Preparation Of Nanoparticles Research Articles

An on-demand source of nanoparticles for optomechanics

The generation of nanoparticles on demand, with good control over their size and shape, has been a challenge for nanotechnology and the rapidly growing field of levitated optomechanics. Here, we present the preparation, launch, and detection of single nanoparticles in both a buffer gas and in vacuum. A tightly focused ultrashort laser beam with low energy is used to melt, form, and release individual particles. Surface tension supports the creation of spherical particles from molten droplets whose radii can be controlled, here in the range r=80−200 nm, by varying the pulse energy. The particle source is compact and compatible with high vacuum. It can be applied equally to dielectrics and metals as demonstrated here for silicon and gold. The method is unique in its capability to generate pristine silicon spheres directly in vacuum, which would rapidly oxidize when formed in air. Silicon is of interest for levitated optomechanics, cavity cooling, and emerging quantum interference experiments because of its high infrared polarizability and its low work function. Combining the source with an infrared cavity, we characterize the launch velocity and transit dynamics for silicon and gold nanoparticles in a high-finesse cavity field.

Identification of true active sites in N-doped carbon-supported Fe2P nanoparticles toward oxygen reduction reaction

Transition metal-based nanoparticles (NPs) are emerging as potential alternatives to platinum for catalyzing the oxygen reduction reaction (ORR) in zinc-air batteries (ZAB). However, the simultaneous coexistence of single-atom moieties in the preparation of NPs is inevitable, and the structural complexity of catalysts poses a great challenge to identifying the true active site. Herein, by employing in situ and ex situ XAS analysis, we demonstrate the coexistence of single-atom moieties and iron phosphide NPs in the N, P co-doped porous carbon (in short, Fe-N4-Fe2P NPs/NPC), and identify that ORR predominantly proceeds via the atomic-dispersed Fe-N4 sites, while the presence of Fe2P NPs exerts an inhibitory effect by decreasing the site utilization and impeding mass transfer of reactants. The single-atom catalyst Fe-N4/NPC displays a half-wave potential of 0.873 V, surpassing both Fe-N4-Fe2P NPs/NPC (0.858 V) and commercial Pt/C (0.842 V) in alkaline condition. In addition, the ZAB based on Fe-N4/NPC achieves a peak power density of 140.3 mW cm−2, outperforming that of Pt/C-based ZAB (91.8 mW cm−2) and exhibits excellent long-term stability. This study provides insight into the identification of true active sites of supported ORR catalysts and offers an approach for developing highly efficient, nonprecious metal-based catalysts for high-energy–density metal-air batteries.

Controlled Spread of a Ag Layer from the Core to the Tip along the Branches of AuAg Nanostars for Improved SERS Detection of Okadaic Acid in Shellfish.

Plasmonic Au-Ag nanostars are excellent surface-enhanced Raman scattering (SERS) probes due to bimetallic coupling and the tip effect. However, the existing preparation methods of AuAg nanostars cannot achieve controlled growth of the Ag layer on the branches of nanostars and so cannot display their SERS to the maximum extent, thus limiting its sensitivity in biosensing. Herein, a novel strategy "PEI (polyethylenimine)-guided Ag deposition method" is proposed for synthesizing AuAg core-shell nanostars (AuAg@Ag NS) with a tunable distribution of the Ag layer from the core to the tip, which offers an avenue for investigating the correlation between SERS efficiency and the extent of spread of the Ag layer. It is found that AuAg@Ag NS with a Ag layer coated the whole branch has the strongest SERS performance because the coupling between the tips and Ag layer is maximized. Meanwhile, as a completely closed core-shell structure, AuAg@Ag NS can confine and anchor 4-ATP inside the Ag layer to avoid an unstable SERS signal. By connecting the aptamer, a reliable internal standard nanoprobe with a SERS enhancement factor (EF) up to 1.86 × 108 is prepared. Okada acid is detected through competitive adsorption of this SERS probes, and the detection limit is 36.6 pM. The results gain fundamental insights into tailoring the nanoparticle morphologies and preparation of internal standard nanoprobes and also provide a promising avenue for marine toxin detection in food safety.

