Photoechogenic Inflatable Nanohybrids for Upconversion-Mediated Sonotheranostics.

Hybrid nanostructures are promising for ultrasound-triggered drug delivery and treatment, called sonotheranostics. Structures based on plasmonic nanoparticles for photothermal-induced microbubble inflation for ultrasound imaging exist. However, they have limited therapeutic applications because of short microbubble lifetimes and limited contrast. Photochemistry-based sonotheranostics is an attractive alternative, but building near-infrared (NIR)-responsive echogenic nanostructures for deep tissue applications is challenging because photolysis requires high-energy (UV-visible) photons. Here, we report a photochemistry-based echogenic nanoparticle for in situ NIR-controlled ultrasound imaging and ultrasound-mediated drug delivery. Our nanoparticle has an upconversion nanoparticle core and an organic shell carrying gas generator molecules and drugs. The core converts low-energy NIR photons into ultraviolet emission for photolysis of the gas generator. Carbon dioxide gases generated in the tumor-penetrated nanoparticle inflate into microbubbles for sonotheranostics. Using different NIR laser power allows dual-modal upconversion luminescence planar imaging and cross-sectional ultrasonography. Low-frequency (10 MHz) ultrasound stimulated microbubble collapse, releasing drugs deep inside the tumor through cavitation-induced transport. We believe that the photoechogenic inflatable hierarchical nanostructure approach introduced here can have broad applications for image-guided multimodal theranostics.

Synthesis of PEG-dendron for surface modification of pancreatic islets and suppression of the immune response.

Islet cell transplantation has been an effective method for the treatment of type 1 diabetes. The transplanted islets release insulin in response to changes in blood glucose levels. The clinical application of islet transplantation, however, has been hindered because of some critical problems including immune responses to grafted islets and side effects caused by overdosed immunosuppressive drugs. Herein, surface modification technology using poly(ethylene glycol) (PEG)-dendron was proposed to safeguard islets from the host immune system. PEG-dendron was synthesized by a divergent polymerization method and utilized to cover the islet antigen surface. Successful conjugation of PEG-dendron on the islet surface was achieved without affecting islet morphology, viability, and functionality at a concentration of 1.00%. Surface modification using PEG-dendron effectively prevented protein absorption and immune activation. Foremost, it improved the survival rate of islet grafts in vivo when combined with a low dose of immunosuppressive drugs. In conclusion, PEG-dendron is a potential candidate for the surface modification of pancreatic islets to mitigate immune responses after transplantation.

Size-engineered biocompatible polymeric nanophotosensitizer for locoregional photodynamic therapy of cancer.

Current approaches in use of water-insoluble photosensitizers for photodynamic therapy (PDT) of cancer often demand a nano-delivery system. Here, we report a photosensitizer-loaded biocompatible nano-delivery formulation (PPaN-20) whose size was engineered to ca. 20nm to offer improved cell/tissue penetration and efficient generation of cytotoxic singlet oxygen. PPaN-20 was fabricated through the physical assembly of all biocompatible constituents: pyropheophorbide-a (PPa, water-insoluble photosensitizer), polycaprolactone (PCL, hydrophobic/biodegradable polymer), and Pluronic F-68 (clinically approved polymeric surfactant). Repeated microemulsification/evaporation method resulted in a fine colloidal dispersion of PPaN-20 in water, where the particulate PCL matrix containing well-dispersed PPa molecules inside was stabilized by the Pluronic corona. Compared to a control sample of large-sized nanoparticles (PPaN-200) prepared by a conventional solvent displacement method, PPaN-20 revealed optimal singlet oxygen generation and efficient cellular uptake by virtue of the suitably engineered size and constitution, leading to high in vitro phototoxicity against cancer cells. Upon administration to tumor-bearing mice by peritumoral route, PPaN-20 showed efficient tumor accumulation by the enhanced cell/tissue penetration evidenced by in vivo near-infrared fluorescence imaging. The in vivo PDT treatment with peritumorally administrated PPaN-20 showed significantly enhanced suppression of tumor growth compared to the control group, demonstrating great potential as a biocompatible photosensitizing agent for locoregional PDT treatment of cancer.

Amphiphilized poly(ethyleneimine) nanoparticles: a versatile multi-cargo carrier with enhanced tumor-homing efficiency and biocompatibility.

