S-Nitrosocysteine-Decorated PbS QDs/TiO2 Nanotubes for Enhanced Production of Singlet Oxygen

pH/GSH dual responsive nanosystem for nitric oxide generation enhanced type I photodynamic therapy

Tumor hypoxia diminishes the effectiveness of traditional type II photodynamic therapy (PDT) due to oxygen consumption. Type I PDT, which can operate independently of oxygen, is a viable option for treating hypoxic tumors. In this study, we have designed and synthesized JSK@PEG-IR820 NPs that are responsive to the tumor microenvironment (TME) to enhance type I PDT through glutathione (GSH) depletion. Our approach aims to expand the sources of therapeutic benefits by promoting the generation of superoxide radicals (O2-.) while minimizing their consumption. The diisopropyl group within PEG-IR820 serves a dual purpose: it functions as a pH sensor for the disassembly of the NPs to release JSK and enhances intermolecular electron transfer to IR820, facilitating efficient O2-. generation. Simultaneously, the release of JSK leads to GSH depletion, resulting in the generation of nitric oxide (NO). This, in turn, contributes to the formation of highly cytotoxic peroxynitrite (ONOO-.), thereby enhancing the therapeutic efficacy of these NPs. NIR-II fluorescence imaging guided therapy has achieved successful tumor eradication with the assistance of laser therapy.

Theranostics applications of quantum dots in regenerative medicine, cancer medicine, and infectious diseases

Quantum dots (QDs) have attracted attention for their application and commercialization in all industrial fields, including communications, displays, and solar cells, due to their excellent optical properties based on the quantum size effect. In recent years, the development of QDs that do not contain cadmium which is toxic to cells and living organisms, has progressed, and they have attracted considerable attention in the bio-imaging field for targeting molecules and cells. Furthermore, recently, the need for diagnostics and treatment at the single molecule and single cell level in the medical field has been increasing, and the application of QDs in the medical field is also accelerating. Therefore, this paper outlines the frontiers of diagnostic and therapeutic applications (theranostics) of QDs, especially in advanced medical fields such as regenerative medicine, oncology, and infectious diseases.

Recent Advances in Functional Nanomaterials for Catalytic Generation of Nitric Oxide: A Mini Review

As a gaseous second messenger, nitric oxide (NO) plays an important role in a series of signal pathways. Research on the NO regulation for various disease treatments has aroused wide concern. However, the lack of accurate, controllable, and persistent release of NO has significantly limited the application of NO therapy. Profiting from the booming development of advanced nanotechnology, a mass of nanomaterials with the properties of controllable release have been developed to seek new and effective NO nano-delivery approaches. Nano-delivery systems that generate NO through catalytic reactions exhibit unique superiority in terms of precise and persistent release of NO. Although certain achievements have been made in the catalytically active NO delivery nanomaterials, some basic but critical issues, such as the concept of design, are of low attention. Herein, an overview of the generation of NO through catalytic reactions and the design principles of related nanomaterials are summarized. Then, the nanomaterials that generate NO through catalytic reactions are classified. Finally, the bottlenecks and perspectives are also discussed in depth for the future development of catalytical NO generation nanomaterials.

Quantum Dot-Based Micromotors with NIR-I Light Photocatalytic Propulsion and NIR-II Fluorescence

Here, we report the first PbS quantum dot (QD)-based micromotors with NIR-I light-driven photocatalytic propulsion and NIR-II fluorescence. Under the irradiation of NIR-I light (808 nm), PbS QD-doped cuprous oxide (Cu₂O@PbS) micromotors can display efficient propulsion in a variety of biocompatible fuels such as malic acid, glucose, and urea. Among them, the Cu₂O@PbS micromotors exhibit the best propulsion performance in a very low concentration of malic acid, with an average speed as high as 11.86 μm/s. The enhanced NIR-I photocatalytic activity of Cu₂O@PbS micromotors benefits from the doping of NIR-I PbS QDs that can be excited by NIR-I light and exhibit high electron transport efficiency. The doped PbS QDs can effectively increase the absorption efficiency of the micromotors in the NIR-I region while also inhibiting the recombination of photogenerated electron-hole pairs. Interestingly, due to the presence of NIR PbS QDs, the Cu₂O@PbS micromotors demonstrate prominent and stable NIR-II fluorescence (emission wavelength: 1100 nm), which offer promising potential for visualization of their position in vivo. In comparison to other photocatalytic micromotors, the simple fabrication strategy, excellent NIR-II fluorescence, together with the NIR-I light-dependent propulsion behavior of the current Cu₂O@PbS micromotors, thus pave the way for further development of advanced smart "robots" for intelligent biomedical applications.

