesized CuNPs was in the range 20-40 nm. Furthermore, the synthesized NPs were also considered for an antimicrobial study against Gram-positive Staphylococcus aureus and Proteus, and Gram-negative Escherichia coli and Salmonella spp. using the agar well diffusion method. The zone of inhibition against the Gram-positive bacteria was greater than the zone of inhibition against the Gram-negative bacteria. These investigation results suggest that synthesized NPs are promising nanomaterials for use as antimicrobial agents.

Polyaniline-Coated Surface-Modified Ag/PANI Nanostructures for Antibacterial and Colorimetric Melamine Sensing in Milk Samples

Silver nanoparticles (Ag NPs) are trusted candidates for many biological characteristics and applications due to their low toxicity and biologically benign nature. Due to inherited bactericidal characteristics, these Ag NPs are surface-modified with polyaniline (PANI), an organic polymer that has distinctive functional groups which have their role in inducing ligand properties. The Ag/PANI nanostructures were synthesized by the solution method, and their antibacterial and sensor properties were evaluated. Maximum inhibitory performance was seen with modified Ag NPs compared with their pure counterparts. The Ag/PANI nanostructures (0.1 μg) were incubated with E. coli bacteria, and almost complete inhibition was seen after 6 h. Furthermore, the colorimetric melamine detection assay by Ag/PANI as a biosensor also yielded efficient and reproducible results up to a 0.1 μM melamine concentration in daily-life milk samples. The chromogenic shift in color along with spectral validation through UV-vis spectroscopy and FTIR spectroscopy proves the credibility of this sensing method. Thus, high reproducibility and efficiency make these Ag/PANI nanostructures practical candidates for food engineering and biological properties.

Green Synthesis of Silver Nanoparticles Using Aerial Part Extract of the Anthemis pseudocotula Boiss. Plant and Their Biological Activity

Green syntheses of metallic nanoparticles using plant extracts as effective sources of reductants and stabilizers have attracted decent popularity due to their non-toxicity, environmental friendliness and rapid nature. The current study demonstrates the ecofriendly, facile and inexpensive synthesis of silver nanoparticles (AP-AgNPs) using the extract of aerial parts of the Anthemis pseudocotula Boiss. plant (AP). Herein, the aerial parts extract of AP performed a twin role of a reducing as well as a stabilizing agent. The green synthesized AP-AgNPs were characterized by several techniques such as XRD, UV-Vis, FT-IR, TEM, SEM and EDX. Furthermore, the antimicrobial and antibiofilm activity of as-prepared AP-AgNPs were examined by a standard two-fold microbroth dilution method and tissue culture plate methods, respectively, against several Gram-negative and Gram-positive bacterial strains and fungal species such as Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), multidrug-resistant Pseudomonas aeruginosa (MDR-PA) and Acinetobacter baumannii (MDR-AB), methicillin-resistant S. aureus (MRSA) and Candida albicans (C. albicans) strains. The antimicrobial activity results clearly indicated that the Gram-negative bacteria MDR-PA was most affected by AgNPs as compared to other Gram-negative and Gram-positive bacteria and fungi C. albicans. Whereas, in the case of antibiofilm activity, it has been found that AgNPs at 0.039 mg/mL, inhibit biofilms formation of Gram-negative bacteria i.e., MDR-PA, E. coli, and MDR-AB by 78.98 ± 1.12, 65.77 ± 1.05 and 66.94 ± 1.35%, respectively. On the other hand, at the same dose (i.e., 0.039 mg/mL), AP-AgNPs inhibits biofilm formation of Gram-positive bacteria i.e., MRSA, S. aureus and fungi C. albicans by 67.81 ± 0.99, 54.61 ± 1.11 and 56.22 ± 1.06%, respectively. The present work indicates the efficiency of green synthesized AP-AgNPs as good antimicrobial and antibiofilm agents against selected bacterial and fungal species.

Biologically Synthesized Silver Nanoparticles and Their Diverse Applications

Nanotechnology has become the most effective and rapidly developing field in the area of material science, and silver nanoparticles (AgNPs) are of leading interest because of their smaller size, larger surface area, and multiple applications. The use of plant sources as reducing agents in the fabrication of silver nanoparticles is most attractive due to the cheaper and less time-consuming process for synthesis. Furthermore, the tremendous attention of AgNPs in scientific fields is due to their multiple biomedical applications such as antibacterial, anticancer, and anti-inflammatory activities, and they could be used for clean environment applications. In this review, we briefly describe the types of nanoparticle syntheses and various applications of AgNPs, including antibacterial, anticancer, and larvicidal applications and photocatalytic dye degradation. It will be helpful to the extent of a better understanding of the studies of biological synthesis of AgNPs and their multiple uses.

