Development of a reactive oxygen species (ROS)-responsive nanoplatform for targeted oral cancer therapy

Personalized Targeted Therapeutic Strategies against Oral Squamous Cell Carcinoma. An Evidence-Based Review of Literature

Oral squamous cell carcinoma (OSCC) is the most common type of malignant tumor in the head and neck, with a poor prognosis mainly due to recurrence and metastasis. Classical treatment modalities for OSCC like surgery and radiotherapy have difficulties in dealing with metastatic tumors, and together with chemotherapy, they have major problems related to non-specific cell death. Molecular targeted therapies offer solutions to these problems through not only potentially maximizing the anticancer efficacy but also minimizing the treatment-related toxicity. Among them, the receptor-mediated targeted delivery of anticancer therapeutics remains the most promising one. As OSCC exhibits a heterogeneous nature, selecting the appropriate receptors for targeting is the prerequisite. Hence, we reviewed the OSCC-associated receptors previously used in targeted therapy, focused on their biochemical characteristics and expression patterns, and discussed the application potential in personalized targeted therapy of OSCC. We hope that a better comprehension of this subject will help to provide the fundamental information for OSCC personalized therapeutic planning.

Low-Power Magnetic Resonance-Guided Focused Ultrasound Tumor Ablation upon Controlled Accumulation of Magnetic Nanoparticles by Cascade-Activated DNA Cross-Linkers

Magnetic resonance-guided focused ultrasound (MRgFUS) is a promising non-invasive surgical technique with spatial specificity and minimal off-target effects. Despite the expanding clinical applications, the major obstacles associated with MRgFUS still lie in low magnetic resonance imaging (MRI) sensitivity and safety issues. High ultrasound power is required to resist the energy attenuation during the delivery to the tumor site and may cause damage to the surrounding healthy tissues. Herein, a surface modification strategy is developed to simultaneously strengthen MRI and ultrasound ablation of MRgFUS by prolonging Fe₃O₄ nanoparticles' blood circulation and tumor-environment-triggered accumulation and retention at the tumor site. Specifically, reactive oxygen species-labile methoxy polyethylene glycol and pH-responsive DNA cross-linkers are modified on the surface of Fe₃O₄ nanoparticles, which can transform nanoparticles into aggregations through the cascade responsive reactions at the tumor site. Notably, DNA is selected as the pH-responsive cross-linker because of its superior biocompatibility as well as the fast and sensitive response to the weak acidity of 6.5-6.8, corresponding to the extracellular pH of tumor tissues. Due to the significantly enhanced delivery and retention amount of Fe₃O₄ nanoparticles at the tumor site, the MRI sensitivity was enhanced by 1.7-fold. In addition, the ultrasound power was lowered by 35% to reach a sufficient thermal ablation effect. Overall, this investigation demonstrates a feasible resolution to promote the MRgFUS treatment by enhancing the therapeutic efficacy and reducing the side effects, which will be helpful to guide the clinical practice in the future.

Current trends of targeted therapy for oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a malignant disease in the world which has a profound effect on human health and life quality. According to tumor stage and pathological diagnosis, OSCC is mainly treated by combinations of surgery, radiotherapy and chemotherapy. However, traditional treatment methods suffer from some limitations, such as systemic toxicity, limited therapeutic effect and drug resistance. With the rapid development of nanotechnology, nanodrug delivery systems (DDSs) and intelligent DDSs have been widely used in targeted therapy for OSCC. Meanwhile, the newly developed therapeutic techniques such as immunotherapy, gene therapy and bionic technology provide the possibility to realize the active targeted therapy. Here, the latest advances of target therapy for OSCC are reviewed, and their therapeutic remarks, current limits and future prospects are also systematically interpreted. It is believed that active and passive targeted therapies have great potentials for clinical transformation and application of OSCC, which will greatly improve human quality of life.

