Dual Nanoparticles Research Articles

Synthesis and properties of YSZ and CeO2 dual nanoparticles doped Ni–B matrix nanocomposite coating

In this work, a novel yttria-stabilized zirconia (YSZ) and CeO2 dual nanoparticles doped Ni–B matrix nanocomposite coating has been fabricated by pulse current electrodeposition route. The effect of electrodeposition parameters on its structure, surface properties, corrosion and wear behaviors were evaluated. The nanocomposite coatings are compact with nodular-like morphology. The roughness is reduced with the increase of duty cycle. The average roughness (Sa) was about 28–46 nm and the duty cycle of 70% benefits low roughness and fine-grained structure. The crystallite sizes are 10–15 nm. Crystallite size is more dependent on current density compared to duty cycle and frequency. The coating exhibits a nanocrystalline structure with the preferred orientation of Ni (111) texture. The phase composition and preferred orientation is independent of duty cycle and frequency, but more dependent on current density. AFM and XPS were utilized to analyze the surface properties. EIS and wear test results indicated that the electrodeposition parameters greatly affect its corrosion and wear resistance. Duty cycle of 30% and 90%, current density of 2 A dm−2, frequency of 500–1500 Hz were the optimal parameters for the best corrosion resistance and better electrochemical stability in the long-term service in 3.5 wt% NaCl media.

A simple strategy to design 3-layered Au-TiO2 dual nanoparticles immobilized cellulose membranes with enhanced photocatalytic activity

Cellulose-based photocatalysts of supported nanoparticles feature high photocatalytic activity but their facile construction and photocatalytic mechanism exploration are highly challenging. Herein, a simple structural design principle and synergistic properties of 3-layered porous cellulose-based membranes are used for catalytic degradation of Rhodamine B in an aqua system. The 3-layered Au-TiO2 cellulose membranes were fabricated through the tape method and the suction filtration process. The composite membranes with strong redox ability, high charge-separation efficiency, and wide absorption range could stimulate the solar-driven plasma evaporation of Au nanoparticles and the photocatalytic function of TiO2 nanoparticles simultaneously. As characterized by Scanning Electron Microscopy, well-defined Au nanoparticles with an average size of 18.24 ± 3.17 nm were uniformly distributed on the TiO2-CM surface. Compared with TiO2-CM, TiO2-Au-CM showed better catalytic degradation of organic dye. This work demonstrated that a simple strategy design of Au-TiO2-CM could efficiently enhance the photocatalytic activity for the degradation of dyes in water.

Dual pH-responsive “charge-reversal like” gold nanoparticles to enhance tumor retention for chemo-radiotherapy

The strategy of pH-responsive aggregation in tumor micro-environment (TME) provides an intriguing platform for enhancing tumor retention and exerting therapeutic effects sufficiently. In this work, we have designed an intelligent dual pH-responsive self-aggregating nano gold system (Au@PAH-Pt/DMMA) for the combined chemo-radiotherapy, in which a “charge-reversal like” strategy was utilized to realize irreversible stable aggregation and pH-specific release of cisplatin prodrug in TME. Responsive aggregation increases the cellular uptake of Au@PAH-Pt/DMMA by 55%–60%, and the cellular uptake of Pt after X-ray irradiation can be further enhanced by 80%. Additionally, responsive aggregation greatly slows down the rate of efflux from tumor in vivo. This system not only promotes B16 cell apoptosis as a chemotherapeutic agent (30.4%), it also enhances the effect of chemo-radiotheray (CRT) by promoting apoptosis as a radiosensitizer (55.3%). The colony formation assay results were fitted to cell survival curve of B16 cells and the sensitization enhancement ratio (SER) was calculated to be 1.29, which shows a good radiosensitizing ability. When exposed to X-ray, this nanoplatform reached the ideal therapeutic effect, and the tumor inhibition rate of Au@PAH-Pt/DMMA reached 91.6% with low drug administration frequency and dose of X-ray. Overall, the dual pH-responsive nanoparticles Au@PAH-Pt/DMMA could effectively enhance tumor therapeutic efficiency by combined chemo-radiotherapy, which provides a potential method for clinical transformation of cancer treatment.

