Multimodal nanoimmunotherapy engages neutrophils to eliminate Staphylococcus aureus infections.

The increasing prevalence of antimicrobial resistance in Staphylococcus aureus necessitates alternative therapeutic approaches. Neutrophils play a crucial role in the fight against S. aureus but suffer from deficiencies in function leading to increased infection. Here we report a nanoparticle-mediated immunotherapy aimed at potentiating neutrophils to eliminate S. aureus. The nanoparticles consist of naftifine, haemoglobin (Hb) and a red blood cell membrane coating. Naftifine disrupts staphyloxanthin biosynthesis, Hb reduces bacterial hydrogen sulfide levels and the red blood cell membrane modifies bacterial lipid composition. Collectively, the nanoparticles can sensitize S. aureus to host oxidant killing. Furthermore, in the infectious microenvironment, Hb triggers lipid peroxidation in S. aureus, promoting neutrophil chemotaxis. Oxygen supplied by Hb can also significantly enhance the bactericidal capability of the recruited neutrophils by restoring neutrophil respiratory burst via hypoxia relief. This multimodal nanoimmunotherapy demonstrates excellent therapeutic efficacy in treating antimicrobial-resistant S. aureus persisters, biofilms and S. aureus-induced infection in mice.

Research progress on the nucleoside/nucleotide-loaded nanomedicines. / æ ¸è‹·ç±»è¯ç‰©çº³ç±³é€’é€ç³»ç»Ÿç ”ç©¶è¿›å±•.

Nucleoside drugs play an essential role in treating major diseases such as tumor and viral infections, and have been widely applied in clinics. However, the effectiveness and application of nucleoside drugs are significantly limited by their intrinsic properties such as low bioavailability, lack of targeting ability, and inability to enter the cells. Nanocarriers can improve the physiological properties of nucleoside drugs by improving drug delivery efficiency and availability, maintaining drug efficacy and system stability, adjusting the binding ability of the carrier and drug molecules, as well as modifying specific molecules to achieve active targeting. Starting from the design strategy of nucleoside drug nanodelivery systems, the design and therapeutic effect of these nanomedicines are described in this review, and the future development directions of nucleoside/nucleotide-loaded nanomedicines are also discussed.

Targeted PERK inhibition with biomimetic nanoclusters confers preventative and interventional benefits to elastase-induced abdominal aortic aneurysms.

Abdominal aortic aneurysm (AAA) is a progressive aortic dilatation, causing ∼80% mortality upon rupture. Currently, there is no approved drug therapy for AAA. Surgical repairs are invasive and risky and thus not recommended to patients with small AAAs which, however, account for ∼90% of the newly diagnosed cases. It is therefore a compelling unmet clinical need to discover effective non-invasive strategies to prevent or slow down AAA progression. We contend that the first AAA drug therapy will only arise through discoveries of both effective drug targets and innovative delivery methods. There is substantial evidence that degenerative smooth muscle cells (SMCs) orchestrate AAA pathogenesis and progression. In this study, we made an exciting finding that PERK, the endoplasmic reticulum (ER) stress Protein Kinase R-like ER Kinase, is a potent driver of SMC degeneration and hence a potential therapeutic target. Indeed, local knockdown of PERK in elastase-challenged aorta significantly attenuated AAA lesions in vivo. In parallel, we also conceived a biomimetic nanocluster (NC) design uniquely tailored to AAA-targeting drug delivery. This NC demonstrated excellent AAA homing via a platelet-derived biomembrane coating; and when loaded with a selective PERK inhibitor (PERKi, GSK2656157), the NC therapy conferred remarkable benefits in both preventing aneurysm development and halting the progression of pre-existing aneurysmal lesions in two distinct rodent models of AAA. In summary, our current study not only establishes a new intervention target for mitigating SMC degeneration and aneurysmal pathogenesis, but also provides a powerful tool to facilitate the development of effective drug therapy of AAA.

Multifunctional nanoparticle potentiates the in situ vaccination effect of radiation therapy and enhances response to immune checkpoint blockade.

