Monstera deliciosa mediated single step biosynthesis of gold nanoparticles by bottom-up approach and its non-antimicrobial properties.

In this study, we have stated the green biosynthesis of gold nanoparticles (AuNPs) by utilizing the extract of Monstera deliciosa leaves (MDL) as a reducing agent. Biosynthesized flat, thin, and single-crystalline gold nanotriangles obtained through centrifugation are then analyzed by different characterization techniques. The UV - visible absorption spectra of AuNPs exhibited maxima bands in the range of 500-590 nm, indicating a characteristic of AuNPs. XRD analysis revealed the formation of the (111)-oriented face-centered cubic (FCC) phase of AuNPs. ATR-IR spectra showed signatures of stretching vibrations of O-H, C-H, C=C, C=O, C-O, and C-N, accompanied by CH3 rocking vibrations present in functional groups of biomolecules. FESEM images confirmed spherical nanoparticles with an average diameter in the range of 53-66 nm and predominantly triangular morphology of synthesized AuNPs within the size range of 420-800 nm. NMR, GC-MS, and HR-MS studies showed the presence of different biomolecules, including phenols, flavonoids, and antioxidants in MDL extracts, which play a crucial role of both, reducing as well as stabilizing and capping agents to form stable AuNPs by a bottom-up approach. They were then investigated for their antibacterial assay against Gram-positive (S. aureus, B. subtilis) and Gram-negative (E. coli, P. aeruginosa) microorganisms, along with testing of antifungal potential against various fungi (Penicillium sp., Aspergillus flavus, Fusarium oxysporum, Rhizoctonia solani) using the well diffusion method. Here, biosynthesized AuNPs showed non-antimicrobial properties against all four used bacteria and fungi, showing their suitability as a contender for biomedical applications in drug delivery ascribed to their inert and biocompatible nature. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03898-0.

Bioactive properties of ZnO nanoparticles synthesized using Cocos nucifera leaves.

Biosynthesis of zinc oxide nanoparticles has been reported using Cocos nucifera leaf (CNL) extract along with estimation of their antimicrobial potential before and after calcination using different micro-organisms. UV-visible spectra of ZnO nanoparticles showed absorption maxima at 383 nm and 363 nm, respectively, with 3.237 eV and 3.416 eV, respectively, as the corresponding band gap energies. FESEM and TEM images showed spherical morphologies of ZnO nanoparticles within the size range 109-215 nm. XRD analysis confirmed the formation of hexagonal wurtzite structures. ATR-IR spectra revealed the presence of stretching vibrations of N-H, O-H, C=C, C=O and NH2 groups along with C-H and N-H deformation involving biomolecules from CNL extract responsible for reduction and stabilization of ZnO nanoparticles. Uncalcinated ZnO nanoparticles displayed antibacterial activities only against S. aureus and P. aeruginosa whereas calcinated ZnO nanoparticles did not show antibacterial activities against E. coli, S. aureus, P. aeruginosa and B. subtilis. ZnO nanoparticles were not active against Penicillium spp., Fusarium oxysporum, Aspergillus flavus, Rhizoctonia solani as well as HCT-116 cancer cells before as well as after calcination. Antimicrobial nature and biocompatibility of ZnO nanoparticles were influenced by different parameters of the nanoparticles along with micro-organisms and the human cells. Non-antimicrobial properties of ZnO nanoparticles can be treated as a pre-requisite for its biocompatibility due to its inert nature. These ZnO nanoparticles can serve a dual purpose by facilitating use as antibacterial agent against susceptible micro-organisms as well as a biocompatible carrier molecule in drug delivery applications. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-022-03110-9.

Non-antimicrobial and Non-anticancer Properties of ZnO Nanoparticles Biosynthesized Using Different Plant Parts of Bixa orellana.

