Poly(ethylene glycol) shell-sheddable TAT-modified core cross-linked nano-micelles: TAT-enhanced cellular uptake and lysosomal pH-triggered doxorubicin release

Construction of a smart dual-responsive targeted drug nanocarrier for imaging and treatment of breast cancer cells

Breast cancer has become one of the most common cancers worldwide, but the effectiveness of the conventional drug chemotherapy is still restricted. Therefore, precision imaging and targeted therapy against breast cancer cells have become a hot research topic. In this study, a dual-responsive nanocarrier system based on multi-functionalized gold nanoparticles (GNP) was developed for simultaneous diagnosis and treatment of breast cancer cells. The nanoparticles were modified with an aptamer which specifically recognizes MUC-1 protein on the surface of the breast cancer cell MCF-7, achieving precise cellular targeting. Upon entry into the cell, the decrease of pH in the intracellular environment causes the detachment of the i-motif sequence from GNP. Cy5 labeled at the end of i-motif, which is previously quenched by GNP thus restores its fluorescence, achieving the imaging of the cancer cells. Additionally, chemotherapeutic drug gemcitabine (GEM) is covalently attached to GNP through a rationally designed oligopeptide linker CGFLG. Cathepsin B, which is overexpressed in MCF-7 cells, can precisely cleave the CGFLG linker and release GEM to the cells, thereby achieving the targeted drug delivery and treatment. When 4 nM nanocarrier was applied, the inhibition rate of MCF-7 cells was approximately 70 %. This dual-responsive nanocarrier system integrates the targeting, imaging and therapeutic functions in a simple GNP platform. The high targeting efficiency of the nanocarrier reduces the non-specific binding and toxic effects on normal cells, while enhances the toxicity toward cancer cells. Therefore, it may have great prospects in medical applications.

Acid-Activated TAT Peptide-Modified Biomimetic Boron Nitride Nanoparticles for Enhanced Targeted Codelivery of Doxorubicin and Indocyanine Green: A Synergistic Cancer Photothermal and Chemotherapeutic Approach

The evolution of nano-drug delivery systems addresses the limitations of conventional cancer treatments with stimulus-responsive nanomaterial-based delivery systems presenting temporal and spatial advantages. Among various nanomaterials, boron nitride nanoparticles (BNNs) demonstrate significant potential in drug delivery and cancer treatment, providing a high drug loading capacity, multifunctionality, and low toxicity. However, the challenge lies in augmenting nanomaterial accumulation exclusively within tumors while preserving healthy tissues. To address this, we introduce a novel approach involving cancer cell membrane-functionalized BNNs (CM-BIDdT) for the codelivery of doxorubicin (Dox) and indocyanine green to treat homologous tumor. The cancer cell membrane biomimetic CM-BIDdT nanoparticles possess highly efficient homologous targeting capabilities toward tumor cells. The surface modification with acylated TAT peptides (dTAT) further enhances the nanoparticle intracellular accumulation. Consequently, CM-BIDdT nanoparticles, responsive to the acidic tumor microenvironment, hydrolyze amide bonds, activate the transmembrane penetrating function, and achieve precise targeting with substantial accumulation at the tumor site. Additionally, the photothermal effect of CM-BIDdT under laser irradiation not only kills cells through thermal ablation but also destroys the membrane on the surface of the nanoparticles, facilitating Dox release. Therefore, the fabricated CM-BIDdT nanoparticles orchestrate chemo-photothermal combination therapy and effectively inhibit tumor growth with minimal adverse effects, holding promise as a new modality for synergistic cancer treatment.

