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Carrier‐free nanodrugs that integrate chemodrugs and other therapeutic agents demonstrate good efficacy and minimized side effects, showing promise for combined therapy. However, a key challenge lies in enhancing the bioavailability and therapeutic potential of the nanodrugs through a controllable assembly process. Herein, a carrier‐free photothermal nanodrug (ZPQ NPs) is constructed through flavonol‐driven assembly with amine‐substituted perylene diimide for enhanced chemo‐photothermal combined cancer therapy. The flavonol, particularly quercetin, facilitates J‐aggregation of perylene diimide derivatives within the nanodrug and contributes to multiple improvements, including red‐shifted absorption, enhanced fluorescence intensity, improved photothermal conversion efficiency as well as excellent photostability. Moreover, the nanodrug also demonstrates enhanced cellular uptake and intracellular reactive oxygen species scavenging capability. The combination of quercetin and photothermal effect effectively kills cancer cells, as well as alleviates inflammation following photothermal therapy. Guided by in vivo fluorescence imaging, the application of ZPQ NPs results in complete tumor elimination and effectively inhibits tumor recurrence through chemo‐photothermal combined therapy. This work presents a straightforward strategy for constructing carrier‐free nanodrugs that exhibit simultaneous enhancements in both photophysical properties and biological activity. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) have become an effective tool for tumor treatment. The combination of photodynamic therapy (PDT) and chemodynamic therapy (CDT) takes advantage of various ROS and enhances therapeutic effects. However, the activation of CDT usually occurs before PDT, which hinders the sustained maintenance of hydroxyl radicals (⋅OH) and reduces the treatment efficiency. Herein, we present a light‐triggered nano‐system based on molecular aggregation regulation for converting cancer therapy from PDT/photothermal therapy (PTT) to a long‐lasting CDT. The ordered J‐aggregation enhances the photodynamic properties of the cyanine moiety while simultaneously suppressing the chemodynamic capabilities of the copper‐porphyrin moiety. Upon light irradiation, Cu‐PCy JNPs demonstrate strong photodynamic and photothermal effects. Meanwhile, light triggers a rapid degradation of the cyanine backbone, leading to the destruction of the J‐aggregation. As a result, a long‐lasting CDT is sequentially activated, and the sustained generation of ⋅OH is observed for up to 48 hours, causing potent cellular oxidative stress and apoptosis. Due to their excellent tumor accumulation, Cu‐PCy JNPs exhibit effective in vivo tumor ablation through the converting therapy. This work provides a new approach for effectively prolonging the chemodynamic activity in ROS‐based cancer therapy. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) have become an effective tool for tumor treatment. The combination of photodynamic therapy (PDT) and chemodynamic therapy (CDT) takes advantage of various ROS and enhances therapeutic effects. However, the activation of CDT usually occurs before PDT, which hinders the sustained maintenance of hydroxyl radicals (⋅OH) and reduces the treatment efficiency. Herein, we present a light‐triggered nano‐system based on molecular aggregation regulation for converting cancer therapy from PDT/photothermal therapy (PTT) to a long‐lasting CDT. The ordered J‐aggregation enhances the photodynamic properties of the cyanine moiety while simultaneously suppressing the chemodynamic capabilities of the copper‐porphyrin moiety. Upon light irradiation, Cu‐PCy JNPs demonstrate strong photodynamic and photothermal effects. Meanwhile, light triggers a rapid degradation of the cyanine backbone, leading to the destruction of the J‐aggregation. As a result, a long‐lasting CDT is sequentially activated, and the sustained generation of ⋅OH is observed for up to 48 hours, causing potent cellular oxidative stress and apoptosis. Due to their excellent tumor accumulation, Cu‐PCy JNPs exhibit effective in vivo tumor ablation through the converting therapy. This work provides a new approach for effectively prolonging the chemodynamic activity in ROS‐based cancer therapy. [ABSTRACT FROM AUTHOR]

