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Many important biological species have been identified as cancer biomarkers and are gradually becoming reliable targets for early diagnosis and late therapeutic evaluation of cancer. However, accurate quantitative detection of cancer biomarkers remains challenging due to the complexity of biological systems and the diversity of cancer development. Fluorescent probes have been extensively utilized for identifying biological substances due to their notable benefits of being non-invasive, quickly responsive, highly sensitive and selective, allowing real-time visualization, and easily modifiable. This review critiques fluorescent probes used for detecting and imaging cancer biomarkers over the last five years. Focuses are made on the design strategies of small-molecule and nano-sized fluorescent probes, the construction methods of fluorescence sensing and imaging platforms, and their further applications in detection of multiple biomarkers, including enzymes, reactive oxygen species, reactive sulfur species, and microenvironments. This review aims to guide the design and development of excellent cancer diagnostic fluorescent probes, and promote the broad application of fluorescence analysis in early cancer diagnosis. [ABSTRACT FROM AUTHOR]

Monoaromatic molecules are a category of molecules containing a single aromatic ring which generally emit light in the ultraviolet (UV) region. Despite their facile preparation, the UV emission greatly limits their application as organic probes. In this study, we developed a general method to red shift the emission of monoaromatic molecules. Significant fluorescence red-shift (∼100 nm per intramolecular hydrogen bonding) can be achieved by introducing intramolecular hydrogen bonding units to benzene, a typical monoaromatic molecule. Upon increasing the number of hydrogen bonding units on the benzene ring, UV, blue, and green emissions are screened, which are switchable by simply breaking/restoration the intramolecular hydrogen bonding. As a demonstration, with the breaking of one intramolecular H-bonding, the green emission (λ em max = 533 nm) of 2,5-dihydroxyterephthalic acid (DHTA) changed to cyan (λ em max = 463 nm) upon the formation of its phosphorylated form (denoted as PDHTA), which, in the presence of alkaline phosphatase (ALP), hydrolyzed and recovered the green emission. By taking advantage of the switchable emission colors, ratiometric in vitro and endogenous ALP sensing was achieved. This general approach offers a great promise to develop organic probes with tunable emissions for fluorescence analysis and imaging by different intramolecular hydrogen bonding. Image 1 • Intramolecular hydrogen bonding-induced large red emission-shift of monoaromatics was presented. • Ratiometric fluorescence variation of monoaromatics by altering intramolecular hydrogen bonding was realized. • A sensitive and selective ratiometric fluorescence probe for evaluating alkaline phosphatase activity was proposed. • The visualization of endogenous alkaline phosphatase was achieved. [ABSTRACT FROM AUTHOR]

Plasmonic nanoparticles with special localized surface plasmon resonance (LSPR) characters have been widely applied for optical sensing of various targets. With the combination of single nanoparticle imaging techniques, dynamic information of reactions and biological processes is obtained, facilitating the deep understanding of their principle and design of outstanding nanomaterials. In this review, we summarize the recently adopted optical analysis of diverse analytes based on plasmonic nanoparticles both in homogeneous solution and at the single-nanoparticle level. A brief introduction of LSPR is first discussed. Colorimetric and fluorimetric homogeneous detection examples by using different sensing mechanisms and strategies are provided. Single plasmonic nanoparticle-based analysis is concluded in two aspects: visualization of chemical reactions and understanding of biological processes. The basic sensing mechanisms and performances of these systems are introduced. Finally, this review highlights the challenges and future trend of plasmonic nanoparticle-based optical analysis systems. [ABSTRACT FROM AUTHOR]

With the rapid development of nanotechnology, strategies related to nanomedicine have been used to overcome the shortcomings of traditional chemotherapy drugs, thereby demonstrating significant potential for innovative drug delivery. Nanomaterials play an increasingly important role in cancer immunotherapy. Stimuli-responsive nanomaterials enable the precise control of drug release through exposure to specific stimuli and exhibit excellent specificity in response to various stimuli. Immunomodulators carried by nanomaterials can also effectively regulate the immune system and significantly improve their therapeutic effect on cancer. In recent years, stimuli-responsive nanomaterials have evolved rapidly from single stimuli-responsive systems to multi-stimuli-responsive systems. This review focuses on recent advances in the design and applications of stimuli-responsive nanomaterials, including exogenous and endogenous responsive nanoscale drug delivery systems, which show extraordinary potential in intelligent drug delivery for multimodal cancer diagnosis and treatment. Ultimately, the opportunities and challenges in the development of intelligent responsive nanomaterials are briefly discussed according to recent advances in multi-stimuli-responsive systems. [Display omitted] [ABSTRACT FROM AUTHOR]

The rapid and sensitive visualization of 2,6-dipicolinic acid (DPA, a unique anthrax biomarker) is essential to prevent anthrax disease or biological terrorist attack. In this study, a Eu3+-labeled ethylenediaminetetraacetic acid loaded hyperbranched polyethyleneimine carbon nanodot (hPEI-CD-EDTA-Eu3+) nanoprobe has been proposed for the ratiometric DPA detection. The sensing mechanism is based on the rapid DPA-Eu3+ chelation within 30 s and subsequent enhanced fluorescence emission through the antenna effect. With the introduction of EDTA chelating unit, the resulted fluorescence of Eu3+-complex is greatly enhanced, which endows sensitive DPA perception. By employing hPEI-CD as the internal reference, ratiometric DPA sensing is realized with a good linearity in the concentration range from 1.0 to 100 nM, with a limit of detection of 190 pM (S/N = 3). The specific chelation affinity between Eu3+ and DPA provides satisfying selectivity over other amino acids and ions. Using nanoprobe-loaded polyvinylidene fluoride paper as the analytical device, point-of-care DPA visualization is achieved. Furthermore, the practical application of designed paper device is validated by the visual detection of metabolic DPA-release from Bacillus subtilis spores. Image 1 • EDTA chelation can greatly enhance the fluorescence of Eu3+‒DPA complex. • Eu3+-labeled carbon nanodot fluorescence nanoprobe for sensitive DPA detection was fabricated. • Other metal ions or amino acids had no interference on DPA sensing. • The point-of-care DPA detection was achieved using nanoprobe-loaded PVDF paper device. • The visualization of metabolic DPA-release from Bacillus subtilis spores was realized. [ABSTRACT FROM AUTHOR]