Alkali Ion-Accelerated Gelation of MXene-Based Conductive Hydrogel for Flexible Sensing and Machine Learning-Assisted Recognition.

Conductive hydrogels are promising active materials for wearable flexible electronics, yet it is still challenging to fabricate conductive hydrogels with good environmental stability and electrical properties. In this work, a conductive MXene/LiCl/poly(sulfobetaine methacrylate) hydrogel system was successfully prepared with an impressive conductivity of 12.2 S/m.

Planar-structured thiadiazoloquinoxaline-based NIR-II dye for tumor phototheranostics.

Second near-infrared (NIR-II) fluorescence imaging shows huge application prospects in clinical disease diagnosis and surgical navigation, while it is still a big challenge to exploit high performance NIR-II dyes with long-wavelength absorption and high fluorescence quantum yield. Herein, based on planar π-conjugated donor-acceptor-donor systems, three NIR-II dyes (TP-DBBT, TP-TQ1, and TP-TQ2) were synthesized with bulk steric hindrance, and the influence of acceptor engineering on absorption/emission wavelengths, fluorescence efficiency and photothermal properties was systematically investigated. Compared with TP-DBBT and TP-TQ2, the TP-TQ1 based on 6,7-diphenyl-[1,2,5]thiadiazoloquinoxaline can well balance absorption/emission wavelengths, NIR-II fluorescence brightness and photothermal effects.

Sulfone/Carbonyl-Based Donor-Acceptor Fluorescent Dyes: Synthesis, Structures, Photophysical Properties and Cell Imaging.

Electron-accepting units play vital roles in constructing donor-acceptor (D-A) conjugated organic optoelectronic materials; the electronic structures and functions of the acceptors need to be carefully unveiled to controllably tailor the optoelectronic properties. We have synthesized two D-A conjugated organic fluorophores, TPA-SO and TPA-CO, with similar molecular skeletons based on sulfone- or carbonyl-containing polycyclic aromatic acceptors. Both TPA-SO and TPA-CO display obvious solvent polarity-dependent photophysical properties and large Stokes shift of over 100 nm for strong intramolecular charge transfer processes.

Heterojunction MnO-nanosheet-decorated Ag nanowires with enhanced oxidase-like activity for the sensitive dual-mode detection of glutathione.

The biocatalytic design of nanomaterials with enzyme-like activity is considered a reliable and promising toolkit for the generation of diagnostic agents in complex biological microenvironments. However, the preparation of nanomaterials while maintaining a high catalytic activity in tumor cells (pH 6.0-6.

Biodegradable Charge-Transfer Complexes for Glutathione Depletion Induced Ferroptosis and NIR-II Photoacoustic Imaging Guided Cancer Photothermal Therapy.

Suffering from the laborious synthesis and undesirable tumor microenvironment response, the exploitation of novel NIR-II absorbing organic photothermal agents is of importance to promote phototherapeutic efficacy. Herein, two kinds of charge-transfer complex nanoparticles (TMB-F4TCNQ and TMB-TCNQ) are prepared by supramolecular assembly. Because of the larger energy gap between donor and acceptor, TMB-F4TCNQ presents higher charge-transfer degree (72 %) than that of TMB-TCNQ (48 %) in nanoaggregates.

A dual-mode resonance Rayleigh scattering and colorimetric alkaline phosphatase assay based on ascorbic acid-induced signal generation from manganese dioxide nanosheets.

Multimode sensing has attracted extensive attention because they provide more than one transduction channel, thus improving accuracy and sensitivity. Due to the structural diversity, MnO nanosheets and nanoneedles were successively obtained one-step redox reaction and different self-assembly methods. MnO nanosheets possess outstanding optical properties including extremely strong resonance Rayleigh scattering (RRS) and absorbance signal, and were selected as a dual-mode sensing material.

Biomimetic theranostic strategy for anti-metastasis therapy of breast cancer via the macrophage membrane camouflaged superparticles.

The rational design of theranostic systems are critical for addressing challenging issues associated with cancers. Toward this objective, the multifunctional biomimetic superparticle, termed as DOX-QDs-Lip@M, which can specifically deliver drug to tumor and synergistically monitor their therapeutic effects, was fabricated. Initially, anticancer drug doxorubicin hydrochloride (DOX) and imaging agent quaternary quantum dots (QDs) were loaded into the hydrophilic core region and hydrophobic chamber of liposome by self-assembly method, respectively.

Inorganic Nanozyme with Combined Self-Oxygenation/Degradable Capabilities for Sensitized Cancer Immunochemotherapy.

Recently emerged cancer immunochemotherapy has provided enormous new possibilities to replace traditional chemotherapy in fighting tumor. However, the treatment efficacy is hampered by tumor hypoxia-induced immunosuppression in tumor microenvironment (TME). Herein, we fabricated a self-oxygenation/degradable inorganic nanozyme with a core-shell structure to relieve tumor hypoxia in cancer immunochemotherapy.

