Synergistic ROS Generation via Core-Shell Nanostructures with Increased Lattice Microstrain Combined with Single-Atom Catalysis for Enhanced Tumor Suppression.

This study emphasizes the innovative application of FePt and Cu core-shell nanostructures with increased lattice microstrain, coupled with Au single-atom catalysis, in significantly enhancing •OH generation for catalytic tumor therapy. The combination of core-shell with increased lattice microstrain and single-atom structures introduces an unexpected boost in hydroxyl radical (•OH) production, representing a pivotal advancement in strategies for enhancing reactive oxygen species. The creation of a core-shell structure, FePt@Cu, showcases a synergistic effect in •OH generation that surpasses the combined effects of FePt and Cu individually. Incorporating atomic Au with FePt@Cu/Au further enhances •OH production. Both FePt@Cu and FePt@Cu/Au structures boost the O2 → H2O2 → •OH reaction pathway and catalyze Fenton-like reactions. This enhancement is underpinned by DFT theoretical calculations revealing a reduced O2 adsorption energy and energy barrier, facilitated by lattice mismatch and the unique catalytic activity of single-atom Au. Notably, the FePt@Cu/Au structure demonstrates remarkable efficacy in tumor suppression and exhibits biodegradable properties, allowing for rapid excretion from the body. This dual attribute underscores its potential as a highly effective and safe cancer therapeutic agent.

Detection of Femtomolar Amyloid-ß Peptides for Early-Stage Identification of Alzheimer's Amyloid-ß Aggregation with Functionalized Gold Nanoparticles.

Progressive amyloid-ß (Aß) fibrillar aggregates have long been considered as the pathogenesis of Alzheimer's disease (AD). Biocompatible and stable cysteine-Aß peptide-conjugated gold nanoparticles (Cys-Aß@AuNP) are demonstrated as suitable materials for detecting subfemtomolar Aß peptides in human plasma. Incubation with Aß peptides causes the Cys-Aß@AuNP to aggregate and changes its absorption spectra. The spectral change is especially apparent and noticeable when detecting subfemtomolar Aß peptides, and the aggregates contain only two or three AuNPs. Cys-Aß@AuNP can also be used to identify early-stage Aß oligomerization, which is not possible using the conventional method, in which the fluorescence of thioflavin-T is measured. The ability to detect Aß oligomerization can facilitate therapeutics for AD. In addition, the binding of Aß peptides by Cys-Aß@AuNP in combination with centrifugation redirects the conventional Aß aggregation pathway and can effectively inhibit the formation of toxic Aß oligomers or fibrils. Therefore, the proposed Cys-Aß@AuNP can also be used to develop effective therapeutic agents to inhibit Aß aggregation. The results obtained in this study are expected to open revolutionary ways to both detect and inhibit Aß aggregation at an early stage.

Simulation and Verification of the Direct Current Electric Field on Fabricating High Porosity f-MWCNTs Thin Films by Electrophoretic Deposition Technique.

Electrophoretic deposition (EPD) is the potential process in high porosity thin films' fabrication or complex surface coating for perovskite photovoltaics. Here, the electrostatic simulation is introduced to optimize the EPD cell design for the cathodic EPD process based on functionalized multiwalled carbon nanotubes (f-MWCNTs). The similarity between the thin film structure and the electric field simulation is evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) results. The thin-film surface at the edge has a higher roughness (Ra) compared to the center position (16.48 > 10.26 nm). The f-MWCNTs at the edge position tend to be twisted and bent due to the torque of the electric field. The Raman results show that f-MWCNTs with low defect density are more easily to be positively charged and deposited on the ITO surface. The distribution of oxygen and aluminum atoms in the thin film reveals that the aluminum atoms tend to have adsorption/electrostatic attraction to the interlayer defect positions of f-MWCNTs without individually depositing onto the cathode. Finally, this study can reduce the cost and time for the scale-up process by optimizing the input parameters for the complete cathodic electrophoretic deposition process through electric field inspection.

Fabrication of Glutaraldehyde Vapor Treated PVA/SA/GO/ZnO Electrospun Nanofibers with High Liquid Absorbability for Antimicrobial of Staphylococcus aureus.