Synthetic Protein Nanoparticles via Photoreactive Electrohydrodynamic Jetting.

Protein nanoparticles are an attractive class of materials for nanomedicine applications due to the intrinsic biocompatibility, biodegradability, and intrinsic functionality of their constituent proteins. Despite the clinical success of select protein nanoparticles, this class of nanocarriers remains understudied and underdeveloped compared to lipid and polymer nanoparticles due to challenges related to formulation optimization, large design space, and their structural complexity. In this work, a modular strategy for protein nanoparticle preparation based on the concept of photoreactive jetting is introduced. The process relies on continuous ultravioletirradiation during electrohydrodynamic (EHD) jetting of protein solutions that contain a homobifunctional photocrosslinker. Protein nanoparticles exhibit nanogel-like architectures comprised of proteins that are linked via synthetic moieties. Compared to conventional protein nanoparticles, this method reduces nanoparticle processing times to minutes, rather than hours to days. The inclusion of an emissive structural motif as the molecular scaffold of the photocrosslinker is used to study the supramolecular architecture of the stable nanoparticles via time-resolved fluorescence spectroscopy.

Preparation of Au Nanoparticle Loaded Biochar/Polydopamine Composites for Adsorption of MB and MG Dyes from Aqueous Solution

Preparation of Au Nanoparticle Loaded Biochar/Polydopamine Composites for Adsorption of MB and MG Dyes from Aqueous Solution

Preparation of gold nanoparticles by photolysis and radiolysis in alcohol solutions of functional hyperbranched polyorganosiloxane/H[AuCl4]: Effect of irradiation mode on nanoparticle size and formation mechanism

Ethanol solutions of functional hyperbranched polyorganosiloxanes (0.2 vol%) with a molar ratio of NH2(CH2)2NH-/H[AuCl4]x3H2O of 8/1 were used as precursors for nanocomposite preparation using UV photolysis and X-ray radiolysis. It was shown that various irradiation modes provide the synthesis of gold nanoparticles (AuNPs) with tunable sizes and narrow size distributions. It was established that size distributions of AuNPs depend on the excitation wavelength. AuNPs with an average size of 3.5 nm were obtained by the direct excitation of gold ions using UV light with λmax = 365 nm. Meanwhile, the action of a higher energy light (λ = 254 nm) on the metal polymer complexes resulted in formation of ultra-small nanoparticles with an average size of 1.5 nm, presumably due to the increased efficiency of their nucleation process. In the case of radiolysis with X-rays, reduction of Au3+ ions occurs due to reactions with radicals produced from ethanol and leads to the formation of AuNPs of 2–3 nm. Thus, the size distribution of the prepared AuNPs may be controlled by the irradiation mode, which critically affects nanomaterial properties. Additionally nanoparticles obtained by photochemical or radiation-chemical methods are free of chemical impurities, which is important for the development of functional materials.

Preparation and Characterization of Copper Nanoparticles Stabilized by Poly(vinyl alcohol) for Catalytic Oxidation of 1-Propanol

