Biomimetic Hydrogel-Mediated Mechano-Immunometabolic Therapy for Inhibition of ccRCC Recurrence After Surgery.

The unique physical tumor microenvironment (TME) and aberrant immune metabolic status are two obstacles that must be overcome in cancer immunotherapy to improve clinical outcomes. Here, an in situ mechano-immunometabolic therapy involving the injection of a biomimetic hydrogel is presented with sequential release of the anti-fibrotic agent pirfenidone, which softens the stiff extracellular matrix, and small interfering RNA IDO1, which disrupts kynurenine-mediated immunosuppressive metabolic pathways, together with the multi-kinase inhibitor sorafenib, which induces immunogenic cell death. This combination synergistically augmented tumor immunogenicity and induced anti-tumor immunity. In mouse models of clear cell renal cell carcinoma, a single-dose peritumoral injection of a biomimetic hydrogel facilitated the perioperative TME toward a more immunostimulatory landscape, which prevented tumor relapse post-surgery and prolonged mouse survival. Additionally, the systemic anti-tumor surveillance effect induced by local treatment decreased lung metastasis by inhibiting epithelial-mesenchymal transition conversion. The versatile localized mechano-immunometabolic therapy can serve as a universal strategy for conferring efficient tumoricidal immunity in "cold" tumor postoperative interventions.

Oral colon-targeted responsive alginate/hyaluronic acid-based hydrogel propels the application of infliximab in colitis.

Currently, commercialized infliximab (IFX) has rapidly propelled the clinical treatment of IBD, however, its inherent attributes, such as off-target effects and rapid metabolism, severely limit practical applications. Moreover, high doses injection of IFX can result in IBD treatment failure, which may induce other side effects. In this study, an colon microenvironment-responsive hydrogel (AL/HA hydrogel), consisting of acid-resistant sodium alginate and colon-degraded and targeted hyaluronic acid, was constructed by simple Ca2+/Zn2+ cross-linking. The ion-mediated hydrogel exhibited the protective effect of gastrointestinal tract to avoid early drug leakage, while the inflammation environments showed well-controlled drug release and significant biodegradable behaviors. Additionally, oral hydrogel exhibited long-standing enteritis areas compared with normal mice. Therefore, hydrogel-assisted enteritis treatment has great potential in IBD as an oral agent. After that, IFX was packaged in hydrogel to fabricate a facile oral antibody delivery system to treat IBD. IFX-embedded hydrogel showed remarkable therapeutic effect on IBD compared with free IFX. Surprisingly, oral hydrogel below 7 times IFX achieve the same amount of IFX-infused treatment that will further help alleviate the drawbacks of IFX. Our work elaborated on the efficacy of oral AL/HA@IFX in IBD, providing a guarantee for the future of promoted clinical transformation.

Acid-labile anhydride-linked doxorubicin-doxorubicin dimer nanoparticles as drug self-delivery system with minimized premature drug leakage and enhanced anti-tumor efficacy.

Acid-labile anhydride-linked doxorubicin-doxorubicin dimers (D-DOX) were designed as doxorubicin-doxorubicin conjugate-based drug self-delivery systems (DSDSs) with high drug content for tumor intracellular pH-triggered release, by conjugating doxorubicin (DOX) with various anhydrides, such as maleic anhydride (MAH), succinic anhydride (suc), and 2,3-dimethylmaleic anhydride (DMMAH). With the similar diameter of about 200 nm, the D-DOXMAH showed better pH-triggered DOX release and was thus selected for the further investigation. The D-DOX-5 nanoparticles with desirable average hydrodynamic diameter (Dh) of 162 nm and high drug content of 51.20% were obtained via self-assembly by a facile dialysis technique, with the PEGylated dimer (D-DOXMAH-S-PEG) as surfactant. The cumulative DOX release from the proposed D-DOX nanoparticles reached 40.6% within 36 h in the simulated tumor intracellular acidic micro-environment, while the premature drug leakage was only 4.5% in the simulated normal physiological medium. The MTT results indicated the proposed DSDS possessed an enhanced anti-tumor efficacy for the HepG2 cancer cell than the free DOX.

pH/Reduction dual-responsive comet-shaped PEGylated CQD-DOX conjugate prodrug: Synthesis and self-assembly as tumor nanotheranostics.