Current theranostic approaches in cancer therapy demand delivery systems that can carry multiple drugs or imaging agents in a single nanoplatform with uniform biodistribution and improved target specificity. In this study, we have developed amphiphilized poly(ethyleneimine) nanoparticles (aPEI NPs) as a versatile multi-cargo delivery platform. The aPEI NPs were engineered to have the loading capacity for both hydrophobic molecules and negatively charged hydrophilic colloidal cargos through amphiphilic modification, i.e., octadecylation and subsequent PEGylation of poly(ethyleneimine). In the aqueous phase, the resulting aPEIs underwent amphiphilic self-assembly into spherical nanoparticles whose structure is constituted of the hydrophobic core with the positively charged surface and the hydrophilic neutral corona. The high degree of PEGylation resulted in the tiny colloidal size (<15 nm in diameter) and rendered the outmost surface coated with an antifouling corona which minimizes general shortcomings of poly(ethyleneimine)-based nanocarriers (e.g., cytotoxicity and liver filtration) while keeping its advantage (loading capability for negatively charged drugs). The unique nanostructure of aPEI NPs allowed for facile loading of hydrophobic model drugs (rubrene and IR780) in the core as well as negatively charged colloids (Pdots, proteins and DNA) on the inner surface via the hydrophobic and electrostatic interactions, respectively. Fluorescence imaging experiments demonstrated that the highly PEGylated aPEI-25 NPs showed prolonged blood circulation with minimal liver filtration and efficient delivery of the loaded cargos to the tumor. These combined merits, along with negligible toxicity profiles both in vitro and in vivo, validate the potential of aPEI-25 NPs as versatile nanocarriers for multi-cargo delivery.

Conjugated polymer/photochromophore binary nanococktails: bistable photoswitching of near-infrared fluorescence for in vivo imaging.

Nanoscopic dense integration between solid-state emission and photochromism provides nanoprobes capable of photoswitching of bright NIR fluorescence with high on/off contrast, bistability and improved signal identification, being suitable for imaging applications in autofluorescence-rich in vivo environments.

Poly(oxyethylene sugaramide)s: unprecedented multihydroxyl building blocks for tumor-homing nanoassembly.

Hydrogen bonding is a major intermolecular interaction for self-assembly occurring in nature. Here we report novel polymeric carbohydrates, i.e., poly(oxyethylene galactaramide)s (PEGAs), as biomimetic building blocks to construct hydrogen bond-mediated self-assembled nanoparticles that are useful for biomedical in vivo applications. PEGAs were conceptually designed as a biocompatible hybrid between polysaccharide and poly(ethylene glycol) (PEG) to attain multivalent hydrogen bonding as well as fully hydrophilic, non-ionic and antifouling characteristics. It was revealed that PEGAs are capable of homospecies hydrogen bonding in water and constructing multi-chain assembled nanoparticles whose structural integrity is highly stable with varying concentration, temperature and pH. Using near-infrared fluorescence imaging we demonstrate facile blood circulation and efficient tumor accumulation of the self-assembled PEGA nanoparticles that were intravenously injected into mice. These in vivo behaviors elucidate the combined merits of our design strategy, i.e., biocompatible chemical constitution capable of multivalent hydrogen bonding, antifouling properties, minimal cell interaction and mesoscopic colloidal self-assembly, as well as size-motivated tumor targeting.

Phthalocyanine-aggregated polymeric nanoparticles as tumor-homing near-infrared absorbers for photothermal therapy of cancer.

Phthalocyanine-aggregated Pluronic nanoparticles were constructed as a novel type of near-infrared (NIR) absorber for photothermal therapy. Tiny nanoparticles (~ 60 nm, FPc NPs) were prepared by aqueous dispersion of phthalocyanine-aggregated self-assembled nanodomains that were phase-separated from the melt mixture with Pluronic. Under NIR laser irradiation, FPc NPs manifested robust heat generation capability, superior to an individual cyanine dye and cyanine-aggregated nanoparticles. Micro- and macroscopic imaging experiments showed that FPc NPs are capable of internalization into live cancer cells as well as tumor accumulation when intravenously administered into living mice. It is shown here that continuous NIR irradiation of the tumor-targeted FPc NPs can cause phototherapeutic effects in vitro and in vivo through excessive local heating, demonstrating potential of phthalocyanine-aggregated nanoparticles as an all-organic NIR nanoabsorber for hyperthermia.

Dye/peroxalate aggregated nanoparticles with enhanced and tunable chemiluminescence for biomedical imaging of hydrogen peroxide.