In this study, we aim to develop organic-inorganic hybrid nanofibers containing high moisture retention and good mechanical performance as an antimicrobial dressing platform. The main theme of this work focuses on several technical tasks including (a) the electrospinning process (ESP) to produce organic polyvinyl alcohol/sodium alginate (PVA/SA) nanofibers with an excellent diameter uniformity and fibrous orientation, (b) the fabrication of inorganic nanoparticles (NPs) as graphene oxide (GO) and ZnO NPs to be added to PVA/SA nanofibers for enhancement of the mechanical properties and an antibacterial function to Staphylococcus aureus (S. aureus), and then (c) the crosslinking process for PVA/SA/GO/ZnO hybrid nanofibers in glutaraldehyde (GA) vapor atmosphere to improve the hydrophilicity and moisture absorption of specimens. Our results clearly indicate that the uniformity nanofiber with 7 wt% PVA and 2 wt% SA condition demonstrates 199 ± 22 nm in diameter using an electrospinning precursor solution of 355 cP in viscosity by the ESP process. Moreover, the mechanical strength of nanofibers was enhanced by 17% after the handling of a 0.5 wt% GO nanoparticles addition. Significantly, the morphology and size of ZnO NPs can be affected by NaOH concentration, where 1 M NaOH was used in the synthesis of 23 nm ZnO NPs corresponding to effective inhibition of S. aureus strains. The PVA/SA/GO/ZnO mixture successfully performed an antibacterial ability with an 8 mm inhibition zone in S. aureus strains. Furthermore, the GA vapor as a crosslinking agent acting on PVA/SA/GO/ZnO nanofiber provided both swelling behavior and structural stability performance. The swelling ratio increased up to 1.406%, and the mechanical strength was 1.87 MPa after 48 h of GA vapor treatment. Finally, we successfully synthesized the hybrid nanofibers of GA-treated PVA/SA/GO/ZnO accompanied with high moisturizing, biocompatibility, and great mechanical properties, which will be a novel multi-functional candidate for wound dressing composites for patients receiving surgical operations and first aid treatments.

Atomically dispersed golds on degradable zero-valent copper nanocubes augment oxygen driven Fenton-like reaction for effective orthotopic tumor therapy.

Herein, we employ a galvanic replacement approach to create atomically dispersed Au on degradable zero-valent Cu nanocubes for tumor treatments on female mice. Controlling the addition of precursor HAuCl4 allows for the fabrication of different atomic ratios of AuxCuy. X-ray absorption near edge spectra indicates that Au and Cu are the predominant oxidation states of zero valence. This suggests that the charges of Au and Cu remain unchanged after galvanic replacement. Specifically, Au0.02Cu0.98 composition reveals the enhanced •OH generation following O2 → H2O2 → •OH. The degradable Au0.02Cu0.98 released Cu+ and Cu2+ resulting in oxygen reduction and Fenton-like reactions. Simulation studies indicate that Au single atoms boot zero-valent copper to reveal the catalytic capability of Au0.02Cu0.98 for O2 → H2O2 → •OH as well. Instead of using endogenous H2O2, H2O2 can be sourced from the O2 in the air through the use of nanocubes. Notably, the Au0.02Cu0.98 structure is degradable and renal-clearable.

Localized Surface Plasmon Resonance-Based Colorimetric Assay Featuring Thiol-Capped Au Nanoparticles Combined with a Mobile Application for On-Site Parathion Organophosphate Pesticide Detection.

