Different Types Of Metal Ions Research Articles

Anthocyanin‐Enhanced Bacterial Cellulose Nanofibers for Sustainable Hg(II) Ion Sensing

AbstractHg(II), poses a significant threat to both the environment and overall well‐being. The present indicator utilizes anthocyanin extract from roselle (Hibiscus sabdariffa), RSE, and incorporates it into bacterial cellulose nanofibers (BCNF) to detect Hg(II) ions. Through examination of the CIE Lab color variables, it is determined that the binding of Hg(II) leads to a discernible alteration in the color. The visible color changes as the Hg(II) concentration increases. ATR‐FTIR(Attenuated Total Reflectance‐Fourier transform infrared spectroscopy) and SEM(scanning electron microscopy) are utilized to analyze the bacterial cellulose nanofibers containing anthocyanin. The selectivity of the proposed sensor is assessed by conducting experiments with different types of metal ions including Co2+, Al3+, Na+, Ba2+, Ni2+, Mg2+, Cd2+, Pb2+, Fe2+, Fe3+, and Cu2+. The outcomes indicate that the sensor exhibits a remarkable ability to distinguish and respond specifically to Hg(II) ions. This particular sensing technique allows for the precise and reliable detection of Hg(II), with a detection limit of 0.72 ppm, by simply observing with the naked eye. For the effective treatment of a tap water sample, the BCNF‐RSE film provides successful results in the detection of Hg(II) ions. This innovative metallochromic sensor offers a promising solution for the on‐site, cost‐effective, portable, easy to use, and real‐time detection of Hg(II) ions.

Formation of rice protein fibrils is highly sensitive to the different types of metal ions: Aggregation behavior and possible mechanisms

The effects of Ca2+, Cu2+, and Fe3+ on rice protein (RP) fibril formation were investigated in this study. Low Ca2+ concentration (≤150 mM) moderately unfolded the conformation of RP, promoting the exposure of hydrophobic sites and RP fibril assembly. Fibril formation was especially promoted with earlier addition of Ca2+. Cu2+ and Fe3+ inhibited RP fibril formation in a dose-dependent manner, and the inhibitory effect of Fe3+ was stronger due to higher affinity with RP. Additionally, the addition of Cu2+ and Fe3+ reduced α-helix and β-sheet contents of RP, respectively, hindering the formation of stacked β-sheet, the main internal structure of fibrils. These two ions also resulted in the formation of random aggregates within 15–50 nm, which further inhibited the conversion of proteins to fibrils. Moreover, Cu2+ and Fe3+ prevented the recruitment of nucleus into fibril-growth-sites, and formed fibrils were disrupted into fragments when these ions were added.

A Review on Multiple I-III-VI Quantum Dots: Preparation and Enhanced Luminescence Properties.

I-III-VI type QDs have unique optoelectronic properties such as low toxicity, tunable bandgaps, large Stokes shifts and a long photoluminescence lifetime, and their emission range can be continuously tuned in the visible to near-infrared light region by changing their chemical composition. Moreover, they can avoid the use of heavy metal elements such as Cd, Hg and Pb and highly toxic anions, i.e., Se, Te, P and As. These advantages make them promising candidates to replace traditional binary QDs in applications such as light-emitting diodes, solar cells, photodetectors, bioimaging fields, etc. Compared with binary QDs, multiple QDs contain many different types of metal ions. Therefore, the problem of different reaction rates between the metal ions arises, causing more defects inside the crystal and poor fluorescence properties of QDs, which can be effectively improved by doping metal ions (Zn2+, Mn2+ and Cu+) or surface coating. In this review, the luminous mechanism of I-III-VI type QDs based on their structure and composition is introduced. Meanwhile, we focus on the various synthesis methods and improvement strategies like metal ion doping and surface coating from recent years. The primary applications in the field of optoelectronics are also summarized. Finally, a perspective on the challenges and future perspectives of I-III-VI type QDs is proposed as well.

