The timing for embryo transfer after antibiotic therapy for chronic endometritis.

OBJECTIVE: To explore the optimal timing of embryo transfer after the first round treatment of chronic endometritis (CE) in vitro. MATERIALS AND METHODS: A total of 184 patients were recruited from a retrospective analysis of a large university-affiliated reproduction center in 2021. Some people chose to undergo embryo transfer in the same menstrual cycle with the first round of antibiotic treatment (Group 1, n = 29). Others received embryo transfer in the next cycle after the first round of treatment (Group 2, n = 69) or even one cycle later (Group 3，n = 96). RESULTS: Patients in Group 1 got significantly lower biochemical pregnancy rate and clinical pregnancy rate and live birth rate than Group 2 (p < 0.05) and also Group 3 (p < 0.05). Then after comparing the influence factors, we found embryo transfer in the next cycle after antibiotic treatment had a higher clinical pregnancy rate than group 1 (OR = 3.2 p < 0.05) and group 3(OR = 2.5, p < 0.05). The live birth rate in group 2 was higher than group 1(OR = 3.5, p < 0.05). CONCLUSION: These findings illustrate that embryo transfer in the next menstrual cycle is the optimal time. Embryo transfer in the same menstrual cycle with the first round of treatment reduces the pregnancy rate.

[Effect of Composite Leaching on Cadmium Removal Efficiency in Plow Layer Soil of Agricultural Land and Its Functional Regulation].

In order to explore the feasibility of soil leaching and the remediation of agricultural land polluted by medium (heavy) cadmium (Cd), the soil column was used to simulate in-situ leaching, and the citric acid (CA)+ferric chloride (FeCl3) composite leaching agent was selected. Under the optimal concentration combination and the addition amount of the composite leaching agent, the distribution characteristics of Cd in the plow-layer soil and below were investigated. The influence of the leaching process on soil health and the regulation effect of biochar were also investigated. The results showed that:① 0.1 mol·L-1 CA and 0.01 mol·L-1 FeCl3 were the best concentration combinations; under this concentration combination, when the eluent reached 9 pore volume, the content of Cd in the 20 cm soil column was lower than the risk screening value of 0.4 mg·kg-1 (GB 15618-2018) in the corresponding pH value of the tested soil after leaching. ② Under the optimal leaching conditions, the longitudinal distribution of Cd in the 60 cm soil column showed that the content of total Cd increased with the increase in soil depth after leaching, and the leachate of the soil column contained a certain amount of Cd, indicating that the leaching process promoted the downward migration of Cd. The content of available Cd in the soil after composite leaching also increased with the increase in soil depth, which was partly due to the change in exchangeable and carbonate-bound Cd in different soil layers. ③ A portion of the soil health indexes and enzyme activities decreased after CA+FeCl3 composite leaching. The addition of biochar can improve the health status of the soil after leaching; the soil health indexes and enzyme activities were restored significantly, and the risk of Cd reactivation also decreased after the addition of biochar. The results showed that part of Cd in the soil can be leached below the plow layer by CA+FeCl3 composite leaching; however, the leaching process may have a certain impact on soil health, and biochar has a significant effect on the recovery of soil after leaching.

Near-Infrared Light-Initiated Photoelectrochemical Biosensor Based on Upconversion Nanorods for Immobilization-Free miRNA Detection with Double Signal Amplification.

Photoelectrochemical (PEC) sensors are relatively new sensing platforms with high detection sensitivity and low cost. However, the current PEC biosensors dependent on ultraviolet or visible light as the exciting resource cause injuries to biological samples and systems, which restrains the applications in complicated matrixes. Herein, a near-infrared light (NIR)-initiated PEC biosensor based on NaYF4:Yb,Tm@NaYF4@TiO2@CdS (csUCNRs@TiO2@CdS) was constructed for sensitive detection of acute myocardial infarction (AMI)-related miRNA-133a in an immobilization-free format coupled with a hybridization chain reaction and a redox circle signal amplification strategy. A low-energy 980 nm NIR incident laser was converted to 300-480 nm light to excite the adjacent TiO2@CdS photosensitive shell to generate photocurrent by NaYF4:Yb,Tm@NaYF4 upconversion nanorods. Also, magnetic beads were employed for the homogeneous determination of target miRNA-133a to reduce the recognition steric hindrance and improve the detection sensitivity. The photocurrent response was positively correlated with the level of ascorbic acid as the energy donor to consume photoacoustic holes produced on the surface of csUCNRs@TiO2@CdS, which was generated by alkaline phosphatase catalyzation and regenerated by tris(2-carboxyethyl) phosphine reduction upon the appearance of miRNA-133a. Exerting a NIR-light-driven and immobilization-free strategy, the as-constructed biosensor displayed linearly sensitive and selective determination of miRNA-133a with a detection limit of 36.12 aM. More significantly, the assay method provided a new concept of the PEC sensing strategy driven by NIR light to detect diverse biomarkers with pronounced sensitivity, light stability, and low photodamage.

