Marginative Delivery-Mediated Extracellular Leakiness and T Cell Infiltration in Lung Metastasis by a Biomimetic Nanoraspberry.

T lymphocytes infiltrate the most devastating metastatic tumors for immunotherapy, allowing the potential for tumor metastasis suppression. However, tumor heterogeneity often restricts the infiltration of immune cells and possesses immune privilege that leads to protection from the immune attack, especially for invading metastatic clusters. Here, an exosome-camouflaged nanoraspberry (RB@Exo) doubling as a metastases-targeting agent and T cell-infiltration inducer that delivers an anticancer drug and energy is reported. The RB@Exo integrated an exosome-derived margination effect, and density-mediated nanoparticle-induced extracellular leakiness (nanoEL) exhibited more than a 70% colocalization of the RB@Exo to metastatic tumors in the lung in vivo. The release of cancer cell-cell interactions at the metastasis via nanoEL also elicited the 10-fold infiltration of T lymphocytes. The synergy of the T cell infiltration and photolytic effects transported by the RB@Exo deep into the metastatic tumors effectively inhibited the tumor in 60 days when treated with a single alternating magnetic field (AMF).

Graphene Quantum Dots-Mediated Theranostic Penetrative Delivery of Drug and Photolytics in Deep Tumors by Targeted Biomimetic Nanosponges.

Dual-targeted delivery of drugs and energy by nanohybrids can potentially alleviate side effects and improve the unique features required for precision medicine. To realize this aim, however, the hybrids which are often rapidly removed from circulation and the piled up tumors periphery near the blood vessels must address the difficulties in low blood half-lives and tumor penetration. In this study, a sponge-inspired carbon composites-supported red blood cell (RBC) membrane that doubles as a stealth agent and photolytic carrier that transports tumor-penetrative agents (graphene quantum dots and docetaxel (GQD-D)) and heat with irradiation was developed. The RBC-membrane enveloped nanosponge (RBC@NS) integrated to a targeted protein that accumulates in tumor spheroids via high lateral bilayer fluidity exhibits an 8-fold increase in accumulation compared to the NS. Penetrative delivery of GQDs to tumor sites is actuated by near-infrared irradiation through a one-atom-thick structure, facilitating penetration and drug delivery deep into the tumor tissue. The synergy of chemotherapy and photolytic effects was delivered by the theranostic GQDs deep into tumors, which effectively damaged and inhibited the tumor in 21 days when treated with a single irradiation. This targeted RBC@GQD-D/NS with the capabilities of enhanced tumor targeting, NIR-induced drug penetration into tumors, and thermal ablation for photolytic therapy promotes tumor suppression and exhibits potential for other biomedical applications.

Magnetoresponsive virus-mimetic nanocapsules with dual heat-triggered sequential-infected multiple drug-delivery approach for combinatorial tumor therapy.

Stimuli-responsive drug-delivery systems constitute an appealing approach to direct and restrict drug release spatiotemporally at the specific site of interest. However, it is difficult for most systems to affect every cancer cell in a tumor tissue due to the presence of the natural tumor barrier, leading to potential tumor recurrence. Here, core-shell magnetoresponsive virus-mimetic nanocapsules (VNs), which can infect cancer cells sequentially and double as a magnetothermal agent fabricated through anchoring iron oxide nanoparticles in a single-component protein (lactoferrin) shell, are reported. With large payload of hydrophilic/hydrophobic anticancer cargos, doxorubicin and palictaxel, VNs can simultaneously give a rapid drug release and intense heat while applying an external high-frequency magnetic field (HFMF). Furthermore, after being liberated from dead cells by HFMF manipulation, the constructive VNs can sequentially infect neighboring cancer cells and deliver sufficient therapeutic agents to next targeted sites. With high efficiency for sequential cell infections, VNs have successfully eliminated subcutaneous tumor after a combinatorial treatment. These results demonstrate that the VNs could be used for locally targeted, on-demand, magnetoresponsive chemotherapy/hyperthermia, combined with repeated cell infections for tumor therapy and other therapeutic applications.

