Liposome-Mediated Delivery of MERS Antigen Induces Potent Humoral and Cell-Mediated Immune Response in Mice.

The advancements in the field of nanotechnology have provided a great platform for the development of effective antiviral vaccines. Liposome-mediated delivery of antigens has been shown to induce the antigen-specific stimulation of the humoral and cell-mediated immune responses. Here, we prepared dried, reconstituted vesicles (DRVs) from DPPC liposomes and used them as the vaccine carrier system for the Middle East respiratory syndrome coronavirus papain-like protease (DRVs-MERS-CoV PLpro). MERS-CoV PLpro emulsified in the Incomplete Freund's Adjuvant (IFA-MERS-CoV PLpro) was used as a control. Immunization of mice with DRVs-MERS-CoV PLpro did not induce any notable toxicity, as revealed by the levels of the serum alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) in the blood of immunized mice. Immunization with DRVs-MERS-CoV PLpro induced greater antigen-specific antibody titer and switching of IgG1 isotyping to IgG2a as compared to immunization with IFA-MERS-CoV PLpro. Moreover, splenocytes from mice immunized with DRVs-MERS-CoV PLpro exhibited greater proliferation in response to antigen stimulation. Moreover, splenocytes from DRVs-MERS-CoV PLpro-immunized mice secreted significantly higher IFN-γ as compared to splenocytes from IFA-MERS-CoV PLpro mice. In summary, DRVs-MERS-CoV PLpro may prove to be an effective prophylactic formulation to prevent MERS-CoV infection.

Sorafenib and triptolide loaded cancer cell-platelet hybrid membrane-camouflaged liquid crystalline lipid nanoparticles for the treatment of hepatocellular carcinoma.

In addition to early detection, early diagnosis, and early surgery, it is of great significance to use new strategies for the treatment of hepatocellular carcinoma (HCC). Studies showed that the combination of sorafenib (SFN) and triptolide (TPL) could reduce the clinical dose of SFN and maintain good anti-HCC effect. But the solubility of SFN and TPL in water is low and both drugs have certain toxicity. Therefore, we constructed a biomimetic nanosystem based on cancer cell-platelet (PLT) hybrid membrane camouflage to co-deliver SFN and TPL taking advantage of PLT membrane with long circulation functions and tumor cell membrane with homologous targeting. The biomimetic nanosystem, SFN and TPL loaded cancer cell-PLT hybrid membrane-camouflaged liquid crystalline lipid nanoparticles ((SFN + TPL)@CPLCNPs), could simultaneously load SFN and TPL at the molar ratio of SFN to TPL close to 10:1. (SFN + TPL)@CPLCNPs achieved long circulation function and tumor targeting at the same time, promoting tumor cell apoptosis, inhibiting tumor growth, and achieving a better "synergy and attenuation effect", which provided new ideas for the treatment of HCC.

Reversing Multidrug Resistance by Inducing Mitochondrial Dysfunction for Enhanced Chemo-Photodynamic Therapy in Tumor.

Efficiency of standard chemotherapy is dramatically hindered by intrinsic multidrug resistance (MDR). Recently, to amplify therapeutic efficacy, photodynamic therapy (PDT)-induced mitochondrial dysfunction by decorating targeting moieties on nanocarriers has obtained considerable attention. Nevertheless, low targeting efficiency, complex synthesis routes, and difficulty in releasing contents become the major obstacles in further clinical application. Herein, an ingenious liposomal-based nanomedicine (L@BP) was fabricated by encapsulating a mitochondria-anchored photosensitizer (Cy-Br) and paclitaxel (PTX) for realizing enhanced cooperation therapy. At the cellular level, L@BP could hurdle endosomal traps to localize and implement PDT in mitochondria. Intriguingly, the PDT-induced in situ mitochondrial dysfunction led to intracellular ATP reduction, which triggered the downregulated P-glycoprotein transportation capacity and thus resulted in diminishing the efflux of chemotherapeutic agents and increasing drug uptake by drug-resistant cells. The prepared nanomedicine eminently accumulated in the tumor site and acquired enhanced therapeutic efficiency on PTX-resistant lung cancer cells, which possessed great potential in circumventing MDR tumors.

