DNA Gate-Based CRISPR-Cas Exponential Amplification System for Ultrasensitive Small Extracellular Vesicle Detection to Enhance Breast Cancer Diagnosis

Tumor-derived small extracellular vesicles (tEVs) as potential biomarkers possess abundant surface proteins closely related to parent cells, which are crucial for noninvasive cancer diagnosis. However, tEVs exhibit phenotype heterogeneity and low abundance, posing a significant challenge for multiplex detection with a high sensitivity. Herein, we developed a DNA gate-based exponential amplification CRISPR-Cas (DGEAC) system for accurate and ultrasensitive detection of tEVs, which can greatly improve the accuracy of breast cancer (BC) diagnosis. Based on the coexpression of CD63 and vascular endothelial growth factor (VEGF) on BC-derived tEVs, we developed a dual-aptamer-based AND gate fluorescent probe by proximity hybridization. By integrating the target recognition and trans-cleavage activity of Cas12a, an autocatalysis-driven exponential amplification circuit was developed for ultrasensitive detection of CD63 and VEGF proteins on tEVs, which could avoid false negative signals from single protein or other interfering proteins. We achieved highly sensitive detection of tEVs over a linear range from 1.75 × 103 to 3.5 × 108 particles/mL with a detection limit as low as 1.02 × 103 particles/mL. Furthermore, the DGEAC system can distinguish tEVs from tEVs derived from different BC cell lines, including MDA-MB-231, MCF-7, SKBR3, and MCF-10A. Compared to linear amplification (AUC 90.0%), the DGEAC system effectively differentiates BC in different stages (AUC 98.3%).

Ultrasensitive determination of surface proteins on tumor-derived small extracellular vesicles for breast cancer identification based on lanthanide-activated signal amplification strategy

Small extracellular vesicles (sEVs) carrying multiple tumor-associated proteins inherited from parental cells play crucial roles in noninvasive breast cancer (BC) diagnosis. However, it is challenging to assess the subtle variations of surface proteins on sEV membranes due to the highly heterogeneous BC. Therefore, a simple and ultrasensitive assay based on lanthanide (Ln3+)-activated luminescence signal amplification was developed to detect multiple surface proteins on BC-derived sEVs. Multiple protein biomarkers on sEVs can be well identified with high sensitivity and specificity through dissolution-amplified luminescence of the NaEuF4 nanoparticle-based nanoprobe. We employ linear discriminant analysis to successfully discriminate triple negative BC cell (MDA-MB-231 cell) derived sEVs from other breast cell lines (MCF-7, SK-BR-3, BT474 and MCF-10A cell). Furthermore, the strategy enables high accuracy for districting the progression stages of BC patients and healthy donors. The simple and sensitive signal amplification strategy exhibits great potential for early clinic diagnosis by precise protein profiling of sEVs.

An erythrocyte membrane-camouflaged fluorescent covalent organic framework for starving/nitric oxide/immunotherapy of triple-negative breast cancer

It is a great challenge to effectively treat triple-negative breast cancer (TNBC) due to lack of therapeutic targets and drug resistance of systemic chemotherapy. Rational design of nanomedicine with good hemocompatibility is urgently desirable for combination therapy of TNBC. Herein, an erythrocyte membrane-camouflaged fluorescent covalent organic framework (COF) loaded with an NO donor (hydroxyurea, Hu), glucose oxidase (GOx) and cytosine-phosphate-guanine oligonucleotides (CPG) (COF@HGC) was developed for imaging-guided starving/nitric oxide (NO)/immunization synergistic treatment of TNBC. The substances of HGC are easily co-loaded onto the COF due to the ordered pore structure and large surface area. And a folic acid-modified erythrocyte membrane (FEM) is coated on the surface of COF@HGC to improve targeted therapy and haemocompatibility. When COF@HGC@FEM is internalized into tumor cells, hemoglobin (Hb) on FEM and GOx loaded on the COF can trigger cascade reactions to kill tumor cells due to the simultaneous production of NO and exhaustion of glucose. Meanwhile, the COF with excellent fluorescence properties can be used as a self-reporter for bioimaging. Furthermore, the CPG can reprogram tumor-associated macrophages from tumor-supportive phenotype to anti-tumor phenotype and enhance immunotherapy. Through the "three-in-one" strategy, the biomimetic nanoplatform can effectively inhibit tumor growth and reprogram the tumor immunosuppression microenvironment in the TNBC mouse model.

