Folded or nonfolded fluorophores incorporating naphthalene:Their fluorescent quenching driven by charge transfer or co-aggregation in the aqueous-organic binary solvent

Folded or nonfolded fluorophores incorporating naphthalene were synthesized and characterized by steady state fluorescence technique.Paraquat as an excellent quenching reagent quenched the fluorescence of Nel6 or nDs(n = 1-4) driven by charge transfer.Under aggregation of nDs,α-CD did not quench the fluorescence of 1D.At lower concentration,the quenching tendency ofα-CD against nDs is 2D>3D>4D,while at higher concentration,the tendency is 2D<3D<4D.α-CD showed the selective recognition on its flu...

Installing hydrogen bonds as a general strategy to control viscosity sensitivity of molecular rotor fluorophores Special Collection:Aggregation-Induced Processes and Functions

Molecular rotor-based fluorophores(RBFs)activate fluorescence upon increase of micro-viscosity,thus bearing a broad application promise in many fields.However,it remains a challenge to control how fluorescence of RBFs responds to viscosity changes.Herein,we demonstrate that the formation and regulation of intramolecular hydrogen bonds in the excited state of RBFs could modulate their rotational barrier,leading to a rational control of how their fluorescence can be activated by micro-viscosity.Based on this strategy,a series of RBFs were developed based on 4-hydroxybenzylidene-imidazolinone(HBI)that span a wide range of viscosity sensitivity.Combined with the AggTag method that we previously reported,the varying viscosity sensitivity and emission spectra of these probes enabled a dualcolor imaging strategy that detects both protein oligomers and aggregates during the multistep aggregation process of proteins in live cells.In summary,our work indicates that installing intracellular excited state hydrogen bonds to RBFs allows for a rational control of rotational barrier,thus allow for a fine tune of their viscosity sensitivity.Beyond RBFs,we envision similar strategies can be applied to control the fluorogenic behavior of a large group of fluorophores whose emission is dependent on excited state rotational motion,including aggregation-induced emission fluorophores.

Progress and Challenges of Water-soluble NIR-II Organic Fluorophores for Fluorescence Imaging In vivo

The small-molecule fluorophores for the second near-infrared(NIR-II,1000–1700 nm)window have attracted increasing attention in basic scientific research and preclinical practice owing to their deep-photo penetration,minimal physiological toxicity and simplicity of chemical modification.However,most of the reported small-molecule NIR-II fluorophores suffered from poor water solubility,which can easily cause organ toxicity.In addition,the aggregation caused by their poor water solubility in the aqueous solution would also result in weak fluorescence of these NIR-II fluorophores.Thus,it is highly desirable and valuable to develop water-soluble small-molecule NIR-II fluorophores with excellent photophysical properties for high-contrast in vivo imaging.In this review,we summarize the recent research advances in water-soluble small-molecule NIR-II fluorophores and highlight the representative bioimaging applications.Moreover,the potential challenges and perspectives of water-soluble small-molecule NIR-II fluorophores are discussed as well.We anticipate this review can help researchers to grab the latest information of water-soluble small-molecule fluorophores for NIR-II imaging,sequentially boosting their further development.

NIR-Ⅱ Fluorophores:From Synthesis to Biological Applications

Fluorescence imaging is a useful tool in the field of biomedical applications.However,its imaging capacity is limited by the depth of tissue that can be penetrated when using visible light(400-700 nm)or the first near-infrared window(NIR-Ⅰ,700-900 nm).To overcome the problem,fluorescence imaging in the second near-infrared window(NIR-Ⅱ,1000-1700 nm)has been developed to reduce photon scattering,auto-absorption and tissue autofluorescence to achieve high spatiotemporal resolution and deep imaging penetration.The key to NIR-Ⅱimaging is obtaining and analyzing highly selective information from functional fluorophores that emit in the 1000-1700 nm range.With the rapid development of multidisciplinary research,various types of NIR-Ⅱfluorophores have been produced and used in non-invasive,real-time NIR-Ⅱbiomedical applications.This review summarizes some of the most prevalent NIR-Ⅱfluorophores and their synthesis,such as organic fluorophores(OFs),single-walled carbon nanotubes(SWCNTs),quantum dots(QDs),and rare-earth nanoparticles(RENPs).On this basis,we describe the applications of these fluorophores in biomedical fields,including bioimaging,biosensing,phototherapy and surgical navigation.Additionally,major challenges and prospects of NIR-Ⅱbiomedical application will be further explored.