The aqueous solution of copper (II) complex of poly(vinyl alcohol) (PVA-Cu(II)) was characterized by conductimetric titration, UV-Vis spectroscopy and FTIR. The molar composition of the PVA-Cu(II) complex was determined to be equimolar. Subsequently, the PVA-Cu(II) complex was reduced by sodium borohydride to prepare copper nanoparticles (CuNPs) stabilized by PVA (PVA-CuNPs). According to DLS measurements in aqueous solution the average size of PVA-CuNPs was varied from 10 to 25 nm depending on the amount of sodium borohydride used for reduction. The optimal volume of sodium borohydride to obtain 96 % PVA-CuNPs with 10 nm size was found to be 3 mL of NaBH4 (0.5 mol×L–1). The PVA-CuNPs were then deposited onto SiO2 support to obtain SiO2/PVA-CuNPs nanocatalyst for the oxidation of 1-propanol. The SEM image and XRD spectrum of SiO2/PVA-CuNPs nanocatalyst showed the deposition of PVA-CuNPs on the surface of SiO2. The resulting SiO2/PVA-CuNPs nanocatalyst was used for the oxidation of 1-propanol to propionaldehyde by molecular oxygen in a batch-type catalytic reactor at 20oС and atmospheric pressure. The optimum catalyst mass and reaction time were found for the conversion of 1-propanol to propionaldehyde with yields ranging from 61.4 % to 87.8 %. Criteria of hydrodynamic similarity (Re, Pr’, Sh), overall volumetric mass transfer coefficient (), and economic metric (STY) were evaluated. 1-Propanol reacted with the decomposed atomically adsorbed oxygen atoms on the Cu(111), (220) surfaces to form propionaldehyde and water.

Green preparation of nanoparticles with potential as nanocarriers for bioactive compounds using the valorisable biopolymers hyaluronic acid and hemoglobin

Proteins and polysaccharides are biopolymers that can be obtained from sustainable resources and can add value to biomaterials for medical and food science applications. Nanoparticles (NPs) of hemoglobin (Hb) and hyaluronic acid (HA) are prepared by electrostatic complexation of HA and Hb and thermal treatment at mild temperature under a totally biocompatible methodology. The electrostatic interaction between the anionic polysaccharide HA and Hb at conditions (pH 4) where the protein is strongly positively charged (net charge +54) is used to form protein/polysaccharide complexes of well-defined size distribution (100–200 nm). The complexes are stabilized against disintegration at pH 7 by thermal treatment at 60 °C for 2 h. The content of Hb in α-helices (∼47%) and β-sheets (∼19%) does not change upon thermal treatment. The NPs have pH-responsive surface charge and ability to bind hydrophobic compounds however the surface activity of the protein is not present in the NPs. This work motivates the use of renewable biomacromolecules from sustainable resources for nanocarrier applications.

The Preparation of Tetraarylethylene-Based Porous Polymer Nanoparticles for the Sensitive Detection of Picric Acid in Aqueous Media

The Preparation of Tetraarylethylene-Based Porous Polymer Nanoparticles for the Sensitive Detection of Picric Acid in Aqueous Media

Eco-Friendly One-Pot Synthesis of Tetrahydrobenzo[b]Pyran and Dihydropyrano[3,2-c]Chromene Derivatives Using Functionalized Fe3O4@SiO2@SO3H Under MWI

The present work describes a greener method of preparation of Fe3O4 nanoparticles, which are then functionalized to Fe3O4@SiO2@SO3H, and employed in the one-pot three-component synthesis of tetrahydrobenzo[b]pyran and dihydropyrano[3,2-c]chromene derivatives. These synthesized derivatives are an important class of heterocyclic scaffolds and exhibit significant potential as anti-coagulant, diuretic, spasmolytic, anticancer, and anti-anaphylactic agents. The prepared MNP-based catalysts were characterized using XRD, FE-SEM, VSM, TG-DTA, and Raman spectroscopy. The synthesis of derivatives involved the condensation reaction of enolizable compounds with aldehyde, dimedone, and ethyl cyanoacetate for tetrahydrobenzo[b]pyran, and the reaction of aromatic aldehyde, 4-hydroxycoumarin, and malononitrile for dihydropyrano[3,2-c]chromene synthesis. The reaction was optimized using different techniques such as stirring, ultrasonication, and microwave irradiation, with microwave irradiation method demonstrating faster product separation and high yield. The homogeneity of the isolated product was analyzed by FT-IR,1H-13C-NMR, and mass spectrometry. The advantages of this method include its simplicity, eco-friendliness, cost-effectiveness, and it also evades the use of toxic metals and solvents. The product is easily isolated through a simple workup process and recrystallization using ethanol yields pure product isolation.

