Photoluminescence Architectures for Disease Diagnosis: From Graphene to Thin-Layer Transition Metal Dichalcogenides and Oxides

Using tungsten oxide quantum-dot enhanced electrochemiluminescence to measure thrombin activity and screen its inhibitors

A thrombin-activity-based electrochemiluminescence (ECL) biosensor was successfully constructed using tungsten oxide quantum dots (WO3-x QDS) as the co-reactant and thrombin-cleavable peptides as the recognizer. Specifically, Ru(bpy)32+ were doped on silica nanoparticles (Ru@SiO2), which greatly enhanced the ECL potential. AuNPs@WO3-x QDs composite was then prepared to accelerate electron transfer and improve the ECL signal by 219 times. Under ideal conditions, the limit of detection for thrombin in serum was determined to be 0.28 μU/mL with a linear range from 1 μU/mL to 1 U/mL. In addition, the developed ECL biosensor was used to screen for thrombin inhibitors from 12 compounds in Artemisiae Argyi Folium. Among the compounds tested, it was observed that 100 μmol/L luteolin exhibited a significantly higher inhibition rate (exceeding 80%) compared to apigenin, isorhamnetin, naringin, or eriodictyol. In an in-vitro anticoagulation experiment, luteolin (100 μmol/L) prolonged APTT by 49%, and the molecular docking assay indicated that luteolin had binding sites of Gly219 and Asp189 in the active pockets of thrombin. This may have been the main reason underpinning luteolin's anticoagulation effects. Overall, the Ru@WO3-x QDS ECL biosensor provided a reliable strategy for thrombin activity assay and screening of anticoagulant agents.

MoS2 Defect Healing for High-Performance Chemical Sensing of Polycyclic Aromatic Hydrocarbons

The increasing population and industrial development are responsible for environmental pollution. Among toxic chemicals, polycyclic aromatic hydrocarbons (PAHs) are highly carcinogenic contaminants resulting from the incomplete combustion of organic materials. Two-dimensional materials, such as transition metal dichalcogenides (TMDCs), are ideal sensory scaffolds, combining high surface-to-volume ratio with physical and chemical properties that are strongly susceptible to environmental changes. TMDCs can be integrated in field-effect transistors (FETs), which can operate as high-performance chemical detectors of (non)covalent interaction with small molecules. Here, we have developed MoS₂-based FETs as platforms for PAHs sensing, relying on the affinity of the planar polyaromatic molecules for the basal plane of MoS₂ and the structural defects in its lattice. X-ray photoelectron spectroscopy analysis, photoluminescence measurements, and transfer characteristics showed a notable reduction in the defectiveness of MoS₂ and a p-type doping upon exposure to PAHs solutions, with a magnitude determined by the correlation between the ionization energies (E_I) of the PAH and that of MoS₂. Naphthalene, endowed with the higher E_I among the studied PAHs, exhibited the highest output. We observed a log-log correlation between MoS₂ doping and naphthalene concentration in water in a wide range (10^-9-10^-6 M), as well as a reversible response to the analyte. Naphthalene concentrations as low as 0.128 ppb were detected, being below the limits imposed by health regulations for drinking water. Furthermore, our MoS₂ devices can reversibly detect vapors of naphthalene with both an electrical and optical readout, confirming that our architecture could operate as a dual sensing platform.

Progress on two-dimensional binary oxide materials

Two-dimensional van der Waals (2D vdW) materials have attracted much attention because of their unique electronic and optical properties. Since the successful isolation of graphene in 2004, many interesting 2D materials have emerged, including elemental olefins (silicene, germanene, etc.), transition metal chalcogenides, transition metal carbides (nitrides), hexagonal boron, etc. On the other hand, 2D binary oxide materials are an important group in the 2D family owing to their high structural diversity, low cost, high stability, and strong adjustability. This review systematically summarizes the research progress on 2D binary oxide materials. We discuss their composition and structure in terms of vdW and non-vdW categories in detail, followed by a discussion of their synthesis methods. In particular, we focus on strategies to tailor the properties of 2D oxides and their emerging applications in different fields. Finally, the challenges and future developments of 2D binary oxides are provided.

