Label-Free, Reusable, Equipment-Free, and Visual Detection of Hydrogen Sulfide Using a Colorimetric and Fluorescent Dual-Mode Sensing Platform.

In this work, we have found for the first time that the fluorescence of rhodamine B (RhB) would be dramatically reduced after it bound to hemin/G-quadruplex and reacted with •OH. Based on this finding, we have designed a colorimetric and fluorescent dual-mode sensing platform for visual detection of hydrogen sulfide (H2S). The constructed sensor is based on the formation of dsDNA and the G-quadruplex structure by the cytosine-Ag+-cytosine mismatch, causing H2O2-mediated catalysis to oxidize ABTS or RhB to induce a colorimetric or fluorescent change. In the presence of H2S, the solution color for colorimetric and fluorescent assays would change from dark green to pink and from green (fluorescence off) to bright yellow (fluorescence on), respectively. This dual-mode assay showed high selectivity toward H2S over other interference materials with a low measurable detection limit value (below than 2.5 µM), and it has been successfully applied to H2S visual detection in real samples. Moreover, the dual-mode sensing strategy presented an excellent reutilization character both in colorimetric and fluorescent assays. This method was employed as a label-free, simple, fast, and equipment-free platform for H2S detection with high selectivity and reusability. This work realized naked-eye detection both in colorimetric and fluorescent analysis at a lower concentration of H2S, demonstrating a promising strategy for on-site visual detection of H2S.

Triarylboron-Based High Photosensitive Probes for Apoptosis Detection, Tumor-Targeted Imaging, and Selectively Inducing Apoptosis of Tumor Cells by Photodynamics.

Herein, a series of triarylboron-based fluorescent probes were developed for distinguishing apoptosis from living cells and even necrosis. They also demonstrate high photosensitivity because they can produce detectable reactive oxygen species (ROS) under an ultra-low light power density (1.5 mW/cm2). By changing the peripheral groups to regulate the performance, we identified a multifunctional probe, TAB-6-amyl, which can be used not only for selectively imaging apoptosis but also for the targeted imaging of SKOV-3 cells in vitro and in vivo. It could further specifically induce the apoptosis of SKOV-3 cells under light irradiation. During the study, we also found that TAB-6-amyl can cross the blood-brain barrier (BBB). Therefore, another probe based on this kind of structure, TAB-5-M-1-cRGD, was constructed for the targeted imaging of brain glioma cells and inducing their apoptosis. This study offers some promising tools for apoptosis detection and tumor photodynamic therapy (PDT).

Isolation of Natural DNA Aptamers for Challenging Small-Molecule Targets, Cannabinoids.

Aptamers are nucleic acid-based affinity reagents that are isolated via an in vitro process known as systematic evolution of ligands by exponential enrichment (SELEX). Despite their great potential for a wide range of analytical applications, there are relatively few high-quality small-molecule binding aptamers, especially for "challenging" targets that have low water solubility and/or limited moieties for aptamer recognition. The use of libraries containing chemically modified bases may improve the outcome of some SELEX experiments, but this approach is costly and yields inconsistent results. Here, we demonstrate that a thoughtfully designed SELEX procedure with natural DNA libraries can isolate aptamers with high affinity and specificity for challenging small molecules, including targets for which such selections have previously failed. We first isolate a DNA aptamer with nanomolar affinity and high specificity for (-)-trans-Δ9-tetrahydrocannabinol (THC), a target previously thought to be unsuitable for SELEX with natural DNA libraries. We subsequently isolate aptamers that exhibit high affinity and cross-reactivity to two other challenging targets, synthetic cannabinoids UR-144 and XLR-11, while maintaining excellent specificity against a wide range of non-target interferents. Our findings demonstrate that natural nucleic acid libraries can yield high-quality aptamers for small-molecule targets, and we outline a robust workflow for isolating other such aptamers in future selection efforts.

Label-Free, Visual Detection of Small Molecules Using Highly Target-Responsive Multimodule Split Aptamer Constructs.

Colorimetric aptamer-based sensors offer a simple means of on-site or point-of-care analyte detection. However, these sensors are largely incapable of achieving naked-eye detection, because of the poor performance of the target-recognition and signal-reporting elements employed. To address this problem, we report a generalizable strategy for engineering novel multimodule split DNA constructs termed "CBSAzymes" that utilize a cooperative binding split aptamer (CBSA) as a highly target-responsive bioreceptor and a new, highly active split DNAzyme as an efficient signal reporter. CBSAzymes consist of two fragments that remain separate in the absence of target, but effectively assemble in the presence of the target to form a complex that catalyzes the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid, developing a dark green color within 5 min. Such assay enables rapid, sensitive, and visual detection of small molecules, which has not been achieved with any previously reported split-aptamer-DNAzyme conjugates. In an initial demonstration, we generate a cocaine-binding CBSAzyme that enables naked-eye detection of cocaine at concentrations as low as 10 µM. Notably, CBSAzyme engineering is straightforward and generalizable. We demonstrate this by developing a methylenedioxypyrovalerone (MDPV)-binding CBSAzyme for visual detection of MDPV and 10 other synthetic cathinones at low micromolar concentrations, even in biological samples. Given that CBSAzyme-based assays are simple, label-free, rapid, robust, and instrument-free, we believe that such assays should be readily applicable for on-site visual detection of various important small molecules such as illicit drugs, medical biomarkers, and toxins in various sample matrices.

