Controllable CO Release Following Near-Infrared Light-Induced Cleavage of Iron Carbonyl Derivatized Prussian Blue Nanoparticles for CO-Assisted Synergistic Treatment

Carbon monoxide (CO) causes the dysfunction of mitochondria to induce the apoptosis of cancer cells giving a promising choice as an emerging treatment. The currently reported CO-based complexes still suffer from many limitations. Synthesis of CO-release carriers in the manner of on-demand control is highly anticipated. In this study, we present a near-infrared (NIR) light-responsive CO-delivery nanocarrier, a PEGylated iron carbonyl derivatized Prussian blue (PB) nanoparticle (NP). Taking the structural characteristic containing Fe³⁺-N≡C-Fe²⁺ unit, the -CN^- served as the active sites for the coordination of iron carbonyl, while the surface Fe sites chelated with the amine-functionalized polyethylene glycol (NH₂-PEG₆₀₀₀-NH₂) to yield PEGylated PB NPs carrying CO. The control of light intensity and exposure period is important to release the amount of CO as well as to deliver the hyperthermia effect. The combination therapy including CO and photothermal treatments displayed a synergistic effect against cancer cells. Importantly, the release of CO is inert in the blood circulation without NIR irradiation. The blood oxygen saturation measured by the pulse oximeter and the HCO₃, tCO₂, and pH values analyzed by the blood assay revealed the steady status from the mice studies, showing no acute CO poisoning.

Controllable NO release from Cu1.6S nanoparticle decomposition of S-nitrosoglutathiones following photothermal disintegration of polymersomes to elicit cerebral vasodilatory activity

Since the discovery of nitric oxide (NO) as a vasodilator, numerous NO therapies have been attempted to remedy disorders related to pathological vasoconstriction such as coronary artery disease. Despite the advances, clinical applications of NO therapies remain limited mainly because of the low stability of molecular NO donors (and NO molecules), and concerns about the increased oxidative stress and reduced arterial pressure associated with the systemic administration of NO. Here we design a photo-responsive polymersome with nitrosothiols and Cu_1.6S nanoparticles in its core and shell, respectively, and demonstrate the photo-triggered release of NO and its vasodilatory activity on zebrafish. Unlike conventional approaches, our design enhances the stability of NO donors and prospectively enables spatiotemporal regulation of NO release, thus minimizing the harmful effects associated with conventional NO therapies. We anticipate that such a strategy will open up new clinical applications of NO and help reveal the complex biological effects of NO in vivo.

Fabrication of Silica-Coated Hollow Carbon Nanospheres Encapsulating Fe3O4 Cluster for Magnetical and MR Imaging Guided NIR Light Triggering Hyperthermia and Ultrasound Imaging

Iron oxide nanoparticles (IONPs)-carbon (C) hybrid zero-dimensional nanostructures normally can be categorized into core-shell and yolk-shell architectures. Although IONP-C is a promising theranostic nanoagent, the in vivo study has surprisingly been less described. In addition, little effort has strived toward the fabrication of yolk-shell compared to the core-shell structures. In this context, we synthesized a yolk-shell type of the silica-coated hollow carbon nanospheres encapsulating IONPs cluster, which can be dispersed in aqueous solution for systemic studies in vivo, via the preparation involving the mixed micellization, polymerization/hollowing, sol-gel (hydration-condensation), and pyrolysis processes. Through a surface modification of the polyethylenimine followed by the sol-gel process, the silica shell coating was able to escape from condensing and sintering courses resulting in aggregation, due to the annealing. Not limited to the well-known functionalities in magnetical targeting and magnetic resonance (MR) imaging for IONP-C hybrid structures, we expanded this yolk-shell NPs as a near-infrared (NIR) light-responsive echogenic nanoagent giving an enhanced ultrasound imaging. Overall, we fabricated the NIR sensitive yolk-shell IONP-C to activate ultrasound imaging and photothermal ablation under magnetically and MR imaging guided therapy.

