Oxygen transport to mammalian cell and bacteria using nano-sized liposomes encapsulating oxygen molecules.

Hypoxic microenvironments emerge as tumor grow, leading to the over-expression and stabilization of hypoxia-inducible factor 1-alpha (HIF-1α). HIF-1α lowers the sensitization against chemotherapy, radiation therapy and photodynamic therapy in cancer. In this study, nano-sized oxygen carrier, namely oxygen dissolved nanoliposome (ODL) was synthesized, and oxygen was efficiently delivered to different types of mammalian cells to help relieve hypoxia. ODL confirmed that oxygen was released without inducing toxicity to cells. After artificially creating hypoxia in cancer cells, normal cells, and immune cells; various parameters such as cell morphology, HIF-1α expression, and degree of hypoxia were examined. The cellular environment was found to be altered by treatment with the ODL. Under hypoxia, the shape of the cells changed, and the cells began to die. After treatment with the ODL, the degree of hypoxia was reduced, indicating that HIF-1α expression and the rate of cell death decreased. Furthermore, bacteria proliferation was observed with the ODL. Therefore, ODL can be used for oxygen delivery platform in cancer therapy. ODL has a potential application in other microorganisms which needs future research.

Hypoxia-Responsive Oxygen Nanobubbles for Tissues-Targeted Delivery in Developing Tooth Germs.

Hypoxia is a state of inadequate supply of oxygen. Increasing evidence indicates that a hypoxic environment is strongly associated with abnormal organ development. Oxygen nanobubbles (ONBs) are newly developed nanomaterials that can deliver oxygen to developing tissues, including hypoxic cells. However, the mechanisms through which nanobubbles recover hypoxic tissues, such as developing tooth germs remain to be identified. In this study, tooth germs were cultured in various conditions: CO2 chamber, hypoxic chamber, and with 20% ONBs for 3 h. The target stages were at the cap stage (all soft tissue) and bell stage (hard tissue starts to form). Hypoxic tooth germs were recovered with 20% ONBs in the media, similar to the tooth germs incubated in a CO2 chamber (normoxic condition). The tooth germs under hypoxic conditions underwent apoptosis both at the cap and bell stages, and ONBs rescued the damaged tooth germs in both the cap and bell stages. Using kidney transplantation for hard tissue formation in vivo, amelogenesis and dentinogenesis imperfecta in hypoxic conditions at the bell stage were rescued with ONBs. Furthermore, glucose uptake by tooth germs was highly upregulated under hypoxic conditions, and was restored with ONBs to normoxia levels. Our findings indicate that the strategies to make use of ONBs for efficient oxygen targeted delivery can restore cellular processes, such as cell proliferation and apoptosis, glucose uptake, and hypomineralization in hypoxic environments.

Exosome-based photoacoustic imaging guided photodynamic and immunotherapy for the treatment of pancreatic cancer.

Exosomes, which are released from all cells and take part in cell-to-cell communication, have been utilized as drug delivery vehicles in many recent studies. Immunotherapy is an emerging technology which uses patients' innate immune systems. In immunotherapy, immune cells are stimulated through antibodies, the other immune cells and genetic modifications for the purposes of, for instance, cancer therapy. In this study, tumor-derived re-assembled exosome (R-Exo) was simultaneously utilized as both a drug delivery carrier and an immunostimulatory agent. A chlorin e6 photosensitizer was loaded into tumor-derived exosomes during exosomal re-assembly. After this modification, R-Exo retains its original average size and has the same membrane proteins, which allows for targeting of tumor cells. Chlorin e6-loaded R-Exo (Ce6-R-Exo) can be visualized by photoacoustic imaging and can efficiently generate reactive oxygen species inside tumor cells under laser irradiation. In addition, Ce6-R-Exo increased the release of cytokines from immune cells, which indicates that these modified exosomes can be used as an immunotherapeutic agent. In conclusion, we developed a novel strategy that enables photoacoustic imaging-guided photodynamic and immune-combination therapy for the treatment of cancer with tumor-derived Ce6-R-Exo.