Targeted delivery of maytansine to liver cancer cells via galactose-modified supramolecular two-dimensional glycomaterial

A two-dimensional (2D) glycomaterial for targeted delivery of maytansine to liver cancer cells was developed. Host-guest interaction between a galactosyl dye and human serum albumin (HSA) produces supramolecular galactoside-HSA conjugates, which are then used to coat 2D MoS₂. The 2D glycomaterial was shown to be capable of the targeted delivery of maytansine to a liver cancer cell line that highly expresses a galactose receptor, resulting in greater cytotoxicity than maytansine alone.

Multifunctional carbon nanomaterials for diagnostic applications in infectious diseases and tumors

Infectious diseases (such as Corona Virus Disease 2019) and tumors pose a tremendous challenge to global public health. Early diagnosis of infectious diseases and tumors can lead to effective control and early intervention of the patient's condition. Over the past few decades, carbon nanomaterials (CNs) have attracted widespread attention in different scientific disciplines. In the field of biomedicine, carbon nanotubes, graphene, carbon quantum dots and fullerenes have the ability of improving the accuracy of the diagnosis by the improvement of the diagnostic approaches. Therefore, this review highlights their applications in the diagnosis of infectious diseases and tumors over the past five years. Recent advances in the field of biosensing, bioimaging, and nucleic acid amplification by such CNs are introduced and discussed, emphasizing the importance of their unique properties in infectious disease and tumor diagnosis and the challenges and opportunities that exist for future clinical applications. Although the application of CNs in the diagnosis of several diseases is still at a beginning stage, biosensors, bioimaging technologies and nucleic acid amplification technologies built on CNs represent a new generation of promising diagnostic tools that further support their potential application in infectious disease and tumor diagnosis.

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Carbon nanomaterials (CNs) are systematically introduced in this review.

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This review studies the application of CNs in infectious diseases and tumors diagnosis.

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CNs act as potent nanostructures for biosensing, bioimaging, & nucleic acid amplification.

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New CN-based detection methods were introduced to detect SARS-CoV-2.

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The challenges and prospects of CN-based diagnostic assays are also discussed.

Graphene Biodevices for Early Disease Diagnosis Based on Biomarker Detection

The early diagnosis of diseases plays a vital role in healthcare and the extension of human life. Graphene-based biosensors have boosted the early diagnosis of diseases by detecting and monitoring related biomarkers, providing a better understanding of various physiological and pathological processes. They have generated tremendous interest, made significant advances, and offered promising application prospects. In this paper, we discuss the background of graphene and biosensors, including the properties and functionalization of graphene and biosensors. Second, the significant technologies adopted by biosensors are discussed, such as field-effect transistors and electrochemical and optical methods. Subsequently, we highlight biosensors for detecting various biomarkers, including ions, small molecules, macromolecules, viruses, bacteria, and living human cells. Finally, the opportunities and challenges of graphene-based biosensors and related broad research interests are discussed.

Graphene-based materials: A new tool to fight against breast cancer

Breast cancer is one of the most common malignant tumors among women population on a global scale, with a huge number of new cases and deaths each year. In recent years, there has been an increasing number of literatures on the discovery and development of novel anti-breast cancer drugs and materials, aiming to increase the survival rate of breast cancer patients. One of the newest tools used for the therapy of breast cancer is graphene-based materials, which have ultra-high surface area as well as unique physical, chemical and mechanical properties. It is reported that graphene-based materials could induce apoptosis in cancer cells while showing low toxicity due to their carbon structure. Therefore, they can be used as nano-drugs or biological carriers to introduce small molecules such as nucleic acids, drugs, or photosensitizers into the human body to achieve treatment goals. This article introduces the synthetic methods for graphene-based materials, as well as the current status and the future prospects of graphene-based materials' application in the treatment of breast cancer.