Metal-Phenolic Network-Functionalized Magnetic Nanoparticles for Enzyme Immobilization.

Metal-phenolic network (MPN) coating is an emerging class of surface functionalization method and has attracted ever-growing interest in areas of bioengineering and biotechnology. Although various applications for MPN coatings, including drug delivery, cytoprotection, and antimicrobial surfaces, have been studied in the form of films and capsules, their interaction with enzyme molecules and the subsequent influence of biocatalytic properties are poorly understood. Herein, MPN coatings composed of different types of metal ions (CuII, FeIII, ZnII, MnII, AuIV) coordinated with tannic acid (TA) were fabricated on Fe3O4 nanoparticles as a facile nanoplatform for immobilizing alcohol dehydrogenase (ADH). The results show that the different polarization capacities of metal ions (i.e., Lewis acids) could affect the hydrophilicity and hydrophobicity of the coordinated MPN coatings, while the enzyme immobilization rate, biocatalytic activity, and stability are in turn influenced by the surface properties of the MPN coatings. Among the different metal ions, the Fe3O4-TA-ZnII showed the highest enzyme immobilizing efficiency (91.53%) and catalytic activity (60.45 U/mg ADH). Besides, the enzyme re-usability and tolerance to extreme conditions were both enhanced after immobilization. These results highlight an advanced strategy for the interfacial construction of hybrid heterogeneous biocatalytic systems with potential use in biomedical applications.

Stable Bimetallic Metal–Organic Framework with Dual-Functional Pyrazolate-Carboxylate Ligand: Rational Construction and C2H2/CO2 Separation

With the guidance of the hard/soft acid/base principle, we adopt a strategy to construct a novel robust metal–organic framework (MOF) by using a dual-functional ligand to coordinate with different types of metal ions in a one-pot reaction through coordination self-selection. A bimetallic MOF, namely BUT-85 (BUT = Beijing University of Technology), has been successfully synthesized with a rationally designed pyrazolate-carboxylate ligand. Its robust [Ni2(OH)(H2O)2Pz3]n chain (Pz = pyrazolate) with bridging OH–/H2O and pyrazolate groups is reported for the first time. This material shows good chemical stability in water and aqueous solutions with a pH range from 3 to 13. In addition, BUT-85 exhibits preferential adsorption behavior of C2H2 over CO2. It is proposed to be attributed to the abundant exposed bridging OH–/H2O sites in [Ni2(OH)(H2O)2Pz3]n chains, which is supported by the results of molecular simulations. Column breakthrough experiments further confirm that this MOF can realize efficient C2H2/CO2 separation. This strategy can not only enrich the structural library of MOFs but also optimize their properties and functions for promoting applications.

Synthesis of a hydrophobic association polymer with an inner salt structure for fracture fluid with ultra-high-salinity water

This study used a compound initiation free radical polymerization process to synthesize a hydrophobic association polymer (PDMA1) with good salt resistance for use in ultra-high salinity reservoirs. The critical association and entanglement concentrations of PDMA1 in deionized (DI) water were 1596 and 2799 mg/L, respectively. The properties of the polymer in simulated formation (SF) water were investigated using viscosity change and conductivity tests, and the apparent viscosity of the PDMA1 solution was investigated using apparent viscosity, viscoelasticity, and thixotropy experiments. To a certain extent, the apparent viscosity of the solution was found to be influenced by metal ions. Under total dissolved solids (TDS) concentrations of up to 239,500 ppm, when the polymer concentration exceeded the critical entanglement concentration, the apparent viscosity of the polymer remained close to that of DI water. Additionally, the viscosity of the PDMA1 solution was affected by different types of metal ions, and the polymer solution thickened owing to divalent cations. PDMA1 is resistant to salt owing to hydrophobic interaction, electrostatic shielding, and double-layer compression. The results of the thixotropy and viscoelasticity tests revealed the thixotropy loop area of the PDMA1 solution in SF water to be greater than that in DI water. Under these conditions, PDMA1 is mostly viscous at low shear frequencies and mostly elastic at high shear frequencies. The PDMA1 inner-salt hydrophobic association polymer can be utilized as a chemical agent for tertiary recovery and fracturing, processes in high-salinity reservoirs, particularly for aggravating fracturing fluid.