Hydrogen peroxide (H(2)O(2)) is an endogenous molecule that plays diverse physiological and pathological roles in living systems. Here we report multimolecule integrated nanoprobes with the enhanced chemiluminescence (CL) response to H(2)O(2) that is produced in cells and in vivo. This approach is based on the nanoscopic coaggregation of a dye exhibiting aggregation-enhanced fluorescence (AEF) with a H(2)O(2)-responsive peroxalate that can convert chemical reaction energy into electronic excitation. The coaggregated CL nanoparticles (FPOA NPs) with an average size of ~20 nm were formulated by aqueous self-assembly of a ternary mixture of a surfactant (Pluronic F-127) and concentrated hydrophobic dye/peroxalte payloads. Spectroscopic studies manifest that FPOA NPs as a reagent-concentrated nanoreactor possess the signal enhancement effect by AEF, as well as the optimized efficiencies for H(2)O(2) peroxalate reaction and subsequent intraparticle energy transfer to the dye aggregates, to yield greatly enhanced CL generation with a prolonged lifetime. It is shown that the enhanced CL signal thereby is capable of detecting intracellular H(2)O(2) overproduced during immune response. We also demonstrate that the densely integrated nature of FPOA NPs facilitates further intraparticle CL energy transfer to a low-energy dopant to red shift the spectrum toward the biologically more transparent optical window, which enables the high-sensitivity in vivo visualization of H(2)O(2) associated with early stage inflammation.

Covalent decoration of graphene oxide with dendrimer-encapsulated nanoparticles for universal attachment of multiple nanoparticles on chemically converted graphene.

We report a method for universal assembly of multiple nanoparticles with different sizes and compositions on a single chemically converted graphene sheet with good control over particle sizes in the range of 1 to 2 nm through the covalent immobilization of dendrimer-encapsulated nanoparticles.

In vivo evaluation of oral anti-tumoral effect of 3,4-dihydroquinazoline derivative on solid tumor.

An extension of our previously reported 3,4-dihydroquinazoline derivative is investigated. Oral anti-tumoral activity of 3,4-dihydroquinazoline derivative (KYS05090) as potent and selective T-type calcium channel blocker was in vivo evaluated against A549 xenograft in BALB/c(nu/nu) nude mice. The rate of tumor volume increment in mouse model with KYS05090-treated group was remarkably slower than that of control group. With respect to tumor weight, it exhibited 60% and 67% tumor growth inhibition through oral administration of 1 and 5mg/kg of bodyweight, respectively, compared to control and was more potent than paclitaxel (53%). In addition, KYS05090 (10 and 50mg/kg, po) was found to have a marked analgesic effect in acetic acid-induced writhing test, whereas it did not show any effect on hot plate test.

Rhodamine-based chemosensing monolayers on glass as a facile fluorescent "turn-on" sensing film for selective detection of Pb2+.

Rhodamine-based chemosensors 1 and 2 were synthesized and self-assembled onto glass surfaces for the selective fluorescent sensing of Pb(2+). The immobilized chemosensors showed fluorescent responses that were turned-on with Pb(2+) in CH(3)CN, selectively over various metal ions. The Pb(2+)-selective fluorescent switch of the immobilized chemosensors was also reversible, allowing for repeated use for Pb(2+) detection.

Heavy-atomic construction of photosensitizer nanoparticles for enhanced photodynamic therapy of cancer.

A new type of heavy-atom-affected Pluronic (F-127) nanoparticle (FIC NP) for photodynamic therapy (PDT) is reported. FIC NPs are formulated with biocompatible constituents, and contain densely integrated iodinated aromatic molecules that form a structurally rigid core matrix and stably encapsulate photosensitizers in a monomeric form. Tiny nanoparticles (≈10 nm) are prepared by aqueous dispersion of photosensitizer-embedded aromatic nanodomains, which self-assemble by phase separation from the Pluronic melt mixture. By using spectroscopic studies and cellular experiments, the following is demonstrated: 1) enhanced singlet-oxygen generation by means of the intraparticle heavy-atom effect on the embedded photosensitizer, 2) facilitated cell uptake due to the small nanoscopic size as well as the Pluronic surface characteristics, and thereby 3) actual enhancement of PDT efficacy for a human breast-cancer cell line (MDA-MB-231), which validates a photophysically motivated nanoformulation approach toward an advanced photosensitizing nanomedicine.

Antitumor activity of 3,4-dihydroquinazoline dihydrochloride in A549 xenograft nude mice.

In the previous article we have reported that 3,4-dihydroquinazoline 1 is a potent and selective T-type calcium channel blocker that exhibited strong anti-cancer activity in vitro. Compound 1·2HCl was further in vivo evaluated against A549 xenograft in BALB/c nude mice, which exhibited 49% tumor-weight inhibition through intravenous administration of 2 mg/kg of body weight and was more potent than doxorubicin. Moreover, compound 1·2HCl has an oral bioavailability of 98% with LD(50) values of 693 mg/kg (p.o. route) and 40.0 mg/kg (i.v. route) of body weight. In addition, its efficient scale-up synthetic method was developed.

