Fluorescent Probes for Imaging in Humans: Where Are We Now?

Squaraine-Peptide Conjugates as Efficient Reporters of Neutrophil Extracellular Traps-Mediated Chronic Inflammation

The excessive and uncontrolled release of neutrophil extracellular traps (NETs) is increasingly linked to the pathogenesis of various inflammatory diseases, cardiovascular disorders, and cancers. Real-time, non-invasive detection of NETs is crucial for understanding their role in disease progression and developing targeted therapies. Current NETs detection methods often lack the necessary specificity and resolution, particularly in vivo and ex vivo settings. To address this, we have developed novel near-infrared squaraine-peptide conjugates by rational molecular design as reporters of NETosis by targeting the protease activity of neutrophil elastase (NE). These self-quenching, cell-impermeable probes enable the precise real-time detection and imaging of NETs. The Förster resonance energy transfer (FRET)-based probe, Hetero-APA, demonstrated high specificity in detecting NETs in vitro and in vivo, generating strong fluorescence in NETs-rich environments. To overcome the limitations of FRET-based probes for ex vivo imaging, we designed SQ-215-NETP, a non-FRET-based probe that covalently binds to the NE. SQ-215-NETP achieved an unprecedented imaging resolution of 90 nm/pixel in human coronary thrombi, marking the first report of such high resolution with a low molecular weight probe. Additionally, SQ-215-NETP effectively detected NETs by flow cytometry. These results highlight the potential of these probes in NETosis detection, offering promising tools for enhanced diagnostics and therapeutic strategies in managing NET-mediated inflammatory diseases and cancers.

Tumor agnostic ultrasmall nanoprobes for fluorescence-guided surgical resection in peritoneal metastasis

PURPOSE

Surgical excision of metastases is the only curative treatment strategy in peritoneal carcinomatosis management, and the completeness of tumor resection determines the success of the surgery. Tumor-specific fluorescence-guided probes can improve the outcomes of cytoreductive surgery and thereby prognosis. This study aimed to develop and evaluate the feasibility of fluorescently labeled ultrasmall porous silica nanoparticles (UPSN) for image-guided resection of peritoneally disseminated tumors of different origins.

METHODS

Ultrasmall fluorescent nanoprobes were synthesized and characterized for their physicochemical properties and stability. Tumor-specific uptake and biodistribution profiles were evaluated in syngeneic CT26 colorectal and KPC-689 pancreatic cancer murine models. The practicability of real-time optical UPSN-guided resection was examined in the CT26 colorectal cancer model using a surgical stereomicroscope. Quantitative measurements of tumor sensitivity and specificity were performed. Histopathological examination validated in vivo findings about tumor-specific accumulation and safety of ultrasmall fluorescent probes.

RESULTS

As-synthesized UPSNs were successfully surface modified with Cy5 or Cy3 dyes maintaining sub-15 nm size and near neutral charge which is beneficial for optimized in vivo pharmacokinetics. UPSN-Cy5 demonstrated high tumor-specific uptake and favorable biodistribution profiles in peritoneal metastasis models of CT26 and KPC tumors. Dye-conjugated UPSN enabled resection of microscopic lesions and achieved a higher tumor-to-background ratios in comparison to FDA-approved indocyanine green (ICG) dye in both models. Microscopic evaluation showed tumor localization and off-target safety profile of the UPSN-Cy5.

CONCLUSION

Ultrasmall fluorescent probes were effective in surgical resection of peritoneal metastases with high sensitivity and specificity, thus emerging as promising tumor agnostic agents for image-guided cancer surgery.

High Spatiotemporal Near-Infrared II Fluorescence Lifetime Imaging for Quantitative Detection of Clinical Tumor Margins

Accurate detection of tumor margins is essential for successful cancer surgery. While indocyanine green (ICG)-based near-infrared (NIR) fluorescence (FL) surgical navigation enhances the visual identification of tumor margins, its accuracy remains subjective, underscoring the need for quantitative approaches. In this study, a high spatiotemporal fluorescence lifetime (FLT) imaging technology is developed in the second near-infrared window (NIR-II, 1000-1700 nm) for quantitative tumor margin detection, utilizing folate receptor-targeted ICG nanoprobes (FPH-ICG). FPH-ICG exhibits a significantly prolonged NIR-II FLT (750 ± 7 ps vs 260 ± 3 ps) and increased NIR-II FL brightness (FPH-ICG/ICG = 3.8). In vitro and in vivo studies confirm that FPH-ICG specifically targets folate receptor-α (FRα) on SK-OV-3 ovarian cancer cells, achieving high-contrast NIR-II FL imaging with a signal-to-background ratio of 10.8. Notably, NIR-II FLT imaging demonstrates superior accuracy (90%) and consistency in defining tumor margins compared to NIR-II FL imaging (58%) in both SK-OV-3 tumor-bearing mice and clinical tumor samples. These findings underscore the potential of NIR-II FLT imaging as a quantitative tool for guiding surgical tumor margin detection.