Radiation therapy (RT) activates an in situ vaccine effect when combined with immune checkpoint blockade (ICB), yet this effect may be limited because RT does not fully optimize tumor antigen presentation or fully overcome suppressive mechanisms in the tumor-immune microenvironment. To overcome this, we develop a multifunctional nanoparticle composed of polylysine, iron oxide, and CpG (PIC) to increase tumor antigen presentation, increase the ratio of M1:M2 tumor-associated macrophages, and enhance stimulation of a type I interferon response in conjunction with RT. In syngeneic immunologically "cold" murine tumor models, the combination of RT, PIC, and ICB significantly improves tumor response and overall survival resulting in cure of many mice and consistent activation of tumor-specific immune memory. Combining RT with PIC to elicit a robust in situ vaccine effect presents a simple and readily translatable strategy to potentiate adaptive anti-tumor immunity and augment response to ICB or potentially other immunotherapies.

NAD(H)-loaded nanoparticles for efficient sepsis therapy via modulating immune and vascular homeostasis.

Sepsis is a life-threatening organ dysfunction responsible for nearly 270,000 deaths annually in the United States alone. Nicotinamide adenine dinucleotide (NAD+), an immunomodulator, can potentially treat sepsis; however, clinical application of NAD+ is hindered by its inability to be directly taken up by cells. To address this challenge, a family of nanoparticles (NPs) loaded with either NAD+ or the reduced form of NAD+ (NADH), hereafter NAD(H)-loaded NPs, were engineered to enable direct cellular transport and replenishment of NAD(H). The NAD(H)-loaded NPs improved cellular energy supply, suppressed inflammation and prevented inflammation-induced cell pyroptosis and apoptosis. Therefore, the NPs can help maintain immune homoeostasis and vascular function, two key factors in the pathogenesis of sepsis. The NAD(H)-loaded NPs demonstrated excellent therapeutic efficacies in treating endotoxemia and multidrug-resistant pathogen-induced bacteremia. In addition, the NAD(H)-loaded NPs prevented caecal ligation and puncture-induced multiorgan injury and improved outcomes of secondary Pseudomonas aeruginosa infections following caecal ligation and puncture, thus potentially leading to a highly innovative and translational approach to treat sepsis efficiently and safely.

pH-Responsive Polymer Nanoparticles for Efficient Delivery of Cas9 Ribonucleoprotein With or Without Donor DNA.

Clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (Cas9) may offer new therapeutics for genetic diseases through gene disruption via nonhomologous end joining (NHEJ) or gene correction via homology-directed repair (HDR). However, clinical translation of CRISPR technology is limited by the lack of safe and efficient delivery systems. Here, facilely fabricated pH-responsive polymer nanoparticles capable of safely and efficiently delivering Cas9 ribonucleoprotein alone (termed NHEJ-NP, diameter = 29.4 nm), or together with donor DNA (termed HDR-NP, diameter = 33.3 nm) are reported. Moreover, intravenously, intratracheally, and intramuscularly injected NHEJ-NP induces efficient gene editing in mouse liver, lung, and skeletal muscle, respectively. Intramuscularly injected HDR-NP also leads to muscle strength recovery in a Duchenne muscular dystrophy mouse model. NHEJ-NP and HDR-NP possess many desirable properties including high payload loading content, small and uniform sizes, high editing efficiency, good biocompatibility, low immunogenicity, and ease of production, storage, and transport, making them great interest for various genome editing applications with clinical potentials.

Ultrasound-activable piezoelectric membranes for accelerating wound healing.

Ultrasonic energy harvesting technologies have gained much attention for biomedical applications due to their several desirable features including low-energy attenuation and strong penetration capability. In this work, flexible piezoelectric poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE))/barium titanate (BaTiO3, BT) membranes, capable of converting ultrasound energy to electric energy, were fabricated by an electrospinning process and their effects on the wound healing behaviors with/without ultrasonic stimulation were investigated. The piezoelectric membranes showed excellent electric outputs and can be used as a sustainable power source to quickly charge LEDs and capacitors. The penetration capability of ultrasound waves was investigated by implanting the membranes at different depths of porcine tissue. The membrane was able to generate a high voltage of 8.22 V even at a depth of 4.5 cm. Furthermore, ultrasonic stimulation on the piezoelectric membranes facilitated the proliferation and migration of the fibroblasts, and a cell migration rate of 92.6% was obtained after 24 h in the cell migration test. Under ultrasonic vibration, the electric field generated from the membranes accelerated the wound closure rate in an animal wound model. These results demonstrated the effectiveness of the flexible piezoelectric membranes in stimulating cellular behaviors, which may provide a new therapeutic strategy for wound care.

