ClO- Induced Dual-Excitation Fluorescent Probes Responding to Diverse Testing Modes with Ratio Methodology.

Single-excitation ratio fluorescent probes have enabled the output signal with high signal-to-noise ratio, but are still plagued with technique challenges, including signal distortion and limited application scenario. Herein, a dual-excitation near-infrared (NIR) fluorescent probe P1 of coumarin derivatives is constructed, showing high signal output ability in the visible region and high tissue penetration depth ability in the NIR region. As NIR probe P1 selectively recognizes ClO-, the emission signal in the visible region (480 nm) of P1 is enhanced during the recognition process. Meanwhile, the NIR emission (830 nm) of the conjugated system is weakened, finally realizing that ClO- triggered the dual-excitation (720/400 nm) ratio fluorescence signal detection and monitoring. The signal of detection in vitro has high responsiveness. Meanwhile, in the process of NIR monitoring in vivo, positive contrast imaging of fluorescence is constructed, which can accurately monitor ClO- changes over time. The current dual-excitation fluorescence-based data calibration and/or comparison method improves the application of the traditional single-excitation ratio fluorescence strategy and provide innovative detection tools for accurate measurement of fluorescence detection, with detection/monitoring modes suitable for different physiological environments.

Association between vaginal microbiota and the progression of ovarian cancer.

Ovarian cancers, especially high-grade serous ovarian cancer (HGSOC), are one of the most lethal age-independent gynecologic malignancies. Although pathogenic microorganisms have been demonstrated to participate in the pathogenesis of multiple types of tumors, their potential roles in the development of ovarian cancer remain unclear. To gain an insight into the microbiome-associated pathogenesis of ovarian cancer and identify potential diagnostic biomarkers, we applied different techniques to analyse the microbiome and serum metabolome of different resources. We found that the vaginal microbiota in ovarian cancer mouse models was under dysbiosis, with altered metabolite configurations that may result from amino acid or lysophospholipid metabolic processes. Local therapeutic intervention with a broad spectrum of antibiotics was effective in reversing microbiota dysbiosis and suppressing carcinogenic progression. As the ovary is situated deeply in the pelvis, it is difficult to directly monitor the ovarian microbial community. Our findings provide alternative options for utilizing the vaginal bacteria as noninvasive biomarkers, such as Burkholderia (area under the curve = 0.8843, 95% confidence interval: 0.743-1.000), which supplement the current invasive diagnostic methods for monitoring ovarian cancer progression and contribute to the development of advanced microbe-based diagnosis and adjuvant therapies.

A two-photon fluorescence silica nanoparticle-based FRET nanoprobe platform for effective ratiometric bioimaging of intracellular endogenous adenosine triphosphate.

Two-photon fluorescence imaging is one of the most attractive imaging techniques for monitoring important biomolecules in the biomedical field due to its advantages of low light scattering, high penetration depth, and suppressed photodamage/phototoxicity under near-infrared excitation. However, in actual biological imaging, organic two-photon fluorescent dyes have disadvantages such as high biological toxicity and their fluorescence efficiency is easily affected by the complex environment in organisms. In this study, a novel nanoprobe platform with two-photon dye-doped silica nanoparticles was developed for FRET-based ratiometric biosensing and bioimaging, with endogenous ATP chosen as the target for detection. The nanoprobe has three components: (1) a two-photon dye-doped silica nanoparticle core, which serves as an energy donor for FRET; (2) amino-modified hairpin primers with carboxy fluorescein as an energy acceptor for FRET; (3) an aptamer acting as a recognition unit to realize the probing function. The nanoprobe showed ratiometric fluorescence responses for ATP detection with high sensitivity and high selectivity in vivo. Moreover, the nanoprobe showed satisfactory ratiometric two-photon fluorescence imaging of endogenous ATP in living cells and tissues (penetration depth of 190 nm). These results indicated that novel two-photon silica nanoparticles can be constructed by doping a two-photon fluorescent dye into silica nanoparticles, and they can effectively solve the disadvantages of two-photon fluorescent dyes. These excellent performances indicate that this novel nanoprobe platform will become a very valuable molecular imaging tool, which can be widely used in the biomedical field for drug screening and disease diagnosis and other related research.