Dual red-NIR luminescent Eu Yb heterolanthanide nanoparticles as promising basis for cellular imaging and sensing

The present work introduces ternary Ln(III) (Ln = Eu, Yb, Lu) complexes with thenoyltriflouro1,3-diketonate (TTA-) and phosphine oxide derivative (PhO) as building blocks for core-shell nanoparticles with both Eu(III)- or Yb(III)-centered luminescence and the dual Eu(III)-Yb(III)-centered luminescence. Solvent-mediated self-assembly of the complexes is presented herein as the procedure for formation of EuLu, EuYb and YbLu heterometallic or homometallic cores coated by hydrophilic polystyrenesulfonate-based shells. Steady state and time resolved Eu-centered luminescence in homolanthanide and heterolanthanide EuLu and EuYb cores is affected by Eu → Eu and Eu → Yb energy transfer due to a close proximity of the lanthanide blocks within the core of nanoparticles. The Eu → Yb energy transfer is highlighted to be the reason for the enhancement of the NIR Yb-centered luminescence. Efficient cellular uptake, low cytotoxicity towards normal and cancer cells, and sensing ability of EuYb nanoparticles on lomefloxacin additives via both red and NIR channels make them promising as cellular imaging agents and sensors.

Co-Delivery of Natural Compounds with a Dual-Targeted Nanoparticle Delivery System for Improving Synergistic Therapy in an Orthotopic Tumor Model.

Various natural compounds including epigallocatechin gallate (EGCG) and curcumin (CU) have potential in developing anticancer therapy. However, their clinical use is commonly limited by instability and low tissue distribution. EGCG and CU combined treatment can improve the efficacy with synergistic effects. To improve the synergistic effect and overcome the limitations of low tissue distribution, we applied a dual cancer-targeted nanoparticle system to co-deliver EGCG and CU. Nanoparticles were composed of hyaluronic acid, fucoidan, and poly(ethylene glycol)-gelatin to encapsulate EGCG and CU. Furthermore, a dual targeting system was established with hyaluronic acid and fucoidan, which were used as agents for targeting CD44 on prostate cancer cells and P-selectin in tumor vasculature, respectively. Their effect and efficacy were investigated in prostate cancer cells and a orthotopic prostate tumor model. The EGCG/CU-loaded nanoparticles bound to prostate cancer cells, which were uptaken more into cells, leading to a better anticancer efficiency compared to the EGCG/CU combination solution. In addition, the releases of EGCG and CU were regulated by their pH value that avoided the premature release. In mice, treatment of the cancer-targeted EGCG/CU-loaded nanoparticles significantly attenuated the orthotopic tumor growth without inducing organ injuries. Overall, the dual-targeted nanoparticle system for the co-delivery of EGCG and CU greatly improved its synergistic effect in cancer therapy, indicating its great potential in developing treatments for prostate cancer therapy.

PH/redox dual response nanoparticles with poly-γ-glutamic acid for enhanced intracellular drug delivery

Stimuli-responsive nanomaterials drug delivery systems have attracted much attention owing to the ability to deliver drugs to designated locations especially for tumor cells. Here, positively and negatively charged pH/redox dual stimuli-responsive nanoparticles (NPs) were prepared with biocompatible poly-γ-glutamic acid (γ-PGA), cysteine (Cys), and chitosan (CS) through amide bond and electrostatic interactions. These nanocarriers (γ-PGA-S-S-CS NPs) were used to load the anticancer drug doxorubicin (DOX) to reduce toxicity to normal cells and increase uptake by tumor cells. The drug-loaded nanoparticles γ-PGA-S-S-CS-DOX NPs were characterized via DLS, XRD, FT-IR and TEM techniques. The DOX was released from γ-PGA-S-S-CS-DOX NPs under an acidic and redox environment, while the nanoparticles were kept stable under physiological conditions. in vitro cytotoxicity studies showed that the drug carriers do not impair the growth of cells, and cellular uptake experiments indicated that the drug-loaded NPs were taken up easily by tumor cells compared with the free drug. The results suggested that the dual response nanosystem carrier can be applied to the targeted delivery of other drugs in the cancer field.