Recent advances on small-molecule fluorophores with emission beyond 1000 nm for better molecular imaging in vivo

In the second near-infrared channel(NIR-II, 1000–1700 nm), organic and inorganic fluorophores are designed with superior chemical/optical properties to provide real-time information with deeper penetration depth and higher resolution owing to the innate lower light scattering and absorption of the NIR-II imaging than conventional optical imaging. Among them, the small-molecule based fluorophores have been highlighted due to their desirable biocompatibility and favorable pharmacokinetics. In this review, we introduced the latest research progress of the rational design of small-molecule NIR-II fluorophores and their impressively biological applications including the NIR-II signal imaging,multimodal imaging and theranostic.

Small Molecular NIR-II Fluorophores for Cancer Phototheranostics

Phototheranostics integrates deep-tissue imaging with phototherapy(containing photothermal therapy and photodynamic therapy),holding great promise in early diagnosis and precision treatment of cancers.Recently,second near-infrared(NIR-II)fluorescence imaging exhibits the merits of high accuracy and specificity,as well as real-time detection.Among the NIR-II fluorophores,organic small molecular fluorophores have shown superior properties in the biocompatibility,variable structure,and tunable emission wavelength than the inorganic NIR-II materials.What’s more,some small molecular fluorophores also display excellent cytotoxicity when illuminated with the NIR laser.This review summarizes the progress of small molecular NIR-II fluorophores with different central cores for cancer phototheranostics in the past few years,focusing on the molecular structures and phototheranostic performances.Furthermore,challenges and prospects of future development toward clinical translation are discussed.

Laser Induced Fluorescence Studies of Blood Plasma and Tumor Tissue of Men with Prostate Tumors

Objectives: Fluorescence spectroscopy which can be used for optical tissue diagnosis of tumor pathology?deserves special interest. The purpose of the work was to study blood plasma and tumor tissue of men with different forms of prostate tumors by using laser induced fluorescence. Blood plasma and tumor tissue of the patients with benign hyperplasia of the prostate (BHP), BHP with inflammation, BHP with high grade PIN (BHP with HGPIN) and adenocarcinoma of prostate (CaP) have been studied. Results: In case of blood plasma fluorescence,?intensity of the plasma proteins corresponding peak (340 - 360 nm) was increasing in the following manner: control group → BHP → BHP with HGPIN → CaP. The intensity of the nicotinamide coenzymes correspond peak (440 - 460 nm) was increased in case of BHP with HGPIN and CaP patients, but decreased in case of BHP, compared to control. In case of tumor tissue, the changes of the collagen peak (390 - 400 nm) intensity have been revealed in all cases of prostate tumor tissues. These alterations point to altered collagen biosynthesis levels in different tumor tissues, that reflects the structural changes and characteristics of malignant transformation. Also the changes of the nicotinamide coenzymes peak (440 - 460 nm) intensity in all spectra of tumor tissues were observed. The highest intensity of the peak was observed in the spectra of BHP with HGPIN and in prostate cancer tissue. Conclusions: Alterations of the coenzymes peak intensities perfectly reflect and are in accordance with the specific energy metabolism of prostate epithelial cells. Normalization of fluorescent spectra from different forms of prostate tumor tissues has shown that, each form has typical spectral shape and ratio of fluorescence peaks intensities.

Fluorescent antibiotics for real-time tracking of pathogenic bacteria

The harm of pathogenic bacteria to humans has promoted extensive research on physiological processes of pathogens,such as the mechanism of bacterial infection,antibiotic mode of action,and bacterial antimicrobial resistance.Most of these processes can be better investigated by timely tracking of fluorophore-derived antibiotics in living cells.In this paper,we will review the recent development of fluorescent antibiotics featuring the conjugation with various fluorophores,and focus on their applications in fluorescent imaging and real-time detection for various physiological processes of bacteria in vivo.