As traditional cancer therapy is toxic to both normal and cancer cells, there is a need for newer approaches to specifically target cancer cells. ZnO nanoparticles can be promising due their biocompatible nature. However, ZnO nanoparticles have also shown cytotoxicity against mammalian cells in some cases, because of which there is a need for newer synthesis approaches for biocompatible ZnO nanoparticles to be used as carrier molecules in drug delivery applications. Here, we report the biosynthesis of ZnO nanoparticles using different plant parts (leaf, seed, and seed coat) of Bixa orellana followed by different characterizations. The UV-visible spectra of ZnO showed absorption maxima at 341 and 353 nm, 378 and 373 nm, and 327 and 337 nm, respectively, before and after calcination corresponding to the band gap energy of 3.636 and 3.513 eV, 3.280 and 3.324 eV, and 3.792 and 3.679 eV for L-ZnO, S-ZnO, and Sc-ZnO, respectively. X-ray diffraction analysis confirmed the formation of hexagonal wurtzite structures. Attenuated total reflectance infrared spectra revealed the presence of stretching vibrations of C-C, C=C, C=O, and NH3 + groups along with C-H deformation involving biomolecules from extracts responsible for reduction and stabilization of nanoparticles. Field emission scanning electron microscopy and transmission electron microscopy images showed spherical and almond-like morphologies of L-ZnO and Sc-ZnO with spherical morphologies, whereas S-ZnO showed almond-like morphologies. The presence of antibacterial activity was observed in L-ZnO against Staphylococcus aureus and Bacillus subtilis, in S-ZnO nanoparticles only against Escherichia coli, and in Sc-ZnO only against Staphylococcus aureus. Uncalcinated ZnO nanoparticles showed weak antibacterial activities, whereas calcinated ZnO nanoparticles showed a non-antibacterial nature. The antifungal activity against different fungi (Penicillium sp., Aspergillus flavus, Fusarium oxysporum, and Rhizoctonia solani) and cytotoxicity against HCT-116 cancer cells were not observed before and after calcination in all three ZnO nanoparticles. The antimicrobial nature and biocompatibility of ZnO nanoparticles were influenced by different parameters of the nanoparticles along with microorganisms and the human cells. Non-antimicrobial properties of ZnO nanoparticles can be treated as a pre-requisite for its biocompatibility due to its inert nature. Thus, biosynthesized ZnO nanoparticles showed a nontoxic nature, which can be exploited as promising alternatives in biomedical applications.

Use of nanotechnology in combating coronavirus.

Recent COVID-19 pandemic situation caused due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affected global health as well as economics. There is global attention on prevention, diagnosis as well as treatment of COVID-19 infection which would help in easing the current situation. The use of nanotechnology and nanomedicine has been considered to be promising due to its excellent potential in managing various medical issues such as viruses which is a major threat. Nanoparticles have shown great potential in various biomedical applications and can prove to be of great use in antiviral therapy, especially over other conventional antiviral agents. This review focusses on the pathophysiology of SARS-CoV-2 and the progression of the COVID-19 disease followed by currently available treatments for the same. Use of nanotechnology has been elaborated by exploiting various nanoparticles like metal and metal oxide nanoparticles, carbon-based nanoparticles, quantum dots, polymeric nanoparticles as well as lipid-based nanoparticles along with its mechanism of action against viruses which can prove to be beneficial in COVID-19 therapeutics. However, it needs to be considered that use of these nanotechnology-based approaches in COVID-19 therapeutics only aids the human immunity in fighting the infection. The main function is performed by the immune system in combatting any infection.

A Review on Green Synthesis and Applications of Iron Oxide Nanoparticles.

Bio-fabrication of iron oxide nanoparticles by using different sources of plants, plant parts and microbial cells have become a great topic of interest nowadays due to its eco-friendly nature. The stabilizing and capping agents in biological sources are biocompatible, stable and non-toxic which make its use beneficial for various biomedical applications. The bacteria are able to utilize metal ions and convert them into their respective nanoparticles by secreting different biomolecules. The plants and plant parts contain different types of phytochemicals which play a key role in synthesis and bio-fabrication of nanoparticles. Iron oxide nanoparticles are known to have various applications in the fields of medicine, environment etc. This review summarizes the applications of iron oxide nanoparticles as antimicrobial agent, drug delivery agent, material for removal of heavy metals and dyes from aqueous system etc. Due to these wide applications of iron oxide nanoparticles its demand in various fields is increasing considerably. This review describes different approaches which are used for biosynthesis of iron oxide nanoparticles and their applications. The review also summarizes about the surface modification strategies of iron oxide nanoparticles by using different polymers, polyelectrolytes which can be used for in-vivo applications.

