Nanoaggregates of Disulfide-Decorated TrxR Inhibitor Promote Cellular Uptake, Selective Targeting, and Antitumor Efficacy.

Three self-assembled nanoaggregates (CPUL1-LA NAs, CPUL1-DA NAs, and CPUL1-AA NAs) were constructed through lipoic acid (LA), dithiodipropionic acid (DA), and adipic acid (AA) decorated TrxR inhibitor (CPUL1), respectively. Measurements of DLS, TEM, UV-vis, fluorescence, 1H NMR, ITC, and MTT assays verified disulfide-containing CPUL1-LA NAs and CPUL1-DA NAs spontaneously assembled carrier-free nanoparticles in aqueous solution, which possessed high drug contents, excellent stability, improved cytotoxicity against HUH7 hepatoma cells, and potential biosafety because of low cytotoxicity against L02 normal cells. In contrast, disulfide-free CPUL1-AA NAs happened to aggregate and precipitate after 48 h, which showed distinct instability in aqueous solution. Thus, disulfide units seemed to be crucial for constructing controllable and stable nanoaggregates. While measuring the reduction of nanoaggregates by TrxR/NADPH and GSH/GR/NADPH, cyclic disulfide of LA and linear disulfide of DA were verified to endow the nanoaggregates with targeting ability to respond specifically to TrxR over GSH. Furthermore, by tests of flow cytometry, fluorescence images, and CLSM, both CPUL1-LA NAs and CPUL1-DA NAs displayed a faster cellular uptake characteristic to be internalized by cancer cells and could generate more abundant ROS to induce cell apoptosis than that of free CPUL1, resulting in significantly improved antitumor efficacy against HUH7 cells in vitro.

Robust Construction of Supersmall Zwitterionic Micelles Based on Hyperbranched Polycarbonates Mediates High Tumor Accumulation.

Despite the numerous advantages of nanomedicines, their therapeutic efficacy is hampered by biological barriers, including fast in vivo clearance, poor tumor accumulation, inefficient penetration, and cellular uptake. Herein, cross-linked supersmall micelles based on zwitterionic hyperbranched polycarbonates can overcome these challenges for efficiently targeted drug delivery. Biodegradable acryloyl/zwitterion-functionalized hyperbranched polycarbonates are synthesized by a one-pot sequential reaction of Michael-type addition and ring-opening polymerization, followed by controlled modification with carboxybetaine thiol. Cross-linked supersmall zwitterionic micelles (X-CBMs) are readily prepared by straightforward self-assembly and UV cross-linking. X-CBMs exhibit prolonged blood circulation because of their cross-linked structure and zwitterion decoration, which resist protein corona formation and facilitate escaping RES recognition. Combined with the advantage of supersmall size (7.0 nm), X-CBMs mediate high tumor accumulation and deep penetration, which significantly enhance the targeted antitumor outcome against the 4T1 tumor model by administration of the paclitaxel (PTX) formulation (X-CBM@PTX).

Super-small zwitterionic micelles enable the improvement of blood-brain barrier crossing for efficient orthotopic glioblastoma combinational therapy.

Glioblastoma multiforme (GBM) remains incurable in clinical, nanotechnology-based drug delivery strategies show promising perspective in alleviating GBM, while limited blood-brain-barrier (BBB) permeation, short blood half-live accompanied by the poor tumor accumulation and penetration, significantly restrict the therapeutic outcomes. Herein, a versatile super-small zwitterionic nano-system (MCB(S)) based on carboxybetaine (CB) zwitterion functionalized hyperbranched polycarbonate (HPCB) is developed to overcome the brain delivery challenges. After grafting with amino-functionalized IR780 (free IR780), the ultimate paclitaxel (PTX)-encapsulated micelles (MCB(S)-IR@PTX) are precisely activated by near-infrared (NIR) for accelerated drug release and effective combinational GBM therapy. Importantly, MCB(S)-IR@PTX with the crosslinked structure and CB zwitterion prolongs blood-circulation, and CB-zwitterion further facilitates BBB-traversing through betaine/γ-aminobutyric acid (GABA) transporter-1 (BGT-1) pathway. Combined with the benefit of super small-size, MCB(S)-IR@PTX highly accumulates at tumor sites and penetrates deeply, thus efficiently inhibiting tumor growth and strikingly improving survival time in U87MG orthotopic GBM-bearing mouse model. The ingenious nanoplatform furnishes a versatile strategy for delivering therapeutics into the brain and realizing efficient brain cancer therapy.

Crosslinked zwitterionic microcapsules to overcome gastrointestinal barriers for oral insulin delivery.

