Design of Multifunctional Fluorescent Hybrid Materials Based on SiO2 Materials and Core-Shell Fe3 O4 @SiO2 Nanoparticles for Metal Ion Sensing

CsPbBr3 perovskite quantum dots-based Janus membrane with multifunction of luminescence, magnetism and aeolotropic electroconductivity

Lead halide perovskite quantum dots (QDs) are promising semiconductors for next-generation photoelectric devices. However, the development of perovskite QDs-based multifunctional materials still needs to be addressed in order to further advance the application of perovskite QDs. Herein, a successful synthesis of Janus microfibers array Janus membrane (JMAJM) with up-down structure and multifunction of luminescence, magnetism and electroconductivity is firstly achieved based on CsPbBr3 QDs through a parallel electrospinning. JMAJM comprises up-down two layers tightly bonded together. The up-layer of JMAJM is luminescence/magnetism Janus microfibers array (L/M-JMAJM) constructed by [CsPbBr3/polymethyl methacrylate (PMMA)]//[CoFe2O4/PMMA] Janus microfibers as building elements. The down-layer of JMAJM is luminescence/electroconductivity Janus microfibers array (L/E-JMAJM) fabricated by [CsPbBr3/PMMA]//[polyaniline (PANI)/PMMA] Janus microfibers as building elements. Two independent microcosmic regions are designed and realized in a Janus microfiber, confining luminescence with magnetic or conductive substances into their respective regions, thus minimizing adverse effects of other dark-colored functional substances on the fluorescence of CsPbBr3 QDs. This peculiar Janus microfiber enables the effective separation and high integration of CsPbBr3 QDs with other functional substances. The up-down structure of JMAJM ensures a high integration of luminescence, magnetism and conductivity. Meanwhile, JMAJM addresses the environmental instability of CsPbBr3 QDs while simultaneously endows perovskite QDs-based materials with additional functions to realize multifunction. Under ultraviolet excitation, fluorescence characteristics of the CsPbBr3 QDs in JMAJM are maintained, exhibiting a vibrant green emission at 517 nm. Meanwhile, JMAJM achieves a maximum saturation magnetization of 20.32 emu·g-1, high conductance of 10-2 S and aeolotropic electroconductivity degree of 107. The combination of micro-partition with macro-partition in JMAJM receives superior concurrent luminescence-magnetic-conductive multifunction. This work provides a novel idea and strategy for advancing perovskite QDs-based multifunctional materials.

A nanoparticle-assisted signal-enhancement technique for lateral flow immunoassays

Lateral flow immunoassay (LFIA), an affordable and rapid paper-based detection technology, is employed extensively in clinical diagnosis, environmental monitoring, and food safety analysis. The COVID-19 pandemic underscored the validity and adoption of LFIA in performing large-scale clinical and public health testing. The unprecedented demand for prompt diagnostic responses and advances in nanotechnology have fueled the rise of next-generation LFIA technologies. The utilization of nanoparticles to amplify signals represents an innovative approach aimed at augmenting LFIA sensitivity. This review probes the nanoparticle-assisted amplification strategies in LFIA applications to secure low detection limits and expedited response rates. Emphasis is placed on comprehending the correlation between the physicochemical properties of nanoparticles and LFIA performance. Lastly, we shed light on the challenges and opportunities in this prolific field.

Fluorogen-Functionalized Mesoporous Silica Hybrid Sensing Materials: Applications in Cu2+ Detection

Since Cu2+ ions play a pivotal role in both ecosystems and human health, the development of a rapid and sensitive method for Cu2+ detection holds significant importance. Fluorescent mesoporous silica materials (FMSMs) have garnered considerable attention in the realm of chemical sensing, biosensing, and bioimaging due to their distinctive structure and easily functionalized surfaces. As a result, numerous Cu2+ sensors based on FMSMs have been devised and extensively applied in environmental and biological Cu2+ detection over the past few decades. This review centers on the recent advancements in the methodologies for preparing FMSMs, the mechanisms underlying sensing, and the applications of FMSMs-based sensors for Cu2+ detection. Lastly, we present and elucidate pertinent perspectives concerning FMSMs-based Cu2+ sensors.

