Development of fluorous lipid-based nanobubbles for efficiently containing perfluoropropane

Application of ultrasonic cavitation combined with rapid pathological tissue processing method of novel environmental protection reagents in pathological diagnosis

To investigate the effect of pretreatment of tumor biopsy specimens using fixed, dehydrated and transparent three-in-one composite environmental protection reagent ultrasound tissue rapid processing technique on subsequent detection. From April 2020 to October 2020, a total of 100 cases including breast, stomach and lung tissues were submitted to our diagnosis, and 3 specimens were collected from each specimen and divided into the control group (traditional biopsy tissue processing method), experimental group 1 (3.7% neutral buffered formaldehyde fixation, compound environmental protection reagent rapid ultrasound tissue processing technique, processing temperature 48 °C, time 20 minutes/time, twice, wax immersion temperature 62 °C, time 25 minutes) and experimental group 2 (3.7% neutral buffered formaldehyde fixation, compound environmental protection reagent rapid ultrasound tissue processing technique, processing temperature 50 °C, time 15 min/time, twice, Wax dipping temperature 64 °C, time 20 minutes). The effects of different treatments on hematoxylin eosin section, immunohistochemistry (IHC) and molecular pathological examination were analyzed. The detection results of hematoxylin eosin, fluorescence in situ hybridization and IHC against human epidermal growth factor receptor 2 and epidermal growth factor receptor gene mutation in the experimental group were completely consistent with those in the control group. There was no significant difference in the results between experiment 1 and experiment 2 groups. The rapid processing technique of ultrasound tissue with compound environmental protection reagent can be applied to the rapid detection of tumor biopsy specimens, and different processing temperatures and durations have no significant effect on the accuracy of HE staining, IHC, fluorescence in situ hybridization and gene mutation detection.

Advances in lipid-based carriers for cancer therapeutics: Liposomes, exosomes and hybrid exosomes

Cancer has recently surpassed heart disease as the leading cause of deaths worldwide for the age group 45-65 and has been the primary focus for biomedical researchers. Presently, the drugs involved in the first-line cancer therapy are raising concerns due to high toxicity and lack of selectivity to cancer cells. There has been a significant increase in research with innovative nano formulations to entrap the therapeutic payload to enhance efficacy and eliminate or minimize toxic effects. Lipid-based carriers stand out due to their unique structural properties and biocompatible nature. The two main leaders of lipid-based drug carriers: long known liposomes and comparatively new exosomes have been well-researched. The similarity between the two lipid-based carriers is the vesicular structure with the core's capability to carry the payload. While liposomes utilize chemically derived and altered phospholipid components, the exosomes are naturally occurring vesicles with inherent lipids, proteins, and nucleic acids. More recently, researchers have focused on developing hybrid exosomes by fusing liposomes and exosomes. Combining these two types of vesicles may offer some advantages such as high drug loading, targeted cellular uptake, biocompatibility, controlled release, stability in harsh conditions and low immunogenicity.

Stimuli-responsive nanobubbles for biomedical applications

Stimuli-responsive nanobubbles have received increased attention for their application in spatial and temporal resolution of diagnostic techniques and therapies, particularly in multiple imaging methods, and they thus have significant potential for applications in the field of biomedicine. This review presents an overview of the recent advances in the development of stimuli-responsive nanobubbles and their novel applications. Properties of both internal- and external-stimuli responsive nanobubbles are highlighted and discussed considering the potential features required for biomedical applications. Furthermore, the methods used for synthesis and characterization of nanobubbles are outlined. Finally, novel biomedical applications are proposed alongside the advantages and shortcomings inherent to stimuli-responsive nanobubbles.