In this study, we employed a dual strategy for parathion organophosphate pesticide (parathion) detection; first, we used a localized surface plasmon resonance (LSPR)-based colorimetric sensor featuring thiol-capped Au NPs, namely cysteine (Cys)@Au NPs, 11-mercaptoundecanoic acid (11-MUA)@Au NPs, and glutathione (GSH)@Au NPs, via acetylcholinesterase (ACHE) and acetylthiocholine (ATCH) enzyme-mediated hydrolysis reactions; second, we developed a color analysis toxicity-sensing app (Toxin APP). Positively charged thiocholine (TCH) molecules, which were continuously generated via hydrolysis, subsequently conjugated with thiol-capped Au NPs, causing Au NP aggregation through electrostatic attractions. The degree of aggregation of the thiol-capped Au NPs was influenced by parathion concentrations in the range 0 to 108 ppt, because parathion acted as an ACHE inhibitor by controlling the amount of TCH generated. Based on the values of LSPR absorbance ratio, the limits of detection (LODs) of three types thiol-capped Au NPs were determined to be 100 ppt using ultraviolet-visible spectroscopy measurements. However, the aggregation efficiency of GSH@Au NPs was lower than that of the others regarding gradual changes in their color and LSPR absorbance band. Furthermore, we designed Toxin APP for color analysis which consists of three modules: processing, database collection, and communication. Toxin APP could on-site and precisely detect the color changes of GSH@Au NPs at parathion concentrations in the ranges of 100 ppt to 1, 10, and 100 ppm and could distinguish between OP and non-OP pesticides (e.g., fipronil) in tap water samples with high sensitivity and selectivity. Moreover, the concentration of residual parathion in real samples (tomato and strawberry) was quantified based on the color changes of GSH@Au NPs detected using Toxin APP. Therefore, the combination of an LSPR-based colorimetric assay and Toxin APP can be a reliable method for the facile and rapid detection of parathion in food and water samples.

Plasmonic Gold Nanomaterials as Photoacoustic Signal Resonant Enhancers for Cysteine Detection.

The development of photoacoustic systems is important for the real-time detection of cysteine (Cys), a biothiol in biological systems that serves as a significant biomarker for human health. Advanced photoacoustic (PA) signals with colloidal plasmonic Au nanomaterials rely on the efficient conversion of light to energy waves under moderately pulsed laser irradiation. In this study, we synthesized Cys-capped Au nanorods (Au@Cys NRs) and Cys-capped Au nanoparticles (Au@Cys NPs) through a conjugate of three Cys concentrations (10, 100, and 1000 µM). These plasmonic Au nanomaterials can be used as a PA resonance reagent due to their maximum localized surface plasmon resonance (LSPR) absorption bands at 650 nm and 520 nm in Au NRs and Au NPs, respectively. Subsequently, the PA signals were noticeably increased proportionally to the concentrations in the Au@Cys NRs and Au@Cys NPs under 658 nm and 520 nm laser irradiation, respectively, according to our portable photoacoustic system. Furthermore, PA signal amplitudes in Cys detection are boosted by ~233.01% with Au@Cys NRs and ~102.84% with Au@Cys NPs enhancement, compared to free Cys, according to ultrasound transducers at frequencies of 3 MHz.

1550 nm excitation-responsive upconversion nanoparticles to establish dual-photodynamic therapy against pancreatic tumors.

The second near-infrared biological window b (NIR-IIb, 1500-1700 nm) is recently considered as the promising region for deeper tissue penetration. Herein, a nanocarrier for 1550 nm light-responsive dual-photodynamic therapy (PDT) is developed to efficiently boost singlet oxygen (1O2) generation. The dual-photosensitizers (PSs), rose bengal (RB) and chlorin e6 (Ce6), are carried by the silica-coated core-shell LiYbF4:Er@LiGdF4 upconversion nanoparticles (UCNPs), forming UCNP/RB,Ce6. Following 1550 nm laser irradiation, the upconversion emission of UCNP/RB,Ce6 in both green (∼550 nm) and red (∼670 nm) colors is fully utilized to activate RB and Ce6, respectively. The simultaneous triggering of dual-PS generates an abundant amount of 1O2 resulting in boosted PDT efficacy. This dual-PDT nanocarrier presents an enhanced anticancer effect under single dose treatment in comparison with the single-PS ones from in vitro and in vivo treatments. The marriage between the boosted dual-PDT and 1550 nm light excitation is anticipated to provide a new avenue for non-invasive therapy.

An Advanced Hand-Held Microfiber-Based Sensor for Ultrasensitive Lead Ion Detection.