Carbon quantum dots (CQDs) show promising potential for tumor imaging owing to their unique superior fluorescent properties. However, the small particle size limits their practical application. Here, pH/reduction dual-responsive comet-shaped PEGylated CQD-DOX conjugate prodrug, DOX-Hy-CQD-SS-PEG with DOX content of 28.5%, was designed with the hydrophobic acid-labile DOX conjugated CQDs as comet nucleus and the few hydrophilic bioreducible detachable PEG brushes as comet tails. The comet-shaped DOX-Hy-CQD-SS-PEG prodrug could self-assemble into unique micelles with mean diameter of 127 nm. The DOX-Hy-CQD-SS-PEG micelles possessed excellent pH/reduction dual-responsive drug release with low drug leakage of 9% in 150 h. Furthermore, the fluorescent CQDs was recovered after DOX release and de-PEGylation, demonstrating their potential application for real-time response of therapy.

Tumor-specific fluorescent Cdots-based nanotheranostics by acid-labile conjugation of doxorubicin onto reduction-cleavable Cdots-based nanoclusters.

Carbon quantum dots (Cdots) have attracted more and more interests in bioimaging and tumor theranostics. However, their practical application has been limited due to the small particle size and non-tumor-specific fluorescence. Here, reduction-cleavable disulfide-linked Cdots-based nanoclusters were fabricated to conjugate doxorubicin (DOX) via an acid-labile hydrazone bond. Owing to the pH and reduction dual-stimuli responsiveness, the proposed Cdots-based nanotheranostics possessed unique tumor-specific fluorescent property and tumor-specific controlled drug release performance, indicating their promising potential for the in-situ real-time fluorescent monitoring of therapeutic response in future tumor therapy.

pH-Activated surface charge-reversal double-crosslinked hyaluronic acid nanogels with feather keratin as multifunctional crosslinker for tumor-targeting DOX delivery.

Feather keratin (FK) was used as a multifunctional crosslinker for the fabrication of both pH responsive ionically and reduction responsive covalently crosslinked hyaluronic acid (HA) nanogels, as pH-activated surface charge-reversal double-crosslinked protein/polysaccharide complex nanocarriers for the tumor-targeting DOX delivery. The effect of the preparation condition on the diameter and the drug-loading capacity of the resultant drug delivery systems (DDSs) were investigated in detail. The in vitro controlled release profiles indicated the pH/reduction dual-responsive sustained release of DOX from the proposed double-crosslinked DOX@C-FK/HA nanogels. The in vitro experiments demonstrated that the DOX@C-FK/HA nanogels could be internalized into the HCT 116 cells via a CD44-receptor-mediated endocytosis pathway, exhibiting an enhanced anti-tumor efficacy than the free DOX.

Design, postpolymerization conjugation and self-assembly of a di-block copolymer-based prodrug for tumor intracellular acid-triggered DOX release.

A novel di-block copolymer-based prodrug was designed by atom transfer radical polymerization (ATRP) of glycidyl methacrylate (GMA) with a polyethylene glycol-based initiator (PEG-Br), postpolymerization aldehyde-modification, and doxorubicin (DOX) conjugation via an acid-labile imine bond. The polyprodrug could self-assemble into core-shell structured nanoparticles with the PEG block as the hydrophilic shell and the DOX-containing block as the hydrophobic core. The longer hydrophobic block resulted in a higher drug content but a bigger particle size, although all the four polyprodrug nanoparticles showed excellent fast pH-triggered DOX release owing to the auto-acceleration mechanism because of the transformation from the hydrophobic to semi-hydrophobic block during DOX release, with a cumulative release of >79% in the simulated tumor microenvironment within 12 h and a premature drug leakage of <14%. So the PEG-P(GMA-CBA)51-DOX polyprodrug with a middle hydrophobic block length was optimized as a promising drug delivery system (DDS), with a hydrodynamic diameter around 250 nm and a high DOX content of 30.35%. The in vitro cellular experiments indicated that the PEG-P(GMA-CBA)51-DOX polyprodrug nanoparticles could efficiently deliver DOX into the cell nuclei and show an enhanced anti-tumor efficacy on the HepG2 cells compared to the free DOX.

Polymeric prodrug microspheres with tumor intracellular microenvironment bioreducible degradation, pH-triggered "off-on" fluorescence and drug release for precise imaging-guided diagnosis and chemotherapy.

