Stability Of Platinum Nanoparticles Research Articles

Optimizing Desmostachya bipinnata-derived platinum nanoparticles for enhanced antibacterial and biofilm reduction

This study presents the green synthesis and comprehensive characterization of platinum nanoparticles (PtNPs) using Desmostachya bipinnata (Db) extract, incorporated into two innovative mouthwash formulations (MW1 and MW2). UV–Vis spectroscopy confirmed the successful synthesis of PtNPs, with distinct absorption peaks between 250 and 600 nm. Fourier-transform infrared (FTIR) spectroscopy identified hydroxyl and carbonyl functional groups, critical for the bioreduction and stabilization of PtNPs. High-resolution transmission electron microscopy (HR-TEM) revealed uniformly dispersed, spherical nanoparticles with a size range of 10–20 nm, while dynamic light scattering (DLS) confirmed a hydrodynamic diameter of 10–30 nm and a low polydispersity index (PDI) of 0.238, indicating excellent stability. Both formulations exhibited robust antimicrobial, antibiofilm, and anti-plaque properties, with MW2 showing superior efficacy, particularly against Staphylococcus aureus and Escherichia coli, as well as a notable 70 % reduction in biofilm formation and a 60 % plaque reduction within 2 h of treatment. The study underscores the potential of Desmostachya bipinnata-derived PtNPs as a promising alternative to conventional mouthwash, offering enhanced antimicrobial efficacy, biofilm disruption, and plaque prevention, alongside excellent stability and biocompatibility for oral healthcare applications.

A physicochemical and spectroscopic characterization of novel erlotinib conjugates with platinum nanoparticles

Anticancer drug conjugates with metal nanoparticles are in the center of research interest due to the promising application potential in modern medicine. It was proved that plasmonic metal nanoparticles are not only drug carriers and amplifiers of biological effect but also sensors for tracking the fate of the drug in organisms and cells. The formation of drug conjugates with gold (AuNPs) and silver nanoparticles (AgNPs) are widely described in the literature whereas less attention was paid on the formation of anticancer drug conjugates with platinum nanoparticles (PtNPs). These studies were conducted to verify the main hypothesis that conjugates of erlotinib (ERL), belonging to drugs used in non-small cell lung cancer (NSCLCs) treatment, with PtNPs can be formed in electrostatically-driven self-organization process. PtNPs were prepared using a seed-mediated growth method. The micrographs obtained from transmission (TEM) and scanning (SEM) electron microscopy revealed that PtNPs exhibited quasi-spherical shape and an average size equal to 108 ± 11 nm. The stability of PtNPs under controlled pH and ionic strength was determined by dynamic (DLS) and electrophoretic (ELS) light scattering. The formation of ERL-PtNP conjugates was carried out under mild acidic conditions, at pH 4.9 and ionic strength 7 × 10−3 M. The spectroscopic analysis of formed conjugates was performed with the use of surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared adsorption spectroscopy (SEIRA). The spectroscopic investigation was carried out for positively charged conjugates. The performed SERS and SEIRA studies indicate that the prepared PtNPs provide effective surface enhancement in visible and infrared regions, respectively, ensuring the possibility to perform detailed characterization of the adsorption process on these metal nanostructures. The considered ERL indicates strong interaction with the PtNPs mainly through the quinazoline and the amino moieties. Also, the ethylene bridge takes part in the conjugates formation, while methoxy moiety and phenylacetylene ring remain at a certain distance from the metal surface. The comparison of obtained results with available literature data showed that the adsorption pattern of ERL strongly depends on the type of plasmonic nanoparticles because the phenylacetylene ring of ERL plays a crucial role in the formation of conjugates with AuNPs and AgNPs. Based on these findings, the chemical structure of ERL in the formed conjugates was proposed. It was concluded that the stable ERL-PtNP conjugates can exhibit comparable electrokinetic properties with ERL conjugates with AuNPs and AgNPs while the chemical structure of ERL layer on nanoparticle surface strongly depends on the plasmonic metal type.

Biofabricated platinum nanoparticles: therapeutic evaluation as a potential nanodrug against breast cancer cells and drug-resistant bacteria.