Superparamagnetic Artificial Cells PLGA-Fe3O4 Micro/Nanocapsules for Cancer Targeted Delivery

Artificial cells have been extensively used in many fields, such as nanomedicine, biotherapy, blood substitutes, drug delivery, enzyme/gene therapy, cancer therapy, and the COVID-19 vaccine. The unique properties of superparamagnetic Fe3O4 nanoparticles have contributed to increased interest in using superparamagnetic artificial cells (PLGA-Fe3O4 micro/nanocapsules) for targeted therapy. In this review, the preparation methods of Fe3O4 NPs and superparamagnetic artificial cell PLGA-drug-Fe3O4 micro/nanocapsules are discussed. This review also focuses on the recent progress of superparamagnetic PLGA-drug-Fe3O4 micro/nanocapsules as targeted therapeutics. We shall concentrate on the use of superparamagnetic artificial cells in the form of PLGA-drug-Fe3O4 nanocapsules for magnetic hyperthermia/photothermal therapy and cancer therapies, including lung breast cancer and glioblastoma.

Application of tumor pH/hypoxia-responsive nanoparticles for combined photodynamic therapy and hypoxia-activated chemotherapy

Introduction: Cancer selectivity, including targeted internalization and accelerated drug release in tumor cells, remains a major challenge for designing novel stimuli-responsive nanocarriers to promote therapeutic efficacy. The hypoxic microenvironment created by photodynamic therapy (PDT) is believed to play a critical role in chemoresistance. Methods: We construct dual-responsive carriers (^DANP_CT) that encapsulate the photosensitizer chlorin e6 (Ce6) and hypoxia-activated prodrug tirapazamine (TPZ) to enable efficient PDT and PDT-boosted hypoxia-activated chemotherapy. Results and discussion: Due to TAT masking, ^DANP_CT prolonged payload circulation in the bloodstream, and selective tumor cell uptake occurred via acidity-triggered TAT presentation. PDT was performed with a spatially controlled 660-nm laser to enable precise cell killing and exacerbate hypoxia. Hypoxia-responsive conversion of the hydrophobic NI moiety led to the disassembly of ^DANP_CT, facilitating TPZ release. TPZ was reduced to cytotoxic radicals under hypoxic conditions, contributing to the chemotherapeutic cascade. This work offers a sophisticated strategy for programmed chemo-PDT.

Well-Defined Shell-Sheddable Core-Crosslinked Micelles with pH and Oxidation Dual-Response for On-Demand Drug Delivery

Micellar-nanocarrier-based drug delivery systems possessing characteristics such as an excellent circulation stability, inhibited premature release and on-demand site-specific release are urgently needed for enhanced therapeutic efficacy. Therefore, a novel kind of shell-sheddable core-crosslinked polymeric micelles with pH and oxidation dual-triggered on-demand drug release behavior was facilely constructed. The multifunctional micelles were self-assembled from a carefully designed amphiphilic triblock PEGylated polyurethane (PEG-acetal-PUBr-acetal-PEG) employing an acid-labile acetal linker at the hydrophilic-hydrophobic interface and pendant reactive bromo-containing polyurethane (PU) as the hydrophobic block, followed by a post-crosslinking via oxidation-cleavable diselenide linkages. These well-defined micelles exhibited an enhanced structural stability against dilution, achieved through the incorporation of diselenide crosslinkers. As expected, they were found to possess dual pH- and oxidation-responsive dissociation behaviors when exposure to acid pH (~5.0) and 50 mM H₂O₂ conditions, as evidenced using dynamic light-scattering (DLS) and atomic force microscopy (AFM) analyses. An in vitro drug release investigation showed that the drug indomethacin (IND) could be efficiently encapsulated in the micelles, which demonstrated an inhibited premature release compared to the non-crosslinked ones. It is noteworthy that the resulting micelles could efficiently release entrapped drugs at a fast rate in response to either pH or oxidation stimuli. Moreover, the release could be significantly accelerated in the presence of both acid pH and oxidation conditions, relative to a single stimulus, owing to the synergetic degradation of micelles through pH-induced dePEGylation and oxidation-triggered decrosslinking processes. The proposed shell-sheddable core-crosslinked micelles with a pH and oxidation dual-response could be potential candidates as drug carriers for on-demand drug delivery.