Enhancement of cancer therapy efficacy by trastuzumab-conjugated and pH-sensitive nanocapsules with the simultaneous encapsulation of hydrophilic and hydrophobic compounds.

Trastuzumab-conjugated pH-sensitive double emulsion nanocapsules (DENCs) stabilized by a single-component Poly (vinyl alcohol) (PVA) with magnetic nanoparticles can be fabricated through a two-step double emulsion process; these nanocapsules can be used to encapsulate hydrophilic doxorubicin (Dox) and hydrophobic paclitaxel (PTX) simultaneously. When PMASH was attached to the shell of the DENCs, enhanced dual drug release of PTX/Dox was detected, specifically in intracellular acidic pH environments. The targeting ability of these Trastuzumab-conjugated DENCs was demonstrated with confocal images, which revealed a significantly elevated cellular uptake in HER-2 overexpressing SkBr3 cells. More importantly, an intravenous injection of this co-delivery system followed by magnetic targeting (MT) chemotherapy suppressed cancer growth in vivo more efficiently than the delivery of either PTX or Dox alone. The integration of the functionalities makes this combination therapy system a powerfully new tool for in vitro/in vivo cancer therapy, especially for in HER-2 positive cancers. FROM THE CLINICAL EDITOR: Trastuzumab-conjugated pH-sensitive nanocapsules were used in this study for simultaneous targeted delivery of hydrophobic (PTX) and hydrophilic (Dox) anti-cancer agents to HER-2 positive cancer cells. Additional use of magnetic targeting demonstrated superior efficacy of this delivery system compared to PTX or Dox alone.

Tumor-activated targetable photothermal chemotherapy using IR780/zoledronic acid-containing hybrid polymeric nanoassemblies with folate modification to treat aggressive breast cancer.

To effectively treat aggressive breast cancer by tumor-activated targetable photothermal chemotherapy, in this work, folate (FA)-modified hybrid polymeric nanoassemblies (HPNs) with a poly(ethylene glycol) (PEG)-detachable capability are developed as vehicles for tumor-targeted co-delivery of IR780, a lipophilic photothermal reagent, and zoledronic acid (ZA), a hydrophilic chemotherapy drug. Through hydrophobic interaction-induced co-assembly, IR780 molecules and ZA/poly(ethylenimine) (PEI) complexes were co-encapsulated into a poly(lactic-co-glycolic acid) (PLGA)-rich core stabilized by the amphiphilic FA-modified D-α-tocopheryl poly(ethylene glycol) succinate (FA-TPGS) and acidity-sensitive PEG-benzoic imine-octadecane (C18) (PEG-b-C18) conjugates. The developed FA-ZA/IR780@HPNs with high ZA and IR780 payloads not only showed excellent colloidal stability in a serum-containing milieu, but also promoted IR780-based photostability and photothermal conversion efficiency. Furthermore, for FA-ZA/IR780@HPNs under simulated physiological conditions, the premature leakage of IR780 and ZA molecules was remarkably declined. In a mimetic acidic tumor microenvironment, the uptake of FA-ZA/IR780@HPNs by FA receptor-overexpressed 4T1 breast cancer cells was remarkably promoted by PEG detachment combined with FA receptor-mediated endocytosis, thus effectively hindering migration of cancer cells and augmenting the anticancer efficacy of photothermal chemotherapy. Notably, the in vivo studies demonstrated that the FA-ZA/IR780@HPNs largely deposited at 4T1 tumor sites and profoundly suppressed tumor growth and metastasis without severe systemic toxicity upon near infrared (NIR)-triggered IR780-mediated hyperthermia integrated with ZA chemotherapy. This work presents a practical strategy to treat aggressive breast tumors with tumor-triggered targetable photothermal chemotherapy using FA-ZA/IR780@HPNs.

