A Regioselectively Oxidized 2D Bi/BiOx Lateral Nano-Heterostructure for Hypoxic Photodynamic Therapy.

Optoelectronic science and 2D nanomaterial technologies are currently at the forefront of multidisciplinary research and have numerous applications in electronics and photonics. The unique energy and optically induced interfacial electron transfer in these nanomaterials, enabled by their relative band alignment characteristics, can provide important therapeutic modalities for healthcare. Given that nano-heterostructures can facilitate photoinduced electron-hole separation and enhance generation of reactive oxygen species (ROS), 2D nano-heterostructure-based photosensitizers can provide a major advancement in photodynamic therapy (PDT), to overcome the current limitations in hypoxic tumor microenvironments. Herein, a bismuthene/bismuth oxide (Bi/BiOx)-based lateral nano-heterostructure synthesized using a regioselective oxidation process is introduced, which, upon irradiation at 660 nm, effectively generates 1 O2 under normoxia but produces cytotoxic •OH and H2 under hypoxia, which synergistically enhances PDT. Furthermore, this Bi/BiOx nano-heterostructure is biocompatible and biodegradable, and, with the surface molecular engineering used here, it improves tumor tissue penetration and increases cellular uptake during in vitro and in vivo experiments, yielding excellent oxygen-independent tumor ablation with 660 nm irradiation, when compared with traditional PDT agents.

Excretable, ultrasmall hexagonal NaGdF4:Yb50% nanoparticles for bimodal imaging and radiosensitization.

BACKGROUND: In this study, we report on the synthesis, imaging, and radiosensitizing properties of ultrasmall ß-NaGdF4:Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided that the nanoparticles are taken up intracellularly. RESULTS: Our ultrasmall ß-NaGdF4:Yb50% nanoparticles demonstrate improvement in T1-weighted contrast over the standard clinical MR imaging agent Gd-DTPA and similar CT signal enhancement capabilities as commercial agent iohexol. A 2 Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF4:Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF4:Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd3+ ions via ICP-MS. CONCLUSION: These biocompatible and in vivo clearable ultrasmall NaGdF4:Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.

Hybrid Curdlan Poly(γ -Glutamic Acid) Nanoassembly for Immune Modulation in Macrophage.

A nanoformulation composed of curdlan, a linear polysaccharide of 1,3-ß-linked d-glucose units, hydrogen bonded to poly(γ -glutamic acid) (PGA), was developed to stimulate macrophage. Curdlan/PGA nanoparticles (C-NP) are formulated by physically blending curdlan (0.2 mg mL-1 in 0.4 m NaOH) with PGA (0.8 mg mL-1 ). Forster resonance energy transfer (FRET) analysis demonstrates a heterospecies interpolymer complex formed between curdlan and PGA. The 1 H-NMR spectra display significant peak broadening as well as downfield chemical shifts of the hydroxyl proton resonances of curdlan, indicating potential intermolecular hydrogen bonding interactions. In addition, the cross peaks in 1 H-1 H 2D-NOESY suggest intermolecular associations between the OH-2/OH-4 hydroxyl groups of curdlan and the carboxylic-/amide-groups of PGA via hydrogen bonding. Intracellular uptake of C-NP occurs over time in human monocyte-derived macrophage (MDM). Furthermore, C-NP nanoparticles dose-dependently increase gene expression for TNF-α, IL-6, and IL-8 at 24 h in MDM. C-NP nanoparticles also stimulate the release of IL-lß, MCP-1, TNF-α, IL-8, IL-12p70, IL-17, IL-18, and IL-23 from MDM. Overall, this is the first demonstration of a simplistic nanoformulation formed by hydrogen bonding between curdlan and PGA that modulates cytokine gene expression and release of cytokines from MDM.

Photoacoustic and Magnetic Resonance Imaging of Hybrid Manganese Dioxide-Coated Ultra-small NaGdF4 Nanoparticles for Spatiotemporal Modulation of Hypoxia in Head and Neck Cancer.