Use of plant extracts for the synthesis of various metal nanoparticles has gained much importance recently because it is a simple, less hazardous, conservative and cost-effective method. In this research work, platinum nanoparticles were synthesized by treating platinum ions with the leaf extract of Psidium guajava and their structural properties were studied using various characterization techniques. The formation of platinum nanoparticles was confirmed by the disappearance of the absorbance peak at 261 nm in UV-visible spectra. The results of gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR) analysis showed functional moieties responsible for bio-reduction of metal ions and stabilization of platinum nanoparticles. The use of dynamic light scattering (DLS) imaging techniques confirmed the formation of stable monodispersed platinum nanoparticles showing a zeta potential of −23.4 mV. The morphological examination using high resolution transmission electron microscopy (HR-TEM) and Scanning electron microscopy (SEM) confirmed the formation of spherical platinum nanoparticles with an average diameter of 113.2 nm. X-ray powder diffraction (XRD) techniques showed the crystalline nature of biosynthesized platinum nanoparticles with a face-centered cubic structure. The results of energy-dispersive X-ray spectroscopy (EDAX) showed 100% platinum content by weight confirming the purity of the sample. The cytotoxic effect of biosynthesized platinum nanoparticles assessed in a breast cancer (MCF-7) cell-line by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, revealed an IC50 of 167.2 μg ml−1. The results of a wound healing assay showed that treatment with platinum nanoparticles induced an anti-migratory effect on MCF-7 cells. In the cell cycle phase distribution, treatment with platinum nanoparticles inhibited cell proliferation as determined by flow cytometry with PI staining. Significant cell cycle arrest was detected at the G0/G1 phase with a notable decrease in the distribution of cells in the S and G2/M phases. The anti-bacterial activity of bio-synthesized platinum nanoparticles was evaluated against four pathogenic bacteria i.e. B. cereus (Gram positive), P. aeruginosa (Gram negative), K. pneumonia (Gram negative) and E. coli (Gram negative). The biosynthesized platinum nanoparticles were found to show dose-dependent inhibition against pathogenic bacteria with a significant effect on Gram-negative bacteria compared to Gram-positive bacteria. This synergistic blend of green and simplistic synthesis coupled with anti-proliferative and anti-bacterial properties makes these biogenic nanoparticles suitable in nanomedicine.

Tuning the Activity and Stability of Platinum Nanoparticles Toward the Catalysis of the Formic Acid Electrooxidation

Tuning the Activity and Stability of Platinum Nanoparticles Toward the Catalysis of the Formic Acid Electrooxidation

Bimodal Heterogeneous Functionality in Redox-Active Conjugated Microporous Polymer toward Electrocatalytic Oxygen Reduction and Photocatalytic Hydrogen Evolution.

The designing and development of heterogeneous catalysts for conversion of renewable energy to chemical energies by electrochemical as well as photochemical processes is at the forefront of energy research. In this work, two new donor-acceptor-based redox-active conjugated microporous polymers (CMPs) (TAPA-OPE-mix and TAPA-OPE-gly) are synthesized through Schiff base condensation reaction using a microwave synthesizer. Notably, the asymmetric and symmetric bola-amphiphilic nature of the OPE struts results in distinct nanostructuring and morphologies in the CMPs. Interestingly, both CMPs show impressive heterogeneous catalytic activity toward electrochemical O2 reduction and photocatalytic H2 evolution reactions, and therefore, act as bimodal electro- and photocatalytic porous organic materials. Furthermore, the redox-active property of the CMPs is exploited for in situ generation and stabilization of platinum nanoparticles (Pt), and these Pt@CMPs exhibit significantly enhanced photocatalytic activity.

Platinum nanocomposites and its applications: A review

Platinum is a transition metal that is very resistant to corrosion. It is used as catalyst for converting methyl alcohol to formaldehyde, as catalytic converter in cars, for hydrocracking of heavy oils, in Fuel Cell devices etc. Moreover, Platinum compounds are important ingredient for cancer chemotherapy drugs. The nano forms of Platinum due to its unique physico-chemical properties that are not found in its bulk counterpart, has been found to be of great importance in electronics, optoelectronics, enzyme immobilization etc. The stability of Platinum nanoparticles has supported its use for the development of efficient and durable proton exchange membrane Fuel Cells. The present review concentrates on the use of Platinum conjugated with various metal or compounds, to fabricate nanocomposites, to enhance the efficiency of Platinum nanoparticles. The recent advances in the synthesis methods of different Platinum-based nanocomposites and their applications in Fuel Cell, sensors, bioimaging, light emitting diode, dye sensitized solar cell, hydrogen generation and in biosystems has also been discussed.