This study demonstrated a l-glutathione-modified nonadiabatic microfiber sensor to detect a trace level of heavy metal ions in aqueous solution. The sensor showed an exclusively selective response to Pb2+ among other metal ions and a measured detection limit of 5 µg/L, lower than the maximum allowable limit of Pb2+ in drinking water by the World Health Organization. Moreover, a novel compact all-fiber-based interrogation scheme was proposed to promote the development of a portable hand-held system for on-site measurement. The presented scheme does not require costly and bulky laboratory equipment but operates based on the reflected optical power of two fiber Bragg gratings (FBG), measured using photodetectors independently.

Large-Scale Nanofabrication of Designed Nanostructures Using Angled Nanospherical-Lens Lithography for Surface Enhanced Infrared Absorption Spectroscopy.

Nanophotonics has been a focused research discipline for the past decade and has resulted in many novel concepts that promise to change human life. However, the actual penetration of this research into real products is severely limited mostly due to the slow development of economic nanofabrication. In this study, we have demonstrated a versatile and low-cost nanofabrication method referred to as "angled nanospherical-lens lithography (A-NLL)", which is able to produce large-scale and periodic nanopatterns. The nanopatterns designed within a two-dimensional polar chart can be carefully fabricated on the substrate. The fabricated patterns easily cover an area larger than 1 cm2, which is beneficial as platforms for surface enhanced infrared absorption (SEIRA) where an expensive and bulky IR microscope is not required. We believe that the proposed A-NLL method is ideal for industrialization of future nanophotonic applications.

Gold over Branched Palladium Nanostructures for Photothermal Cancer Therapy.

Bimetallic nanostructures show exciting potential as materials for effective photothermal hyperthermia therapy. We report the seed-mediated synthesis of palladium-gold (Pd-Au) nanostructures containing multiple gold nanocrystals on highly branched palladium seeds. The nanostructures were synthesized via the addition of a gold precursor to a palladium seed solution in the presence of oleylamine, which acts as both a reducing and a stabilizing agent. The interaction and the electronic coupling between gold nanocrystals and between palladium and gold broadened and red-shifted the localized surface plasmon resonance absorption maximum of the gold nanocrystals into the near-infrared region, to give enhanced suitability for photothermal hyperthermia therapy. Pd-Au heterostructures irradiated with an 808 nm laser light caused destruction of HeLa cancer cells in vitro, as well as complete destruction of tumor xenographs in mouse models in vivo for effective photothermal hyperthermia.

Oligonucleotides--assembled Au nanorod-assisted cancer photothermal ablation and combination chemotherapy with targeted dual-drug delivery of Doxorubicin and Cisplatin prodrug.

External stimuli responsive dual drugs carrier was synthesized with Au nanorods (NRs) as the platform. On Au NRs, single stranded DNAs were assembled using 5' thiol end. Following this, complementary DNA (cDNA) strands were hybridized. This hybridized double stranded DNA facilitated doxorubicin (Dox) intercalation into the duplexes. The cDNA designed with the 5' amine functional group assisted to tether platinum [Pt(IV)] prodrugs by establishing amide bond with the acid group at the axial ligand. The other axial acid group in Pt(IV) prodrugs was conjugated with the folic acid (FA) to target folate receptors overexpressed in the cancer cells. This targeting vehicle provided remote-controlled delivery of this high toxic cargo cocktail at the tumor site, ensuring extra specificity that can avoid acute toxicity, where release of Dox and Pt(IV) was achieved upon NIR 808 nm diode laser irradiation. The dehybridization set the Dox free to bind the cell nucleus and cellular reductants reduced Pt(IV) to yield toxic Pt(II), becoming an active drug. The in vitro and in vivo studies revealed that this external stimulus responsive combination drug delivery was significantly effective.

Near-infrared light photocontrolled targeting, bioimaging, and chemotherapy with caged upconversion nanoparticles in vitro and in vivo.

