Structural and Property Characterizations of Dual-Responsive Core-Shell Tecto Dendrimers for Tumor Penetration and Gene Delivery Applications.

Core-shell tecto dendrimers (CSTDs) with excellent physicochemical properties and good tumor penetration and gene transfection efficiency have been demonstrated to have the potential to replace high-generation dendrimers in biomedical applications. However, their characterization and related biological properties of CSTDs for enhanced tumor penetration and gene delivery still lack in-depth investigation. Herein, three types of dual-responsive CSTDs are designed for thorough physicochemical characterization and investigation of their tumor penetration and gene delivery efficiency. Three types of CSTDs are prepared through phenylborate ester bonds of phenylboronic acid (PBA)-decorated generation 5 (G5) poly(amidoamine) (PAMAM) dendrimers as cores and monose (galactose, glucose, or mannose)-conjugated G3 PAMAM dendrimers as shells and thoroughly characterized via NMR and other techniques. It is shown that the produced CSTDs display strong correlation signals between the PBA and monose protons, similar hydrodynamic diameters, and dual reactive oxygen species- and pH-responsivenesses. The dual-responsive CSTDs are proven to have structure-dependent tumor penetration property and gene delivery efficiency in terms of small interference RNA for gene silencing and plasmid DNA for gene editing, thus revealing a great potential for different biomedical applications.

Deep Tumor Penetration of CRISPR-Cas System for Photothermal-Sensitized Immunotherapy via Probiotics.

Since central cells are more malignant and aggressive in solid tumors, improving penetration of therapeutic agents and activating immunity in tumor centers exhibit great potential in cancer therapies. Here, polydopamine-coated Escherichia coli Nissle 1917 (EcN) bearing CRISPR-Cas9 plasmid-loaded liposomes (Lipo-P) are applied for enhanced immunotherapy in deep tumors through activation of innate and adaptive immunity simultaneously. After accumulation in the tumor center through hypoxia targeting, Lipo-P could be detached under the reduction of reactive oxygen species (ROS)-responsive linkers, lowering the thermal resistance of cancer cells via Hsp90α depletion. Owing to that, heating induced by polydopamine upon near-infrared irradiation could achieve effective tumor ablation. Furthermore, mild photothermal therapy induces immunogenic cell death, as bacterial infections in tumor tissues trigger innate immunity. This bacteria-assisted approach provides a promising photothermal-sensitized immunotherapy in deep tumors.

Nitric Oxide-Loaded Bioinspired Lipoprotein Normalizes Tumor Vessels To Improve Intratumor Delivery and Chemotherapy of Albumin-Bound Paclitaxel Nanoparticles.

The disorganized vasculatures in tumors represent a substantial challenge of intratumor nanomedicine delivery to exert the anticancer effects. Herein, we rationally designed a glutathione (GSH)-activated nitric oxide (NO) donor loaded bioinspired lipoprotein system (NO-BLP) to normalize tumor vessels and then promote the delivery efficiency of sequential albumin-bound paclitaxel nanoparticles (PAN) in tumors. NO-BLP exhibited higher tumor accumulation and deeper penetration versus the counterpart liposomal formulation (NO-Lipo) in 4T1 breast cancer tumors, thus producing notable vascular normalization efficacy and causing a 2.33-fold increase of PAN accumulation. The sequential strategy of NO-BLP plus PAN resulted in an 81.03% inhibition of tumor growth in 4T1 tumors, which was better than the NO-BLP monotherapy, PAN monotherapy, and the counterpart NO-Lipo plus PAN treatment. Therefore, the bioinspired lipoprotein of NO-BLP provides an encouraging platform to normalize tumor vessels and promote intratumor delivery of nanomedicines for effective cancer treatment.

Transcytosis-Inducing Multifunctional Albumin Nanomedicines with Deep Penetration Ability for Image-Guided Solid Tumor Treatment.

Transcytosis is an active transcellular transportation pathway that has garnered interest for overcoming the limited deep penetration of nanomedicines in solid tumors. In this study, a charge-convertible nanomedicine that facilitates deep penetration into solid tumors via transcytosis is designed. It is an albumin-based calcium phosphate nanomedicine loaded with IR820 (mAlb-820@CaP) for high-resolution photoacoustic imaging and enhanced photothermal therapy. Biomineralization on the surface stabilizes the albumin-IR820 complex during circulation and provides calcium ions (Ca2+ ) for tissue penetration on degradation in an acidic environment. pH-triggered transcytosis of the nanomedicine enabled by caveolae-mediated endocytosis and calcium ion-induced exocytosis in 2D cellular, 3D spheroid, and in vivo tumor models is demonstrated. Notably, the extravasation and penetration ability of the nanomedicine is observed in vivo using a high-resolution photoacoustic system, and nanomedicine shows the most potent photothermal antitumor effect in vivo. Overall, the strategy provides a versatile theragnosis platform for both noninvasive photoacoustic imaging and high therapeutic efficiency resulting from deep penetration of nanomedicine.