Application of Direct Sonoporation from a Defined Surface Area of the Peritoneum: Evaluation of Transfection Characteristics in Mice

In the present study, we developed a sonoporation system, namely “direct sonoporation”, for transfecting the peritoneum from a defined surface area to avoid systematic side effects. Here, the transfection characteristics are explained because there is less information about direct sonoporation. Naked pDNA and nanobubbles were administered to diffusion cell attached to the visceral and parietal peritoneum from the liver and peritoneal wall surface, respectively. Then, ultrasound was irradiated. Direct sonoporation showed a higher transfection efficacy at the applied peritoneum site from the liver surface while other sites were not detected. Moreover, transgene expression was observed in the peritoneal mesothelial cells (PMCs) at the applied peritoneum site. No abnormality was observed in the inner part of the liver. Although transgene expression of the visceral peritoneum was tenfold higher than that of the parietal peritoneum, transgene expression was observed in the PMCs on both the applied peritoneum sites. These results suggest that direct sonoporation is a site-specific transfection method of the PMCs on the applied peritoneum site without transgene expression at other sites and show little toxicity in the inner tissues at the applied site via cavitation energy. This information is valuable for the development of an intraperitoneal sonoporation device for treatment of peritoneal diseases such as peritoneal fibrosis.

CAIX aptamer-functionalized targeted nanobubbles for ultrasound molecular imaging of various tumors

Purpose

Targeted nanobubbles can penetrate the tumor vasculature and achieve ultrasound molecular imaging (USMI) of tumor parenchymal cells. However, most targeted nanobubbles only achieve USMI of tumor parenchymal cells from one organ, and their distribution, loading ability, and binding ability in tumors are not clear. Therefore, targeted nanobubbles loaded with carbonic anhydrase IX (CAIX) aptamer were fabricated for USMI of various tumors, and the morphological basis of USMI with targeted nanobubbles was investigated.

Materials and methods

The specificity of CAIX aptamer at the cellular level was measured by immunofluorescence and flow cytometry. Targeted nanobubbles loaded with CAIX aptamer were prepared by a maleimidethiol coupling reaction, and their binding ability to CAIX-positive tumor cells was analyzed in vitro. USMI of targeted and non-targeted nanobubbles was performed in tumor-bearing nude mice. The distribution, loading ability, and binding ability of targeted nanobubbles in xenograft tumor tissues were demonstrated by immunofluorescence.

Results

CAIX aptamer could specifically bind to CAIX-positive 786-O and Hela cells, rather than CAIX-negative BxPC-3 cells. Targeted nanobubbles loaded with CAIX aptamer had the advantages of small size, uniform distribution, regular shape, and high safety, and they could specifically accumulate around 786-O and Hela cells, while not binding to BxPC-3 cells in vitro. Targeted nanobubbles had significantly higher peak intensity and larger area under the curve than non-targeted nanobubbles in 786-O and Hela xenograft tumor tissues, while there was no significant difference in the imaging effects of targeted and non-targeted nanobubbles in BxPC-3 xenograft tumor tissues. Immunofluorescence demonstrated targeted nanobubbles could still load CAIX aptamer after penetrating the tumor vasculature and specifically binding to CAIX-positive tumor cells in xenograft tumor tissues.

Conclusion

Targeted nanobubbles loaded with CAIX aptamer have a good imaging effect in USMI of tumor parenchymal cells, and can improve the accuracy of early diagnosis of malignant tumors from various organs.

Discovery of a sugar-based nanoparticle universally existing in boiling herbal water extracts and their immunostimulant effect

Herbal medicine is mainly prepared from boiling herbal water extracts. Many epoch-making immunosuppressant drugs, such as glycyrrhizic acid (old example) and FTY720 (current example), were developed from herbal secondary metabolites in the boiling water extract by partition with organic solvents. However, few immunostimulants have been discovered by this method. Instead of the usual method, we aimed to find a novel immunostimulant component by two unique methods in the research of herbal medicine: ultracentrifugation and electron microscopy. The immunostimulant was not a secondary metabolite, as expected, but the structure was a nanoparticle formed by a polysaccharide. In addition, we clarified the immune effect of the nanoparticle. Intake of the nanoparticle by phagocytosis resulted in immunostimulant effects by increasing the genes and proteins of inflammatory cytokines in macrophage cells. The immunostimulant effects were inhibited by a phagocytosis inhibitor, cytochalasin D. To the best of our knowledge, this study is the first to describe the discovery of a nanoparticle in boiling herbal water extracts and its immunostimulant properties. This study will provide additional understanding of the efficacy of herbal medicine, in that the immunostimulant nanoparticle universally exists in boiling herbal water extracts. Thus, traditional herbal medicine may be an oldest known nanomedicine. Furthermore, this study suggests that the immunostimulant nanoparticle simply can be obtained from herbal medicine only by ultracentrifugation. We hope that this simple strategy will substantially contribute to drug development, including vaccine adjuvant, in the future.