Strengthening and Mechanical Properties of SiC and Graphite Reinforced Al6061 Hybrid Nanocomposites Processed Through Ultrasonically Assisted Casting Technique

Al6061 alloy-based hybrid nanocomposites reinforced with 2wt% SiC and x wt% of graphite (x = 0, 0.5, 1, 1.5, 2 and 3) nanoparticles are fabricated through ultrasonically assisted casting technique. Microstructure, phases, grain size and fracture surfaces of the hybrid nanocomposites are studied to understand the mechanical properties. Microstructural studies revealed the uniform distribution of SiC and graphite nano-reinforcements in the matrix. The small-scale clusters appeared in the microstructure with the increase in graphite nanoparticles. The grain size, density, hardness and ultimate tensile strength of hybrid nanocomposites decreased with the rise of graphite in the composite material. The yield strength of the hybrid nanocomposites increased with increase in graphite up to 2 wt% and then decreased. SiC and graphite dual phase nanoparticles’ strengthening effect on yield strength was theoretically evaluated using various strengthening mechanisms including porosity effect. Enhancement of yield strength in hybrid nanocomposite due to strengthening mechanisms followed the trend $$\Delta \sigma_{{\Delta {\text{CTE}}}} > \Delta \sigma_{\text{Orowan}} > \Delta \sigma_{\text{HP}} > \Delta \sigma_{\text{load}}$$ . The predicted yield strength of hybrid nanocomposites obtained using the modified Clyne model and quadratic summation model were close to the experimental values. Fracture surfaces of hybrid nanocomposites exhibited brittle fracture with interdendritic cracking, stepwise facets and particle pull out with the increase in graphite content in the matrix.

Direct quantification of cancerous exosomes via surface plasmon resonance with dual gold nanoparticle-assisted signal amplification

Sensitive detection of cancerous exosomes is critical to early diseases diagnosis and prognosis. Herein, a sensitive aptasensor was demonstrated for exosomes detection by surface plasmon resonance (SPR) with dual gold nanoparticle (AuNP)-assisted signal amplification. Dual nanoparticle amplification was achieved by controlled hybridization attachment of AuNPs resulting from electronic coupling between the Au film and AuNPs, as well as coupling effects in plasmonic nanostructures. By blocking the Au film surface with 11-Mercapto-1 -undecanol (MCU), nonspecific adsorption of AuNPs onto the SPR chip surface was suppressed and regeneration of the SPR sensor was realized. This method was highly sensitive and we have achieved the limit of detection (LOD) down to 5 × 103 exosomes/mL, which showed a 104-fold improvement in LOD compared to commercial ELISA. Moreover, the SPR sensor had the capability to differentiate the exosomes secreted by MCF-7 breast cancer cells and MCF-10A normal breast cells. Furthermore, the SPR sensor could effectively detect the exosomes in 30% fetal bovine serum. The work provides a sensitive and efficient quantification approach to detect cancerous exosomes and offers an avenue toward future diagnosis and comprehensive studies of exosomes.