[Interaction and Mechanism Between Conditioning Agents and Two Elements in the Soil Enriched with Phosphorus and Cadmium].

Focusing on agricultural soil enriched in phosphorus and cadmium (total Cd=0.94 mg·kg-1 and total P=0.86g·kg-1), indoor cultivation experiments were conducted according to the length of the middle rice growth period and the following crop planting period in Hubei. The bioavailability of soil phosphorus and cadmium were examined along with their morphological changes and coupling effect under the influence of material biochar (BC), calcium magnesium phosphate fertilizer (CMP), and fly ash (FA). The results showed that:① When cultured for 140 days, the content of available phosphorus in the soil treated with the conditioning agents was significantly increased compared with the control soil, available phosphorus reached 22.47-37.81mg·kg-1, and the optimal growth requirements of rice were met without additional application of phosphate fertilizer, and adding BC had the best effect. ② The phosphorus in the test soil is mainly inorganic orthophosphate, and the content of different forms of inorganic phosphorus increased under the action of the conditioning agents. The fixed O-P and Ca10-P in the soil gradually changed to more active forms (Ca2-P, Ca8-P, Al-P and Fe-P) over time. ③ The effective Cd content of the soil treated with the conditioning agents was significantly reduced by 8.74%-17.48% relative to the control treatment, which was mainly related to the effect of the three conditioning agents on soil pH. At the same time, compared with the control, the addition of a conditioning agent significantly reduced the exchangeable Cd, and the carbonate-bound Cd and the residual Cd were increased. The abundance of active groups at the surface is related to the adsorption and chelation of Cd2+. The results showed that the three conditioners have the dual functions of phosphorus activation and cadmium passivation in phosphorus-and cadmium-enriched soil, and the effect of biomass carbon and calcium magnesium phosphate fertilizer was greatest, which persisted across the entire rice growth period to the sowing date of the next crop.

ACE2 and TMPRSS2 Expression in Hepatocytes of Chronic HBV Infection Patients.

Background: Pre-existing liver disease is a risk factor for the worse prognosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We aimed to evaluate whether chronic hepatitis B (CHB) and hepatocellular carcinoma (HCC) affect the expression of viral receptor angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) in the liver. Methods: Twelve pairs of matched liver tissues of HCC and para-carcinoma were collected from the First Affiliated Hospital of Zhejiang University School of Medicine. And 20 liver biopsies from CHB patients were collected from Peking University People's Hospital. The expression of ACE2 and TMRPSS2 were detected using immunofluorescence staining, western blot, and RT-qPCR. The effects of hepatitis B virus (HBV) replication or interferon on ACE2 and TMPRSS2 expression were tested in hepatic cell lines. Results: The mRNA expression of TMPRSS2 in HCC tissues was six-fold higher than that of para-carcinoma tissues (P = 0.002), whereas that of ACE2 was not statistically different between HCC and para-carcinoma tissues. Hepatocellular ACE2 expression was detected in 35% (7/20) of CHB patients and mostly distributed in the inflammatory areas. However, there was no difference in TMPRSS2 expression between areas with or without inflammation. IFN-α2b slightly induced ACE2 expression (2.4-fold, P = 0.033) in HepG2 cells but not in Huh-7, QSG-7701, and L-02 cells. IFN-α2b did not affect TMPRSS2 expression in these cell lines. In addition, HBV replication did not alter ACE2 expression in HepAD38 cells. Conclusions: Although HBV replication does not directly affect the expression of ACE2 and TMPRSS2, intrahepatic inflammation and carcinogenesis may increase their expression in some patients, which, in turn, may facilitate SARS-CoV-2 infection in hepatocytes.