A near-infrared light-activated nanoprobe for simultaneous detection of hydrogen polysulfide and sulfur dioxide in myocardial ischemia-reperfusion injury

Ischemia-reperfusion-induced cardiomyocyte mortality constitutes a prominent contributor to global morbidity and mortality. However, early diagnosis and preventive treatment of cardiac I/R injury remains a challenge. Given the close relationship between ferroptosis and I/R injury, monitoring their pathological processes holds promise for advancing early diagnosis and treatment of the disease. Herein, we report a near-infrared (NIR) light-activated dual-responsive nanoprobe (UCNP@mSiO2@SP-NP-NAP) for controllable detection of hydrogen polysulfide (H2Sn) and sulfur dioxide (SO2) during ferroptosis-related myocardial I/R injury. The nanoprobe's responsive sites could be activated by NIR and Vis light modulation, reversibly alternating for at least 5 cycles. We employed the nanoprobe to monitor the fluctuation levels of H2Sn and SO2 in H9C2 cardiomyocytes and mice, revealing that H2Sn and SO2 levels were up-regulated during I/R. The NIR light-activated dual-responsive nanoprobe could be a powerful tool for myocardial I/R injury diagnosis. Moreover, we also found that inhibiting the initiation of the ferroptosis process contributed to attenuating cardiac I/R injury, which indicated great potential for treating I/R injury.

Dye-sensitized rare-earth-doped nanoprobe for simultaneously enhanced NIR-II imaging and precise treatment of bacterial infection

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for causing life-threatening infections that result in high morbidity and mortality rates. The development of advanced imaging and therapeutic methods for in vivo diagnosis and treatment of MRSA infections remains challenging. Here, we develop a hybrid nanoplatform based on rare-earth-doped nanoparticles (RENPs) sensitized by a moiety-engineered near-infrared (NIR) TPEO-820 dye and with a ZIF-8 layer that incorporates CysNO, a photochemically triggered nitric oxide donor. We then use the hybrid for both NIR-II bioimaging and photoactivatable treatment of MRSA-infected wounds. We show that the NIR dye sensitization leads to an 8.5-fold enhancement of the downshifting emission and facilitates deep-tissue NIR-II imaging of bacterial infections. Moreover, the sensitization strategy enhances the UV emission of RENPs by two orders of magnitude, leading to the efficiently controllable release of nitric oxide for effective disinfection of MRSA in vitro and in vivo. The hybrid nanoplatform thus offers promising opportunities for simultaneous localization and controllable treatment of MRSA. STATEMENT OF SIGNIFICANCE: Early detection and treatment of MRSA infections are crucial for reducing public health risks. It is a significant challenge that develops sensitive in vivo diagnosis and complete elimination of drug-resistant bacterial infections. Herein, a nanoplatform has been developed for photoactivatable therapy of MRSA infections and deep tissue NIR-II imaging. This platform utilizes lanthanide-doped rare earth nanoparticles (RENPs) that are sensitized by a moiety-engineered near-infrared (NIR) dye TPEO-820. The TPEO-820 sensitized RENPs exhibit 5 times increase in the release of NO concentration for MRSA treatment compared to unsensitized RENPs, enabling precise therapy of MRSA infection both in vitro and in vivo. Moreover, the platform demonstrates NIR-II luminescence in vivo, allowing for sensitive imaging in deep tissue for MRSA infection.

Polymerase-Driven Logic Signal Amplification for the Detection of Small Extracellular Vesicle Surface Proteins and the Identification of Breast Cancer

Small extracellular vesicles (sEVs) derived from tumors contain a vast amount of cellular information and are regarded as a potential diagnostic biomarker for noninvasive cancer diagnosis. Nevertheless, it remains challenging to accurately measure sEVs from clinical samples due to the low abundance of these vesicles as well as their phenotypic heterogeneity. Herein, a polymerase-driven logic signal amplification system (PLSAS) was developed for the high-sensitivity detection of sEV surface proteins and breast cancer (BC) identification. Aptamers were introduced to serve as sensing modules to specifically recognize target proteins. By changing the input DNA sequences, two polymerase-driven primer exchange reaction systems were rationally designed for DNA logic computing. This allows for autonomous targeting of a limited number of targets using "OR" and "AND" logic, leading to a significant increase in fluorescence signals and enabling the specific and ultrasensitive detection of sEV surface proteins. In this work, we investigated surface proteins of mucin 1 (MUC1) and the epithelial cell adhesion molecule (EpCAM) as model proteins. When MUC1 or EpCAM proteins were used as single signal input in the "OR" DNA logic system, the detection limit of sEVs was 24 or 58 particles/μL, respectively. And MUC1 and EpCAM proteins of sEVs can be simultaneously detected in the AND logic method, which can significantly reduce the effect of phenotypic heterogeneity of sEVs to distinguish the source of sEVs derived from various mammary cell lines, such as MCF-7, MDA MB 231, SKBR3, and MCF-10A. The approach has achieved high discrimination in serologically tested positive BC samples (AUC 98.1%) and holds significant potential in advancing the early diagnosis and prognostic assessments of BC.