Non-Antibacterial and Antibacterial ZnO Nanoparticles Composed of Different Surfactants.

Zinc oxide nanoparticles were synthesized using different surfactants such as SDS, CTAB, Triton X-100, PVP K-30 and ethylene glycol. ZnO NPs were tested for antibacterial activity before and after calcination against different micro-organisms like E. coli and P. aeruginosa (Gram negative) as well as S. aureus and B. subtilis (Gram positive). Antibacterial activity was observed in SDScapped ZnO NPs only against B. subtilis. Antibacterial activity of ZnO-capped SDS was tested in a concentration range 0.625-10 mg/mL. Increased antibacterial activity was observed before calcination as compared to after calcination. Minimum concentration at which uncalcinated as well as calcinated SDS-capped ZnO NPs show antibacterial activity is 2.5 mg/mL and 5 mg/mL respectively. Non-antibacterial nature of ZnO NPs highlights its further use in drug delivery due to its inert nature, enhanced efficacy in association with therapeutic drugs as well as easy disposal.

Antibacterial Activities of Biosynthesized ZnO Nanoparticles Using Leaf and Fruit Extracts of Neolamarckia cadamba.

Zinc oxide nanoparticles have been biosynthesized with the help of Neolamarckia cadamba leaf and fruit extracts. ZnO nanoparticles were tested for antibacterial activity before and after calcination against Gram positive (Staphylococcus aureus, Bacillus subtilis) as well as Gram negative micro-organisms (Escherichia coli, Pseudomonas aeruginosa) within the concentration range 0.625-10 mg/mL with the help of well diffusion technique. Higher antibacterial potential has been observed in ZnO nanoparticles synthesized using leaf extract in comparison with those synthesized using fruit extract. Increased antibacterial activity was observed before calcination as compared to after calcination. ZnO synthesized using leaf extract were observed to show significant antibacterial potential against E. coli, S. aureus along with P. aeruginosa before calcination as well as against E. coli after calcination. Similarly, ZnO nanoparticles synthesized using fruit extract exhibited antibacterial activity against E. coli and P. aeruginosa before calcination and against E. coli after calcination. Both the ZnO nanoparticles before and after calcination did not show any antibacterial activity against B. subtilis. Thus, ZnO nanoparticles can serve a dual purpose by its application as an antibacterial agent against susceptible micro-organisms as well as biocompatible carrier system for drug delivery applications in case of non-antibacterial properties by virtue of its inertness as well as easy disposal.

Uptake of Methylene Blue from Aqueous Solution by Naturally Grown Daedalea africana and Phellinus adamantinus Fungi.

Herein, Daedalea africana and Phellinus adamantinus were evaluated for the uptake of the methylene blue (MB) dye. Various factors such as pH range, time of exposure, dye concentration, adsorbed quantity, etc. have been studied for the uptake. Adsorption isotherms investigated in this study include the Langmuir and Freundlich isotherms. The Langmuir isotherm has been long known to be the best fit in the process of adsorption. The maximum monolayer adsorption capacity for D. africana was reported to be 0.5210 mol/kg, and it is 1.8387 mol/kg for P. adamantinus at 298 K. The n values 0.8748 and 0.9524 obtained indicate that the dye is favorably adsorbed on both adsorbents. Kinetics data analysis has shown that methylene blue adsorbed on the fungus showed pseudo-second-order chemisorption and film as well as intra particle diffusion. These results reveal that the abovementioned fungi can be used as good sources for the uptake of the MB dye.