DDX5-targeting fully human monoclonal autoantibody inhibits proliferation and promotes differentiation of acute promyelocytic leukemia cells by increasing ROS production.

Acute promyelocytic leukemia (APL) therapy involves the compounds cytotoxic to both malignant tumor and normal cells. Relapsed APL is resistant to subsequent chemotherapy. Novel agents are in need to kill APL cells selectively with minimal toxicity. DDX5 has been recognized to be a novel target to suppress acute myeloid leukemia (AML). However, the role of DDX5 remains elusive in APL. Here a DDX5-targeting fully human monoclonal autoantibody named after 2F5 was prepared. It is demonstrated that 2F5 selectively inhibited APL cell proliferation without toxicity to normal neutrophil and tissues. Moreover, 2F5 was confirmed to induce G0/G1 phase arrest in APL cells, and promote APL cell differentiation combined with decreased DDX5 expression and increased reactive oxygen species (ROS) production. Knockdown of DDX5 by siRNA also inhibited proliferation, promoted cell differentiation and enhanced ROS production in APL cells. However, the ROS inhibitor reversed the effects of 2F5 on DDX5 and ROS in APL cells. Thus, we conclude that DDX5-targeting 2F5 inhibits APL cell proliferation, and promotes cell differentiation via induction of ROS. 2F5 showed the therapeutic value of fully human monoclonal autoantibody in APL, which provides a novel and valid approach for treatment of relapse/refractory APL.

Efficacy of intra-arterial catheter-directed thrombolysis for popliteal and infrapopliteal acute limb ischemia.

OBJECTIVE: The purpose of this study was to examine the efficacy and safety of catheter-directed thrombolysis (CDT) for first-line treatment of popliteal and infrapopliteal acute limb ischemia. METHODS: A total of 28 consecutive patients (30 limbs) who underwent CDT for treatment of popliteal and infrapopliteal acute limb ischemia of thromboembolic origin between March 2012 and December 2017 were enrolled in this study. Per the Society for Vascular Surgery, limbs were classified into three runoff score groups: <5, good; 5 to 10, compromised; and >10, poor. The primary end points were primary patency and limb salvage assessed by Kaplan-Meier survival analysis. Secondary end points were technical success and clinical success. The Society for Vascular Surgery-recommended scale for gauging changes in clinical status was used to assess clinical success. Safety of the procedure was evaluated on the basis of periprocedural complications according to the Society of Interventional Radiology classification system. RESULTS: Technical success was achieved in 25 (83.33%) treated limbs. Improved clinical status (grade +3/+2) was achieved in 93.33% of limbs. Primary patency and limb salvage for the entire cohort were 76.67% and 90% at 6 months and 60.0% and 76.67% at 12 months, respectively. The patency rate at 6 months and 12 months was 91.67% and 83.33% for the good runoff group, 80% and 60% for the compromised runoff group, and 50% and 25% for the poor runoff group, respectively. The patency rate of the good runoff group was significantly higher compared with that of the poor runoff group (P = .004). Major amputation rate and mortality rate were 16.67% and 7.14%, respectively, at 12 months. The reintervention rate was 3.57% at 6 months and 21.42% at 12 months. CONCLUSIONS: CDT is safe and effective for revascularization of smaller vessel acute arterial thromboembolism as a primary therapy. However, more studies with a larger sample are warranted.

Near-Infrared Fluorescent Furin Probe for Revealing the Role of Furin in Cellular Carcinogenesis and Specific Cancer Imaging.