Biomimetic, ROS-detonable nanoclusters - A multimodal nanoplatform for anti-restenotic therapy.

The long-term success of endovascular intervention has long been overshadowed by vessel re-occlusion, also known as restenosis. Mainstream anti-restenotic devices, such as drug-eluting stent (DES) and drug-coated balloon (DCB), were recently shown with suboptimal performances and life-threatening complications, thereby underpinning the urgent need for alternative strategies with enhanced efficacy and safety profile. In our current study, we engineered a multimodal nanocluster formed by self-assembly of unimolecular nanoparticles and surface coated with platelet membrane, specifically tailored for precision drug delivery in endovascular applications. More specifically, it incorporates the combined merits of platelet membrane coating (lesion targetability and biocompatibility), reactive oxygen species (ROS)-detonable "cluster-bomb" chemistry (to trigger the large-to-small size transition at the target site, thereby achieving longer circulation time and higher tissue penetration), and sustained drug release. Using RVX-208 (an emerging anti-restenotic drug under clinical trials) as the model payload, we demonstrated the superior performances of our nanocluster over conventional poly(lactic-co-glycolic acid) (PLGA) nanoparticle. In cultured vascular smooth muscle cell (VSMC), the drug-loaded nanocluster induced effective inhibition of proliferation and protective gene expression (e.g., APOA-I) with a significantly reduced dosage of RVX-208 (1 µM). In a rat model of balloon angioplasty, intravenous injection of Cy5.5-tagged nanocluster led to greater lesion targetability, improved biodistribution, and deeper penetration into injured vessel walls featuring enriched ROS. Moreover, in contrast to either free drug solution or drug-loaded PLGA nanoparticle formulation, a single injection with the drug-loaded nanocluster (10 mg/kg of RVX-208) was sufficient to substantially mitigate restenosis. Additionally, this nanocluster also demonstrated biocompatibility according to in vitro cytotoxicity assay and in vivo histological and tissue qPCR analysis. Overall, our multimodal nanocluster offers improved targetability, tissue penetration, and ROS-responsive release over conventional nanoparticles, therefore making it a highly promising platform for development of next-generation endovascular therapies.

Hydrogen peroxide-responsive platelet membrane-coated nanoparticles for thrombus therapy.

Occlusion of blood vessels caused by thrombi is the major pathogenesis of various catastrophic cardiovascular diseases. Thrombi can be prevented or treated by antithrombotic drugs. However, free antithrombotic drugs often have relatively low therapeutic efficacy due to a number of limitations such as short half-life, unexpected bleeding complications, low thrombus targeting capability, and negligible hydrogen peroxide (H2O2)-scavenging ability. Inspired by the abundance of H2O2 and the active thrombus-targeting property of platelets, a H2O2-responsive platelet membrane-cloaked argatroban-loaded polymeric nanoparticle (PNPArg) was developed for thrombus therapy. Poly(vanillyl alcohol-co-oxalate) (PVAX), a H2O2-degradable polymer, was synthesized to form an argatroban-loaded nanocore, which was further coated with platelet membrane. The PNPArg can effectively target the blood clots due to the thrombus-homing property of the cloaked platelet membrane, and subsequently exert combined H2O2-scavenging effect via the H2O2-degradable nanocarrier polymer and antithrombotic effect via argatroban, the released payload. The PNPArg effectively scavenged H2O2 and protected cells from H2O2-induced cellular injury in RAW 264.7 cells and HUVECs. The PNPArg rapidly targeted the thrombosed vessels and remarkably suppressed thrombus formation, and the levels of H2O2 and inflammatory cytokines in the ferric chloride-induced carotid arterial thrombosis mouse model. Safety assessment indicated good biocompatibility of the PNPArg. Taken together, the biomimetic PNPArg offers multiple functionalities including thrombus-targeting, antioxidation, and H2O2-stimulated antithrombotic action, thereby making it a promising therapeutic nanomedicine for thrombosis diseases.

