Towards plant-mediated chemistry – Au nanoparticles obtained using aqueous extract of Rosa damascena and their biological activity in vitro
Graphical abstract
Eco-friendly, efficient, and controlled synthesis of gold nanoparticles with application of the aqueous extract of Rosa Damascena (Au@RD NPs) resulted in the stable colloid exhibiting selective cytotoxicity towards acute promyelocytic leukemia (HL60) and human lung adenocarcinoma (A549) over peripheral blood mononuclear lymphocytes (PBML) in vitro.
Introduction
Green chemistry-based synthesis of metal nanoparticles (NPs) is becoming now an increasingly popular eco-friendly method, even instead of chemical synthesis. In particular, plant extracts as reducing and stabilizing agents are progressively used to synthesize metal NPs [[1], [2], [3], [4], [5]]. The interest in their application is great due to the relative ease of synthesis, good control of sizes and shapes, optical characteristics, and high biocompatibility of the resulting NPs.
Gold nanostructures are of a great interest for scientific research because of their wide applications in photonics, electronics, catalysis, optical sensing and imaging, and drug delivery [[6], [7], [8]]. These remarkable applications are built upon the surface plasmonic resonance (SPR) phenomenon that originates from the collective oscillation of conduction electrons relative to the lattice of gold ions [9]. The physicochemical and biological characteristics of Au nanostructures varies as a function of their size, shape, hollowness/porosity, and other properties. Variety of different shapes including nanospheres, nanorods, nanoshells, and nanocages is possible to obtain and various synthetic strategies have recently been proposed in the literature and successfully implemented in laboratories [1,4,[10], [11], [12]]. Importantly, apart from the above-mentioned hallmarks stability and reactivity can also be nowadays precisely controlled [13]. Based on various in vitro studies it is well-documented that overall toxicity exhibited by anisotropic Au NPs can be derived from capping agents or ligands used in their synthesis [12]. However, this is primarily the case of syntheses using toxic organic reagents as capping, reducing and/or stabilizers agents. In such cases, there is concern about inaccurate purification of the samples in the post-treatment or during dialysis exchanging surface ligands. Thus, the remarkable SPR properties together with biocompatibility of gold make its nanostructures promising both as a contrast agent for in vivo optical imaging, and as a therapeutic agent for chemotherapeutic and/or photothermal treatment of cancer [14].
Despite a wide scope of possibilities offered by a plant-mediated synthesis, this mode of synthetic protocols is still in its infancy, when considered in-depth understanding of the actual course of the reduction, nucleation, and growth of nanoparticles. In most of the cases reported in the literature to date, there is a little attention paid to elucidation of the mechanistic pathway. Reduction of metal ions is mostly explained by a mixture of several different compounds. To the best of our knowledge, there are very few reports focused on precise explanation of synthetic route. For instance, Ahmad et al. suggested that free reactive hydrogen generated during the tautomeric transformation from the enol-form to the keto-form of flavonoids (i.e., luteolin and rosmarinic acids) is responsible for metal ions reduction [15]. In the case of flavonoids, other reduction scenario is also plausible – the internal mechanism of the conversion of ketones to carboxylic acids. The carbonyl groups or any π-electrons of flavonoids are able to chelate metal ions and then reduce them. This has been proven by Rajendiran et al. on the example of quercetin capable of reduction of Au3+ ions [16]. Furthermore, another mechanism can be connected with oxidation of hydroxyl groups of polyphenols to carbonyl groups or quinones, when metal ions are bioreduced [[17], [18], [19]]. Alternatively, in the case of terpenoids, the reducing potential is connected with the hydroxyl groups and their proton-releasing ability. This was proved by Srivastava et al. for eugenol with its sole hydroxyl group together with the inductive effect induced by the electron-withdrawing methoxy and allyl functional groups of the para and ortho position, respectively [20]. In general, hydroxyl and carboxyl groups of any natural macromolecules are suggested as the reactive sites allowing for the noncovalent interactions with metal ions and their efficient reduction [[21], [22], [23]]. Noteworthy, various functional groups of these compounds not only make them capable of triggering NPs formation but also strongly influence the physicochemical characteristics of the resulting NPs. Thus, plant extracts, containing both primary and secondary metabolites, can be considered as reducing, protecting (prevention of any further growth and particles aggregation during the initial stages of synthesis), and stabilizing agents (prevention of aggregation and agglomeration of the formed nanoparticles).