Photoelectrochemical Enzyme Biosensor Based on TiO2 Nanorod/TiO2 Quantum Dot/Polydopamine/Glucose Oxidase Composites with Strong Visible-Light Response

Although photoelectrochemical (PEC) enzyme biosensors based on visible-light detection would have a high practical value, their development has been limited by the weak visible-light response of available photoactive substrates. Here, to enhance the visible-light response of a photoelectric substrate, a TiO₂ nanorods (NRs)/TiO₂ quantum dots (QDs)/polydopamine (PDA)/glucose oxidase nanocomposite was prepared via hydrothermal synthesis, followed by photopolymerization. TiO₂ QDs with strong light absorption and excellent photocatalytic activity were introduced between the TiO₂ NRs and the PDA. An efficient electron transport interface that formed as a result of the combination of the TiO₂ NRs, TiO₂ QDs, and the PDA could not only transfer electrons quickly and orderly, but also substantially improve the response of the TiO₂ NRs under visible light. Through a series glucose detection, a sensor based on the nanocomposite was found to exhibit superior sensing performance under visible light with a sensitivity of 4.63 μA mM^-1 cm^-2, a linear response over the concentration 0.1-4 mM, and a detection limit of 8.16 μM. This work proposes a biosensor that can detect under visible light, thereby expanding the application range of PEC enzyme biosensors.

Advanced nitric oxide donors: chemical structure of NO drugs, NO nanomedicines and biomedical applications

Nitric oxide (NO), as an endogenous diatomic molecule, plays a key regulatory role in many physiological and pathological processes. This diatomic free radical has been shown to affect different physiological and cellular functions and participates in many regulatory functions ranging from changing the cardiovascular system to regulating neuronal functions. Thus, NO gas therapy as an emerging and promising treatment method has attracted increasing attention in the treatment of various pathological diseases. As is known, the physiological and pathological regulation of NO depends mainly on its location, exposure time and released dosage. However, NO gas lacks effective accumulation and controlled long-term gas releasing capacity at specific sites, resulting in limited therapeutic efficacy and potential side effects. Thus, researchers have developed various NO donors, but eventually found that it is still difficult to control the long-term release of NO. Inspired by the self-assembly properties of nanomaterials, researchers have realized that nanomaterials can be used to support NO donors to form nanomedicine to achieve spatial and temporal controlled release of NO. In this review, according to the history of the medicinal development of NO, we first summarize the chemical design of NO donors, NO prodrugs, and NO-conjugated drugs. Then, NO nanomedicines formed by various nanomaterials and NO donors depending on nanotechnology are highlighted. Finally, the biomedical applications of NO nanomedicine with optimized properties are summarized.

Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials

Photoactivatable (alternatively, photoremovable, photoreleasable, or photocleavable) protecting groups (PPGs), also known as caged or photocaged compounds, are used to enable non-invasive spatiotemporal photochemical control over the release of species of interest. Recent years have seen the development of PPGs activatable by biologically and chemically benign visible and near-infrared (NIR) light. These long-wavelength-absorbing moieties expand the applicability of this powerful method and its accessibility to non-specialist users. This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide). The text also covers visible- and NIR-light-induced photosensitized release using molecular sensitizers, quantum dots, and upconversion and second-harmonic nanoparticles, as well as release via photodynamic (photooxygenation by singlet oxygen) and photothermal effects. Release from photoactivatable polymers, micelles, vesicles, and photoswitches, along with the related emerging field of photopharmacology, is discussed at the end of the review.