Nano-encapsulation of halofuginone hydrobromide enhances anticoccidial activity against Eimeria tenella in chickens

Coccidiosis is a worldwide epidemic intestinal disease with high incidence, which causes huge economic losses. Halofuginone hydrobromide (HF) is widely applied as an effective anticoccidial drug in the poultry industry. However, its therapeutic efficacy is severely restrained due to toxic effects, poor aqueous solubility and low permeability. Nanotechnology can improve the biological effect of drugs, and thus, reduce administered doses and toxic effects. The objective of this study was to investigate the therapeutic and preventive potential of novel HF-loaded D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) polymer micelles (HTPM) for preventing coccidiosis in chickens. The HTPM were approximately spherical with a hydrodynamic diameter of 12.65 ± 0.089 nm, a zeta potential of 8.03 ± 0.242 mV, a drug loading of 14.04 ± 0.12%, and an encapsulation efficiency of 71.1 ± 4.15%. HF was encapsulated in the polymer micelles through interactions with TPGS, as characterized by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Cellular take up assays showed that TPGS polymer micelles could enhance drug internalization to alleviate intestinal apoptosis induced by coccidiosis and promote the necrosis of second-generation merozoites of E. tenella. Notably, clinical trials proved that 1.5 mg L^-1 HTPM had a stronger anticoccidial effect on E. tenella than that of 3 mg kg^-1 HF premix. Amplicon sequencing identified that HTPM could alleviate coccidiosis by restoring the structure of the gut microbiome. These findings indicated that the anticoccidial efficacy of HF was significantly enhanced after being encapsulated in polymer micelles, and further demonstrated the potential protective application of nano-encapsulating anticoccidial drugs as a promising approach to control coccidiosis in poultry. In summary, HTPM hold huge potential as an effective therapeutic agent for coccidiosis.

Chitosan-based DDSs for pH/hypoxia dual-triggered DOX delivery: Facile morphology modulation for higher in vitro cytotoxicity

The morphology of the drug delivery systems (DDSs) has been recognized to play an important role in their phagocytosis, cellular interaction and distribution. However, it is a technical challenge to simply prepare the non-spherical nanoscaled DDSs. Here, a facile strategy was developed to fabricate the pH/hypoxia dual-responsive nanowires by adding the maleic acid (MAH) and PEG modified chitosan (PEG-SS-CS-MAH) into aqueous solution of DOX. Compared with the PEG-SS-CS-MAH/DOX nanoparticles (NPs) by adding DOX into the PEG-SS-CS-MAH solution, the PEG-SS-CS-MAH/DOX nanowires (NWs) possessed a higher drug loading capacity of 58% and better pH/hypoxia dual-triggered DOX release performance with higher drug release in the simulated tumor intracellular microenvironment but a much lower premature drug leakage in the simulated normal physiological medium. As a result, higher in vitro anti-tumor efficacy was achieved with the PEG-SS-CS-MAH/DOX NWs, demonstrating their promising potential for tumor chemotherapy.

Stimuli-Responsive Poly(aspartamide) Derivatives and Their Applications as Drug Carriers

Poly(aspartamide) derivatives, one kind of amino acid-based polymers with excellent biocompatibility and biodegradability, meet the key requirements for application in various areas of biomedicine. Poly(aspartamide) derivatives with stimuli-responsiveness can usually respond to external stimuli to change their chemical or physical properties. Using external stimuli such as temperature and pH as switches, these smart poly(aspartamide) derivatives can be used for convenient drug loading and controlled release. Here, we review the synthesis strategies for preparing these stimuli-responsive poly(aspartamide) derivatives and the latest developments in their applications as drug carriers.