Multifunctional doxorubicin loaded superparamagnetic iron oxide nanoparticles for chemotherapy and magnetic resonance imaging in liver cancer.

To develop a drug delivery system with enhanced efficacy and minimized adverse effects, we synthesized a novel polymeric nanoparticles, (YCC-DOX) composed of poly (ethylene oxide)-trimellitic anhydride chloride-folate (PEO-TMA-FA), doxorubicin (DOX) and superparamagnetic iron oxide (Fe(3)O(4)) and folate. The efficacy of the nanoparticles was evaluated in rats and rabbits with liver cancer, in comparison with free-DOX (FD) and a commercial liposome drug, DOXIL. YCC-DOX showed the anticancer efficacy and specifically targeted folate receptor (FR)-expressing tumors, thereby increasing the bioavailability and efficacy of DOX. The relative tumor volume of the YCC-DOX group was decreased two- and four-fold compared with the FD and DOXIL groups in the rat and rabbit models, respectively. Furthermore, YCC-DOX showed higher MRI sensitivity comparable to a conventional MRI contrast agent (Resovist), even in its lower iron content. In the immunohistochemical analysis, YCC-DOX group showed the lower expression of CD34 and Ki-67, markers of angiogenesis and cell proliferation, respectively, while apoptotic cells were significantly rich in the YCC-DOX group in terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. These results indicate that YCC-DOX is a promising candidate for treating liver cancer and monitoring the progress of the cancer using MRI.

Synthesis and PGE(2) production inhibition of 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione derivatives.

3,4-Diphenyl-substituted 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione derivatives were synthesized and evaluated for the inhibitory activities on LPS-induced PGE(2) production in RAW 264.7 macrophage cells. Both 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione rings as main scaffolds were easily obtained using one of three synthetic methods. Among the compounds investigated, 1H-3-(4-sulfamoylphenyl)-4-phenyl-pyrrole-2,5-dione (6l) showed a strong inhibitory activity (IC(50)=0.61microM) of PGE(2) production.

3D QSAR studies on 3,4-dihydroquinazolines as T-type calcium channel blocker by comparative molecular similarity indices analysis (CoMSIA).

A comparative molecular similarity indices analysis (CoMSIA) of a set of 42 3,4-dihydroquinazolines have been performed to find out the pharmacophore elements for T-type calcium channel blocking activity. The most potent compound, 33 (KYS05090) was used to align the molecules. As a result, we obtained 3D QSAR model which provided good predictivity for the training set (q(2)=0.642, r(2)=0.874) and the test set (r(pred)(2)=0.884). This model would guide the design of new chemical entities potentially having high potency.

Total synthesis and biological evaluation of methylgerambullone.

First total synthesis of methylgerambullone (MGB, 1) isolated from Glycosmis angustifolia was completed via a convergent route. The effect of MGB on the contractile responses of the isolated guinea-pig ileum induced by acetylcholine was investigated. As a result, it showed a potent relaxation rate (78.66+/-4.30% at 100mg/L) in a concentration-dependent manner on longitudinal smooth muscle contraction of isolated guinea-pig ileum induced by 1microM acetylcholine.

Synthesis and SAR study of T-type calcium channel blockers. Part II.

3,4-Dihydroquinazoline derivatives have been known to be the novel and potent T-type calcium channel blockers. From a systematic variation of 3,4-dihydroquinazoline derivative 5c (KYS05043), plausible SAR results were established. It was revealed that a 5-(dimethylamino)pentylamino group at R(1), a biphenyl group at R(2), and a benzyl amido group at R(3)in the 3,4-dihydroquinazoline backbone are closely related with the channel selectivity (T/N-type) as well as the potency based on the discovery of 6k (KYS05090).

T-type Ca2+ channel blockers suppress the growth of human cancer cells.

In order to further clarify the role of T-type Ca(2+) channels in cell proliferation, we have measured the growth inhibition of human cancer cells by using our potent T-type Ca(2+) channel blockers. As a result, KYS05090, a most potent T-type Ca(2+) channel blocker, was found to be as potent as doxorubicin against some human cancer cells without acute toxicity. Therefore, this letter provides the biological results that T-type calcium channel is important in regulating the important cellular phenotype transition leading to cell proliferation, and thus novel T-type Ca(2+) channel blocker presents new prospects for cancer treatment.

Discovery of potent T-type calcium channel blocker.

The intensive SAR study of 3,4-dihydroquinazoline series led to the most potent compound 10 (KYS05090: IC(50)=41+/-1 nM) against T-type calcium channel and its potency is nearly comparable to that of Kurtoxin. As a small organic molecule, this compound showed the highest blocking activity reported to date.