A turn-on fluorescent nanoprobe based on N-doped silicon quantum dots for rapid determination of glyphosate

N-Doped silicon quantum dots (N-SiQD) were synthesized using N-[3-(trimethoxysily)propyl]-ethylenediamine and citric acid as silicon source and reduction agent, respectively. The N-SiQD shows a strong blue fluorescence with a high quantum yield of about 53%. It is found that a selective static quenching process occurs between N-SiQDs and Cu2+. Glyphosate can inhibit this phenomenon and trigger the rapid fluorescence enhancement of the quenched N-SiQDs/Cu2+ system due to the specific interaction between Cu2+ and glyphosate. With such a design, a turn-on fluorescent nanoprobe based on N-SiQD/Cu2+ system was established for rapid determination of glyphosate. The determination signal of N-SiQD/Cu2+ was measured at the optimum emission wavelength of 460 nm after excitation at 360 nm. Under optimal conditions, the turn-on nanoprobe showed a linear relationship between fluorescent response and glyphosate concentrations in the range 0.1 to 1 μg mL-1. The limit of determination was calculated to 7.8 ng mL-1 (3σ/S). Satisfactory recoveries were obtained in the determination of spiked water samples, indicating the potential use for environmental monitoring. Graphical abstract Schematic representation of N-SiQD/Cu2+ system for glyphosate determination. Fluorescence quenching of N-SiQDs induced by copper ions and the succedent fluorescent "turn on" triggered by glyphosate.

Ultrasensitive photoelectrochemical sensor enabled by a target-induced signal quencher release strategy

In this work, a target-induced signal quencher release strategy was proposed to construct a sensitive photoelectrochemical (PEC) sensor.

Nitric oxide and its derivatives in the cancer battlefield

Elevated levels of reactive nitrogen species, alteration in redox balance and deregulated redox signaling are common hallmarks of cancer progression and chemoresistance. However, depending on the cellular context, distinct reactive nitrogen species are also hypothesized to mediate cytotoxic activity and are thus used in anticancer therapies. We present here the dual face of nitric oxide and its derivatives in cancer biology. Main derivatives of nitric oxide, such as nitrogen dioxide and peroxynitrite cause cell death by inducing protein and lipid peroxidation and/or DNA damage. Moreover, they control the activity of important protein players within the pro- and anti-apoptotic signaling pathways. Thus, the control of intracellular reactive nitrogen species may become a sophisticated tool in anticancer strategies.

Exciton dissociation in an NIR-active triohybrid nanocrystal leading to efficient generation of reactive oxygen species

Lead sulfide (PbS) colloidal quantum dots (QDs) are emerging materials for fundamental studies because of their potential application in near infrared (NIR) light harvesting technologies. However, inefficient electron separation, facile charge recombination and defect state trapping of photoexcited carriers are reported as limitations of the PbS QDs to achieve efficient energy conversion. In the present study, we have synthesized a triohybrid by assembling a semiconductor titanium dioxide (TiO₂), an organic oxidizing molecule phenothiazine (PTZ) and PbS QDs. The triohybrid along with PbS_TiO₂ and PbS_PTZ hybrids has been characterized and the attachment of different components is verified by spectroscopic and microscopic techniques. The interfacial dynamics of the photoexcited carriers in the PbS_TiO₂ and PbS_PTZ hybrids have been investigated separately using steady state and time resolved photoluminescence (TRPL) measurements. The photoinduced electron transfer (PET) from the PbS QD to the conduction band (CB) of TiO₂ and photoinduced hole transfer (PHT) from the valence band (VB) of the QD to the highest occupied molecular orbital (HOMO) of PTZ have been observed and correlated mechanistically to the energy level alignments obtained from cyclic voltammetric (CV) analysis. The PTZ molecule is also found to act as a surface defect passivator of the PbS QD. Finally, simultaneous exciton dissociation and reduced back recombination phenomena have been correlated with a higher reactive oxygen species (ROS) generation activity of the triohybrid than the other two, under IR light irradiation. Thus, a detailed investigation of carrier dynamics and the mechanism of higher NIR light activity for a novel nanohybrid is explored and analyzed which could be beneficial for NIR catalysis or antibacterial activities.

Redox-responsive UCNPs-DPA conjugated NGO-PEG-BPEI-DOX for imaging-guided PTT and chemotherapy for cancer treatment

The disulfide bond (–S–S–) is an enormously valuable functional group in a variety of chemical and biological agents that display effective reactivity or biological activities (e.g., antitumor activities).