A Self-Cascade Penetrating Brain Tumor Immunotherapy Mediated by Near-Infrared II Cell Membrane-Disrupting Nanoflakes via Detained Dendritic Cells.

Immunotherapy can potentially suppress the highly aggressive glioblastoma (GBM) by promoting T lymphocyte infiltration. Nevertheless, the immune privilege phenomenon, coupled with the generally low immunogenicity of vaccines, frequently hampers the presence of lymphocytes within brain tumors, particularly in brain tumors. In this study, the membrane-disrupted polymer-wrapped CuS nanoflakes that can penetrate delivery to deep brain tumors via releasing the cell-cell interactions, facilitating the near-infrared II (NIR II) photothermal therapy, and detaining dendritic cells for a self-cascading immunotherapy are developed. By convection-enhanced delivery, membrane-disrupted amphiphilic polymer micelles (poly(methoxypoly(ethylene glycol)-benzoic imine-octadecane, mPEG-b-C18) with CuS nanoflakes enhances tumor permeability and resides in deep brain tumors. Under low-power NIR II irradiation (0.8 W/cm2), the intense heat generated by well-distributed CuS nanoflakes actuates the thermolytic efficacy, facilitating cell apoptosis and the subsequent antigen release. Then, the positively charged polymer after hydrolysis of the benzoic-imine bond serves as an antigen depot, detaining autologous tumor-associated antigens and presenting them to dendritic cells, ensuring sustained immune stimulation. This self-cascading penetrative immunotherapy amplifies the immune response to postoperative brain tumors but also enhances survival outcomes through effective brain immunotherapy.

PEGylated chitosan-coated nanophotosensitizers for effective cancer treatment by photothermal-photodynamic therapy combined with glutathione depletion.

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has emerged as a promising strategy for cancer treatment. However, the poor photostability and photothermal conversion efficiency (PCE) of organic small-molecule photosensitizers, and the intracellular glutathione (GSH)-mediated singlet oxygen scavenging largely decline the antitumor efficacy of PTT and PDT. Herein, a versatile nanophotosensitizer (NPS) system is developed by ingenious incorporation of indocyanine green (ICG) into the PEGylated chitosan (PEG-CS)-coated polydopamine (PDA) nanoparticles via multiple π-π stacking, hydrophobic and electrostatic interactions. The PEG-CS-covered NPS showed prominent colloidal and photothermal stability as well as high PCE (ca 62.8 %). Meanwhile, the Michael addition between NPS and GSH can consume GSH, thus reducing the GSH-induced singlet oxygen scavenging. After being internalized by CT26 cells, the NPS under near-infrared laser irradiation produced massive singlet oxygen with the aid of thermo-enhanced intracellular GSH depletion to elicit mitochondrial damage and lipid peroxide formation, thus leading to ferroptosis and apoptosis. Importantly, the combined PTT and PDT delivered by NPS effectively inhibited CT26 tumor growth in vivo by light-activated intense hyperthermia and redox homeostasis disturbance. Overall, this work presents a new tactic of boosting antitumor potency of ICG-mediated phototherapy by PEG-CS-covered NPS.

Lung metastasis-Harnessed in-Situ adherent porous organic nanosponge-mediated antigen capture for A self-cascaded detained dendritic cells and T cell infiltration.

The infiltration of cytotoxic T lymphocytes promises to suppress the most irresistible metastatic tumor for immunotherapy, yet immune privilege and low immunogenic responses in these aggressive clusters often restrict lymphocyte recruitment. Here, an in situ adherent porous organic nanosponge (APON) doubles as organ selection agent and antigen captor to overcome immune privilege is developed. With selective organ targeting, the geometric effect of APON composed of disc catechol-functionalized covalent organic framework (COF) boosts the drug delivery to lung metastases. Along with a self-cascaded immune therapy, the therapeutic agents promote tumor release of damage-associated molecular patterns (DAMPs), and then, in situ deposition of gels to capture these antigens. Furthermore, APON with catechol analogs functions as a reservoir of antigens and delivers autologous DAMPs to detain dendritic cells, resulting in a sustained enhancement of immunity. This disc sponges (APON) at lung metastasis as antigen reservoirs and immune modulators effectively suppress the tumor in 60 days and enhanced the survival rate.