Furin, an important member in the family of proprotein convertases, is a participant in the activation of various precursor proteins. The expression level of furin stays in a very low range in most normal cells, but elevates with a big margin in many cancer cells. More importantly, furin is closely related to tumor formation and migration. Herein, a furin-activatable near-infrared (NIR) fluorescent probe (HD-F) was first developed that allowed for specific, sensitive detection and imaging of furin both in vitro and in vivo. HD-F consists of a classical NIR fluorophore (HD), a furin-particular polypeptide sequence RVRR, and a self-eliminating linker. Without the interaction with furin, no noticeable fluorescence enhancement was detected, even over 3 days, demonstrating the excellent stability of HD-F. Upon conversion by furin, there was a distinct signal increase around 708 nm. It has achieved assay and visualization of endogenous furin in various cells, tumor tissues, and tumor-bearing mouse models. Importantly, HD-F is well-suited for monitoring the change of furin expression level in the process of hypoxia-inducible factor-1 stabilized by CoCl2. Moreover, HD-F could visualize the divergence in the expression level of furin between normal and cancer cells, indicating its potential in specific cancer imaging. Thus, this novel probe is able to serve as a potential tackle for better understanding of the intrinsic link between a hypoxic physiological environment and cellular carcinogenesis and predicting cancer in preclinical applications.

Histone deacetylases up-regulate C/EBPα expression through reduction of miR-124-3p and miR-25 in hepatocellular carcinoma.

BACKGROUND: CCAAT enhancer binding protein α (C/EBPα), as an important transcription factor involved in cell proliferation, differentiation and metabolism, was up-regulated in primary hepatocellular carcinoma (HCC) and predicted poorer prognosis. In this study, we explored how histone deacetylases (HDACs) up-regulated C/EBPα in HCC. METHODS: The protein expressions of HDAC1, HDAC2 were associated with C/EBPα by immunohistochemistry staining in a HCC tissue microarray. HCC cells were then treated with HDAC inhibitors or siRNAs to determine the roles of miR-124-3p and miR-25 in the regulation of C/EBPα mRNA expression. RESULTS: Both HDAC1 and HDAC2 proteins were significantly associated with C/EBPα. Inhibition of HDAC by either pharmacological inhibitors or siRNAs decreased C/EBPα mRNA expression in dose-dependent manners in HCC cells. HDAC inhibitors reduced C/EBPα mRNA stability as shown by pmiRGLO luciferase reporter assays. HDAC inhibition consistently induced miR-124-3p and miR-25 expression. Conversely, blockage of miR-124-3p and/or miR-25 by treatment with specific synthetic inhibitors abolished C/EBPα reduction. More importantly, C/EBPα mRNA stability could be rescued by site-directed mutations of miR-124-3p or miR-25 recognition sites in the C/EBPα 3'UTR sequence. In summary, HDAC may up-regulate C/EBPα expression through miR-124-3p and miR-25 in HCC.

Midlife Long-Hour Working and Later-life Social Engagement Are Associated with Reduced Risks of Mild Cognitive Impairment among Community-Living Singapore Elderly.

Mild cognitive impairment (MCI), as a transitional stage between normal aging and dementia, causes cognitive decline among one-fifth of elders aged 65 years and older. Health-related lifestyles (HRL) are generally regarded as modifiable influencing factors of cognitive decline. The present study investigated how HRLs at two different life stages (one at midlife and the other at later life) affect MCI occurrence among community-dwelling elders, as part of the Diet and Healthy Aging (DaHA) study in Singapore. The frequencies of major HRL activities were compared between 119 clinical diagnosed MCI cases and 632 normal aging controls with functional cognition. The associations of HRLs with MCI were determined by multivariate logistic regression analysis and adjusted according to known factors including age, childhood education, and major chronic diseases (hypertension, stroke, diabetes, and cataracts or glaucoma). Long-hour working in midlife (adjusted OR = 0.418 with 95% CI 0.215-0.812) and social engagement in later-life (adjusted OR = 0.532 with 95% CI 0.329-0.859) were associated with reduced risks of MCI, respectively. It is important to note that those elders who had both midlife long-hour working and later-life social engagement were related to the lowest risk of MCI (adjusted OR = 0.285 with 95% CI 0.143-0.565), when compared to the least active subgroup who neither had worked long hours in midlife nor participate in social activities in later-life. Therefore, the present study demonstrated that midlife long-hour working and later-life social engagement were modifiable factors for the maintenance of cognitive functions.

Engineering of a bioluminescent probe for imaging nitroxyl in live cells and mice.