Nucleic acid and nanomaterial-assisted signal-amplified strategies in fluorescent analysis of circulating tumor cells and small extracellular vesicles

As two main types of liquid biopsy markers, both circulating tumor cells (CTCs) and small extracellular vesicles (sEVs) play important roles in the diagnosis and prognosis of cancers. CTCs are malignant cells that detach from the original tumor tissue and enter the circulation of body fluids. sEVs are nanoscale vesicles secreted by normal cells or pathological cells. However, CTCs and sEVs in body fluids are scarce, leading to great difficulties in the accurate analysis of related diseases. For the sensitive detection of CTCs and sEVs in body fluids, various types of nucleic acid and nanomaterial-assisted signal amplification strategies have been developed. In this review, we summarize the recent advances in fluorescent detection of CTCs and sEVs in liquid biopsy based on nucleic acid and nanomaterial-assisted signal amplification strategies. We also discuss their advantages, challenges, and future prospects.

Endogenous stimulus-controlled estradiol@AIEgen-based covalent organic framework for the reduction of myocardial ischemia/reperfusion injury

An ATP stimuli-responsive tetrahedra DNA-gated fluorescent covalent organic frameworks (COFs) were developed for estradiol (E2) delivery and controllable realese. The fluorescent COFs with efficent E2 loading showed great potential against...

Cell-Membrane-Anchored Upconversion Nanoprobe for Near-Infrared Light Triggered Cell-Cell Interactions

Manipulating cell-cell interactions is of great significance in cell communication and cell-based therapies. Although efforts have been made to construct cell-cell assembly by stimuli-responsive host-guest interactions, controllable cell-cell interactions by near-infrared (NIR) light triggered reversible assembly remain a challenge. Herein, we develop a NIR-controlled system based on β-cyclodextrin (β-CD) modified upconversion nanoparticles (UCNPs) for reversible and noninvasive manipulation of cell assembly and disassembly, which is realized by host-guest interactions between E/Z-photoisomerization of arylazopyrazole (AAP) and β-CD under the NIR irradiation. UCNPs can convert NIR to ultraviolet light, which leads to the transformation of AAP from the E-isomer to the Z-isomer. And it can be reverted back to the E-isomer under visible light irradiation. This reversible photoisomerization can modulate the host-guest interaction between β-CD and AAP, thus leading to reversible cell assembly and disassembly. Furthermore, by precise regulating cell-cell interactions by NIR light, cell-cell communication and molecular transportation can be realized. Given the diversity of host and guest molecules and the advantages of NIR light in biological applications, reversible cell-cell assembly has great potential for the regulation of cell behaviors and cell-based therapies.

Ratiometrically pH-Insensitive Upconversion Nanoprobe: Toward Simultaneously Quantifying Organellar Calcium and Chloride and Understanding the Interaction of the Two Ions in Lysosome Function

Calcium and chloride levels are closely related to lysosome dysfunction. However, the simultaneous measurement of calcium (Ca²⁺) and chloride (Cl^-) in acidic subcellular organelles, which is conducive to a deep understanding of lysosome-related biological events, remains a challenge. In this study, we developed a pH-insensitive, ratiometric NIR nanoprobe for the simultaneous detection of Ca²⁺ and Cl^- in acidic lysosomes and determined the roles of the two ions in lysosome function. The upconversion nanoprobe with blue, green, and red emissions was modified with a Ca²⁺-sensitive dye (Rhod-5N) and Cl^--responsive fluorophore (10,10'-bis[3-carboxypropyl]-9,9'-biacridinium dinitrate, BAC). As a result of a dual-luminescence resonance energy transfer between upconversion nanoparticles (UCNPs) and Rhod-5N/BAC, the blue and green upconversion luminescence (UCL) of UCNPs were quenched and the red UCL was used as the reference signal. The ratiometric upconversion nanoprobe possesses a specific ability for the concurrent recognition of Ca²⁺ and Cl^- ions independent of the influence of the environmental pH. To locate the probe in the lysosome, dextran was further modified with upconversion nanoparticles. Then, the nanoprobe with a high spatial resolution was constructed for the simultaneous monitoring of Ca²⁺ and Cl^- in acidic lysosomes. Moreover, it was found that the reduction of lysosomal Cl^- affects the release of lysosomal Ca²⁺, which further blocks the activities of specific lysosomal enzymes. The ratiometric NIR nanoprobe has great potential for decoding and evaluating lysosomal diseases.