N-Acetyl-l-cysteine-Loaded Nanosystems as a Promising Therapeutic Approach Toward the Eradication of Pseudomonas aeruginosa Biofilms.

Bacterial biofilms are a major health concern, mainly due to their contribution to increased bacterial resistance to well-known antibiotics. The conventional treatment of biofilms represents a challenge, and frequently, eradication is not achieved with long-lasting administration of antibiotics. In this context, the present work proposes an innovative therapeutic approach that is focused on the encapsulation of N-acetyl-l-cysteine (NAC) into lipid nanoparticles (LNPs) functionalized with d-amino acids to target and disrupt bacterial biofilms. The optimized formulations presented a mean hydrodynamic diameter around 200 nm, a low polydispersity index, and a high loading capacity. These formulations were stable under storage conditions up to 6 months. In vitro biocompatibility studies showed a low cytotoxicity effect in fibroblasts and a low hemolytic activity in human red blood cells. Nevertheless, unloaded LNPs showed a higher hemolytic potential than NAC-loaded LNPs, which suggests a safer profile of the latter. The in vitro antibiofilm efficacy of the developed formulations was tested against Staphylococcus epidermidis (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) mature biofilms. The results showed that the NAC-loaded LNPs were ineffective against S. epidermidis biofilms, while a significant reduction of biofilm biomass and bacterial viability in P. aeruginosa biofilms were observed. In a more complex therapeutic approach, the LNPs were further combined with moxifloxacin, revealing a beneficial effect between the LNPs and the antibiotic against P. aeruginosa biofilms. Both alone and in combination with moxifloxacin, unloaded and NAC-loaded LNPs functionalized with d-amino acids showed a great potential to reduce bacterial viability, with no significant differences in the presence or absence of NAC. However, the presence of NAC in NAC-loaded functionalized LNPs shows a safer profile than the unloaded LNPs, which is beneficial for an in vivo application. Overall, the developed formulations present a potential therapeutic approach against P. aeruginosa biofilms, alone or in combination with antibiotics.

Protective Effect of Edaravone against Cationic Lipid-Mediated Oxidative Stress and Apoptosis.

Liposomes containing ionizable cationic lipids have been widely used for the delivery of nucleic acids such as small-interfering RNA and mRNA. The utility of cationic lipids with a permanent positive charge, however, is limited to in vitro transfection of cultured cells due to its dose-limiting toxic side effects observed in animals. Several reports have suggested that the permanently charged cationic lipids induce reactive oxygen species (ROS) and ROS-mediated toxicity in cells. We therefore hypothesized that the concomitant use of ROS inhibitor could reduce toxicity and improve drug efficacy. In this study, suppression of the cationic toxicity was evaluated using an ROS scavenger, edaravone, which is a low-molecular-weight antioxidant drug clinically approved for acute-phase cerebral infarction and amyotrophic lateral sclerosis. Cell viability assay in the mouse macrophage-like cell line RAW264 indicated that the concomitant use of edaravone were not able to suppress the cytotoxicity induced by cationic liposomes comprised of monovalent cationic lipid N-(1-[2,3-dioleyloxy]propyl)-N,N,N-trimethylammonium chloride (DOTMA) over a short period of time. Cationic lipids-induced necrosis was assumed to be involved in the cytotoxicity upon short-term exposure to cationic liposomes. On the other hand, the significant improvement of cell viability was observed when the short treatment with cationic liposomes was followed by exposure to edaravone for 24 h. It was also confirmed that apoptosis inhibition by ROS elimination might have contributed to this effect. These results suggest the utility of continuous administration with edaravone as concomitant drug for suppression of adverse reactions in therapeutic treatment using cationic liposomes.

