Photothermal-Controlled Generation of Alkyl Radical from Organic Nanoparticles for Tumor Treatment

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

Accurate Electronic and Optical Properties of Organic Doublet Radicals Using Machine Learned Range-Separated Functionals

Luminescent organic semiconducting doublet-spin radicals are unique and emergent optical materials because their fluorescent quantum yields (Φfl) are not compromised by the spin-flipping intersystem crossing (ISC) into a dark high-spin state. The multiconfigurational nature of these radicals challenges their electronic structure calculations in the framework of single-reference density functional theory (DFT) and introduces room for method improvement. In the present study, we extended our earlier development of ML-ωPBE [J. Phys. Chem. Lett., 2021, 12, 9516-9524], a range-separated hybrid (RSH) exchange-correlation (XC) functional constructed using the stacked ensemble machine learning (SEML) algorithm, from closed-shell organic semiconducting molecules to doublet-spin organic semiconducting radicals. We assessed its performance for a new test set of 64 doublet-spin radicals from five categories while placing all previously compiled 3926 closed-shell molecules in the new training set. Interestingly, ML-ωPBE agrees with the nonempirical OT-ωPBE functional regarding the prediction of the molecule-dependent range-separation parameter (ω), with a small mean absolute error (MAE) of 0.0197 a0-1, but saves the computational cost by 2.46 orders of magnitude. This result demonstrates an outstanding domain adaptation capacity of ML-ωPBE for diverse organic semiconducting species. To further assess the predictive power of ML-ωPBE in experimental observables, we also applied it to evaluate absorption and fluorescence energies (Eabs and Efl) using linear-response time-dependent DFT (TDDFT), and we compared its behavior with nine popular XC functionals. For most radicals, ML-ωPBE reproduces experimental measurements of Eabs and Efl with small MAEs of 0.299 and 0.254 eV, only marginally different from those of OT-ωPBE. Our work illustrates a successful extension of the SEML framework from closed-shell molecules to doublet-spin radicals and will open the venue for calculating optical properties for organic semiconductors using single-reference TDDFT.

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

Anatase TiO2-x and zwitterionic porphyrin polymer-based nanocomposite for enhanced cancer photodynamic therapy

Photodynamic therapy has been used as a treatment option for cancer; however, the existing TiO2 photosensitizer does not have the ability to specifically target cancer cells. This lack of selectivity reduces its effectiveness in overcoming cancer resistance. To improve photodynamic therapy outcomes, an innovative solution is proposed. In this study, we report on the compounding of a zwitterionic covalent organic polymer (COP) with a TiO2 photosensitizer for the first time. The aim is to overcome cancer cellular resistance. A one-pot synthetic strategy, which includes the construction of a porphyrin-based COP has been employed. This strategy has also been applied to the rapid preparation of anatase defective TiO2 (TiO2-x). To improve the hydrophilic and antifouling properties of the polymer, zwitterion L-cysteine has been conjugated with a porphyrin-based COP using a thiol-ene "click chemistry" reaction. The novel zwitterionic porphyrin-based COP has the ability to trigger biodegradation under the acid microenvironment due to the presence of acid-sensitive β-thioether esters. When combined with TiO2-x, the resultant nanocomposite produces an enhanced photodynamic therapy effect for drug-resistant cancer cells under NIR laser irradiation. This is due to the strong mutual sensitization of zwitterionic porphyrin-based COP and TiO2-x. Importantly, the nanocomposite delivery system exhibits excellent cytocompatibility in the dark and has the potential to improve the accuracy of cancer diagnosis through fluorescence imaging. The results of this study demonstrate the potential application of this alternative nanocomposite delivery system for remote-controllable photodynamic therapy of tumors.

Two-photon, red light uncaging of alkyl radicals from organorhodium(III) phthalocyanine complexes

A stepwise two-photon, red light excitation of organorhodium(III) phthalocyanine complexes was found to induce the activation of the axial metal-carbon bond to generate alkyl radicals/aldehydes. The cooperative action of the photouncaging reaction and the photochemical generation of reactive oxygen species were indicated to induce the cell deaths.