There is widespread interest in developing agents to modify tumor hypoxia in head and neck squamous cell carcinomas (HNSCC). Here, we report on the synthesis, characterization, and potential utility of ultra-small NaYF4:Nd3+/NaGdF4 nanocrystals coated with manganese dioxide (usNP-MnO2) for spatiotemporal modulation of hypoxia in HNSCC. Using a dual modality imaging approach, we first visualized the release of Mn2+ using T1-weighted magnetic resonance imaging (MRI) and modulation of oxygen saturation (%sO2) using photoacoustic imaging (PAI) in vascular channel phantoms. Combined MRI and PAI performed in patient-derived HNSCC xenografts following local and systemic delivery of the hybrid nanoparticles enabled mapping of intratumoral nanoparticle accumulation (based on T1 contrast enhancement) and improvement in tumor oxygenation (increased %sO2) within the tumor microenvironment. Our results demonstrate the potential of hybrid nanoparticles for the modulation of tumor hypoxia in head and neck cancer. Our findings also highlight the potential of combined MRI-PAI for simultaneous mapping nanoparticle delivery and oxygenation changes in tumors. Such imaging methods could be valuable in the precise selection of patients that are likely to benefit from hypoxia-modifying nanotherapies.

Dual Regioselective Targeting the Same Receptor in Nanoparticle-Mediated Combination Immuno/Chemotherapy for Enhanced Image-Guided Cancer Treatment.

When combined with immunotherapy, image-guided targeted delivery of chemotherapeutic agents is a promising direction for combination cancer theranostics, but this approach has so far produced only limited success due to a lack of molecular targets on the cell surface and low therapeutic index of conventional chemotherapy drugs. Here, we demonstrate a synergistic strategy of combination immuno/chemotherapy in conditions of dual regioselective targeting, implying vectoring of two distinct binding sites of a single oncomarker (here, HER2) with theranostic compounds having a different mechanism of action. We use: (i) PLGA nanoformulation, loaded with an imaging diagnostic fluorescent dye (Nile Red) and a chemotherapeutic drug (doxorubicin), and functionalized with affibody ZHER2:342 (8 kDa); (ii) bifunctional genetically engineered DARP-LoPE (42 kDa) immunotoxin comprising of a low-immunogenic modification of therapeutic Pseudomonas exotoxin A (LoPE) and a scaffold targeting protein, DARPin9.29 (14 kDa). According to the proposed strategy, the first chemotherapeutic nanoagent is targeted by the affibody to subdomain III and IV of HER2 with 60-fold specificity compared with nontargeted particles, while the second immunotoxin is effectively targeted by DARPin molecule to subdomain I of HER2. We demonstrate that this dual targeting strategy can enhance anticancer therapy of HER2-positive cells with a very strong synergy, which made possible 1000-fold decrease of effective drug concentration in vitro and a significant enhancement of HER2 cancer therapy compared to monotherapy in vivo. Moreover, this therapeutic combination prevented the appearance of secondary tumor nodes. Thus, the suggested synergistic strategy utilizing dual targeting of the same oncomarker could give rise to efficient methods for aggressive tumors treatment.

A Multimodal Theranostic Nanoformulation That Dramatically Enhances Docetaxel Efficacy Against Castration Resistant Prostate Cancer.

In this work, a multifunctional hierarchical nanoformulation composed of biodegradable chitosan (CS) coated poly (lactic-co-glycolic acid) (PLGA) nanocarriers loaded with docetaxel (Doc) and interleukin-8 (IL-8) small interfering RNA (siRNA) electrostatically bound to upconversion nanoparticles (UCNPs), is developed to treat castration-resistant prostate cancer (CRPC). This theranostic nanoformulation facilitates simultaneous delivery of chemotherapy and gene therapy, as well as a bimodal optical and magnetic resonance imaging agent that could enable image-guided combination therapy. Poly-d-lysine coated NaYF4; Yb20%, Er2%@NaYF4; Gd50% core@shell UCNPs are effective siRNA transfection agents, and Er3+ doping provides upconversion imaging capabilities, while Gd3+ doping enables magnetic resonance contrast enhancement. These properties are maintained upon encapsulation in PLGA-CS. PLGA-CS nanocarriers containing Doc and UCNP-siRNA are 235 ± 5 nm with a zeta potential of +17 ± 4 meV, and have a high Doc encapsulation efficiency of 57 ± 6%. Compared to free Doc, this PLGA-CS nanoformulation containing Doc and UCNP-siRNA exhibits a dramatic decrease in IC50 of ~14,000 fold (p < 0.001) through combination therapy in human PC-3 prostate cancer cells. This biocompatible, multimodal, theranostic nanoformulation demonstrates paradigm-shifting enhancement in anticancer activity over free Doc, with unique potential for use in image-guided combination therapy to treat CRPC.