Studies of anticancer activity in vivo and in vitro behaviors of liposomes encapsulated iridium(III) complex.

Iridium(III) complexes have gained great attention in cancer treatment in recent years. In this paper, we designed and synthesized a new iridium(III) complex [Ir(piq)2(DQTT)](PF6) Ir1 (piq = 1-phenylisoquinoline, DQTT = 12-(1,4-dihydroquinoxalin-6-yl)-4,5,9,14-tetraazabenzo[b]triphenylene). The Ir1-loaded PEGylated liposomes (Lipo-Ir1) were prepared using the ethanol injection method. The anticancer activity of the complex and Lipo-Ir1 against SGC-7901 (human gastric adenocarcinoma), A549 (human lung carcinoma), HeLa (human cervical carcinoma), HepG2 (human hepatocellular carcinoma), BEL-7402 (human hepatocellular carcinoma), and normal NIH3T3 (mouse embryonic fibroblasts) was tested by the MTT method. The complex Ir1 shows moderate or low cytotoxicity against the selected cancer cells, whereas the Lipo-Ir1 exhibits high anticancer activity toward the same cancer cells. The apoptosis induced by Lipo-Ir1 was assayed by flow cytometry and Lipo-Ir1 induced apoptosis through increasing intracellular reactive-oxygen species levels, decreasing mitochondrial membrane potential, further promoting cytochrome c release and causing the increase of level of intracellular Ca2+. Western blot was used to detect the changes in Bcl-2 family protein and PI3K/AKT pathway proteins. The cloning experiments demonstrated that the Lipo-Ir1 can effectively inhibit cell proliferation. In vivo experiments, Lipo-Ir1 inhibited tumor growth in xenograft nude mice, and the percentage of tumor growth inhibition in vivo was 75.70%. Overall, the liposomes Lipo-Ir1 exhibits higher anticancer activity than Ir1 under the same conditions. These results indicated that Lipo-Ir1 may be a valuable resource for cancer therapy.

Hybrid of niosomes and bio-synthesized selenium nanoparticles as a novel approach in drug delivery for cancer treatment.

The current study intends to investigate a novel drug delivery system (DDS) based on niosomes structure (NISM) and bovine serum albumin (BSA) which was formulated to BSA coated NISM (NISM-B). Also, selenium nanoparticles (SeNPs) have been prepared by BSA mediated biosynthesis. Finally, the NISM-B was hybridized with SeNPs and was formulated as NISM-B@SeNPs for drug delivery applications. Physicochemical properties of all samples were characterized by UV-Vis spectroscopy, FT-IR, DLS, FESEM, and EDX techniques. The cytotoxicity of all samples against A549 cell line was assessed by cell viability analysis and flow cytometry for apoptotic cells as well as RT-PCR for the expression of MDR-1, Bax, and Bcl-2 genes. Besides, in vivo biocompatibility was performed by LD50 assay to evaluate the acute toxicity. The proposed formulation has a regular spherical shape and approximately narrow size distribution with proper zeta-potential values; the proposed DDS revealed a good biocompatibility. The compound showed a significant cytotoxic effect against A549 cell line. Although the Bax/Bcl-2 expression ratio was significantly in NISM-B@SeNPs- treated cancer cells, the expression of MDR-1 was non-significantly lower in NISM-B@SeNPs-treated cancer cells. The obtained results suggest that the proposed DDS presents a promising approach for drug delivery, co-delivery and multifunctional biomedicine applications.

Flexible liposomal gel dual-loaded with all-trans retinoic acid and betamethasone for enhanced therapeutic efficiency of psoriasis.