Graphene and other 2D materials: a multidisciplinary analysis to uncover the hidden potential as cancer theranostics

Cancer represents one of the main causes of death in the world; hence the development of more specific approaches for its diagnosis and treatment is urgently needed in clinical practice. Here we aim at providing a comprehensive review on the use of 2-dimensional materials (2DMs) in cancer theranostics. In particular, we focus on graphene-related materials (GRMs), graphene hybrids, and graphdiyne (GDY), as well as other emerging 2DMs, such as MXene, tungsten disulfide (WS2), molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN), black phosphorus (BP), silicene, antimonene (AM), germanene, biotite (black mica), metal organic frameworks (MOFs), and others. The results reported in the scientific literature in the last ten years (>200 papers) are dissected here with respect to the wide variety of combinations of imaging methodologies and therapeutic approaches, including drug/gene delivery, photothermal/photodynamic therapy, sonodynamic therapy, and immunotherapy. We provide a unique multidisciplinary approach in discussing the literature, which also includes a detailed section on the characterization methods used to analyze the material properties, highlighting the merits and limitations of the different approaches. The aim of this review is to show the strong potential of 2DMs for use as cancer theranostics, as well as to highlight issues that prevent the clinical translation of these materials. Overall, we hope to shed light on the hidden potential of the vast panorama of new and emerging 2DMs as clinical cancer theranostics.

Coupling strand extension/excision amplification with target recycling enables highly sensitive and aptamer-based label-free sensing of ATP in human serum

Detection of aberrant ATP concentrations with high sensitivity and selectivity is of critical importance for monitoring many biological processes and disease stages. By coupling extension/excision amplification with target recycling, we have established an aptamer-based method for label-free fluorescence ATP detection in human serum with high sensitivity. The ATP target molecules associate with the aptamer-containing double hairpin probes and cause conformational changes of the probes to initiate the cyclic strand extension/excision processes in the presence of polymerase, endonuclease and assistance sequences for the recycling of ATP and the production of a large number of G-quadruplex sequences. The organic dye thioflavin T subsequently binds these G-quadruplex sequences to yield substantially enhanced fluorescence emission for achieving highly sensitive detection of ATP down to 2.2 nM in the range of 5 to 200 nM without using any labels. The developed aptamer sensing method also exhibits high selectivity and allows the monitoring of ATP at low concentrations in diluted real samples, which offers promising opportunities to establish effective signal magnification means for the detection of various biomolecules at trace levels.

Construction of Tb-MOF-on-Fe-MOF conjugate as a novel platform for ultrasensitive detection of carbohydrate antigen 125 and living cancer cells

Combining different metal-organic frameworks (MOFs) into a conjugate material can integrate the properties of each MOF component and further lead to emergent properties from the synergistic heterostructured units. In this work, two kinds of bimetallic TbFe-MOFs have been designed by MOF-on-MOF strategy and utilized as a platform for anchoring carbohydrate antigen 125 (CA125) aptamer to detect CA125 and living michigan cancer foundation-7 (MCF-7) cells. Although the integrated MOF-on-MOF architectures show similar chemical and structural features to that of the top layer, the Fe-MOF-on-Tb-MOF and Tb-MOF-on-Fe-MOF have different surface nanostructures to their parent MOFs. The developed aptasensor based on Tb-MOF-on-Fe-MOF displays higher stability of the formed G-quadruplex between aptamer and CA125 than that based on Fe-MOF-on-Tb-MOF, owing to stronger immobilization behavior of the aptamer for the Tb-MOF-on-Fe-MOF composite. The developed aptasensor provides an extremely low detection limit of 58 μU·mL^-1 towards CA125 within a wide linear range from 100 μU·mL^-1 to 200 U·mL^-1, which is significantly lower than those of all reported sensors. This aptasensor also has high selectivity, good stability, acceptable reproducibility, and excellent applicability in human serum. Moreover, the Tb-MOF-on-Fe-MOF nanoarchitecture demonstrates superior biocompatibility and good endocytosis. As a result, the developed aptasensor illustrates high sensitivity for detection of MCF-7 cells with an extremely low detection limit of 19 cell·mL^-1. Therefore, the proposed aptasensor based on Tb-MOF-on-Fe-MOF exhibits great potentials for early diagnosis of tumors.