STUDY ON ENHANCEMENT OF TUMOR-KILLING EFFECT AND FORMATION OF NEW FLUOROPHORE IN TUMOR CELLS

Hyperthermia (42-44℃) and photosensitizing therapy can destroy S180 tumor cells,reducemalignant ascites and prolong the survival times of mice with carcinomas.The highestcurative effect was observed when using a combination of the two treatments.Heating to44℃ has a greater destructive effect on tumor cells than has heating to 42℃.The resultsshow that this is due to a synergistic interaction between these two treatments.The fluores-cence spectrum of S180 cells was determined before and alter treatment,and the indicationwas that the synergistic effect is probably related to a new fluorescence product;the greaterthe intensity of the new fluorescence、the more marked the synergy of hyperthermia andphotosensitizing therapy.The maximum emission wavelength was 460nm (excitation wave-length 370nm).

Influence of sulfur doping on the molecular fluorophore and synergistic effect for citric acid carbon dots

In citric acid-based carbon dots,molecular fluorophore contributes greatly to the fluorescence emission.In this paper,the nitrogen and sulfur co-doped carbon dots(N,S-CDs)were prepared,and an independent sulfur source is selected to achieve the doping controllability.The influence of sulfur doping on the molecular fluorophore was systematically studied.The introduction of sulfur atoms may promote the formation of molecular fluorophore due to the increased nitrogen content in CDs.The addition surface states containing sulfur were produced,and S element exists as-SO_(3),and-SO_(4)groups.Appreciate ratio of nitrogen and sulfur sources can improve the fluorescence emission.The photoluminescence quantum yields(PLQY)is increased from 56.4%of the single N-doping CDs to 63.4%of double-doping CDs,which ascribes to the synergistic effect of molecular fluorophores and surface states.The sensitivity of fluorescence to pH response and various metal ions was also explored.

Spectroscopic Study of the Interactionbetween New Fluorescent Dyes with Nucleic Acids

A series of new dansylamide derivatives have been synthesized and the specific bindingaffinity of such fluorophores to nucleic acids has been investigated by using absorption, circulardichroism (CD), fluorescence and atomic force microscopy (AFM). The results indicate that thepositive charge of the ligand and the stacking between the dansy1 part of the ligand and theDNA base pair may play an important role when binding to polynucleotides.

Fluorescence guided intraluminal endoscopy in the gastrointestinal tract: A systematic review

BACKGROUND Conventional endoscopy is based on full spectrum white light.However,different studies have investigated the use of fluorescence based endoscopy systems where the white light has been supplemented by infrared light and the use of relevant fluorophores.Fluorescence endoscopy utilizes the fluorescence emitted from a fluorophore,visualizing what is not visible to the naked eye.AIM To explore the feasibility of fluorescence endoscopy and evaluate its use in diagnosing and evaluating gastrointestinal disease.METHODS We followed the PRISMA guidelines for this systematic review.The research covered five databases;PubMed,Scopus,Web of Science,Embase,and the Cochrane Collection,including only studies in English and Scandinavian languages.Authors screened title and abstract for inclusion,subsequently full-text for inclusion according to eligibility criteria listed in the protocol.The risk of bias was assessed for all studies according to the Newcastle-Ottawa Scale.The authors extracted the data and reported the results in both text and tables.RESULTS We included seven studies in the systematic review after screening a total of 2769 papers.The most prominent fluorophore was indocyanine green(n=6),and whereas one study(n=1)used Bevacizumab 800-CW.Three studies investigated fluorescence endoscopy in detecting varices,adenomas in patients with familial adenomatous polyposis and neoplasms in the gastrointestinal tract.Four studies evaluated the usefulness of fluorescence endoscopy in assessing tumor invasion.Three of the four studies reported an exceptional diagnostic accuracy(93%,89%and 88%)in assessing tumor invasion,thus representing better visualization and more correct diagnosis by fluorescence endoscopy compared with the conventional endoscopy.The relationship between the endoscopic findings,tumor invasion,and tumor vascularity was evaluated in two studies showing a significant correlation(dP<0.05 and bP<0.01).CONCLUSION The use of fluorescence endoscopy is a promising method adding diagnostic value in the detection of neoplasia,adenomas,and assessment of tumor invasion within the gastrointestinal tract.More studies are needed to utilize the feasibility of fluorescence endoscopy compared with other endoscopic methods.