Stability of Engineered Micro or Nanobubbles for Biomedical Applications.

A micro/nanobubble (MNB) refers to a bubble structure sized in a micrometer or nanometer scale, in which the core is separated from the external environment and is normally made of gas. Recently, it has been confirmed that MNBs can be widely used in angiography, drug delivery, and treatment. Thus, MNBs are attracting attention as they are capable of constructing a new contrast agent or drug delivery system. Additionally, in order to effectively use an MNB, the method of securing its stability is also being studied. This review highlights the factors affecting the stability of an MNB and the stability of the MNB within the ultrasonic field. It also discusses the relationship between the stability of the bubble and its applicability in vivo.

Self-Assembling ß-Glucan Nanomedicine for the Delivery of siRNA.

We aimed to design and manufacture a transporter capable of delivering small interfering RNAs (siRNAs) into the skin without causing any damage. ß-glucans are unique chiral polysaccharides with well-defined immunological properties and supramolecular wrapping ability. However, the chiral properties of these polymers have hardly been applied in drug delivery systems. In this study, ß-glucan nanoparticles were designed and manufactured to deliver genetic material to the target cells. The ß-glucan molecules were self-assembled with an siRNA into nanoparticles of 300-400 nm in diameter via a conformational transition process, in order to construct a gene delivery system. The assembled gene nanocarriers were associated with high gene-loading ability. The expression and efficiency of siRNA were verified after its delivery via ß-glucan. Our results provide evidence that ß-glucan nanoparticles can be effectively used to deliver siRNA into the cells.

Study and Evaluation of the Potential of Lipid Nanocarriers for Transdermal Delivery of siRNA.

The topical delivery of siRNA-based therapies has opened new avenues for the treatment of skin disorders. The use of siRNA as a therapeutic, however, is limited due to its rapid degradation and poor cellular uptake. Furthermore, the top layer of skin, the stratum corneum, is a major barrier to the delivery of topical agents. There is an unmet need for efficient topical formulations for delivering siRNA to the site of action. In this study, 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or lipofectamine is used to prepare a nanocarrier for delivering siRNA against glyceraldehyde 3-phosphate dehydrogenase (GAPDH); GAPDH expression is then evaluated at the cellular level. In addition, a dermal transport assay is designed and implemented to evaluate the penetration and delivery efficacy of siRNA in pig skin using lipid nanocarriers. The delivery of siRNA with the use of a lipid nanocarrier is significantly better than the delivery of siRNA without it. Thus, the findings identify lipid nanocarriers as excellent candidates for the transdermal delivery of siRNA for gene silencing in the skin and thus for applications in related preclinical models.

Effective delivery of mycophenolic acid by oxygen nanobubbles for modulating immunosuppression.

Immunosuppressive drugs are crucial for preventing acute graft rejection or autoimmune diseases. They are generally small molecules that require suitable drug carriers for ensuring stability, bioavailability, and longer half-life. Mycophenolic acid (MPA) is an extensively studied immunosuppressive drug. However, it requires suitable carriers for overcoming clinical limitations. Currently, lipid-shelled micro- and nanobubbles are being thoroughly investigated for diagnostic and therapeutic applications, as they possess essential properties, such as injectability, smaller size, gaseous core, high surface area, higher drug payload, and enhanced cellular penetration. Phospholipids are biocompatible and biodegradable molecules, and can be functionalized according to specific requirements. Methods: In this study, we synthesized oxygen nanobubbles (ONBs) and loaded the hydrophobic MPA within the ONBs to generate ONB/MPA. Peripheral blood mononuclear cells (PBMCs) were treated with ONB/MPA to determine the suppression of immune response by measuring cytokine release. In vivo murine experiments were performed to evaluate the effectiveness of ONB/MPA in the presence of inflammatory stimulants. Results: Our results suggest that ONBs successfully delivered MPA and reduced the release of cytokines, thereby controlling inflammation and significantly increasing the survival rate of animals. Conclusion: This method can be potentially used for implantation and for treating autoimmune diseases, wherein immunosuppression is desired.

