Photodynamic therapy (PDT), a therapeutic mode involving light triggering, has been recognized as an attractive oncotherapy treatment. However, nonnegligible challenges remain for its further ...clinical use, including finite tumor suppression, poor tumor targeting, and limited therapeutic depth. The photosensitizer (PS), being the most important element of PDT, plays a decisive role in PDT treatment. This review summarizes recent progress made in the development of PSs for overcoming the above challenges. This progress has included PSs developed to display enhanced tolerance of the tumor microenvironment, improved tumor-specific selectivity, and feasibility of use in deep tissue. Based on their molecular photophysical properties and design directions, the PSs are classified by parent structures, which are discussed in detail from the molecular design to application. Finally, a brief summary of current strategies for designing PSs and future perspectives are also presented. We expect the information provided in this review to spur the further design of PSs and the clinical development of PDT-mediated cancer treatments.
Molecular design directions for overcoming the photodynamic therapy challenges.
This tutorial review presents some recent developments in the construction and applications of cassettes based on resonance energy transfer between fluorescent dyes in the visible and infrared ...region. We focused on the contributions of different connections between the energy donor and acceptor according to the "through-space" and "through-bond" methods, and emphasised their applications in ratiometric sensing for the detection of ions and small molecules.
This
tutorial review
pays attention to the construction and applications of energy transfer cassettes, and emphasises ratiometric sensing for the detection of ions and small molecules.
Conspectus Fluorescent probes have become powerful tools in detection, imaging and disease diagnosis due to their high sensitivity, specificity, fast response, and technical simplicity. In the last ...decades, researchers have made remarkable progress in developing signaling mechanisms to design fluorescent probes such as photoinduced electron transfer (PET), intramolecular charge transfer (ICT), and fluorescence resonance energy transfer (FRET). Typical PET is composed of a multicomponent system in which a fluorophore (electron acceptor) is separately linked with a recognition group (electron donor) via a short spacer. PET probes normally feature a low fluorescence background and significant fluorescence enhancement in response to targets. Recent research revealed that PET probes have also been used as theranostic agents, whose fluorescence and toxicity can be simultaneously activated by cancer-specific parameters. In this Account, we highlight the recent advances of rational design and applications of PET probes, focusing primarily on studies from our research group. For example, different from the case of the traditional single-atom electron donor (O, S, N, Se, Te, etc.) in typical PET, we used more a electron-rich pyrrole ring to “switch off” the fluorescence of the fluorophore more efficiently through an “enhanced PET” effect which provided a lower background fluorescence and higher signal-to-noise ratio. Furthermore, normal PET represents the main principle behind the design of small molecule “off–on” fluorescent sensors. We developed new PET platform through intramolecular space folding (folding PET) to overcome the difficulty of designing PET enzyme-targeting probes. Therefore, based on typical PET and these new PET concepts, we, for instance, reported PET probes for the detection of Zn2+ without proton interference, a BODIPY-based d-PET probe for reporting local hydrophilicity within lysosomes, and an “enhanced PET” fluorescent probe for imaging HClO in cancer cells. We also developed COX-2-specific probe for identifying cancer cells and quantifying cancer-related events, and a KIAA1363-sensitive probe for tracking solid tumors in living mice. Furthermore, we first applied an aminopeptidase N (APN)-sensitive probe based on PET for cancer diagnosis and therapy. We anticipate that further development of PET fluorescent probes providing more sensitivity and selectivity to analytes of interest will be equipped with more functions and play indispensable roles in the studies of pathology, diagnostics, and cancer therapies.
Carbon dots (CDs), a kind of carbon material discovered accidentally, exhibit unexpected advantages in fluorescence imaging/sensing such as photostability, biocompatibility, and low toxicity. For ...emerging theranostics, an interdiscipline created by integrating therapy and diagnostics, CDs are good candidates when they are combined with targeted chemo/gene/photodynamic/photothermal therapeutic moieties. Here, the development of CDs in nanomedicine is reviewed from their use as original imaging agents and/or drug carriers to multifunctional theranostic systems. Finally, the challenges and prospects of the next‐generation of CD‐based theranostics for clinical applications are also discussed.
Carbon dots (CDs) in nanomedicine are gradually developed from original imaging agents and/or drug carriers to smart multifunctional theranostic systems. In addition to having the common advantages of stability, biocompatibility, and low toxicity, CDs with special photothermal therapy/ photodynamic therapy capability are successfully exploited. This work addresses recent encouraging progress in the development of CD‐based multifunctional nanomedicinal agents in theranostics.
Transition metals (d-blocks) are recognized as playing critical roles in biology, and they most often act as cofactors in diverse enzymes; however, improper regulation of transition metal stores is ...also connected to serious disorders. Therefore, the monitoring and imaging of transition metals are significant for biological research as well as clinical diagnosis. In this article, efforts have been made to review the chemical sensors that have been developed for the detection of the first-row d-block metals (except Cu and Zn): Cr, Mn, Fe, Co, and Ni. We focus on the development of fluorescent sensors (fall into three classes: "turn-off", "turn-on", and ratiometric), colorimetric sensors, and responsive MRI contrast agents for these transition metals (242 references). Future work will be likely to fill in the blanks: (1) sensors for Sc, Ti, and V; (2) MRI sensors for Cr, Mn, Co, Ni; (3) ratiometric fluorescent sensors for Cr
6+
, Mn
2+
, and Ni
2+
, explore new ways of sensing Fe
3+
or Cr
3+
without the proton interference, as well as extend applications of MRI sensors to living systems.