Solid-state self-catalyzed growth of N-doped carbon tentacles on an M(Fe, Co)Se surface for rechargeable Zn-air batteries

A scalable and facile solid-catalyzed growth approach is reported to integrate N-doped carbon tentacles with metal selenide nanoparticles, showing great potential for mass production of non-precious metal catalysts for rechargeable Zn-air batteries.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

A Review on Organic Fluorimetric and Colorimetric Chemosensors for the Detection of Ag(I) Ions

Organic compounds display several electronic and structural features which enable their application in various fields, ranging from biological to non-biological. These compounds contain heteroatoms like sulfur, nitrogen and oxygen, which provide coordination sites to act as ligands in the field of coordination chemistry and are used as chemosensors to detect various metal ions. This review article covers different organic compounds including thiourea, Schiff base, pyridine, thiophene, coumarin, triazolyl pyrenes, imidazole, fluorescein, thiazole, tricarbocyanine, rhodanine, porphyrin, hydrazone, benzidine and other functional groups based chemosensors, that contain heteroatoms like sulfur, nitrogen and, oxygen for fluorimetric and colorimetric detection of Ag+ in different environmental, agricultural, and biological samples. Further, the sensing mechanism and performances of these chemosensors have been discussed, which could help the readers for the future design of highly efficient, selective, and sensitive chemosensors for the detection and determination of Ag+ ions.

Multifunctional Yolk-Shell Structured Magnetic Mesoporous Polydopamine/Carbon Microspheres for Photothermal Therapy and Heterogenous Catalysis

Yolk-shell structure with magnetic core, interior void and mesoporous polymer/carbon shell demonstrate potential applications in biocatalysis, magnetic biological separation, biomedicine, and magnetic resonance imaging due to their comprehensive benefits of magnetic and mesoporous shells. Herein, yolk-shell structured magnetic mesoporous polydopamine microspheres (Fe3O4@Void@mPDA) and the corresponding derivatives of carbon-based microspheres (Fe3O4@Void@mCN) are successfully fabricated through an interface assembly and selective etching approach. The obtained monodisperse Fe3O4@Void@mPDA microspheres consist of a magnetic core, a mesoporous polydopamine shell, and the large void formed between them, with perpendicular mesopores (5.2 nm), high surface area (303.3 m2g-1), and richness of functional groups. The Fe3O4@Void@mPDA microspheres show a remarkable inhibitory effect on tumor cells. Moreover, the Fe3O4@Void@mCN microspheres can immobilize ultrafine Au nanoparticles for hydrogenation of 4-nitrophenol with superb catalytic activity and excellent magnetic reusability.

Amphiphilic shell nanomagnetic adsorbents for selective and highly efficient capture of low-density lipoprotein from hyperlipidaemia serum

Removal of low-density lipoprotein (LDL) from hyperlipemia patients’ blood represents an effective approach to prevent the progression of atherosclerotic cardiovascular disease. Based on the LDL structural characteristics and intermolecular interactions,...

Preparation of Dual-Layered Core-Shell Fe3O4@SiO2 Nanoparticles and Their Properties of Plasmid DNA Purification

The rapid purification of biomaterials such as DNA, RNA, and antibodies has attracted extensive attention, and research interest has increased further with the COVID-19 pandemic. In particular, core–shell-structured superparamagnetic nanoparticles have been continuously studied for their application as biopurification materials. It has been reported that Fe₃O₄@SiO₂ nanoparticles are one of the most promising candidates for separating nucleic acids via a simple and rapid process. This study proposed a fabrication method for dual-layered Fe₃O₄@SiO₂ nanoparticles, in which the density of the SiO₂ shell was controlled using an intermediate surfactant during the SiO₂ coating. After the fabrication of dual-layered Fe₃O₄@SiO₂ nanoparticles, structural, morphological, and magnetic analyses were conducted. The results showed that the Fe₃O₄ nanoparticles were surrounded by a dense layer 15.6~27.9 nm thick and a porous layer 24.2~44.4 nm thick, and had superparamagnetic properties with high saturated magnetization at room temperature (86.9 emu/g). Then, the optimal conditions for the biopurification material were suggested based on analysis of the selective separation of plasmid DNA.