Controlled preparation of M(Ag, Au)/TiO2 through sulfydryl-assisted method for enhanced photocatalysis

Here a simple and effective method was explored to fabricate M/TiO₂ (M = Ag, Au) composites, which required neither pre-treatment of TiO₂ nor any additives as reducing agent. Using amorphous TiO₂ spheres functionalized with SH groups as starting materials, the noble metallic ions (Ag, Au) can be adsorbed by TiO₂ due to their special affinity with SH groups, which is beneficial to the uniform dispersion of metallic ions on the surface of TiO₂. Then the adsorbed ions were reduced to form noble metal nanoparticles by heating process (95 °C) directly without additive as reduction agent. Meanwhile, the amorphous TiO₂ was transformed into anatase phase during the heating process. Thus, the transformation of TiO₂ along with the reduction of noble metallic ions (Ag, Au) was simultaneously carried out by heating. The XRD patterns proved the formation of anatase TiO₂ after heating. The characterizations of XPS and TEM proved the formation of Ag and Au nanoparticles on the surface of TiO₂. The element mapping indicated that Ag nanoparticles are dispersed uniformly on the surface of TiO₂. The photocatalytic activity of the composites has been investigated by the degradation of methyl orange under visible light irradiation. The results showed that when Ag/TiO₂ (2.8 wt%) was used as photocatalyst, about 98% of the MO molecules were degraded in 70 min.

Uniform carbon dots@TiO2 nanotube arrays with full spectrum wavelength light activation for efficient dye degradation and overall water splitting

This work presents a novel approach for preparing photocatalysts based on TiO₂ nanotube arrays (TiO₂ NTAs) anchored with carbon dots (CDs) by a facile two-step method which includes an electrochemical anodization technique followed by electrochemical deposition. The synthesized high quality graphitic carbon dots can act as sensitizers to extend the spectral range of light absorption towards the full solar spectrum. It is confirmed that TiO₂ NTAs anchored with CDs (CDs/TiO₂ NTAs) display greatly improved photocatalytic activity and excellent photocatalytic stability. By tuning the light absorption of the TiO₂ NTAs, the utilization of light in charge generation and separation is well synergized with the CDs for enhanced photocatalytic pollutant degradation and water splitting, achieving significantly improved rates of photocatalytic degradation and H₂ production in the visible and full spectra, respectively.

Smart Nanostructures for Cargo Delivery: Uncaging and Activating by Light

Nanotechnology has begun to play a remarkable role in various fields of science and technology. In biomedical applications, nanoparticles have opened new horizons, especially for biosensing, targeted delivery of therapeutics, and so forth. Among drug delivery systems (DDSs), smart nanocarriers that respond to specific stimuli in their environment represent a growing field. Nanoplatforms that can be activated by an external application of light can be used for a wide variety of photoactivated therapies, especially light-triggered DDSs, relying on photoisomerization, photo-cross-linking/un-cross-linking, photoreduction, and so forth. In addition, light activation has potential in photodynamic therapy, photothermal therapy, radiotherapy, protected delivery of bioactive moieties, anticancer drug delivery systems, and theranostics (i.e., real-time monitoring and tracking combined with a therapeutic action to different diseases sites and organs). Combinations of these approaches can lead to enhanced and synergistic therapies, employing light as a trigger or for activation. Nonlinear light absorption mechanisms such as two-photon absorption and photon upconversion have been employed in the design of light-responsive DDSs. The integration of a light stimulus into dual/multiresponsive nanocarriers can provide spatiotemporal controlled delivery and release of therapeutic agents, targeted and controlled nanosystems, combined delivery of two or more agents, their on-demand release under specific conditions, and so forth. Overall, light-activated nanomedicines and DDSs are expected to provide more effective therapies against serious diseases such as cancers, inflammation, infections, and cardiovascular disease with reduced side effects and will open new doors toward the treatment of patients worldwide.

