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Metal ions are widely present in biological systems and participate in many critical biochemical processes such as material transportation, energy conversion, information transmission and metabolic regulation, making them indispensable substance in our body. They can cause health problems when deficiency or excess occurs. To understand various metabolic processes and facilitate diseases diagnosis, it is very important to measure the content and monitor the distribution of metal ions in individual cells, tissues and whole organisms. Among the various methods for metal ion detection, fluorescent sensors with organic dyes have attracted tremendous attention due to many advantages such as high fluorescence quantum yield, facile modification approaches and biocompatibility in addition to operation ease, high sensitivity, fast detection speed, and real-time detection. This review summarizes the recent progress on the detection and imaging of the metal ions in biological systems including Na+, K+, Ca2+, Mg2+, Fe2+/Fe3+, Zn2+, and Cu2+ provides an opinion on remaining challenges to be addressed in this field.

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]

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]