Engineered Organic Nanorockets with Light-Driven Ultrafast Transportability for Antitumor Therapy.

Nanomedicines confront various complicated physiological barriers limiting the accumulation and deep penetration in the tumor microenvironment, which seriously restricts the efficacy of antitumor therapy. Self-propelled nanocarriers assembled with kinetic engines can translate external energy into orientated motion for tumor penetration. However, achieving a stable ultrafast permeability at the tumor site remains challenging. Here, sub-200 nm photoactivated completely organic nanorockets (NRs), with asymmetric geometry conveniently assembled from photothermal semiconducting polymer payload and thermo-driven macromolecular propulsion through a straightforward nanoprecipitation process, are presented. The artificial NRs can be remotely manipulated by 808 nm near-infrared light to trigger the photothermal conversion and Curtius rearrangement reaction within the particles for robustly pushing nitrogen out into the solution. Such a two-stage light-to-heat-to-chemical energy transition effectively powers the NRs for an ultrafast (≈300 µm s-1 ) and chemical medium-independent self-propulsion in the liquid media. That endows the NRs with high permeability against physiological barriers in the tumor microenvironment to directionally deliver therapeutic agents to target lesions for elevating tumor accumulation, deep penetration, and cellular uptake, resulting in a significant enhancement of antitumor efficacy. This work will inspire the design of advanced kinetic systems for powering intelligent nanomachines in biomedical applications.

Detachable MOF-Based Core/Shell Nanoreactor for Cancer Dual-Starvation Therapy With Reversing Glucose and Glutamine Metabolisms.

Tumor-dependent glucose and glutamine metabolisms are essential for maintaining survival, while the accordingly metabolic suppressive therapy is limited by the compensatory metabolism and inefficient delivery efficiency. Herein, a functional metal-organic framework (MOF)-based nanosystem composed of the weakly acidic tumor microenvironment-activated detachable shell and reactive oxygen species (ROS)-responsive disassembled MOF nanoreactor core is designed to co-load glycolysis and glutamine metabolism inhibitors glucose oxidase (GOD) and bis-2-(5-phenylacetmido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES) for tumor dual-starvation therapy. The nanosystem excitingly improves tumor penetration and cellular uptake efficiency via integrating the pH-responsive size reduction and charge reversal and ROS-sensitive MOF disintegration and drug release strategy. Furthermore, the degradation of MOF and cargoes release can be self-amplified via additional self-generation H2 O2 mediated by GOD. Last, the released GOD and BPTES collaboratively cut off the energy supply of tumors and induce significant mitochondrial damage and cell cycle arrest via simultaneous restriction of glycolysis and compensatory glutamine metabolism pathways, consequently realizing the remarkable triple negative breast cancer killing effect in vivo with good biosafety via the dual starvation therapy.

Effect of Polyplex Size on Penetration into Tumor Spheroids.