Bacteria-Mediated Hypoxia-Specific Delivery of Nanoparticles for Tumors Imaging and Therapy

The hypoxia region in a solid tumor has been recognized as a complex microenvironment revealing very low oxygen concentration and deficient nutrients. The hypoxic environment reduces the susceptibility of the cancer cells to anticancer drugs, low response of free radicals, and less proliferation of cancer cells in the center of the solid tumors. However, the reduced oxygen surroundings provide an appreciable habitat for anaerobic bacteria to colonize. Here, we present the bacteria-mediated targeting hypoxia to offer the expandable spectra for diagnosis and therapy in cancer diseases. Two delivery approaches involving a cargo-carrying method and an antibody-directed method were designed to deliver upconversion nanorods for imaging and Au nanorods for photothermal ablation upon near-infrared light excitation for two forms of the anaerobic Bifidobacterium breve and Clostridium difficile. The antibody-directed strategy shows the most effective treatment giving stronger imaging and longer retention period and effective therapy to completely remove tumors.

Ultrasound-Induced Reactive Oxygen Species Mediated Therapy and Imaging Using a Fenton Reaction Activable Polymersome

Ultrasound techniques have been extensively employed for diagnostic purposes. Because of its features of low cost, easy access, and noninvasive real-time imaging, toward clinical practice it is highly anticipated to simply use diagnostic ultrasound to concurrently perform imaging and therapy. We report a H2O2-filled polymersome to display echogenic reflectivity and reactive oxygen species-mediated cancer therapy simply triggered by the microultrasound diagnostic system accompanied by MR imaging. Instead of filling common perfluorocarbons, the encapsulation of H2O2 in H2O2/Fe3O4-PLGA polymersome provides O2 as the echogenic source and (•)OH as the therapeutic element. On exposure to ultrasound, the polymersome can be easily disrupted to yield (•)OH through the Fenton reaction by reaction of H2O2 and Fe3O4. We showed that malignant tumors can be completely removed in a nonthermal process.

Syntheses of Platinum-Sulindac Complexes and Their Nanoparticles as Targeted Anticancer Drugs

Platinum(II)-sulindac complexes [{η² -C₅ H₄ SN(O)}Pt(DMSO){O(C=O)Sulindac}], [{η² -C₅ H₄ SN(O)}PtCl{(S=O)Sulindac}], [{η² -C₅ H₄ SN(O)}PtCl{(S=O)Sulindac-succinimide}], and [{η² -C₅ H₄ SN(O)}PtCl{(S=O)Sulindac-thymidine}] were synthesized that exhibited IC₅₀ values of 2.9-4.8 μm against human oral cancer cells OECM1. The poly(lactic-co-glycolic acid) (PLGA) encapsulated [{η² -C₅ H₄ SN(O)}PtCl{(S=O)Sulindac}] also showed cytotoxic activity although less potent than the pristine species.

Gold over Branched Palladium Nanostructures for Photothermal Cancer Therapy

Bimetallic nanostructures show exciting potential as materials for effective photothermal hyperthermia therapy. We report the seed-mediated synthesis of palladium-gold (Pd-Au) nanostructures containing multiple gold nanocrystals on highly branched palladium seeds. The nanostructures were synthesized via the addition of a gold precursor to a palladium seed solution in the presence of oleylamine, which acts as both a reducing and a stabilizing agent. The interaction and the electronic coupling between gold nanocrystals and between palladium and gold broadened and red-shifted the localized surface plasmon resonance absorption maximum of the gold nanocrystals into the near-infrared region, to give enhanced suitability for photothermal hyperthermia therapy. Pd-Au heterostructures irradiated with an 808 nm laser light caused destruction of HeLa cancer cells in vitro, as well as complete destruction of tumor xenographs in mouse models in vivo for effective photothermal hyperthermia.

Charge collection enhancement by incorporation of gold-silica core-shell nanoparticles into P3HT:PCBM/ZnO nanorod array hybrid solar cells