Theranostic nanoplatforms have been recognized for imaging-guided diagnosis and chemotherapy of cancer by integrating imaging function into the drug delivery systems (DDSs). Here, a facile approach was developed for the fabrication of polymeric prodrug microspheres by introducing pH sensitive "off-on" fluorochrome Rhodamine 6G into bioreducible cleavable bisulfide crosslinked PEGylated poly(glycidyl methacrylate) (PEG-PGMA) microspheres, followed with chemical conjugation of doxorubicin (DOX) via an acid-labile hydrazone linkage. High drug content of 25.4% was achieved for the final PEG-PGMA-Hy-DOX prodrug microspheres with average hydrodynamic diameter of 332 nm. The in vitro controlled release showed leakage-free in physiological medium but a sustained drug release up to 58% within 56 h in tumor intracellular microenvironment. The cellular experiments showed that the PEG-PGMA-Hy-DOX prodrug microspheres could be effectively internalized into HepG2 cells with enhanced anti-tumor efficacy than the free DOX. Furthermore, they showed fluorescence only in tumor intracellular microenvironment, indicating their promising potential for precise imaging-guided diagnosis and chemotherapy.

Versatile Polymeric Microspheres with Tumor Microenvironment Bioreducible Degradation, pH-Activated Surface Charge Reversal, pH-Triggered "off-on" Fluorescence and Drug Release as Theranostic Nanoplatforms.

Facile approach has been developed for the versatile polymeric microspheres with tumor microenvironment bioreducible degradation, pH-activated surface charge reversal, pH-triggered "off-on" fluorescence, and drug release via emulsion copolymerization of glycidyl methacrylate (GMA), poly(ethylene glycol) methyl ether methacrylate (PEGMA), and N-rhodamine 6G-ethyl-acrylamide (Rh6GEAm) with N, N-bis(acyloyl)cystamine) (BACy) as disulfide cross-linker and functionalization. The final PGMA-DMMA microspheres showed excellent cytocompatibility, pH-triggered surface charge reversal at pH 5-6, strong fluorescence only in acidic media, and bioreducible degradation with high reductant level, indicating their promising application as theranostic nanoplatforms for precise imaging-guided diagnosis and chemotherapy. The DOX-loaded PGMA-DMMA microspheres with a drug-loading capacity of 18% and particle size of about 150 nm possessed unique pH/reduction dual-responsive controlled release, with a cumulative DOX release of 60.5% within 54 h at the simulated tumor microenvironment but a premature leakage of <8.0% under the simulated physiological condition. Enhanced inhibition efficacy against HepG2 cells was achieved compared to free DOX.

Facile Synthesis of Fluorescent Hyper-Cross-Linked ß-Cyclodextrin-Carbon Quantum Dot Hybrid Nanosponges for Tumor Theranostic Application with Enhanced Antitumor Efficacy.

Fluorescent hyper-cross-linked ß-cyclodextrin-carbon quantum dot (ß-CD-CQD) hybrid nanosponges of about 200 nm with excellent biocompatibility and strong bright blue fluorescence excited at 365 nm with a high photoluminescence quantum yield (PLQY) of 38.0% were synthesized for tumor theranostic application by facile condensation polymerization of carbon quantum dots (CQDs) with ß-cyclodextrin (ß-CD) at a feeding ratio of 1:5. The DOX@ß-CD-CQD theranostic nanomedicine, around 300 nm with DOX-loading capacity of 39.5% by loading doxorubicin (DOX) via host-guest complexation, showed a pH responsive controlled release and released DOX in the simulated tumor microenvironment in a sustained release mode, owing to the formation constant in the supramolecular complexation of DOX with the ß-CD units in the ß-CD-CQD nanosponges. The proposed DOX@ß-CD-CQD theranostic nanomedicine could be internalized into HepG2 cells, and the released DOX was accumulated into the cell nuclei, demonstrating an antitumor efficacy more enhanced than that of the free drug.

Alginate-based cancer-associated, stimuli-driven and turn-on theranostic prodrug nanogel for cancer detection and treatment.