Preparation and antibacterial ability of photodynamic antibacterial nanoparticles with ammonium cationic groups

With the increasing infection of drug-resistant bacteria, it has become a great challenge for researchers to find new approaches to eradicate drug-resistant bacteria and their biofilms. Photodynamic antimicrobial chemotherapy (PACT) is an indispensable part of the new anti-bacterial strategy because of its unique anti-bacterial mechanism, which can effectively inactivate drug-resistant bacteria without inducing further drug resistance. In this work, nanoparticles with N-isopropylacrylamide and methacryloxyethyltrimethyl ammonium chloride as monomers, and loaded with a fluorescent conjugated polymer were successfully prepared by microemulsion polymerization. The average particle size ranged from 100 to 200 nm. The nanoparticles could disperse in water steadily according to their zeta potential analysis. The nanoparticles generated singlet oxygen upon exposing to light with wavelength of 500–700 nm. Their PACT efficiency was investigated against Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus respectively. The results indicated that the antibacterial ability of nanparticles were excellent as the concentration was more than 0.01 mg/mL and the illumination time was 30 min. When the mass concentration of the nanoparticles was equal to or more than 0.05 mg/mL, the antibacterial mechanism was dominated by cation action, and when the concentration was equal or lower than 0.01 mg/mL, the antibacterial ability of the nanoparticles was improved effectively by photodynamic action. The antibacterial rate of the nanoparticle solutions against the bacteria in the biofilm was quantitatively studied, and it was proved that the nanoparticles eliminated bacteria in the biofilm effectively with a nanoparticle concentration of 0.2 mg/mL or more. The results indicated that the nanoparticles could effectively penetrate the biofilm to kill bacteria inside the biofilm by light illumination.

(Invited) Plasmonic Nanofabrication of Chiral Nanodisk Ensembles

Chiral plasmonic nanostructures attract attention because those could be applied to enantioselective chemical sensors, optical isolators, light sources for circularly polarized light (CPL), metasurfaces, and metamaterials. In many cases, chiral plasmonic nanostructures are fabricated by a top-down method such as electron beam lithography (EBL). Since EBL is time-consuming and expensive, we have developed photoelectrochemical methods in which a site-selective reaction is driven by optical near field generated around anisotropic metal nanoparticles under right- or left-CPL. As anisotropic metal precursors for preparation of chiral nanoparticles, we have used gold or silver nanocuboids, nanorods, nanocubes, and triangular or hexagonal nanoplates so far.1-5 In the present work we demonstrate that laterally isotopic, circular nanodisks can also be used as precursors for the preparation of chiral nanostructures.We prepared ensembles of circular gold nanodisks on a glass plate by a nanosphere lithography method. A glass plate was coated with a gold thin film, and an array of polystyrene spheres (500 nm diameter) was prepared on the gold film. The polystyrene spheres were etched by oxygen plasma, and the exposed gold film was etched by argon ion milling. As a result, an ensemble of gold nanodisks (~200 nm diameter) was obtained. Each nanodisk was capped with a polystyrene cone, and the cap was removed by sonication in toluene if necessary. We used both capped and uncapped nanodisk ensembles. The ensemble was irradiated with visible right- or left-CPL in the presence of silver ions and sodium citrate. The obtained Au-Ag nanostructures exhibited circular dichroism (CPL), indicating that the nanostructures have chirality. Initial deposition at arbitrary site may break the geometric symmetry, resulting in the growth into chiral structures. Saito, K.; Tatsuma, T. Nano Lett. 2018, 18, 3209–3212.Morisawa, K.; Ishida, T.; Tatsuma, T. ACS Nano 2020, 14, 3603–3609.Shimomura, K.; Nakane, Y.; Ishida, T.; Tatsuma, T. Appl. Phys. Lett. 2023, 122, 151109.Homma, T.; Sawada, N.; Ishida, T.; Tatsuma, T. ChemNanoMat 2023, 9, e202300096.Ishida, T.; Isawa, A.; Kuroki, S.; Kameoka, Y.; Tatsuma, T. Appl. Phys. Lett. 2023, 123, 061111.