Applications of the ROS-Responsive Thioketal Linker for the Production of Smart Nanomedicines

Reactive oxygen species (ROS)-sensitive drug delivery systems (DDS) specifically responding to altered levels of ROS in the pathological microenvironment have emerged as an effective means to enhance the pharmaceutical efficacy of conventional nanomedicines, while simultaneously reducing side effects. In particular, the use of the biocompatible, biodegradable, and non-toxic ROS-responsive thioketal (TK) functional group in the design of smart DDS has grown exponentially in recent years. In the design of TK-based DDS, different technological uses of TK have been proposed to overcome the major limitations of conventional DDS counterparts including uncontrolled drug release and off-target effects. This review will focus on the different technological uses of TK-based biomaterials in smart nanomedicines by using it as a linker to connect a drug on the surface of nanoparticles, form prodrugs, as a core component of the DDS to directly control its structure, to control the opening of drug-releasing gates or to change the conformation of the nano-systems. A comprehensive view of the various uses of TK may allow researchers to exploit this reactive linker more consciously while designing nanomedicines to be more effective with improved disease-targeting ability, providing novel therapeutic opportunities in the treatment of many diseases.

Novel Prodrug Supramolecular Nanoparticles Capable of Rapid Mitochondrial-Targeted and ROS-Responsive for Pancreatic Cancer Therapy

Mitochondrial dysfunction is a feature of cancer cells and targeting cancer mitochondria has emerged as a promising anticancer therapy. In this study, a novel mitochondria-targeted and ROS-responsive drug delivery nanoplatform...

Stimuli-responsive drug delivery systems for head and neck cancer therapy

Head and neck cancer (HNC) is among the most common malignancy that has a profound impact on human health and life quality. The treatment for HNC, especially for the advanced cancer is stage-dependent and in need of combined therapies. Various forms of adjuvant treatments such as chemotherapy, phototherapy, hyperthermia, gene therapy have been included in the HNC therapy. However, there are still restrictions with traditional administration such as limited in situ therapeutic effect, systemic toxicity, drug resistance, etc. In recent years, stimuli-responsive drug delivery systems (DDSs) have attracted the great attention in HNC therapy. These intelligent DDSs could respond to unique tumor microenvironment, external triggers or dual/multi stimulus with more specific drug delivery and release, leading to enhanced treatment efficiency and less reduced side effects. In this article, recent studies on stimuli-responsive DDSs for HNC therapy were summarized, which could respond to endogenous and exogenous triggers including pH, matrix metalloproteinases (MMPs), reactive oxygen species (ROS), redox condition, light, magnetic field and multi stimuli. Their therapeutic remarks, current limits and future prospect for these intelligent DDSs were discussed. Furthermore, multifunctional stimuli-responsive DDSs have also been reviewed. With the modification of drug carriers or co-loading with therapeutic agents. Those intelligent DDSs showed more biofunctions such as combined therapeutic effects or integration of diagnosis and treatment for HNC. It is believed that stimuli-responsive drug delivery systems showed great potential for future clinic translation and application for the treatment of HNC.

Smart Design of Mitochondria-Targeted and ROS-Responsive CPI-613 Delivery Nanoplatform for Bioenergetic Pancreatic Cancer Therapy

Mitochondria, as the powerhouse of most cells, are not only responsible for the generation of adenosine triphosphate (ATP) but also play a decisive role in the regulation of apoptotic cell death, especially of cancer cells. Safe potential delivery systems which can achieve organelle-targeted therapy are urgently required. In this study, for effective pancreatic cancer therapy, a novel mitochondria-targeted and ROS-triggered drug delivery nanoplatform was developed from the TPP-TK-CPI-613 (TTCI) prodrug, in which the ROS-cleave thioketal functions as a linker connecting mitochondrial targeting ligand TPP and anti-mitochondrial metabolism agent CPI-613. DSPE-PEG2000 was added as an assistant component to increase accumulation in the tumor via the EPR effect. This new nanoplatform showed effective mitochondrial targeting, ROS-cleaving capability, and robust therapeutic performances. With active mitochondrial targeting, the formulated nanoparticles (TTCI NPs) demonstrate much higher accumulation in mitochondria, facilitating the targeted delivery of CPI-613 to its acting site. The results of in vitro antitumor activity and cell apoptosis revealed that the IC₅₀ values of TTCI NPs in three types of pancreatic cancer cells were around 20~30 µM, which was far lower than those of CPI-613 (200 µM); 50 µM TTCI NPs showed an increase in apoptosis of up to 97.3% in BxPC3 cells. Therefore, this mitochondria-targeted prodrug nanoparticle platform provides a potential strategy for developing safe, targeting and efficient drug delivery systems for pancreatic cancer therapy.