Synthesis of a Fluorophore with Improved Optical Brightness

The synthesis and characterization of a novel fluorophore(1), with potential application as an optical brightener are reported. This compound was prepared by reacting 4,4-diaminostilbene-2,2-disulfonic acid with cyanuric chloride in the presence of Na2CO3 followed by the addition of trityl aniline. Solution and solid state fluorescence demonstrated a strong blue/purple emission centered at 450 nm. 1H-NMR spectroscopy, mass spectrometry analysis, elemental analysis, and DOSY-NMR were used for the characterization of the fluorophore.

Thiomethyl Derivatives of Two Oligo(p-phenylene vinylenes) as New Aggregation-Induced Piezofluorochromic Emitters

Two piezochromic fluorescent compounds are prepared by introducing thiomethyl substituents to the peripheralpositions of two related cyano oligo(p-phenylene vinylenes) (CN-OPV). The new derivatives, namely, 1,4-bis[2-cyano-2(4-thiomethylphenyl)ethenyl]benzene (TOPV1) and 1,4-bis(1-cyano-2-(4-thiomethylphenyl)ethenyl) benzene (TOPV2), are characterized by NMR, powder X-ray diffraction data (XRD) and differential scanning calorimetric (DSC) data. UV-Vis and fluorescence spectra are also measured. TOPV1 with the cyano groups farther away from the central aromatic ring is photoluminescent, and on application of pressure exhibits a more obvious color change and higher Stokes shift than those measured for TOPV2. We also observe piezochromic aggregation-induced emission (PAIE) for TOPV2, but TOPV1 does not exhibit any PAIE.

Enhanced optical imaging and fluorescent labeling for visualizing drug molecules within living organisms

The visualization of drugs in living systems has become key techniques in modern therapeutics.Recent advancements in optical imaging technologies and molecular design strategies have revolutionized drug visualization.At the subcellular level,super-resolution microscopy has allowed exploration of the molecular landscape within individual cells and the cellular response to drugs.Moving beyond subcellular imaging,researchers have integrated multiple modes,like optical near-infrared II imaging,to study the complex spatiotemporal interactions between drugs and their surroundings.By combining these visualization approaches,researchers gain supplementary information on physiological parameters,metabolic activity,and tissue composition,leading to a comprehensive understanding of drug behavior.This review focuses on cutting-edge technologies in drug visualization,particularly fluorescence imaging,and the main types of fluorescent molecules used.Additionally,we discuss current challenges and prospects in targeted drug research,emphasizing the importance of multidisciplinary cooperation in advancing drug visualization.With the integration of advanced imaging technology and molecular design,drug visualization has the potential to redefine our understanding of pharmacology,enabling the analysis of drug micro-dynamics in subcellular environments from new perspectives and deepening pharmacological research to the levels of the cell and organelles.

Dynamically Securing the Data by^(1)O_(2)Sensitization of Fluorescent Composites with a High Latency and Uncrackable Features

Dynamic fluorescent materials play a crucial role in secure inks for data encryption;however,they are still plagued by issues such as photodegradation,poor latency,and susceptibility to unauthorized access.Herein,we propose a photochemically modulated dynamic fluorescent encryption system based on^(1)O_(2)sensitization of fluorescent composites,comprising a^(1)O_(2)-sensitive fluorophore(F2)and non-emissive polymers.After UV irradiation,in-situ generated^(1)O_(2)from the polymer effectively binds with F2 to form endoperoxides(F2EPO),resulting in a significant redshift in emission,up to 150 nm.The^(1)O_(2)concentration is closely related to the irradiation time,rendering different fluorescent colors in a time-gated fashion.Moreover,the emission of F2EPO can be regulated by polymer chemical structure,molecular weight,and crosslinking density.Relying on these merits,we develop a dynamic data encryption method with various non-emissive polymers as the data storage media,UV light irradiation as the data encoder,and F2 as the data decoder.UV light irradiation of diverse polymer solutions generates^(1)O_(2)at different concentrations,effectively encoding the data,which remains invisible under both UV and natural lights.The addition of F2 to these irradiated polymer solutions produces different redshifted fluorescence,enabling secure data decryption.Attributing to the non-emissive nature of the polymers,time-gated readout fashion,excellent latency of^(1)O_(2),and subtle interactions between^(1)O_(2)and F2,this data encryption is nearly undecipherable.This work offers an advantage data encryption approach beyond the reach of conventional fluorophores.