A visualized ratiometric fluorescence sensing system for copper ions based on gold nanoclusters/perovskite quantum dot@SiO2 nanocomposites

Excessive copper ions (Cu²⁺) cause serious environmental pollution and even endanger the health of organisms. Fluorescence chemosensing materials are widely used in the detection of metal ions due to their simple operation and high sensitivity. In this study, SiO₂-encapsulated single perovskite quantum dot (PQD@SiO₂) core-shell nanostructures which show strong, stable, and green fluorescence are synthesized and composited with gold nanoclusters (AuNCs) which show Cu²⁺-sensitive and red light-emitting fluorescence to obtain a visualized ratiometric fluorescence sensor (AuNCs/PQD@SiO₂) for the detection of Cu²⁺. In the visualized detection of Cu²⁺, the green fluorescence emitted from the ion-insensitive PQD@SiO₂ component is used as a reference signal and the red fluorescence emitted by ion-sensitive AuNC component is adopted as a sensing signal. In the presence of Cu²⁺, the red fluorescence is quenched whereas the green fluorescence remains stable, which results in a visualized fluorescence color change from orange-red to yellow and finally to green with increasing Cu²⁺ concentration. The significant change in the fluorescence color of AuNCs/PQD@SiO₂ in response to Cu²⁺ enables a rapid, sensitive, and visualized detection of Cu²⁺. Further accurate and sensitive ratiometric fluorescence analysis of Cu²⁺ can be accomplished by measuring the ratio of fluorescence intensities at 643 and 520 nm (I₆₄₃/I₅₂₀) at a certain Cu²⁺ level. The developed AuNCs/PQD@SiO₂-based sensor has been validated by its satisfactory application in the detection of Cu²⁺ in human serum and environmental water samples.

One-Step Biosynthesis of Soft Magnetic Bacterial Cellulose Spheres with Localized Nanoparticle Functionalization

Actuated structures are becoming relevant in medical fields; however, they call for flexible/soft-base materials that comply with biological tissues and can be synthesized in simple fabrication steps. In this work, we extend the palette of techniques to afford soft, actuable spherical structures taking advantage of the biosynthesis process of bacterial cellulose. Bacterial cellulose spheres (BCS) with localized magnetic nanoparticles (NPs) have been biosynthesized using two different one-pot processes: in agitation and on hydrophobic surface-supported static culture, achieving core-shell or hollow spheres, respectively. Magnetic actuability is conferred by superparamagnetic iron oxide NPs (SPIONs), and their location within the structure was finely tuned with high precision. The size, structure, flexibility and magnetic response of the spheres have been characterized. In addition, the versatility of the methodology allows us to produce actuated spherical structures adding other NPs (Au and Pt) in specific locations, creating Janus structures. The combination of Pt NPs and SPIONs provides moving composite structures driven both by a magnetic field and a H₂O₂ oxidation reaction. Janus Pt/SPIONs increased by five times the directionality and movement of these structures in comparison to the controls.