Mechanism of Magnolia Volatile Oil in the Treatment of Acute Pancreatitis Based on GC-MS, Network Pharmacology, and Molecular Docking.

Objective: Magnoliae officinalis cortex (MOC) is one of the most frequently used traditional Chinese medicine (TCM) for the treatment of acute pancreatitis (AP). Magnolia volatile oil (MVO) is considered to be one of the main active ingredients in MOC for AP treatment. However, the underlying mechanism of MVO in AP therapy is unknown. Methods: An integrated strategy of gas chromatography-mass spectrum (GC-MS), network pharmacology, and molecular docking simulation was employed to predict underlying mechanism of MVO in AP treatment. First, the compounds of MVO were identified by GC-MS, and the targets of the identified characteristic compounds were collected from several databases, as well as AP-related targets. Next, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were carried out to obtain the mechanism. Moreover, the binding activity between core therapeutic targets and their corresponding compounds was evaluated by molecular docking simulation. Results: GC-MS results showed a total of 35 compounds that appeared in at least 18 out of 20 chromatograms were considered as characteristic compounds of MVO, and 33 compounds of those were identified. Network analysis demonstrated that 33 compounds regulated 142 AP-related targets. Of those, 8 compounds (α-eudesmol, γ-eudesmol, (-)-terpinen-4-ol, terpineol, hinesol, linalool, borneol, and ß-eudesmol) and 8 targets (TNF, IL-1ß, PPARγ, PPARα, PTGS2, NCOA1, CNR1, and ESR1) have a close relationship with AP treatment and were recognized as the key active compounds and the core therapeutic targets, respectively. The 142 targets were involved in both inflammation and calcium overload-related biological pathways, such as neuroactive ligand-receptor interaction, estrogen, MAPK, and calcium signaling pathway. Moreover, molecular docking simulation indicated that the 8 core therapeutic targets strongly interacted with their corresponding compounds. Conclusions: In summary, the present study elucidated that the efficacy of MVO in AP treatment might be attributed to anti-inflammation and inhibition of calcium overload through multicomponents and multitargets.

Molecular-engineered highly photosensitive triarylphosphine oxide compounds for apoptosis imaging and selectively inducing apoptosis of tumor cells by photodynamic therapy.

Although photodynamic therapy (PDT) has wide applications, tumor-targeting probes with high photosensitivity or apoptosis-monitoring capability, which possess low phototoxicity and can be used for evaluating therapeutic efficacy, are still scarce. In this study, we constructed a series of highly photosensitive probes by introducing multivalent positive charges around propeller-like triarylphosphine oxide compounds. Some of them can be used to detect apoptosis by selectively entering apoptotic cells in the presence of living or necrotic cells. Among them, OTPP-6-Amyl can target SKOV-3 cells by binding to their membrane in a short time and move to mitochondria with prolonging time and can be further applied for imaging SKOV-3 tumors in vivo, whereas for various apoptotic cells, it mainly enters the nucleus. Its high photosensitivity can be used to induce apoptosis in SKOV-3 cells without affecting the survival of other cells. By functionalizing with cRGD, another probe was constructed to target U87MG cells and induce their apoptosis by PDT, and it can also pass through the blood-brain barrier.

Visual detection of aflatoxin B1 and zearalenone via activating a new catalytic reaction of "naked" DNAzyme.

Here, we have found for the first time that the catalytic activity of "naked" DNAzyme, a single-stranded G-quadruplex DNAzyme (S.DNAzyme), can be modulated by aflatoxin B1 (AFB1) and zearalenone (ZEN). In fact, S.DNAzyme can mimic the activity of horseradish peroxidase to perform oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) to colored ABTS˙+ (dark green). This catalytic activity can be inhibited upon addition of AFB1, leading to color fade of the solution. But with ZEN, the solution color will change to a yellowish-brown or yellow color. Thus, we have exploited this finding to achieve label-free, naked-eye detection of AFB1 or ZEN, and have explored the possible detection mechanisms. This approach is able to detect AFB1 and ZEN concentrations as low as 0.18 µM and 0.29 µM, respectively. Even in real samples, the limit of detection values of these two analytes are lower than 3 µM. Notably, S.DNAzyme cross-reacted with three other tested aflatoxins, including aflatoxin B2, aflatoxin G1 and aflatoxin M1, revealing the potential for a broadly applicable method to identify the family of aflatoxins. The AFB1- or ZEN-triggered new catalytic reaction between "naked" DNAzyme and ABTS may offer new opportunities for on-site visual detection of mycotoxins.