Self-Assembled Thin-Layer Glycomaterials With a Proper Shell Thickness for Targeted and Activatable Cell Imaging

The construction of targeted and activatable materials can largely improve the precision of disease diagnosis and therapy. However, the currently developed systems either target a transmembrane antigen or are activatable to release imaging and/or therapeutic reagents intracellularly. Here, we develop a simple thin-layer glycomaterial through the self-assembly between fluorescent glycoprobes, in which the carbohydrate-targeting reagent and the fluorophore are linked to each other by polyethylene glycol with a suitable chain length, and thin-layer manganese dioxide. The fluorogenic material developed is both capable of targeting a transmembrane glycoprotein receptor and fluorescently activatable by intracellular biothiols. The shell thickness of the material was determined to be important for achieving the biothiol-induced activation of fluorescence. This research might provide insight into the development of precision-enhanced self-assembled materials for disease theranostics.

Physically-triggered nanosystems based on two-dimensional materials for cancer theranostics

There is an increasing demand to develop effective methods for treating malignant diseases to improve healthcare in our society. Stimuli-responsive nanosystems, which can respond to internal or external stimuli are promising in cancer therapy and diagnosis due to their functionality and versatility. As a newly emerging class of nanomaterials, two-dimensional (2D) nanomaterials have attracted huge interest in many different fields including biomedicine due to their unique physical and chemical properties. In the past decade, stimuli-responsive nanosystems based on 2D nanomaterials have been widely studied, showing promising applications in cancer therapy and diagnosis, including phototherapies, magnetic therapy, drug and gene delivery, and non-invasive imaging. Here, we will focus our attention on the state-of-the-art of physically-triggered nanosystems based on graphene and two-dimensional nanomaterials for cancer therapy and diagnosis. The physical triggers include light, temperature, magnetic and electric fields.

Biocompatibility and toxicity of graphene quantum dots for potential application in photodynamic therapy

Aim: Achieving reliably high production of reactive oxygen species (ROS) in photodynamic therapy (PDT) remains challenging. Graphene quantum dots (GQDs) hold great promise for PDT. However, the photochemical processes leading to GQD-derived ROS generation have not yet been fully elucidated. Materials & methods: Physicochemical characteristics of GQDs were comprehensively investigated, including electron paramagnetic resonance analysis of singlet oxygen production. Dark toxicity was assessed in vitro and in vivo. Results: GQDs demonstrated excellent photoluminescent features, corrosion resistance, high water solubility, high photo/pH-stability, in vitro and in vivo biocompatibility and very efficient singlet oxygen/ROS generation. Conclusion: The enhanced ROS generation, combined with good biocompatibility and minimal toxicity in vitro and in vivo support the potential of GQDs for future PDT application.

Graphene oxide-enhanced cytoskeleton imaging and mitosis tracking

Here we show that graphene oxide greatly enhances the imaging ability of a peptide probe that selectively targets microtubules of the cytoskeleton, thus enabling the dynamic tracking of mitosis in live cells.

Photocontrolled Fluorescence "Double-Check" Bioimaging Enabled by a Glycoprobe-Protein Hybrid

Despite the rapid development of imaging techniques, precise probe localization and modulation in living cells is still a challenging task. Here we show that the simple hybridization between a photochromic fluorescent glycoprobe and human serum albumin (HSA) enables a unique fluorescence "double-check" mechanism for precisely localizing and manipulating probe molecules in living cells. Docking of a carbohydrate-modified naphthalimide (Naph)-spiropyran (SP) dyad to a hydrophobic pocket of HSA produces the glycoprobe-protein hybrid, causing the protein conformation to fold as determined by small-angle X-ray scattering. We show that the Naph and merocyanine (the photoisomer of SP) fluorescence of the resulting hybrid can be reversibly switched by light in buffer solution and in target cells overexpressing the carbohydrate receptor.