A bioluminescent probe, BP-HNO, which exhibits a turn-on response to nitroxyl with high sensitivity and selectivity, is reported for the first time in this work. BP-HNO is free from the interference of biological autofluorescence to afford a high signal-to-noise ratio for bioimaging, and was successfully applied to imaging nitroxyl in live cells and mice.

Varacin-1, a novel analog of varacin C, induces p53-independent apoptosis in cancer cells through ROS-mediated reduction of XIAP.

Varacin C is a promising anticancer agent and possesses acid-promoted and photo-induced DNA-damaging activities. In this study, we synthesized an analog varacin-1 (VCA-1) and examined its anticancer potentials. The results demonstrated that VCA-1 caused dose-dependent apoptotic cell death in cancer cells. Note that this action is independent of p53 status, because VCA-1 induced similar levels of apoptosis in two different panels of cell lines (HCT116 p53- wild-type vs. HCT116 p53-knockout colon cancer cells, and p53-expressing U2OS vs. p53-deficient saos2 osteosarcoma cancer cells). VCA-1-induced apoptosis was found to be mainly via the extrinsic apoptosis pathway involving caspase-8 activation and XIAP reduction. Forced over-expression of XIAP markedly prevented apoptosis, indicating its essential role in VCA-1 induced apoptosis. On the other hand, VCA-1 treatment enhanced intracellular ROS (reactive oxygen species) generation also in a p53-independent manner, and consequently promoted caspase activation. Pretreatment of N-acetyl cysteine (an antioxidant), rather than z-VAD (specific caspase inhibitor), markedly prevented XIAP reduction, suggesting that XIAP reduction may be resulted from oxidative stress. In conclusion, data from this study reveal the essential roles of ROS generation and XIAP reduction in VCA-1-induced apoptosis in cancer cells. VCA-1 may be a novel cancer therapeutic agent, especially in p53-mutant human cancers.

Ultrathin two-dimensional covalent organic framework nanoprobe for interference-resistant two-photon fluorescence bioimaging.

The complex environment of living organisms significantly challenges the selectivity of classic small-molecule fluorescent probes for bioimaging. Due to their predesigned topological structure and engineered internal pore surface, covalent organic frameworks (COFs) have the ability to filter out coexisting interference components and help to achieve accurate biosensing. Herein, we propose an effective interference-resistant strategy by creating a COF-based hybrid probe that combines the respective advantages of COFs and small-molecule probes. As a proof of concept, a two-photon fluorescent COF nanoprobe, namely TpASH-NPHS, is developed for targeting hydrogen sulfide (H2S) as a model analyte. TpASH-NPHS exhibits limited cytotoxicity, excellent photostability and long-term bioimaging capability. More importantly, compared with the small-molecule probe, TpASH-NPHS achieves accurate detection without the interference from intracellular enzymes. This allows us to monitor the levels of endogenous H2S in a mouse model of cirrhosis.

Aptamer-functionalized nanoscale metal-organic frameworks for targeted photodynamic therapy.

Photodynamic therapy (PDT) has been applied in clinical cancer treatment. Here we report an aptamer-functionalized nanoscale metal-organic framework for targeted PDT. Our nanosystem can be easily prepared and successfully used for targeted PDT with a significantly enhanced therapeutic efficacy in vitro and in vivo. Methods: By combining the strong binding ability between phosphate-terminated aptamers and Zr-based nanoscale metal-organic frameworks (Zr-NMOFs) and the intercalation of photosensitizer TMPyP4 within the G-quadruplex DNA structure, TMPyP4-G4-aptamer-NMOFs were prepared. The characteristics and photodynamic performance of TMPyP4-G4-aptamer-NMOFs were examined after preparation. Then, we studied their stability, specific recognition ability, and phototoxicity in vitro. For in vivo experiments, the nanosystem was intratumorally injected into a HeLa subcutaneous xenograft tumor mouse model. After irradiation on day 0, mice were further injected with the nanosystem on day 5 and were again subjected to laser irradiation for 30 min. Tumor volumes and body weights of all mice were measured by caliper every 2 days after the treatment. Results: The nanosystem induced 90% cell death of targeted cells. In contrast, the control cells maintained about 40% cell viability at the same concentration of nanosystem. For the in vivo experiments, the nanosystem-treated group maintained more than 76% inhibition within the entire experimental period. Conclusion: We have demonstrated that our smart TMPyP4-G4-sgc8-NMOFs nanosystem can be used for targeted cancer therapy with high efficiency.