A Dual-Responsive Antibiotic-Loaded Nanoparticle Specifically Binds Pathogens and Overcomes Antimicrobial-Resistant Infections.

Antimicrobial resistant (AMR) infections are a growing threat to public health and there is a general lack of development in new antibiotics. Here, a dextran-coated stimuli-responsive nanoparticle (NP) that encapsulates the hydrophobic antibiotic, rifampicin, and specifically binds bacteria to overcome AMR infections is reported. The NP shows a strong affinity with a variety of pathogens in vitro and effectively accumulates in the bacterial infected tissues. The NP is activated by either low pH or high reactive oxygen species in the infectious microenvironment, and releases both cationic polymer and rifampicin that display synergistic activity against AMR pathogens. The NP carrier also enables the antibiotic to penetrate both bacterial biofilms and mammalian cells, thus allowing the elimination of biofilm and intracellular infections. The NP formulation demonstrates both safety and efficacy in two animal infection models against either Gram-negative or Gram-positive AMR pathogens.

Biomimetic fibrin-targeted and H2O2-responsive nanocarriers for thrombus therapy.

Thrombosis is a principle cause of various life-threatening cardiovascular diseases. However, current antithrombotic treatments using drugs only offer limited efficacy due to short half-life, low targeting ability to the thrombus site, and unexpected bleeding complications. Taking into account of the biological characteristics of thrombus including upregulation of hydrogen peroxide (H2O2) and abundance of fibrin, we engineered a H2O2-responsive nanocarrier for thrombus-targeting delivery of an antithrombotic agent (i.e., tirofiban). The nanocarrier was composed of a drug-conjugated dextran nanocore and a red blood cell (RBC) membrane shell, and its surface was functionalized with a fibrin-targeting peptide, CREKA. Tirofiban was conjugated to dextran through a H2O2-cleavable phenylboronic ester linkage. The fibrin-targeting RBC membrane-cloaked dextran-tirofiban conjugate nanoparticles (i.e., T-RBC-DTC NPs) can scavenge H2O2 and provide controlled release of tirofiban to achieve site-specific antithrombotic effects. In RAW 264.7 cells and HUVECs, the T-RBC-DTC NPs effectively scavenged H2O2 and protected cells from H2O2-induced cytotoxicity. In the ferric chloride-induced carotid thrombosis mouse model, the T-RBC-DTC NPs efficiently accumulated at the injured carotid artery and exhibited significantly enhanced antithrombotic activity compared to free drug. The T-RBC-DTC NPs also exhibited good biocompatibility according to histology analysis. Overall, our results indicated that this bioengineered nanocarrier offers a promising therapeutic strategy for thrombotic disorders.

Double-Network Nanogel as a Nonviral Vector for DNA Delivery.

A double-network nanogel, composed of a silane-cross-linked polyethylenimine (PEI) network (i.e., PEI-S) and a pH-responsive poly(2-(hexamethyleneimino) ethyl methacrylate) (PC7A) polymer, was developed for efficient DNA transfection. The chemical cross-linking and hydrophobic interactions in the two networks led to improved stability outside the cell and also pH-triggered intracellular release of DNA. The nanogel with an optimal PEI-S and PC7A weight ratio of 1.3:1 exhibited significantly higher transfection efficiency than Lipofectamine 2000 in multiple cell lines. The nanogel also possessed a small size with a hydrodynamic diameter of 55 nm, low cytotoxicity, and superior stability in serum-containing media. Moreover, besides the PEI-based gene delivery system, we have also demonstrated that addition of the PC7A polymer to several types of cationic polymers commonly used for gene delivery also led to significant transfection enhancement of the resulting nanoparticles, suggesting that the PC7A polymer may be a universal additive that can benefit versatile cationic polymer-based gene delivery systems.

Development of an In Situ Cancer Vaccine via Combinational Radiation and Bacterial-Membrane-Coated Nanoparticles.