Rigid, α-Helical Polypeptide Nanoprobes with Thermally Activated Delayed Fluorescence for Time-Resolved, High-Contrast Bioimaging

Thermally activated delayed fluorescence (TADF)-based nanoprobes are promising candidates as bioimaging agents, yet the fine-tuning of their photophysical properties through the modulation of the surrounding matrices remains largely unexplored. Herein, we report the development of polypeptide-TADF nanoprobes, where the rigid, α-helical polypeptide scaffold plays a critical role in enhancing the emission intensity and lifetime of the TADF fluorophore for bioimaging. The α-helical scaffolds not only spatially separated TADF molecules to avoid self-quenching but also anchored the dyes with minimized rotation and vibration. The nanoprobes thus exhibited >600 nm microsecond emission even in the presence of oxygen, facilitating cellular and animal imaging with a high signal-to-background ratio (SBR) by minimizing the interferences from autofluorescence signals. We believe that this work highlights the impact of the supporting polymeric conformation on the TADF performance, offering insights for the future design of time-resolved imaging probes.

Aggregation-Induced Emission Luminogens Realizing High-Contrast Bioimaging

A revolutionary transformation in biomedical imaging is unfolding with the advent of aggregation-induced emission luminogens (AIEgens). These cutting-edge molecules not only overcome the limitations of traditional fluorescent probes but also improve the boundaries of high-contrast imaging. Unlike conventional fluorophores suffering from aggregation-caused quenching, AIEgens exhibit enhanced luminescence when aggregated, enabling superior imaging performance. This review delves into the molecular mechanisms of aggregation-induced emission (AIE), demonstrating how strategic molecular design unlocks exceptional luminescence and superior imaging contrast, which is crucial for distinguishing healthy and diseased tissues. This review also highlights key applications of AIEgens, such as time-resolved imaging, second near-infrared window (NIR-II), and the advancement of AIEgens in sensitivity to physical and biochemical cue-responsive imaging. The development of AIE technology promises to transform healthcare from early disease detection to targeted therapies, potentially reshaping personalized medicine. This paradigm shift in biophotonics offers efficient tools to decode the complexities of biological systems at the molecular level, bringing us closer to a future where the invisible becomes visible and the incurable becomes treatable.

N-Bridged BODIPY Dimers: Exploring the Electron-Rich and Electron-Poor Coupling Limit via Pyrrole and Pyridine Annulation

A facile access to N-heteroaryl-fused bis-BODIPY scaffolds has been developed. A BODIPY dimer with an α,α-amine linker serves as a starting material to obtain pyrrole- and pyridine-fused BODIPYs, either by direct oxidation or by oxidative condensation with an aldehyde building block. Both species mark antipodal conjugative coupling conditions that result in distinct spectral outcomes. In stark contrast to the pyrrole fusion, pyridine-coupled species show unique panchromatic absorption profiles.

Smart molecular designs and applications of activatable organic photosensitizers

Photodynamic therapy (PDT) - which combines light, oxygen and photosensitizers (PS) to generate reactive oxygen species - has emerged as an effective approach for targeted ablation of pathogenic cells with reduced risk of inducing resistance. Some organic PS are now being applied for PDT in the clinic or undergoing evaluation in clinical trials. A limitation of the first-generation organic PS was their potential off-target toxicity. This shortcoming prompted the design of constructs that can be activated by the presence of specific biomolecules - from small biomolecules to large enzymes - in the target cells. Here, we review advances in the design and synthesis of activatable organic PS and their contribution to PDT in the past decade. Important areas of research include novel synthetic methodologies to engineer smart PS with tuneable singlet oxygen generation, their integration into larger constructs such as bioconjugates, and finally, representative examples of their translational potential as antimicrobial and anticancer therapies.

Review of Clinically Assessed Molecular Fluorophores for Intraoperative Image Guided Surgery

The term "fluorescence" was first proposed nearly two centuries ago, yet its application in clinical medicine has a relatively brief history coming to the fore in the past decade. Nowadays, as fluorescence is gradually expanding into more medical applications, fluorescence image-guided surgery has become the new arena for this technology. It allows surgical teams to real-time visualize target tissues or anatomies intraoperatively to increase the precision of resection or preserve vital structures during open or laparoscopic surgeries. In this review, we introduce the concept of near-infrared fluorescence guided surgery, discuss the recent and ongoing clinical trials of molecular fluorophores (indocyanine green, 5-aminolevulinic acid, methylene blue, IR-dye 800CW, pafolacianine) and their surgical goals, highlight key chemical and medical factors for imaging agent optimization, deliberate challenges and potential advantages, and propose a framework for integrating this technology into routine surgical care in the near future. The notable clinical achievements of these fluorophores over the past decade strongly indicates that the future of fluorescence in surgery is bright with many more patient benefits to come.