BACKGROUND: Psoriasis is a chronic immune-mediated inflammatory skin disease without effective treatment. The utilization of all trans-retinoic acid (TRA) and betamethasone (BT) for the treatment of psoriasis is still facing difficulties, due to their relatively poor stability, limited skin permeation, and systemic side effects. Flexible liposomes are excellent in deeper skin permeation and reducing the side effects of drugs, which is promising for effective treatment of skin disorders. This work aimed to establish dual-loaded flexible liposomal gel for enhanced therapeutic efficiency of psoriasis based on TRA and BT. RESULTS: Flexible liposomes co-loaded with TRA and BT were successfully prepared in our study. The characterization examination revealed that flexible liposomes featured nano-sized particles (around 70 nm), high drug encapsulation efficiency (> 98%) and sustained drug release behaviors. Flexible liposomes remarkably increased the drug skin permeation and retention as compared with free drugs. Results on HaCaT cells suggested that flexible liposomes were nontoxic, and its cellular uptake has a time-dependent manner. In vivo studies suggested the topical application of TRA and BT dual-loaded liposomal gel had the best ability to reduce the thickness of epidermal and the level of cytokines (TNF-α and IL-6), largely alleviating the symptoms of psoriasis. CONCLUSIONS: Flexible liposomal gel dual-loaded with TRA and BT exerted a synergistic effect, which is a promising topical therapeutic for the treatment of psoriasis.

Magnetic Targeting and Ultrasound Activation of Liposome-Microbubble Conjugate for Enhanced Delivery of Anticancer Therapies.

Effective delivery of chemotherapeutics with minimal toxicity and maximal outcome is clinically important but technically challenging. Here, we synthesize a complex of doxorubicin (DOX)-loaded magneto-liposome (DOX-ML) microbubbles (DOX-ML-MBs) for magnetically responsive and ultrasonically sensitive delivery of anticancer therapies with enhanced efficiency. Citrate-stabilized iron oxide nanoparticles (MNs) of 6.8 ± 1.36 nm were synthesized, loaded with DOX in the core of oligolamellar vesicles of 172 ± 9.2 nm, and covalently conjugated with perfluorocarbon (PFC)-gas-loaded microbubbles to form DOX-ML-MBs of ∼4 µm. DOX-ML-MBs exhibited significant magnetism and were able to release chemotherapeutics and DOX-MLs instantly upon exposure to ultrasound (US) pulses. In vitro studies showed that DOX-ML-MBs in the presence of US pulses promoted apoptosis and were highly effective in killing both BxPc-3 and Panc02 pancreatic cancer cells even at a low dose. Significant reduction in the tumor volume was observed after intravenous administration of DOX-ML-MBs in comparison to the control group in a pancreatic cancer xenograft model of nude mice. Deeply penetrated iron oxide nanoparticles throughout the magnetically targeted tumor tissues in the presence of US stimulation were clearly observed. Our study demonstrated the potential of using DOX-ML-MBs for site-specific targeting and controlled drug release. It opens a new avenue for the treatment of pancreatic cancer and other tissue malignancies where precise delivery of therapeutics is necessary.

Preparation, Characterization, and Pharmacokinetic Study of a Novel Long-Acting Targeted Paclitaxel Liposome with Antitumor Activity.

BACKGROUND: Breast cancer is the leading cause of cancer death in women. Chemotherapy to inhibit the proliferation of cancer cells is considered to be the most important therapeutic strategy. The development of long-circulating PEG and targeting liposomes is a major advance in drug delivery. However, the techniques used in liposome preparation mainly involve conventional liposomes, which have a short half-life, high concentrations in the liver and spleen reticuloendothelial system, and no active targeting. METHODS: Four kinds of paclitaxel liposomes were prepared and characterized by various analytical techniques. The long-term targeting effect of liposomes was verified by fluorescence detection methods in vivo and in vitro. Pharmacokinetic and acute toxicity tests were conducted in ICR mice to evaluate the safety of different paclitaxel preparations. The antitumor activity of ES-SSL-PTX was investigated in detail using in vitro and in vivo human breast cancer MCF-7 cell models. RESULTS: ER-targeting liposomes had a particle size of 137.93±1.22 nm and an acceptable encapsulation efficiency of 88.07±1.25%. The liposome preparation is best stored at 4°C, and is stable for up to 48 hrs. Cytotoxicity test on MCF-7 cells demonstrated the stronger cytotoxic activity of liposomes in comparison to free paclitaxel. We used the near-infrared fluorescence imaging technique to confirm that ES-SSL-PTX was effectively targeted and could quickly and specifically identify the tumor site. Pharmacokinetics and acute toxicity in vivo experiments were carried out. The results showed that ES-SSL-PTX could significantly prolong the half-life of the drug, increase its circulation time in vivo, improve its bioavailability and reduce its toxicity and side effects. ES-SSL-PTX can significantly improve the pharmacokinetic properties of paclitaxel, avoid allergic reaction of the original solvent, increase antitumor efficacy and reduce drug toxicity and side effects. CONCLUSION: ES-SSL-PTX has great potential for improving the treatment of breast cancer, thereby improving patient prognosis and quality of life.