NIR Laser-Responsive PNIPAM and Gold Nanorod Composites for the Engineering of Thermally Reactive Drug Delivery Nanomedicine.

When ingesting a drug on its own or injecting it directly into tissue, its concentration increases immediately within the body, which often exacerbates the side effects and increases its toxicity. To solve this problem, we synthesized the thermally reactive polymer poly(N-isopropylacrylamide) (PNIPAM) using reversible addition-fragmentation chain transfer (RAFT) polymerization and prepared nanocarriers by binding PNIPAM to gold nanorods (GRs), with the anticancer agent doxorubicin (DOX) used as a model drug. PNIPAM changes from hydrophilic to hydrophobic at temperatures above its lower critical solution temperature, which represents a coil-to-globule volume phase transition. Because GRs absorb near-infrared (NIR) laser light and emit energy, PNIPAM aggregation occurs when the synthesized PNIPAM/GR are subjected to an NIR laser, and the temperature of the GRs rises. Using this principle, DOX was combined with the PNIPAM/GR complex, and the resulting anticancer effects with and without laser treatment were observed in Hela and MDA-MB-231 cells. In our proposed complex, the GR binding rate of PNIPAM reached 20% and the DOX binding rate reached 15%. The release profile of the drug following laser irradiation was determined using a drug release test and confocal microscopy imaging. It was subsequently confirmed that the release of the drug is higher at higher temperatures, especially with laser treatment. The proposed combination of temperature-reactive polymers and gold nanostructures shows promise for future research into controlled drug release.

Effective Delivery of Anti-Cancer Drug Molecules with Shape Transforming Liquid Metal Particles.

Liquid metals are being studied intensively because of their potential as a drug delivery system. Eutectic gallium-indium (EGaIn) alloy liquid metals have a low melting point, low toxicity, and excellent tissue permeability. These properties may enable them to be vascular embolic agents that can be deformed by light or heat. In this study, we developed EGaIn particles that can deliver anticancer drugs to tumor cells in vitro and change their shapes in response to external stimuli. These particles were prepared by sonicating a solution containing EGaIn and amphiphilic lipids. The liquid metal (LM)/amphiphilic lipid (DSPC, 1,2-distearoyl-sn-glycero-3-phosphocholin) particles formed a vehicle for doxorubicin, an anticancer drug, which was released (up to 50%) when the shape of the particles was deformed by light or heat treatment. LM/DSPC particles are non-toxic and LM/DSPC/doxorubicin particles have anticancer effects (resulting in a cell viability of less than 50%). LM/DSPC/doxorubicin particles were also able to mimic blood vessel embolisms by modifying their shape using precisely controlled light and heat in engineered microchannels. The purpose of this study was to examine the potential of EGaIn materials to treat tumor tissues that cannot be removed by surgery.

Association of novel domain in active site of archaic hyperthermophilic maltogenic amylase from Staphylothermus marinus.

Staphylothermus marinus maltogenic amylase (SMMA) is a novel extreme thermophile maltogenic amylase with an optimal temperature of 100 °C, which hydrolyzes α-(1-4)-glycosyl linkages in cyclodextrins and in linear malto-oligosaccharides. This enzyme has a long N-terminal extension that is conserved among archaic hyperthermophilic amylases but is not found in other hydrolyzing enzymes from the glycoside hydrolase 13 family. The SMMA crystal structure revealed that the N-terminal extension forms an N' domain that is similar to carbohydrate-binding module 48, with the strand-loop-strand region forming a part of the substrate binding pocket with several aromatic residues, including Phe-95, Phe-96, and Tyr-99. A structural comparison with conventional cyclodextrin-hydrolyzing enzymes revealed a striking resemblance between the SMMA N' domain position and the dimeric N domain position in bacterial enzymes. This result suggests that extremophilic archaea that live at high temperatures may have adopted a novel domain arrangement that combines all of the substrate binding components within a monomeric subunit. The SMMA structure provides a molecular basis for the functional properties that are unique to hyperthermophile maltogenic amylases from archaea and that distinguish SMMA from moderate thermophilic or mesophilic bacterial enzymes.