Nanozyme hydrogel for enhanced alkyl radical generation and potent antitumor therapy

Alkyl radicals (R˙), which do not rely on oxygen generation for causing cellular stress, have been applied in tumor treatment, but a large amount of glutathione (GSH) in the tumor cells reacts with alkyl radicals, thereby reducing their antitumor effect. In this study, an enhanced alkyl radical generation system responsive to near-infrared light was designed. The alkyl radical trigger 2,2'-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) and nanozyme pyrite (FeS₂) were encapsulated in agarose hydrogel to prepare the AIPH-FeS₂-hydrogel (AFH) system. FeS₂ can be used as a photothermal agent to convert near-infrared light energy into heat energy, leading to the dissolution of the hydrogel. AIPH is simultaneously induced to produce alkyl radicals. FeS₂ can also be used as an oxidative stress amplifier to reduce intracellular GSH content, thereby boosting the therapeutic effect of alkyl radicals. Eventually, the oxygen-independent free radicals generated by the AFH system under near-infrared laser irradiation and photothermal treatment can kill cancer cells through the synergistic oxidation/photothermal effect. The AFH system developed herein provides new insights into enhancing the therapeutic effect of alkyl radicals.

Research Progress of Conjugated Nanomedicine for Cancer Treatment

The conventional cancer therapeutic modalities include surgery, chemotherapy and radiotherapy. Although immunotherapy and targeted therapy are also widely used in cancer treatment, chemotherapy remains the cornerstone of tumor treatment. With the rapid development of nanotechnology, nanomedicine is believed to be an emerging field to further improve the efficacy of chemotherapy. Until now, there are more than 17 kinds of nanomedicine for cancer therapy approved globally. Thereinto, conjugated nanomedicine, as an important type of nanomedicine, can not only possess the targeted delivery of chemotherapeutics with great precision but also achieve controlled drug release to avoid adverse effects. Meanwhile, conjugated nanomedicine provides the platform for combining several different therapeutic approaches (chemotherapy, photothermal therapy, photodynamic therapy, thermodynamic therapy, immunotherapy, etc.) with the purpose of achieving synergistic effects during cancer treatment. Therefore, this review focuses on conjugated nanomedicine and its various applications in synergistic chemotherapy. Additionally, the further perspectives and challenges of the conjugated nanomedicine are also addressed, which clarifies the design direction of a new generation of conjugated nanomedicine and facilitates the translation of them from the bench to the bedside.

Recent Advances in Strategies for Addressing Hypoxia in Tumor Photodynamic Therapy

Photodynamic therapy (PDT) is a treatment modality that uses light to target tumors and minimize damage to normal tissues. It offers advantages including high spatiotemporal selectivity, low side effects, and maximal preservation of tissue functions. However, the PDT efficiency is severely impeded by the hypoxic feature of tumors. Moreover, hypoxia may promote tumor metastasis and tumor resistance to multiple therapies. Therefore, addressing tumor hypoxia to improve PDT efficacy has been the focus of antitumor treatment, and research on this theme is continuously emerging. In this review, we summarize state-of-the-art advances in strategies for overcoming hypoxia in tumor PDTs, categorizing them into oxygen-independent phototherapy, oxygen-economizing PDT, and oxygen-supplementing PDT. Moreover, we highlight strategies possessing intriguing advantages such as exceedingly high PDT efficiency and high novelty, analyze the strengths and shortcomings of different methods, and envision the opportunities and challenges for future research.

Alkylverdazyls as a Source of Alkyl Radicals for Light-Triggered Cancer Cell Death

Two alkylated verdazyl radicals (AlkVZs) were investigated as active compounds for photoinitiated controlled MCF-7 cell death. Observed results unambiguously showed that AlkVZ could be a potential structural moiety for the design of a novel family of photodynamic therapy agents. The main advantage of the proposed substances is an oxygen-independent generation of active radicals, which play a pivotal role in the treatment of oxygen-deficient tumors.

Monocomponent Nanodots with Dichromatic Output Regulated by Synergistic Dual-Stimuli for Cervical Cancer Tissue Imaging and Photodynamic Tumor Therapy

Inflammation exists in the microenvironment of most, if not virtually all, tumors, which greatly exacerbates the difficulty of cancer treatment. Considering the superiority of activatable photosensitizers (PSs), a novel strategy of 'making friends with the enemy' for tumor treatment was proposed. In this strategy, the "enemy" refers to inflammatory cytokines and the tumor site is targeted by detecting the enemy. Upon detection, a dichromatic fluorescence signal is released and the PS is activated specifically by the inflammatory cytokines. In this study, a multifunctional PS (TPE-PTZ-Py) was rationally designed, which can be activated specifically under the synergistic action of hypochlorous acid (HClO) (one kind of inflammatory cytokines) and acid (one typical marker of tumor), and output a ratiometric fluorescence signal simultaneously. The sulfoxide analogue (TPE-PTZO-PyH) as the response product effectively produced ¹O₂ (1.8-fold higher than that obtained with Rose Bengal) and showed high phototoxicity (IC₅₀ < 7.6 μM). More importantly, imaging analyses confirmed that TPE-PTZ-Py could be activated in human cervical cancer tissue. To date, several phenothiazine (PTZ)-based fluorescent probes have been developed for the selective sensing and imaging of HClO in subcellular organelles; however, this is the first phenothiazine-based nanodrug designed for the treatment of inflammation-associated tumors with a few side effects.