Synthesis and Antimicrobial Properties of Zinc Oxide Nanoparticles.

With increase in incidence of multidrug resistant pathogens, there is a demand to adapt newer approaches in order to combat these diseases as traditional therapy is insufficient for their treatment. Use of nanotechnology provides a promising alternative as antimicrobial agents as against traditional antibiotics. Metal oxides have been exploited for a long times for their antimicrobial properties. Zinc oxide nanoparticles (ZnO NPs) are preferred over other metal oxide nanoparticles because of their bio-compatible nature and excellent antibacterial potentials. The basic mechanism of bactericidal nature of ZnO nanoparticles includes physical contact between ZnO nanoparticles and the bacterial cell wall, generation of reactive oxygen species (ROS) as well as free radicals and release of Zn2+ ions. This review focuses on different synthesis methods of ZnO nanoparticles, various analytical techniques frequently used for testing antibacterial properties, mechanism explaining antibacterial nature of ZnO nanoparticles as well as different factors affecting the antibacterial properties.

A Review on Antimicrobial Properties of Metal Nanoparticles.

The field of nanotechnology elaborates the synthesis, characterization as well as application of nanomaterials. Applications of nanoparticles in various fields have interested scientists since decades due to its unique properties. Combination of pharmacology with nanotechnology has helped in development of newer antimicrobial agents in order to control the ever increasing multidrug resistant micro-organisms. Properties of metal and metal oxide nanoparticles like silver, gold, titanium dioxide as well as magnesium oxide as antimicrobial agents are very well known. This review elaborates synthesis methods and antimicrobial mechanisms of various metal as well as metal oxide nanoparticles for better understanding in order to utilize their potentials in various biomedical applications.

Non-antibacterial as well as non-anticancer activity of flower extract and its biogenous silver nanoparticles.

Silver nanoparticles were synthesized by using the white flower extract of Albizia lebbeck as a source of reducing and capping agents. A. lebbeck white flower extract and silver nanoparticles were checked for their antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeroginosa and Ba cillus subtilis by using Mueller Hinton agar, nutrient agar and Luria Bertani agar using the well diffusion method. The synthesized silver nanoparticles did not show antibacterial activity at lower (0.1-0.4 mg ml-1) or higher (0.5-2.5 mg ml-1) concentrations against any of the four organisms on either of the media, even though silver nanoparticles have been well known to show antibacterial activity even at lower concentrations. The non-antibacterial properties of the synthesized silver nanoparticles against all four bacteria were confirmed using viability counting. With this unique non-antibacterial property of biogenous silver nanoparticles observed in this study, it can be stated that case by case evaluation of every synthesized silver nanoparticle needs to be done as there are multiple factors influencing their properties. Anticancer activity of these nanoparticles at different concentrations against A549 cancer cells did not show any significant decrease in cell viability highlighting its biocompatible nature. Thus, these silver nanoparticles can be a best suited candidate for drug delivery.

Synthesis of Mesoporous Nanocrystalline Zirconia by Surfactant-Assisted Hydrothermal Approach.

In this paper, we have reported the chemical synthesis of thermally stable mesoporous nanocrystalline zirconia with high surface area using a surfactant-assisted hydrothermal approach. We have employed different type of surfactants such as CTAB, SDS and Triton X-100 in our synthesis. The synthesized nanocrystalline zirconia multistructures exhibit various morphologies such as rod, mortar-pestle with different particle sizes. We have characterized the zirconia multistructures by X-ray diffraction study, Field emission scanning electron microscopy, Attenuated total refection infrared spectroscopy, UV-Vis spectroscopy and photoluminescence spectroscopy. The thermal stability of as synthesized zirconia multistructures was studied by thermo gravimetric analysis, which shows the high thermal stability of nanocrystalline zirconia around 900 °C temperature.

Centrifuge Controlled Shape Tuning of Biosynthesized Gold Nanoparticles Obtained from Plumbago zeylanica Leaf Extract.