Electrochemical reactivity and stability of platinum nanoparticles in imidazolium-based ionic liquids

The electrocatalytic activity of synthesized quasi-spherical Pt nanoparticles (NPs) has been studied, taking as a model the COads electrooxidation reaction in two imidazolium-based ionic liquids such as 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim+][NTf2 −] and 1-butyl-3-methylimidazolium tetrafluoroborate [C4mim+][BF4 −]. In particular, the effect of (i) water content, (ii) temperature, and (iii) nature of the room-temperature ionic liquid (RTIL) on the electrocatalytic behavior of these Pt NPs has been systematically evaluated. The obtained results show how important are those parameters, since the COads oxidation peak potential exhibits a great sensitivity depending on the water content, temperature, and nature of the RTIL used. Interestingly, the charge density associated with the COads electrooxidation peak strongly depends on the nature of the ionic liquid, which reflects the complexity of this electrocatalytic reaction in this media. Moreover, Pt NP electrocatalyst degradation in those RTILs, considered as a loss of electrochemically active area, has been evaluated and shows high stability despite the extreme potentials afforded in RTILs.

Synthesis and stabilization of Pt nanoparticles in core cross-linked micelles prepared from an amphiphilic diblock copolymer

In this study, an amphiphilic poly(ethylene glycol)methyl ether-block-poly(glycidyl methacrylate) diblock copolymer (MPEG-b-PGMA) was synthesized via atom transfer radical polymerization (ATRP), and its micellar solution was prepared in acetone/water mixture. Core cross-linked (CCL) micelles were synthesized by cross-linking the epoxy functional group of poly(glycidyl methacrylate) block with ethylenediamine. These CCL micelles were used in the synthesis and stabilization of platinum nanoparticles (PtNPs) in aqueous media. Transmission electron microscopy (TEM) images showed that well-dispersed PtNPs with a diameter of around 5 nm were formed within the MPEG-b-PGMA spherical CCL micelles having 22.0 ± 3.0 nm diameters. The mean TEM diameter of the PtNPs is of the order of several nanometers, which is consistent with the plasmon absorption peaks observed at around 205 and 261 nm. The catalytic activity of CCL micelle-PtNP dispersion was also investigated in the reduction of p-nitrophenol to p-aminophenol in the presence of NaBH4. The results showed that the PtNPs exhibit a good catalytic activity toward reduction of p-nitrophenol. CCL micelle-stabilized PtNP dispersions were stable for long periods of time without changing properties at room temperature. CCL micelles found to be good hostage or stabilizer for the NPs in aqueous media.

An efficient synthesis combining phosphorus dendrimers and 15-membered triolefinic azamacrocycles: towards the stabilization of platinum nanoparticles

The synthesis of a new series of phosphorus-containing dendrimers bearing as terminal groups triazatriolefinic macrocycles is reported, from generation 1 (6 macrocycles) to generation 4 (48 macrocycles). These macrocycles are linked to the dendrimers through diazaphospholane moieties (5-membered rings). The complexation ability of these dendrimers and of a compound possessing a single macrocycle was tested towards Pt2(dba)3. A discrete complex could be isolated only in the case of the model compound, whereas the dendrimers afford highly branched networks of Pt(0) nanoparticles interweaved with the dendrimers.

Stabilization of platinum nanoparticles on graphene by non-invasive functionalization

We have performed DFT–LDA calculations on the interaction of graphene with benzyl mercaptan, and on the role of the mercaptan in the adhesion of Pt nanoparticles. Our calculations indicate that Pt nanoparticles adhere more strongly to defect-free graphene than does benzyl mercaptan, which is essentially physisorbed. The role of the physisorbed mercaptan is to offer an abundance of –SH sites, to which the Pt bonding energy is greater than to graphene. This would lead to a higher deposition density of nanoparticles, which are decorated with chemisorbed mercaptan. The presence of benzyl mercaptan on the surfaces of Pt particles should also contribute to hindering the metallic phase coalescence.

Enantioselective catalytic hydrogenation of activated ketones using polymer-containing nanocomposites

In this paper formation and stabilization of platinum nanoparticles in the hypercrosslinked polystyrene matrix modified with (−)-cinchonidine and the use of this catalyst in the reaction of ethylpyruvate C O bond enantioselective hydrogenation are discussed. The series of the catalysts has been synthesized and the influence of the reducing agent nature and the modification method on catalytic properties of nanocomposites have been investigated. All the catalysts developed were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray fluorescent analysis, low temperature nitrogen adsorption, and CO adsorption followed by diffuse reflectance infrared Fourier transform spectroscopy.