Revealing intact neuronal circuitry in centimeter-sized formalin-fixed paraffin-embedded brain.

Tissue-clearing and labeling techniques have revolutionized brain-wide imaging and analysis, yet their application to clinical formalin-fixed paraffin-embedded (FFPE) blocks remains challenging. We introduce HIF-Clear, a novel method for efficiently clearing and labeling centimeter-thick FFPE specimens using elevated temperature and concentrated detergents. HIF-Clear with multi-round immunolabeling reveals neuron circuitry regulating multiple neurotransmitter systems in a whole FFPE mouse brain and is able to be used as the evaluation of disease treatment efficiency. HIF-Clear also supports expansion microscopy and can be performed on a non-sectioned 15-year-old FFPE specimen, as well as a 3-month formalin-fixed mouse brain. Thus, HIF-Clear represents a feasible approach for researching archived FFPE specimens for future neuroscientific and 3D neuropathological analyses.

Programmed antigen capture-harnessed dendritic cells by margination-hitchhiking lung delivery.

Adoptive T cells and immunotherapy suppress the most destructive metastatic tumors and prevent tumor recurrence by inducing T lymphocytes. However, the heterogeneity and immune privilege of invasive metastatic clusters often reduce immune cell infiltration and therapeutic efficacy. Here, the red blood cells (RBC)-hitchhiking mediated lung metastasis delivery of multi-grained iron oxide nanostructures (MIO) programming the antigen capture, dendritic cell harnessing, and T cell recruitment is developed. MIO is assembled to the surface of RBCs by osmotic shock-mediated fusion, and reversible interactions enable the transfer of MIO to pulmonary capillary endothelial cells by intravenous injection by squeezing RBCs at the pulmonary microvessels. RBC-hitchhiking delivery revealed that >65% of MIOs co-localized in tumors rather than normal tissues. In alternating magnetic field (AMF)-mediated magnetic lysis, MIO leads to the release of tumor-associated antigens, namely neoantigens and damage-associated molecular patterns. It also acted as an antigen capture agent-harnessed dendritic cells delivers these antigens to lymph nodes. By utilizing site-specific targeting, erythrocyte hitchhiker-mediated delivery of MIO to lung metastases improves survival and immune responses in mice with metastatic lung tumors.

Programmed T cells infiltration into lung metastases with harnessing dendritic cells in cancer immunotherapies by catalytic antigen-capture sponges.

T lymphocytes served as immune surveillance to suppress metastases by physically interacting with cancer cells. Whereas tumor immune privilege and heterogeneity protect immune attack, it limits immune cell infiltration into tumors, especially in invasive metastatic clusters. Here, a catalytic antigen-capture sponge (CAS) containing the catechol-functionalized copper-based metal organic framework (MOF) and chloroquine (CQ) for programming T cells infiltration is reported. The intravenously injected CAS accumulates at the tumor via the folic acid-mediated target and margination effect. In metastases, Fenton-like reaction induced by copper ions of CAS disrupts the intracellular redox potential, i.e., chemodynamic therapy (CDT), thereby reducing glutathione (GSH) levels. Furthermore, CQ helps inhibit autophagy by inducing lysosomal deacidification during CDT. This process leads to the breakdown of self-defense mechanisms, which exacerbates cytotoxicity. The therapies promote the liberation of tumor-associated antigens, such as neoantigens and damage-associated molecular patterns (DAMPs). Subsequently, the catechol groups present on CAS perform as antigen reservoirs and transport the autologous tumor-associated antigens to dendritic cells, resulting in prolonged immune activation. The CAS, which is capable of forming in-situ, serves as an antigen reservoir in CDT-mediated lung metastasis and leads to the accumulation of immune cells in metastatic clusters, thus hindering metastatic tumors.