Photoactivatable nanogenerators of reactive species for cancer therapy

In recent years, reactive species-based cancer therapies have attracted tremendous attention due to their simplicity, controllability, and effectiveness. Herein, we overviewed the state-of-art advance for photo-controlled generation of highly reactive radical species with nanomaterials for cancer therapy. First, we summarized the most widely explored reactive species, such as singlet oxygen, superoxide radical anion (O2 ●-), nitric oxide (●NO), carbon monoxide, alkyl radicals, and their corresponding secondary reactive species generated by interaction with other biological molecules. Then, we discussed the generating mechanisms of these highly reactive species stimulated by light irradiation, followed by their anticancer effect, and the synergetic principles with other therapeutic modalities. This review might unveil the advantages of reactive species-based therapeutic methodology and encourage the pre-clinical exploration of reactive species-mediated cancer treatments.

Beyond DNA-targeting in Cancer Chemotherapy. Emerging Frontiers - A Review

Modern anti-cancer drugs target DNA specifically for rapid division of malignant cells. One downside of this approach is that they also target other rapidly dividing healthy cells, such as those involved in hair growth leading to serious toxic side effects and hair loss. Therefore, it would be better to develop novel agents that address cellular signaling mechanisms unique to cancerous cells, and new research is now focussing on such approaches. Although the classical chemotherapy area involving DNA as the set target continues to produce important findings, nevertheless, a distinctly discernible emerging trend is the divergence from the cisplatin operation model that uses the metal as the primary active center of the drug. Many successful anti-cancer drugs present are associated with elevated toxicity levels. Cancers also develop immunity against most therapies and the area of cancer research can, therefore, be seen as an area with a high unaddressed need. Hence, ongoing work into cancer pathogenesis is important to create accurate preclinical tests that can contribute to the development of innovative drugs to manage and treat cancer. Some of the emergent frontiers utilizing different approaches include nanoparticles delivery, use of quantum dots, metal complexes, tumor ablation, magnetic hypothermia and hyperthermia by use of Superparamagnetic Iron oxide Nanostructures, pathomics and radiomics, laser surgery and exosomes. This review summarizes these new approaches in good detail, giving critical views with necessary comparisons. It also delves into what they carry for the future, including their advantages and disadvantages.

Beyond Photo: Xdynamic Therapies in Fighting Cancer

Reactive oxygen species (ROS)-related therapeutic approaches are developed as a promising modality for cancer treatment because the aberrant increase of intracellular ROS level can cause cell death due to nonspecific oxidation damage to key cellular biomolecules. However, the most widely considered strategy, photodynamic therapy (PDT), suffers from critical limitations such as limited tissue-penetration depth, high oxygen dependence, and phototoxicity. Non-photo-induced ROS generation strategies, which are defined as Xdynamic therapies (X = sono, radio, microwave, chemo, thermo, and electro), show good potential to overcome the drawbacks of PDT. Herein, recent advances in the development of Xdynamic therapies, including the design of systems, the working mechanisms, and examples of cancer therapy application, are introduced. Furthermore, the approaches to enhance treatment efficiency of Xdynamic therapy are highlighted. Finally, the perspectives and challenges of these strategies are also discussed.

Recent Progress of Alkyl Radicals Generation-Based Agents for Biomedical Applications

Photodynamic therapy (PDT) is extensively explored for anticancer and antibacterial applications. It typically relies on oxygen-dependent generation of reactive oxygen species (ROS) to realize its killing effect. This type of therapy modality shows compromised therapeutic results for treating hypoxic tumors or bacteria-infected wounds. Recently, alkyl radicals attracted much attention as they can be generated from some azo-based initiators only under mild heat stimulus without oxygen participation. Many nanocarriers or hydrogel systems have been developed to load and deliver these radical initiators to lesion sites for theranostics. These systems show good anticancer or antimicrobial effect in hypoxic environment and some of them possess specific imaging abilities providing precise guidance for treatment. This review summarizes the developed materials that aim at treating hypoxic cancer and bacteria-infected wound by using this kind of oxygen-irrelevant alkyl radicals. Based on the carrier components, these agents are divided into three groups: inorganic, organic, as well as inorganic and organic hybrid carrier-based therapeutic systems. The construction of these agents and their specific advantages in biomedical field are highlighted. Finally, the existing problems and future promising development directions are discussed.