Designed synthesis of an sp2 carbon-conjugated fluorescent covalent organic framework for selective detection of Fe3

A new fully conjugated covalent organic framework material (COF_TFPPy-ThDAN) has been synthesized via the Knoevenagel condensation reaction using 1,3,6,8-tetra(4-formylphenyl)pyrene (TFPPy) as the chromogenic unit and 2,2'-([2,2'-bithiophene]-5,5'-diyl)diacetonitrile (ThDAN) as the linker. The COF_TFPPy-ThDAN has been successfully prepared under the optimized conditions and showed excellent crystallinity and chemical stability. Especially, it was able to maintain its crystallinity even when immersed under harsh conditions such as HCl (3 M) and NaOH (3 M). Meanwhile, COF_TFPPy-ThDAN exhibited good fluorescence properties, which could remain relatively stable under different pH conditions. Moreover, COF_TFPPy-ThDAN was further employed for the detection of Fe³⁺ with high sensitivity and selectivity with a limit of detection (LOD) of 1.26 μM. COF_TFPPy-ThDAN with high stability and fluorescence is a promising material for chemical sensing.

Ultrasensitive detection of tumor-derived small extracellular vesicles based on nonlinear hybridization chain reaction fluorescence signal amplification and immunomagnetic separation

An ultrasensitive nonlinear hybridization chain reaction signal amplification fluorescence assay for the detection of small extracellular vesicles.

Rational Synthesis of Imine-Linked Fluorescent Covalent Organic Frameworks with Different pKa for pH Sensing In Vitro and In Vivo

Precise modulation of pH in living cells plays a vital role in the study of many diseases, such as cancer and rheumatoid arthritis. Here, a series of imine-linked covalent organic frameworks (COFs) were rationally designed and developed for pH sensing in tumor cells and zebrafish. Four monomers were chosen to synthesize COFs (COF₁-COF₄) with different pK_a by a simple orthogonal combination through condensation reaction. The as-obtained COFs exhibited a sensitive pH-dependent fluorescence response compared to their building blocks. Among them, COF₂ possessed a high crystallinity, excellent fluorescence, and suitable pK_a for biosensing. For bioimaging applications, COF₂ was modified with poly-d-lysine (PDL) to improve its biocompatibility and endocytosis efficiency. After that, PDL-modified COF₂ (PDL@COF₂) was used as a novel fluorescence probe with a superior linear pH response over the range from 5.0 to 8.0 due to its fully reversible protonation and deprotonation. The fluorescent PDL@COF₂ was further employed as a good candidate for pH imaging in tumor cells and zebrafish. The as-constructed environment-sensitive fluorescent COFs have greatly expanded the applications of COFs in the biological area.

Near-Infrared Light Controllable DNA Walker Driven by Endogenous Adenosine Triphosphate for in Situ Spatiotemporal Imaging of Intracellular MicroRNA

As a powerful signal amplification tool, the DNA walker has been widely applied to detect rare microRNA (miRNA) in vivo. Despite the significant advances, a near-infrared (NIR) light controllable DNA walker for signal amplification powered by an endogenous initiator has not been realized, which is crucial for spatiotemporal imaging of miRNA in living cells with high sensitivity. Herein, we constructed a NIR-photoactivatable DNA walker system, which was powered by endogenous adenosine triphosphate (ATP) for in situ miRNA imaging with spatial and temporal resolution. The system was very stable with an extremely low fluorescent background for the bioimaging in living cells. We employed upconversion nanoparticles (UCNPs) as the carriers of the DNA probe and transducers of converting NIR to UV light. Coupled with the DNA walker fueled by intracellular ATP, a smart system based on the NIR light initiated DNA walker was successfully developed for precise spatiotemporal control in living cells. Triggered by NIR light, the DNA walker could autonomously and progressively travel along the track with the assistance of intracellular ATP. The system has been successfully applied for in situ miRNA imaging in different cell lines with highly spatial and temporal resolution. This strategy can expand NIR photocontrol the DNA walker for precise imaging in a biological system.

pH-Sensitive Dye-Based Nanobioplatform for Colorimetric Detection of Heterogeneous Circulating Tumor Cells

The efficient capture and sensitive detection of circulating tumor cells (CTCs) play a vital role in cancer diagnosis and prognosis. However, CTCs in the peripheral blood are very rare and heterogeneous, which make them difficult to isolate and detect. Herein, a novel colorimetric nanobioplatform was successfully developed for the highly efficient capture and highly sensitive detection of heterogeneous CTCs, which consisted of two parts: the multivalent aptamer-modified gold nanoparticles as the capture unit and two kinds of aptamer-functionalized pH-sensitive allochroic dyes (thymolphthalein and curcumin) @ molybdenum disulfide nanoflakes (MoS₂ NFs) acting as the visual simultaneous detection of heterogeneous CTCs. Using MCF-7 and HeLa cells as the CTC models, the capture unit can effectively isolate the CTCs due to the multivalent probe with improved affinity. The two allochroic dyes can display obvious color changes under alkaline conditions (pH 12.5) in the presence of MCF-7 and HeLa cells, which provided a rapid and sensitive strategy for visualizing simultaneous detection of heterogeneous CTCs as low as 5 cells mL^-1. This nanoplatform possessed a high sensitivity toward CTC detection owing to high dye loading capacity of MoS₂ NFs and allochroic dyes with excellent pH sensitivity. It can successfully distinguish and quantitatively detect the targeted heterogeneous CTCs from numerous interfering cells in diluted whole blood. It can also be used to detect CTCs from lysed blood samples from cancer patients, indicating promising application for cancer diagnosis.