Photothermal therapy (PTT) represents a groundbreaking approach to targeted disease treatment by harnessing the conversion of light into heat. The efficacy of PTT heavily relies on the capabilities of photothermal agents (PTAs). Among PTAs, those based on organic dyes exhibit notable characteristics such as adjustable light absorption wavelengths, high extinction coefficients, and high compatibility in biological systems. However, a challenge associated with organic dye‐based PTAs lies in their efficiency in converting light into heat while maintaining stability. Manipulating dye aggregation is a key aspect in modulating non‐radiative decay pathways, aiming to augment heat generation. This review delves into various strategies aimed at improving photothermal performance through constructing aggregation. These strategies including protecting dyes from photodegradation, inhibiting non‐photothermal pathways, maintaining space within molecular aggregates, and introducing intermolecular photophysical processes. Overall, this review highlights the precision‐driven assembly of organic dyes as a promising frontier in enhancing PTT‐related applications. This article is categorized under:Therapeutic Approaches and Drug Discovery > Emerging TechnologiesTherapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic DiseaseDiagnostic Tools > In Vivo Nanodiagnostics and Imaging [ABSTRACT FROM AUTHOR]

Organic dyes hold great promise for application in photodynamic therapy (PDT). However, they currently face challenges such as inadequate photodynamic activity, limited tumor penetration, and constraints imposed by tumor hypoxia. Here, a facile and efficient strategy is presented for multi‐enhanced PDT through the fluorination of a squarylium indocyanine dye‐based photosensitizer (FCy). The amphiphilic FCy features perfluorooctane and PEG‐biotin moieties conjugated to a squarylium indocyanine core. In aqueous environments, FCy spontaneously self‐assembles into stable nano‐sized photosensitizers (FCy NPs), demonstrating a high oxygen loading ability attributable to the presence of perfluoroalkyl groups. Consequently, the aggregation of squarylium indocyanine dyes remarkably boosts the photodynamic effect, yielding a 15‐fold improvement in singlet oxygen quantum yield. Owing to the perfluoroalkyl group, FCy NPs exhibit increased endoplasmic reticulum (ER)‐ accumulating abilities, which further induce ER stress upon laser irradiation and enhance the PDT effect. Furthermore, the superior deep tumor penetration ability of FCy NPs is confirmed through both in vitro and in vivo studies. With efficient oxygen supply to the deep tumor regions, FCy NPs demonstrate potent imaging‐guided PDT against hypoxia tumors. The study substantiates the enhanced ER‐accumulating ability of the perfluoroalkyl group and presents a facile fluorination strategy for the multi‐enhancement of photosensitizers. [ABSTRACT FROM AUTHOR]

Self-assembly of dyes has become a flexible strategy to modulate their photophysical properties. H-aggregates show great potential to increase heat generation, while the precise designing of H-aggregates as efficient photothermal agents is still challenging. Herein, a quinoline cyanine (QCy) is developed for constructing stable H-aggregated nanoparticles (NPs) to significantly enhance photostability and photothermal conversion efficiency (PCE). With symmetrical rigid planar quinoline structures, QCy has a small and symmetrical dihedral angle (11.9°), which ensures excellent molecular planarity. In aqueous solution, the planar QCy can form close π−π molecular stacking, and fast self-assemble into stable H-aggregates even at low concentrations (1 × 10−7 M). QCy H-aggregates are sphere-like NPs (QCy NPs) with an average diameter of 120 nm and exhibit high stability. H-aggregation of QCy significantly enhances PCE from 20.1% (non-H-aggregated QCy) to 63.8% (QCy NPs). In addition, the positive charge of quaternarized quinoline provides mitochondrial anchoring ability, which further enhances the photothermal effect. With high PCE and tumor accumulation, QCy NPs in low-doses have been successfully used in photoacoustic imaging-guided tumor photothermal therapy. [ABSTRACT FROM AUTHOR]