CO2/NIR light dual-controlled nanoparticles for dsDNA unzipping

Both of carbon dioxide (CO2) and near-infrared (NIR) light as triggers for non-invasive remotely control are attracting wide attentions due to their good biocompatibility and easy operation. Here, CO2/NIR light dual controlled nanoparticles are proposed to remotely regulate the unzipping of dsDNA by using imidazole functionalized conjugated polymer nanoparticles (imidazole-CPNs). The dsDNA successfully coats on the shell of imidazole-CPNs to form imidazole-CPNs/dsDNA assembly due to intensively electrostatic interaction triggered by CO2. Furthermore, the unzipping process of dsDNA is remotely controlled by NIR light based on the photothermal effect, and it can be readily monitored by the fluorescence intensity of ethidium bromide (EB) and CD spectra of dsDNA. Thus, dual stimulation responsive imidazole-CPNs effectively control dsDNA unzipping under CO2 stimulus and NIR light, promising a new direction in the biological applications of DNA, such as the treatments of diseases caused by gene duplication abnormality.

Silica nanoparticles with dual visible–NIR luminescence affected by silica confinement of Tb(III) and Yb(III) complexes for cellular imaging application

The work introduces silica confinement of Tb(III) and Yb(III) complexes with p-sulfonatothiacalix[4]arene (TCAS) arisen from their doping into silica nanoparticles (51–60 nm) as the reason for efficient dual green–NIR luminescence. pH-regulated water solubility of the lanthanide complexes is highlighted as prerequisite for the balance between efficient doping of the complexes into silica nanoparticles and their size/shape university. The impact of Tb(III) → Yb(III) energy transfer on the NIR and visible luminescence of the nanoparticles was revealed from photophysical studies of the nanoparticles doped with different couples of lanthanide complexes (Tb–Gd, Tb–Yb, Yb–Gd) at various molar ratios. The optimal balance between green and NIR luminescence is achieved for the silica nanoparticles doped with Tb–Yb complexes at 2:1 (Tb:Yb) ratio due to both Tb(III) → Yb(III) energy transfer and specific distribution of Tb(III) and Yb(III) complexes within silica nanoparticles. The dual luminescent nanoparticles exhibit efficient cellular uptake behavior after amino-decoration of their surface, which is confirmed by confocal microscopy images of the cells incubated by the heterometallic nanoparticles.

Signal-Enhanced Lateral Flow Immunoassay with Dual Gold Nanoparticle Conjugates for the Detection of Hepatitis B Surface Antigen

We developed a signal-enhanced lateral flow immunoassay based on dual gold nanoparticle conjugates for the determination of hepatitis B surface antigen, in which no additional operation step for si...

Colorimetric detection and typing of E. coli lipopolysaccharides based on adual aptamer-functionalized gold nanoparticle probe.

A rapid method for identification and typing of lipopolysaccharides (LPS) was developed by utilizing the different binding affinities between two kinds of gold nanoparticles (AuNPs) functionalized with two aptamers. Aptamers against ethanolamine and E. coli O111:B4 LPS were used to functionalize the AuNPs. The AuNPs functionalized with ethanolamine aptamer can bind to ethanolamine and are termed general probe (G-probe). The G-probe can recognize any type of LPS because ethanolamine is a component of every type of LPS. This causes a sandwich-mediated aggregation of the AuNPs and a color change from red to blue. The AuNPs functionalized with aptamer against the LPS of E. coli O111:B4 specifically bind to O111:B4 LPS and are termed specific probe (S-probe). By using these two probes, a logic typing method was developed. It can detect LPS in concentrations between 2.5 and 20μg·mL-1 and with a 1μg·mL-1 detection limit. In the authors' perception, the use of a dual aptamer-based colorimetric method has a large potential in terms of selective detection of microorganisms. Graphical abstract Two aptamer functionalized AuNP probes, G-probe and S-probe, were prepared for LPS typing and detecting. E. coli O111:B4 LPS was easily distinguished from O55:B5 LPS according to the signal output configurations (On & On Vs On & Off) of a general probe (G-probe) and a specific probe (S-probe).

A novel Mn/Co dual nanoparticle decorated hierarchical carbon structure derived from a biopolymer hydrogel as a highly efficient electro-catalyst for the oxygen reduction reaction.