Nanoscale Covalent Organic Frameworks with Donor-Acceptor Structure for Enhanced Photothermal Ablation of Tumors

Covalent organic frameworks (COFs) have shown great potential in catalysis and the biomedical fields, but monodisperse COFs with tunable sizes are hard to obtain. Herein, we successfully developed a series of COFs based on electron donor-acceptor strategy in mild conditions. The synthetic COFs exhibit excellent colloidal stability with uniform spherical morphology. The sizes can be flexibly adjusted by the amount of catalyst, and the absorption spectra also vary with the sizes. By changing the electron-donating ability of the monomers, the corresponding COFs possess a wide range of absorption spectra, which can be even extended to the second near-infrared biowindow. The obtained COFs possess potent photothermal activity under laser irradiation, and could inhibit the growth of tumors effectively. This work provides a strategy for the synthesis of monodisperse COFs with variable absorption for their potential applications.

Engineering Oxygen-Irrelevant Radical Nanogenerator for Hypoxia-Independent Magnetothermodynamic Tumor Nanotherapy

Tumor hypoxia substantially lowers the treatment efficacy of oxygen-relevant therapeutic modalities because the production of reactive oxygen species in oxygen-relevant anticancer modalities is highly dependent on oxygen level in tumor tissues. Here a distinctive magnetothermodynamic anticancer strategy is developed that takes the advantage of oxygen-irrelevant free radicals produced from magnetothermal decomposable initiators for inducing cancer-cell apoptosis in vitro and tumor suppression in vivo. Free-radical nanogenerator is constructed through in situ engineering of a mesoporous silica coating on the surface of superparamagnetic Mn and Co-doped nanoparticles (MnFe₂ O₄ @CoFe₂ O₄ , denoted as Mag) toward multifunctionality, where mesoporous structure provides reservoirs for efficient loading of initiators and the Mag core serves as in situ heat source under alternating magnetic field (AMF) actuation. Upon exposure to an exogenous AMF, the magnetic hyperthermia effect of superparamagnetic core lead to the rapid decomposition of the loaded/delivered initiators (AIPH) to produce oxygen-irrelevant free radicals. Both the magnetothermal effect and generation of toxic free radicals under AMF actuation are synergistically effective in promoting cancer-cell death and tumor suppression in the hypoxic tumor microenvironment. The prominent therapeutic efficacy of this radical nanogenerator represents an intriguing paradigm of oxygen-irrelevant nanoplatform for AMF-initiated synergistic cancer treatment.

Cascade Drug-Release Strategy for Enhanced Anticancer Therapy

Chemotherapy serves as one of the most effective approaches in numerous tumor treatments but also suffers from the limitations of low bioavailability and adverse side effects due to premature drug leakage. Therefore, it is crucial to realize accurate on-demand drug release for promoting the application of chemotherapeutic agents. To achieve this, stimuli-responsive nanomedicines that can be activated by delicately designed cascade reactions have been developed in recent years. In general, the nanomedicines are triggered by an internal or external stimulus, generating an intermediate stimulus at tumor site, which can intensify the differences between tumor and normal tissues; the drug release process is then further activated by the intermediate stimulus. In this review, the latest progress made in cascade reactions-driven drug-release modes, based on the intermediate stimuli of heat, hypoxia, and reactive oxygen species, is systematically summarized. The perspectives and challenges of cascade strategy for drug delivery are also discussed.