What is noteworthy, more attention has been currently devoted to the development of biocompatible and biodegradable functional assemblies emerging new directions for the further development of plant metabolites-based materials. These highly hybrid biomaterials can be promising vectors in the field of controlled-release biomedical applications, notably in cancer therapy [24,25]. In particular, biosynthesized Au NPs can become new-generation “magic bullets” against various types of tumors. Engineered multifunctionality on metal nanoparticles based on oxidative coupling assembly of plant metabolites assures selective activity against neoplasms over normal cells. Oxidative DNA damage preventive activity and antioxidant potential of plant extracts have been documented in-depth [26,27]. As well, anticancer activity for both various plant metabolites and Au NPs has been proved [[28], [29], [30]]. These findings offer enormous opportunities to design of novel hybrid or composite materials combining two active components. This, in turn allows discovery of unpredicted and unknown additive or synergistic biological effects.
Herein, we propose a development of energy-efficient, cost-effective and eco-friendly synthesis of Au NPs with application of the aqueous extract of Rosa damascena (Au@RD NPs). Deliberate use of Au NPs is aimed at their potential dual function as a carrier and a contributor to overall activity. Moreover, a final biomaterial, proposed for selective and effective fight against cancer and metastasis, is also composed of plant metabolites as active reagents, that modify surface of Au NPs. The morphology, size, crystal structure and composition of the resulting Au@RD NPs were precisely investigated by scanning and transmission electron microscopies (SEM, TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV–vis and FT-IR spectroscopies, particle size analysis, as well as zeta potential measurements. The emphasis was put on controlling the size of the gold NPs by varying the synthesis conditions and thereby modulating their physicochemical and biological properties. The cytotoxicity of Au@RD NPs was evaluated in vitro on selected normal cell line: peripheral blood lymphocytes (PBML) and two cancer cell lines: acute promyelocytic leukemia (HL60), human lung adenocarcinoma (A549) based on the assessment of cell viability via double-staining fluorescence assay. To gain more insight into the mode of action of Au@RD NPs the DNA damages in the treated cells were studied by the single-cell gel electrophoresis (comet assay). As well, activity of initiator caspases 3 and 7 was measured by a luminescent assay. The main purpose of biological research was to show selective cytotoxic action of Au@RD NPs towards cancer cells over normal cells in the studied experimental model in vitro.
Section snippets
Materials
Tetrachloroauric(III) acid (HAuCl4 × 3H2O) was used as a source of Au(III) ions required for the synthesis of Au NPs and was purchased from MERCK Co. The other chemicals: Folin−Ciocalteu reagent, gallic acid, quercetin (≥95%, HPLC grade), and quercetin-3-glucoside (≥90%, HPLC grade) were also purchased from MERCK Co. Before use, glass and all laboratory vessels were thoroughly washed in aqua regia and thoroughly dried. All reagents were of analytical grade and only double-distilled deionized
Controlled synthesis of Au@RD NPs using RD extract as a green multifunctional agent
The synthesis of Au@RD NPs was realized through a simple procedure based on reduction of tetrachloroauric(III) acid by the aqueous RD extract. The reduction of HAuCl4 in aqueous solution was carried out with a constant previously selected volume and concentration ratios of reactants (HAuCl4: RD; 1: 9 V: V) at different temperatures (22, 40, and 90 °C). The progress of Au@RD NPs formation was monitored by observation of surface plasmon resonance (SPR) band centered at around 520 nm,
Conclusions
A systematic and detailed study on synthesis of Au NPs using aqueous extract of RD flowers along with evaluation of their biological activity in vitro towards peripheral blood lymphocytes (PBML), acute promyelocytic leukemia (HL60), and human lung adenocarcinoma (A549) cell lines was presented. The progress of Au@RD NPs synthesis was monitored by UV − Vis, while powder XRD, XPS, SEM, and TEM techniques were applied for in-depth characterization of the resulting nanostructures. We showed that
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgment
This work was partially funded by the Scientific Fund of Andrzej Frycz Modrzewski Krakow University, Poland grant number 26/2018. The authors are very grateful to Małgorzata Kalemba-Drożdż from Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University for providing biological material (Rosa damascena) for research. The authors would also like to thank Paulina Musielak for her work on optimization of Au@RD NPs synthesis within realization of MSc thesis. Finally, the
References (57)
- et al.
Synthesis of metallic nanoparticles using plant extracts
Biotechnol. Adv.
(2013) - et al.
Nanoparticles with multiple properties for biomedical applications: a strategic guide
Nano Today
(2016) - et al.
Rapid synthesis of silver nanoparticles using dried medicinal plant of basil
Colloids Surf. B: Biointerfaces
(2010) - et al.
Green synthesis of silver and gold nanoparticles using Rosa damascena and its primary application in electrochemistry
Phys. E.
(2011) - et al.