Nano-fluorescence imaging: advancing lymphatic disease diagnosis and monitoring

The lymphatic system plays a crucial role in maintaining physiological homeostasis and regulating immune responses. Traditional imaging modalities such as magnetic resonance imaging, computerized tomography, and positron emission tomography have been widely used to diagnose disorders in the lymphatic system, including lymphedema, lymphangioma, lymphatic metastasis, and Castleman disease. Nano-fluorescence technology has distinct advantages-including naked-eye visibility, operational simplicity, portability of the laser, and real-time visibility-and serves as an innovative alternative to traditional imaging techniques. This review explores recent advancements in nano-fluorescence imaging aimed at enhancing the resolution of lymphatic structure, function, and immunity. After delineating the fundamental characteristics of lymphatic systems, it elaborates on the development of various nano-fluorescence systems (including nanoparticles incorporating fluorescent dyes and those with intrinsic fluorescence) while addressing key challenges such as photobleaching, limited tissue penetration, biocompatibility, and signal interference from biomolecules. Furthermore, this review highlights the clinical applications of nano-fluorescence and its potential integration into standard diagnostic protocols. Ongoing advancements in nanoparticle technology underscore the potential of nano-fluorescence to revolutionize the diagnosis and treatment of lymphatic disease.

Advancing the Validation of the Enrichment-Enhanced Detection Strategy with Au Nanoclusters for AChE Detection

High-sensitivity fluorescent probes provide a powerful tool for understanding life processes and functioning mechanisms. Therefore, the development of a universal strategy to optimize probes holds substantial importance. Herein, we developed a novel strategy for common probe upgrades: rather than simply pursuing a higher fluorescence intensity of the probe itself, we tried to promote the detection sensitivity by enhancing the probe-substrate interactions. Fortified with polyionic polymers, self-assembled probes could be endowed with enhanced attractions to the substrate. In this work, we took the AChE-AuNCs detection system as a typical and important example to verify this concept of the "enrichment-enhanced detection" strategy (EED strategy). Two probes, AuNCs@GC and AuNCs@CMCS, with similar composing polymers (chitosan derivatives), microstructures, fluorescence profiles, and distinct charges were delicately designed and thoroughly studied. CMCS with an abundance of negatively charged carboxy groups plays an important role in the enrichment of thiocholine through electrostatic interactions. Thus, despite having similar composing components, structures, and almost identical fluorescence profiles, the negatively charged composite shows superior sensitivity (15.2-fold enhancement) and response time (2-fold faster) compared to the AuNCs@GC, thereby validating the feasibility of the EED strategy. Overall, our work validates the EED strategy and applies it to the accurate detection of AChE activity. We believe that this strategy offers substantial insights for the generalization and enhancement of advanced nanoprobes.

Realizing real-time optical molecular imaging in peripheral nerve tissue via Rhodamine B

Background

Iatrogenic nerve injury is a consequential complication during surgery. Thus, real-time imaging of peripheral nerve (PN) possesses significant clinical implications. In recent years, the rapid advancements in optical molecular imaging (OMI) technology have provided essential technical foundations for the implementation of PN fluorescence imaging. This study aimed to realize real-time OMI of PNs via Rhodamine B.

Methods

Phosphate buffered saline (PBS), normal saline (NS), 5% glucose solution (GS), and fetal bovine serum (FBS) were selected for measuring the fluorescence spectra of Rhodamine B solutions prepared in each formulation. Rhodamine B solutions, with varying doses dissolved in 100 μL of each formulation, were prepared and applied to the exposed PNs of the mice for incubation later. To ascertain the optimal formulation and dose of Rhodamine B, an analysis was performed on the signal-to-background ratio (SBR) of the nerves. Based on the experimental results, we proceeded to incubate Rhodamine B solution on the PN tissue of mice and human subjects, as well as on neuronal cells, to verify the binding sites of Rhodamine B with nerve. Subsequently, histological studies were conducted to validate the binding site between Rhodamine B and the nerves. Finally, we injected the optimal combination of Rhodamine B solution into mice via the tail vein and collected the SBR of mouse nerve tissues at different time intervals to determine the optimal pre-injection time. Fluorescence images of various tissues were collected, and Hematoxylin and Eosin (H&E) staining results were observed to determine the metabolism of Rhodamine B in mice and its toxicity.