HOCl-Activated Aggregation of Gold Nanoparticles for Multimodality Therapy of Tumors

Tumor microenvironment-responsive nanodrugs offer promising opportunities for imaging-guided precision therapy with reduced side effects. Considering that the antitumor effect is closely related to the size of the nanodrugs, it is particularly important to develop a therapeutic system with size adjustability in the tumor microenvironment, which is still a great challenge in the field of nanotheranostics. Herein, a reactive oxygen species (ROS)-activated aggregation strategy is reported for imaging-guided precision therapy of tumors. The ROS-activated nanoplatform is constructed based on gold nanoparticles (AuNPs) coated with an HOCl probe on its surface (namely, Au-MB-PEG NPs). The Au-MB-PEG NPs show high sensitivity toward HOCl, resulting in the modulation of surface charge and rapid aggregation of AuNPs, and simultaneous release of methylene blue as a photosensitizer for photodynamic therapy (PDT). In the tumor environment, the aggregated AuNPs ensure higher tumor accumulation and retention. Furthermore, the redshift of the absorption of aggregated AuNPs leads to activated photoacoustic imaging signals and photothermal therapy (PTT) under near-infrared irradiation. Au-MB-PEG NPs thus efficiently inhibit the tumor growth through combined PTT-PDT therapy. This work contributes to the design of stimuli-induced size-aggregation nanodrugs, thereby attaining advanced performance in cancer diagnosis and treatment.

Nanoparticles in Dentistry: A Comprehensive Review

In recent years, nanoparticles (NPs) have been receiving more attention in dentistry. Their advantageous physicochemical and biological properties can improve the diagnosis, prevention, and treatment of numerous oral diseases, including dental caries, periodontal diseases, pulp and periapical lesions, oral candidiasis, denture stomatitis, hyposalivation, and head, neck, and oral cancer. NPs can also enhance the mechanical and microbiological properties of dental prostheses and implants and can be used to improve drug delivery through the oral mucosa. This paper reviewed studies from 2015 to 2020 and summarized the potential applications of different types of NPs in the many fields of dentistry.

[Reactive oxygen species stimuli-responsive nanocarriers]

纳米载体一般是由天然高分子或人工合成高分子组成的、纳米级范畴的运输系统,具有减少药物毒性、提高药物的靶向性、增加药物有效性等优点。随着生物医学技术的进步,有研究表明,作为氧化代谢产物的活性氧(ROS)在疾病部位常常伴随着过表达的异常现象。基于此,近年来ROS刺激响应纳米载体获得了关注和发展,以不同响应机制的ROS响应基团为基础,发展了一系列的ROS响应纳米载体,实现了疾病部位ROS刺激下的药物特异性可控释放。该文聚焦于近年来常用于纳米载体的ROS响应基团,依据元素划分为两大类:硫族元素类响应基团(硫醚、缩硫酮、硒化物、二硒化物、碲化物)和其他元素类响应基团(芳香硼酸酯、过氧草酸酯、二茂铁);通过不同的设计理念将其引入纳米载体,根据ROS响应纳米载体的不同响应机制(疏水-亲水相变、断裂),探讨了载体各自的ROS响应情况、体外药物释放情况,以及在活体中的应用情况。

Hypoxia-Mediated ROS Amplification Triggers Mitochondria-Mediated Apoptotic Cell Death via PD-L1/ROS-Responsive, Dual-Targeted, Drug-Laden Thioketal Nanoparticles