A multifunctional targeted nanoprobe with high NIR-II PAI/MRI performance for precise theranostics of orthotopic early-stage hepatocellular carcinoma

Early diagnosis and effective treatment of hepatocellular carcinoma (HCC) is quite critical for improving patients' prognosis. The combination of second near-infrared window photoacoustic imaging (NIR-II PAI) and T₂-magnetic resonance imaging (T₂-MRI) is promising for achieving omnibearing information on HCC diagnosis due to the complementary advantages of outstanding optical contrast, high temporospatial resolution and soft-tissue resolution. Thus, the rational design of a multifunctional targeted nanoplatform with outstanding performance in dual-modal NIR-II PAI/T₂-MRI is particularly valuable for precise diagnosis and imaging-guided non-invasive photothermal therapy (PTT) of early-stage HCC. Herein, a versatile targeted organic-inorganic hybrid nanoprobe was synthesized as a HCC-specific contrast agent for sensitive and efficient theranostics. The developed multifunctional targeted nanoprobe yielded superior HCC specificity, reliable stability and biocompatibility, high imaging contrast in both NIR-II PAI and T₂-MRI, and an excellent photothermal conversion efficiency (74.6%). Furthermore, the theranostic efficiency of the targeted nanoprobe was systematically investigated using the orthotopic early HCC-bearing mice model. The NIR-II PAI exhibited sensitive detection of ultra-small HCCs (diameter less than 1.8 mm) and long-term real-time monitoring of the tumor and nanoprobe targeting process in deep tissues. The T₂-MRI demonstrated clear imaging contrast and a spatial relationship between micro-HCC and adjacent structures for a comprehensive description of the tumor. Moreover, when using the targeted nanoprobe, the non-invasively targeted PTT of orthotopic early HCC was carried out under reliable dual-modal imaging guidance with remarkable anti-tumor efficiency and biosafety. This study provides an insight for constructing a multifunctional targeted nanoplatform for precise and comprehensive theranostics of early-stage HCC, which would greatly benefit the patients in the era of precision medicine.

Ag2CO3 containing magnetic nanocomposite as a powerful and recoverable catalyst for Knoevenagel condensation

In this paper, the synthesis, characterization and catalytic application of a novel magnetic silica-supported Ag2CO3 (MS/Ag2CO3) with core-shell structure are developed. The MS/Ag2CO3 nanocomposite was prepared through chemical modification of magnetic MS nanoparticles with AgNO3 under alkaline conditions. The structure, chemical composition and magnetic properties of MS/Ag2CO3 were investigated by using VSM, PXRD, FT-IR, EDX and SEM techniques. The MS/Ag2CO3 nanocomposite was used as an effective catalyst for the Knoevenagel condensation under solvent-free conditions at 60 °C in an ultrasonic bath. The recovery and leaching tests were performed to study the nature of the MS/Ag2CO3 catalyst under applied conditions.

Silica-Coated Fe3O4 Nanoparticles as a Bifunctional Agent for Magnetic Resonance Imaging and ZnII Fluorescent Sensing

Bifunctional magnetic/fluorescent core-shell silica nanospheres (MNPs) encapsulated with the magnetic Fe₃O₄ core and a derivate of 8-amimoquinoline (N-(quinolin-8-yl)-2-(3-(triethoxysilyl) propylamino) acetamide) (QTEPA) into the shell were synthesized. These functional MNPs were prepared with a modified stöber method and the formed Fe₃O₄@SiO₂-QTEPA core-shell nanocomposites are biocompatible, water-dispersible, and stable. These prepared nanoparticles were characterized by X-ray power diffraction (XRD), transmission electron microscopy (TEM), thermoelectric plasma Quad II inductively coupled plasma mass spectrometry (ICP-MS), superconducting quantum interference device (SQUID), TG/DTA thermal analyzer (TGA) and Fourier transform infrared spectroscopy (FTIR). Further application of the nanoparticles in detecting Zn²⁺ was confirmed by the fluorescence experiment: the nanosensor shows high selectivity and sensitivity to Zn²⁺ with a 22-fold fluorescence emission enhancement in the presence of 10 μM Zn²⁺. Moreover, the transverse relaxivity measurements show that the core-shell MNPs have T2 relaxivity (r2) of 155.05 mM^-1 S^-1 based on Fe concentration on the 3.0 T scanner, suggesting that the compound can be used as a negative contrast agent for MRI. Further in vivo experiments showed that these MNPs could be used as MRI contrast agent. Therefore, the new nanosensor provides the dual modality of magnetic resonance imaging and optical imaging.