Neoantigens induced by random mutations and specific to an individual's cancer are the most important tumor antigens recognized by T cells. Among immunologically "cold" tumors, limited recognition of tumor neoantigens results in the absence of a de novo antitumor immune response. These "cold" tumors present a clinical challenge as they are poorly responsive to most immunotherapies, including immune checkpoint inhibitors (ICIs). Radiation therapy (RT) can enhance immune recognition of "cold" tumors, resulting in a more diversified antitumor T-cell response, yet RT alone rarely results in a systemic antitumor immune response. Therefore, a multifunctional bacterial membrane-coated nanoparticle (BNP) composed of an immune activating PC7A/CpG polyplex core coated with bacterial membrane and imide groups to enhance antigen retrieval is developed. This BNP can capture cancer neoantigens following RT, enhance their uptake in dendritic cells (DCs), and facilitate their cross presentation to stimulate an antitumor T-cell response. In mice bearing syngeneic melanoma or neuroblastoma, treatment with BNP+RT results in activation of DCs and effector T cells, marked tumor regression, and tumor-specific antitumor immune memory. This BNP facilitates in situ immune recognition of a radiated tumor, enabling a novel personalized approach to cancer immunotherapy using off-the-shelf therapeutics.

Enhancing the In Vitro and In Vivo Stabilities of Polymeric Nucleic Acid Delivery Nanosystems.

Gene therapy holds great promise for various medical and biomedical applications. Nonviral gene delivery systems formed by cationic polymer and nucleic acids (e.g., polyplexes) have been extensively investigated for targeted gene therapy; however, their in vitro and in vivo stability is affected by both their intrinsic properties such as chemical compositions (e.g., polymer molecular weight and structure, and N/P ratio) and a number of environmental factors (e.g., shear stress during circulation in the bloodstream, interaction with the serum proteins, and physiological ionic strength). In this review, we surveyed the effects of a number of important intrinsic and environmental factors on the stability of polymeric gene delivery systems, and discussed various strategies to enhance the stability of polymeric gene delivery systems, thereby enabling efficient gene delivery into target cells. Future opportunities and challenges of polymeric nucleic acid delivery nanosystems were also briefly discussed.

Zinc phthalocyanine encapsulated in polymer micelles as a potent photosensitizer for the photodynamic therapy of osteosarcoma.

Zinc phthalocyanine (ZnPc) is a highly potent second-generation photosensitizer for cancer photodynamic therapy (PDT) with attractive photo-physical and photo-chemical properties. However, poor solubility and strong trend of crystallization prevent it from loading in most of drug delivery systems and hamper its further application. Herein, to overcome this problem, an amphiphilic block copolymer poly(ethylene glycol)-poly[2-(methylacryloyl)ethylnicotinate] (PEG-PMAN) with aromatic nicotinate is used to load ZnPc for their π-π interactions. The formed PEG-PMAN/ZnPc nanoparticle (PPZ) dramatically increases reactive oxygen species production in osteosarcoma cells after light irradiation, causes mitochondrial injury and promotes cell cycle arrest at G2/M, leading to a 100-fold cytotoxicity improvement comparing with free ZnPc. The excellent therapeutic effectiveness and safety of PPZ are also proved by in vivo experiments operating on osteosarcoma model. The finding above indicates that PPZ has promising clinical applications as a next-generation photosensitizer in PDT of osteosarcoma.

A Tumor-Specific Cascade Amplification Drug Release Nanoparticle for Overcoming Multidrug Resistance in Cancers.

A cascade amplification release nanoparticle (CARN) is constructed by the coencapsulation of ß-lapachone and a reactive-oxygen-species (ROS)-responsive doxorubicin (DOX) prodrug, BDOX, in polymeric nanoparticles. Releasing ß-lapachone first from the CARNs selectively increases the ROS level in cancer cells via NAD(P)H:quinone oxidoreductase-1 (NQO1) catalysis, which induces the cascade amplification release of DOX and overcomes multidrug resistance (MDR) in cancer cells, producing a remarkably improved therapeutic efficacy against MDR tumors with minimal side effects.

Enhancing MRI of liver metastases with a zwitterionized biodegradable dendritic contrast agent.