A Mn/Co dual nanoparticle-decorated hierarchical carbon structure was derived from a Zn/Mn/Co/chitosan composite hydrogel. This strategy critically relied on the formation of a supramolecularly crosslinked hydrogel that allowed the efficient and homogeneous incorporation of highly active Mn/Co species onto the surface of hierarchical carbon structures. The resultant electrocatalyst outperformed Pt/C toward the oxygen reduction reaction in 0.1 M KOH electrolytes.

Enhanced fermentative hydrogen production from industrial wastewater using mixed culture bacteria incorporated with iron, nickel, and zinc-based nanoparticles

The present study assessed the efficiency of utilizing mixed culture bacteria (MCB) incorporated with individual nanoparticles (NPs), i.e., hematite (α-Fe2O3), nickel oxide (NiO), and zinc oxide (ZnO), dual NPs (α-Fe2O3 + NiO, α-Fe2O3 + ZnO, and NiO + ZnO), and multi-NPs (α-Fe2O3 + NiO + ZnO) for hydrogen production (HP) from industrial wastewater containing mono-ethylene glycol (MEG). When MCB was individually supplemented with α-Fe2O3 (200 mg/L), NiO (20 mg/L), and ZnO NPs (10 mg/L), HP improved significantly by 41, 30, and 29%, respectively. Further, key enzymes associated with MEG metabolism, such as alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and hydrogenase (hyd), were rapidly and substantially enhanced in the medium. NiO and ZnO NPs notably promoted ADH and ALDH activities, respectively, while α-Fe2O3 exhibited superior impact on hyd activity. Maximum hydrogen production rate was concomitant with higher acetic acid production and lower residual acetaldehyde and ethanol. HP using MCB supplemented with individual NiO (20 mg/L) and ZnO NPs (10 mg/L) further improved by 8.0%–14% when dual and multi-NPs were used; the highest HP was recorded when multi-NPs were used. In addition, NPs incorporation resulted in substantial increase in the relative abundance of Clostridiales (belonging to family Clostridiaceae; > 83%). Overall, this study provides significant insights into the impact of NPs on hydrogen production from MEG-contaminated wastewater.

Radiolabeling and Biodistribution of new dual modality nanoparticle probe in Nuclear Medicine

Introduction: Dual-modality contrast agents, such as radiolabeled nanoparticles, are promising candidates for a number of diagnostic applications, namely SPECT imaging with MR imaging. So the aim of study was evaluating potential of Chitosan-Coated Magnetic Nanoparticles(SPION) labeled with 99mTc as new Dual-modality probes for liver Imaging. Materials and Methods: In this study chitosan particles were coated on SPION and radiolabeled with 99mTc after Purification. The quality control tests including determining particles size, labeling efficiency, stability and Biodistribution study in the mice were performed. Finally MRI and nuclear medicine imaging study in Balb/c mice in 1 and 4 hour after injection of complex were performed. Results: Results showed that the final complex have spherical shape and with average size 255±30nm. The labeling efficiency and stability of complex with 99mTc were 89±6%, 93±6% respectively. Biodistribution study, MRI and nuclear medicine imaging showed high accumulation of Complex in liver. Conclusion: The results showed that the 99mTc-Chitosan coated SPION may be considered as promising Dual-modality probes for liver Imaging.

Unidirectional optical nanoantenna with individual core–dual shells nanoparticle

We propose an optical nanoantenna, which is an individual nanosphere consisting of two identical metal strips separated by a dielectric spacer (Ag–Ge–Ag) with a notch. Such design integrates the advantages of array dielectric antenna and plasmonic antenna such as high directivity, emission direction control, and highly localized field enhancement based on excitation of electric and magnetic multipoles of high-orders and localized surface plasmons in the symmetry breaking of this nanomatryoshka. Major properties of this nanoantenna have been revealed theoretically and numerically. We compare our hybrid nanoantenna with plasmonic and dielectric nanoantenna of similar geometry, and the proposed nanoantenna exhibits better directivity and efficiency. By suitably positioning the feed inside the notch, this compact nanoantenna can spectrally sort the electromagnetic emission, together with a high value in directivity up to 13.5. In addition, we have also revealed that displacement of the emitter along the y-axis leads to beam rotation. In contrast to other conventional nanoantenna in subwavelength, the proposed nanoantenna may exhibit higher directivity and Purcell factor due to effective excitation of electric and magnetic multipoles of high-orders inside the nanoparticle and localized surface plasmons in the outmost metal shell. The ultradirectional nanoantenna may shed light to the design of compact nanoantennas, which may find various applications in biosensing and quantum communications.