The study of the molecular mechanism of Lactobacillus paracasei clumping via divalent metal ions by electrophoretic separation

In this work, the molecular mechanism of Lactobacillus paracasei bio-colloid clumping under divalent metal ions treatment such as zinc, copper and magnesium at constant concentrations was studied. The work involved experimental (electrophoretic - capillary electrophoresis in pseudo-isotachophoresis mode, spectroscopic and spectrometric - FT-IR and MALDI-TOF-MS, microscopic - fluorescent microscopy, and flow cytometry) and theoretical (DFT calculations of model complex systems) characterization. Electrophoretic results have pointed out the formation of aggregates under the Zn2+ and Cu2+ modification, whereas the use of the Mg2+ allowed focusing the zone of L. paracasei biocolloid. According to the FT-IR analysis, the major functional groups involved in the aggregation are deprotonated carboxyl and amide groups derived from the bacterial surface structure. Nature of the divalent metal ions was shown to be one of the key factors influencing the bacterial aggregation process. Proteomic analysis showed that surface modification had a considerable impact on bacteria molecular profiles and protein expression, mainly linked to the activation of carbohydrate and nucleotides metabolism as well with the transcription regulation and membrane transport. Density-functional theory (DFT) calculations of modeled Cu2+, Mg2+ and Zn2+ coordination complexes support the interaction between the divalent metal ions and bacterial proteins. Consequently, the possible mechanism of the aggregation phenomenon was proposed. Therefore, this comprehensive study could be further applied in evaluation of biocolloid aggregation under different types of metal ions.

Octanuclear Ni4 Ln4 Coordination Aggregates from Schiff Base Anion Supports and Connecting of Two Ni2 Ln2 Cubes: Syntheses, Structures, and Magnetic Properties.

A family of 3d-4f aggregates have been reported through guiding the dual coordination modes of ligand anion (HL- ) and in situ generated ancillary bridge driven self-assembly coordination responses toward two different types of metal ions. Reactions of lanthanide(III) nitrate (Ln=Gd, Tb, Dy, Ho and Yb), nickel(II) acetate and phenol-based ditopic ligand anion of 2-[{(2-hydroxypropyl)imino}methyl]-6-methoxyphenol (H2 L) in MeCN-MeOH (3 : 1) mixture and LiOH provided five new octanuclear Ni-4f coordination aggregates from two Ni2 Ln2 cubanes. Single-crystal X-ray diffraction analysis reveals that all the members of the family are isostructural, with the central core formed from the coupling of two distorted [Ni2 Ln2 O4 ] heterometallic cubanes [Ni2 Ln2 (HL)2 (μ3 -OH)2 (OH)(OAc)4 ]+ (Ln=Gd (1), Tb (2), Dy (3), Ho (4) and Yb (5)). Higher coordination demand of 4f ions induced the coupling of the two cubes by (OH)(OAc)2 bridges. Variable temperature magnetic study reveals weak coupling between the Ni2+ and Ln3+ ions. For the Tb (2) and Dy (3) analogs, the compounds are SMMs without an applied dc field, whereas the Gd (1) analogue is not an SMM. The observation revealed thus that the anisotropy of the Ln3+ ions is central to display the SMM behavior within this structurally intriguing family of compounds.