Multicolor Two-Photon Nanosystem for Multiplexed Intracellular Imaging and Targeted Cancer Therapy.

The novel theranostic nanosystems based on two-photon fluorescence can achieve higher spatial resolution of deep tissue imaging for simultaneous diagnosis and therapy of a variety of cancers. Herein, we have designed and prepared FRET-based two-photon mesoporous silica nanoparticles (MTP-MSNs) for single-excitation multiplexed intracellular imaging and targeted cancer therapy for the first time. This nanosystem includes two constituents, containing (1) multicolor two-photon mesoporous silica nanoparticles and (2) cancer cell-targeting aptamers that act as gatekeepers for MTP-MSNs. After incubation with cancer cells, the Dox-loaded and aptamer-capped MTP-MSNs could be internalized into the cells, opening the pores and releasing the drug. Furthermore, using two-photon multicolor fluorescence, MTP-MSNs could serve as good contrast agents for multicolor two-photon intracellular imaging with increased imaging depth and improved spatial localization of tissue. In sum, these multicolor MTP-MSNs provide a promising system for traceable targeted cancer therapy with further applications in multiplex intracellular imaging and the screening of drug.

Oxygen Vacancy-Driven Reversible Free Radical Catalysis for Environment-Adaptive Cancer Chemodynamic Therapy.

Amplifying free radical production by chemical dynamic catalysis to cause oxidative damage to cancer cells has received extensive interest for cancer-specific therapy. The major challenge is inevitable negative modulation on the tumor microenvironment (TME) by these species, hindering durable effectiveness. Here we show for the first time an oxygen vacancy-rich Bi-based regulator that allows environment-adaptive free radical catalysis. Specifically, the regulator catalyzes production of highly toxic O2.- and . OH in cancer cells via logic enzymatic reactions yet scavenges accumulation of free radicals and immunosuppressive mediators in TME-associated noncancerous cells. Atomic-level mechanistic studies reveal that such dual-modal regulating behavior is dominated by oxygen vacancies that well fit for free radical catalytic kinetics, along with distinguished cellular fates of this regulator. With this smart regulator, a "two birds with one shot" cancer dynamic therapy can be expected.

Decoding the Complex Free Radical Cascade by Using a DNA Framework-Based Artificial DNA Encoder.

DNA-based molecular communications (DMC) are critical for regulating biological networks to maintain stable organismic functions. However, the complicated, time-consuming information transmission process involved in genome-coded DMC and the limited, vulnerable decoding activity generally lead to communication impairment or failure, in response to external stimuli. Herein, we present a conceptually innovative DMC strategy mediated by the DNA framework-based artificial DNA encoder. With the free-radical cascade as a proof-of-concept study, the artificial DNA encoder shows active sensing and real-time actuation, in situ and broad free radical-decoding efficacy, as well as robust resistance to environmental noise. It can also block undesirable short-to-medium-range communications between free radicals and inflammatory networks, leading to a synergistic anti-obesity effect. The artificial DNA encoder-based DMC may be generalized to other communication systems for a variety of applications.

Conjugating Aptamer and Mitomycin C with Reductant-Responsive Linker Leading to Synergistically Enhanced Anticancer Effect.