Utilizing Stimuli Responsive Linkages to Engineer and Enhance Polymer Nanoparticle-Based Drug Delivery Platforms

The devastating nature of cancer continues to be one of the leading causes of death in the world. Chemotherapy is among the most common forms of cancer treatment but comes with a host of adverse effects caused by the therapeutic agents damaging healthy tissue and organs. To limit these side effects, scientists have been designing stimuli responsive drug delivery vessels for targeted release. This Review focuses on the incorporation of stimuli responsive linkages in targeted drug delivery systems to enhance therapeutic efficiency. These platforms are primarily employed to control the distribution of anticancer agents in the body to reduce the adverse side effects caused by their toxicities. We will outline how drug delivery vessels are constructed so that exposure to select environmental and external stimuli releases the enclosed drug only at the target site. Stimuli responsive components are integrated within drug delivery vessels in the form of cross-linkers, polymers, and surface modifications. The changes, these moieties undergo upon stimuli exposure, cascade into larger scale alterations to the platforms, resulting in complete disassembly, reversible morphological variations, and enhanced cellular uptake. The ability for these modes of delivery to be initiated exclusively under stimuli exposure allows for release of toxic therapeutic agents to be confined only to the affected area.

Hyaluronic acid reduction-sensitive polymeric micelles achieving co-delivery of tumor-targeting paclitaxel/apatinib effectively reverse cancer multidrug resistance

Multidrug resistance (MDR) of cancer cells is a significant challenge in chemotherapy, highlighting the urgent medical need for simple and reproducible strategies to reverse this process. Here, we report the development of an active tumor-targeting and redox-responsive nanoplatform (PA-ss-NP) using hyaluronic acid-g-cystamine dihydrochloride-poly-ε-(benzyloxycarbonyl)-L-lysine (HA-ss-PLLZ) to co-deliver paclitaxel (PTX) and apatinib (APA) for effective reversal of MDR. This smart nanoplatform specifically bound to CD44 receptors, leading to selective accumulation at the tumor site and uptake by MCF-7/ADR cells. Under high concentrations of cellular glutathione (GSH), the nanocarrier was degraded rapidly with complete release of its encapsulated drugs. Released APA effectively inhibited the function of the P-glycoprotein (P-gp) drug pump and improved the sensitivity of MDR cells to chemotherapeutic agents, leading to the recovery of PTX chemosensitivity in MDR cells. As expected, this newly developed intelligent drug delivery system could effectively control MDR, both in vitro and in vivo.

Nuclear-targeted nanocarriers based on pH-sensitive amphiphiles for enhanced GNA002 delivery and chemotherapy

GNA002, a novel EZH2 inhibitor, exhibits significant anticancer efficiency in solid malignant tumor therapy; however, its poor water solubility and low enrichment at tumor sites limit its clinical application and translation. In this study, an original pH-sensitive nanocarrier (cyclo (RGDyCSH) (cRGD)-poly (ethylene glycol) (PEG)-hydrazine (Hyd)-hexa-arginine (R6)-stearic acid (SA)) was designed to precisely deliver GNA002 into the nuclei of cancer cells. The PEG-modified hydrophilic shell of the spherical GNA002-loaded nanoparticles with a mean size of 143.13 ± 0.20 nm effectively facilitated the passive target of tumor tissues and prolonged the blood circulation time. Meanwhile, cRGD was used as the active targeting ligand, which promoted the accumulation of the nanoparticles in cancer cells via ανβ3-receptor-mediated endocytosis. Furthermore, the acidic environment of lysosomes triggered the rupture of the pH-sensitive hydrazine bond and the rapid formation of penetrating peptide R6-shelled secondary nanoparticles, thus enabling the lysosomal escape of the nanoparticles and the ultimate R6-mediated nuclear-targeted delivery of GNA002. Consequently, the nuclear-enriched GNA002 effectively enhanced the cytotoxicity against cancer cells both in vitro and in vivo, thus providing an original and promising drug delivery system for the targeted delivery of GNA002.