Instant green synthesis of silver nanoparticles using Terminalia chebula fruit extract and evaluation of their catalytic activity on reduction of methylene blue
Process Biochem.
(2012) - et al.
Green synthesis of gold nanoparticles from leaf extract of Terminalia arjuna, for the enhanced mitotic cell division and pollen germination activity
Ind. Crop. Prod.
(2013) - et al.
Green synthesis and characterizations of silver and gold nanoparticles using leaf extract of Rosa rugosa
Colloids Surf. A Physicochem. Eng. Asp.
(2010) - et al.
Zeta-potential data reliability of gold nanoparticle biomolecular conjugates and its application in sensitive quantification of surface absorbed protein
Colloids Surf. B: Biointerfaces
(2016) - et al.
Biogenic synthesis of metallic nanoparticles by plant extracts
ACS Sustain. Chem. Eng.
(2013) - et al.
Bioinspired nanotheranostic agents: synthesis, surface functionalization, and antioxidant potential
ACS Biomater. Sci. Eng.
(2015)
Green chemistry for nanoparticle synthesis
Chem. Soc. Rev.
Embelin-mediated green synthesis of quasi-spherical and star-shaped Plasmonic nanostructures for antibacterial activity, photothermal therapy, and computed tomographic imaging
ACS Sustain. Chem. Eng.
Gold nanostructures: engineering their plasmonic properties for biomedical applications
Chem. Soc. Rev.
Aegle marmelos leaf extract and plant surfactants mediated green synthesis of Au and Ag nanoparticles by optimizing process parameters using Taguchi method
ACS Sustain. Chem. Eng.
Defining rules for the shape evolution of gold nanoparticles
J. Am. Chem. Soc.
Shape-controlled synthesis of metal nanocrystals: simple chemistry meets complex physics?
Angew. Chem. Int. Ed.
Mechanisms controlling crystal habits of gold and silver colloids
Adv. Funct. Mater.
Sustainable synthesis and improved colloidal stability of popcorn-shaped gold nanoparticles
ACS Sustain. Chem. Eng.
Stability and reactivity: positive and negative aspects for nanoparticle processing
Chem. Rev.
Exploiting intrinsic nanoparticle toxicity: the pros and cons of nanoparticle-induced autophagy in biomedical research
Chem. Rev.
Biological synthesis of silver and gold nanoparticles using apiin as reducing agent
Colloids Surf. B: Biointerfaces
Facile fabrication of branched gold nanoparticles by reductive hydroxyphenol derivatives
Langmuir
Biosynthesis of gold and silver nanoparticles by natural precursor clove and their functionalization with amine group
J. Nanopart. Res.
Natural Triterpenoid-tailored phosphate: in situ reduction of heavy metals spontaneously to generate electrochemical hybrid gels
ACS Appl. Mater. Interfaces
“Green” nanotechnologies: synthesis of metal nanoparticles using plants
Acta Nat.
Green and energy-efficient methods for the production of metallic nanoparticles
Beilstein J. Nanotechnol.
Modular assembly of biomaterials using polyphenols as building blocks
ACS Biomater. Sci. Eng.
Engineering multifunctional coatings on nanoparticles based on oxidative coupling assembly of polyphenols for stimuli-responsive drug delivery
J. Agric. Food Chem.
Cited by (24)
Lateral flow assay with green nanomaterials
2024, Comprehensive Analytical ChemistryGreen synthesis of gold nanoparticles using Andrographis paniculata leave extract for lead ion detection, degradation of dyes, and bioactivities
2023, Biochemical Engineering JournalPlant-mediated synthesis of nanoparticles and their applications: A review
2023, Materials Research BulletinRapid and facile synthesis of gold nanoparticles with two Mexican medicinal plants and a comparison with traditional chemical synthesis
2023, Materials Chemistry and PhysicsCitation Excerpt :Gold nanoparticles (AuNPs) are one of the most stable and used metallic nanoparticles; they usually have a size between 1 and 100 nm and exist in different morphologies, including nanospheres, nanorods, nanoshells, and nanocages [1].
Green synthesis and characterization parameters of gold nanoparticles
2023, Gold Nanoparticles for Drug DeliveryRecent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review
2022, Science of the Total EnvironmentCitation Excerpt :Although the bioreduction is an essential step in the biofabrication of plant-mediated nanoparticles, it still requires for more modifications. Indeed, phytochemicals are mainly responsible for capping and stabilizing nanoparticles (Kyzioł et al., 2021). Afreen et al. (2020) verified that flavonol glycosides, neoclerodane, diterpenoids, phytoecdysones, ergosterol, and iridoid glycosides present in the aqueous extract of A. bracteosa are such contributors to the prevention of clustering.