Cell membrane inspired nano-shell enabling long-acting Glucose Oxidase for Melanoma starvation therapy via microneedles-based percutaneous delivery.

Rationale: Glucose oxidase (GOx) has gained tremendous research interest recently as a glucose-consuming enzyme for tumor starvation therapy, while its in vivo applications are strictly limited by rapid deactivation, as well as side effects of non-specific catalysis. Methods: To address these issues, here we report a protective nano-shell to encapsule GOx for localized melanoma therapy delivered by dissolving microneedles (MNs). Inspired by cell membrane that separates and protects cell organelles and components from outside environment while selectively ingesting nutrition sources, we designed polydopamine (PDA)-structured nano-shell to allow free transportation of glucose for catalytic reaction, while impede the penetration of GOx, proteinase, and other GOx-deactivating macromolecules across the shell membrane. Results: GOx was well protected in core layer with persistent catalytic activity for at least 6 d under various biological matrixes (e.g., PBS, serum, and cell lysate) and surviving different harsh conditions (e.g., acid/base treatments, and proteinase-induced degradation). Such long-acting nano-catalyst can be easily integrated into MNs as topical delivery carrier for effective glucose consumption in melanoma tissue, achieving significant tumor growth inhibition via starvation therapy with minimized side effects as compared to systemic administration. Conclusion: This work provides an elegant platform for in vivo delivery of GOx, and our cell-mimicking nano-system can also be applied for other enzyme-based therapeutics.

Synthetic Immunogenic Cell Death Mediated by Intracellular Delivery of STING Agonist Nanoshells Enhances Anticancer Chemo-immunotherapy.

Many favorable anticancer treatments owe their success to the induction immunogenic cell death (ICD) in cancer cells, which results in the release of endogenous danger signals along with tumor antigens for effective priming of anticancer immunity. We describe a strategy to artificially induce ICD by delivering the agonist of stimulator of interferon genes (STING) into tumor cells using hollow polymeric nanoshells. Following intracellular delivery of exogenous adjuvant, subsequent cytotoxic treatment creates immunogenic cellular debris that spatiotemporally coordinate tumor antigens and STING agonist in a process herein termed synthetic immunogenic cell death (sICD). sICD is indiscriminate to the type of chemotherapeutics and enables colocalization of exogenously administered immunologic adjuvants and tumor antigens for enhanced antigen presentation and anticancer adaptive response. In three mouse tumor models, sICD enhances therapeutic efficacy and restrains tumor progression. The study highlights the benefit of delivering STING agonists to cancer cells, paving ways to new chemo-immunotherapeutic designs.

Gold nanoshell-localized photothermal ablation of prostate tumors in a clinical pilot device study.

Biocompatible gold nanoparticles designed to absorb light at wavelengths of high tissue transparency have been of particular interest for biomedical applications. The ability of such nanoparticles to convert absorbed near-infrared light to heat and induce highly localized hyperthermia has been shown to be highly effective for photothermal cancer therapy, resulting in cell death and tumor remission in a multitude of preclinical animal models. Here we report the initial results of a clinical trial in which laser-excited gold-silica nanoshells (GSNs) were used in combination with magnetic resonance-ultrasound fusion imaging to focally ablate low-intermediate-grade tumors within the prostate. The overall goal is to provide highly localized regional control of prostate cancer that also results in greatly reduced patient morbidity and improved functional outcomes. This pilot device study reports feasibility and safety data from 16 cases of patients diagnosed with low- or intermediate-risk localized prostate cancer. After GSN infusion and high-precision laser ablation, patients underwent multiparametric MRI of the prostate at 48 to 72 h, followed by postprocedure mpMRI/ultrasound targeted fusion biopsies at 3 and 12 mo, as well as a standard 12-core systematic biopsy at 12 mo. GSN-mediated focal laser ablation was successfully achieved in 94% (15/16) of patients, with no significant difference in International Prostate Symptom Score or Sexual Health Inventory for Men observed after treatment. This treatment protocol appears to be feasible and safe in men with low- or intermediate-risk localized prostate cancer without serious complications or deleterious changes in genitourinary function.

Anti-EGFR antibody conjugated thiol chitosan-layered gold nanoshells for dual-modal imaging-guided cancer combination therapy.