Two-dimensional positive or negative patterning of submicrometer silica spheres on polyimide via ion implantation and selective adsorption

In this paper, we report a large-area 2D patterning technique via ion implantation and selective adsorption. It is found that the surface zeta potential (ξ) of polyimide (PI) can be changed by implanting different types of metal ions. On the surface of the Cu or Ni ion patterned implanted polyimide, both negative and positive adsorption patterns of submicrometer silica particles can be realized. The formation of different patterns is mainly decided by the surface zeta potential contrast ratio between implanted part and the unimplanted part of PI and the zeta potential of particles. Moreover, the shape of the patterns can be regulated by changing the liquid surface tension.

Organic-inorganic backbone with high contents of proton conducting groups: A newly designed high performance proton conductor

To prepare new high temperature organic-inorganic proton conductor for applications in proton exchange membrane fuel cells (PEMFC), 2,4,6-triphosphono-1,3,5-triazine (TPT) was synthesized and reacted with three different types of metal ions (Ce, Zr and Fe) in varied molar ratios. In each TPT molecule, three phosphonic acid groups were introduced into the triazine ring to obtain an organic compound with high content of proton conducting groups, which was then reacted with metal ions to ensure the insolubility in water aiming to avoid leaking during PEMFC operation. CeTPT(1:2) exhibited good thermal stability up to 200 °C and showed crystalline phase. MTPT exhibited high ion exchange capacity (IEC, 1.53–2.12 meq. g−1). CeTPT(1:2) exhibited highest proton conductivity among all samples, which reached 0.116, 0.070 and 0.034 S cm−1 at 100% relative humidity (RH), 50% RH and anhydrous conditions at 180 °C, respectively. The corresponding activation energy for proton conduction was 14.5, 16.0 and 21.5 kJ mol−1 at 100% RH, 50% RH and anhydrous conditions, respectively. The mechanism for proton conduction was proposed according to the activation energy. The proton conductor can find promising applications in fuel cells, corrosion inhibition and water desalination due to its good thermal stability and high IEC.

Constructing an E-Nose Using Metal-Ion-Induced Assembly of Graphene Oxide for Diagnosis of Lung Cancer via Exhaled Breath.

A flexible electronic-nose (E-nose) was constructed by assembling graphene oxide (GO) using different types of metal ions (Mx+) with different ratio of GO to Mx+. Owing to the cross-linked networks, the Mx+-induced assembly of graphene films resulted in different porous structures. A chemi-resistive sensor array was constructed by coating the GO-M hybrid films on PET substrate patterned with 8 interdigited electrodes, followed by in situ reduction of GO to rGO with hydrazine vapor. Each of the sensing elements on the sensor array showed a cross-reactive response toward different types of gases at room temperature. Compared to bare rGO, incorporation of metal species into rGO significantly improved sensitivity owing to the additional interaction between metal species and gas analyte. Principle component analysis (PCA) showed that four types of exhaled breath (EB) biomarkers including acetone, isoprene, ammonia, and hydrothion in sub-ppm concentrations can be discriminated well. To overcome the interference from humidity in EB, a protocol to collect and analyze EB gases was established and further validated by simulated EB samples. Finally, clinical EB samples collected from patients with lung cancer and healthy controls were analyzed. In a 106 case study, the healthy group can be accurately distinguished from lung cancer patients by linear discrimination analysis. With the assistance of an artificial neural network, a sensitivity of 95.8% and specificity of 96.0% can be achieved in the diagnosis of lung cancer based on the E-nose. We also find that patients with renal failure can be distinguished through comparison of dynamic response curves between patient and healthy samples on some specific sensing elements. These results demonstrate the proposed E-nose will have great potential in noninvasive disease screening and personalized healthcare management.

DNAzymes as Activity-Based Sensors for Metal Ions: Recent Applications, Demonstrated Advantages, Current Challenges, and Future Directions.

