Ultrasensitive CCL2 Detection in Urine for Diabetic Nephropathy Diagnosis Using a WS2-Based Plasmonic Biosensor.

The accurate diagnosis of diabetic nephropathy relies on achieving ultrasensitive biosensing for biomarker detection. However, existing biosensors face challenges such as poor sensitivity, complexity, time-consuming procedures, and high assay costs. To address these limitations, we report a WS2-based plasmonic biosensor for the ultrasensitive detection of biomarker candidates in clinical human urine samples associated with diabetic nephropathy. Leveraging plasmonic-based electrochemical impedance microscopy (P-EIM) imaging, we observed a remarkable charge sensitivity in monolayer WS2 single crystals. Our biosensor exhibits an exceptionally low detection limit (0.201 ag/mL) and remarkable selectivity in detecting CC chemokine ligand 2 (CCL2) protein biomarkers, outperforming conventional techniques such as ELISA. This work represents a breakthrough in traditional protein sensors, providing a direction and materials foundation for developing ultrasensitive sensors tailored to clinical applications for biomarker sensing.

High-Active Surface of Centimeter-Scale ß-In2S3 for Attomolar-Level Hg2+ Sensing.

Recognition layer materials play a crucial role in the functionality of chemical sensors. Although advancements in two-dimensional (2D) materials have promoted sensor development, the controlled fabrication of large-scale recognition layers with highly active sites remains crucial for enhancing sensor sensitivity, especially for trace detection applications. Herein, we propose a strategy for the controlled preparation of centimeter-scale non-layered ultrathin ß-In2S3 materials with tailored high-active sites to design ultrasensitive Hg2+ sensors. Our results reveal that the highly active sites of non-layered ß-In2S3 materials are pivotal for achieving superior sensing performance. Selective detection of Hg2+ at the 1 aM level is achieved via selective Hg-S bonding. Additionally, we evaluate that this sensor exhibits excellent performance in detecting Hg2+ in the tap water matrix. This work provides a proof-of-concept for utilizing non-layered 2D films in high-performance sensors and highlights their potential for diverse analyte sensing applications.

Multifunctional Biodegradable Conductive Hydrogel Regulating Microenvironment for Stem Cell Therapy Enhances the Nerve Tissue Repair.

The nerve guidance conduits incorporated with stem cells, which can differentiate into the Schwann cells (SCs) to facilitate myelination, shows great promise for repairing the severe peripheral nerve injury. The innovation of advanced hydrogel materials encapsulating stem cells, is highly demanded for generating supportive scaffolds and adaptive microenvironment for nerve regeneration. Herein, this work demonstrates a novel strategy in regulating regenerative microenvironment for peripheral nerve repair with a biodegradable conductive hydrogel scaffold, which can offer multifunctional capabilities in immune regulation, enhancing angiogenesis, driving SCs differentiation, and promoting axon regrowth. The biodegradable conductive hydrogel is constructed by incorporation of polydopamine-modified silicon phosphorus (SiP@PDA) nanosheets into a mixture of methacryloyl gelatin and decellularized extracellular matrix (GelMA/ECM). The biomimetic electrical microenvironment performs an efficacious strategy to facilitate macrophage polarization toward a pro-healing phenotype (M2), meanwhile the conductive hydrogel supports vascularization in regenerated tissue through sustained Si element release. Furthermore, the MSCs 3D-cultured in GelMA/ECM-SiP@PDA conductive hydrogel exhibits significantly increased expression of genes associated with SC-like cell differentiation, thus facilitating the myelination and axonal regeneration. Collectively, both the in vitro and in vivo studies demonstrates that the rationally designed biodegradable multifunctional hydrogel significantly enhances nerve tissues repair.

Ferroelectric Bi2O2Te-Based Plasmonic Biosensor for Ultrasensitive Biomolecular Detection.

Ultrasensitive detection of biomarkers, particularly proteins, and microRNA, is critical for disease early diagnosis. Although surface plasmon resonance biosensors offer label-free, real-time detection, it is challenging to detect biomolecules at low concentrations that only induce a minor mass or refractive index change on the analyte molecules. Here an ultrasensitive plasmonic biosensor strategy is reported by utilizing the ferroelectric properties of Bi2O2Te as a sensitive-layer material. The polarization alteration of ferroelectric Bi2O2Te produces a significant plasmonic biosensing response, enabling the detection of charged biomolecules even at ultralow concentrations. An extraordinary ultralow detection limit of 1 fm is achieved for protein molecules and an unprecedented 0.1 fm for miRNA molecules, demonstrating exceptional specificity. The finding opens a promising avenue for the integration of 2D ferroelectric materials into plasmonic biosensors, with potential applications spanning a wide range.