Near-Infrared Light-Switched MoS2 Nanoflakes@Gelatin Bioplatform for Capture, Detection, and Nondestructive Release of Circulating Tumor Cells

The integrative bioplatform for capture, detection and release of circulating tumor cells (CTCs) is of great significance in clinical diagnosis and biomedical research. To fulfill this demand, we introduced a near-infrared (NIR) light-switched bioplatform for efficient isolation and downstream analysis of CTCs. The platform was created by first modifying the PEG-MoS₂ nanoflakes (NFs)@gelatin nanocomposite on the ITO surface, and then introducing the MUC1 aptamer as a specific recognition element via coupling reaction between aptamer and gelatin to achieve the specific capture for CTCs. Subsequently, the captured cells are released under a NIR light irradiation (808 nm) by using MoS₂ NFs as the NIR-regulated control element. Significantly, this platform could capture and release of CTCs with an excellent capture/release efficiency of 89.5% and 92.5%, respectively. Furthermore, the electrochemical bioplatform exhibited a wide linear range for the detection of CTCs from 50 to 1 × 10⁶ cells mL^-1 with a detection limit of 15 cells mL^-1. After 5 days of reculture, the released cells still maintain good cell shape and proliferation capacity. Moreover, the bioplatfrom is a simple, versatile, and universal system for the recognition, capture, release, and detection of different types of CTCs. Therefore, this bioplatform shows potential applications on the early diagnosis of cancers.

A ratiometric fluorescent assay for the detection and bioimaging of alkaline phosphatase based on near infrared Ag2S quantum dots and calcein

Herein, a ratiometric fluorescent method was developed for alkaline phosphatase (ALP) detection based on near-infrared (NIR) Ag₂S quantum dots (QDs) and calcein through the competitive approach. The system based on Ag₂S QDs and calcein shows green (maximum emission at 512 nm from calcein) and near infrared (NIR) fluorescence (maximum 798 nm from Ag₂S QDs) under the same excitation wavelength (468 nm). In the presence of Ce³⁺, the fluorescence intensity of calcein is decreased due to static quenching, while the fluorescence intensity of Ag₂S QDs is enhanced through aggregation induced emission (AIE). The p-nitrophenyl phosphate is hydrolyzed by ALP, and the yield phosphate ions bind with Ce³⁺ with higher affinity than these of Ag₂S QDs and calcein. Therefore, the green fluorescence from calcein is recovered while NIR fluorescence from Ag₂S QDs is decreased. On the basis of these findings, a ratiometric fluorescence assay was developed for the measurement of ALP activity. The ratio of fluorescence intensity at 512 and 798 nm (F₅₁₂/F₇₉₈) was well associated with the ALP concentration ranging from 2 to 100 mU/mL with the detection limit of 1.28 mU/mL. The method was successfully applied for detecting ALP in human serum with an acceptable recovery and bioimaging intracellular ALP with good performance. In addition, the approach was also employed for the screening ALP inhibitor.

Topological magnon insulator with a Kekulé bond modulation

We examine the combined effects of a Kekulé coupling texture (KC) and a Dzyaloshinskii-Moriya interaction (DMI) in a two-dimensional ferromagnetic honeycomb lattice. By analyzing the gap closing conditions and the inversions of the bulk bands, we identify the parameter range in which the system behaves as a trivial or a nontrivial topological magnon insulator. We find four topological phases in terms of the KC parameter and the DMI strength. We present the bulk-edge correspondence for the magnons in a honeycomb lattice with an armchair or a zigzag boundary. Furthermore, we find Tamm-like edge states due to the intrinsic on-site interactions along the boundary sites. Our results may have significant implications to magnon transport properties in the 2D magnets at low temperatures.

Nanoscaled luminescent terbium metal–organic frameworks for measuring and scavenging reactive oxygen species in living cells

A nanosized Tb-MOF with a boronic acid ligand can be used for the highly sensitive detection and scavenging of ROS in living cells.