Background: Nanomaterials are widely used as pesticide adjuvants to increase pesticide efficiency and minimize environmental pollution. But it is increasingly recognized that nanocarrier is a double-edged sword, as nanoparticles are emerging as new environmental pollutants. This study aimed to determine the biotoxicity of a widely applied star polycation (SPc) nanocarrier using Drosophila melanogaster, the fruit fly, as an in vivo model. Results: The lethal concentration 50 (LC50) value of SPc was identified as 2.14 g/L toward third-instar larvae and 26.33 g/L for adults. Chronic exposure to a sub lethal concentration of SPc (1 g/L) in the larval stage showed long-lasting adverse effects on key life history traits. Exposure to SPc at larval stage adversely impacted the lifespan, fertility, climbing ability as well as stresses resistance of emerged adults. RNA-sequencing analysis found that SPc resulted in aberrant expression of genes involved in metabolism, innate immunity, stress response and hormone production in the larvae. Orally administrated SPc nanoparticles were mainly accumulated in intestine cells, while systemic responses were observed. Conclusions: These findings indicate that SPc nanoparticles are hazardous to fruit flies at multiple levels, which could help us to develop guidelines for further large-scale application. [ABSTRACT FROM AUTHOR]

Stimuli-responsive fluorescent materials are ideal materials for paper anti-counterfeiting applications. However, the single responsiveness and the lacking of dynamics present the risk of being deciphered. Herein, we designed a series of cyanostilbene derivatives (ACNs) with fluorescence responses to acid or base. ACN1 with pyridine and hydroxyl groups exhibit dually responsive fluorescence "ON" in the solid state due to the ionization-enhanced intramolecular charge transfer (ICT) effect. Other ACNs with either pyridine or hydroxyl unit show only single responsiveness. Fluorescence papers (FPs) prepared by a simple dipping into the solutions of ACNs maintain the responsive fluorescence performance. FP1H with high ACN1 content exhibits time-dependent dynamic fluorescent colour changes by hydrogen chloride (HCl) vapour fumigation. The applications of paper anti-counterfeiting and information encryption are developed by combining ACN1 with other single-responsive ACNs. Moreover, a four-dimensional (4D) code with time-dependent information changes is designed. Our work provides new materials for the field of paper fluorescent anti-counterfeiting encryption. [ABSTRACT FROM AUTHOR]

A series of thionated perylenediimides with modulating phototheranostic modalities have been synthesized by a one-pot method for multiple anti-cancer applications. Compared to the initial and 4-tert-butyl phenol-substituted fluorescent perylenediimide, the obtained monothionated perylenediimide became photodynamic. With the increase of thionation degree, tetrathionated perylenediimide changed into an optimal photothermal agent. [ABSTRACT FROM AUTHOR]