Metal ions can be beneficial or toxic depending on their identity, oxidation state, and concentration. Therefore, the ability to detect and quantify different types of metal ions using portable sensors or in situ imaging agents is important for better environmental monitoring, in vitro medical diagnostics, and imaging of biological systems. While numerous metal ions in different oxidation states are present in the environment and biological systems, only a limited number of them can be detected effectively using current methods. In this Account, we summarize research results from our group that overcome this limitation by the development of a novel class of activity-based sensors based on metal-dependent DNAzymes, which are DNA molecules with enzymatic activity. First, we have developed an in vitro selection method to obtain DNAzymes from a large DNA library of up to 1015 sequences that can carry out cleavage of an oligonucleotide substrate only in the presence of a specific metal ion with high selectivity. Negative selection steps can further be used to improve the selectivity against potentially competing targets by removing sequences that recognize the competing metal ions. Second, we have developed a patented catalytic beacon method to transform the metal-dependent DNAzyme cleavage reaction into a turn-on fluorescent signal by attaching a fluorophore and quenchers to the DNAzyme complex. Because of the difference in the melting temperatures of DNA hybridization before and after metal-ion-dependent cleavage of the DNAzyme substrate, the fluorophore on the DNA cleavage product can be released from its quenchers to create a turn-on fluorescent signal. Because DNAzymes are easy to conjugate with other signaling moieties, such as gold nanoparticles, lanthanide-doped upconversion nanoparticles, electrochemical agents, and gadolinium complexes, these DNAzymes can also readily be converted into colorimetric sensors, upconversion luminescence sensors, electrochemical sensors, or magnetic resonance contrast agents. In addition to describing recent progress in developing and applying these metal ion sensors for environmental monitoring, point-of-care diagnostics, cellular imaging, and in vivo imaging in zebrafish, we summarize major advantages of this class of activity-based sensors. In addition to advantages common to most activity-based sensors, such as enzymatic turnovers that allow for signal amplification and the use of initial rates instead of absolute signals for quantification to avoid interferences from sample matrices, the DNAzyme-based sensors allow for in vitro selection to expand the method to almost any metal ion under a variety of conditions, negative selection to improve the selectivity against competing targets, and reselection of DNAzymes and combination of active and inactive variants to fine-tune the dynamic range of detection. The use of melting temperature differences to separate target binding from signaling moieties in the catalytic beacon method allows the use of different fluorophores and nanomaterials to extend the versatility and modularity of this sensing platform. Furthermore, sensing and imaging artifacts can be minimized by using an inactive mutant DNAzyme as a negative control, while spatiotemporal control of sensing/imaging can be achieved using optical, photothermal, and endogenous orthogonal caging methods. Finally, current challenges, opportunities, and future perspectives for DNAzymes as activity-based sensors are also discussed.

Changes in physico-chemical properties, microstructures, molecular forces and gastric digestive properties of preserved egg white during pickling with the regulation of different metal compounds

In this paper, the effects of three different metal compounds, including lead oxide, copper sulfate, mixed compound of zinc sulfate and copper sulfate, on the physico-chemical properties, microstructures, molecular forces and digestion characteristics of preserved egg white were studied. The results showed that different types of metal ions had significant different effects on the penetration rate of alkali into the egg, the moisture content and the viscosity of the preserved egg white. The content of moisture and alkali in the preserved egg white pickled by copper sulfate were the largest among the three treatment groups, and the viscosity change of egg white was the slowest. L* value, a* value and b* value of preserved eggs pickled by copper method were all the largest. The eggs pickled by lead oxide possessed the optimal texture and moderate hardness and good elasticity. The eggs pickled by the mixture of copper sulfate and zinc sulfate possessed the smallest egg white gel mesh and the most compact structure, and the gel hardness was relatively high. The content of disulfide bond in preserved egg white gel pickled by lead oxide was the highest. Although there were no differences among the preserved egg whites pickled with three metal compounds on gastric digestibility, there were different at the different pickling stages. The results showed that different types of metal salts added during pickling could affect the density of the internal structure of preserved egg white gel and the molecular forces, thus changing the physico-chemical and digestive properties of the gel.