A cancer-specific activatable theranostic nanodrug for enhanced therapeutic efficacy via amplification of oxidative stress.

Rationale: Despite considerable advances, the reactive oxygen species (ROS)-mediated cancer treatment suffers from the problems of up-regulation of adaptive antioxidants in cancer cells as well as side effects to normal cells. Therefore, development of a new generation of cancer-specific nanomedicine capable of amplifying oxidative stress would be of great interest for accurate and effective cancer treatment. Methods: Herein, transferrin (Tf)-decorated, dihydroartemisinin (DHA), L-buthionine-sulfoximine (BSO), and CellROX-loaded liposomal nanoparticles (Tf-DBC NPs) were developed for precise cancer theranositcs. Tf-DBC NPs could specifically recognize cancer cells via Tf-Tf receptor binding and be uptaken into the lysosomes of cancer cells, where Tf-DBC NPs were activated to release Fe(II), DHA, and BSO. ROS was generated by DHA in the presence of Fe(II), and GSH was depleted by BSO to disrupt the redox balance in cancer cells. Furthermore, CellROX, as a fluorescent probe for imaging of intracellular oxidative stress, was used to monitor the therapeutic efficacy. Results: The integration of Tf, DHA, and BSO into the acidic pH-responsive liposomes selectively and effectively killed cancer cells and prevented the oxidative injury to normal cells. The high oxidative state was visualized at the tumor site and the amplification of oxidative stress enabled tumor eradication by Tf-DBC NPs, demonstrating the successful implementation of this novel strategy in vivo. Conclusion: Our study provides a new paradigm for the design of ROS-mediated therapeutics and offers a promising perspective for precise cancer treatment.

Artemisinin-Based Smart Nanomedicines with Self-Supply of Ferrous Ion to Enhance Oxidative Stress for Specific and Efficient Cancer Treatment.

Though abundant researches report that artemisinin could inhibit cancer cell growth via generating toxic reactive oxygen species (ROS), the therapeutic efficiency of artemisinin for cancer treatment is still limited owing to the insufficient intracellular ferrous ion and defensive effect of intracellular glutathione. Herein, we report a cathepsin B-controllable smart nanomedicine based on the structural and pharmacodynamic characteristics of artemisinin, which employed transferrin-peptide-modified mesoporous silica to codeliver artemisinin and buthionine-sulfoximine, a glutathione scavenger, into cancer cells. As a gatekeeper, the transferrin-peptide can not only target the cancer cells but also supply the extra ferrous iron to catalyze artemisinin to produce excessive ROS to kill cancer cells efficiently. Once the designed nanomedicine attack into lysosome of tumor cells, the cargos of nanomedicine can be released in the presence of cathepsin B to immediately activate self-amplification of oxidative stress by simultaneously elevating the levels of ROS and weakening the levels of glutathione. We anticipate that this rational design strategy provides innovative opportunities for artemisinin in the clinical application of cancer.

An artemisinin-mediated ROS evolving and dual protease light-up nanocapsule for real-time imaging of lysosomal tumor cell death.

Lysosomes are critical organelles for cellular homeostasis and can be used as potential targets to kill tumor cells from inside. Many photo-therapeutic methods have been developed to overproduce reactive oxygen species (ROS) to trigger lysosomal membrane permeabilization (LMP)-associated cell death pathway. However, these technologies rely on extra irradiation to activate the photosensitizers, which limits the applications in treating deep seated tumors and widespread metastatic lesions. This work reports a multifunctional nanocapsule to achieve targeted lysosomal tumor cell death without irradiation and real-time monitoring of drug effect through encapsulating artemisinin and dual protease light-up nanoprobe in a folate-functionalized liposome. The nanocapsule can be specifically uptaken by tumor cells via folate receptor-mediated endocytosis to enter lysosomes, in which artemisinin reacts with ferrous to generate ROS for LMP-associated cell death. By virtue of confocal fluorescence imaging, the artemisinin location in lysosome, ROS-triggered LMP and ultimate cell apoptosis can be visualized with the cathepsin B and caspase-3 activatable nanoprobe. Notably, the artemisinin-mediated ROS evolving for tumor therapy and real-time therapeutic monitoring were successfully implemented by living imaging in tumor-bearing mice, which broaden the nanocapsule for in vivo theranostics and may offer new opportunities for precise medicine.