Oral insulin delivery has been extensively considered to achieve great patient compliance and convenience as well as favourable glucose homeostasis. However, its application is highly limited by the low insulin bioavailability owing to gastrointestinal barriers. Herein, we developed crosslinked zwitterionic microcapsules (CB-MCs@INS) based on a carboxyl betaine (CB)-modified poly(acryloyl carbonate-co-caprolactone) copolymer via the combination of microfluidics and UV-crosslinking to improve oral insulin delivery. CB-MC@INS microcapsules with high drug loading capacity (>40%) protected insulin from acid degradation in the harsh gastric environment. Through the introduction of CB-moieties, CB-MCs@INS possessed superior affinity for epithelial cells and improved insulin transport as compared to non-CB modified MCs@INS (5.15-fold), which was mainly attributed to the CB-mediated cell surface transporter via the PAT1 pathway. Moreover, the oral administration of CB-MCs@INS exhibited an excellent hypoglycaemic effect and maintained normoglycemia for up to 8 h in diabetic mice, demonstrating the great potential of crosslinked zwitterionic microcapsules as an oral insulin delivery platform for diabetes therapy.

Multifunctional Nanoaggregates Composed of Active CPUL1 and a Triphenylphosphine Derivative for Mitochondria-Targeted Drug Delivery and Cell Imaging.

We report that active substance (CPUL1) and triphenylphosphine (TPP) derivative could self-assemble into multifunctional nanoaggregates (CPUL1-TPP NAs) through electrostatic and π-π stacking interactions. CPUL1 was wrapped tightly inside the nanoparticles as well as CPUL1 and TPP derivative self-assembled into stable and compact nanoparticles in water. The positive surface charge of CPUL1-TPP NAs made them much easier to be endocytosed to enter cytoplasm, accumulate in the mitochondria and induce cell apoptosis based on their mitochondria targeting ability, fluorescence property and fast cell uptake characteristic, which showed better antitumor efficacy on HUH7 hepatoma cells in vitro than that of free CPUL1.

Recent advances on next generation of polyzwitterion-based nano-vectors for targeted drug delivery.

Poly (ethylene glycol) (PEG)-based nanomedicines are perplexed by the challenges of oxidation damage, immune responses after repeated injections, and limited excretion from the body. As an alternative to PEG, bioinspired zwitterions bearing an identical number of positive and negative ions, exhibit exceptional hydrophilicity, excellent biomimetic nature and chemical malleability, endowing zwitterionic nano-vectors with biocompatibility, non-fouling feature, extended blood circulation and multifunctionality. In this review, we innovatively classify zwitterionic nano-vectors into linear, hyperbranched, crosslinked, and hybrid nanoparticles according to different chemical architectures in rational design of zwitterionic nano-vectors for enhanced drug delivery with an emphasis on zwitterionic engineering innovations as alternatives of PEG-based nanomedicines. Through combination with other nanostrategies, the intelligent zwitterionic nano-vectors can orchestrate stealth and other biological functionalities together to improve the efficacy in the whole journey of drug delivery.

Cascade-Responsive Hierarchical Nanosystems for Multisite Specific Drug Exposure and Boosted Chemoimmunotherapy.

The precise delivery of multiple drugs to their distinct destinations plays a significant role in safe and efficient combination therapy; however, it is highly challenging to simultaneously realize the targets and overcome the intricate biological hindrances using an all-in-one nanosystem. Herein, a cascade-responsive hierarchical nanosystem containing checkpoint inhibitor anti-PD-L1 antibody (αPD-L1) and paclitaxel (PTX) is developed for spatially programed delivery of multiple drugs and simultaneously overcoming biological pathway barriers. The hierarchical nanoparticles (MPH-NP@A) are composed of pH-sensitive hyaluronic acid-acetal-PTX prodrugs (HA-ace-PTX(SH)) chaperoned by αPD-L1 and metalloproteinase-9 (MMP-9)-responsive outer shells, which could be fast cleaved to release αPD-L1 in the tumor microenvironment (TME). The released αPD-L1 sequentially synergizes with PTX released in the cytoplasm for boosted chemoimmunotherapy due to direct killing of PTX and intensified immune responses through immunogenic cell death (ICD) as well as suppression of immune escape by blocking the PD-1/PD-L1 axis. The in vitro and in vivo studies demonstrate that MPH-NP@A evokes distinct ICD, enhanced cytotoxic T lymphocytes infiltration, as well as significant tumor inhibition, thus providing a promising therapeutic nano-platform for safe and efficient combination therapy.

Multi-functional polymeric micelles for chemotherapy-based combined cancer therapy.

Currently, the therapeutic performance of traditional mono-chemotherapy on cancers remains unsatisfactory because of the tumor heterogeneity and multidrug resistance. In light of intricate tumor structures and distinct tumor microenvironments (TMEs), combinational therapeutic strategies with multiple anticancer drugs from different mechanisms can synergistically optimize the outcomes and concomitantly minimize the adverse effects during the therapy process. Extensive research on polymeric micelles (PMs) for biomedical applications has revealed the growing importance of nanomedicines for cancer therapy in the recent decade. Starting from traditional simple delivery systems, PMs have been extended to multi-faceted therapeutic strategies. Here we review and summarize the most recent advances in combinational therapy based on multifunctional PMs including a combination of multiple anticancer drugs, chemo-gene therapy, chemo-phototherapy and chemo-immunotherapy. The design approaches, action mechanisms and therapeutic applications of these nanodrugs are summarized. In addition, we highlight the opportunities and potential challenges associated with this promising field, which will provide new guidelines for advanced combinational cancer chemotherapy.