Amalgamation of the reactive oxygen species (ROS)-responsive stimulus with nanoparticles has gained considerable interest owing to their high tumor specificity. Hypoxia plays a pivotal role in the acceleration of intracellular ROS production. Herein, we report the construction of a cancer cell (PD-L1)- and ROS-responsive, dual-targeted, temozolomide (TMZ)-laden nanosystem which offers a better anticancer effect in a hypoxic tumor microenvironment. A dual-targeted system boosted permeation in the cancer cells. Hypoxic conditions elevating the high ROS level accelerated the in situ release of TMZ from anti-PD-L1-TKNPs. Hyperaccumulated ROS engendered from TMZ caused oxidative damage leading to mitochondria-mediated apoptosis. TMZ fabricated in the multifunctional nanosystem (anti-PD-L1-TMZ-TKNPs) provided excellent tumor accumulation and retarded tumor growth under in vivo conditions. The elevated apoptosis effect with the activation of an apoptotic marker, DNA double-strand breakage marker, and downregulation of the angiogenesis marker in the tumor tissue following treatment with anti-PD-L1-TMZ-TKNPs exerts robust anticancer effect. Collectively, the nanoconstruct offers deep tumor permeation and high drug release and broadens the application of the ROS-responsive nanosystem for a successful anticancer effect.

Nanoparticles for Oral Cancer Diagnosis and Therapy

Oral cancer is the sixth most common malignant cancer, affecting the health of people with an unacceptably high mortality rate. Despite numerous clinical methods in the diagnosis and therapy of oral cancer (e.g., magnetic resonance imaging, computed tomography, surgery, and chemoradiotherapy), they still remain far from optimal. Therefore, an urgent need exists for effective and practical techniques of early diagnosis and effective therapy of oral cancer. Currently, various types of nanoparticles have aroused wide public concern, representing a promising tool for diagnostic probes and therapeutic devices. Their inherent physicochemical features, including ultrasmall size, high reactivity, and tunable surface modification, enable them to overcome some of the limitations and achieve the expected diagnostic and therapeutic effect. In this review, we introduce different types of nanoparticles that emerged for the diagnosis and therapy of oral cancers. Then, the challenges and future perspectives for nanoparticles applied in oral cancer diagnosis and therapy are presented. The objective of this review is to help researchers better understand the effect of nanoparticles on oral cancer diagnosis and therapy and may accelerate breakthroughs in this field.

Engineering Polymeric Nanosystems against Oral Diseases

Nanotechnology and nanoparticles (NPs) are at the forefront of modern research, particularly in the case of healthcare therapeutic applications. Polymeric NPs, specifically, hold high promise for these purposes, including towards oral diseases. Careful optimisation of the production of polymeric NPs, however, is required to generate a product which can be easily translated from a laboratory environment to the actual clinical usage. Indeed, considerations such as biocompatibility, biodistribution, and biodegradability are paramount. Moreover, a pre-clinical assessment in adequate in vitro, ex vivo or in vivo model is also required. Last but not least, considerations for the scale-up are also important, together with an appropriate clinical testing pathway. This review aims to eviscerate the above topics, sourcing at examples from the recent literature to put in context the current most burdening oral diseases and the most promising polymeric NPs which would be suitable against them.

ROS-Responsive Polymeric Micelle for Improving Pesticides Efficiency and Intelligent Release

The low utilization rate of pesticides causes serious problems such as food safety and environmental pollution. Stimulus-responsive release can effectively improve the utilization rate of pesticides. Reactive oxygen species (ROS) burst, as an early event of plant-pathogen interaction, can stimulate the release of pesticides. In this work, a polymeric micelle with ROS-responsive was prepared and then Validamycin (Vail) was loaded into polymeric micelle to prepare Vail-loaded polymeric micelle. The Vail-loaded polymeric micelle displayed excellent ROS-dependent release kinetics. In vitro and in vivo antifungal experiments confirmed that the Vail-loaded polymeric micelle could improve antifungal efficacy against Rhizoctonia solani than with the Vail reagent. Therefore, as a biostimulation and controlled release system, ROS-responsive polymeric micelles can improve the utilization rate of pesticides and alleviate the problem of food safety and environmental pollution.