In Situ Forming of Nitric Oxide and Electric Stimulus for Nerve Therapy by Wireless Chargeable Gold Yarn-Dynamos.

Endogenous signals, namely nitric oxide (NO) and electrons, play a crucial role in regulating cell fate as well as the vascular and neuronal systems. Unfortunately, utilizing NO and electrical stimulation in clinical settings can be challenging due to NO's short half-life and the invasive electrodes required for electrical stimulation. Additionally, there is a lack of tools to spatiotemporally control gas release and electrical stimulation. To address these issues, an "electromagnetic messenger" approach that employs on-demand high-frequency magnetic field (HFMF) to trigger NO release and electrical stimulation for restoring brain function in cases of traumatic brain injury is introduced. The system comprises a NO donor (poly(S-nitrosoglutathione), pGSNO)-conjugated on a gold yarn-dynamos (GY) and embedded in an implantable silk in a microneedle. When subjected to HFMF, conductive GY induces eddy currents that stimulate the release of NO from pGSNO. This process significantly enhances neural stem cell (NSC) synapses' differentiation and growth. The combined strategy of using NO and electrical stimulation to inhibit inflammation, angiogenesis, and neuronal interrogation in traumatic brain injury is demonstrated in vivo.

Sustained Release of Nitric Oxide-Mediated Angiogenesis and Nerve Repair by Mussel-Inspired Adaptable Microreservoirs for Brain Traumatic Injury Therapy.

Traumatic brain injury (TBI) triggers inflammatory response and glial scarring, thus substantially hindering brain tissue repair. This process is exacerbated by the accumulation of activated immunocytes at the injury site, which contributes to scar formation and impedes tissue repair. In this study, a mussel-inspired nitric oxide-release microreservoir (MINOR) that combines the features of reactive oxygen species (ROS) scavengers and sustained NO release to promote angiogenesis and neurogenesis is developed for TBI therapy. The injectable MINOR fabricated using a microfluidic device exhibits excellent monodispersity and gel-like self-healing properties, thus allowing the maintenance of its structural integrity and functionality upon injection. Furthermore, polydopamine in the MINOR enhances cell adhesion, significantly reduces ROS levels, and suppresses inflammation. Moreover, a nitric oxide (NO) donor embedded into the MINOR enables the sustained release of NO, thus facilitating angiogenesis and mitigating inflammatory responses. By harnessing these synergistic effects, the biocompatible MINOR demonstrates remarkable efficacy in enhancing recovery in mice. These findings benefit future therapeutic interventions for patients with TBI.

Programmed Catalytic Therapy-Mediated ROS Generation and T-Cell Infiltration in Lung Metastasis by a Dual Metal-Organic Framework (MOF) Nanoagent.

Nano-catalytic agents actuating Fenton-like reaction in cancer cells cause intratumoral generation of reactive oxygen species (ROS), allowing the potential for immune therapy of tumor metastasis via the recognition of tumor-associated antigens. However, the self-defense mechanism of cancer cells, known as autophagy, and unsustained ROS generation often restricts efficiency, lowering the immune attack, especially in invading metastatic clusters. Here, a functional core-shell metal-organic framework nanocube (dual MOF) doubling as a catalytic agent and T cell infiltration inducer that programs ROS and inhibits autophagy is reported. The dual MOF integrated a Prussian blue (PB)-coated iron (Fe2+)-containing metal-organic framework (MOF, MIL88) as a programmed peroxide mimic in the cancer cells, facilitating the sustained ROS generation. With the assistance of Chloroquine (CQ), the inhibition of autophagy through lysosomal deacidification breaks off the self-defense mechanism and further improves the cytotoxicity. The purpose of this material design was to inhibit autophagy and ROS efficacy of the tumor, and eventually improve T cell recruitment for immune therapy of lung metastasis. The margination and internalization-mediated cancer cell uptake improve the accumulation of dual MOF of metastatic tumors in vivo. The effective catalytic dual MOF integrated dysfunctional autophagy at the metastasis elicits the ~3-fold recruitment of T lymphocytes. Such synergy of T cell recruitment and ROS generation transported by dual MOF during the metastases successfully suppresses more than 90% of tumor foci in the lung.