Strategically Designed Zeolitic Imidazolate Frameworks for Controlling the Degree of Graphitization

Abstract The zeolitic imidazolate frameworks (ZIFs) ZIF-8 and ZIF-67 are well-known as belonging to the series of metal-organic frameworks. Using different types of metal ions in them, such as Zn2+ and Co2+ simultaneously, brings both advantages and disadvantages with respect to the carbonization process. For tailoring their properties, we suggest that the best approach involves control of the bimetallic ZIF-derived carbon nanoarchitecture, which is hybridized through the synergistic effects of each metal ion. In this study, the bimetallic ZIFs were designed by controlling the molar ratio of zinc (Zn2+) and cobalt (Co2+) ions, and the carbon nanoarchitecture was subsequently formed by a facile heat treatment and acid leaching. We demonstrate this approach to achieve tailored ZIF derived carbon nanoarchitectures with different pore sizes, surface areas, and degree of graphitization. These pave the way to finding the optimal carbon nanoarchitecture for specific applications such as Li-O2 air cell.

Bimetallic Ions Codoped Nanocrystals: Doping Mechanism, Defect Formation, and Associated Structural Transition.

Ionic codoping offers a powerful approach for modifying material properties by extending the selection of potential dopant ions. However, it has been a major challenge to introduce certain ions that have hitherto proved difficult to use as dopants (called "difficult-dopants") into crystal structures at high concentrations, especially through wet chemical synthesis. Furthermore, the lack of a fundamental understanding of how codopants are incorporated into host materials, which types of defect structures they form in the equilibrium state, and what roles they play in material performance, has seriously hindered the rational design and development of promising codoped materials. Here we take In3+ (difficult-dopants) and Nb5+ (easy-dopants) codoped anatase TiO2 nanocrystals as an example and investigate the doping mechanism of these two different types of metal ions, the defect formation, and their associated impacts on high-pressure induced structural transition behaviors. It is experimentally demonstrated that the dual mechanisms of nucleation and diffusion doping are responsible for the synergic incorporation of these two dopants and theoretically evidenced that the defect structures created by the introduced In3+, Nb5+ codopants, their resultant Ti3+, and oxygen vacancies are locally composed of both defect clusters and equivalent defect pairs. These formed local defect structures then act as nucleation centers of baddeleyite- and α-PbO2-like metastable polymorphic phases and induce the abnormal trans-regime structural transition of codoped anatase TiO2 nanocrystals under high pressure. This work thus suggests an effective strategy to design and synthesize codoped nanocrystals with highly concentrated difficult-dopants. It also unveils the significance of local defect structures on material properties.

A novel, highly sensitive, selective, reversible and turn-on chemi-sensor based on Schiff base for rapid detection of Cu(II)

In this work, a novel optical fluoro-chemisensor was designed and synthesized for copper (II) ions detection. The sensor film is created by embedded N,N-Bis(2-hydroxo-5-bromobenzyl)ethylenediamine in poly vinyl chloride (PVC) film in presence of dioctyl phthalate (DOP) as plasticizer. The receptor Schiff base reveals “off-on” mode with high selectivity, significant sensitivity to Cu(II) ions. The selectivity of optical sensor for Cu(II) ions is the result of chelation enhanced fluorescence (CHEF). The optimal conditions of pH and response time at which higher efficiency of sensor film is performed was found to be 6.8 and 2.48min. The possible interference of other metal ions in solution was examined in presence of different types of metal ions. This film shows high selectivity and ultra-sensitivity with low detection limit LOD (1.1×10−8M). Thus, these considerable properties make it viable to monitor copper metal ions within very low concentration range (0–15×10−6M Cu(II)) and highly selective even in the presence of different types of metal ions. The sensor reversibility was achieved by utilizing EDTA solution with concentration of 0.1M solution.

Selectable Ultrasensitive Detection of Hg(2+) with Rhodamine 6G-Modified Nanoporous Gold Optical Sensor.