In Situ Imaging of Furin Activity with a Highly Stable Probe by Releasing of Precipitating Fluorochrome.

Furin, a kind of trans-Golgi proprotein convertases, plays important role in various physiological processes. It is overexpressed in many cancers and relates to tumor growth and migration. In situ detection and imaging of furin is of great significance for obtaining real-time information about its activity. However, the previously reported fluorescent probes for furin usually failed to realize in situ detection and long-term bioimaging, because these probes are based on water-soluble fluorophores, which tend to diffuse away from the reaction sites after converted by furin. Such a problem can be addressed by designing a probe, which releases a precipitating fluorophore upon furin conversion. Herein, we developed a probe HPQF for in situ detection of endogenous furin activity and long-term bioimaging by integrating a strictly insoluble solid-state fluorophore 6-chloro-2-(2-hydroxyphenyl) quinazolin-4(3H)-one (Cl-HPQ) with a furin specific peptide substrate (RVRR) through a self-immolative linker. The HPQF probe shows high selectivity and sensitivity to furin. Upon converted by furin, HPQF releases free Cl-HPQ, which precipitates near the enzyme active site. The precipitates emit bright solid-state fluorescence for in situ imaging. HPQF could truly visualize the location of intracellular furin, which was further confirmed by colocalization and immunofluorescence experiments. Excitingly, the long-term bioimaging was also achieved benefiting from its outstanding signal-stability and antidiffusion ability. HPQF was further utilized to monitor the level change of furin under stabilizing of hypoxia-inducible factor (HIF) regulated by cobalt chloride (CoCl2) as well as visualization of furin in MDA-MB-468 cell tumor tissues.

A Bioluminescent Probe for Imaging Endogenous Peroxynitrite in Living Cells and Mice.

Peroxynitrite (ONOO-), an extremely reactive nitrogen species (RNS), is implicated in diverse pathophysiological conditions, including cancer, neurodegenerative diseases, and inflammation. Sensing and imaging of ONOO- in living systems remains challenging due to the high autofluorescence and the limited light penetration depth. In this work, we developed a bioluminescent probe BP-PN, based on luciferase-luciferin pairs and the ONOO--responded group α-ketoamide, for highly sensitive detection and imaging of endogenous ONOO- in living cells and mice for the first time. Attributed to the BL without external excitation, the probe BP-PN exhibits a high signal-to-noise ratio with relatively low autofluorescence. Furthermore, we examine the application of the probe BP-PN using the mice model of inflammation, and BP-PN shows high sensitivity for imaging endogenous ONOO- in inflamed mice. This newly developed bioluminescent probe would be a potentially useful tool for in vivo imaging of ONOO- in wider physiological and pathological processes.

Two-Photon DNAzyme-Gold Nanoparticle Probe for Imaging Intracellular Metal Ions.

RNA-cleaving DNAzymes have been demonstrated as a promising platform for sensing metal ions. However, the poor biological imaging performance of RNA-cleaving DNAzyme-based fluorescent probes has limited their intracellular applications. Compared with traditional one-photon fluorescence imaging, two-photon (TP) fluorescent probes have shown advantages such as increased penetration depth, lower tissue autofluorescence, and reduced photodamage. Herein, for the first time, we developed an RNA-cleaving DNAzyme-based TP imaging probe (TP-8-17ES-AuNP) for Zn2+ detection in living cells by modifying a Zn2+-specific DNAzyme (8-17) with a TP fluorophore (TP-8-17ES) and using gold nanoparticles (AuNPs) for intracellular delivery. The modified TP-8-17ES exhibits good two-photon properties and excellent photostability. For the TP-8-17ES-AuNP, in the absence of Zn2+, the TP fluorophore is quenched by both AuNPs and the molecular quencher. Only in the presence of Zn2+ does the DNAzyme cleave the TP fluorophore-labeled substrate strand, resulting in fluorescence enhancement and TP imaging. Such probe shows remarkable selectivity of Zn2+ over other metal ions existing in the biological environment. Benefiting from the labeled TP fluorophore, the near-infrared (NIR) excited probe has the capability of TP imaging of Zn2+ in living cells and tissue with a deep tissue penetration up to 160 µm. This method can be generally applied to detect other metal ions in biological systems under TP imaging with higher tissue penetration ability and lower phototoxicity.