Toll like-receptor agonist Pam3Cys modulates the immunogenicity of liposomes containing the tuberculosis vaccine candidate H56.

A major roadblock in the development of novel vaccines is the formulation and delivery of the antigen. Liposomes composed of a dimethyldioctadecylammonium (DDA) backbone and the adjuvant trehalose-6-6-dibehenate (TDB, termed "cationic adjuvant formulation (CAF01)", promote immunogenicity and protective efficacy of vaccines, most notably against infection with Mycobacterium tuberculosis. Specifically, the multicomponent antigen H56 delivered by CAF01 protects against tuberculosis in mice. Here we investigated whether the inclusion of immune-modulatory adjuvants into CAF01 modulates the immunogenicity of H56/CAF01 in vitro and in vivo. Based on our recent findings we selected the active sequence of the mycobacterial 19 kDa lipoprotein, Pam3Cys, which interacts with Toll like receptor 2 to induce an antimicrobial pathway. H56/CAF01-Pam3Cys liposomes were characterized for Pam3Cys incorporation, size, toxicity and activation of primary human macrophages. Macrophages efficiently take up H56/CAF01-Pam3Cys and trigger the release of significantly higher levels of TNF, IL-12 and IL-10 than H56/CAF01 alone. To evaluate the immunogenicity in vivo, we immunized mice with H56/CAF01-Pam3Cys and measured the release of IFN-γ and IL-17A by lymph node cells and spleen cells. While the antigen-specific production of IFN-γ was reduced by inclusion of Pam3Cys into H56/CAF01, the levels of IL-17A remained unchanged. In agreement with this finding, the concentration of the IFN-γ-associated IgG2a antibodies in the serum was lower than in H56/CAF01 immunized animals. These results provide proof of concept that Toll like-receptor agonist can be included into liposomes to modulate immune responses. The discordant results between the in vitro studies with human macrophages and in vivo studies in mice highlight the relevance and complexity of comparing immune responses in different species.

Improved Antitumor Activity of Novel Redox-Responsive Paclitaxel-Encapsulated Liposomes Based on Disulfide Phosphatidylcholine.

The microtubule inhibitor paclitaxel (PTX) is used to treat a wide range of solid tumors. Due to the poor aqueous solubility of PTX, a continuous demand for safe, efficient PTX formulations with improved antitumor activity exists. Here, we report a novel form of redox-sensitive paclitaxel (PTX)-encapsulated liposomes based on the previously developed disulfide phosphatidylcholine (SS-PC). PTX-loaded stealth liposomes (PTX/SS-LP) composed of SS-PC, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-PEG2000 (DSPE-PEG2000), and cholesterol were prepared using the reverse-phase evaporation method. The characterization of the PTX/SS-LP liposomes using dynamic light scattering and transmission electron microscopy confirmed their uniform particle size and typical unilamellar vesicle structure with an average bilayer thickness of approximately 4 nm. Changes in the size and morphology as well as the rapid release of PTX triggered by the addition of dithiothreitol revealed the redox sensitivity of PTX/SS-LP. Finally, evaluations in MCF-7 and A549 cells in vitro and in BALB/c mice in vivo revealed the improved anticancer efficiency, biodistribution, and safety of PTX/SS-LP compared with those of Taxol and nonredox-sensitive PTX/LP. In conclusion, PTX/SS-LP displays a redox-responsive release of paclitaxel with improved antitumor activity and has great potential as a next-generation stealth liposomal PTX delivery system.