Sensitive arginine sensing based on inner filter effect of Au nanoparticles on the fluorescence of CdTe quantum dots

Arginine plays an important role in many biological functions, whose detection is very significant. Herein, a sensitive, simple and cost-effective fluorescent method for the detection of arginine has been developed based on the inner filter effect (IFE) of citrate-stabilized gold nanoparticles (AuNPs) on the fluorescence of thioglycolic acid-capped CdTe quantum dots (QDs). When citrate-stabilized AuNPs were mixed with thioglycolic acid-capped CdTe QDs, the fluorescence of CdTe QDs was significantly quenched by AuNPs via the IFE. With the presence of arginine, arginine could induce the aggregation and corresponding absorption spectra change of AuNPs, which then IFE-decreased fluorescence could gradually recover with increasing amounts of arginine, achieving fluorescence "turn on" sensing for arginine. The detection mechanism is clearly illustrated and various experimental conditions were also optimized. Under the optimum conditions, a decent linear relationship was obtained in the range from 16 to 121μgL^-1 and the limit of detection was 5.6μgL^-1. And satisfactory results were achieved in arginine analysis using arginine injection, compound amino acid injection, even blood plasma as samples. Therefore, the present assay showed various merits, such as simplicity, low cost, high sensitivity and selectivity, making it promising for sensing arginine in biological samples.

Micro/Nanoparticle-Augmented Sonodynamic Therapy (SDT): Breaking the Depth Shallow of Photoactivation

The fast development of photoactivation for cancer treatment provides an efficient photo-therapeutic strategy for cancer treatment, but traditional photodynamic or photothermal therapy suffers from the critical issue of low in vivo penetration depth of tissues. As a non-invasive therapeutic modality, sonodynamic therapy (SDT) can break the depth barrier of photoactivation because ultrasound has an intrinsically high tissue-penetration performance. Micro/nanoparticles can efficiently augment the SDT efficiency based on nanobiotechnology. The state-of-art of the representative achievements on micro/nanoparticle-enhanced SDT is summarized, and specific functions of micro/nanoparticles for SDT are discussed, from the different viewpoints of ultrasound medicine, material science and nanobiotechnology. Emphasis is put on the relationship of structure/composition-SDT performance of micro/nanoparticle-based sonosensitizers. Three types of micro/nanoparticle-augmented SDT are discussed, including organic and inorganic sonosensitizers and micro/nanoparticle-based but sonosensitizer-free strategies to enhance the SDT outcome. SDT-based synergistic cancer therapy augmented by micro/nanoparticles and their biosafety are also included. Some urgent critical issues and potential developments of micro/nanoparticle-augmented SDT for efficient cancer treatment are addressed. It is highly expected that micro/nanoparticle-augmented SDT will be quickly developed as a new and efficient therapeutic modality which will find practical applications in cancer treatment. At the same time, fundamental disciplines regarding materials science, chemistry, medicine and nanotechnology will be advanced.

Paper analytical devices for dynamic evaluation of cell surface N-glycan expression via a bimodal biosensor based on multibranched hybridization chain reaction amplification

A novel colorimetric/fluorescence bimodal lab-on-paper cyto-device was fabricated based on concanavalin A (Con A)-integrating multibranched hybridization chain reaction (mHCR). The product of mHCR was modified PtCu nanochains (colorimetric signal label) and graphene quantum dot (fluorescence signal label) for in situ and dynamically evaluating cell surface N-glycan expression. In this strategy, preliminary detection was carried out through colorimetric method, if needed, then the fluorescence method was applied for a precise determination. Au-Ag-paper devices increased the surface areas and active sites for immobilizing larger amount of aptamers, and then specifically and efficiently captured more cancer cells. Moreover, it could effectively reduce the paper background fluorescence. Due to the specific recognition of Con A with mannose and the effective signal amplification of mHCR, the proposed strategy exhibited excellent high sensitivity for the cytosensing of MCF-7 cells ranging from 100 to 1.0×10(7) and 80-5.0×10(7) cellsmL(-1) with the detection limit of 33 and 26 cellsmL(-1) for colorimetric and fluorescence, respectively. More importantly, this strategy was successfully applied to dynamically monitor cell-surface multi-glycans expression on living cells under external stimuli of inhibitors as well as for N-glycan expression inhibitor screening. These results implied that this biosensor has potential in studying complex native glycan-related biological processes and elucidating the N-glycan-related diseases in biological and physiological processes.