This critical review focuses on the development of fluorescent sensors (fall into three classes: "turn-off", "turn-on", and ratiometric), colorimetric sensors, and responsive MRI contrast agents for the first-row d-block metals (except Cu and Zn): Cr, Mn, Fe, Co, and Ni (242 references).
Endogenous gaseous signaling molecules including nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H
2
S) have been demonstrated to perform significant physiological and pharmacological ...functions and are associated with various diseases in biological systems. In order to obtain a deeper insight into their roles and mechanisms of action, it is desirable to develop novel techniques for effectively detecting gaseous signaling molecules. Small-molecule fluorescent probes have been proven to be a powerful approach for the detection and imaging of biological messengers by virtue of their non-invasiveness, high selectivity, and real-time
in situ
detection capability. Based on the intrinsic properties of gaseous signaling molecules, numerous fluorescent probes have been constructed to satisfy various demands. In this perspective, we summarize the recent advances in the field of fluorescent probes for the detection of NO, CO and H
2
S and illustrate the design strategies and application examples of these probes. Moreover, we also emphasize the challenges and development directions of gasotransmitter-responsive fluorescent probes, hoping to provide a general implication for future research.
This perspective article aims to introduce the design principles and recognition strategies of small-molecule fluorescent probes which are applied for the detection of gas signaling molecules including NO, CO and H
2
S in biological systems.
Chemiluminescence, the generation of light through chemiexcitation as a result of chemical reactions, has emerged as a novel tool for bioimaging and therapy
in vivo
. Due to the elimination of ...external optical excitation, it can effectively avoid background autofluorescence existing in fluorescence techniques, providing extremely high signal-to-noise ratios and sensitivity in bioimaging. Furthermore,
in situ
emitted photons can replace traditional excitation light to construct chemiexcited photodynamic therapy or drug release systems for the monitoring and treatment of deeply seated diseases or tumors. In this tutorial review, we will focus on the recent advancements of chemiluminescent platforms based on luminophore substrates including luminol and its derivatives, cypridina luciferin analogs, peroxyoxalates, and dioxetanes, and systematically summarize the design principles, sensing mechanisms, and bioimaging and therapeutic applications of representative chemiluminescent probes as well as theranostic agents. Finally, the potential challenges and perspectives of chemiluminescent platforms for bioimaging and therapeutics are also discussed.
The current progress, design principles in bioimaging and therapeutic applications, and future perspectives of various chemiluminescent platforms are reviewed.
Mild chemical processes of various analytes and detection methods involving revolutionary strategies in the fields of analytical chemistry, biology and environmental sciences have been extensively ...developed. This
critical review
focuses on representative examples of mild chemical processes that can be used in fluorescent chemodosimeters for ion sensing (anions and cations). A systematisation according to the type of reaction mechanism is established. Numerous examples including extensions combined with catalytic and material sciences applicable in fluorescence imaging and water treatment are also discussed (151 references).
This
critical review
focuses on advances in various mild chemical processes that can form the basis of fluorescent chemodosimeters for anions and cations, as well as catalytic and material science application in fluorescence imaging and water treatment.
As traditional phototherapy agents, boron dipyrromethene (BODIPY) photosensitizers have attracted increasing attention due to their high molar extinction coefficients, high phototherapy efficacy, and ...excellent photostability. After being formed into nanostructures, BODIPY‐containing nano‐photosensitizers show enhanced water solubility and biocompatibility as well as efficient tumor accumulation compared to BODIPY molecules. Hence, BODIPY nano‐photosensitizers demonstrate a promising potential for fighting cancer. This review contains three sections, classifying photodynamic therapy (PDT), photothermal therapy (PTT), and the combination of PDT and PTT based on BODIPY nano‐photosensitizers. It summarizes various BODIPY nano‐photosensitizers, which are prepared via different approaches including molecular precipitation, supramolecular interactions, and polymer encapsulation. In each section, the design strategies and working principles of these BODIPY nano‐photosensitizers are highlighted. In addition, the detailed in vitro and in vivo applications of these recently developed nano‐photosensitizers are discussed together with future challenges in this field, highlighting the potential of these promising nanoagents for new tumor phototherapies.
Boron dipyrromethene (BODIPY) nano‐photosensitizers are equipped with enhanced water solubility, biocompatibility, and tumor accumulation via the enhanced permeability and retention (EPR) effect. In addition, their excellent photostability and large molar extinction coefficient in the near infrared (NIR) region ensure a special phototherapy effect toward tumors. This review focuses on the design and preparation of BODIPY containing nano‐photosensitizers for anticancer phototherapy.
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