A novel fluorescence "turn off-on" nanosensor for sensitivity detection acid phosphatase and inhibitor based on glutathione-functionalized graphene quantum dots.

In this paper, we developed a label-free and sensitive fluorescence sensor for acid phosphatase (ACP) and its inhibitor parathion-methyl (PM) detection based on glutathione-functionalized graphene quantum dots (GQDs@GSH). Upon addition of MnO nanosheets, the fluorescence of GQDs@GSH could be efficiently quenched via a fluorescence resonance energy transfer. ACP could easily catalyze the hydrolysis of L-Ascorbic acid-2-phosphate (AAP) to ascorbic acid (AA), which could reduce MnO nanosheets to Mn in acidic environment, leading to dramatically increase of the fluorescence intensity of GQDs@GSH.

A novel fluorimetric sensing strategy for highly sensitive detection of phytic acid and hydrogen peroxide.

In this paper, we developed a sensitive sensor for phytic acid (PA) and hydrogen peroxide (HO) detection based on glutathione-functionalized graphene quantum dots (GQDs@GSH). The fluorescence of GQDs@GSH was found to be effectively quenched by Fe ions via photo-induced electron transfer (PET) process. Upon the addition of PA to GQDs@GSH/Fe system, the fluorescence of GQDs@GSH was significantly restored due to the strong chelating and reducing ability of PA, Fe ions could be reduced to Fe ions by PA and formed PA/Fe complex.

A novel label-free fluorescent sensor for highly sensitive detection of bleomycin based on nitrogen-doped graphene quantum dots.

In this work, we presented a novel label-free biosensor for rapid detection of bleomycinsulphate (BLM). The biosensor was based on the fluorescent "turn off-on" of nitrogen-doped graphene quantum dots (N-GQDs), which was prepared in a green way from citric acid and ammonia. The richness of carboxyl groups on the N-GQDs enabled strong adsorption of ssDNA to the surface of N-GQDs through π-π stacking interactions, resulting in the effective fluorescence quenching of N-GQDs system.

A novel fluorescence biosensor for sensitivity detection of tyrosinase and acid phosphatase based on nitrogen-doped graphene quantum dots.

In this paper, we developed a sensitive fluorescence biosensor for tyrosinase (TYR) and acid phosphatase (ACP) activity detection based on nitrogen-doped graphene quantum dots (N-GQDs). Tyrosine could be catalyzed by TYR to generate dopaquinone, which could efficiently quench the fluorescence of N-GQDs, and the degree of fluorescence quenching of N-GQDs was proportional to the concentration of TYR. In the presence of ACP, l-Ascorbic acid-2-phosphate (AAP) was hydrolyzed to generate ascorbic acid (AA), and dopaquinone was reduced to l-dopa, resulting in the fluorescence recovery of the quenched fluorescence by dopaquinone.

Fluorescence turn-off-on probe based on polypyrrole/graphene quantum composites for selective and sensitive detection of paracetamol and ascorbic acid.

In this work, we presented a novel biosensor for rapid detection of paracetamol and ascorbic acid. The novel biosensor was based on the fluorescent "turn off-on" of polypyrrole/graphene quantum dots (PPy/GQDs) composites. The composites exhibit strong fluorescence emission, which is dramatically enhanced as high as three times than that of pure GQDs.

A novel turn-on fluorescent strategy for sensing ascorbic acid using graphene quantum dots as fluorescent probe.

In this paper, a facile and rapid fluorescence turn-on assay for fluorescent detection of ascorbic acid (AA) was developed by using the orange emission graphene quantum dots (GQDs). In the presence of horse radish peroxidase (HRP) and hydrogen peroxide (HO), catechol can be oxidized by hydroxyl radicals and converted to o-benzoquinone, which can significantly quench the fluorescence of GQDs. However, when AA present in the system, it can consume part of HO and hydroxyl radicals to inhibit the generation of o-benzoquinone, resulting in fluorescence recovery.

Sensitive fluorescence detection of ATP based on host-guest recognition between near-infrared β-Cyclodextrin-CuInS QDs and aptamer.

We have developed a near-infrared (NIR) fluorescent aptamer-based sensor for sensitive detection of adenosine-5'-triphosphate (ATP) by using a ATP-binding aptamer and β-Cyclodextrin-CuInS quantum dots (β-CD-CuInS QDs). The fluorescence of β-CD-CuInS QDs has a slight enhancement with the addition of ATP-binding aptamer due to the host-guest recognition between aptamer and β-CD. When ATP is added, it will bind to aptamer to form G-quadruplexes.

Highly sensitive detection of acid phosphatase by using a graphene quantum dots-based förster resonance energy transfer.