Supramolecular glyco-poly-cyclodextrin functionalized thin-layer manganese dioxide for targeted stimulus-responsive bioimaging

We have developed a supramoleuclar imaging probe based on thin-layer manganese dioxide functionalized with a fluorescent, multivalent glyco-poly-cycolodextrin for the targeted, stimulus-responsive bioimaging of cancer cells.

Glypican-3-targeted precision diagnosis of hepatocellular carcinoma on clinical sections with a supramolecular 2D imaging probe

The ability of chemical tools to effectively detect malignancy in frozen sections removed from patients during surgery is important for the timely determination of the subsequent surgical program. However, current clinical methods for tissue imaging rely on dye-based staining or antibody-based techniques, which are sluggish and complicated. Methods: Here, we have developed a 2D material-based supramolecular imaging probe for the simple, rapid yet precise diagnosis of hepatocellular carcinoma (HCC). The 2D probe is constructed through supramolecular self-assembly between a water soluble, fluorescent peptide ligand that selectively targets glypican-3 (GPC-3, a specific cell-surface biomarker for HCC) and 2D molybdenum disulfide that acts as a fluorescence quencher as well as imaging enhancer. Results: We show that the 2D imaging probe developed with minimal background fluorescence can sensitively and selectively image cells overexpressing GPC-3 over a range of control cells expressing other membrane proteins. Importantly, we demonstrate that the 2D probe is capable of rapidly (signal became readable within 1 min) imaging HCC tissues over para-carcinoma regions in frozen sections derived from HCC patients; the results are in accordance with those obtained using traditional clinical staining methods. Conclusion: Compared to conventional staining methods, which are laborious (e.g., over 30 min is needed for antibody-based immunosorbent assays) and complex (e.g., diagnosis is based on discrimination of the nucleus morphology of cancer cells from that of normal cells), our probe, with its simplicity and quickness, might become a promising candidate for tumor-section staining as well as fluorescence imaging-guided surgery.

Insights into the role of nanostructure in the sensing properties of carbon nanodots for improved sensitivity to reactive oxygen species in living cells

The surface states of carbon nanodots (CDs) were engineered by controlling the chemical structure on the surface of the CDs, which play an important role in the chemiluminescence sensing properties of CDs towards peroxynitrite. Their application in monitoring exogenous and endogenous release of peroxynitrite in living cells is demonstrated.

A supramolecular pyrenyl glycoside-coated 2D MoS2 composite electrode for selective cell capture

Here we demonstrate the simple construction and characterization of a pyrenyl glycoside-coated 2D MoS₂ material composite capable of selectively capturing proteins and live cells on an electrode, as determined by differential pulse voltammetry.

Emerging 0D Transition-Metal Dichalcogenides for Sensors, Biomedicine, and Clean Energy

Following research on two-dimensional (2D) transition metal dichalcogenides (TMDs), zero-dimensional (0D) TMDs nanostructures have also garnered some attention due to their unique properties; exploitable for new applications. The 0D TMDs nanostructures stand distinct from their larger 2D TMDs cousins in terms of their general structure and properties. 0D TMDs possess higher bandgaps, ultra-small sizes, high surface-to-volume ratios with more active edge sites per unit mass. So far, reported 0D TMDs can be mainly classified as quantum dots, nanodots, nanoparticles, and small nanoflakes. All exhibited diverse applications in various fields due to their unique and excellent properties. Of significance, through exploiting inherent characteristics of 0D TMDs materials, enhanced catalytic, biomedical, and photoluminescence applications can be realized through this exciting sub-class of TMDs. Herein, we comprehensively review the properties and synthesis methods of 0D TMDs nanostructures and focus on their potential applications in sensor, biomedicine, and energy fields. This article aims to educate potential adopters of these excitingly new nanomaterials as well as to inspire and promote the development of more impactful applications. Especially in this rapidly evolving field, this review may be a good resource of critical insights and in-depth comparisons between the 0D and 2D TMDs.