In this work, gold-silica core-shell (Au@silica) nanoparticles (NPs) with various silica-shell thicknesses are incorporated into P3HT:PCBM/ZnO nanorod (NR) hybrid solar cells. Enhancement in the short-circuit current density and the efficiency of the hybrid solar cells is attained with the appropriate addition of Au@silica NPs regardless of the silica-shell thickness. Compared to the P3HT:PCBM/ZnO NR hybrid solar cell, a 63% enhancement in the efficiency is achieved by the P3HT:PCBM/Au@silica NP/ZnO NR hybrid solar cell. The finite difference time domain simulations indicate that the strength of the Fano resonance, i.e., the electric field of the quasi-static asymmetric quadrupole, on the surface of Au@silica NPs in the P3HT:PCBM/ZnO NR hybrid significantly decreases with increasing thickness of the silica shell. Raman characterization reveals that the degree of P3HT order increases when Au@silica NPs are incorporated into the P3HT:PCBM/ZnO NR hybrid. The charge separation at the interface between P3HT and PCBM as well as the electron transport in the active layer are retarded by the electric field of the Fano resonance. Nevertheless, the prolongation of the electron lifetime and the reduction of the electron transit time in the P3HT:PCBM/ZnO NR hybrid solar cells, which result in an enhancement of electron collection, are achieved by the addition of Au@silica NPs. This may be attributed to the improvement in the degree of P3HT order and connectivity of PCBM when Au@silica NPs are incorporated into the P3HT:PCBM active layer.

Antimicrobial applications of water-dispersible magnetic nanoparticles in biomedicine

The increasing morbidity and mortality of infectious diseases is an increasing concern. Despite the continuous development and synthesis of new antimicrobial drugs, microbial pathogens are exhibiting increased multi-drug resistance. Nanomaterials display unique and well-defined physical and chemical properties including a very high surface area to volume ratio, and new approaches for antimicrobial therapies have attempted to combine nanomaterials and current antimicrobial drugs. Magnetic nanoparticles (MNPs) are characterized by biocompatibility, biodegradation, and safety for human ingestion. Iron oxide nanoparticles have been approved for human use by the US Food and Drug Administration (FDA). For biomedicine applications, MNPs require surface modification to become water-soluble and be stable enough to resist the effects of proteins and salts in the physiological environment. MNPs can combine various substrata, such as biomolecules and nanomaterials to generate new antimicrobial agents which combine antibacterial, antiviral, and antifungal properties. This can be accomplished through a series of surface modification methods. Because MNPs have unique superparamagnetic characteristics, they can be controlled and recycled by an external magnetic field.In addition, the antimicrobial activity of MNPs-based nanocomposites is superior to that of metallic nanoparticles. This paper reviews the recent literature on the use of MNP-based nanomaterials in antimicrobial applications in biomedicine. Antimicrobial applications mainly focus on inhibiting and killing bacteria and fungi and viruses inactivation. The synthesis, surface modification, and characteristics related to MNPs will also be briefly addressed.

P3HT-based nanoarchitectural Fano solar cells

The finite difference time domain simulation shows the existence of an asymmetric quadrupole of Fano resonance on the surface of a gold-silica core-shell (Au@silica) nanoparticle (NP) as being incorporated into the metal oxide nanoarchitecture/P3HT hybrid. Compared to the metal oxide nanoarchitecture/P3HT hybrid solar cell, a 30% enrichment of the short-circuit current density (Jsc) is attained in the P3HT-based nanoarchitectural Fano solar cell with the Au@silica NPs. The enhancement of charge separation in the cell by the electric field of the Fano resonance is directly evidenced by time-resolved photoluminescence measurements. The increase of the degree of P3HT order in the hybrid by the incorporation of Au@silica NPs into the hybrid active layer may also contribute to the enhancement in the Jsc. Charge carrier dynamic measurements show that an electron collection efficiency of ∼97% can be maintained in the P3HT-based nanoarchitectural Fano solar cell. Significant improvement of the efficiency of the inverted metal oxide/P3HT hybrid solar cell is therefore achieved.

Formation of oligonucleotide-gated silica shell-coated Fe₃O₄-Au core-shell nanotrisoctahedra for magnetically targeted and near-infrared light-responsive theranostic platform