Manipulation of the polarization state of the focus based on a slab plasmon waveguide.

A focusing nanostructure with tailored polarization properties based on a metal-dielectric slab waveguide combined with plasmonic slits and gratings is proposed. The polarization state of the focus light can be controlled with overlapping a transverse magnetic (TM) focus and a transverse electric (TE) focus, which are formed by focusing the waveguide modes into free space via grating coupling, extraordinary transmission, and plasmonic beaming. We demonstrated that it is possible to achieve either multiple foci or a single focal spot of the transmitted light with tailored polarization states by judicious design of the structure parameter and the polarization state of the incident light.

Biomimetic bone-periosteum scaffold for spatiotemporal regulated innervated bone regeneration and therapy of osteosarcoma.

The complexity of repairing large segment defects and eradicating residual tumor cell puts the osteosarcoma clinical management challenging. Current biomaterial design often overlooks the crucial role of precisely regulating innervation in bone regeneration. Here, we develop a Germanium Selenium (GeSe) co-doped polylactic acid (PLA) nanofiber membrane-coated tricalcium phosphate bioceramic scaffold (TCP-PLA/GeSe) that mimics the bone-periosteum structure. This biomimetic scaffold offers a dual functionality, combining piezoelectric and photothermal conversion capabilities while remaining biodegradable. When subjected to ultrasound irradiation, the US-electric stimulation of TCP-PLA/GeSe enables spatiotemporal control of neurogenic differentiation. This feature supports early innervation during bone formation, promoting early neurogenic differentiation of Schwann cells (SCs) by increasing intracellular Ca2+ and subsequently activating the PI3K-Akt and Ras signaling pathways. The biomimetic scaffold also demonstrates exceptional osteogenic differentiation potential under ultrasound irradiation. In rabbit model of large segment bone defects, the TCP-PLA/GeSe demonstrates promoted osteogenesis and nerve fibre ingrowth. The combined attributes of high photothermal conversion capacity and the sustained release of anti-tumor selenium from the TCP-PLA/GeSe enable the synergistic eradication of osteosarcoma both in vitro and in vivo. This strategy provides new insights on designing advanced biomaterials of repairing large segment bone defect and osteosarcoma.

An Ultrasensitive Plasmonic Sensor Based on 2D Ferroelectric Bi2 O2 Se.

Plasmonic biosensing is a label-free detection method that is commonly used to measure various biomolecular interactions. However, one of the main challenges in this approach is the ability to detect biomolecules at low concentrations with sufficient sensitivity and detection limits. Here, 2D ferroelectric materials are employed to address the issues with sensitivity in biosensor design. A plasmonic sensor based on Bi2 O2 Se nanosheets, a ferroelectric 2D material, is presented for the ultrasensitive detection of the protein molecule. Through imaging the surface charge density of Bi2 O2 Se, a detection limit of 1 fM is achieved for bovine serum albumin (BSA). These findings underscore the potential of ferroelectric 2D materials as critical building blocks for future biosensor and biomaterial architectures.

FePSe3 -Nanosheets-Integrated Cryogenic-3D-Printed Multifunctional Calcium Phosphate Scaffolds for Synergistic Therapy of Osteosarcoma.

Clinical treatment of osteosarcoma encounters great challenges of postsurgical tumor recurrence and extensive bone defect. To develop an advanced artificial bone substitute that can achieve synergistic bone regeneration and tumor therapy for osteosarcoma treatment, a multifunctional calcium phosphate composite enabled by incorporation of bioactive FePSe3 -nanosheets within the cryogenic-3D-printed α-tricalcium phosphate scaffold (TCP-FePSe3 ) is explored. The TCP-FePSe3 scaffold exhibits remarkable tumor ablation ability due to the excellent NIR-II (1064 nm) photothermal property of FePSe3 -nanosheets. Moreover, the biodegradable TCP-FePSe3 scaffold can release selenium element to suppress tumor recurrence by activating of the caspase-dependent apoptosis pathway. In a subcutaneous tumor model, it is demonstrated that tumors can be efficiently eradicated via the combination treatment with local photothermal ablation and the antitumor effect of selenium element. Meanwhile, in a rat calvarial bone defect model, the superior angiogenesis and osteogenesis induced by TCP-FePSe3 scaffold have been observed in vivo. The TCP-FePSe3 scaffold possesses improved capability to promote the repair of bone defects via vascularized bone regeneration, which is induced by the bioactive ions of Fe, Ca, and P released during the biodegradation of the implanted scaffolds. The TCP-FePSe3 composite scaffolds fabricated by cryogenic-3D-printing illustrate a distinctive strategy to construct multifunctional platform for osteosarcoma treatment.

