Self‐Assembled Ag₂S‐QD Vesicles for In Situ Responsive NIR‐II Fluorescence Imaging‐Guided Photothermal Cancer Therapy

Abstract

Bioimaging guided photothermal therapy possesses great promise for lesion diagnosis and effective treatment. However, distinguishing lesion from normal tissues for precise cancer therapy remains a great challenge. Herein, a stimulation‐responsive assembled Ag2S vesicle (Ag2S Ve) is proposed by self‐assembly of Ag2S quantum dots (QDs) coated with pH‐sensitive copolymer thiolated polystyrene‐co‐poly(4‐vinylpyridine). The Ag2S Ve shows significant absorption enhancement in the near‐infrared (NIR) region and strong fluorescence inhibition in the second near infrared (NIR‐II) region. Triggered by the acidic environment, the release of Ag2S QDs promptly mediates the quenched NIR‐II fluorescence from “off” to “on.” In vivo studies reveal that the theranostic Ag2S Ve can be specifically activated in acidic tumor tissues, whereas it exhibits nonfunctional in normal tissues. Larger sizes endow vesicles a higher tumor accumulation efficiency and controllable disassembly shows illuminating characteristics toward lesion tissues, which provides an innovative therapeutic strategy for activated NIR‐II fluorescence imaging guided cancer therapy.

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

“…789 For example, quantum dots are ultrasmall nanoparticles with semiconducting properties whose fluorescence emission can be adjusted by changing their size, shape, and chemical composition; they are used for tumor imaging in vivo . 790–792 Mesoporous silica is widely studied as a carrier for chemotherapeutic drugs, and due to its passive targeting nature, the loaded drugs can achieve targeted sustained release in the tumor region, minimizing side effects. 793,794 Hafnium-based materials with strong X-ray absorption are used as radiosensitizers to enhance the radiotherapeutic efficacy of tumors.…”

Stimuli‐Responsive Hybrid Vesicle for Tumor Dual‐Model NIR‐II Photoacoustic and Fluorescence Imaging and Precise Radiotherapy

“…Analogously, the ≈8 nm Ag 2 S QDs were fabricated through the modified pyrolysis method (Figure S3, Supporting Information). [16] After anchoring the pH-responsive copolymer thiolated polystyrene-co-poly(4-vinylpyridine) (HS-PS-P4VP) and hydrophilic poly(ethylene glycol)-thiol (PEG-SH) polymerson to the surfaces of the as-prepared AuNNPs and Ag 2 S QDs via the covalent AuS or AgS bonds, the hybrid AuNNPs-Ag 2 S Ve was constructed successfully by the self-assembly of modified AuNNPs and Ag 2 S QDs through the oil-in-water emulsification method. Transmission electron microscopy (TEM) of AuNNPs-Ag 2 S Ve clearly showed spherical vesiclular nanostructure with good uniformity and monodispersity (Figure 1b).…”

Micro-/nano-fluidic devices and in vivo fluorescence imaging based on quantum dots for cytologic diagnosis

“…Ag 2 S QDs could be released from the Ag 2 S vesicle in the acidic tumor environment, which activated NIR-II fluorescence for imaging and NIR-II PTT of tumors. 89 Besides PTT, photodynamic therapy (PDT) that converts oxygen into reactive oxygen species (ROS) to kill tumors by oxidative damage to intracellular biomolecules is also noninvasive and highly selective. Zhang et al capped graphene QDs with silica nanospheres and decorated them with a carbon nitride (C 3 N 4 ) layer and RGD polymer, which achieved a triple-modal imaging-assisted cooperative PTT/PDT for monitoring tumor ablation.…”