An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg2+-Au+ interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity. The optical sensor has a detection sensitivity down to 0.6 pM for Hg2+ and CH3Hg+ ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles. Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications.

Study on the fluorescent chemosensors based on a series of bis-Schiff bases for the detection of zinc(II)

In order to study the influence of different substituent groups on the fluorescence properties, a series of bis-Schiff bases (L) with electron-donating groups (salicylaldehyde, o-vanillin, 2,4-dihydroxybenzaldehyde) and electron-drawing group (4-formylbenzoic acid) have been synthesized, and characterized by IR spectrum, NMR, mass spectrum, and fluorescence spectroscopy. The investigation of the fluorescent properties reveals that the fluorescence can be enhanced when the bis-Schiff base ligands with electron-donating groups complex with Zn ion, while other kinds of metal complexes with these ligands do not show any enhancement, whereas no fluorescence enhancement can be observed when the ligand with electron-drawing group complexes with all different types of metal ions. In addition, as for the ligands with electron-donating groups detecting zinc ion, the fluorescence intensity is linear correlated with the concentration of zinc ion. Therefore, the study indicates that the ligands with electron-donating groups can be used as Zn ion fluorescent sensor.

Bottom-Up Synthesis of Metal-Ion-Doped WS₂ Nanoflakes for Cancer Theranostics.

Recently, two-dimensional transition metal dichalcogenides (TMDCs) have received tremendous attention in many fields including biomedicine. Herein, we develop a general method to dope different types of metal ions into WS2 nanoflakes, a typical class of TMDCs, and choose Gd(3+)-doped WS2 (WS2:Gd(3+)) with polyethylene glycol (PEG) modification as a multifunctional agent for imaging-guided combination cancer treatment. While WS2 with strong near-infrared (NIR) absorbance and X-ray attenuation ability enables contrasts in photoacoustic (PA) imaging and computed tomography (CT), Gd(3+) doping offers the nanostructure a paramagnetic property for magnetic resonance (MR) imaging. As revealed by trimodal PA/CT/MR imaging, WS2:Gd(3+)-PEG nanoflakes showed efficient tumor homing after intravenous injection. In vivo cancer treatment study further uncovered that WS2:Gd(3+)-PEG could not only convert NIR light into heat for photothermal therapy (PTT) but also enhance the ionizing irradiation-induced tumor damage to boost radiation therapy (RT). Owing to the improved tumor oxygenation after the mild PTT, the combination of PTT and RT induced by WS2:Gd(3+)-PEG resulted in a remarkable synergistic effect to destroy cancer. Our work highlights the promise of utilizing inherent physical properties of TMDC-based nanostructures, whose functions could be further enriched by elementary doping, for applications in multimodal bioimaging and synergistic cancer therapy.

Multicolor Emitting Block Copolymer-Integrated Graphene Quantum Dots for Colorimetric, Simultaneous Sensing of Temperature, pH, and Metal Ions

Highly selective optical sensors that are capable of detecting complex stimuli have attracted significant interest in environmental, biomedical, and analytical chemistry applications. In this Article, we report the development of novel and versatile platform for highly efficient, colorimetric multifunctional sensors using block copolymer-integrated graphene quantum dots (bcp-GQDs). In particular, the multisensing behavior is successfully generated simply by grafting blue-emitting, temperature-responsive block copolymers onto green-emitting, 10 nm size GQD that provides luminescent response to pH changes. Thus, the bcp-GQDs showed simultaneous, orthogonal sensing behavior to temperature and pH, as well as dose-dependent responses to different types of metal ions. In addition, the bcp-GQD sensor showed excellent reversibility and dispersion stability in pure water, indicating that our system is an ideal platform for environmental and biological applications. The detailed mechanism of the responsive behavior of the bcp-GQDs was elucidated by measurements of time-resolved fluorescence and dynamic light scattering.