Molybdenum Disulfide Nanoparticles as Multifunctional Inhibitors against Alzheimer's Disease

The complex pathogenic mechanisms of Alzheimer's disease (AD) include the aggregation of β-amyloid peptides (Aβ) into oligomers or fibrils as well as Aβ-mediated oxidative stress, which require comprehensive treatment. Therefore, the inhibition of Aβ aggregation and free-radical scavenging are essential for the treatment of AD. Nanoparticles (NPs) have been found to influence Aβ aggregation process in vitro. Herein, we report the inhibition effects of molybdenum disulfide (MoS₂) NPs on Aβ aggregation. Polyvinylpyrrolidone-functionalized MoS₂ NPs were fabricated by a pulsed laser ablation method. We find that MoS₂ NPs exhibit multifunctional effects on Aβ peptides: inhibiting Aβ aggregation, destabilizing Aβ fibrils, alleviating Aβ-induced oxidative stress, as well as Aβ-mediated cell toxicity. Moreover, we show that MoS₂ NPs can block the formation of the Ca²⁺ channel induced by Aβ fibrils in the cell membrane for the first time. Thus, these observations suggest that MoS₂ NPs have great potential for a multifunctional therapeutic agent against amyloid-related diseases.

GPCR Activation and Endocytosis Induced by a 2D Material Agonist

Agonist-induced activation and endocytosis of G protein-coupled receptors (GPCRs) are crucial for a number of physiological and pathological processes. However, tools that are available for probing GPCR endocytosis have been insufficient. Here, we developed a two-dimensional (2D) material agonist by supramolecular self-assembly between an endogenous agonist of κ-opioid receptor (KOR) and 2D molybdenum disulfide. The 2D material agonist has proven to be amenable for eliciting GPCR activation and endocytosis in cells stably expressing KOR rather than in those without KOR expression. Using super-resolution microscopy, we also show that the 2D material agonist colocalizes well with GFP-fused KOR intracellularly. Further, the endocytosed 2D material agonist can selectively produce reactive oxygen species in cells that overly express KOR, as controlled by light irradiation.

Effective micro-spray cooling for light-emitting diode with graphene nanoporous layers

A graphene nanoplatelet (GNP) coating is utilized as a functionalized surface in enhancing the evaporation rate of micro-spray cooling for light-emitting diodes (LEDs). In micro-spray cooling, water is atomized into micro-sized droplets to reduce the surface energy and to increase the surface area for evaporation. The GNP coating facilitates the effective filmwise evaporation through the attribute of fast water permeation. The oxygenated functional groups of GNPs provide the driving force that initiates the intercalation of water molecules through the carbon nanostructure. The water molecules slip through the frictionless passages between the hydrophobic carbon walls, resulting an effective filmwise evaporation. The enhancement of evaporation leads to an enormous temperature reduction of 61.3 °C. The performance of the LED is greatly enhanced: a maximum increase in illuminance of 25% and an extension of power rating from 9 W to 12 W can be achieved. With the application of GNP coating, the high-temperature region is eliminated while maintaining the LED surface temperature for optimal operation. This study paves the way for employing the effective hybrid spray-evaporation-nanostructure technique in the development of a compact, low-power-consumption cooling system.

Fluorogenic 2D Peptidosheet Unravels CD47 as a Potential Biomarker for Profiling Hepatocellular Carcinoma and Cholangiocarcinoma Tissues

A 2D peptidosheet unravels CD47 as a potential biomarker to image hepatocarcinoma and cholangiocarcinoma cells and tissues. Supramolecular assembly between water-soluble 2D MoS₂ and a peptide probe produces the 2D peptidosheet suited for the profiling of hepatocarcinoma and cholangiocarcinoma tissues over healthy tissues on clinical specimens.

Multiplexed photoluminescent sensors: towards improved disease diagnostics

This tutorial review highlights the development of multiplexed photoluminescent sensors which can simultaneously detect multiple and diverse biomarkers that exist in a homogenous solution or a single cell, accelerating the progress towards precise disease diagnostics.