Design and optimization of acetazolamide nanoparticle-laden contact lens using statistical experimental design for controlled ocular drug delivery

This study aims to formulate and evaluate Eudragit nanoparticles-laden hydrogel contact lenses for controlled delivery of acetazolamide (ACZ) using experimental design. Eudragit S-100 was selected for the preparation of nanoparticles. The optimization of Eudragit S100 concentration (X1), polyvinyl alcohol concentration (X2), and the sonication time (X3) was attempted by applying a central composite experimental design. Mean size of nanoparticles (nm), percent in vitro drug release and drug leaching from the ACZ-ENs laden contact lens were considered as dependent variables. Nanoparticles-laden contact lens was prepared through the direct loading method and characterized. Optimum check-point formulation was selected based on validated quadratic polynomial equations developed using response surface methodology. The optimized formulation of ACZ-ENs exhibited spherical shape with a size of 244.3 nm and a zeta potential of −13.2 mV. The entrapment efficiency of nanoparticles was found to be 82.7 ± 1.21%. Transparent contact lenses loaded ACZ-ENs were successfully prepared using the free radical polymerization technique. ACZ-ENs incorporated in contact lens exhibited a swelling of 83.4 ± 0.82% and transmittance of 80.1 ± 1.23%. ACZ-ENs showed a significantly lower burst release of the drug when incorporated in the contact lens and release was sustained over a period of 24 h. The sterilized formulation of ACZ-ENs laden contact lens did not show any sign of toxicity in rabbit eyes. ACZ-ENs incorporated in contact lens could be considered as a potential alternative in glaucoma patients due to their ability to provide sustained drug release and thus enhance patient compliance.

Condensed tannins from Pinus radiata bark: Extraction and their nanoparticles preparation in water by green method

This work reports for the first time the production of condensed tannin nanoparticles stable in water via modification with glycine betaine. Pine bark, as a byproduct from the paper industry, was used as a source of condensed tannins of high molecular weight. Different glycine betaine concentrations were tested to produce condensed tannin nanoparticles, and the obtained nanoparticles were subjected to several characterization techniques (Dynamic Light Scattering, Field emission scanning electron microscopy, Zeta potential, Fourier transform infrared spectroscopy-Attenuated total reflectance, thermogravimetric analysis). The results showed that the highest stability possessed nanoparticles with 40 wt% glycine betaine. The average particle size distribution evaluated by scanning microscopy was 124 nm. Besides, the glycine betaine-modified condensed tannin nanoparticles demonstrated higher thermal stability with the starting degradation temperature at 238 °C. Finally, obtained nanoparticles showed an antioxidant capacity of 34,209 ± 2194 μmol ET/100 g and low cytotoxicity towards healthy human cells, representing the high potential to be used as a carrier of active compounds in agriculture, food, drug and medical sector.

Biomass extract-mediated preparation of magnesium-doped nickel oxide nanoparticles and their in vitro bioactivities assessment