Metastasis is the main reason for cancer-associated mortality, and accurate diagnostic imaging of metastases is critical for the clinical administration and tailoring personalized treatments for metastatic tumors. However, magnetic resonance imaging of metastases in the liver is impeded by its low sensitivity because the currently used contrast agents accumulate in hepatocytes and Kupffer cells instead of cancer cells. Herein, a 4th generation zwitterionized biodegradable dendritic contrast agent (DCA) with a size of ca. 9 nm and a longitudinal relaxivity of 15.7 mM-1 s-1 in terms of Gd was synthesized and used to enhance the MRI of liver metastasis. The DCA could remarkably enhance the MRI of metastasized tumors in the liver, because it could simultaneously reduce the background signal in the liver by avoiding uptake by hepatocytes and Kupffer cells through the zwitterionization and increase the signal in tumors through the enhanced permeability and retention effect. Moreover, in contrast to non-biodegradable DCA, this DCA showed minimal long-term Gd3+ retention in all organs and tissues because it could be degraded into small fragments. The significant capability of enhancing the MRI of metastases in the liver plus its excellent biodegradability made this DCA a promising CA for metastatic tumor imaging.

A facile synthesis of a theranostic nanoparticle by oxidation of dopamine-DTPA-Gd conjugates.

Photothermal therapies (PPTs) with various light-absorbing materials have shown very promising therapeutic effects against cancers. However, their application was severely limited by the lack of accurate localization of tumors and real-time monitoring of the therapeutic process. Theranostic nanoparticles with both imaging and therapeutic functions are highly desired to develop imaging-mediated PPTs. Herein, we develop a facile one-pot method to synthesize a nanoparticle with functions of an MRI contrast agent and a PTT agent through oxidization of dopamine-DTPA-Gd conjugates and PEG-dopamine conjugates. The oxidized dopamine nanoparticles (ODNP) had a high R1 up to 9.6 mM-1 s-1, 2.2 times higher than that of Omniscan, and showed significantly higher MRI contrast enhancement than Omniscan in tumor. Meanwhile, the ODNP showed strong NIR light absorption and significant antitumor efficacy both in vitro and in vivo as a PPT agent. The ODNP with excellent MRI contrasting capability and PTT efficacy plus its facile synthesis and good biocompatibility are a very promising theranostic agent for MRI-mediated PTT.

Dual-channel NIR activatable theranostic prodrug for in vivo spatiotemporal tracking thiol-triggered chemotherapy.

Real-time tracking for where (W), when (W), and how (H) prodrugs are delivered and activated in vivo is a great challenge for prodrug development. Disulfide linkage-based prodrugs as well as their delivery systems have been studied extensively, but the WWH question in spatial and temporal (spatiotemporal) precision remains unanswered. Herein, we present a novel prodrug of camptothecin (CPT) linked to a near-infrared (NIR) cyanine dye via a disulfide linkage (Cy-S-CPT). The cleavage of the disulfide bond in Cy-S-CPT by endogenous glutathione (GSH) can activate the anti-cancer drug CPT and induce a remarkable fluorescence shift from 825 to 650 nm, thereby providing dual fluorescent channels to real-time track the prodrug biodistribution and activation in vivo. Impressively, the dual-channel NIR fluorescence bioimaging exhibits the pervasive drug distribution, i.e., the biodistribution of the intact prodrug was traced at the 825 nm-NIR fluorescence channel, whereas the activated drug was tracked at the 650 nm red fluorescence channel. In this way, we can overcome the blind spot in the metabolism kinetics of prodrugs in a certain organ or tissue. As demonstrated, the prodrug prompts activation in all the organs, particularly in the liver after an intravenous injection, and achieves predominant accumulation and activation in tumors at 24 h post injection. Cy-S-CPT loaded in PEG-PLA nanoparticles display significantly improved therapeutic efficacy and low side effects with respect to the clinical used drug CPT-11. As a consequence, the NIR spatiotemporal bioimaging in vivo with dual fluorescence channels allows the prodrug release profile to be extracted precisely, particularly in visualizing drug-released information from complex biological systems such as mice, thereby providing a unique opportunity to take insight into the relationship between theranosis and pharmacokinetics.