Fabrication of graphene nanosheet–multiwalled carbon nanotube–polyaniline modified carbon paste electrode for the simultaneous electrochemical determination of terbutaline sulphate and guaifenesin

A sensitive electrochemical method is developed for the simultaneous determination of terbutaline sulphate (TBS) and guaifenesin (GF) at a carbon paste electrode modified with graphene nanosheet–multiwalled carbon nanotube–polyaniline composite (GNS–MWCNT–PANI).

AIE fluorophore with enhanced cellular uptake for tracking esterase-activated release of taurine and ROS scavenging

Fluorophores with aggregation-induced emission (AIE) characteristics are attractive and versatile tools for both chemical sensing and biological imaging. Herein, we designed and synthesized a fluorescent light-up system CTPE-Tau with enhanced cellular uptake ability. The system possesses several advantages, such as a large Stokes shift, low cytotoxicity, and good photostability. Also, it has been successfully utilized to track esterase-activated release of taurine and to scavenge intracellular ROS, and shows great potential for trackable visualized therapy.

A luminescent metal organic framework with high sensitivity for detecting and removing copper ions from simulated biological fluids

Cd-MOF-74shows high sensitivity and efficiency in the detection and removal of copper ions from water and simulated biological fluids.

Supramolecular assembly of fluorogenic glyco-dots from perylenediimide-based glycoclusters for targeted imaging of cancer cells

Supramolecular self-assembly between perylenediimide-based glycoclusters and a red-emitting fluorophore produces structurally uniform and stable glyco-dots amenable to targeted fluorogenic imaging of liver and triple-negative breast cancer cells.

Vibration-Induced-Emission (VIE) for imaging amyloid β fibrils

This paper discusses the use of N,N′-disubstituted-dihydrodibenzo[a,c]phenazines with typical Vibration-Induced-Emission (VIE) properties for imaging amyloid β (Aβ) fibrils, which are a signature of neurological disorders such as Alzheimer's disease. A water-soluble VIEgen with a red fluorescence emission shows a pronounced, blue-shifted emission with Aβ peptide monomers and fibrils. The enhancement in blue fluorescence can be ascribed to the restriction of the molecular vibration by selectively binding to Aβ. We determine an increasing blue-to-red emission ratio of the VIEgen with both the concentration and fibrogenesis time of Aβ, thereby enabling a ratiometric detection of Aβ in its different morphological forms. Importantly, the VIEgen was proven to be suitable for the fluorescence imaging of small Aβ plaques in the hippocampus of a transgenic mouse brain (five months old), with the blue and red emissions well overlapped on the Aβ. This research offers a new rationale to design molecular VIE probes for biological applications.

Ratiometric Detection of β-Amyloid and Discrimination from Lectins by a Supramolecular AIE Glyconanoparticle

While the development of AIE (aggregation-induced-emission) based fluorimetric probes for biological applications has been an active research area, probes with a ratiometric signal for biomolecular recognition have been rare. Here, a ratiometric AIE glyconanoparticle formed by the supramolecular assembly between a silole-based AIEgen and fluorescent glycoprobes for the detection of amyloid β (Aβ) peptides and fibrils, which are a signature of neurological disorders such as the Alzheimer's disease, is shown. Complexation of glycoprobes with the AIEgen produces an intensive fluorescence emission of the former because of a Förster resonance energy transfer between the two molecules. Subsequently, the presence of Aβ dissembles the particle, producing a fluorescence emission of the AIEgen. Interestingly, the addition of lectins that selectively recognize the glycoprobes results in a different ratiometric response of the particle, thereby enabling a discrimination from Aβ detection. This research offers insight into the simple construction of multifunctional ratiometric probes based on the supramolecular hybridization of a wide variety of AIEgens with fluorescent molecular probes.