Developing a novel multifunctional theranostic agent for cancer combination therapy has attracted tremendous attention in recent years. In this report, we designed and developed a new multifunctional nanocarrier based on anti-epidermal growth factor receptor antibody-conjugated and paclitaxel loaded-thiol chitosan-layered gold nanoshells (anti-EGFR-PTX-TCS-GNSs) as a theranostic agent for the first time used for fluorescence/photoacoustic dual-modal imaging-guided chemophotothermal synergistic therapy. The resulting anti-EGFR-PTX-TCS-GNSs showed excellent biosafety, biocompatibility, broad near-infrared (NIR) absorbance, photostability, fast and laser irradiation-controllable drug release, and higher targeting efficiency for efficient chemophotothermal combination therapy of cancer under the guidance of photoacoustic imaging (PAI). The combination therapy was investigated in vitro and in vivo, displaying a powerful anticancer efficiency. More importantly, an in vivo experiment of anti-EGFR-PTX-TCS-GNSs with laser irradiation showed heavy damage to the tumor tissue, killing the tumor cells almost completely. Anti-EGFR-PTX-TCS-GNSs also showed a powerful capacity to visualize tumors, and therefore it is considered a new PAI contrast agent for subsequent therapy. Histological analysis and TUNEL assay further showed much more apoptotic cells, confirming the value of anti-EGFR-PTX-TCS-GNSs. Our results provide a new concept and a promising strategy to develop a novel multifunctional nanotheranostic agent for future clinical applications in diagnosis and therapy.

Recent Developments of Supramolecular Metal-based Structures for Applications in Cancer Therapy and Imaging.

The biomedical application of discrete supramolecular metal-based structures, including supramolecular coordination complexes (SCCs), is still an emergent field of study. However, pioneering studies over the last 10 years demonstrated the potential of these supramolecular compounds as novel anticancer drugs, endowed with different mechanisms of action compared to classical small-molecules, often related to their peculiar molecular recognition properties. In addition, the robustness and modular composition of supramolecular metal-based structures allows for an incorporation of different functionalities in the same system to enable imaging in cells via different modalities, but also active tumor targeting and stimuli-responsiveness. Although most of the studies reported so far exploit these systems for therapy, supramolecular metal-based structures may also constitute ideal scaffolds to develop multimodal theranostic agents. Of note, the host-guest chemistry of 3D self-assembled supramolecular structures - within the metallacages family - can also be exploited to design novel drug delivery systems for anticancer chemotherapeutics. In this review, we aim at summarizing the pivotal concepts in this fascinating research area, starting with the main design principles and illustrating representative examples while providing a critical discussion of the state-of-the-art. A section is also included on supramolecular organometallic complexes (SOCs) whereby the (organic) linker is forming the organometallic bond to the metal node, whose biological applications are still to be explored. Certainly, the myriad of possible supramolecular metal-based structures and their almost limitless modularity and tunability suggests that the biomedical applications of such complex chemical entities will continue along this already promising path.

Synthesis, characterization and application of plasmonic hollow gold nanoshells in a photothermal therapy-New particles for theranostics.

This article describes the work on synthesis, surface functionalization and characterization of hollow gold nanoshells (HGNs), and their application in a photothermal tumor therapy. The studied gold nanoshells were synthesized using a method based on a reduction of HAuCl4 onto silver nanoparticle templates. A selected aptamer - AS1411 - selective towards nucleolin, with a terminal thiol group was conjugated to HGNs. Surface functionalization of synthesized nanoparticles was necessary to gain the affinity to tumor cells, thus allowing the selective delivery of the modified nanoparticles to target cells. As expected, an increased selectivity of nanoconjugates towards tumor cells (A375) in a comparison to normal ones (HaCaT) was observed (2.67 times). In the framework of our studies the biological activity of the obtained nanoconjugates was evaluated using MTT assay. For this aim, both normal and tumor cell cultures respresenting skin tissue were exposed to gold nanoparticles solutions. It was found, that HGN-AS1411 conjugates cause less than 10% loss in a cell viability in the case of both cell lines at the highest tested concentration. The potential of the developed nanoconjugates as agents in PTT of skin cancer was investigated in a subsequent stage of our research. It was found, that A375 cell viability amounted to less than 40% for 75µM of nanoconjugates (expressed as a concentration of Au atoms) as a result of the laser irradiation of this cell culture after desired accumulation of the tested nanoconjugates inside A375 cells.

Total Aqueous Synthesis of Au@Cu2-x S Core-Shell Nanoparticles for In Vitro and In Vivo SERS/PA Imaging-Guided Photothermal Cancer Therapy.

Both accurate tumor navigation and nanostructures with high photothermal (PT) conversion efficiency are important but remain challenging to achieve in current biomedical applications. This study reports an anion exchange-based facile and green approach for synthesizing Au@Cu2-x S core-shell nanoparticles (NPs) in an aqueous system. In addition to the PT effect of the suggested NPs, the surface-enhanced Raman scattering (SERS) is also significantly improved due to the tailored localized surface plasmon resonance coupling between the Au metal core and the Cu2-x S semiconductor shell. Using an epitaxial strategy, Au@Cu2 O NPs are first obtained by the in situ reduction of cupric hydroxide on a cresyl violet acetate-coated Au core; then, Au@Cu2-x S NPs are obtained via anion exchange between the S2- and Cu2 O shell. Both the Cu/S atomic ratio and the Cu2-x S shell thickness can be adjusted conveniently. Hence, the ideal integration of the plasmonic Au core and Cu2-x S shell into a single unit is conducive not only to highly efficient PT conversion but also to the construction of a SERS-based navigator. This new type of SERS-guided NP, with enhanced photoacoustic signals, is an important candidate for both accurate tumor navigation and nondestructive PT treatment guided in vivo by two modes of optical imaging.