Results

The excitation peak of Rhodamine B in PBS, NS, 5% GS, and FBS formulations was 554 nm, and the emission peak was 576 nm. In PBS group, the maximum SBR was 15.37 ± 0.68 while the dose of Rhodamine B was 8 nmol. Through ex-vivo validation on fresh human nerve tissue and verification using mouse and human tissue sections, we observed fluorescent signals of Rhodamine Bin the regions of nerve tissue and the fluorescence signals were all concentrated on the neuronal cell membranes. After injection, the fluorescent signal in nerve tissue reached its peak at 24 hours (h), coinciding with the highest SBR (5.93 ± 0.92) in mouse nerve tissues at this time point. Additionally, the fluorescence signal could be maintained for at least 48 h. Within 24 h, lung dilation and fusion of alveoli occurred. Then these pathological manifestations gradually diminished, returning to normal at 2 weeks (w), with no significant acute or chronic adverse reactions observed in other tissues.

Conclusion

Rhodamine B enables fluorescence imaging of PNs and has the potential for clinical translation.

The Emerging Era of Molecular Medicine

The era of molecular medicine arose as we began to diagnose and treat diseases based on understanding how genes, proteins, and cells work, providing optimal therapeutic care through molecular profiling. Central to molecular medicine is molecular recognition, which is underpinned by techniques involving omics analysis, gene editing, and targeted agents. Recent advancements in these tools not only expand our understanding of biological processes but also aid in the development of diagnostic and treatment modalities at the molecular level, thus bridging the gap between medical research and clinical applications. This perspective traces the development of molecular tools, highlighting, along the way, their pivotal role in advancing molecular medicine for the global health of people.

Recent Advances in Degradable Biomedical Polymers for Prevention, Diagnosis and Treatment of Diseases

Biomedical polymers play a key role in preventing, diagnosing, and treating diseases, showcasing a wide range of applications. Their unique advantages, such as rich source, good biocompatibility, and excellent modifiability, make them ideal biomaterials for drug delivery, biomedical imaging, and tissue engineering. However, conventional biomedical polymers suffer from poor degradation in vivo, increasing the risks of bioaccumulation and potential toxicity. To address these issues, degradable biomedical polymers can serve as an alternative strategy in biomedicine. Degradable biomedical polymers can efficiently relieve bioaccumulation in vivo and effectively reduce patient burden in disease management. This review comprehensively introduces the classification and properties of biomedical polymers and the recent research progress of degradable biomedical polymers in various diseases. Through an in-depth analysis of their classification, properties, and applications, we aim to provide strong guidance for promoting basic research and clinical translation of degradable biomedical polymers.

Targeting Human Pancreatic Cancer with a Fluorophore-Conjugated Mucin 4 (MUC4) Antibody: Initial Characterization in Orthotopic Cell Line Mouse Models

Background/Objectives: Pancreatic cancer is the third leading cause of death related to cancer. The only possible cure presently is complete surgical resection; however, this is limited by difficulty in clearly defining tumor margins. Enhancement of the visualization of pancreatic ductal adenocarcinoma (PDAC) tumor margins using near-infrared dye-conjugated tumor-specific antibodies was pioneered by using anti-CEA, anti-CA19.9, and anti-MUC5AC in orthotopic mouse models of pancreatic cancer. Recently, an antibody to Mucin 4 (MUC4) conjugated to a fluorescent probe has shown promise in targeting colon tumors in orthotopic mouse models. Methods: In the present study, we targeted pancreatic cancer using an anti-MUC4 antibody conjugated to IRDye800 (anti-MUC4-IR800) in orthotopic mouse models. Two pancreatic cancer human cell lines were used, SW1990 and CD18/HPAF. Results: Anti-MUC4-IR800 targeted the two pancreatic cancer cell line tumors in orthotopic mouse models with high tumor-to-pancreas ratios and high tumor-to-liver ratios, with greater targeting seen in SW1990. Conclusions: The present results suggest anti-MUC4-IR800's potential to be used in fluorescence-guided surgical resection of pancreatic cancer.

A high-performance organic fluorescent probe with aggregation-induced emission properties for long-term tumor monitoring

Near-infrared organic fluorescent probes have great need in biological sciences and medicine but most of them are still largely unable to meet demand. In this work, a delicate multipurpose organic fluorescent probe (DPPM-TPA) with aggregation-induced emission performances is designed and prepared by facile method to reflect fluorescence labeling, two-photon imaging, and long-term fluorescent tracking. Specifically, DPPM-TPA NPs was constructed from 4-(diphenylamino)phenylboronic acid and DPPM-Br by classical Suzuki coupling reaction and then coated with F127. Such nanoprobe possessed high stability in diverse medium under ambient temperatures, low cytotoxicity, and brilliant fluorescence performance. More importantly, DPPM-TPA NPs showed excellent two-photon imaging and extraordinary long-term fluorescence tracing capacity to malignant tumor, and it can last up to 9 days. These results indicated that DPPM-TPA NPs is expected to serve as a fluorescent probe for photodiagnostic and providing a new idea for the development of long-term fluorescent tracker.