Tumor cell specific and lysosome-targeted delivery of nitric oxide for enhanced photodynamic therapy triggered by 808 nm near-infrared light

A novel cancer cell lysosome-targetable multifunctional NO-delivery nanoplatform (Lyso-Ru-NO@FA@C-TiO₂) (1) was developed.

A multifunctional nanoplatform for lysosome targeted delivery of nitric oxide and photothermal therapy under 808 nm near-infrared light

NIR light induced spatiotemporal delivery of NO to lysosome accompanied by hyperthermia was realized.

Recent advances in the synthesis and application of photocatalytic metal–metal oxide core–shell nanoparticles for environmental remediation and their recycling process

Metal–metal oxide core–shell nanoparticles have received enormous research attention owing to their fascinating physicochemical properties and extensive applications. In this review we have discussed the challenges and recent advances in their synthesis and application.

ZnO quantum dots decorated on optimized carbon nanotube intramolecular junctions exhibit superior field emission properties

Sensitive optical and superior field emission properties can be attained through the use of ZnO selective quantum well heterostructures grown on carbon nanotubes to fabricate carbon-zinc-oxide (CZO) nanotubes.

Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method

Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor-Ag2S (0.9 eV) quantum dots (QDs)-in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs fabricated by uniformly depositing the QDs into the TNTs via the successive ionic layer adsorption and reaction (SILAR) method were synthesized, respectively. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) results demonstrated that the Ag2S/CdS/TNTs prepared by SSM and other films were successfully prepared. In comparison with the four films of TNTs, CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs by SILAR, the Ag2S/CdS/TNTs prepared by SSM showed much better absorption capability and the highest photocurrent density in UV-vis range (320~800 nm). The cycles of local deposition have great influence on their photoelectric properties. The photocurrent density of Ag2S/CdS/TNTs by SSM with optimum deposition cycles of 6 was about 37 times that of TNTs without modification, demonstrating their great prospective applications in solar energy utilization fields.

Light-Tunable Generation of Singlet Oxygen and Nitric Oxide with a Bichromophoric Molecular Hybrid: a Bimodal Approach to Killing Cancer Cells

The design, synthesis, photochemical properties, and biological evaluation of a novel photoactivatable bichromophoric conjugate are reported. The compound 1, [4-(4,4-difluoro-2,6-diiodo-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacen-8-yl)-N-(3-((4-nitro-3-(trifluoromethyl)phenyl)amino)propyl)butanamide] combines a 2,6-diiodo-1,3,5,7-tetramethyl BODIPY derivative as singlet oxygen ((1) O2 ) photosensitizer and 4-nitro-3-(trifluoromethyl)aniline (NOPD) as nitric oxide (NO) photodonor, joined by an alkyl spacer. These two chromogenic units absorb in distinct regions of the visible spectrum, and their individual photochemical properties are conserved in the molecular conjugate. Irradiation of the bichromophoric conjugate with green light afforded (1) O2 in high quantum yields, whereas (1) O2 production was negligible with the use of blue light; under this latter condition, NO was released. Photogeneration of NO and cytotoxic (1) O2 can therefore be regulated by appropriately tuning the excitation light wavelength and intensity. Tested on melanoma cancer cells, this resulted in amplified photomortality relative to that of a structurally correlated model compound 2 [4-(4,4-difluoro-2,6-diiodo-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacen-8-yl)-N-(3-(p-tolylamino)propyl)butanamide] deprived of the NO-release capacity. The cellular uptake of 1, evaluated by confocal fluorescence microscopy, showed that the product is localized in the cytoplasm.