Ovarian cancer is one of the most lethal gynecological cancers in the world. In recent years, nucleic acid (NA)-based formulations have been shown to be promising treatments for ovarian cancer, including tumor nodules. However, gene therapy is not that far advanced in clinical reality due to unfavorable physicochemical properties of the NAs, such as high molecular weight, poor cellular uptake, rapid degradation by nucleases, etc. One of the strategies used to overcome these drawbacks is the complexation of anionic NAs via electrostatic interactions with cationic polymers, resulting in the formation of so-called polyplexes. In this work, the role of the size of pDNA and siRNA polyplexes on their penetration into ovarian-cancer-based tumor spheroids was investigated. For this, a methoxypoly(ethylene glycol) poly(2-(dimethylamino)ethyl methacrylate) (mPEG-pDMAEMA) diblock copolymer was synthesized as a polymeric carrier for NA binding and condensation with either plasmid DNA (pDNA) or short interfering RNA (siRNA). When prepared in HEPES buffer (10 mM, pH 7.4) at a nitrogen/phosphate (N/P) charge ratio of 5 and pDNA polyplexes were formed with a size of 162 ± 11 nm, while siRNA-based polyplexes displayed a size of 25 ± 2 nm. The polyplexes had a slightly positive zeta potential of +7-8 mV in the same buffer. SiRNA and pDNA polyplexes were tracked in vitro into tumor spheroids, resembling in vivo avascular ovarian tumor nodules. For this purpose, reproducible spheroids were obtained by coculturing ovarian carcinoma cells with primary mouse embryonic fibroblasts in different ratios (5:2, 1:1, and 2:5). Penetration studies revealed that after 24 h of incubation, siRNA polyplexes were able to penetrate deeper into the homospheroids (composed of only cancer cells) and heterospheroids (cancer cells cocultured with fibroblasts) compared to pDNA polyplexes which were mainly located in the rim. The penetration of the polyplexes was slowed when increasing the fraction of fibroblasts present in the spheroids. Furthermore, in the presence of serum siRNA polyplexes encoding for luciferase showed a high cellular uptake in 2D cells resulting in ∼50% silencing of luciferase expression. Taken together, these findings show that self-assembled small siRNA polyplexes have good potential as a platform to test ovarian tumor nodulus penetration..

A highly stable human single-domain antibody-drug conjugate exhibits superior penetration and treatment of solid tumors.

The inefficient tumor penetration of therapeutic antibodies has hampered their effective use in treating solid tumors. Here, we report the identification of a fully human single-domain antibody (UdAb), designated as n501, targeting the oncofetal antigen 5T4. The high-resolution crystal structure indicates that n501 adopts a compact structure very similar to that of camelid nanobodies, and binds tightly to all eight leucine-rich repeats of 5T4. Furthermore, the UdAb n501 exhibits exceptionally high stability, with no apparent activity changes over 4 weeks of storage at various temperatures. Importantly, the UdAb-based antibody-drug conjugate (n501-SN38) showed much deeper tumor penetration, significantly higher tumor uptake, and faster accumulation at tumor sites than conventional IgG1-based antibody-drug conjugate (m603-SN38), resulting in improved tumor inhibition. These results highlight the potential of UdAb-based antibody-drug conjugates as a potential class of antitumor therapeutics with characteristics of high stability and strong tumor penetration for the effective treatment of solid tumors.

Multistage Systemic and Cytosolic Protein Delivery for Effective Cancer Treatment.

Current clinical applications of protein therapy are largely limited to systemically accessible targets in vascular or extracellular areas. Major obstacles to the widespread application of protein therapeutics in cancer treatment include low membrane permeability and endosomal entrapment. Herein, we report a multistage nanoparticle (NP) strategy for systemic and cytosolic protein delivery to tumor cells, by encapsulating a protein conjugate, tetra-guanidinium (TG)-modified saporin, into tumor microenvironment (TME) pH-responsive polymeric NPs. Upon reaching the tumor site after systemic circulation, the polymeric NPs respond rapidly to the acidic tumor microenvironment and release the TG-saporin conjugates, which penetrate the tumor tissue and enter into tumor cells via TG-mediated cytosolic transportation. The TG-saproin NPs showed potent inhibition of lung cancer cell growth in vitro and in vivo. We expect that this multistage NP delivery strategy with long blood circulation, deep tumor penetration, and efficient cytosolic transport may be applicable to various therapeutic proteins for effective cancer treatment.

ROS-Responsive Nanocomplex of aPD-L1 and Cabazitaxel Improves Intratumor Delivery and Potentiates Radiation-Mediated Antitumor Immunity.

Despite the promising benefits of immune checkpoint inhibitors (ICIs) in clinical cancer treatments, the therapeutic efficacy is largely restricted by low antitumor immunity and limited intratumor delivery in solid tumors. Herein, we designed a reactive oxygen species (ROS)-responsive albumin nanocomplex of antiprogrammed cell death receptor ligand 1 (aPD-L1) and cabazitaxel (RAN-PC), which exhibited prominent tumor accumulation and intratumor permeation in 4T1 tumors. Compared with the negative control, the RAN-PC + radiation treatment (RAN-PC+X) produced a 3.61- and 5.10-fold enhancement in CD3+CD8+ T cells and the interferon (IFN)-γ-expressing subtype, respectively, and notably reduced versatile immunosuppressive cells. Moreover, RAN-PC+X treatment resulted in notable retardation of tumor growth, with a 78.97% inhibition in a 4T1 breast tumor model and a 90.30% suppression in a CT-26 colon tumor model. Therefore, the ROS-responsive albumin nanocomplex offers an encouraging platform for ICIs with prominent intratumor delivery capacity for cancer immunotherapy.