Biomass extract-mediated fabrication of metal oxide nanoparticles received significant attention in material research because it is eco-friendly, cost-effective, and easy to scalability. Here, the fabrication of Boerhavia diffusa leaf extract (BDE)-mediated magnesium-doped nickel oxide nanoparticles (Mg-doped-NiO-BDE) and their in vitro bioactivities are reported. Several characterization procedures are used to characterize the prepared NiO nanoparticles. Field emission scanning electron microscopy and transmission electron microscopy images exhibit that the Mg-doped-NiO-BDE are distorted spherical. The X-ray diffraction showed that the average crystallite sizes of the nanoparticles are around 51–55 nm. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy analysis results confirm that the NiO is produced, and Mg-doping has occurred in the adopted reaction condition. The doped NiO NPs exhibit broad-spectrum antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as well as antifungal action against Aspergillus niger (A. nigar). The antioxidant, anti-inflammatory, and anti-diabetic efficiencies of doped-NiO NPs (concentration = 400 μg/mL) are around 65 %, 89 %, and 87 %, respectively. The Mg-doped-NiO-BDE nanoparticles show around 75 % viability against the human lung cancer cell line (A459) with a concentration of up to 100 μg/mL, while the IC50 value is 185.6 μg/mL. The scratch test is executed with the mouse fibroblast cells (L929) in which doped-NiO NPs exhibit around 36 % wound-closing ability. The above results signify that the fabricated Mg-doped-NiO-BDE is a potent bioactive material that could be used for biomedical applications.

Phytochemical preparation of Zinc Stannate nanoparticles by using lemon and grapefruit peels for removal of cadmium ions

The synthesis of Zinc Stannate (Zn2SnO4) nanoparticles may be achieved by utilizing lemon and grapefruit peels, as indicated by the results of this study. This analysis outlines a sustainable, cost-effective, and readily available approach. The Zn2SnO4 nanoparticles were generated biologically and were discovered to have a cubic crystalline structure, as established by structural analysis using Rietveld refinement. TEM microstructural examinations revealed that Zn2SnO4 nanoparticles exhibit a homogeneous distribution and possess an average diameter of around 21 nm. The Zn2SnO4 nanoparticles have an optical energy band gap of 3.05 eV and demonstrate a UV region peak, which showed that Zn2SnO4 nanoparticles were being formed. More precisely, the pH of the solution greatly affects the absorption of Cd2+ ions. Kinetic analysis involves the use of two types of models: pseudo-first-order and pseudo-second-order. The previous model yields an R2 value of 0.9031 and a rate constant (k1) of 0.41 × 10−2 min−1. However, the pseudo-second-order model provides a better match, as seen by its very high R2 value of 0.9932 and rate constant (k2) value of 4.4 × 10−3 g.(mg.min)−1. In addition, isotherm modeling shows that the experimental data closely match the Freundlich isotherm model.

Preparation of Biomimetic Selenium-Baicalein Nanoparticles and Their Targeted Therapeutic Application in Nonsmall Cell Lung Cancer.

In this study, we prepared bionic selenium-baicalein nanoparticles (ACM-SSe-BE) for the targeted treatment of nonsmall cell lung cancer. Due to the coating of the A549 membrane, the system has homologous targeting capabilities, allowing for the preparation of target tumor cells. The borate ester bond between selenium nanoparticles (SSe) and baicalein (BE) is pH-sensitive and can break under acidic conditions in the tumor microenvironment to achieve the targeted release of BE at the tumor site. Moreover, SSe further enhances the antitumor effect of BE by increasing the production of ROS in tumor cells. Transmission electron microscopy (TEM) images and dynamic light scattering (DLS) showed that the ACM-SSe-BE had a particle size of approximately 155 ± 2 nm. FTIR verified the successful coupling of SSe and BE. In vitro release experiments indicated that the cumulative release of ACM-SSe-BE at pH 5.5 after 24 h was 69.39 ± 1.07%, which was less than the 20% release at pH 7.4, confirming the pH-sensitive release of BE in ACM-SSe-BE. Cell uptake experiments and in vivo imaging showed that ACM-SSe-BE had good targeting ability. The results of MTT, flow cytometry, Western blot, and cell immunofluorescence staining demonstrated that ACM-SSe-BE promoted A549 cell apoptosis and inhibited cell proliferation. The in vivo antitumor results were consistent with those of the cell experiments. These results clearly suggested that ACM-SSe-BE will be a promising bionic nanosystem for the treatment of nonsmall cell lung cancer.