Rabies Virus Glycoprotein-Mediated Transportation and T Cell Infiltration to Brain Tumor by Magnetoelectric Gold Yarnballs.

T lymphocyte infiltration with immunotherapy potentially suppresses most devastating brain tumors. However, local immune privilege and tumor heterogeneity usually limit the penetration of immune cells and therapeutic agents into brain tumors, leading to tumor recurrence after treatment. Here, a rabies virus glycoprotein (RVG)-camouflaged gold yarnball (RVG@GY) that can boost the targeting efficiency at a brain tumor via dual hierarchy- and RVG-mediated spinal cord transportation, facilitating the decrease of tumor heterogeneity for T cell infiltration, is developed. Upon magnetoelectric irradiation, the electron current generated on the GYs activates the electrolytic penetration of palbociclib-loaded dendrimer (Den[Pb]) deep into tumors. In addition, the high-density GYs at brain tumors also induces the disruption of cell-cell interactions and T cell infiltration. The integration of the electrolytic effects and T cell infiltration promoted by drug-loaded RVG@GYs deep in the brain tumor elicits sufficient T cell numbers and effectively prolongs the survival rate of mice with orthotopic brain tumors.

Wireless charging-mediated angiogenesis and nerve repair by adaptable microporous hydrogels from conductive building blocks.

Traumatic brain injury causes inflammation and glial scarring that impede brain tissue repair, so stimulating angiogenesis and recovery of brain function remain challenging. Here we present an adaptable conductive microporous hydrogel consisting of gold nanoyarn balls-coated injectable building blocks possessing interconnected pores to improve angiogenesis and recovery of brain function in traumatic brain injury. We show that following minimally invasive implantation, the adaptable hydrogel is able to fill defects with complex shapes and regulate the traumatic brain injury environment in a mouse model. We find that placement of this injectable hydrogel at peri-trauma regions enhances mature brain-derived neurotrophic factor by 180% and improves angiogenesis by 250% in vivo within 2 weeks after electromagnetized stimulation, and that these effects facilitate neuron survival and motor function recovery by 50%. We use blood oxygenation level-dependent functional neuroimaging to reveal the successful restoration of functional brain connectivity in the corticostriatal and corticolimbic circuits.

Magnetic Responsive Release of Nitric Oxide from an MOF-Derived Fe3O4@PLGA Microsphere for the Treatment of Bacteria-Infected Cutaneous Wound.

Nitric oxide (NO) is an essential endogenous signaling molecule regulating multifaceted physiological functions in the (cardio)vascular, neuronal, and immune systems. Due to the short half-life and location-/concentration-dependent physiological function of NO, translational application of NO as a novel therapeutic approach, however, awaits a strategy for spatiotemporal control on the delivery of NO. Inspired by the magnetic hyperthermia and magneto-triggered drug release featured by Fe3O4 conjugates, in this study, we aim to develop a magnetic responsive NO-release material (MagNORM) featuring dual NO-release phases, namely, burst and steady release, for the selective activation of NO-related physiology and treatment of bacteria-infected cutaneous wound. After conjugation of NO-delivery [Fe(µ-S-thioglycerol)(NO)2]2 with a metal-organic framework (MOF)-derived porous Fe3O4@C, encapsulation of obtained conjugates within the thermo-responsive poly(lactic-co-glycolic acid) (PLGA) microsphere completes the assembly of MagNORM. Through continuous/pulsatile/no application of the alternating magnetic field (AMF) to MagNORM, moreover, burst/intermittent/slow release of NO from MagNORM demonstrates the AMF as an ON/OFF switch for temporal control on the delivery of NO. Under continuous application of the AMF, in particular, burst release of NO from MagNORM triggers an effective anti-bacterial activity against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). In addition to the magneto-triggered bactericidal effect of MagNORM against E. coli-infected cutaneous wound in mice, of importance, steady release of NO from MagNORM without the AMF promotes the subsequent collagen formation and wound healing in mice.