Emissive Lipid Nanoparticles as Biophotonic Contrast Agent for Site-Selective Solid Tumor Imaging in Pre-Clinical Models

Small organic dye-based fluorescent agents are highly potent in solid tumor imaging but face challenges such as poor photostability, nonspecific distribution, low circulation, and weak tumor binding. Nanocarriers overcome these issues with better physicochemical and biological performance, particularly in cancer imaging. Among the various nanosized carriers, lipid formulations are clinically approved but yet to be designed as bright nanocontrast agents for solid tumor diagnosis without affecting surrounding tissues. Herein, indocyanine green (ICG) encapsulated targetable lipid nanoparticles (698 ICG/LNPs) as safe contrast agents (∼200 nm) have been developed and tested for solid tumor imaging and biodistribution. Our findings reveal that nanoprecipitation produces ICG-LNPs with a unique assembly, which contributes to their high brightness with improved quantum yield (3.5%) in aqueous media. The bright, optically stable (30 days) biophotonic agents demonstrate rapid accumulation (within 1 h) and prolonged retention (for up to 168 h) at the primary tumor site, with better signal intensity following a one-time dose administration (17.7 × 109 LNP per dose). Incorporated folic acid (735 folic acid/LNPs) helps in selective tumor binding and the specific biodistribution of intravenously injected nanoparticles without affecting healthy tissues. Designed targetable ICG-LNP (634 MESF) demonstrates high-contrast fluorescence and resolution from the tumor area as compared to the targetable ICG-liposomal nanoparticles (532 MESF). Various in vitro and in vivo findings reveal that the cancer diagnostic efficacy elicited by designed bright lipid nanoparticles are comparable to reported clinically accepted imaging agents. Thus, such LNPs hold translational potential for cancer diagnosis at an early stage.

Rational Design of Cyanine-Based Fluorogenic Dimers to Reduce Nonspecific Interactions with Albumin and Lipid Bilayers: Application to Highly Sensitive Imaging of GPCRs in Living Cells

Fluorogenic dimers with polarity-sensitive folding are powerful probes for live-cell bioimaging. They switch on their fluorescence only after interacting with their targets, thus leading to a high signal-to-noise ratio in wash-free bioimaging. We previously reported the first near-infrared fluorogenic dimers derived from cyanine 5.5 dyes for the optical detection of G protein-coupled receptors. Owing to their hydrophobic character, these dimers are prone to form nonspecific interactions with proteins such as albumin and with the lipid bilayer of the cell membrane resulting in a residual background fluorescence in complex biological media. Herein, we report the rational design of new fluorogenic dimers derived from cyanine 5. By modulating the chemical structure of the cyanine units, we discovered that the two asymmetric cyanine 5.25 dyes were able to form intramolecular H-aggregates and self-quenched in aqueous media. Moreover, the resulting original dimeric probes enabled a significant reduction of the nonspecific interactions with bovine serum albumin and lipid bilayers compared with the first generation of cyanine 5.5 dimers. Finally, the optimized asymmetric fluorogenic dimer was grafted to carbetocin for the specific imaging of the oxytocin receptor under no-wash conditions directly in cell culture media, notably improving the signal-to-background ratio compared with the previous generation of cyanine 5.5 dimers.

Polymer-Tethered Quenched Fluorescent Probes for Enhanced Imaging of Tumor-Associated Proteases

Fluorescence-based contrast agents enable real-time detection of solid tumors and their neovasculature, making them ideal for use in image-guided surgery. Several agents have entered late-stage clinical trials or secured FDA approval, suggesting they are likely to become the standard of care in cancer surgeries. One of the key parameters to optimize in contrast agents is molecular size, which dictates much of the pharmacokinetic and pharmacodynamic properties of the agent. Here, we describe the development of a class of protease-activated quenched fluorescent probes in which a N-(2-hydroxypropyl)methacrylamide copolymer is used as the primary scaffold. This copolymer core provides a high degree of probe modularity to generate structures that cannot be achieved with small molecules and peptide probes. We used a previously validated cathepsin substrate and evaluated the effects of length and type of linker, as well as the positioning of the fluorophore/quencher pair on the polymer core. We found that the polymeric probes could be optimized to achieve increased overall signal and tumor-to-background ratios compared to the reference small molecule probe. Our results also revealed multiple structure-activity relationship trends that can be used to design and optimize future optical imaging probes. Furthermore, they confirm that a hydrophilic polymer is an ideal scaffold for use in optical imaging contrast probes, allowing a highly modular design that enables efficient optimization to maximize probe accumulation and overall biodistribution properties.