Targeted Intracellular Production of Reactive Oxygen Species by a 2D Molybdenum Disulfide Glycosheet

A 2D "glycosheet" based on supramolecular self-assembly between 2D MoS₂ and fluorescent glycoligands is developed. The composite 2D material is proven suitable for targeted intracellular production of reactive oxygen species (singlet oxygen) by the sequential control of a receptor endocytosis and light irradiation.

Graphene oxide as a scaffold for bone regeneration

Graphene oxide (GO), the oxidized form of graphene, holds great potential as a component of biomedical devices, deriving utility from its ability to support a broad range of chemical functionalities and its exceptional mechanical, electronic, and thermal properties. GO composites can be tuned chemically to be biomimetic, and mechanically to be stiff yet strong. These unique properties make GO-based materials promising candidates as a scaffold for bone regeneration. However, questions still exist as to the compatibility and long-term toxicity of nanocarbon materials. Unlike other nanocarbons, GO is meta-stable, water dispersible, and autodegrades in water on the timescale of months to humic acid-like materials, the degradation products of all organic matter. Thus, GO offers better prospects for biological compatibility over other nanocarbons. Recently, many publications have demonstrated enhanced osteogenic performance of GO-containing composites. Ongoing work toward surface modification or coating strategies could be useful to minimize the inflammatory response and improve compatibility of GO as a component of medical devices. Furthermore, biomimetic modifications could offer mechanical and chemical environments that encourage osteogenesis. So long as care is given to assure their safety, GO-based materials may be poised to become the next generation scaffold for bone regeneration. WIREs Nanomed Nanobiotechnol 2017, 9:e1437. doi: 10.1002/wnan.1437 For further resources related to this article, please visit the WIREs website.

Probing Mannose-Binding Proteins That Express on Live Cells and Pathogens with a Diffusion-to-Surface Ratiometric Graphene Electrosensor

This paper describes the development of a "diffusion-to-surface" ratiometric graphene electrosensor for the selective detection of live cells and pathogens that highly express mannose-binding proteins (MBPs). MBPs have been implicated in many pathological processes and are identified on specific types of bacteria. Consequently, MBPs are a promising biomarker for targeted disease diagnosis and therapy. Here, we develop a unique electrosensor that features a ratiometric voltammetric signal for the selective probing of MBPs. Self-assembly of mannosyl anthraquinone (AQ) to a graphene oxide-decorated screen-printed electrode produces the sensor with an inherent surface-controlled voltammetric signal. Subsequently, addition of a redox probe (RP) imparts the system with a diffusion-controlled current, thus enabling a ratiometric sensing rationale for which AQ serves as a reference. While the reference current is hardly compromised by adding analytes, RP exhibits a concentration-dependent current quenching on addition of mannose-selective lectins over other proteins. Importantly, this ratiometric electrosensor has proven to be applicable for the ratiometric probing of alternatively activated macrophages and a Gram-negative bacterium highly expressing MBPs, but shows minimal response to a series of control live cells and bacteria without mannose receptor expression.

Irreversible destruction of amyloid fibril plaques by conjugated polymer based fluorogenic nanogrenades

Supramolecular assembly between conjugated polymers and fluorescent dyes produces a unique class of fluorogenic "nanogrenades". These nanomaterials have shown the ability to image as well as irreversibly destruct amyloid β fibril plaques by simple light irradiation.

Interlocked supramolecular glycoconjugated polymers for receptor-targeting theranostics

We report an interlocked supramolecular ensemble formed between a conjugated polymer (CP) and a fluorescent glycoprobe for receptor-targeting cancer cell theranostics.

Fabrication and multifunctional properties of ultrasmall water-soluble tungsten oxide quantum dots

Novel ultrasmall water-soluble tungsten oxide quantum dots with multifunctional properties have been successfully developed by a facile and green method.

Construction of biomolecular sensors based on quantum dots

At this post-genomic era, the focus of life science research has shifted from life genetic information to general biofunctions. Biomolecular sensors based on QDs will play an important role in the identification and detection of biomolecules.

Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide

2D MoS₂ enhances the receptor-targeting cell and tissue imaging ability of a fluorophore-labeled ligand in a concentration-dependent manner.