Monensin Enhanced Generation of Extracellular Vesicles as Transfersomes for Promoting Tumor Penetration of Pyropheophorbide-a from Fusogenic Liposome.

The current state of antitumor nanomedicines is severely restricted by poor penetration in solid tumors. It is indicated that extracellular vesicles (EVs) secreted by tumor cells can mediate the intercellular transport of antitumor drug molecules in the tumor microenvironment. However, the inefficient generation of EVs inhibits the application of this approach. Herein, we construct an EV-mediated self-propelled liposome containing monensin as the EV secretion stimulant and photosensitizer pyropheophorbide-a (PPa) as a therapeutic agent. Monensin and PPa are first transferred to the tumor plasma membrane with the help of membrane fusogenic liposomes. By hitchhiking EVs secreted by the outer tumor cells, both drugs are layer-by-layer transferred into the deep region of a solid tumor. Particularly, monensin, serving as a sustainable booster, significantly amplifies the EV-mediated PPa penetration by stimulating EV production. Our results show that this endogenous EV-driven nanoplatform leads to deep tumor penetration and enhanced phototherapeutic efficacy.

Aminopeptidase N-Responsive Conjugates with Tunable Charge-Reversal Properties for Highly Efficient Tumor Accumulation and Penetration.

Tumor enzyme-responsive charge-reversal carriers can induce efficient transcytosis and lead to efficient tumor infiltration and potent anticancer efficacy. However, the correlations of molecular structure with charge-reversal property, tumor penetration, and drug delivery efficiency are unknown. Herein, aminopeptidase N (APN)-responsive conjugates were synthesized to investigate these correlations. We found that the monomeric unit structure and the polymer chain structure determined the enzymatic hydrolysis and charge-reversal rates, and accordingly, the transcytosis and tumor accumulation and penetration of the APN-responsive conjugates. The conjugate with moderate APN responsiveness balanced the in vitro transcytosis and in vivo overall drug delivery process and achieved the best tumor delivery efficiency, giving potent antitumor efficacy. This work provides new insight into the design of tumor enzyme-responsive charge-reversal nanomedicines for efficient cancer drug delivery.

Amphiphilic Metallodrug Assemblies with Red-Light-Enhanced Cellular Internalization and Tumor Penetration for Anticancer Phototherapy.

Metallodrugs are widely used in cancer treatment. The modification of metallodrugs with polyethylene glycol (PEGylation) prolongs blood circulation and improves drug accumulation in tumors; it represents a general strategy for drug delivery. However, PEGylation hinders cellular internalization and tumor penetration, which reduce therapeutic efficacy. Herein, the red-light-enhanced cellular internalization and tumor penetration of a PEGylated anticancer agent, PEGylated Ru complex (Ru-PEG), are reported upon. Ru-PEG contains a red-light-cleavable PEG ligand, anticancer Ru complex moiety, and fluorescent pyrene group for imaging and self-assembly. Ru-PEG self-assembles into vesicles that circulate in the bloodstream and accumulate in the tumors. Red-light irradiation induces dePEGylation and changes the Ru-PEG vesicles to large compound micelles with smaller diameters and higher zeta potentials, which enhance tumor penetration and cellular internalization. Red-light irradiation also generates intracellular 1 O2 , which induces the death of cancer cells. This work presents a new strategy to enhance the cellular internalization and tumor penetration of anticancer agents for efficient phototherapy.

Photoactivated Organic Nanomachines for Programmable Enhancement of Antitumor Efficacy.

Limited permeability in solid tumors significantly restricts the anticancer efficacy of nanomedicines. Light-driven nanomotors powered by photothermal converting engines are appealing carriers for directional drug delivery and simultaneous phototherapy. Nowadays, it is still a great challenge to construct metal-free photothermal nanomotors for a programmable anticancer treatment. Herein, one kind of photoactivated organic nanomachines is reported with asymmetric geometry assembled by light-to-heat converting semiconducting polymer engine and macromolecular anticancer payload through a straightforward nanoprecipitation process. The NIR-fueled polymer engine can be remotely controlled to power the nanomachines for light-driven thermophoresis in the liquid media and simultaneously thermal ablating the cancer cells. The great manipulability of the nanomachines allows for programming of their self-propulsion in the tumor microenvironment for effectively improving cellular uptake and tumor penetration of the anticancer payload. Taking the benefit from this behavior, a programmed treatment process is established at a low drug dose and a low photothermal temperature for significantly enhancing the antitumor efficacy.