Synthesis, Characterization, and In Vitro Studies of an Reactive Oxygen Species (ROS)-Responsive Methoxy Polyethylene Glycol-Thioketal-Melphalan Prodrug for Glioblastoma Treatment

Glioblastoma (GBM) is the most frequent and aggressive primary tumor of the brain and averages a life expectancy in diagnosed patients of only 15 months. Hence, more effective therapies against this malignancy are urgently needed. Several diseases, including cancer, are featured by high levels of reactive oxygen species (ROS), which are possible GBM hallmarks to target or benefit from. Therefore, the covalent linkage of drugs to ROS-responsive molecules can be exploited aiming for a selective drug release within relevant pathological environments. In this work, we designed a new ROS-responsive prodrug by using Melphalan (MPH) covalently coupled with methoxy polyethylene glycol (mPEG) through a ROS-cleavable group thioketal (TK), demonstrating the capacity to self-assembly into nanosized micelles. Full chemical-physical characterization was conducted on the polymeric-prodrug and proper controls, along with in vitro cytotoxicity assayed on different GBM cell lines and “healthy” astrocyte cells confirming the absence of any cytotoxicity of the prodrug on healthy cells (i.e. astrocytes). These results were compared with the non-ROS responsive counterpart, underlining the anti-tumoral activity of ROS-responsive compared to the non-ROS-responsive prodrug on GBM cells expressing high levels of ROS. On the other hand, the combination treatment with this ROS-responsive prodrug and X-ray irradiation on human GBM cells resulted in an increase of the antitumoral effect, and this might be connected to radiotherapy. Hence, these results represent a starting point for a rationale design of innovative and tailored ROS-responsive prodrugs to be used in GBM therapy and in combination with radiotherapy.

Photosynthesis-inspired H2 generation using a chlorophyll-loaded liposomal nanoplatform to detect and scavenge excess ROS

A disturbance of reactive oxygen species (ROS) homeostasis may cause the pathogenesis of many diseases. Inspired by natural photosynthesis, this work proposes a photo-driven H2-evolving liposomal nanoplatform (Lip NP) that comprises an upconversion nanoparticle (UCNP) that is conjugated with gold nanoparticles (AuNPs) via a ROS-responsive linker, which is encapsulated inside the liposomal system in which the lipid bilayer embeds chlorophyll a (Chla). The UCNP functions as a transducer, converting NIR light into upconversion luminescence for simultaneous imaging and therapy in situ. Functioning as light-harvesting antennas, AuNPs are used to detect the local concentration of ROS for FRET biosensing, while the Chla activates the photosynthesis of H2 gas to scavenge local excess ROS. The results thus obtained indicate the potential of using the Lip NPs in the analysis of biological tissues, restoring their ROS homeostasis, possibly preventing the initiation and progression of diseases.

Development of upconversion nanoparticle-conjugated indium phosphide quantum dot for matrix metalloproteinase-2 cancer transformation sensing

Aim: Matrix metalloproteinase-2 (MMP2) plays an important role in extracellular matrix remodeling, that is, it increases significantly during cancer progression. In this regard, MMP2 monitoring is important. Experiment: A well-designed MMP2-sensitive polypeptide chain was used to link indium phosphide quantum dots (InP QDs) with upconversion nanoparticles (UCNPs) to form a nanocomposite that was utilized as biosensor. Results: We produced a biosensor that can be recognized by MMP2 and determined the presence or absence of MMP2 in cells by identifying difference in fluorescence wavelength. The InP QDs modified the arginylglycylaspartic acid molecules as targeting ligand based on chitosan. Conclusion: The MMP2-based biosensor, named UCNP-p@InP-cRGD, is sensitive and can be applied for biosensing probes.