Near-Infrared Fluorescent Ag2S Nanodot-Based Signal Amplification for Efficient Detection of Circulating Tumor Cells

The level of circulating tumor cells (CTCs) plays a critical role in tumor metastasis and personalized therapy, but it is challenging for highly efficient capture and detection of CTCs because of the extremely low concentration in peripheral blood. Herein, we report near-infrared fluorescent Ag₂S nanodot-based signal amplification combing with immune-magnetic spheres (IMNs) for highly efficient magnetic capture and ultrasensitive fluorescence labeling of CTCs. The near-infrared fluorescent Ag₂S nanoprobe has been successfully constructed through hybridization chain reactions using aptamer-modified Ag₂S nanodots, which can extremely improve the imaging sensitivity and reduce background signal of blood samples. Moreover, the antiepithelial-cell-adhesion-molecule (EpCAM) antibody-labeled magnetic nanospheres have been used for highly capture rare tumor cells in whole blood. The near-infrared nanoprobe with signal amplification and IMNs platform exhibits excellent performance in efficient capture and detection of CTCs, which shows great potential in cancer diagnostics and therapeutics.

Role of Autophagy in Ovarian Cryopreservation by Vitrification

BACKGROUND

Ovarian cryopreservation by vitrification and transplantation are useful methods to recover female fertility after radiotherapy and chemotherapy. As type II programmed cell death, autophagy plays important roles in ovarian follicle development, ovarian follicle atresia and anti-stress injury.

OBJECTIVE

The potential role of autophagy in ovarian vitrification was investigated.

MATERIALS AND METHODS

Mouse ovaries were cryopreserved by vitrification, and autophagy was treated, after which the ovarian histology was checked, and ovarian follicles were counted. The apoptotic rate was detected by TUNEL, and apoptotic molecular marker cleaved caspase-3 was checked by immunofluorescence and western blot analysis.

RESULTS

Our results suggested that autophagy was increased in the process of vitrification compared with the fresh ovaries (p<0.05). The number of primordial follicles was decreased through inhibiting or over-activating the autophagy by autophagy inhibitor or activator (p<0.05). However, the number of primary follicles, antral follicles and atretic follicles was not significantly different compared with vitrified/warmed groups. The apoptotic rate was significantly increased in the vitrified/warmed, autophagy-inhibiting and over-activating groups compared with the fresh group (p<0.05), and this result was further confirmed by western blot analysis.

CONCLUSIONS

Taken together, autophagy was activated in the ovarian cryopreservation by vitrification and plays a role in a natural adaptive response to cold stress in ovarian cryopreservation by vitrification.

Transition metal dichalcogenide quantum dots: synthesis, photoluminescence and biological applications

We introduce the synthesis strategy, photoluminescence features and biological applications of TMD QDs.

Platinum Nanoparticle Encapsulated Metal-Organic Frameworks for Colorimetric Measurement and Facile Removal of Mercury(II)

Pt nanoparticle (Pt NP)@UiO-66-NH₂ composites were synthesized and encompassed the benefits of permanent porosity, high thermal and chemical stability of metal-organic frameworks (MOFs), together with the functional behavior of isolated Pt NPs. The PVP-stabilized Pt NPs with the average diameter of 2.48 nm were well dispersed and confined within the framework of UiO-66-NH₂. Pt NPs possess highly peroxidase-like activities and make the composites oxidize 3,3',5,5'-tetramethylbenzidine in the presence of H₂O₂. Moreover, the specific interaction between Hg²⁺ and Pt NPs leads to the effective suppression of the peroxidase-like activity of Pt NP@UiO-66-NH₂, which endows excellent selectivity for Hg²⁺ measurement over the interfering metal ions. Based on the colorimetric sensing system, Hg²⁺ is linearly measured over the range from 0 to 10 nM with a detection limit of 0.35 nM. Moreover, the as-obtained Pt NP@UiO-66-NH₂ nanocomposites exhibit high capacity and good selectivity for Hg²⁺ adsorption, which is successfully applied to treat Hg²⁺ in water with removal efficiency over 99%. With these findings, Pt NP@UiO-66-NH₂ composites can be used to develop a simple and rapid colorimetric sensing system and are utilized as nanoadsorbents for facile removal of Hg²⁺. This work not only expands the scientific researches on MOFs but also provides practical application in environmental, biological, and relative fields.