Ultralong Organic Phosphorescence of Triazatruxene Derivatives for Dynamic Data Encryption and Anti-counterfeiting

Comprehensive Summary,Organic luminogens with persistent room temperature phosphorescence(RTP)have drawn tremendous attentions due to their promising potentials in optoelectronic devices,information storage,biological imaging,and anti-counterfeiting.In this work,six triazatruxene-based lumiogens with different peripheral substituents and configurations are synthesized and systematically studied.The results show that their fluorescence quantum yields in solid states range from 15.73%to 37.58%.Dispersing the luminogens as guest into the host(PPh_(3))could turn on the persistent RTP,where PPh_(3)acts as not only a rigid matrix to suppress the non-radiative transitions of the guest,but also provides energy transfer channels to the guest.The maximum phosphorescence efficiency and the longest lifetime could reach 29.35%and 0.99 s in co-crystal films of 6-TAT-CN/PPh_(3)and 5-TAT-H/PPh_(3),respectively.Moreover,these host-guest co-crystalline films exhibit great potentials in advanced dynamic data encryption and anti-counterfeiting.This work deepens the insight for low cost,halogen-free,and facile fabrication of all-organic persistent RTP materials.

3D cell-printing of gradient multi-tissue interfaces for rotator cuff regeneration

Owing to the prevalence of rotator cuff(RC)injuries and suboptimal healing outcome,rapid and functional regeneration of the tendon-bone interface(TBI)after RC repair continues to be a major clinical challenge.Given the essential role of the RC in shoulder movement,the engineering of biomimetic multi-tissue constructs presents an opportunity for complex TBI reconstruction after RC repair.Here,we propose a gradient cell-laden multi-tissue construct combined with compositional gradient TBI-specific bioinks via 3D cell-printing technology.In vitro studies demonstrated the capability of a gradient scaffold system in zone-specific inducibility and multi-tissue formation mimicking TBI.The regenerative performance of the gradient scaffold on RC regeneration was determined using a rat RC repair model.In particular,we adopted nondestructive,consecutive,and tissue-targeted near-infrared fluorescence imaging to visualize the direct anatomical change and the intricate RC regeneration progression in real time in vivo.Furthermore,the 3D cell-printed implant promotes effective restoration of shoulder locomotion function and accelerates TBI healing in vivo.In summary,this study identifies the therapeutic contribution of cell-printed constructs towards functional RC regeneration,demonstrating the translational potential of biomimetic gradient constructs for the clinical repair of multi-tissue interfaces.

Evolving a novel red-emitting two-photon dye with optically tunable amino group for monitoring the degree of hypoxia during liver fibrosis

Two-photon imaging has attracted increasing attention owing to its deep tissue imaging capabilities.Therefore,many fluorophores have been developed to satisfy its requirements.However,long-wavelength emission fluorophores with an optically tunable group are rarely developed.In this study,two longwavelength emission fluorophores with an optically tunable amino group were successfully developed by introducing strong electron acceptor and large conjugated group to the TPQL dye.TPCO_(2)displayed a bright red emission(λem=638 nm,Φ=0.15)together with high two-photon action cross section and good water solubility,which enabled higher signal-to-background ratios and deep tissue imaging.The proof-of-concept probe(TPCO-NO_(2))was successfully applied to the high signal-to-background ratio imaging of nitroreductase in liver fibrosis,further realizing diagnosis of the degree of hypoxia during liver fibrosis.

The function-oriented precursor selection for the preparation of carbon dots

As a new type of fluorescent nanomaterials,carbon dots(CDs)have exhibited excellent photoluminescence properties with tunable emission and high quantum yields,hence they have attracted an increasing interest in diverse research areas.The photoluminescence performance of CDs is primarily influenced by their precursors,which directly or indirectly determine the structures and specific functions of the resultant CDs.In this review,we aim to summarize the recent progress on synthesis of CDs using small aliphatic molecules,anilines,polyphenol,polycyclic aromatic hydrocarbons,organic dyes,or biomass as precursors.The associations of the physical and chemical properties of the CDs with their respective precursors are comprehensively investigated,and the potential applications and future development of CDs are discussed in detail.It is hoped that this review will open new horizons for CDs preparation by rational selection of the precursors from the vastly available carbon sources and the critical comments presented,here could inspire and guide future research in the design of multifunctional CDs.