In situ biosynthesized gold nanoclusters inhibiting cancer development via the PI3K–AKT signaling pathway

Nanomaterials have made great breakthroughs in drug delivery.

Enhanced combination cancer therapy using lipid-calcium carbonate/phosphate nanoparticles as a targeted delivery platform

Aim: Melanoma, the most life-threatening skin cancer, requires more effective therapies. Methodology: A new folic acid (FA) receptor-targeted lipid-coated calcium carbonate/phosphate (LCCP) nanoparticle was synthesized, incorporating two often-used therapeutics, cell death siRNA and α-tocopheryl succinate. Results: The nanoparticles were spherical, with an average size of 40 nm. The nanoparticles exhibited a high gene/drug loading efficiency (60%), with folic acid-enhanced cellular uptake. The nanoparticles with both therapeutics enhanced inhibition of B16F0 melanoma cell growth, showing a moderate synergistic effect. The mechanism of the inhibition is associated with induction of cell apoptosis and cell cycle arrest at G1 phase. Conclusion: Our data indicate that lipid-coated calcium carbonate/phosphate nanoparticles are a potential platform for targeted therapy for melanoma.

Enzymatic synthesis of selenium-containing amphiphilic aliphatic polycarbonate as an oxidation-responsive drug delivery vehicle

Although functional aliphatic polycarbonates (APCs) have attracted prominent research interest as stimuli-responsive biomaterials, the majority of functional APCs are fabricated by detrimental organometallic catalysts or organo-catalysts. Herein, a facile synthetic strategy based on enzymatic polymerization was developed to construct a selenium-containing amphiphilic aliphatic polycarbonate (mPEG-b-CMP₄₅). Specifically, the selenium in its backbone framework underwent a hydrophobic–hydrophilic transition upon exposure to the abnormal ROS level of the tumor, thus providing a promising platform for ROS-triggered drug release. This amphiphilic mPEG-b-CMP₄₅ efficiently encapsulated doxorubicin (DOX) via self-assembly in aqueous solution and showed an excellent ability to regulate the release of DOX in response to H₂O₂ at biologically relevant concentrations (100 μM). These DOX-loaded nanoparticles could easily be internalized into U87 cells and possess the inherent antitumor properties of DOX, while they exhibited much lower cytotoxicity in normal cells HL-7702. Moreover, in many cases, the introduction of selenium caused high cytotoxicity of the materials, but the cytotoxicity results in HL-7702 cells demonstrated the good biocompatibility of mPEG-b-CMP₄₅. These collective data suggested the potential use of mPEG-b-CMP₄₅ as a biocompatible and smart drug delivery vehicle.

A facile synthetic strategy based on enzymatic polymerization was developed to construct a ROS-responsive polycarbonate served as biocompatible drug vehicle.

RGD-modified polymer and liposome nanovehicles: Recent research progress for drug delivery in cancer therapeutics

Over the past few decades, as the demand for cancer treatment has increased, more rational treatment options (considering size, mode of administration, biocompatibility, efficacy, etc.) and plenty of specifically active targeted nanovehicles have been developed. Integrin receptors targeting are one of the most frequently used approaches because of its highly expressed in cancer cells. In particular, the arginine-glycine-aspartic acid (RGD) peptide and its derivatives have been widely used as ligands for integrin to increase direct targeting capabilies. Polymers as well as liposomes are commonly used as nanovehicles for drug delivery. A variety of work is focused on the RGD-modified polymer and liposome nanovehicles for cancer therapeutics. The goal of this article is to review the published literature in recent years concerning the RGD-modified liposome and polymer nanovehicles to highlight its successful designs for improving cancer therapy and discuss the current challenges as well as the possible development prospects.