Alginate-based cancer-associated, stimuli-driven and turn-on theranostic prodrug nanogels were designed for the tumor diagnosis and chemotherapy, by crosslinking the folate-terminated poly(ethylene glycol) (FA-PEG-NH2) and rhodamine B (RhB)-terminated poly(ethylene glycol) (RhB-PEG-NH2) modified oxidized alginate (OAL-g-PEG-FA/RhB) with cystamine (Cys), followed covalent conjugation of doxorubicin (DOX) via acid-labile Schiff base bond. Owing to the surface folic acid (FA) groups, disulfide crosslinking structure and Schiff base conjugation for DOX, the folate receptor (FR)-mediated targeting and pH/reduction dual responsive intracellular triggered release of DOX was achieved. The cytotoxicity and cellular uptake results clearly illustrated that most DOX was released and accumulated in the cell nuclei and killed the cancer cells efficaciously, due to the desirable targeting intracellular triggered release. Furthermore, the theranostic nanogels could be used for the real-time and noninvasive location tracking to cancer cells, owing to the pH-modulated fluorescence property of the pendant RhB groups.

Design of pH/reduction dual-responsive nanoparticles as drug delivery system for DOX: Modulating controlled release behavior with bimodal drug-loading.

pH/Reduction dual-responsive P(FPA-co-PEGMA-co-MAA) (PFPM) nanoparticles were designed for tumor-specific intracellular triggered release of anticancer drug DOX by emulsion copolymerization of 4-formylphenyl acrylate (FPA), methacrylic acid (MAA), and poly(ethylene glycol) methyl ether methacrylate (PEGMA), with N,N-bis(acryloyl)cystamine (BACy) as crosslinker. Then three drug delivery systems (DDSs) with average hydrodynamic diameter around 200nm and drug-loading capacity (DLC) of >35% were obtained via the noncovalent interaction of DOX with the carboxyl and aldehyde groups in MAA and FPA units, covalently conjugating DOX onto the FPA units via acid-labile imine bond, or both the two modes. The in vitro release profiles showed that all the three DDSs exhibited good tumor intracellular triggered release characteristic whitout burst release. And the bimodal drug-loaded one (DOX/PFPMC+N), which had the highest DLC of >54%, possessed the middle drug release rate, faster than the one via covalent conjugation (DOX/PFPMC) but slower than the one via noncovalent interaction (DOX/PFPMN). The results demonstrated that the controlled release behavior of such functional nanoparticles could be tailored with drug-loading modes.

Multi-functionalized hyaluronic acid nanogels crosslinked with carbon dots as dual receptor-mediated targeting tumor theranostics.

Hyaluronic acid (HA)-based theranostic nanogels were designed for the tumor diagnosis and chemotherapy, by crosslinking the folate-terminated poly(ethylene glycol) modified hyaluronic acid (FA-PEG-HA) with carbon dots (CDs) for the first time. Due to the extraordinary fluorescence property of the integrated CDs, the theranostic nanogels could be used for the real-time and noninvasive location tracking to cancer cells. HA could load Doxorubicin (DOX) via electrostatic interaction with a drug-loading capacity (DLC) of 32.5%. The nanogels possessed an ideal release of DOX in the weak acid environment, while it was restrained in the neutral media, demonstrating the pH-responsive controlled release behavior. The cytotoxicity and cellular uptake results clearly illustrated that most DOX was released and accumulated in the cell nuclei and killed the cancer cells efficaciously, due to their dual receptor-mediated targeting characteristics.

PEGylated Oxidized Alginate-DOX Prodrug Conjugate Nanoparticles Cross-Linked with Fluorescent Carbon Dots for Tumor Theranostics.

Theranostic nanomedicine has recently emerged as an appealing approach for tumor chemotherapy. Here, for the first time, fluorescent carbon dots (Cdots) were used as cross-linker for tumor theranostic nanoparticles. Novel theranostic nanoparticles of approximately 27 nm with a doxorubicin (DOX) content of 0.2532 mg/mg (mPEG-OAL-DOX/Cdots) were designed by conjugating DOX onto mPEG-OAL/Cdots nanoparticles that were prepared by cross-linking the PEGylated oxidized alginate (mPEG-OAL) with Cdots. Due to the acid-labile Schiff base conjugating linkage, the theranostic prodrug nanoparticles showed low levels of DOX release in the simulated physiological media, which indicated premature drug leakage could be reduced during body circulation. Interestingly, the in vitro DOX release was triggered in the simulated tumor microenvironment without burst release. MTT assay and CLSM analysis showed that the mPEG-OAL/Cdots nanoparticles were noncytotoxic, but that the mPEG-OAL-DOX/Cdots theranostic nanoparticles exhibited high degrees of inhibition of cancer cells due to their nucleus-targeting DOX delivery. In addition, their cellular fluorescence characteristic demonstrated a potential application for imaging-guided drug delivery in tumor treatment.