A Bacteriophage T4 Nanoparticle-Based Dual Vaccine against Anthrax and Plague.

Bacillus anthracis and Yersinia pestis, the causative agents of anthrax and plague, respectively, are two of the deadliest pathogenic bacteria that have been used as biological warfare agents. Although Biothrax is a licensed vaccine against anthrax, no Food and Drug Administration-approved vaccine exists for plague. Here, we report the development of a dual anthrax-plague nanoparticle vaccine employing bacteriophage (phage) T4 as a platform. Using an in vitro assembly system, the 120- by 86-nm heads (capsids) of phage T4 were arrayed with anthrax and plague antigens fused to the small outer capsid protein Soc (9 kDa). The antigens included the anthrax protective antigen (PA) (83 kDa) and the mutated (mut) capsular antigen F1 and the low-calcium-response V antigen of the type 3 secretion system from Y. pestis (F1mutV) (56 kDa). These viral nanoparticles elicited robust anthrax- and plague-specific immune responses and provided complete protection against inhalational anthrax and/or pneumonic plague in three animal challenge models, namely, mice, rats, and rabbits. Protection was demonstrated even when the animals were simultaneously challenged with lethal doses of both anthrax lethal toxin and Y. pestis CO92 bacteria. Unlike the traditional subunit vaccines, the phage T4 vaccine uses a highly stable nanoparticle scaffold, provides multivalency, requires no adjuvant, and elicits broad T-helper 1 and 2 immune responses that are essential for complete clearance of bacteria during infection. Therefore, phage T4 is a unique nanoparticle platform to formulate multivalent vaccines against high-risk pathogens for national preparedness against potential bioterror attacks and emerging infections.IMPORTANCE Following the deadly anthrax attacks of 2001, the Centers for Disease Control and Prevention (CDC) determined that Bacillus anthracis and Yersinia pestis that cause anthrax and plague, respectively, are two Tier 1 select agents that pose the greatest threat to the national security of the United States. Both cause rapid death, in 3 to 6 days, of exposed individuals. We engineered a virus nanoparticle vaccine using bacteriophage T4 by incorporating key antigens of both B. anthracis and Y. pestis into one formulation. Two doses of this vaccine provided complete protection against both inhalational anthrax and pneumonic plague in animal models. This dual anthrax-plague vaccine is a strong candidate for stockpiling against a potential bioterror attack involving either one or both of these biothreat agents. Further, our results establish the T4 nanoparticle as a novel platform to develop multivalent vaccines against pathogens of high public health significance.

Loading studies of the anticancer drug camptothecin into dual stimuli-sensitive nanoparticles. Stability scrutiny