Nowadays, photo‐based diagnosis and treatment techniques have been the focus in health‐related fields. Organic dyes with delicately designed structures and tunable optical properties were used for fluorescence and photoacoustic imaging as well as phototherapy including photodynamic and photothermal therapy. The theranostic agents exhibit better treatment efficacy with minimized invasiveness, which have shown great potential for disease treatment. To suit health‐related application, regulating the photophysical properties of functional organic dyes and improving their biocompatibility is the prerequisite for designing efficient optical diagnostic reagents. This review summarizes recent advances in the design, fabrication, and applications of functional organic dye‐based material in health‐related fields. The design and preparation strategies of these dyes mainly include tuning the absorption, emission, photodynamic and photothermal properties of dyes through chemical modification of chromophore scaffold, obtaining water‐soluble macromolecules through peripheral functional modification, constructing nanotheranostic reagents through self‐assembly process or preparing fluorescent detection devices. Based on these materials, functional organic dyes have been used in a variety of cancer treatment methods for bacterial detection and antibacterial fields, in vitro and in vivo disease detection, as well as fluorescence/photoacoustic imaging‐guided cancer therapy, which were summarized in this review. Finally, possible functionalization directions of organic dyes are also proposed to meet the needs of advanced health‐related applications. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) exhibits great potential for cancer therapy, but still suffers from nonspecific photosensitivity and poor penetration of photosensitizer. Herein, a smart perylene monoimide‐based nanocluster capable of enzyme‐triggered disassembly is reported as an activatable and deeply penetrable photosensitizer. A novel carboxylesterase (CE)‐responsive tetrachloroperylene monoimide (P1) was synthesized and assembled with folate‐decorated albumins into a nanocluster (FHP) with a diameter of circa 100 nm. Once P1 is hydrolyzed by the tumor‐specific CE, FHP disassembles into ultrasmall nanoparticles (ca. 10 nm), facilitating the deep tumor penetration of FHP. Furthermore, such enzyme‐triggered disassembly of FHP leads to enhanced fluorescence intensity (ca. 8‐fold) and elevated singlet oxygen generation ability (ca. 4‐fold), enabling in situ near‐infrared fluorescence imaging and promoted PDT. FHP permits remarkable tumor inhibition in vivo with minimal side effects through imaging‐guided, activatable, and deep PDT. This work confirms that this cascaded multifunctional control through enzyme‐triggered molecular disassembly is an effective strategy for precise cancer theranostics. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) exhibits great potential for cancer therapy, but still suffers from nonspecific photosensitivity and poor penetration of photosensitizer. Herein, a smart perylene monoimide‐based nanocluster capable of enzyme‐triggered disassembly is reported as an activatable and deeply penetrable photosensitizer. A novel carboxylesterase (CE)‐responsive tetrachloroperylene monoimide (P1) was synthesized and assembled with folate‐decorated albumins into a nanocluster (FHP) with a diameter of circa 100 nm. Once P1 is hydrolyzed by the tumor‐specific CE, FHP disassembles into ultrasmall nanoparticles (ca. 10 nm), facilitating the deep tumor penetration of FHP. Furthermore, such enzyme‐triggered disassembly of FHP leads to enhanced fluorescence intensity (ca. 8‐fold) and elevated singlet oxygen generation ability (ca. 4‐fold), enabling in situ near‐infrared fluorescence imaging and promoted PDT. FHP permits remarkable tumor inhibition in vivo with minimal side effects through imaging‐guided, activatable, and deep PDT. This work confirms that this cascaded multifunctional control through enzyme‐triggered molecular disassembly is an effective strategy for precise cancer theranostics. [ABSTRACT FROM AUTHOR]

Abstract: Fluorescent dyes with multi‐functionality are of great interest for photo‐based cancer theranostics. However, their low singlet oxygen quantum yield impedes their potential applications for photodynamic therapy (PDT). Now, a molecular self‐assembly strategy is presented for a nanodrug with a remarkably enhanced photodynamic effect based on a dye‐chemodrug conjugate. The self‐assembled nanodrug possesses an increased intersystem crossing rate owing to the aggregation of dye, leading to a distinct singlet oxygen quantum yield (Φ(1O2)). Subsequently, upon red light irradiation, the generated singlet oxygen reduces the size of the nanodrug from 90 to 10 nm, which facilitates deep tumor penetration of the nanodrug and release of chemodrug. The nanodrug achieved in situ tumor imaging and potent tumor inhibition by deep chemo‐PDT. Our work verifies a facile and effective self‐assembly strategy to construct nanodrugs with enhanced performance for cancer theranostics. [ABSTRACT FROM AUTHOR]

Abstract: Fluorescent dyes with multi‐functionality are of great interest for photo‐based cancer theranostics. However, their low singlet oxygen quantum yield impedes their potential applications for photodynamic therapy (PDT). Now, a molecular self‐assembly strategy is presented for a nanodrug with a remarkably enhanced photodynamic effect based on a dye‐chemodrug conjugate. The self‐assembled nanodrug possesses an increased intersystem crossing rate owing to the aggregation of dye, leading to a distinct singlet oxygen quantum yield (Φ(1O2)). Subsequently, upon red light irradiation, the generated singlet oxygen reduces the size of the nanodrug from 90 to 10 nm, which facilitates deep tumor penetration of the nanodrug and release of chemodrug. The nanodrug achieved in situ tumor imaging and potent tumor inhibition by deep chemo‐PDT. Our work verifies a facile and effective self‐assembly strategy to construct nanodrugs with enhanced performance for cancer theranostics. [ABSTRACT FROM AUTHOR]