Pressure effect on the magnetism and crystal structure of magnetoelectric metal-organic framework [CH3NH3][Co(HCOO)3].

[CH3NH3][Co(HCOO)3] is the first perovskite-like metal-organic framework exhibiting spin-driven magnetoelectric effects. However, the high-pressure tuning effects on the magnetic properties and crystal structure of [CH3NH3][Co(HCOO)3] have not been studied. In this work, alongside ac magnetic susceptibility measurements, we investigate the magnetic transition temperature evolution under high pressure. Upon increasing the pressure from atmospheric pressure to 0.5 GPa, TN (15.2 K) remains almost unchanged. Continuing to compress the sample results in TN gradually decreasing to 14.8 K at 1.5 GPa. This may be due to pressure induced changes in the bond distance and bond angle of the O-C-O superexchange pathway. In addition, by using high pressure powder X-ray diffraction and Raman spectroscopy, we conducted in-depth research on the pressure dependence of the lattice parameters and Raman modes of [CH3NH3][Co(HCOO)3]. The increase in pressure gives rise to a phase transition from the orthorhombic Pnma to a monoclinic phase at approximately 6.13 GPa. Our study indicates that high pressure can profoundly alter the crystal structure and magnetic properties of perovskite type MOF materials, which could inspire new endeavors in exploring novel phenomena in compressed metal-organic frameworks.

Pressure Control of the Structure and Multiferroicity in a Hydrogen-Bonded Metal-Organic Framework.

Multiferroic materials with the cross-coupling of magnetic and ferroelectric orders provide a new platform for physics study and designing novel electronic devices. However, the weak coupling strength of ferroelectricity and magnetism is the main obstacle for potential applications. The recent research focuses on enhancing the coupling effect via synthesizing novel materials in a chemical route or tuning the multiferroicity in the physical way. Among them, pressure is an effective method to modify multiferroic materials, especially when the chemical doping has reached its tuning limit. In this work, we systemically studied the multiferroic properties in a hydrogen-bonded metal-organic framework (MOF) [(CH3)2NH2]Ni(HCOO)3 under high pressure. X-ray diffraction and Raman scattering reveal that a structural phase transition occurs in a pressure region of 6-9 GPa, and the crystal structure is greatly modified by pressure. With the ac magnetic susceptibility, pyroelectric current, and dielectric constant measurements, we obtain the multiferroic property evolution under high pressure and create a temperature-pressure phase diagram. Our study demonstrates that the pressure can modify the magnetic superexchange interaction and hydrogen bonding simultaneously in these perovskite-like MOFs. The multiferroic phase region has been expanded to higher temperature due to the pressure-enhanced spin-phonon coupling effect.

Direct one-step synthesis of CoFex@Co@C hybrids derived from a metal organic framework for a lightweight and high-performance microwave absorber.

It involves invariably strong expectations and a tough challenge to explore lightweight microwave absorption materials with high efficiency and agile tenability. Here, we successfully synthesized CoFex@Co nanoparticles embedded into a carbon matrix that was directly derived from the metal organic frameworks (MOFs) via a facile method. Benefiting from the unique multi-dimensional construction and synergistic effects of carbon material with magnetic nanoparticles in both the electromagnetic energy loss and impedance matching, CoFe0.26@Co@C composite exhibited excellent microwave absorption performance, which showed a minimum reflection loss of -62.5 dB at the thickness of 1.5 mm and a broad absorption bandwidth of 14.7 GHz exceeding -10 dB at the thickness range of 1.4 to 5 mm. This study not only provides a reference for future preparation of MOF-based lightweight microwave absorption materials, but also offers the possible application owing to its simple procedure and outstanding absorption properties.

Liquid-exfoliation of S-doped black phosphorus nanosheets for enhanced oxygen evolution catalysis.

Black phosphorus (BP) has recently drawn great attention in the field of electrocatalysis due to its distinct electrocatalytic activity for the oxygen evolution reaction (OER). However, the slow OER kinetics and the poor environmental stability of BP seriously limits its overall OER performance and prevents its electrocatalysis application. Here, sulfur (S)-doped BP nanosheets, which are prepared using high-pressure synthesis followed by liquid exfoliation, have been demonstrated to have much better OER electrocatalytic activity and environmental stability compared to their undoped counterparts. The S-doped BP nanosheets display a Tafel slope of 75 mV dec-1, which is a favorable value refered to the kinetics of OER in electrochemical tests. Notably, there is no degradation of S-doped BP nanosheets after six days exposure to ambient, indicating an excellent environmental stability of the S-doped BP. The density functional theory calculations show that the OER activity of BP originate from its crystal defects and heteroatom S doping can effectively enhance its OER activity and stability. These results highlight the doping effect on electrocatalytic activities and stability of BP and provide a simple and effective method to design highly efficient OER catalysts based on the modification of BP.