Simultaneous Point-of-Care Detection of Enterovirus 71 and Coxsackievirus B3

Human enterovirus 71 (EV71) is one of the pathogens that causes hand, foot, and mouth disease (HFMD), which generally leads to neurological diseases and fatal complications among children. Since the early clinical symptoms from EV71 infection are very similar to those from Coxsackievirus B3 (CVB3) infection, a robust and sensitive detection method that can be used to distinguish EV71 and CVB3 is urgently needed for prompting medical treatment of related diseases. Herein, based on immunomagnetic nanobeads and fluorescent semiconductor CdSe quantum dots (QDs), a method for simultaneous point-of-care detection of EV71 and CVB3 is proposed. The synchronous detection of EV71 and CVB3 virions was achieved within 45 min with high specificity and repeatability. The limits of detection are 858 copies/500 μL for EV71 and 809 copies/500 μL for CVB3.This proposed method was further validated with 20 human throat swab samples obtained from EV71 or CVB3 positive cases, with results 93.3% consistent with those by the real-time PCR method, demonstrating the potential of this method for clinical quantification of EV71 and CVB3. The method may also facilitate the prevention and treatment of the diseases.

A smart all-in-one theranostic platform for CT imaging guided tumor microwave thermotherapy based on IL@ZrO2 nanoparticles

This paper develops a simple multifunctional theranostic platform using an IL@ZrO₂ nanostructure for CT imaging guided tumor microwave thermotherapy.

This study develops a simple hollow ZrO₂ nanostructure as a carrier to encapsulate ionic liquid (IL), which integrates the CT imaging function of the ZrO₂ shell and the microwave susceptibility function of the IL core. The simple nanostructure can be used as a multifunctional theranostic agent via combining diagnostic and therapeutic modalities into one “package”. Based on the microwave susceptibility properties, the tumor inhibiting ratio can be over 90% in mice models after one-time thermal therapy upon microwave irradiation. In vitro and in vivo imaging results prove the potential of CT imaging application for real-time monitoring of biodistribution and metabolic processes, and assessing therapeutic outcomes. To our best knowledge, our study is the first example to achieve CT imaging and microwave thermal therapy simultaneously through a simple nanostructure. We anticipate that the simple IL@ZrO₂ nanostructure may build a useful platform for the clinical imaging guided therapy of tumors.

Fabrication of TiO2/MS (M = Pb, Zn) core–shell coaxial nanotube arrays and their photocatalytic properties

TiO₂/MS (M = Pb, Zn) core–shell coaxial nanotube arrays were prepared by a simple method of liquid deposition, where the template worked as a septum.

Photo-controlled targeted intracellular delivery of both nitric oxide and singlet oxygen using a fluorescence-trackable ruthenium nitrosyl functional nanoplatform

A multifunctional nitric oxide (NO) delivery nanoplatform that combines functionalities of target directing, fluorescence tracking, and photo-controlled target attacking was developed.

Simultaneous determination of concanavalin A and peanut agglutinin by dual-color quantum dots

In this work, we designed a novel detection strategy to realize simultaneous determination of multiplex lectin by labeling glucosamine (G1) and galactosamine (G2) with different-colored semiconductor quantum dots (QDs). On the basis of the agglutination of the aminosugar-labeled QDs induced by the exclusive binding between the lectin and sugar on the QDs surfaces, the fluorescence emission of the QDs supernatant after centrifugation decreased with relevant lectin concentration [i.e., when concanavalin A (Con A) exists alone], only green color fluorescence emission from QDs-G1 supernatant decreased, so it is peanut agglutinin (PNA) and red color fluorescence emission from QDs-G2. Moreover, since QDs can be simultaneously excited with multiple fluorescence colors and have a larger Stokes shift than organic fluorophores, when both Con A and PNA are present in the sample, both of the green and red color fluorescence emission from QDs-G1 and QDs-G2 supernatant would decrease, thus realizing the simultaneous determination of Con A and PNA. The detection limits of Con A and PNA are 0.30 and 0.18 nM (3σ), respectively. Furthermore, the present detection method not only can determine the protein/lectins by fluorescence spectral method but also can realize visualization detection by UV lamp illumination. To the best of our knowledge, this is the first report of such analytical method in multiple and simultaneous lectin detection.