Mitomycin C (MMC) has been using for the treatment of a variety of digestive tract cancers. However, its nonspecific DNA-alkylating ability usually causes severe side effects, thus largely limiting its clinical applications. The utilization of an efficient active targeted drug delivery technique would address this issue. Accordingly, we report the design and development of aptamer-mitomycin C conjugates that use different cross-linking chemistry. The targeted delivery ability and cytotoxicity of these conjugates were carefully studied. It is worth noting that a linker-dependent cytotoxicity effect was observed for these conjugates. The use of a reductant-sensitive disulfide bond cross-linking strategy resulted in significantly enhanced cytotoxicity of MMC against the target cancer cell lines. Importantly, this cytotoxicity enhancement was suited to different types of aptamers, demonstrating the success of our design. Mechanistic studies of the enhanced cytotoxicity effect indicated that the target recognition, specific binding, and receptor-mediated internalization of aptamer were also critical for the observed effect.

Transducing Complex Biomolecular Interactions by Temperature-Output Artificial DNA Signaling Networks.

The requirement of special expensive instruments for quantitative information readout has significantly restricted sustainable development, from ideation to execution, of advanced artificial networks. Here we present a step toward a paradigm of evolutionary signaling networks that enable translating complex signaling information into easy-to-read temperature output. Combining DNA molecular engineering with basic optical mechanisms, a DNA/Hemin complex-derived versatile temperature-output transducer is established, which can be coupled with other functional modules to fabricate diverse portable DNA signaling networks by dynamic programming of DNA chemical reactions. Its versatility is successfully demonstrated by constructing self-amplified and logic-circuit-based DNA signaling networks to monitor trace and multibit nucleic acid interactions using a thermometer. This affordable yet powerful DNA signaling network design may portend an era of point-of-care signaling network methodology.

Naked-Eye Readout of Analyte-Induced NIR Fluorescence Responses by an Initiation-Input-Transduction Nanoplatform.

Fluorescence visualization (FV) in the near-infrared (NIR) window promises to break through the signal-to-background ratio (SBR) bottleneck of traditional visible-light-driven FV methods. However, straightforward NIR-FV has not been realized, owing to the lack of methods to readily transduce NIR responses into instrument-free, naked eye-recognizable outputs. Now, an initiation-input-transduction platform comprising a well-designed NIR fluorophore as the signal initiator and lanthanide-doped nanocrystals as the transducer for facile NIR-FV is presented. The analyte-induced off-on NIR signal serves as a sensitizing switch of transducer visible luminescence for naked-eye readout. The design is demonstrated for portable, quantitative detection of phosgene with significantly improved SBR and sensitivity. By further exploration of initiators, this strategy holds promise to create advanced NIR-FV probes for broad sensing applications.

Near Infrared Graphene Quantum Dots-Based Two-Photon Nanoprobe for Direct Bioimaging of Endogenous Ascorbic Acid in Living Cells.

Ascorbic acid (AA), as one of the most important vitamins, participates in various physiological reactions in the human body and is implicated with many diseases. Therefore, the development of effective methods for monitoring the AA level in living systems is of great significance. Up to date, various technologies have been developed for the detection of AA. However, few methods can realize the direct detection of endogenous AA in living cells. In this work, we for the first time reported that near-infrared (NIR) graphene quantum dots (GQD) possessed good two-photon fluorescence properties with a NIR emission at 660 nm upon exciting with 810 nm femtosecond pulses and a two-photon (TP) excitation action cross-section (δΦ) of 25.12 GM. They were then employed to construct a TP nanoprobe for detection and bioimaging of endogenous AA in living cells. In this nanosystem, NIR GQDs (NGs), which exhibited lower fluorescence background in living system to afford improved fluorescence imaging resolution, were acted as fluorescence reporters. Also CoOOH nanoflakes were chosen as fluorescence quenchers by forming on the surface of NGs. Once AA was introduced, CoOOH was reduced to Co2+, which resulted in a "turn-on" fluorescence signal of NGs. The proposed nanoprobe demonstrated high sensitivity toward AA, with the observed LOD of 270 nM. It also showed high selectivity to AA with excellent photostability. Moreover, the nanoprobe was successfully used for TP imaging of endogenous AA in living cells as well as deep tissue imaging.