Electrospun ultrathin fiber-based sensors are desirable because of their practicality and sensitivity. Ammonia-detection systems are in high demand in different areas, including the industrial and agricultural fields. However, current technologies rely on large and complex instruments that restrict their actual utilization. Herein, we report a flexible naked-eye ammonia sensor, the polylactic acid-cyanine (PLA-Cy) fibrous mat, which was fabricated by blending a carboxyl-functionalized cyanine dye ( D1) into electospun PLA porous fibers. The sensing mat was shown to undergo a naked-eye-detectable color change from white to blue upon exposure to ammonia vapor. The mat showed high selectivity to ammonia gas with a detection limit of 3.3 ppm. Aggregated D1 was first encapsulated by PLA and was then ionized by NH3. These mechanisms were examined by photophysical studies and scanning electron microscopy. The aggregation-deaggregation process of D1 in the PLA-Cy fibrous mat led to the color change. This work provides a facile method for the naked-eye detection of ammonia and a novel strategy for the use of organic dyes in ammonia sensing. [ABSTRACT FROM AUTHOR]

A novel amphiphilic squarylium indocyanine (LysoCy) is reported for remarkable lysosome tracking in live cells. LysoCy performs as a promising lysosome tracker with low cytotoxicity, a strong binding affinity and clear subcellular labelling. The long-term dynamics of lysosomes can be revealed by LysoCy for up to 2 days of culture, while the working duration of commercial dye is no longer than 1 hour. Our work provides a good alternative tool for long-term live cell imaging. [ABSTRACT FROM AUTHOR]

Systems that exhibit light-driven fluorescence change have received much attention due to their applications in luminescent switches or as sensors. However, such solid-state systems are still limited relative to those in solution form, and how to obtain photochromic fluorescent film materials for use in device fabrication is a long-standing problem. In this work, one-dimensional (1D) solid-state microcrystals combining a host molecule cyclodextrin (CD) and UV-responsive guest molecule spiropyran (SP) have been developed, which present a light-driven fluorescence change based on the isomerization of the SP molecule in the CD matrix. Firstly, the supramolecular forces including inherent hydrogen bonding and hydrophobic interactions in this self-assembled system were studied using electrospray ionization mass spectrometry (ESI-MS), isothermal titration calorimetry (ITC), and Fourier transform infrared spectra (FTIR). The scanning electron microscopy (SEM) comparison between the SP@CD system and the pristine CD or SP confirms that the SP guest plays a crucial role in the formation of 1D microcrystals. Then, through a spin-casting process, a thin film of SP@CD microcrystals was further fabricated, which shows a reversible photochromic fluorescence between fluorescence-free and high red-emission states. Moreover, the open-ring form of SP@CD microcrystals also presents two-photon emission and polarized fluorescence. Therefore, this work has offered a facile way to obtain a reversible photochromic fluorescent film, which may be applied in dynamic light-controlled fluorescent sensors and two-photon imaging. [ABSTRACT FROM AUTHOR]

pH indicators based on optical analysis play an important role in monitoring pH changes. Squarylium indocyanine (SICy) dyes have been developed to be used as extremely alkaline solution sensors. The absorbance and fluorescence intensities of the SICy dyes were quenched at a pH value of 13, and then recovered by adding acid to adjust the pH to 7. This reversible switching process could be repeated several times without significant loss of fluorescence. NMR and mass spectrometry analyses demonstrate nucleophilic addition of hydroxide ions to the N heterocycle. This study opens a new avenue to the design of fluorescent ratiometrics in extremely alkaline systems. [ABSTRACT FROM AUTHOR]

Dually cross‐linked supramolecular hydrogels (DCSH) are designed to show responsive properties while maintaining the gel structure by introducing two different kinds of cross‐links. This is realized by utilizing a photo‐cross‐linker for permanent cross‐linking and β‐cyclodextrin (β‐CD) and ferrocene (Fc) as host–guest recognition pair. The DCSH shows increased swelling in the presence of the small target molecule adamantane amine (Ada). Ada can break the non‐covalent bonding between β‐CD and Fc through competitive molecular guest interaction with β‐CD. By using a combination of surface plasmon resonance and optical waveguide spectroscopy, it is possible to use this behavior to construct a reversible sensor for specific small molecule detection. [ABSTRACT FROM AUTHOR]