Effect of layer and stacking sequence in simultaneously grown 2H and 3R WS2 atomic layers.

In two-dimensional layered materials, layer number and stacking order have strong effects on the optical and electronic properties. Tungsten disulfide (WS2) crystal, as one important member among transition metal dichalcogenides, has been usually prepared in a layered 2H prototype structure with space group P63/mmc ([Formula: see text]) in spite of many other expected ones such as 3R. Here, we report simultaneous growth of 2H and 3R stacked multilayer (ML) WS2 crystals in large scale by chemical vapor deposition and effects of layer number and stacking order on optical and electronic properties. As revealed in Raman and photoluminescence (PL) measurements, with an increase in layer number, 2H and 3R stacked ML WS2 crystals show similar variation of PL and Raman peaks in position and intensity. Compared to 2H stacked ML WS2, however, 3R stacked one always exhibits the larger red (blue) shift of Raman [Formula: see text] (A1g) peak and the appearance of PL A, B and I peaks at lower energies. Thereby, PL and Raman features depend on not only layer number but also stacking order. In addition, circularly polarized luminescence from two prototype WS2 crystals under circularly polarized excitation has also been investigated, showing obvious spin or valley polarization of these CVD-grown multilayer WS2 crystals.

Superior microwave absorption properties of ultralight reduced graphene oxide/black phosphorus aerogel.

Through a facile self-assembled process, an ultralight reduced graphene oxide/black phosphorus (rGO/BP) composite aerogel was successfully fabricated. The BP nanosheets were homogeneously distributed throughout the rGO 3D framework, and the interfaces between rGO and BP possessed four kinds of interconnections, such as wrapping, wearing, bridging and weak linking. As an ultralight composite, the rGO/BP aerogel could easily stand on the stamen of a flower. Compared with pure rGO aerogel, the rGO/BP composite aerogel exhibited enhanced microwave absorption ability. The minimum reflection loss value of -46.9 dB with a thickness of 2.53 mm was obtained, and a wide absorption band of 6.1 GHz (RL < -10 dB) was achieved. The superior microwave absorption property was demonstrated to stem from the interfacial polarization loss mechanism in which the multiform interface interactions between the rGO skeleton and BP nanosheets played critical roles. The rGO/BP aerogel has great potential to be used as an ultralight microwave absorber.

Two-dimensional materials and one-dimensional carbon nanotube composites for microwave absorption.

In this work, hierarchical architecture MoS2/CNT nanohybrids synthesized by the hydrothermal method, with different CNT proportions are systematically investigated for their microwave absorption. MoS2 nanoflowers are anchored uniformly on the surface of a CNT when the proportion of the MoS2/CNT nanohybrids was 10:2, and the reflection loss can attain -20 dB in the range of 3.4-13.9 GHz with multiple thicknesses from 1.5-5.0 mm, while an optimal consequence of -46 dB can be reached at 6.6 GHz at 2.9 mm. The excellent performance indicates that the MoS2/CNT = 10:2 nanohybrids have the potential for use as microwave absorbing materials.

Grain wall boundaries in centimeter-scale continuous monolayer WS2 film grown by chemical vapor deposition.

Centimeter-scale continuous monolayer WS2 film with large tensile strain has been successfully grown on oxidized silicon substrate by chemical vapor deposition, in which monolayer grains can be more than 200 µm in size. Monolayer WS2 grains are observed to merge together via not only traditional grain boundaries but also non-traditional ones, which are named as grain walls (GWs) due to their nanometer-scale widths. The GWs are revealed to consist of two or three layers. Though not a monolayer, the GWs exhibit significantly enhanced fluorescence and photoluminescence. This enhancement may be attributed to abundant structural defects such as stacking faults and partial dislocations in the GWs, which are clearly observable in atomically resolved high resolution transmission electron microscopy and scanning transmission electron microscopy images. Moreover, GW-based phototransistor is found to deliver higher photocurrent than that based on monolayer film. These features of GWs provide a clue to microstructure engineering of monolayer WS2 for specific applications in (opto)electronics.

Metal-organic framework derived cobalt phosphosulfide with ultrahigh microwave absorption properties.