Fluorescent nanoparticles with ultralow chromophore loading for long-term tumor-targeted imaging

Recently, organic dyes with aggregation-induced emission (AIE) have attracted much attention in bioimaging and diagnostics. Relatively, the application of traditional dyes has diminished because of aggregation-caused quenching (ACQ). In this work, we compare the imaging ability of nanoparticle formulations of these two kinds of dyes. Boron dipyrromethene (BODIPY) was chosen as a representative of the ACQ dyes, and an aggregation-induced emission (AIE) dye BPMT was used for comparison. BODIPY and BPMT were entrapped into PEG_5k-PLA_10k to form BODIPY-loaded NPs (BNPs) and BPMT-loaded NPs (ANPs), respectively. In vivo and ex vivo imaging demonstrated that BNP1 with ultralow BODIPY load (0.07%) can effectively accumulate in tumor tissues and enable long-term noninvasive imaging. In contrast, ANP4 with high BPMT load (1.6%) has poor bioimaging ability. In general, our work has certain reference significance for the application of ACQ dyes and AIEgens in bioimaging, diagnostics, and theranostics. STATEMENT OF SIGNIFICANCE: In this work, Boron dipyrromethene (BODIPY) was chosen as a representative of ACQ dyes. As a control, (Z)-2-(4'-(9H-carbazol-9-yl)-[1,1'-biphenyl]-4-yl)-3-(7-(4-(bis(4methoxyphenyl)amino) phenyl) benzo[c] [1,2,5] thiadiazol-4-yl) acrylonitrile (BPMT) was selected as an aggregation-induced emission (AIE) dye. BODIPY and BPMT was entrapped into PEG5k-PLA10k to form BODIPY-loaded NPs (BNPs) and BPMT-loaded NPs (ANPs), respectively. In vivo and ex vivo imaging demonstrated that BNP1 with ultralow BODIPY load (0.07%) can effectively accumulate in tumor tissues and realize long-term noninvasive imaging. The weaknesses of ACQ effect can be converted into advantages by skillful use of nanotechnology, which can not only save the cost but also realize high efficiency targeted cancer imaging.

Biological Evaluation of Naproxen-Dehydrodipeptide Conjugates with Self-Hydrogelation Capacity as Dual LOX/COX Inhibitors

The use of peptide-drug conjugates is emerging as a powerful strategy for targeted drug delivery. Previously, we have found that peptides conjugated to a non-steroidal anti-inflammatory drug (NSAID), more specifically naproxen-dehydrodipeptide conjugates, readily form nanostructured fibrilar supramolecular hydrogels. These hydrogels were revealed as efficacious nano-carriers for drug delivery applications. Moreover, the incorporation of superparamagnetic iron oxide nanoparticles (SPIONs) rendered the hydrogels responsive to external magnetic fields, undergoing gel-to-solution phase transition upon remote magnetic excitation. Thus, magnetic dehydrodipeptide-based hydrogels may find interesting applications as responsive Magnetic Resonance Imaging (MRI) contrast agents and for magnetic hyperthermia-triggered drug-release applications. Supramolecular hydrogels where the hydrogelator molecule is endowed with intrinsic pharmacological properties can potentially fulfill a dual function in drug delivery systems as (passive) nanocariers for incorporated drugs and as active drugs themselves. In this present study, we investigated the pharmacological activities of a panel of naproxen-dehydrodipeptide conjugates, previously studied for their hydrogelation ability and as nanocarriers for drug-delivery applications. A focused library of dehydrodipeptides, containing N-terminal canonical amino acids (Phe, Tyr, Trp, Ala, Asp, Lys, Met) N-capped with naproxen and linked to a C-terminal dehydroaminoacid (ΔPhe, ΔAbu), were evaluated for their anti-inflammatory and anti-cancer activities, as well as for their cytotoxicity to non-cancer cells, using a variety of enzymatic and cellular assays. All compounds except one were able to significantly inhibit lipoxygenase (LOX) enzyme at a similar level to naproxen. One of the compounds 4 was able to inhibit the cyclooxygenase-2 (COX-2) to a greater extent than naproxen, without inhibiting cyclooxygenase-1 (COX-1), and therefore is a potential lead in the search for selective COX-2 inhibitors. This hydrogelator is a potential candidate for dual COX/LOX inhibition as an optimised strategy for treating inflammatory conditions.