The major challenge in current chemotherapy is to increase local effective therapeutic concentration of drugs as well as to minimize toxicity and side effects for patients. The targeted delivery of drugs to their desired site of action in a controlled manner plays an essential role in the development of drug formulations. A photocage refers to a caged molecule rendered biologically inert by a photolabile protecting group. Molecules are illuminated with light to liberate the caged group and then become active forms. In this study, we formulate upconversion nanoparticles (UCNPs) as the NIR-triggered targeting and drug delivery vehicles that successfully deliver in vitro and in vivo for near-infrared light photocontrolled targeting, bioimaging, and chemotherapy. It is noted that there has been no report on the systemic administration UCNP-based drug delivery agents for evaluation of bioimaging and chemotherapy. To achieve phototargeting, the tumor-homing agent (i.e., folic acid) has been constructed as a photoresponsive molecule. For the chemotherapeutic effect, the antitumor drug doxorubicin is thiolated on the surface of UCNPs, forming a disulfide bond that can be cleaved by lysosomal enzymes within the cells. The caged UNCPs can serve as a platform for the improvement of selective targeting and possible reduction of adverse side effects from chemotherapy.

Tumor targeting and MR imaging with lipophilic cyanine-mediated near-infrared responsive porous Gd silicate nanoparticles.

We synthesize a NIR MHI-148 dye, a lipophilic heptamethine cyanine, with capability in tumor-targeting property to accumulate in the mitochondria of tumor. In the context of MHI-148 dye, we demonstrate effective tumor targeting and NIR fluorescence in vitro and in vivo for MHI-148 as compared to ICG. A series of porous Gd silicates related nanoparticles, i.e. Gd silicate, Gd silicate@mSiO(2) (mSiO(2): mesoporous silica shell), and Gd(3+)-chelated Gd silicate@mSiO(2) (Gd(3+)-DOTA chelated on the mSiO(2)) are fabricated to demonstrate their magnetic resonance (MR) contrast imaging effects. Those Gd silicates related nanoparticles exhibit dual MR effect, expressing T(1)-brightened and T(2)-darkened effects, in lower magnetic field. In high magnetic field, an abnormal enhanced transverse relaxivity (r(2)) appears, showing an effective T(2)-lowering effect, possibly due to concentrated Gd amount and porous architecture. The r(2) value increases 4-5 times as the field strength increased from 3T to 7T. The Gd(3+)-chelated Gd silicate@mSiO(2) has given large r(2) (T(2)-lowering effect) up to 343.8 s(-1) mM(-1), which is even larger than the reported magnetic Fe(3)O(4) nanoparticles measured at the same field. Using a 9.4T animal micro MRI system we have seen effectively darken in signal for those porous Gd silicates related NPs, while no such phenomenon appears in commercial Gd-DOTA agent. The MHI-148 is then conjugated on the porous Gd silicate@mSiO(2) nanoparticles for a new paradigm with three functionalities for in vivo tumor targeting, near-infrared fluorescent and MR imaging by means of only using MHI-148 dye.

Escape from the destruction of the galvanic replacement reaction for solid → hollow → solid conversion process in one pot reaction.

Based on the difference in the redox potentials between two metal species, the galvanic replacement reaction is known to create an irreversible process to generate hollow nanostructures in a wide range of shapes. In the context of galvanic replacement reaction, continuing etching leads to the general collapse of the hollow structures because of the excess amount of oxidizing agent. We demonstrate the growth of solid nanostructures from a hollow frame-like architecture in the course of a galvanic replacement reaction without any morphology destruction. We report the successful composition transformation of solid Ag with a wide range of shapes, such as plate, decahedron, rod, prism, sphere, and foil, from as thin as <10 nm up to 5 µm and with an area of ∼4 mm(2), to their solid Au counterparts using straightforward chemical reactions. The successful conversion process relies on a decrease in the reduction rate of the metallic precursor to initiate dissolution of Ag in the first stage (a galvanic replacement reaction), then a subsequent backfilling of Au into the hollowed-out structures. Cetyltrimethylammonium bromide (CTAB) surfactant, a key parameter, interacts with metal salt precursor to form a complex species that retards metal reduction. In addition, we demonstrate conversion of solid nano-Ag to solid nano-Pd as well as of Cu foil (10 µm thick) to shiny Au foil.