Highly selective fluorescence detection of Cu2+ based on Schiff base functionalized periodic mesoporous organosilicas

A novel copper ion sensing periodic mesoporous organosilica (SCN-PMO) was obtained by incorporating a Schiff base-based fluorescent receptor into the pore walls of mesoporous silica, which exhibited a well ordered mesoporous structure and excellent optical properties demonstrated by various characterization results. SCN-PMO possessed high selectivity and sensitivity towards Cu²⁺ based on its specific fluorescence response. The detection limit of SCN-PMO could be as low as 6.7 × 10^-7 M. Due to protection of the silica network, SCN chromophores in PMOs exhibited higher photostability and the resulting material possessed great repeatability. Additionally, the fluorescence changes of SCN-PMO towards copper ions in vivo (zebrafish) showed that SCN-PMO has potential application as a nanoprobe in biological fields.

Mesoporous Nanostructures Encapsulated with Metallic Nanodots for Smart SERS Sensing

In virtue of uniform mesopores and core-shell nanoarchitectures, metallic nanodot-encapsulated hollow mesoporous nanostructures have shown promising potential in various applications. However, their fabrication with versatile tunability of the encapsulated metallic content has been a challenge. Herein, we have prepared metallic nanodot-encapsulated hollow mesoporous silica nanoparticles (M-HMSNPs) with adjustable inner metallic components. The sacrificial template of polystyrene (PS) nanoparticles precoated with metals (Au/Ag/Pt) is fully wrapped with mesoporous silica (mSiO₂). The metallic nanodots are formed during the template removal process by calcination. The type and content of the encapsulated nanodots can be readily and precisely controlled by the initially deposited metallic layers. We demonstrate the application of the gold (Au) nanodot-loaded HMSNPs (denoted Au-HMSNPs) as smart surface-enhanced Raman spectroscopy (SERS) probes, which can screen between big molecules and small analytes. With the aid of a Raman reporter, the SERS probe can successfully quantify H₂O₂, which is used to distinguish cancer cells in vitro. Further integrated with enzymes, the SERS chips of specificity are prepared and used to detect corresponding substrates of glucose and uric acid, responsively. Besides SERS sensing, the current strategy can inspire future development of many other M-HMSNPs for various applications such as catalysis, energy storage, theranostics, etc.

Robust fluorescent amphiphilic polymer micelle for drug carrier application

The prepared micelles DPOA possessed good biocompatibility, robust stability, and high fluorescent property. The introduction of fluorescent dye made the amphiphilic copolymer obtain the ability of bioimaging to monitor the transport of drug carriers.

Mechanically Reinforced Localized Structure Design to Stabilize Solid-Electrolyte Interface of the Composited Electrode of Si Nanoparticles and TiO2 Nanotubes

Silicon anode with extremely high theoretical specific capacity (≈4200 mAh g^-1 ), experiences huge volume changes during Li-ion insertion and extraction, causing mechanical fracture of Si particles and the growth of a solid-electrolyte interface (SEI), which results in a rapid capacity fading of Si electrodes. Herein, a mechanically reinforced localized structure is designed for carbon-coated Si nanoparticles (C@Si) via elongated TiO₂ nanotubes networks toward stabilizing Si electrode via alleviating mechanical strain and stabilizing the SEI layer. Benefited from the rational localized structure design, the carbon-coated Si nanoparticles/TiO₂ nanotubes composited electrode (C@Si/TiNT) exhibits an ideal electrode thickness swelling, which is lower than 1% after the first cycle and increases to about 6.6% even after 1600 cycles. While for traditional C@Si/carbon nanotube composited electrode, the initial swelling ratio is about 16.7% and reaches ≈190% after 1600 cycles. As a result, the C@Si/TiNT electrode exhibits an outstanding capacity of 1510 mAh g^-1 at 0.1 A g^-1 with high rate capability and long-time cycling performance with 95% capacity retention after 1600 cycles. The rational design on mechanically reinforced localized structure for silicon electrode will provide a versatile platform to solve the current bottlenecks for other alloyed-type electrode materials with large volume expansion toward practical applications.