Recent advances of biocompatible optical nanobiosensors in liquid biopsy: towards early non-invasive diagnosis

Liquid biopsy is a non-invasive diagnostic method that can reduce the risk of complications and offers exceptional benefits in the dynamic monitoring and acquisition of heterogeneous cell population information. Optical nanomaterials with excellent light absorption, luminescence, and photoelectrochemical properties have accelerated the development of liquid biopsy technologies. Owing to the unique size effect of optical nanomaterials, their improved optical properties enable them to exhibit good sensitivity and specificity for mitigating signal interference from various molecules in body fluids. Nanomaterials with biocompatible and optical sensing properties play a crucial role in advancing the maturity and diversification of liquid biopsy technologies. This article offers a comprehensive review of recent advanced liquid biopsy technologies that utilize novel biocompatible optical nanomaterials, including fluorescence, colorimetric, photoelectrochemical, and Raman broad-spectrum-based biosensors. We focused on liquid biopsy for the most significant early biomarkers in clinical medicine, and specifically reviewed reports on the effectiveness of optical nanosensing technology in the detection of real patient samples, which may provide basic evidence for the transition of optical nanosensing technology from engineering design to clinical practice. Furthermore, we introduced the integration of optical nanosensing-based liquid biopsy with modern devices, such as smartphones, to demonstrate the potential of the technology in portable clinical diagnosis.

Bora-Diaza-Indacene Based Fluorescent Probes for Simultaneous Visualisation of Lipid Droplets and Endoplasmic Reticulum

Organelle selective fluorescent probes, especially those capable of concurrent detection of specific organelles, are of benefit to the research community in delineating the interplay between various organelles and the impact of such interaction in maintaining cellular homeostasis and its disruption in the diseased state. Although very useful, such probes are synthetically challenging to design due to the stringent lipophilicity requirement posed by different organelles, and hence, the lack of such probes being reported so far. This work details the synthesis, photophysical properties, and cellular imaging studies of two bora-diaza-indacene based fluorescent probes that can specifically and simultaneously visualise lipid droplets and endoplasmic reticulum; two organelles suggested having close interactions and implicated in stress-induced cellular dysfunction and disease progression.

Fluorescent Probes for Disease Diagnosis

The identification and detection of disease-related biomarkers is essential for early clinical diagnosis, evaluating disease progression, and for the development of therapeutics. Possessing the advantages of high sensitivity and selectivity, fluorescent probes have become effective tools for monitoring disease-related active molecules at the cellular level and in vivo. In this review, we describe current fluorescent probes designed for the detection and quantification of key bioactive molecules associated with common diseases, such as organ damage, inflammation, cancers, cardiovascular diseases, and brain disorders. We emphasize the strategies behind the design of fluorescent probes capable of disease biomarker detection and diagnosis and cover some aspects of combined diagnostic/therapeutic strategies based on regulating disease-related molecules. This review concludes with a discussion of the challenges and outlook for fluorescent probes, highlighting future avenues of research that should enable these probes to achieve accurate detection and identification of disease-related biomarkers for biomedical research and clinical applications.

Synthesis and Characterization of Click Chemical Probes for Single-Cell Resolution Detection of Epichaperomes in Neurodegenerative Disorders

Neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD), represent debilitating conditions with complex, poorly understood pathologies. Epichaperomes, pathologic protein assemblies nucleated on key chaperones, have emerged as critical players in the molecular dysfunction underlying these disorders. In this study, we introduce the synthesis and characterization of clickable epichaperome probes, PU-TCO, positive control, and PU-NTCO, negative control. Through comprehensive in vitro assays and cell-based investigations, we establish the specificity of the PU-TCO probe for epichaperomes. Furthermore, we demonstrate the efficacy of PU-TCO in detecting epichaperomes in brain tissue with a cellular resolution, underscoring its potential as a valuable tool for dissecting single-cell responses in neurodegenerative diseases. This clickable probe is therefore poised to address a critical need in the field, offering unprecedented precision and versatility in studying epichaperomes and opening avenues for novel insights into their role in disease pathology.