Comparison between Lipofectamine RNAiMAX and GenMute transfection agents in two cellular models of human hepatoma.

RNA interference is a powerful approach to understand gene function both for therapeutic and experimental purposes. Since the lack of knowledge in the gene silencing of various hepatic cell lines, this work was aimed to compare two transfection agents, the liposome-based Lipofectamine™ RNAiMAX and the HepG2-specific, polymer-based GenMute™, in two cellular models of human hepatoma, HepG2 and Huh7.5. In the first part, we assessed transfection efficiency of a fluorescent Cy3-labeled negative control siRNA by cell imaging analysis; we found that cells treated with GenMute present a higher uptake of the fluorescent negative control siRNA when compared to Lipofectamine RNAiMAX-transfected cells, both in HepG2 and in Huh7.5 cells. In the second part, we evaluated GAPDH silencing with the two transfection reagents by RT-PCR similar GAPDH mRNA expression after each transfection treatment. Finally, we measured cell viability by the MTT assay, observing that cells transfected with GenMute have higher viability with respect to Lipofectamine RNAiMAX-administered cells. These results suggest that GenMute reagent might be considered the most suitable transfection agent for hepatic gene silencing.

The Impact of Alkyl-Chain Purity on Lipid-Based Nucleic Acid Delivery Systems - Is the Utilization of Lipid Components with Technical Grade Justified?

The physicochemical properties and transfection efficacies of two samples of a cationic lipid have been investigated and compared in 2D (monolayers at the air/liquid interface) and 3D (aqueous bulk dispersions) model systems using different techniques. The samples differ only in their chain composition due to the purity of the oleylamine (chain precursor). Lipid 8 (using the oleylamine of technical grade for cost-efficient synthesis) shows lateral phase separation in the Langmuir layers. However, the amount of attached DNA, determined by IRRAS, is for both samples the same. In 3D systems, lipid 8 p forms cubic phases, which disappear after addition of DNA. At physiological temperatures, both lipids (alone and in mixture with cholesterol) assemble to lamellar aggregates and exhibit comparable DNA delivery efficiency. This study demonstrates that non-lamellar structures are not compulsory for high transfection rates. The results legitimate the utilization of oleyl chains of technical grade in the synthesis of cationic transfection lipids.

A novel niosome formulation for encapsulation of anthocyanins and modelling intestinal transport.

The bioavailability of drugs can be improved by regulating the structural properties, particularly lipoid systems, such as niosomes, can increase cellular uptake. Herein, we optimized double emulsion and niosomal formulations for encapsulating anthocyanin-rich black carrot extract. Nanoparticles obtained by selected formulation were characterized in terms of morphology, particle size, drug encapsulation efficiency, in vitro release and cytotoxicity. The optimum conditions for niosomal formulation were elicited as 30 mg of cholesterol, 150 mg of Tween 20 and feeding time of 1 min at a stirring rate of 900 rpm yielding the lowest average particle size of 130 nm. In vitro release data showed the majority of the encapsulated anthocyanins were released at the end of 10 h. A mathematical model was developed to estimate the absorption of anthocyanins released from niosomes and cytotoxicity was assessed against neuroblastoma. Overall, these findings suggest that niosomal vesicles might be suitable delivery systems for anthocyanins.

Toxicological exploration of peptide-based cationic liposomes in siRNA delivery.