In recent years, the preparation of valuable drug delivery systems (DDS) from self-assembled amphiphilic copolymers has attracted much attention since these nanomaterials provide new opportunities to solve problems such as the lack of solubility in water of lipophilic drugs, improve their bioavailability, prolong their circulation time and decrease the side effects associated with their administration. In the current study two types of biocompatible pH-responsive nanoparticles derived from poly(2-hydroxyethyl methacrylate) (pHEMA) have been used as drug nano-carriers, being one of them core cross-linked to circumvent their instability upon dilution in human fluids. The present paper deals with the optimization of the loading process of the labile, hydrophobic and highly active anticancer drug, Camptothecin (CPT) into the nanoparticles with regard to four independent variables: CPT/polymer ratio, sonication, temperature and loading time. Forty experiments were carried out and a Box–Behnken experimental design was used to evaluate the significance of the independent variables related to encapsulation efficiency and drug retention capacity. The enhanced drug loading and encapsulation efficiency values (58% and >92%, respectively) of CPT were achieved by the core cross-linked NPs in 2 h at 32 °C at CPT/polymer ratio 1.5:1 w/w and 14 min of sonication. The optimized CPT-loaded NPs were studied by dynamic light scattering and scanning electron microscopy, and an increase in size of the loaded-NP compared to the unloaded counterparts was found. Other twenty experiments were conducted to study the enability to retain CPT into the conjugates at different ionic strength values and times. The stability studies demonstrated that the core cross-linked nanocarriers displayed an excellent drug retention capacity (>90%) at 25 °C for 15 days in every ionic-strength environments whereas the non-cross-linked ones were more stable at physiological ionic strength. The optimized systems proved to be a major step forward to encapsulate and retain CPT in the NP nuclei, what makes them ideal devices to control the delivery of CPT upon the triggered acidic conditions of solid tumors.

An ultrasensitive signal-on electrochemical aptasensor for ochratoxin A determination based on DNA controlled layer-by-layer assembly of dual gold nanoparticle conjugates

In this paper, a novel ultrasensitive signal-on electrochemical aptasensor has been proposed for Ochratoxin A (OTA) assay based on DNA controlled layer-by-layer assembly of dual gold nanoparticle (AuNP) conjugates. To construct the aptasensor, the 1st AuNP conjugate was prepared by simultaneous immobilization of the capture probe 2 (CP2) and bridge probe (BP) onto the AuNPs. Then, OTA aptamer was loaded onto 1st AuNPs by hybridization with CP2. The 1st AuNP conjugate can be further immobilized onto the electrode by hybridization between BP and capture probe 1 (CP1), which was pre-immobilized on Au electrode. The 2nd AuNP conjugate was prepared by immobilization of ferrocene (Fc) tagged SH-signal probe (SSP). Due to the recognition between aptamer on 1st AuNP conjugate and OTA, CP2 was reformed in the ssDNA state, which can be utilized as the anchor for immobilization of 2nd AuNP conjugate for electrochemical signal reporting. Because of the high surface-to-volume ratio and good conductivity of AuNPs, this dual AuNPs assembled nanoarchitecture finally lead to greatly improved abilities to load a large number of Fc molecules and significantly amply the electrochemical response even at a low target concentration. Both qualitative and quantitative analysis of OTA were thus realized by differential pulse voltammetry (DPV) signals, resulting in an excellent detection limit of 0.001 ppb and a wide dynamic range from 0.001 to 500 ppb over 6 orders of magnitude. Moreover, the real sample analysis towards OTA spiked wine samples was favorable, implying a great potential for practical applications. We envision that this unique dual AuNP conjugate assembly strategy would pave a new avenue for the development of versatile signal amplified electrochemical aptasensors.

Dual stimuli-responsive polypyrrole nanoparticles for anticancer therapy

We report the development of dual stimuli-responsive nanoparticles with potential for anticancer therapy. The nanoparticles are composed of a conjugated polymer (polypyrrole, PPY) loaded with an anticancer drug (allicin), and were characterized by a variety of physicochemical techniques. The dual stimuli-responsive nature of the PPY nanoparticles was validated in vitro: the PPY nanoparticles delivered an anticancer drug (allicin) in response to exposure to an electric field in vitro as demonstrated with UV–vis spectroscopy; and the PPY nanoparticles exhibited photothermal activity upon irradiation with near infrared light which resulted in resulted in toxicity towards HEP G2 cells in vitro. We believe that such nanoparticles have long term potential for application in cancer therapy in a variety of tissue niches (e.g. breast cancer, liver cancer, lung cancer, skin cancer).