A novel and effective fluorescence strategy was developed for sensitive and selective detection of acid phosphatase (ACP). A förster resonance energy transfer (FRET) biosensor was established by attaching nile red (NR) to graphene quantum dots (GQDs) via lecithin/β-Cyclodextrin (lecithin/β-CD) complex as the linker. The introduction of lecithin/β-CD would brought GQDs-NR pair close enough through both electrostatic interaction and hydrophobic interaction, thereby making the FRET occur and thus resulting in the fluorescence quenching of GQDs (donor) and meanwhile the fluorescence enhancement of NR (acceptor).

Sensitive detection of acid phosphatase based on graphene quantum dots nanoassembly.

In this study, we report a convenient label-free fluorescence biosensor for the detection of acid phosphatase based on the aggregation-caused quenching of graphene quantum dots (GQDs). The fluorescence of GQDs could be quenched by poly-(dimethyl diallyl ammonium chloride) (PDDA); the high efficiency of the quenching was caused by the non-covalent binding of positively charged PDDA to negatively charged GQDs through electrostatic interactions, aggregating to form a GQDs-PDDA complex. Addition of sodium hexametaphosphate (NaPO3)6 could effectively turn on the quenched fluorescence due to the stronger electrostatic interactions between positively charged PDDA and negatively charged (NaPO3)6.

Graphene quantum dots as selective fluorescence sensor for the detection of ascorbic acid and acid phosphatase via Cr(vi)/Cr(iii)-modulated redox reaction.

A facile and rapid fluorescence assay based on a redox reaction for successively detecting ascorbic acid and acid phosphatase was developed via Cr(vi)-modulated graphene quantum dots (GQDs). Graphene quantum dots with yellow-green emission were first synthesized via a one-pot hydrothermal method. Based on the electrostatic adsorption of Cr on GQDs and the strong chelation between Cr and the -COOH and -OH groups on the surface of GQDs, the fluorescence of GQDs could be greatly quenched by Cr ions.

Label-free aptamer biosensor for selective detection of thrombin.

We fabricated a novel fluorescence biosensor for the selective detection of thrombin by using bovine serum albumin-capped CdS quantum dots (BSA-CdS QDs). Two kinds of designed DNA (DNA1 and DNA2) could bind to CdS QDs through the electrostatic interaction between DNA and Cd(2+) on the surface of CdS QDs. The obtained DNA/BSA-CdS QDs kept stable in the solution with the fluorescence intensity obviously enhanced.

Ultrasensitive detection of amifostine and alkaline phosphatase based on the growth of CdS quantum dots.

In this study, we reported a simple and sensitive fluorescence nanosensor for rapid detection of amifostine and alkaline phosphatase (ALP). The novel nanosensor was based on the fluorescence "turn on-off" of CdS quantum dots (QDs). Firstly, Cd(2+) cation could react with S(2-) anion to generate fluorescent CdS QDs in the presence of amifostine.

Fluorescence detection of adenosine-5'-triphosphate and alkaline phosphatase based on the generation of CdS quantum dots.

We have developed an analytical method to detect adenosine-5'-triphosphate (ATP) and alkaline phosphatase (ALP) based on the generation of CdS quantum dots (QDs). We demonstrated that Cd(2+) cation reacts with S(2-) anion to generate fluorescent CdS QDs in the presence of some certain amount of ATP. With increase in the ATP concentration, the fluorescence intensity of CdS QDs was also enhanced.

A label-free fluorescence detection strategy for lysozyme assay using CuInS₂ quantum dots.

We have developed a simple and efficient fluorescence detection system for lysozyme utilizing I-III-VI type Cu-In-S ternary quantum dots (CuInS2 QDs) as the probe. Water-soluble near-infrared CuInS2 QDs capped with 3-mercaptopropionic acid were directly synthesized by using a hydrothermal method. Poly(dimethyl diallyl ammonium chloride), as a cationic polyelectrolyte, could bind to 3-mercaptopropionic acid-capped CuInS2 QDs via electrostatic interactions that would lead to fluorescence quenching of CuInS2 QDs.

Fluorescence detection of Pb(2+) based on the DNA sequence functionalized CdS quantum dots.

In this paper, we have developed a simple and rapid method for the detection of Pb(2+) based on the DNA sequence capped CdS quantum dots (QDs). We utilized the designed guanine (G)-rich DNA sequence (PS2.M) as a coating reagent to synthesize the DNA-capped CdS QDs.

Near-infrared fluorescence probe for the determination of alkaline phosphatase.

Water-soluble CuInS2 quantum dots (QDs) were directly synthesized in an aqueous solution with mercaptopropionic acid (MPA) as stabilizers, and were functionalized using tryptophan molecules to form tryptophan-functionalized CuInS2 QDs (W-CuInS2 QDs) that had a strong fluorescence emission around 689 nm. The fluorescence of W-CuInS2 QDs could be quenched by Cu(2+) and then the addition of pyrophosphate (PPi) could effectively turn on the quenched fluorescence due to the strong interaction between Cu(2+) and PPi. The alkaline phosphatase (ALP) could catalyze the hydrolysis of PPi that would disassemble the complex of PPi-Cu(2+)-PPi.