Nanocomposites with spatially separated functionalities for combined imaging and magnetolytic therapy.

Compact nanostructures with highly integrated functionalities are of considerable current interest to drug delivery, multimodality imaging, and electronic devices. A key challenge, however, is how to combine individual components together without interfering or sacrificing their original electronic and optical properties. Here, we demonstrate a new class of nanocomposites with spatially separated functionalities. We further demonstrate magnetic field modulated imaging and an innovative application of this technology in cancer cell treatment, magnetolytic therapy, based on magnetically controlled mechanical damage to cell membranes.

Stable Encapsulation of QD Barcodes with Silica Shells.

Quantum dot-doped mesoporous microbeads (QDMMs) are encapsulated with silica shells for enhanced chemical stability. The results show that a micro-emulsion procedure is highly efficient in coating QDMMs with polyvinyl alcohol (PVA), which is important in the subsequent deposition of a silica shell. Incorporation of fluorescent silane precursors allows direct observation of silica shells by fluorescence microscopy. The resulting silica coated QDMMs (QDMM@SiO(2)) exhibit remarkable stability against solvent-induced QD leaching and chemical-induced fluorescence quenching compared with uncoated QDMMs. Further development of this technology such as optimization of silica shell thickness, surface modification with non-fouling polymers, and conjugation with biomolecular probes will enable clinical translation of the optical barcoding technology for highly multiplexed detection and screening of genes and proteins.

Hybrid polymeric nanoparticles with high zoledronic acid payload and proton sponge-triggered rapid drug release for anticancer applications.

Zoledronic acid (ZA), a third-generation nitrogen-heterocycle-containing bisphosphonate, has been frequently used as an anti-resorptive agent to treat cancer-involved hypercalcemia and painful bone metastases. In order to expand the clinical applications of ZA toward the extraskeletal tumor treatment, it is essential to develop the functionalized nanocarriers capable of carrying high ZA payload and achieving intracellular triggered ZA release. In this end, the ZA-encapsulated hybrid polymeric nanoparticles were fabricated in this work by co-association of the amphiphilic diblock copolymer poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-b-PEG), tocopheryl polyethylene glycol succinate (TPGS) segments and ionic complexes composed of ZA molecules and branched poly(ethylenimine) (PEI) segments. Notably, the ionic pairings of PEI segments with ZA molecules not only assisted encapsulation of ZA into the PLGA-rich core of hybrid nanoparticles but also reduced adhesion of ZA on the surfaces of hydrophobic cores, thus largely increasing ZA loading capacity. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) characterization revealed that the ZA/PEI-loaded nanoparticles had a well-dispersed spherical shape. Moreover, compared to short PEI1.8k (1.8 kDa) segments, the longer PEI10k (10 kDa) segments formed more robust complexes with ZA molecules, thus prominently promoting ZA loading content of hybrid nanoparticles and their colloidal stability. Interestingly, with the suspension pH being reduced from 7.4 to 5.0, the considerable disruption of ZA/PEI ionic complexes owing to the acid-activated protonation of ZA molecules and the developed proton sponge-like effect inside the nanoparticle matrix upon the protonated PEI segments facilitated the rapid release of ZA molecules from drug-loaded hybrid nanoparticles. The results of in vitro cellular uptake and cytotoxicity studies showed that the ZA/PEI-loaded hybrid nanoparticles were internalized by MCF-7 cells upon energy-dependent endocytosis and displayed a superior cytotoxic effect to free ZA. This work demonstrates that the unique ZA/PEI-loaded hybrid polymeric nanoparticles display great promise for anticancer applications.