Enhanced photocatalytic activity of novel Canthium coromandelicum leaves based copper oxide nanoparticles for the degradation of textile dyes

The present study focused to synthesize the copper oxide nanoparticles (CuONPs) using novel Canthium coromandelicum leaves in a cost-effective, easy, and sustainable approach. The obtained Canthium coromandelicum-copper oxide nanoparticles (CC-CuONPs) were characterized using UV-Visible spectroscopy, FT-IR analysis, FESEM, HR-TEM imaging, and XRD study. The XRD pattern verified the development of crystalline CC-CuONPs with an average size of 33 nm. The biosynthesized CC-CuONPs were roughly spherical, according to HR-TEM and FESEM analyses. FT-IR research verified the existence of functional groups involved in CC-CuONPs production. Cu and O₂ have high-energy signals of 78.32% and 12.78%, respectively, according to data from EDX. The photocatalytic evaluation showed that synthesized CC-CuONPs have the efficiency of degrading methylene blue (MB) and methyl orange (MO) by 91.32%, 89.35% respectively. The findings showed that biosynthesized CC-CuONPs might effectively remove contaminants in an environmentally acceptable manner.

Adsorptive removal of AB113 dye using green synthesized hydroxyapatite/magnetite nanocomposite

In the present study, magnetite nanoparticles (Fe₃O₄NPs) synthesized using Thunbergia grandiflora leaf extract as a reducing agent were doped with hydroxyapatite sourced from waste bivalve clamshells to produce hydroxyapatite/magnetite nanocomposite (HA/Fe₃O₄NPs). The magnetic nanocomposite was examined using several characterization techniques. The results of XRD and FESEM, analysis showed HA/Fe₃O₄NPs have a crystalline phase and irregular spherical particles respectively. EDAX and FTIR confirmed the presence of specific elements and functional groups of both iron oxide and hydroxyapatite nanoparticles respectively. The surface area and superparamagnetic property of the composite were determined by BET and VSM analysis. Central Composite Design (CCD) was used to optimize the adsorption process to remove of AB113 from aqueous solutions. The optimal adsorption efficiency was found out to be 94.38% at pH 8, AB113 dye concentration 54 ppm, HA/Fe₃O₄NPs dose 84 mg, and an agitation speed of 174 rpm. The monolayer Langmuir isotherm was the best model with a sorption capacity of 109.98 mg/g which was higher than the reported values. The pseudo-second-order kinetic model displayed a good fit with an R² = 0.99. Thermodynamic parameters were assessed which confirmed the exothermic adsorption process. Therefore, the synthesized magnetic nanocomposite can be employed as a novel nanoadsorbent for the removal of anionic dyes from waste effluents.

Nano Ag@bioactive microspheres from marine sponge Clathria frondifera: Fabrication, fortification, characterization, anticancer and antibacterial potential evaluation

Bioresources are attaining much importance in the discovery of drugs and delivering agents. In particular, marine sponges are of great interest due to their metabolites production for the survival in risky environment. The incorporation of silver nanoparticles with marine sponge derived metabolites was reported for the first time. In this work, a facile material has been generated of great efficacy in solving environmental and health issues, as a recipe of silver and marine sponge Clathria frondifera, named as Ag Fortified Sponge spheres (AFS). AFS spheres were successfully synthesized after method optimization, using the various extracts of marine sponge Clathria frondifera as effective reducing agent in Ag (I) to Ag (0) reduction. Bioactive material from marine sponge and AgNP from the reduction of AgNO₃ solution stablishing one another and thus AFS spheres were attaining long lifetime along with enhanced antimicrobial activity. The characterization of synthesized AFS and other AgNPs (1-4) has done using FT-IR, PXRD, FESEM, TEM, and UV-vis data. The presence of functional groups such as, Ag-O, and Ag-C stretching bonds in the AFS compounds indicated that it is composed of silver oxides and organo-silver, respectively. The synthesized Ag NPs were found to be spherical like structure with an average size of ∼20 nm. The cytotoxic response of AFS was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and morphological changes. AFS are exact spherical, micro sized and effective in inhibiting the growth of both gram positive and gram-negative bacteria. Anticancer studies were also carried out and ensued with excellent activity in the HELA cells with potential application in the medical industry.