Size-Transformable Bicomponent Peptide Nanoparticles for Deep Tumor Penetration and Photo-Chemo Combined Antitumor Therapy.

The suitable size of multifunctional nanomedicines strongly influences their physicochemical properties and actions in biological systems, for example, prolonged blood circulation time, efficient tumor accumulation, and deep tumor penetration. However, it is still a great challenge to construct size-transformable nanoparticles (NPs) for both efficient accumulation and penetration throughout tumor tissue. Herein, a size-transformed multifunctional NP is developed through a simple bicomponent assembling strategy for enhanced tumor penetration and efficient photo-chemo combined antitumor therapy, due to the acidic tumor microenvironment and near infrared-laser irradiation induced size-shrink. This multifunctional bicomponent NP (PP NP) driven by electrostatic interaction is composed of negatively charged peptide amphiphile (PA1) and positively charged peptide prodrug (PA2). PP NPs (≈170 nm) have been proven to improve blood circulation time and stability in biological environments. Interestingly, PP NPs can reassemble small NPs (<30 nm) by responding to acidic tumor microenvironment and near-infrared laser irradiation, which facilitates deep tumor penetration and improves cellular internalization. By integrating fluorescence imaging, tumor targeting, deep tumor penetration, and combined photo-chemotherapy, PP NPs exhibit excellent in vivo antitumor efficacy. This study might provide an insight for developing a bicomponent assembling system with efficient tumor penetration and multimode for antitumor therapy.

Oral Nanomotor-Enabled Mucus Traverse and Tumor Penetration for Targeted Chemo-Sono-Immunotherapy against Colon Cancer.

The therapeutic outcomes of oral nanomedicines against colon cancer are heavily compromised by their lack of specific penetration into the internal tumor, favorable anti-tumor activity, and activation of anti-tumor immunity. Herein, hydrogen peroxide (H2 O2 )/ultrasound (US)-driven mesoporous manganese oxide (MnOx )-based nanomotors are constructed by loading mitochondrial sonosensitizers into their mesoporous channels and orderly dual-functionalizing their surface with silk fibroin and chondroitin sulfate. The locomotory activities and tumor-targeting capacities of the resultant nanomotors (CS-ID@NMs) are greatly improved in the presence of H2 O2 and US irradiation, inducing efficient mucus-traversing and deep tumor penetration. The excess H2 O2 in the tumor microenvironment (TME) is decomposed into hydroxyl radicals and oxygen by an Mn2+ -mediated Fenton-like reaction, and the produced oxygen participates in sonodynamic therapy (SDT), yielding abundant singlet oxygen. The combined Mn2+ -mediated chemodynamic therapy and SDT cause effective ferropotosis of tumor cells and accelerate the release of tumor antigens. Importantly, animal experiments reveal that the treatment of combining oral hydrogel (chitosan/alginate)-embedding CS-ID@NMs and immune checkpoint inhibitors can simultaneously suppress the growth of primary and distal tumors through direct killing, reversion of immunosuppressive TME, and potentiation of systemic anti-tumor immunity, demonstrating that the CS-ID@NM-based platform is a robust oral system for synergistic treatment of colon cancer.

Deep Tumor Penetrating Gold Nano-Adjuvant for NIR-II-Triggered In Situ Tumor Vaccination.

Local tumor photothermal treatment with the near-infrared light at the second window (NIR-II) is a promising strategy in triggering the in situ tumor vaccination (ISTV) for cancer therapy. However, limited penetration of photothermal agents within tumors seriously limits their spatial effect in generating sufficient tumor-associated antigens, a key factor to the success of ISTV. In this study, a nano-adjuvant system is fabricated based on the NIR-II-absorbable gold nanostars decorated with hyaluronidases and immunostimulatory oligodeoxynucleotides CpG for ISTV. The nano-adjuvant displays a deep tumor penetration capacity via loosening the dense extracellular matrix of tumors. Upon NIR-II light irradiation, the nano-adjuvant significantly inhibits the tumor growth, induces a cascade of immune responses, generates an obvious adaptive immunity against the re-challenged cancers, boosts the abscopal effect, and completely inhibits the pulmonary metastases. The study highlights an advanced nano-adjuvant formulation featuring deep tumor penetration for NIR-II-triggered ISTV.