Development of cost-efficient and eco-friendly biogenic synthetic protocols for the green synthesis of biocompatible metal nanoparticles has become popular among researchers in recent years. The biogenic synthesis of these nanoparticles and their potential biomedical applications introduces the concept of nanobiotechnology, which has become the latest fascinating area of research. The lower cost and lesser side effects as compare to chemical methods of synthesis are the main advantages of biosynthesis. In the present investigation, aqueous leaf extract of Plumbago zeylanica had been used to synthesize anisotropic gold nanoparticles. The as-synthesized gold nanoparticles were centrifuged at 5000 and 10000 rpm and compared both pellets using UV-visible spectroscopy, XRD, FTIR and TEM techniques. We have studied here the effect of speed of centrifugation on the yield, shape, size as well as size distribution of as synthesized gold nanoparticles.

Solar Photocatalytic Degradation of Methylene Blue by ZnO Nanoparticles.

The scalable and economical synthesis approach of ZnO has always been demanded, since it is very useful material in the degradation of hazardous dyes. Herein, a scalable synthesis approach for ZnO nanoparticles by precipitating the precursors such as zinc sulphate heptahydrate and ammonium hydroxide has been proposed. Calcinations at suitable temperatures can improve crystalline nature of materials. Therefore as-synthesized ZnO nanoparticles were calcinated at different temperatures 400 °C, 650 °C, 900 °C, 1150 °C, and subsequently their physical and morphological properties were characterized. The TEM analysis revealed the morphology, whereas XRD and SAED confirmed the purity and crystalline nature of ZnO. Moreover, photo catalytic degradation/adsorption results for methylene blue dye of lower (2.5 ppm) and higher concentrations (5 ppm) in the presence and absence of sunlight and ZnO nanoparticles are also reported. Addition of ZnO nanoparticles to methylene blue resulted in enhanced rate of photo degradation in the presence of sunlight. The complete photodegradation of 2.5 and 5 ppm methylene blue in sunlight occurred in 90 min and 165 min, respectively in presence of ZnO nanoparticles. In general many photocatalytic degradation studies had been reported using an artificial light source; however in the present work direct sunlight has been utilized.

Edible Inonotus dryadeus Fungi with Quick Separation of Water Pollutant Oils and Methylene Blue Dye.

Herein, dry Inonotus dryadeus (DID) fungi is reported as a rapid separator of engine oil, used engine oil, and lambda cyhalothrin pesticide with adsorption capacities up to 7.15, 8.40, and 5.75 times mass of DID, respectively. The high adsorption of methylene blue dye at equilibrium (137 mg/g) is significantly higher than recently reported iron amended activated carbon (10.30 mg/g), tea fruit activated carbon (21.37 mg/g), and titanate nanotubes (94.15 mg/g). This study with plausible mechanisms authenticates an economically viable model for water body cleaning technology and oil, using oil-adsorbed cakes of DID as a source of energy.

Synthesis, characterization, photophysical properties of a novel organic photoswitchable dyad in its pristine and hybrid nanocomposite forms.