Optical and thermal response of single-walled carbon nanotube-copper sulfide nanoparticle hybrid nanomaterials

This paper reports the optical and thermal response of a single-walled carbon nanotube-copper sulfide nanoparticle (SWNT-CuS NP) hybrid nanomaterial and its application as a thermoelectric generator. The hybrid nanomaterial was synthesized using oleylamine molecules as the linker molecules between SWNTs and CuS NPs. Measurements found that the hybrid nanomaterial has significantly increased light absorption (up to 80%) compared to the pure SWNT. Measurements also found that the hybrid nanomaterial thin-film devices exhibit a clear optical and thermal switching effect, which can be further enhanced up to 10 ×  by asymmetric illumination of light and thermal radiation on the thin-film devices instead of symmetric illumination. A simple prototype thermoelectric generator enabled by the hybrid nanomaterials is demonstrated, indicating a new route for achieving thermoelectricity.

Hierarchically plasmonic photocatalysts of Ag/AgCl nanocrystals coupled with single-crystalline WO₃ nanoplates

The hierarchical photocatalysts of Ag/AgCl@plate-WO₃ have been synthesized by anchoring Ag/AgCl nanocrystals on the surfaces of single-crystalline WO₃ nanoplates that were obtained via an intercalation and topochemical approach. The heterogeneous precipitation process of the PVP-Ag⁺-WO₃ suspensions with a Cl⁻ solution added drop-wise was developed to synthesize AgCl@WO₃ composites, which were then photoreduced to form Ag/AgCl@WO₃ nanostructures in situ. WO₃ nanocrystals with various shapes (i.e., nanoplates, nanorods, and nanoparticles) were used as the substrates to synthesize Ag/AgCl@WO₃ photocatalysts, and the effects of the WO₃ contents and photoreduction times on their visible-light-driven photocatalytic performance were investigated. The techniques of TEM, SEM, XPS, EDS, XRD, N₂ adsorption-desorption and UV-vis DR spectra were used to characterize the compositions, phases and microstructures of the samples. The RhB aqueous solutions were used as the model system to estimate the photocatalytic performance of the as-obtained Ag/AgCl@WO₃ nanostructures under visible light (λ ≥ 420 nm) and sunlight. The results indicated that the hierarchical Ag/AgCl@plate-WO₃ photocatalyst has a higher photodegradation rate than Ag/AgCl, AgCl, AgCl@WO₃ and TiO₂ (P25). The contents and morphologies of the WO₃ substrates in the Ag/AgCl@plate-WO₃ photocatalysts have important effects on their photocatalytic performance. The related mechanisms for the enhancement in visible-light-driven photodegradation of RhB molecules were analyzed.

Highly efficient visible light photocatalysis of novel CuS/ZnO heterostructure nanowire arrays

Here, a facile approach for the fabrication of CuS nanoparticle (NP)/ZnO nanowire (NW) heterostructures on a mesh substrate through a simple two-step solution method is demonstrated. Successive ionic layer adsorption and reaction (SILAR) was employed to uniformly deposit CuS NPs on the hydrothermally grown ZnO NW array. The synthesized CuS/ZnO heterostructure NWs exhibited superior photocatalytic activity under visible light compared to bare ZnO NWs. This strong photocatalytic activity under visible light is due to the interfacial charge transfer (IFCT) from the valence band of the ZnO NW to the CuS NP, which reduces CuS to Cu(2)S. After repeated cycles of photodecolorization of Acid Orange 7 (AO7), the photocatalytic behavior of CuS/ZnO heterostructure NWs exhibited no significant loss of activity. Furthermore, our CuS/ZnO NWs/mesh photocatalyst floats in solution via partial superhydrophobic modification of the NWs.

Upconversion nanomaterials: synthesis, mechanism, and applications in sensing

Upconversion is an optical process that involves the conversion of lower-energy photons into higher-energy photons. It has been extensively studied since mid-1960s and widely applied in optical devices. Over the past decade, high-quality rare earth-doped upconversion nanoparticles have been successfully synthesized with the rapid development of nanotechnology and are becoming more prominent in biological sciences. The synthesis methods are usually phase-based processes, such as thermal decomposition, hydrothermal reaction, and ionic liquids-based synthesis. The main difference between upconversion nanoparticles and other nanomaterials is that they can emit visible light under near infrared irradiation. The near infrared irradiation leads to low autofluorescence, less scattering and absorption, and deep penetration in biological samples. In this review, the synthesis of upconversion nanoparticles and the mechanisms of upconversion process will be discussed, followed by their applications in different areas, especially in the biological field for biosensing.