Collaborative assembly of doxorubicin and galactosyl diblock glycopolymers for targeted drug delivery of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) patients suffer from severe pain due to the serious systemic side effects and low efficiency of chemotherapeutic drugs, and it is important to develop novel drug delivery systems to circumvent these issues. In this study, a series of galactose-based glycopolymers, poly(N-(prop-2-enoyl)-β-d-galactopyranosylamine)-b-poly(N-isopropyl acrylamide) (pGal(OH)-b-pNIPAA), were prepared through a sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and tetrabutylammonium hydroxide (TBAOH)-mediated removal of acetyl groups. Hydrophilic doxorubicin hydrochloride was introduced to undergo collaborative assembly with poly(N-(prop-2-enoyl)-β-d-peracetylated galactosamine)-b-poly(N-isopropyl acrylamide) (pGal(Ac)-b-pNIPAA) via TBAOH treatment. pGal-b-pNIPAA/doxorubicin (DOX) delivery nanoparticles (GND NPs) formed by collaborative assembly were fully characterized by NMR, TEM and FT-IR, indicating the well-controlled formation of particles with uniform size and high efficiency in terms of drug loading and encapsulation compared with conventional adsorption methods. Meanwhile, the GND NPs were observed to be rapidly disintegrated under acidic conditions and resulted in an increased release of DOX. Cellular experiments showed that pGal-b-pNIPAA/DOX is apparently an asialoglycoprotein receptor (ASGPR)-mediated target of HCC, resulting in enhanced cellular uptake to HepG2 cells and anti-tumor efficacy in vitro. Furthermore, GND NPs III exerted more sustainable and effective anti-tumor effects compared to free DOX on a transgenic zebrafish TO(Kras^G12V) model in vivo. These results indicated that the biocompatible nanomaterials developed by collaborative assembly with galactosyl diblock glycopolymers and DOX may serve as a promising candidates for targeting therapy of HCC.

Glutathione Depletion in a Benign Manner by MoS2 -Based Nanoflowers for Enhanced Hypoxia-Irrelevant Free-Radical-Based Cancer Therapy

Tumor hypoxia significantly diminishes the efficacy of reactive oxygen species (ROS)-based therapy, mainly because the generation of ROS is highly oxygen dependent. Recently reported hypoxia-irrelevant radical initiators (AIBIs) exhibit promising potential for cancer therapy under different oxygen tensions. However, overexpressed glutathione (GSH) in cancer cells would potently scavenge the free radicals produced from AIBI before their arrival to the specific site and dramatically limit the therapeutic efficacy. A synergistic antitumor platform (MoS₂ @AIBI-PCM nanoflowers) is constructed by incorporating polyethylene-glycol-functionalized molybdenum disulfide (PEG-MoS₂ ) nanoflowers with azo initiator and phase-change material (PCM). Under near-infrared laser (NIR) irradiation, the photothermal feature of PEG-MoS₂ induces the decomposition of AIBI to produce free radicals. Furthermore, PEG-MoS₂ can facilitate GSH oxidation without releasing toxic metal ions, greatly promoting tumor apoptosis and avoiding the introduction of toxic metal ions. This is the first example of the use of intelligent MoS₂ -based nanoflowers as a benign GSH scavenger for enhanced cancer treatment.

Robust Photothermal Nanodrugs Based on Covalent Assembly of Nonpigmented Biomolecules for Antitumor Therapy

Photothermal nanodrugs based on biomolecules are critically important for advancing photothermal therapy (PTT). However, constructing photothermal nanodrugs from biomolecules is highly challenging because most biomolecules are inherently nonpigmented. Herein, we synthesize well-defined, uniform photothermal nanodrugs through a covalent assembly approach by using nonpigmented peptides and iridoids as building blocks. The resulting photothermal nanodrugs show broad absorption from the UV to the near-infrared region, high photothermal conversion efficiency along with robust photostability, and selective tumor accumulation, leading to highly efficient tumor ablation via PTT. This work represents the first example of photothermal nanodrugs that can be constructed by using nonpigmented biomolecules as building blocks and thus will conceivably promote the preclinical evaluation and clinical translation of PTT.

Mitochondria-Targeting Thermosensitive Initiator with Enhanced Anticancer Efficiency

As one of the most important organelles in cells, the mitochondrion has been reported to exhibit higher temperatures and is vulnerable to free radicals, especially in cancer cells. Here, we report on the use of a mitochondria-targeted thermosensitive radical initiator for cancer cell killing. The thermal-sensitive radical initiator, V044 (2,2'-azobis [2-(2-imidazolin-2-yl)propane]dihydrochloride), was applied as a radical source, which was linked with a mitochondrial targeting moiety, triphenylphosphine (TPP), to construct the mitochondria-targeting radical initiator (TPPV). Mitochondria were applied as the endogenous thermal source of cells, which accelerated the free radical generation of TPPV. Results showed that TPPV could effectively generate free radicals in the mitochondrial area, and the released free radicals effectively damaged mitochondria, exhibiting an enhanced anticancer efficiency. This therapy based on endogenous mitochondrial heat avoids tissue penetration limits and offers a target for mitochondria-targeting systems.