In the present paper the method of synthesis and characterization of a novel organic dyad, 3-(1-Methoxy-3,4-dihydro-naphthalyn-2-yl-)-1-p-chlorophenyl propenone, have been reported. In this paper our main thrust is to fabricate new hybrid nanocomposites by combining the organic dyad with different noble metals, semiconductor nanoparticle and noble metal-semiconductor core/shell nanocomposites. In this organic dyad, donor part is 1-Methoxy-3, 4-dihydro-naphthalen-2-carboxaldehyde with the acceptor p-chloroacetophenone. We have carried out steady state and time-resolved spectroscopic measurements on the dyad and its hybrid nanocomposite systems. Some quantum chemical calculations have also been done using Gaussian 03 software to support the experimental findings by theoretical point of view. Both from the theoretical predictions and NMR studies it reveals that in the ground state only extended (E-type or trans-type) conformation of the dyad exists whereas on photoexcitation these elongated conformers are converted into folded forms (Z- or cis-type) of the dyad, showing its photoswitchable character. Time resolved fluorescence spectroscopic (fluorescence lifetime by TCSPC method) measurements demonstrate that in chloroform medium all the organic-inorganic hybrid nanocomposites, studied in the present investigation, possess larger amount of extended conformers relative to folded ones, even in the excited singlet state. This indicates the possibility of slower energy destructive charge recombination rates relative to the rate processes associate with charge-separation within the dyad. It was found that in CHCl3 medium, the computed charge separation rate was found to be approximately 10(8) s(-1) for the dyad alone and other hybrid nanocomposite systems. The rate is found to be faster than the energy wasting charge recombination rate approximately 10(2)-10(1) s(-1), as observed from the transient absorption measurements for the corresponding hybrid systems. It indicates the conformational geometry has a great effect on the charge-separation and recombination rate processes. The suitability for the construction of efficient light energy conversion devices especially with Ag-Dyad nanocomposite of all the systems studied here is hinted from the observed long ion-pair lifetime.

Morphology and polymorphic phase changes of calcium carbonate micro/nanocrystals using fruit extracts.

This study reveals the morphology and polymorphic phase changes of calcium carbonate crystals into a mixture of calcite and aragonite micro/nanocrystals of interesting morphology at room temperature by a simple reaction with fruit extracts of Tamarindus indica and Emblica officinalis respectively by mixing CaCO3 solutions with their corresponding extracts. The control experiments were carried out to establish the plausible role of tartaric acid from Tamarindus indica and ascorbic acid from Emblica officinalis in this regard. The quantitative determination of CaCO3 phases was done based on the use of intensities obtained from corresponding XRD spectrum. The molar % of aragonite was found to be more in case of TA and AA rather than TI and EO respectively, however the calcite was observed to be the predominant phase in all four reactions. Interestingly, the TI changes the rhombohedral morphology of calcite to elongated rods, whereas EO induces a great polymorphic phase change.

Biosynthesis of gold and silver nanoparticles using Emblica Officinalis fruit extract, their phase transfer and transmetallation in an organic solution.

The design, synthesis and characterization of biologically synthesized nanomaterials have become an area of significant interest. In this paper, we report the extracellular synthesis of gold and silver nanoparticles using Emblica Officinalis (amla, Indian Gooseberry) fruit extract as the reducing agent to synthesize Ag and Au nanoparticles, their subsequent phase transfer to an organic solution and the transmetallation reaction of hydrophobized silver nanoparticles with hydrophobized chloroaurate ions. On treating aqueous silver sulfate and chloroauric acid solutions with Emblica Officinalis fruit extract, rapid reduction of the silver and chloroaurate ions is observed leading to the formation of highly stable silver and gold nanoparticles in solution. Transmission Electron Microscopy analysis of the silver and gold nanoparticles indicated that they ranged in size from 10 to 20 nm and 15 to 25 nm respectively. Ag and Au nanoparticles thus synthesized were then phase transferred into an organic solution using a cationic surfactant octadecylamine. Transmetallation reaction between hydrophobized silver nanoparticles and hydrophobized chloroaurate ions in chloroform resulted in the formation of gold nanoparticles.

Biological synthesis of triangular gold nanoprisms.

The optoelectronic and physicochemical properties of nanoscale matter are a strong function of particle size. Nanoparticle shape also contributes significantly to modulating their electronic properties. Several shapes ranging from rods to wires to plates to teardrop structures may be obtained by chemical methods; triangular nanoparticles have been synthesized by using a seeded growth process. Here, we report the discovery that the extract from the lemongrass plant, when reacted with aqueous chloroaurate ions, yields a high percentage of thin, flat, single-crystalline gold nanotriangles. The nanotriangles seem to grow by a process involving rapid reduction, assembly and room-temperature sintering of 'liquid-like' spherical gold nanoparticles. The anisotropy in nanoparticle shape results in large near-infrared absorption by the particles, and highly anisotropic electron transport in films of the nanotriangles.