Nanostructure composites of ferromagnetic materials embedded in nanoporous carbon (NC) derived from metal-organic frameworks (MOFs) have attracted enormous attention due to their potential application in many fields, such as microwave absorption, energy storage, and conversion. The rational design of nanocomposites holds a determinant factor for overcoming the challenges involving the microwave absorption performance. Herein, CoS2/NC, CoP/NC, and CoS2-xPx/NC with a rhombic dodecahedral structure have been successfully fabricated by using the template cobalt-based MOFs (ZIF-67). A morphology analysis indicates that ferromagnetic nanoparticles are embedded in NC matrix. It is obvious that the rhombic dodecahedron can be maintained after the phosphorization and sulfurization of Co/NC derived from the thermal decomposition of ZIF-67. The microwave absorption performance can obviously be improved by the phosphorization and sulfurization of Co/NC. CoS2-xPx/NC exhibits an excellent microwave absorption property and the minimum reflection loss (RL) of CoS2-xPx/NC can reach -68 dB at 14.6 GHz with a thickness of 1.5 mm. An RL value less than -10 dB can be achieved in the microwave frequency range of 12.7-17.3 GHz (4.6 GHz) with a thickness of 1.5 mm for CoS2-xPx/NC. This article offers a novel way to fabricate cobalt-based materials/carbon composites for an excellent microwave absorber.

High-Performance Broadband Image Sensing Photodetector Based on MnTe/WS2 van der Waals Epitaxial Heterostructures.

Two-dimensional transition metal dichalcogenide (TMDC) heterostructure is receiving considerable attention due to its novel electronic, optoelectronic, and spintronic devices with design-oriented and functional features. However, direct design and synthesis of high-quality TMDC/MnTe heterostructures remain difficult, which severely impede further investigations of semiconductor/magnetic semiconductor devices. Herein, the synthesis of high-quality vertically stacked WS2/MnTe heterostructures is realized via a two-step chemical vapor deposition method. Raman, photoluminescence, and scanning transmission electron microscopy characterizations reveal the high-quality and atomically sharp interfaces of the WS2/MnTe heterostructure. WS2/MnTe-based van der Waals field effect transistors demonstrate high rectification behavior with rectification ratio up to 106, as well as a typical p-n electrical transport characteristic. Notably, the fabricated WS2/MnTe photodetector exhibits sensitive and broadband photoresponse ranging from UV to NIR with a maximum responsivity of 1.2 × 103 A/W, a high external quantum efficiency of 2.7 × 105%, and fast photoresponse time of ∼50 ms. Moreover, WS2/MnTe heterostructure photodetectors possess a broadband image sensing capability at room temperature, suggesting potential applications in next-generation high-performance and broadband image sensing photodetectors.

Plasmonic Imaging of Single DNA with Charge Sensitive Monolayer WS2.

Imaging the surface charge of biomolecules such as proteins and DNA, is crucial for comprehending their structure and function. Unfortunately, current methods for label-free, sensitive, and rapid imaging of the surface charge of single DNA molecules are limited. Here, we propose a plasmonic microscopy strategy that utilizes charge-sensitive single-crystal monolayer WS2 materials to image the local charge density of a single λ-DNA molecule. Our study reveals that WS2 is a highly sensitive charge-sensitive material that can accurately measure the local charge density of λ-DNA with high spatial resolution and sensitivity. The consistency of the surface charge density values obtained from the single-crystal monolayer WS2 materials with theoretical simulations demonstrates the reliability of our approach. Our findings suggest that this class of materials has significant implications for the development of label-free, scanning-free, and rapid optical detection and charge imaging of biomolecules.

Atomic-Level Defect Engineering in GeP Nanoflake Biosensors for Gastric Cancer Diagnosis.

Defect engineering offers a promising approach to enhance the sensitivity of biosensing materials by creating abundant chemically active sites. Despite its potential, achieving precise control and modification of these defects remains a significant challenge. Herein, we propose atomic-level defect engineering in GeP two-dimensional (2D) layered materials, following precise in situ growing Au nanoparticles on the single defect active sites for the design of ultrasensitive biosensors. The GeP-based biosensor exhibits notable capabilities for miRNA detection with excellent chemical stability, sensitivity, selectivity, and an extremely low detection limit of 28.6 aM. When applied to clinical tissue samples from gastric cancer patients, the biosensor effectively quantified the miR378c biomarker, enabling accurate stage-specific monitoring. This research not only represents a crucial advancement in the field of biosensing materials through defect engineering but also provides a promising avenue for early cancer diagnosis, staging, and monitoring.