[Prognosis of the central nervous system involvement in patients with hemophagocytic lymphohistiocytosis]

Objective: To investigate the characteristics and prognostic factor of central nervous system (CNS) involvement in patients with hemophagocytic lymphohistiocytosis (HLH) . Methods: From January 2006 to October 2015, 152 patients with HLH, 88 patients had CNS involvement, their clinical data were collected, and survival was analyzed using the Kaplan-Meier life table method, univariate and multivariate Cox regression model analyses were applied to identify the risk factors of prognosis. Results: ①57.9% patients complicated with neurological symptoms, cerebrospinal fluid abnormalities were observed in 37.0% patients, 57.5% patients had abnormal neuroradiology. ②36 patients survived well, 3 patients lost to follow-up, 49 dead, 1 survival patient had epilepsy. ③The 3-year overall survival rate of 88 patients was 44%. ④abnormal CSF and unreceived IT bore a significant, independent adverse prognostic value (P<0.05) . Conclusion: CNS involvement in HLH has a high frequency and poor prognosis, few patients remained neurologic sequelae; abnormal CSF related to poor prognosis, positive intrathecal injections could improve the prognosis.

Rare earth ions enhanced near infrared fluorescence of Ag2S quantum dots for the detection of fluoride ions in living cells

In this work, a novel phenomenon was discovered that the fluorescence intensity of silver sulfide quantum dots (Ag₂S QDs) could be enhanced in the presence of rare earth ions through aggregation-induced emission (AIE). Based on the strong coordination between rare earth ions and F^-, a facile and label-free strategy was developed for the detection of F^- in living cells. Ag₂S QDs were synthesized using 3-mercaptopropionic acid as sulfur source and stabilizer in aqueous solution. The near infrared (NIR) emitting QDs exhibited excellent photostalilty, high quantum yield and low toxic. Interestingly, the fluorescence intensity of QDs was obviously enhanced upon the addition of various rare earth ions, especially in the presence of Gd³⁺. The AIE mechanism was proved via the TEM, zeta potential and dynamic light scattering analysis. Moreover, the coordination between rare earth ions and F^- could lead to the quenching of fluorescence QDs due to the weakening the AIE. Based on these findings, we developed a highly sensitive and selective method for detection of F^-. The label-free NIR fluorescence probe was successfully used for F^- bioimaging in live cells.

Analytical study of the edge states in the bosonic Haldane model

We investigate the properties of magnon edge states in a ferromagnetic honeycomb spin lattice with a Dzialozinskii-Moriya interaction (DMI). We derive analytical expressions for the energy spectra and wavefunctions of the edge states localized on the boundaries. By introducing an external on-site potential at the outermost sites, we show that the bosonic band structure is similar to that of the fermionic graphene. We investigate the region in the momentum space where the bosonic edge states are well defined and we analyze the width of the edge state and their dependence with the DMI strength. Our findings extend the predictions using topological arguments and they allow size-dependent confirmation from possible experiments.

Black Phosphorus Quantum Dots as the Ratiometric Fluorescence Probe for Trace Mercury Ion Detection Based on Inner Filter Effect

In this work, a novel ratiometric fluorescence sensor has been constructed for the selective and sensitive detection of Hg²⁺, which is based on the inner filter effect (IFE) of tetraphenylporphyrin tetrasulfonic acid (TPPS) toward black phosphorus quantum dots (BP QDs). Highly fluorescent BP QDs were successfully synthesized from bulk BP by sonication-assisted solvothermal method via a top-down route. In the presence of Hg²⁺, the IFE originating from spectral overlap between the excitation of BP QDs and the absorption of TPPS is inhibited and the fluorescence of BP QDs is restored. At the same time, the red fluorescence of TPPS is quenched due to its coordination with Mn²⁺. These phenomena result from the rapid coordination between Mn²⁺ and TPPS in the presence of Hg²⁺, which leads to the dramatic decrease of the absorption of TPPS. On the basis of these findings, we design a ratiometric fluorescence sensor for the detection of Hg²⁺. The as-constructed sensor reveals a good linear response to Hg²⁺ ranging from 1 to 60 nM with a detection limit of 0.39 nM. Furthermore, the sensing assay is applicable to detecting Hg²⁺ in real samples.

Highly Fluorescent Polyimide Covalent Organic Nanosheets as Sensing Probes for the Detection of 2,4,6-Trinitrophenol

A new fluorescent polyimide covalent organic framework (PI-COF) has been successfully synthesized through solvothermal route using tetra(4-aminophenyl) porphyrin and perylenetracarboxylic dianhydride, which possesses porous crystalline and excellent thermal stability (>500 °C). Furthermore, few-layered PI covalent organic nanosheets (PI-CONs) can be easily obtained from the fluorescent PI-COF through a facile liquid phase exfoliation approach, which were confirmed by atomic force microscopy and transmission electron microscopy analysis. It is interesting that the fluorescent intensity of PI-CONs is obviously enhanced relative to that of PI-COF. The PI-CONs have been successfully utilized as an efficient fluorescent probe for the highly sensitive and selective detection of 2,4,6-trinitrophenol (TNP). The mechanism might be attributed to the combination of electron transfer and inner filter effect based on DFT calculations and spectral overlap data. The system exhibits a good linear response toward TNP over the range from 0.5 to 10 μM with a detection limit of 0.25 μM.