Tackling Complex Analytical Tasks: An ISO/TS-Based Validation Approach for Hydrodynamic Chromatography Single Particle Inductively Coupled Plasma Mass Spectrometry

Nano-carrier systems such as liposomes have promising biomedical applications. Nevertheless, characterization of these complex samples is a challenging analytical task. In this study a coupled hydrodynamic chromatography-single particle-inductively coupled plasma mass spectrometry (HDC-spICP-MS) approach was validated based on the technical specification (TS) 19590:2017 of the international organization for standardization (ISO). The TS has been adapted to the hyphenated setup. The quality criteria (QC), e.g., linearity of the calibration, transport efficiency, were investigated. Furthermore, a cross calibration of the particle size was performed with values from dynamic light scattering (DLS) and transmission electron microscopy (TEM). Due to an additional Y-piece, an online-calibration routine was implemented. This approach allows the calibration of the ICP-MS during the dead time of the chromatography run, to reduce the required time and enhance the robustness of the results. The optimized method was tested with different gold nanoparticle (Au-NP) mixtures to investigate the characterization properties of HDC separations for samples with increasing complexity. Additionally, the technique was successfully applied to simultaneously determine both the hydrodynamic radius and the Au-NP content in liposomes. With the established hyphenated setup, it was possible to distinguish between different subpopulations with various NP loads and different hydrodynamic diameters inside the liposome carriers.

Supramolecular nanomaterials based on hollow mesoporous drug carriers and macrocycle-capped CuS nanogates for synergistic chemo-photothermal therapy

Multifunctional supramolecular nanoplatforms that integrate the advantages of different therapeutic techniques can trigger multimodal synergistic treatment of tumors, thus representing an emerging powerful tool for cancer therapeutics. Methods: In this work, we design and fabricate a multifunctional supramolecular drug delivery platform, namely Fa-mPEG@CP5-CuS@HMSN-Py nanoparticles (FaPCH NPs), consisting of a pyridinium (Py)-modified hollow mesoporous silica nanoparticles-based drug reservoir (HMSN-Py) with high loading capacity, a layer of NIR-operable carboxylatopillar[5]arene (CP5)-functionalized CuS nanoparticles (CP5-CuS) on the surface of HMSN-Py connected through supramolecular host-guest interactions between CP5 rings and Py stalks, and another layer of folic acid (Fa)-conjugated polyethylene glycol (Fa-PEG) antennas by electrostatic interactions capable of active targeting at tumor lesions, in a controlled, highly integrated fashion for synergistic chemo-photothermal therapy. Results: Fa-mPEG antennas endowed the enhanced active targeting effect toward cancer cells, and CP5-CuS served as not only a quadruple-stimuli responsive nanogate for controllable drug release but also a special agent for NIR-guided photothermal therapy. Meanwhile, anticancer drug doxorubicin (DOX) could be released from the HMSN-Py reservoirs under tumor microenvironments for chemotherapy, thus realizing multimodal synergistic therapeutics. Such a supramolecular drug delivery platform showed effective synergistic chemo-photothermal therapy both in vitro and in vivo. Conclusion: This novel supramolecular nanoplatform possesses great potential in controlled drug delivery and tumor cellular internalization for synergistic chemo-photothermal therapy, providing a promising approach for multimodal synergistic cancer treatment.

Safranin O-functionalized cuboid mesoporous silica material for fluorescent sensing and adsorption of permanganate

A new safranin O-based chelating fluorophore coupled, dual-functionalized organic–inorganic hybrid material has been prepared for simultaneous MnO₄⁻ detection and adsorption in aqueous media and living organisms such as limnodrilus claparedianus and zebrafish.