•

Nanoparticles are universally present in boiling herbal water extracts.

•

Nanoparticles are obtained from these extracts by ultracentrifugation.

•

Nanoparticles are mainly composed of polysaccharides.

•

Nanoparticles have an immunostimulatory effect on macrophage cells.

•

This effect is exhibited by the phagocytosis of exogenous nanoparticles.

Efficient gene transfection to the brain with ultrasound irradiation in mice using stabilized bubble lipopolyplexes prepared by the surface charge regulation method

Introduction

We previously developed anionic ternary bubble lipopolyplexes, an ultrasound-responsive carrier, expecting safe and efficient gene transfection. However, bubble lipopolyplexes have a low capacity for echo gas (C₃F₈) encapsulation (EGE) in nonionic solution such as 5% glucose. On the other hand, we were able to prepare bubble lipopolyplexes by inserting phosphate-buffered saline before C₃F₈ encapsulation. Surface charge regulation (SCR) by electrolytes stabilizes liposome/plasmid DNA (pDNA) complexes by accelerated membrane fusion. Considering these facts, we hypothesized that SCR by electrolytes such as NaCl would promote C₃F₈ encapsulation in bubble lipopolyplexes mediated by accelerated membrane fusion. We defined this hypothesis as SCR-based EGE (SCR-EGE). Bubble lipopolyplexes prepared by the SCR-EGE method (SCR-EGE bubble lipopolyplexes) are expected to facilitate the gene transfection because of the high amount of C₃F₈. Therefore, we applied these methods for gene delivery to the brain and evaluated the characteristics of transgene expression in the brain.

Methods

First, we measured the encapsulation efficiency of C₃F₈ in SCR-EGE bubble lipopolyplexes. Next, we applied these bubble lipopolyplexes to the mouse brain; then, we evaluated the transfection efficiency. Furthermore, three-dimensional transgene distribution was observed using multicolor deep imaging.

Results

SCR-EGE bubble lipopolyplexes had a higher C₃F₈ content than conventional bubble lipopolyplexes. In terms of safety, SCR-EGE bubble lipopolyplexes possessed an anionic potential and showed no aggregation with erythrocytes. After applying SCR-EGE bubble lipopolyplexes to the brain, high transgene expression was observed by combining with ultrasound irradiation. As a result, transgene expression mediated by SCR-EGE bubble lipopolyplexes was observed mainly on blood vessels and partially outside of blood vessels.

Conclusion

The SCR-EGE method may promote C₃F₈ encapsulation in bubble lipopolyplexes, and SCR-EGE bubble lipopolyplexes may be potent carriers for efficient and safe gene transfection in the brain, especially to the blood vessels.

The development of mechanically formed stable nanobubbles intended for sonoporation-mediated gene transfection

In this study, stable nano-sized bubbles (nanobubbles [NBs]) were produced using the mechanical agitation method in the presence of perfluorocarbon gases. NBs made with perfluoropropane had a smaller size (around 400 nm) compared to that of those made with perfluorobutane or nitrogen gas. The lipid concentration in NBs affected both their initial size and post-formulation stability. NBs formed with a final lipid concentration of 0.5 mg/ml tended to be more stable, having a uniform size distribution for 24 h at room temperature and 50 h at 4 °C. In vitro gene expression revealed that NBs/pDNA in combination with ultrasound (US) irradiation had significantly higher transfection efficacy in colon C26 cells. Moreover, for in vivo gene transfection in mice left limb muscles, there was notable local transfection activity by NBs/pDNA when combined with US irradiation. In addition, the aged NBs kept at room temperature or 4 °C were still functional at enhancing gene transfection in mice. We succeeded in preparing stable NBs for efficient in vivo gene transfection, using the mechanical agitation method.