Semiconducting polymer dots for multifunctional integrated nanomedicine carriers

The expansion applications of semiconducting polymer dots (Pdots) among optical nanomaterial field have long posed a challenge for researchers, promoting their intelligent application in multifunctional nano-imaging systems and integrated nanomedicine carriers for diagnosis and treatment. Despite notable progress, several inadequacies still persist in the field of Pdots, including the development of simplified near-infrared (NIR) optical nanoprobes, elucidation of their inherent biological behavior, and integration of information processing and nanotechnology into biomedical applications. This review aims to comprehensively elucidate the current status of Pdots as a classical nanophotonic material by discussing its advantages and limitations in terms of biocompatibility, adaptability to microenvironments in vivo, etc. Multifunctional integration and surface chemistry play crucial roles in realizing the intelligent application of Pdots. Information visualization based on their optical and physicochemical properties is pivotal for achieving detection, sensing, and labeling probes. Therefore, we have refined the underlying mechanisms and constructed multiple comprehensive original mechanism summaries to establish a benchmark. Additionally, we have explored the cross-linking interactions between Pdots and nanomedicine, potential yet complete biological metabolic pathways, future research directions, and innovative solutions for integrating diagnosis and treatment strategies. This review presents the possible expectations and valuable insights for advancing Pdots, specifically from chemical, medical, and photophysical practitioners' standpoints.

Polymer-tethered quenched fluorescent probes for enhanced imaging of tumor associated proteases

Fluorescence-based contrast agents enable real-time detection of solid tumors and their neovasculature, making them ideal for use in image-guided surgery. Several agents have entered late-stage clinical trials or secured FDA approval, suggesting they are likely to become standard of care in cancer surgeries. One of the key parameters to optimize in contrast agent is molecular size, which dictates much of the pharmacokinetic and pharmacodynamic properties of the agent. Here, we describe the development of a class of protease-activated quenched fluorescent probes in which a N-(2-hydroxypropyl)methacrylamide copolymer is used as the primary scaffold. This copolymer core provides a high degree of probe modularity to generate structures that cannot be achieved with small molecules and peptide probes. We used a previously validated cathepsin substrate and evaluated the effects of length and type of linker as well as positioning of the fluorophore/quencher pair on the polymer core. We found that the polymeric probes could be optimized to achieve increased over-all signal and tumor-to-background ratios compared to the reference small molecule probe. Our results also revealed multiple structure-activity relationship trends that can be used to design and optimize future optical imaging probes. Furthermore, they confirm that a hydrophilic polymer is an ideal scaffold for use in optical imaging contrast probes, allowing a highly modular design that enables efficient optimization to maximize probe accumulation and overall biodistribution properties.

Photonics-powered augmented reality skin electronics for proactive healthcare: multifaceted opportunities

Rapid technological advancements have created opportunities for new solutions in various industries, including healthcare. One exciting new direction in this field of innovation is the combination of skin-based technologies and augmented reality (AR). These dermatological devices allow for the continuous and non-invasive measurement of vital signs and biomarkers, enabling the real-time diagnosis of anomalies, which have applications in telemedicine, oncology, dermatology, and early diagnostics. Despite its many potential benefits, there is a substantial information vacuum regarding using flexible photonics in conjunction with augmented reality for medical purposes. This review explores the current state of dermal augmented reality and flexible optics in skin-conforming sensing platforms by examining the obstacles faced thus far, including technical hurdles, demanding clinical validation standards, and problems with user acceptance. Our main areas of interest are skills, chiroptical properties, and health platform applications, such as optogenetic pixels, spectroscopic imagers, and optical biosensors. My skin-enhanced spherical dichroism and powerful spherically polarized light enable thorough physical inspection with these augmented reality devices: diabetic tracking, skin cancer diagnosis, and cardiovascular illness: preventative medicine, namely blood pressure screening. We demonstrate how to accomplish early prevention using case studies and emergency detection. Finally, it addresses real-world obstacles that hinder fully realizing these materials' extraordinary potential in advancing proactive and preventative personalized medicine, including technical constraints, clinical validation gaps, and barriers to widespread adoption.

Exploring the fluorescence properties of tellurium-containing molecules and their advanced applications

This review article explores the fascinating realm of fluorescence using organochalcogen molecules, with a particular emphasis on tellurium (Te). The discussion encompasses the underlying mechanisms, structural motifs influencing fluorescence, and the applications of these intriguing phenomena. This review not only elucidates the current state of knowledge but also identifies avenues for future research, thereby serving as a valuable resource for researchers and enthusiasts in the field of fluorescence chemistry with a focus on Te-based molecules. By highlighting challenges and prospects, this review sparks a conversation on the transformative potential of Te-containing compounds across different fields, ranging from environmental solutions to healthcare and materials science applications. This review aims to provide a comprehensive understanding of the distinct fluorescence behaviors exhibited by Te-containing compounds, contributing valuable insights to the evolving landscape of chalcogen-based fluorescence research.