A new multifunctional nanoparticle to perform a near-infrared (NIR)-responsive remote control drug release behavior was designed for applications in the biomedical field. Different from the previous studies in formation of Fe3O4-Au core-shell nanoparticles resulting in a spherical morphology, the heterostructure with polyhedral core and shell was presented with the truncated octahedral Fe3O4 nanoparticle as the core over a layer of trisoctahedral Au shell. The strategy of Fe3O4@polymer@Au was adopted using poly-l-lysine as the mediate layer, followed by the subsequent seeded growth of Au nanoparticles to form a Au trisoctahedral shell. Fe3O4@Au trisoctahedra possess high-index facets of {441}. To combine photothermal and chemotherapy in a remote-control manner, the trisoctahedral core-shell Fe3O4@Au nanoparticles were further covered with a mesoporous silica shell, yielding Fe3O4@Au@mSiO2. The bondable oligonucleotides (referred as dsDNA) were used as pore blockers of the mesoporous silica shell that allowed the controlled release, resulting in a NIR-responsive DNA-gated Fe3O4@Au@mSiO2 nanocarrier. Taking advantage of the magnetism, remotely triggered drug release was facilitated by magnetic attraction accompanied by the introduction of NIR radiation. DNA-gated Fe3O4@Au@mSiO2 serves as a drug control and release carrier that features functions of magnetic target, MRI diagnosis, and combination therapy through the manipulation of a magnet and a NIR laser. The results verified the significant therapeutic effects on tumors with the assistance of combination therapy consisting of magnetic guidance and remote NIR control.

Oligonucleotides--assembled Au nanorod-assisted cancer photothermal ablation and combination chemotherapy with targeted dual-drug delivery of Doxorubicin and Cisplatin prodrug

External stimuli responsive dual drugs carrier was synthesized with Au nanorods (NRs) as the platform. On Au NRs, single stranded DNAs were assembled using 5' thiol end. Following this, complementary DNA (cDNA) strands were hybridized. This hybridized double stranded DNA facilitated doxorubicin (Dox) intercalation into the duplexes. The cDNA designed with the 5' amine functional group assisted to tether platinum [Pt(IV)] prodrugs by establishing amide bond with the acid group at the axial ligand. The other axial acid group in Pt(IV) prodrugs was conjugated with the folic acid (FA) to target folate receptors overexpressed in the cancer cells. This targeting vehicle provided remote-controlled delivery of this high toxic cargo cocktail at the tumor site, ensuring extra specificity that can avoid acute toxicity, where release of Dox and Pt(IV) was achieved upon NIR 808 nm diode laser irradiation. The dehybridization set the Dox free to bind the cell nucleus and cellular reductants reduced Pt(IV) to yield toxic Pt(II), becoming an active drug. The in vitro and in vivo studies revealed that this external stimulus responsive combination drug delivery was significantly effective.

Near-infrared light-responsive nanomaterials in cancer therapeutics

Near-infrared light sensitive nanomaterials provide ideal nanoplatforms in site specific noninvasive cancer therapy.

Near-infrared light photocontrolled targeting, bioimaging, and chemotherapy with caged upconversion nanoparticles in vitro and in vivo

The major challenge in current chemotherapy is to increase local effective therapeutic concentration of drugs as well as to minimize toxicity and side effects for patients. The targeted delivery of drugs to their desired site of action in a controlled manner plays an essential role in the development of drug formulations. A photocage refers to a caged molecule rendered biologically inert by a photolabile protecting group. Molecules are illuminated with light to liberate the caged group and then become active forms. In this study, we formulate upconversion nanoparticles (UCNPs) as the NIR-triggered targeting and drug delivery vehicles that successfully deliver in vitro and in vivo for near-infrared light photocontrolled targeting, bioimaging, and chemotherapy. It is noted that there has been no report on the systemic administration UCNP-based drug delivery agents for evaluation of bioimaging and chemotherapy. To achieve phototargeting, the tumor-homing agent (i.e., folic acid) has been constructed as a photoresponsive molecule. For the chemotherapeutic effect, the antitumor drug doxorubicin is thiolated on the surface of UCNPs, forming a disulfide bond that can be cleaved by lysosomal enzymes within the cells. The caged UNCPs can serve as a platform for the improvement of selective targeting and possible reduction of adverse side effects from chemotherapy.

Preparation of superparamagnetic Mn(x)Fe(1-x)O nanoparticles from low-index-facet cubes to high-index-facet concave structures and their catalytic performance in aqueous solution

We report the synthesis of concave magnetic Mn(x)Fe(1-x)O nanoparticles with high-index facet structures by a thermal decomposition approach. The particle morphology varies from cubic shape under pure Ar, to star-like shapes with exposure to air during the reaction. The oxidative etching in the presence of air (O2) strongly affects the exposed facets on the surface. These concave nanoparticles are transferred from the organic phase to aqueous solution and show distinct catalytic activity toward the degradation of xylenol orange in aqueous solution.