The toxicology of cationic liposomes was explored to advance clinical trials of liposome-mediated gene therapy through the analysis of a peptide cationic liposome with DOTAP as a positive control. We first investigated the delivery of luciferase siRNA by several peptide liposomes in mice bearing lung cancer A549 cell xenografts. Of these, a cationic liposome (CDO14) was selected for further investigation. CDO14 efficiently mediated IGF-1R-siRNA delivery and inhibited the growth of the A549 cell xenografts. The in vivo toxicity and toxicological mechanisms of the selected liposome were evaluated to assess its potential utility for gene delivery. Specifically, the effects of CDO14 on mouse body weight, hematology, urine, serum biochemical indices, and histopathology were measured in acute toxicity and subchronic toxicity tests. CDO14 showed limited toxicological effects at low dosages although it induced pulmonary inflammation and liver injury at higher dosages. The toxicity of CDO14 was lower than that of DOTAP, and the toxicity of CDO14 did not change when complexed with siRNA. The pulmonary inflammation induced by CDO14 occurred via expressional up-regulation of the pro-inflammatory cytokines TNF-α and IL-6, and expressional down-regulation of the anti-inflammatory cytokine IL-10. Liver injury induced by CDO14 was mediated by the JAK2-STAT3 signaling pathway. Lastly, CDO14 did not affect the expression of apoptosis-related proteins in normal liver cells, suggesting that it did not induce apoptosis of normal cells. The toxicological results demonstrate that peptide-based headgroups in lipids are superior to those with quaternary ammonium headgroups that are used as gene vectors for cancer therapy.

Targeted Myocardial Hypoxia Imaging Using a Nitroreductase-Activatable Near-Infrared Fluorescent Nanoprobe.

Development of a highly selective and sensitive imaging probe for accurate detection of myocardial hypoxia will be helpful to estimate the degree of ischemia and subsequently guide personalized treatment. However, an efficient optical approach for hypoxia monitoring in myocardial ischemia is still lacking. In this work, a cardiomyocyte-specific and nitroreductase-activatable near-infrared nanoprobe has been developed for selective and sensitive imaging of myocardial hypoxia. The nanoprobe is a liposome-based nanoarchitecture which is functionalized with a peptide (GGGGDRVYIHPF) for targeting heart cells and encapsulating a nitrobenzene-substituted BODIPY for nitroreductase imaging. The nanoprobe can specifically recognize and bind to angiotensin II type 1 receptor that is overexpressed on the ischemic heart cells by the peptide and is subsequently uptaken into heart cells, in which the probe is released and activated by hypoxia-related nitroreductase to produce fluorescence emission at 713 nm. The in vitro response of the nanoprobe toward nitroreductase resulted in 55-fold fluorescence enhancement with the limit of detection as low as 7.08 ng/mL. Confocal fluorescence imaging confirmed the successful uptake of nanoprobe by hypoxic heart cells and intracellular detection of nitroreductase. More significantly, in vivo imaging of hypoxia in a murine model of myocardial ischemia was achieved by the nanoprobe with high sensitivity and good biocompatibility. Therefore, this work presents a new tool for targeted detection of myocardial hypoxia and will promote the investigation of the hypoxia-related physiological and pathological process of ischemic heart disease.

A novel gemcitabine derivative-loaded liposome with great pancreas-targeting ability.