A Programmed Nanoparticle with Self-Adapting for Accurate Cancer Cell Eradication and Therapeutic Self-Reporting.

To achieve the best therapeutic efficacy and good prognosis, the drugs necessitate tailored profiles of excellent spatiotemporal control and therapeutic monitoring. Here we introduce a programmed theranostic nanoparticle with self-adapting properties for tumor-specific systemic treatment, including stealthy surface to prolong circulation time in blood, surface charge-reversion for tumor targeting, receptor-mediated internalization to increase intracellular accumulation, "proton sponge effect" for controllable drug release and escape from endo/lysosome. Encouragingly, in the process of drug-induced apoptosis, the therapeutic efficacy can be reported by fluorescence imaging in vivo, in situ and in real time. Therefore, this work provides a new paradigm for design of programmed theranositc nanomedicine and offers promising prospects for precise tumor treatment.

Pegylated folate and peptide-decorated graphene oxide nanovehicle for in vivo targeted delivery of anticancer drugs and therapeutic self-monitoring.

This work reports a graphene oxide-based nanovehicle with conjugation of pegylated folate for targeted delivery of anticancer drugs and fluorescein-labeled peptide for therapeutic self-monitoring in vitro and in vivo. The nanovehicle could absorb hydrophobic and aromatic drug molecules with high loading capacity and efficiency of more than 1.7 mg mg(-1) and 90%, respectively. MTT and flow cytometric assays demonstrated that the drug-loaded nanovehicle could specifically transport and release the drugs into the folate receptor high-expressed cancer cells, which ensured a high therapeutic efficiency to cancer cells and prevented the injury to normal cells. Moreover, confocal fluorescence imaging confirmed that the drug-induced cancer cell death could be visualized with the light-up fluorescence of fluorescein activated by caspase-3. The targeted delivery of drug and self-evaluation of therapeutic efficacy were further successfully realized by living imaging in tumor-bearing mice, which broaden the applications of this theranostic system in vivo and may offer new opportunities for precise cancer treatment.

[Prevalence and risk factors of postpartum depression in Tianhe District of Guangzhou].

OBJECTIVE: To investigate the prevalence and risk factors of postpartum depression (PPD) in Tianhe district of Guangzhou. METHODS: A total of 1428 postpartum women in 3 hospitals in Tianhe District of Guangzhou were screened with Edinburg Postnatal Depression Scale (EPDS), Social Support Rating Scale (SSRS) and a self-designed questionnaire of PPD-related factors during the period from May to September, 2013. RESULTS: The prevalence of PPD was 20.03% in these women. Unconditional logistic regression analysis showed a significant correlation of PPD with education, delivery mode, only daughter, relationship between mother-in-law and daughter-in-law, newborn gender satisfaction and housing condition (P<0.05). Multivariate logistic regression analysis identified education, delivery mode, only daughter, relationship between mother-in-law and daughter-in-law, and newborn gender satisfaction as the risk factors for PPD, and housing condition was negatively correlated with the incidence of PPD with an OR value of 0.900. Compared with healthy postpartum women, the patients with PPD exhibited significantly reduced total score of social support rating scale, score of objective support, score of subjective support, and social utilization degree. CONCLUSION: The prevalence of PPD is high in Tianhe District of Guangzhou, and health education and psychosocial intervention should be offered to prevent PPD.

Prevalence and risk factors of postpartum depression in a population-based sample of women in Tangxia Community, Guangzhou.

OBJECTIVE: To investigate the prevalence and analyze the risk factors of postpartum depression (PPD) in Tangxia Community, Guangzhou, a community representative of the process of urbanization in China. METHODS: A total of 1 823 delivery women in Tangxia Community, Guangzhou were screened with the Chinese Version of Edinburgh Postnatal Depression Scale, Hamilton Depression Scale and Social Support Rating Scale. The risk factors were evaluated by self-made questionnaire based on literature interview combined with expert consultation. The data collected were analyzed using Student's t test and logistic regression in SPSS16.0. RESULTS: The prevalence of PPD in Tangxia Community, Guangzhou was 27.37%. Mutivariant logistic regression analysis identified mode of delivery, puerperant from one-child family, relationship between mother-in-law and daughter-in-law and fetus gender as the risk factors of PPD while housing condition was negatively correlated with the incidence of PPD with OR value of 0.82.The the total score of social support rating scale, the score of objective support, subjective support and social utilization degree were significantly reduced in women with PPD in contrast with women without PPD. CONCLUSIONS: The incidence of PPD was slightly higher than other regions of China. It's of great importance to distinguish risk factors in regional culture context and develop health promotion program in order to enhance the well-being of delivery women.