Chemiluminescent Conjugated Polymer Nanoparticles for Deep-Tissue Inflammation Imaging and Photodynamic Therapy of Cancer

Deep-tissue optical imaging and photodynamic therapy (PDT) remain a big challenge for the diagnosis and treatment of cancer. Chemiluminescence (CL) has emerged as a promising tool for biological imaging and in vivo therapy. The development of covalent-binding chemiluminescence agents with high stability and high chemiluminescence resonance energy transfer (CRET) efficiency is urgent. Herein, we design and synthesize an unprecedented chemiluminescent conjugated polymer PFV-Luminol, which consists of conjugated polyfluorene vinylene (PFV) main chains and isoluminol-modified side chains. Notably, isoluminol groups with chemiluminescent ability are covalently linked to main chains by amide bonds, which dramatically narrow their distance, greatly improving the CRET efficiency. In the presence of pathologically high levels of various reactive oxygen species (ROS), especially singlet oxygen (1O2), PFV-Luminol emits strong fluorescence and produces more ROS. Furthermore, we construct the PFV-L@PEG-NPs and PFV-L@PEG-FA-NPs nanoparticles by self-assembly of PFV-Luminol and amphiphilic copolymer DSPE-PEG/DSPE-PEG-FA. The chemiluminescent PFV-L@PEG-NPs nanoparticles exhibit excellent capabilities for in vivo imaging in different inflammatory animal models with great tissue penetration and resolution. In addition, PFV-L@PEG-FA-NPs nanoparticles show both sensitive in vivo chemiluminescence imaging and efficient chemiluminescence-mediated PDT for antitumors. This study paves the way for the design of chemiluminescent probes and their applications in the diagnosis and therapy of diseases.

Unfolded Protein-Based Sandwich AIE Probe Imparts High Fluorescent Contrast for Pan-Cancer Surgical Navigation

Fluorescence imaging-guided navigation for cancer surgery has a promising clinical application. However, pan-cancer encompasses a wide variety of cancer types with significant heterogeneity, resulting in the lack of universal and highly contrasted fluorescent probes for surgical navigation. Here, we developed an aggregation-induced emission (AIE) probe (MI-AIE-TsG, MAT) with dual activation for pan-cancer surgical navigation. MAT weakly activates fluorescence by targeting the SUR1 protein on the endoplasmic reticulum (ER) through the TsG group. Subsequently, the sulfhydryl groups on the unfolded proteins, which are highly enriched in cancer ER, react with the maleimide (MI) of MAT through the thiol-ene click reaction, further enhancing the fluorescence. The formation of a SUR1-MAT-unfolded protein sandwich complex reinforces the restriction of intramolecular motion and eliminates photoinduced electron transfer of MAT, leading to high signal-to-noise (9.2) fluorescence imaging and use for surgical navigation of pan-cancer. The generally high content of unfolded proteins in cancer cells makes MAT imaging generalizable, and it currently has proven feasibility in ovarian, cervical, and breast cancers. Meanwhile, MAT promotes cellular autophagy by hindering protein folding, thereby inhibiting cancer cell proliferation. This generalizable, high-contrast AIE fluorescent probe spans the heterogeneity of pancreatic cancer, enabling precise pancreatic cancer surgery navigation and treatment.

Chemical Probes Review: Choosing the Right Path Towards Pharmacological Targets in Drug Discovery, Challenges and Future Perspectives

Chemical probes are essential for academic research and target validation for disease identification. They facilitate drug discovery, target function investigation, and translation studies. A chemical probe provides starting material that can accelerate therapeutic values and safety measures for identifying any biological target in drug discovery. Essential read outs depend on their versatility in biochemical testing, proving the hypothesis, selectivity, specificity, affinity towards the target site, and valuable in new therapeutic approaches. Disease management will depend upon chemical probes as a primitive tool to ascertain the physicochemical stability for in vivo and in vitro studies useful for clinical trials and industrial application in the future. For cancer research, bacterial infection, and neurodegenerative disorders, chemical probes are integrated circuits which are on pipeline for the drug discovery process Furthermore, pharmacological modulators incorporate activators, crosslinkers, degraders, and inhibitors. Reports accessed depend on their structural, mechanical, biochemical, and pharmacological characterization in drug discovery research. The perspective for designing any chemical probes concludes with the utilization of drug discovery and identification of the potential target. It focuses mainly on evidence-based studies and produces promising results in successfully delivering novel therapeutics to treat cancers and other disorders at the target site. Moreover, natural product pharmacophores like rapamycin, cephalosporin, and α-lactamase are utilized for drug discovery. Chemical probes revolutionize computational-based study design depending on identifying novel targets within the database framework. Chemical probes are the clinical answers for drug development and goforward tools in solving other riddles for scientists and researchers working in this industries.