Deep-Penetrating Triple-Responsive Prodrug Nanosensitizer Actuates Efficient Chemoradiotherapy in Pancreatic Ductal Adenocarcinoma Models.

Chemoradiotherapy (CRT) is the most accepted treatment for locally advanced pancreatic ductal adenocarcinoma (PDAC) and can significantly improve the R0 resection rate. However, there are few long-term survivors after CRT. Although some polymer nanoparticles have shown potential in alleviating the dose-limiting toxicity and assisting the chemotherapy of PDAC, there are few efficient nanosensitizers (NS) available for CRT of this malignancy, especially in the context of its hypoxic nature. Herein, based on the biological features of PDAC, a γ-glutamyl transpeptidase (GGT)/glutathione (GSH)/hypoxia triple-responsive prodrug NS to overcome the biological barrier and microenvironmental limitations confronted by CRT in PDAC is developed. Due to triple-responsiveness, deep tumor penetration, GSH/hypoxia-responsive drug release/activation, and hypoxia-induced chemoradio-sensitization can be simultaneously achieved with this NS. As a result, tumor shrinkage after CRT with this NS can be observed in both subcutaneous and orthotopic PDAC models, foreshadowing its potential in clinical neoadjuvant CRT.

EGFR binding Fc domain-drug conjugates: stable and highly potent cytotoxic molecules mediate selective cell killing.

The exposition of cancer cells to cytotoxic doses of payload is fundamental for the therapeutic efficacy of antibody drug conjugates (ADCs) in solid cancers. To maximize payload exposure, tissue penetration can be increased by utilizing smaller-sized drug conjugates which distribute deeper into the tumor. Our group recently explored small human epidermal growth factor receptor 2 (HER2) targeting Fc antigen binding fragments (Fcabs) for ADC applications in a feasibility study. Here, we expand this concept using epidermal growth factor receptor (EGFR) targeting Fcabs for the generation of site-specific auristatin-based drug conjugates. In contrast to HER2-targeting Fcabs, we identified novel conjugation sites in the EGFR-targeting Fcab scaffold that allowed for higher DAR enzymatic conjugation. We demonstrate feasibility of resultant EGFR-targeting Fcab-drug conjugates that retain binding to half-life prolonging neonatal Fc receptor (FcRn) and EGFR and show high serum stability as well as target receptor mediated cell killing at sub-nanomolar concentrations. Our results emphasize the applicability of the Fcab format for the generation of drug conjugates designed for increased penetration of solid tumors and potential FcRn-driven antibody-like pharmacokinetics.

Size-changeable nanoprobes for the combined radiotherapy and photodynamic therapy of tumor.

PURPOSE: Radiation therapy (RT) and photodynamic therapy (PDT) are promising while challenging in treating tumors. The potential radiation resistance of tumor cells and side effects to healthy tissues restrict their clinical treatment efficacy. Effective delivery of therapeutic agents to the deep tumor tissues would be available for tumor-accurate therapy and promising for the tumor therapy. Thus, developing nanoprobes with effectively delivering radiotherapy sensitizers and photosensitizers to the interior of tumors is needed for the accurate combined RT and PDT of tumor. METHODS: The size-changeable nanoprobes of Gd2O3@BSA-BSA-Ce6 (BGBC) were synthesized with a crosslinking method. Magnetic resonance imaging (MRI) and in vivo near-infrared (NIR) imaging were measured to evaluate the nanoprobes' tumor accumulation and intratumor penetration effect. The tumor suppression effect of combined RT and PDT with these nanoprobes was also studied for the 4T1 bearing Balb/c mice. RESULTS: The nanoprobes BGBC showed high tumor accumulation and disintegrated into small particles responding to the photo-irradiation-produced reactive oxygen species (ROS), allowing for tumor penetration. Abundant radiotherapy sensitizers and photosensitizers were delivered to the deep tumor tissues, which is available for the accurate therapy of tumor. In addition, the BGBC displayed outstanding MRI and fluorescence imaging effects for evaluating the biodistribution and tumor suppression effect of nanoprobes. Consequently, significant tumor suppression effect was obtained based on the accurate tumor treatment with the combined RT and PDT. CONCLUSION: The designed size-changeable nanoprobes BGBC showed excellent tumor accumulation and deep tumor penetration, resulting in a significant tumor suppression effect based on the combined RT and PDT. This study provides a novel strategy for dual delivery of radiotherapy sensitizers and photosensitizers into the deep tumor tissues and is promising for the accurate theranostics of tumor.