Laser ablation for pharmaceutical nanoformulations: Multi-drug nanoencapsulation and theranostics for HIV.

We introduce the use of laser ablation to develop a multi-drug encapsulating theranostic nanoformulation for HIV-1 antiretroviral therapy. Laser ablated nanoformulations of ritonavir, atazanavir, and curcumin, a natural product that has both optical imaging and pharmacologic properties, were produced in an aqueous media containing Pluronic® F127. Cellular uptake was confirmed with the curcumin fluorescence signal localized in the cytoplasm. Formulations produced with F127 had improved water dispersibility, are ultrasmall in size (20-25 nm), exhibit enhanced cellular uptake in microglia, improve blood-brain barrier (BBB) crossing in an in vitro BBB model, and reduce viral p24 by 36 fold compared to formulations made without F127. This work demonstrates that these ultrasmall femtosecond laser-ablated nanoparticles are effective in delivering drugs across the BBB for brain therapy and show promise as an effective method to formulate nanoparticles for brain theranostics, reducing the need for organic solvents during preparation.

In vitro Pharmacokinetic Cell Culture System that Simulates Physiologic Drug and Nanoparticle Exposure to Macrophages.

PURPOSE: An in vitro dynamic pharmacokinetic (PK) cell culture system was developed to more precisely simulate physiologic nanoparticle/drug exposure. METHODS: A dynamic PK cell culture system was developed to more closely reflect physiologic nanoparticle/drug concentrations that are changing with time. Macrophages were cultured in standard static and PK cell culture systems with rifampin (RIF; 5 µg/ml) or ß-glucan, chitosan coated, poly(lactic-co-glycolic) acid (GLU-CS-PLGA) nanoparticles (RIF equivalent 5 µg/ml) for 6 h. Intracellular RIF concentrations were measured by UPLC/MS. Antimicrobial activity against M. smegmatis was tested in both PK and static systems. RESULTS: The dynamic PK cell culture system mimics a one-compartment elimination pharmacokinetic profile to properly mimic in vivo extracellular exposure. GLU-CS-PLGA nanoparticles increased intracellular RIF concentration by 37% compared to free drug in the dynamic cell culture system. GLU-CS-PLGA nanoparticles decreased M. smegmatis colony forming units compared to free drug in the dynamic cell culture system. CONCLUSIONS: The PK cell culture system developed herein enables more precise simulation of human PK exposure (i.e., drug dosing and drug elimination curves) based on previously obtained PK parameters.

Biodistribution and renal clearance of biocompatible lung targeted poly(ethylene glycol) (PEG) nanogel aggregates.