Pronounced induction of endoplasmic reticulum stress and tumor suppression by surfactant-free poly(lactic-co-glycolic acid) nanoparticles via modulation of the PI3K signaling pathway

Background

Y294002 (LY) is a potent inhibitor of phosphatidylinositol 3-kinases (PI3Ks); however, biological applications of LY are limited by its poor solubility and pharmacokinetic profile. This study aimed at developing LY-loaded surfactant-free poly(lactic-co-glycolic acid) (PLGA) nanoparticles (SF-LY NPs) to improve the therapeutic efficacy of LY.

Materials and methods

Cellular viability was measured by MTT assay. The subcellular distribution of NPs was studied using an ultraviolet-visible spectrophotometer and confocal microscope. The expression of cell-death-associated proteins was determined using Western blotting and the in vivo activity of SF-LY NPs was tested in a xenograft animal model.

Results

SF-LY NPs enhanced the intracellular level of LY, induced sustained suppression of AKT, and induced marked cancer cell death. In addition, SF-LY NPs tended to accumulate in the endoplasmic reticulum (ER) and induce pronounced ER stress. Finally, SF-LY NPs exhibited a prominent antitumor effect in vivo.

Conclusion

The surfactant-free formulation of PLGA is critical to the promising anticancer activity of SF-LY NPs.

Au nanorod design as light-absorber in the first and second biological near-infrared windows for in vivo photothermal therapy

Photothermal cancer therapy using near-infrared (NIR) laser radiation is an emerging treatment. In the NIR region, two biological transparency windows are located in 650-950 nm (first NIR window) and 1000-1350 nm (second NIR window) with optimal tissue transmission obtained from low scattering and energy absorption, thus providing maximum radiation penetration through tissue and minimizing autofluorescence. To date, intensive effort has resulted in the generation of various methods that can be used to shift the absorbance of nanomaterials to the 650-950 nm NIR regions for studying photoinduced therapy. However, NIR light absorbers smaller than 100 nm in the second NIR region have been scant. We report that a Au nanorod (NR) can be designed with a rod-in-shell (rattle-like) structure smaller than 100 nm that is tailored to be responsive to the first and second NIR windows, in which we can perform hyperthermia-based therapy. In vitro performance clearly displays high efficacy in the NIR photothermal destruction of cancer cells, showing large cell-damaged area beyond the laser-irradiated area. This marked phenomenon has made the rod-in-shell structure a promising hyperthermia agent for the in vivo photothermal ablation of solid tumors when activated using a continuous-wave 808 m (first NIR window) or a 1064 nm (second NIR window) diode laser. We tailored the UV-vis-NIR spectrum of the rod-in-shell structure by changing the gap distance between the Au NR core and the AuAg nanoshell, to evaluate the therapeutic effect of using a 1064 nm diode laser. Regarding the first NIR window with the use of an 808 nm diode laser, rod-in-shell particles exhibit a more effective anticancer efficacy in the laser ablation of solid tumors compared to Au NRs.

Escape from the destruction of the galvanic replacement reaction for solid → hollow → solid conversion process in one pot reaction

Based on the difference in the redox potentials between two metal species, the galvanic replacement reaction is known to create an irreversible process to generate hollow nanostructures in a wide range of shapes. In the context of galvanic replacement reaction, continuing etching leads to the general collapse of the hollow structures because of the excess amount of oxidizing agent. We demonstrate the growth of solid nanostructures from a hollow frame-like architecture in the course of a galvanic replacement reaction without any morphology destruction. We report the successful composition transformation of solid Ag with a wide range of shapes, such as plate, decahedron, rod, prism, sphere, and foil, from as thin as <10 nm up to 5 μm and with an area of ∼4 mm(2), to their solid Au counterparts using straightforward chemical reactions. The successful conversion process relies on a decrease in the reduction rate of the metallic precursor to initiate dissolution of Ag in the first stage (a galvanic replacement reaction), then a subsequent backfilling of Au into the hollowed-out structures. Cetyltrimethylammonium bromide (CTAB) surfactant, a key parameter, interacts with metal salt precursor to form a complex species that retards metal reduction. In addition, we demonstrate conversion of solid nano-Ag to solid nano-Pd as well as of Cu foil (10 μm thick) to shiny Au foil.