Autofluorescence-Free Targeted Tumor Imaging Based on Luminous Nanoparticles with Composition-Dependent Size and Persistent Luminescence.

Optical bioimaging is an indispensable tool in modern biology and medicine, but the technique is susceptible to autofluorescence interference. Persistent nanophosphors provide an easy-to-perform and highly efficient means to eliminate tissue autofluorescence. However, direct synthesis of persistent nanophosphors with tunable properties to meet different bioimaging requirements remains largely unexplored. In this work, zinc gallogermanate (Zn1+xGa2-2xGexO4:Cr, 0 ≤ x ≤ 0.5, ZGGO:Cr) persistent luminescence nanoparticles with composition-dependent size and persistent luminescence are reported. The size of the ZGGO:Cr nanoparticles gradually increases with the increase of x in the chemical formula. Moreover, the intensity and decay time of persistent luminescence in ZGGO:Cr nanoparticles can also be fine-tuned by simply changing x in the formula. In vivo bioimaging tests demonstrate that ZGGO:Cr nanoparticles can efficiently eliminate tissue autofluorescence, and the nanoparticles also show good promise in long-term bioimaging as they can be easily reactivated in vivo. Furthermore, an aptamer-guided ZGGO:Cr bioprobe is constructed, and it displays excellent tumor-specific accumulation. The ZGGO:Cr nanoparticles are ideal for autofluorescence-free targeted bioimaging, indicating their great potential in monitoring cellular networks and construction of guiding systems for surgery.

In vivo imaging of alkaline phosphatase in tumor-bearing mouse model by a promising near-infrared fluorescent probe.

Alkaline phosphatase (ALP), one of the important hydrolases, is associated with the progress of many diseases as a well-defined biomarker. Fluorescence imaging of ALP in living organisms is of great importance for biological studies. However, in vivo detection of ALP remains a great challenge because current fluorescent probes show short excitation and emission wavelength, which are not desired for in vivo fluorescence imaging. Herein we reported a near-infrared (NIR) fluorescent probe (NALP) for turn-on trapping of ALP activity in living cancer cells and tumors. NALP was composed of a NIR-emitting fluorophore as a reporter and phosphate as a triggered moiety. Phosphate group was directly tethered to the hydroxyl group of fluorophore, which prohibited the fluorescence. The probe exhibited a high selectivity and remarkable fluorescence turn-on response to ALP in aqueous solutions with a detection limit of 0.28U/L. Benefiting from NIR excitation and emission, high contrast on the imaging signal could be achieved in response to endogenous ALP activity. Impressively, not only we successfully used NALP for imaging of endogenous ALP activity in cancer cells, but also, applied it for fluorescence imaging of ALP in tumor tissues and living tumor xenograft in nude mice for the first time. The probe was expected to be promising tool for practical application in disease diagnosis on the roles of ALP in disease.

In Situ Localization of Enzyme Activity in Live Cells by a Molecular Probe Releasing a Precipitating Fluorochrome.

Current enzyme-responsive, fluorogenic probes fail to provide in situ information because the released fluorophores tend to diffuse away from the reaction sites. The problem of diffusive signal dilution can be addressed by designing a probe that upon enzyme conversion releases a fluorophore that precipitates. An excited-state intramolecular proton transfer (ESIPT)-based solid-state fluorophore HTPQ was developed that is strictly insoluble in water and emits intense fluorescence in the solid state, with λex/em =410/550 nm, thus making it far better suited to use with a commercial confocal microscope. HTPQ was further utilized in the design of an enzyme-responsive, fluorogenic probe (HTPQA), targeting alkaline phosphatase (ALP) as a model enzyme. HTPQA makes possible diffusion-resistant in situ detection of endogenous ALP in live cells. It was also employed in the visualizing of different levels of ALP in osteosarcoma cells and tissue, thus demonstrating its interest for the diagnosis of this type of cancer.