Redox-responsive Drug Delivery Systems

Disbalanced reactive oxygen species (ROS) and glutathione (GSH) are characteristic features of tumor cells. High intracellular GSH concentration in tumor cells is a well-documented fact that leads to a very high reducing intracellular bio-milieu. High accumulation of ROS is known to occur in almost all cancers and can act as a two-edged sword during tumor development, by either promoting or inhibiting growth. These two features present unique opportunities to design drug delivery systems that are responsive to reduction or/and oxidation stimuli and has attracted accrued interest from researchers. These nanocarriers change their structural integrity, either through disassembly or degradation, to deliver their payload in the presence of the trigger. The aim of this chapter is to summarize the key developments in the design of materials with redox-responsive behaviour and their subsequent application in the field of nanomedicine targeting cancer. Strategies into exploiting both stimuli in a single nano drug delivery system to enhance therapeutic efficacy are also addressed.

Self-assembly of peptide amphiphiles for drug delivery: the role of peptide primary and secondary structures

Peptide amphiphiles (PAs), functionalized with alkyl chains, are capable of self-assembling into various nanostructures. Recently, PAs have been considered as ideal drug carriers due to their good biocompatibility, specific biological functions, and hypotoxicity to normal cells and tissues. Meanwhile, the nanocarriers formed by PAs are able to achieve controlled drug release and enhanced cell uptake in response to the stimulus of the physiological environment or specific biological factors in the location of the lesion. However, the underlying detailed drug delivery mechanism, especially from the aspect of primary and secondary structures of PAs, has not been systematically summarized or discussed. Focusing on the relationship between the primary and secondary structures of PAs and stimuli-responsive drug delivery applications, this review highlights the recent advances, challenges, and opportunities of PA-based functional drug nanocarriers, and their potential pharmaceutical applications are discussed.

Biodegradable, Hydrogen Peroxide, and Glutathione Dual Responsive Nanoparticles for Potential Programmable Paclitaxel Release

Reactive oxygen species (ROS) and glutathione (GSH) dual responsive nanoparticulate drug delivery systems (nano-DDSs) hold great promise to improve the therapeutic efficacy and alleviate the side effects of chemo drugs in cancer theranosis. Herein, hydrogen peroxide (H₂O₂) and GSH dual responsive thioketal nanoparticle (TKN) was rationally designed for paclitaxel (PTX) delivery. Compared to other stimuli-sensitive nano-DDSs, this dual responsive DDS is not only sensitive to biologically relevant H₂O₂ and GSH for on-demand drug release but also biodegradable into biocompatible byproducts after fulfilling its delivering task. Considering the heterogeneous redox potential gradient, the PTX loaded TKNs (PTX-TKNs) might first respond to the extracellular ROS and then to the intracellular GSH, achieving a programmable release of PTX at the tumor site. The selective toxicity of PTX-TKNs to tumor cells with high levels of ROS and GSH was verified both in vitro and in vivo.

ROS-responsive capsules engineered from green tea polyphenol–metal networks for anticancer drug delivery

Reactive oxygen species (ROS)-responsive nanocapsules for cancer drug delivery were engineered from green tea polyphenol–metal networks.

A sequential enzyme-activated and light-triggered pro-prodrug nanosystem for cancer detection and therapy

A sequential enzyme-activated and light-triggered pro-prodrug has been developed for cancer biomarker detection and on-demand therapy.

A reactive oxygen species–responsive prodrug micelle with efficient cellular uptake and excellent bioavailability

Stimuli-responsive polymeric drug delivery systems are of great interest in anticancer research. Here, a reactive oxygen species (ROS)–responsive prodrug was prepared by thioketal linkage of poly(ethylene glycol) (PEG) and the anticancer drug doxorubicin (DOX).

A self-immolative and DT-diaphorase-activatable prodrug for drug-release tracking and therapy

A DT-diaphorase-activatable theranostic prodrug has been developed for visualizing the release of active drug and enhancing the therapeutic effect.

A two-photon-activated prodrug for therapy and drug release monitoring

A two-photon-activated prodrug has been developed for drug release monitoring and photo-controllable therapy.

A ROS-responsive polymeric micelle with a π-conjugated thioketal moiety for enhanced drug loading and efficient drug delivery

As the implications of reactive oxygen species (ROS) are elucidated in many diseases, ROS-responsive nanoparticles are attracting great interest from researchers.