Targeted Soft Biodegradable Glycine/PEG/RGD-Modified Poly(methacrylic acid) Nanobubbles as Intelligent Theranostic Vehicles for Drug Delivery

The development of multifunctional ultrasound contrast agents has inspired considerable interest in the application of biomedical imaging and anticancer therapeutics. However, combining multiple components that can preferentially accumulate in tumors in a nanometer scale poses one of the major challenges in targeting drug delivery for theranostic application. Herein, reflux-precipitation polymerization, and N-(3-(dimethylamino)propyl)-N'-ethylcarbodiimide-meditated amidation reaction were introduced to effectively generate a new type of soft glycine/poly(ethylene glycol) (PEG)/RGD-modified poly(methacrylic acid) nanobubbles with a uniform morphology and desired particle size (less than 100 nm). Because of the enhanced biocompatibility resulting from the glycine modification, over 80% of the cells survived, even though the dosage of glycine-modified polymeric nanobubbles was up to 5 mg/mL. By loading doxorubicin as an anticancer drug and perfluorohexane as an ultrasound probe, the resulting glycine/PEG/RGD-modified nanobubbles showed remarkable cancer therapeutic efficacy and a high quality of ultrasonic imaging; thus, the ultrasonic signal exhibited a 1.47-fold enhancement at the tumor site after intravenous injection. By integrating diagnostic and therapeutic functions into a single nanobubble, the new type of theranostic nanobubbles offers a promising strategy to monitor the therapeutic effects, giving important insights into the ultrasound-traced and enhanced targeting drug delivery in biomedical applications.

Thermoresponsive pegylated bubble liposome nanovectors for efficient siRNA delivery via endosomal escape

AIM

Improving the delivery of siRNA into cancer cells via bubble liposomes. Designing a thermoresponsive pegylated liposome through the introduction of ammonium bicarbonate salt into liposomes so as to control their endosomal escape for gene therapy.

METHODS

A sub-200 nm nanovector was fully characterized and examined for cellular uptake, cytotoxicity, endosomal escape and gene silencing.

RESULTS

The siRNA-liposomes were internalized into cancer cells within 5 min and then released siRNAs in the cytosol prior to lysosomal degradation upon external temperature elevation. This was confirmed by confocal bioimaging and gene silencing reaching up to 90% and further demonstrated by the protein inhibition of both target genes.

CONCLUSION

The thermoresponsiveness of ammonium bicarbonate containing liposomes enabled the rapid endosomal escape of the particles and resulted in an efficient gene silencing.

End-chain fluorination of polyesters favors perfluorooctyl bromide encapsulation into echogenic PEGylated nanocapsules

Fluorination of polyesters favors the encapsulation efficiency of perfluorooctyl bromide into nanocapsules.

Catanionic lipid nanosystems improve pharmacokinetics and anti-lung cancer activity of curcumin

Novel catanionic lipid nanosystems (CLNs) incorporating curcumin (CCM) were developed, and improvements in pharmacokinetics and enhanced anti-lung cancer activity were observed. CCM was present in a lipid matrix surrounded by cationic, anionic and zwitterionic surfactants, forming the core-shell nanosystems. Compared with free CCM, the CCM-CLNs had much higher oral and intravenous bioavailabilities due to enhanced absorption and reduced clearance. The CCM-CLNs exhibited greater cytotoxicity in Lewis lung cancer (LLC) cells, which might have been due to increased antiproliferative, proapoptotic and anti-invasive activities and induction of cell cycle arrest. The CCM-CLNs increased the antitumor efficacy of CCM and decreased the tumor growth rate in tumor-bearing mice. This is the first report of induction of apoptosis in LLC cells by CCM through the PI3K/Akt/FoxO1/Bim signaling pathway. Catanionic lipid nanocarriers show promise for the therapeutic delivery of insoluble anti-tumor drugs.