One-Step Synthesis of Water-Soluble MoS2 Quantum Dots via a Hydrothermal Method as a Fluorescent Probe for Hyaluronidase Detection

In this work, a bottom-up strategy is developed to synthesize water-soluble molybdenum disulfide quantum dots (MoS2 QDs) through a simple, one-step hydrothermal method using ammonium tetrathiomolybdate [(NH4)2MoS4] as the precursor and hydrazine hydrate as the reducing agent. The as-synthesized MoS2 QDs are few-layered with a narrow size distribution, and the average diameter is about 2.8 nm. The resultant QDs show excitation-dependent blue fluorescence due to the polydispersity of the QDs. Moreover, the fluorescence can be quenched by hyaluronic acid (HA)-functionalized gold nanoparticles through a photoinduced electron-transfer mechanism. Hyaluronidase (HAase), an endoglucosidase, can cleave HA into proangiogenic fragments and lead to the aggregation of gold nanoparticles. As a result, the electron transfer is blocked and fluorescence is recovered. On the basis of this principle, a novel fluorescence sensor for HAase is developed with a linear range from 1 to 50 U/mL and a detection limit of 0.7 U/mL.

[X-linked lymphoproliferative syndrome type 1 complicated with secondary hemophagocytic lymphohistiocytosis and ileal perforation: case report and literature review]

OBJECTIVE

To analyze and summarize the clinical characteristics, laboratory tests and treatment of X-linked lymphoproliferative syndrome type 1 (XLP-1).

METHOD

A retrospective study was done in 2012 on an XLP-1 patient to collect the data on clinical manifestation, laboratory examination, gene and protein expression, complications and prognosis. Literatures were reviewed in Pubmed with the key word"X-linked lymphoproliferative syndrome".

RESULT

The patient with persistent high fever, jaundice, abdominal distension, hepatosplenomegaly and lymphadenectasis, rash and suspicious positive family history; the patient eventually died of hemophagocytic lymphohistiocytosis (HLH), with intestinal perforation, intestinal infection and bleeding after being infected with EB virus. This patient with SH2D1A gene exon 1 large fragment of the coding region of the nucleotide deletion and insertion mutations causing missense mutations (p.Leu25Lys) and nonsense mutations (stop codon TAG was inserted after missense mutation so that the protein encoded by the early termination of the 25 amino acids), which led to SAP protein missing. The expression of SAP in his mother was also partly missing. Retrieval of reports on XLP-1 was conducted through literature search (included totally 157 cases) at home and abroad, positive family history accounted for 60.6%(40/66); lymphoma incidence accounted for 49.7%(72/145); low gamma globulin occurred in 24.8%(39/157) of cases; secondary HLH ratio accounted for 43.3%(68/157); XLP-1 in patients with hemorrhagic enteritis and gastritis was low, accounted for only 2.6%(3/116).

CONCLUSION

XLP-1 patients occasionally develop necrotic enteritis complicated with ileal perforation.XLP-1 with large fragment deletion of SH2D1A gene might be associated with serious gastrointestinal manifestations.

A facile and one-step ethanol-thermal synthesis of MoS2 quantum dots for two-photon fluorescence imaging

MoS₂ quantum dots with two-photon fluorescence features are synthesized through a one-step solvothermal approach and successfully used for cellular bioimaging.

A label-free colorimetric sensor for Pb2+ detection based on the acceleration of gold leaching by graphene oxide

In this work, we developed a novel, label-free, colorimetric sensor for Pb(2+) detection based on the acceleration of gold leaching by graphene oxide (GO) at room temperature. Gold nanoparticles (AuNPs) can be dissolved in a thiosulfate (S2O3(2-)) aqueous environment in the presence of oxygen; however, the leaching rate is very slow due to the high activation energy (27.99 kJ mol(-1)). In order to enhance the reaction rate, some accelerators should be added. In comparison with the traditional accelerators (metal ions or middle ligands), we found that GO could efficiently accelerate the gold leaching reaction. Kinetic data demonstrate that the dissolution rate of gold in the Pb(2+)-S2O3(2-)-GO system is 5 times faster than that without GO at room temperature. In addition, the effects of surface modification and the nanoparticle size on the etching of AuNPs were investigated. Based on the GO-accelerated concentration-dependent colour changes of AuNPs, a colorimetric sensor for Pb(2+) detection was developed with a linear range from 0.1 to 20 μM and the limit of detection (LOD) was evaluated to be 0.05 μM. This colorimetric assay is simple, low-cost, label-free, and has numerous potential applications in the field of environmental chemistry.