One pot green process for facile fractionation of sorghum biomass to lignin, cellulose and hemicellulose nanoparticles using deep eutectic solvent

Complete valorization of lignocellulosic biomass is crucial for bio-based biorefineries to fulfil the circular bioeconomy concept. However, the existence of lignin carbohydrate complexes (LCC) in biomass hinders the simultaneous fractionation of biomass components, such as lignin, hemicellulose and cellulose, for subsequent biorefining processes. This study explores for the first time a novel approach tailored for the deconstruction of sorghum biomass components through efficient breakdown of LCC. Selective targeting of the major LCC linkages binding xylan and lignin was performed using an ultrasound-assisted deep eutectic solvent under mild treatment conditions. This process yielded a maximum cellulose content of 98.3 %, hemicellulose content of 95.2 %, and lignin content of 94.6 %, with the highest purities of 99.43 %, 96.71 %, and 98.12 %, respectively. FTIR, 2D-HSQC NMR and XRD analyses confirmed that most of the structural properties of lignin, hemicellulose, cellulose are retained. The lignocellulosic components were successfully valorised to cellulose, hemicellulose, and lignin nanoparticles with mean sizes of 64.5 ± 6 nm, 72.8 ± 4 nm and 57.2 ± 8 nm respectively, with good thermal stability. The proposed green process enables the complete utilization of agro-residue feedstock for the preparation of biomass-derived nanoparticles, thereby accelerating the economic and industrial prospects of bio-based biorefineries.

Design and decoration of copper nanoparticles into lignosulfonate-starch bionanocomposite: Characterization and evaluation of its therapeutic properties on burn wound

In this report, eco-friendly synthesis for the production of copper nanoparticles by employing the sodium lignosulfonate (NaLS) mixed starch composite (NaLS-Starch/Cu NPs). NaLS-Starch mixed hydrogel has notable reducing and stabilizing potential for preparation of Cu nanoparticles. Characterization of NaLS-Starch/Cu NPs bionanocomposite was subjected to analysis of spectroscopic and microscopic techniques, including FE-SEM, TEM, EDS-elemental mapping, particle size distribution, XRD and ICP. TEM images displayed the spherical structured NaLS-Starch/Cu NPs, averaging 5–10 nm size. NaLS-Starch/Cu NPs were applied to cure the induced burn wounds in 60 Wistar rats. A group was considered as control group. The animals were treated with basal, tetracycline 3 % and NaLS-Starch/Cu NPs 3 % for 30 days and the treatment efficacy was determined according to the burn wound area reduction and molecular and histological characteristics. Taken together, these results support therapeutic use of NaLS-Starch/Cu NPs as potent ointment that may be proposed for burn wound healing. NaLS-Starch/Cu NPs ointment increased the levels of platelet-derived growth factors (PDGF) and fibroblast growth factor (bFGF). The mean wound surface, in all groups treated by NaLS-Starch/Cu NPs was larger than control group.

Antibacterial Nanoplatelets via Crystallization-Driven Self-Assembly of Poly(l-lactide)-Based Block Copolymers.

Membrane-active antimicrobial materials are promising substances to fight antimicrobial resistance. Herein, crystallization-driven self-assembly (CDSA) is employed for the preparation of nanoparticles with different morphologies, and their bioactivity is explored. Block copolymers (BCPs) featuring a crystallizable and antimicrobial block were synthesized using a combination of ring-opening and photoiniferter RAFT polymerizations. Subsequently formed nanostructures formed by CDSA could not be deprotected without degradation of the structures. CDSA of deprotected BCPs yielded 2D diamond-shaped nanoplatelets in MeOH, while spherical nanostructures were observed for assembly in water. Platelets exhibited improved antibacterial capabilities against two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) compared to their spherical counterparts. The absence of hemolytic activity leads to the excellent selectivity of platelets. A mechanism based on membrane permeabilization was confirmed via dye-leakage assays. This study emphasized the impact of the shape of nanostructures on their interaction with bacterial cells and how a controlled assembly can improve bioactivity.