A novel stabilized aggregated nanogel particle (SANP) drug delivery system was prepared for injectable passive lung targeting. Gel nanoparticles (GNPs) were synthesized by irreversibly cross-linking 8 Arm PEG thiol with 1,6-hexane-bis-vinylsulfone (HBVS) in phosphate buffer (PB, pH 7.4) containing 0.1% v/v Tween™ 80. Aggregated nanogel particles (ANPs) were generated by aggregating GNPs to micron-size, which were then stabilized (i.e., SANPs) using a PEG thiol polymer to prevent further growth-aggregation. The size of SANPs, ANPs and GNPs was analyzed using a Coulter counter and transmission electron microscopy (TEM). Stability studies of SANPs were performed at 37°C in rat plasma, phosphate buffered saline (PBS, pH 7.4) and PB (pH 7.4). SANPs were stable in rat plasma, PBS and PB over 7 days. SANPs were covalently labeled with HiLyte Fluor™ 750 (DYE-SANPs) to facilitate ex vivo imaging. Biodistribution of intravenous DYE-SANPs (30 µm, 4 mg in 500 µL PBS) in male Sprague-Dawley rats was compared to free HiLyte Fluor™ 750 DYE alone (1mg in 500 µL PBS) and determined using a Xenogen IVIS® 100 Imaging System. Biodistribution studies demonstrated that free DYE was rapidly eliminated from the body by renal filtration, whereas DYE-SANPs accumulated in the lung within 30 min and persisted for 48 h. DYE-SANPs were enzymatically degraded to their original principle components (i.e., DYE-PEG-thiol and PEG-VS polymer) and were then eliminated from the body by renal filtration. Histological evaluation using H & E staining and broncho alveolar lavage (BAL) confirmed that these flexible SANPs were not toxic. This suggests that because of their flexible and non-toxic nature, SANPs may be a useful alternative for treating pulmonary diseases such as asthma, pneumonia, tuberculosis and disseminated lung cancer.

A series of alpha-amino acid ester prodrugs of camptothecin: in vitro hydrolysis and A549 human lung carcinoma cell cytotoxicity.

The objective of the present study was to identify a camptothecin (CPT) prodrug with optimal release and cytotoxicity properties for immobilization on a passively targeted microparticle delivery system. A series of alpha-amino acid ester prodrugs of CPT were synthesized, characterized, and evaluated. Four CPT prodrugs were synthesized with increasing aliphatic chain length (glycine (Gly) (2a), alanine (Ala) (2b), aminobutyric acid (Abu) (2c), and norvaline (Nva) (2d)). Prodrug reconversion was studied at pH 6.6, 7.0, and 7.4 corresponding to tumor, lung, and extracellular/physiological pH, respectively. Cytotoxicity was evaluated in A549 human lung carcinoma cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The hydrolytic reconversion rate to parent CPT increased with decreasing side chain length as well as increasing pH. The Hill slope of 2d was significantly less than CPT and the other prodrugs tested, indicating a higher cell death rate at lower concentrations. These results suggest that 2d is the best candidate for a passively targeted sustained release lung delivery system.

Pulmonary targeting microparticulate camptothecin delivery system: anticancer evaluation in a rat orthotopic lung cancer model.

Large (>6 microm) rigid microparticles (MPs) become passively entrapped within the lungs after intravenous (i.v.) injection making them an attractive and highly efficient alternative to inhalation for pulmonary delivery. In this study, PEGylated 6 microm polystyrene MPs with multiple copies of the norvaline (Nva) alpha-amino acid prodrug of camptothecin (CPT) were prepared. Surface morphology was characterized using a scanning electron microscope. CPT was released from the CPT-Nva-MPs over 24 h in rat plasma at 37 degrees C. In-vivo CPT plasma concentrations were low (approximately 1 ng/ml or less) and constant over a period of 4 days after a single i.v. injection of CPT-Nva-MPs as compared with high but short-lived systemic exposures after an i.v. injection of free CPT. This suggests that sustained local CPT concentrations were achieved in the lung after administration of the MP delivery system. Anticancer efficacy was evaluated in an orthotopic lung cancer animal model and compared with a bolus injection of CPT. Animals receiving free CPT (2 mg/kg) and CPT-Nva-MPs (0.22 mg/kg CPT and 100 mg/kg MPs) were found to have statistically significant smaller areas of lung cancer (P<0.05 and 0.01, respectively) than untreated animals. In addition, 40% of the animals receiving CPT-Nva-MPs were found to be free of cancer. The CPT dose using targeted MPs was 10 times lower than after i.v. injection of free CPT, but was more effective in reducing the amount of cancerous areas. In conclusion, CPT-Nva-MPs were able to achieve effective local lung and low systemic CPT concentrations at a dose that was 10 times lower than systemically administered CPT resulting in a significant improvement in anticancer efficacy in an orthotopic rat model of lung cancer.