Gemcitabine (Gem) is a standard first-line treatment for pancreatic cancer (PC). However, its chemotherapeutic efficacy is hampered by various limitations such as short half-life, metabolic inactivation, and lack of tumor localizing. We previously synthesized a lipophilic Gem derivative (Gem formyl hexadecyl ester, GemC16) that exhibited improved antitumor activity in vitro. In this study, a target ligand N,N-dimethyl-1,3-propanediamine was conjugated to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[hydroxyl succinimidyl (polyethylene glycol-2000)] (DSPE-PEG-NHS) to form DSPE-PEG-2N. Then, pancreas-targeting liposomes (2N-LPs) were prepared using the film dispersion-ultrasonic method. GemC16-loaded 2N-LPs displayed near-spherical shapes with an average size distribution of 157.2 nm (polydispersity index (PDI) = 0.201). The encapsulation efficiency of GemC16 was up to 97.3% with a loading capacity of 8.9%. In human PC cell line (BxPC-3) and rat pancreatic acinar cell line (AR42J), cellular uptake of 2N-LPs was significantly enhanced compared with that of unmodified PEG-LPs. 2N-LPs exhibited more potent in vitro cytotoxicity against BxPC-3 and AR42J cell lines than PEG-LPs. After systemic administration in mice, 2N-LPs remarkably increased drug distribution in the pancreas. In an orthotopic tumor mouse model of PC, GemC16-bearing liposomes were more effective in preventing tumor growth than free GemC16. Among these treatments, 2N-LPs showed the best curative effect. Together, 2N-LPs represent a promising nanocarrier to achieve pancreas-targeting drug delivery, and this work would provide new ideas for the chemotherapy of PC.

Chemiluminescent liposomes as a theranostic carrier for detection of tumor cells under oxidative stress.

Hydrogen peroxide (H2O2) is one of the main source of oxidative stress and a typical marker of reactive oxygen species (ROS)-associated diseases. Therefore, selective detection and scavenging of overproduced H2O2 provide enormous benefits to the successful treatment of ROS-related diseases. The authors took advantage of this property to detect cancer cells using chemiluminescent peroxyoxalate reaction. Here, a new contrast agent presented for hydrogen peroxide, termed peroxyoxalate liposomes, which detect hydrogen peroxide through chemiluminescence reaction, and have the physical/chemical properties needed for imaging applications. The peroxyoxalate liposomes are composed of Bis (2, 4, 6-trichlorphenyl) oxalate (TCPO) and curcumin as fluorophore. Experimental factors such as TCPO, imidazole, hydrogen peroxide and curcumin concentration were optimized. Moreover, application of curcumin makes it possible to design a system for selective tumor destruction. In the reaction of peroxyoxalate, it acts as an oxalate activator with intracellular hydrogen peroxide and experiences excitation as a result of the reaction. In addition, curcumin also acts as a photosensitizer (PS) causing cell damage. In the optimum conditions, the measurable concentration range of 0.86-220 µM of hydrogen peroxide were evaluated from the linear calibration curve with satisfactory RSD% and corresponding detection limits of 650 nM. Therefore, it has the sensitivity needed to detect physiological concentrations of hydrogen peroxide. Moreover, cellular uptake experiments showed that the liposomes enhance extravasation into permeable membranes and significantly increased the bioavailability of curcumin.

Toxicologic evaluation of repetitive 4-week intravenous injections of midkine antisense oligonucleotide nanoliposomes in rats.

Midkine antisense oligonucleotide (MK-ASODN) nanoliposomes have previously been shown to have inhibitory activity against hepatocellular carcinoma growth. Herein we report the 4-week sub-chronic toxicity of MK-ASODN nanoliposomes in SD rats. The adverse effects included loss of body weight gain and food consumption, peri-rhinal bleeding, piloerection, peri-anal filth, and kidney, liver, spleen, thymus, lung, and injection site lesions at high doses. Macroscopic changes were observed in the kidneys of the high-dose group, accompanied by a variation in urine protein and white blood cells, blood urea nitrogen, and serum creatinine. The increased spleen and liver coefficient, and the variation in circulating white blood cells, lymphocytes, and eosinophils in the high-dose group demonstrated that inflammation was caused by MK-ASODN nanoliposomes and was consistent with the macroscopic changes in the spleen and liver. The main necropsy findings of the animals that died were macroscopic changes in the lung. No severe toxic effects or mortalities occurred in the low- and medium-dose groups. However, a No Adverse Effect Level (NOAEL) was not identified since there were changes in organs deemed to be adverse at all dose levels. Thus, the maximum tolerated dose of MK-ASODN nanoliposomes for rats was considered to be 6 mg/kg/day.