In situ fabrication of mesoporous silica-coated silver-gold hollow nanoshell for remotely controllable chemo-photothermal therapy via phase-change molecule as gatekeepers.

This study reports a new strategy for in situ fabrication of plasmonic hollow silver-gold nanoshell (with resonance tuned to NIR region) encased in the hollow mesoporous silica as an efficient platform to efficiently and precisely regulate the release of 5-fluorouracil (anticancer drug) for prostate cancer therapy and photothermal therapy. The mesopores were capped with thermosensitive phase-change material lauric acid, which allowed for remote, precise, and spatiotemporal control of drug release via external heating or photothermal heating of plasmonic silver-gold nanoshell via NIR laser irradiation. The system was nanometric, monodispersed, and showed negative surface charge. The nanocarrier showed better pH stability and thermodynamic stability compared to dense silica-coated gold nanoshells. The drug release could be triggered remotely by applying low powered continuous wave NIR laser (λ = 808 nm). The nanocarrier showed improved internalization by cancer cells, which was further enhanced by laser irradiation. High powered laser directly killed the cancer cells via photothermal effect in the region irradiated. Thus, this system fabricated by novel synthetic strategy provided efficient chemo- and phototherapy.

Multifunctional Porous Iron Oxide Nanoagents for MRI and Photothermal/Chemo Synergistic Therapy.

Nanoagents of integrating multiple imaging and therapeutic modalities have attracted tremendous attention for biomedical applications. Herein, we synthesize porous hollow Fe3O4 as a theranostic agent for MRI and combined photothermal/chemo cancer therapy. The as-prepared porous iron oxide nanoagents allow for T2-weighted MR imaging. Interestingly, we demonstrate that the porous structure endows the nanoagents an outstanding photothermal property for cancer cell killing, in comparison with other types of iron oxide nanomaterials. Under the exposure of an NIR laser, the heat produced by porous Fe3O4 can accelerate the release of the loaded drug (e.g., DOX) to enhance chemotherapeutic efficacy, promoting the ablation of cancer cells with synergistic photothermal/chemotherapy.

Photothermal Therapy Employing Gold Nanoparticle- Loaded Macrophages as Delivery Vehicles: Comparing the Efficiency of Nanoshells Versus Nanorods.

Macrophages (Ma) loaded with gold based nanoparticles, which convert near infrared light to heat, have been studied as targeted transport vectors for photothermal therapy (PTT) of tumors. The purpose of the experiments reported here was to compare the efficacy of gold-silica nanoshells (AuNS) and gold nanorods (AuNR) in macrophage mediated PTT. PTT efficacy was evaluated in hybrid glioma spheroids consisting of human glioma cells and either AuNS or AuNR loaded Ma, designated MaNS and MaNR respectivly. Spheroids were irradiated for 10 min. with light from an 810 nm diode laser at irradiances ranging from 0 to 28 W/cm2. PTT efficacy was determined from spheroid growth over a 14-day period. The uptake by Ma of pegylated AuNR (3.9 ± 0.9 %) was twice that of pegylated AuNS, (7.9 ± 0.7 %). Hybrid spheroids consisting of a 5:1 ratio of glioma cells to loaded Ma exhibited significant growth inhibition with MaNS when subjected to irradiances of 7 W/cm2 or greater. In contrast, no significant growth inhibition was observed for the MaNR hybrid spheroids at this 5:1 ratio, even at the highest irradiance investigated (28 W/cm2). Although AuNR were taken up by Ma in larger numbers then AuNS, MaNS were shown to have greater PTT efficacy compared to MaNR for equivalent numbers of loaded Ma.

Gold nanorod-based poly(lactic-co-glycolic acid) with manganese dioxide core-shell structured multifunctional nanoplatform for cancer theranostic applications.

Recently, photothermal therapy has become a promising strategy in tumor treatment. However, the therapeutic effect was seriously hampered by the low tissue penetration of laser. Therefore, in this study, radiofrequency (RF) with better tissue penetration was used for tumor hyperthermia. First, one type of gold nanorods (AuNRs) suitable for RF hyperthermia was selected. Then, poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with AuNRs and docetaxel (DTX) (PLGA/AuNR/DTX) NPs were constructed. Finally, manganese dioxide (MnO2) ultrathin nanofilms were coated on the surfaces of PLGA/AuNR/DTX NPs by the reduction of KMnO4 to construct the PLGA/AuNR/DTX@MnO2 drug delivery system. This drug delivery system can not only be used for the combined therapy of chemotherapy and RF hyperthermia but can also produce Mn2+ to enable magnetic resonance imaging. Furthermore, the RF hyperthermia and the degradation of MnO2 can significantly promote the controlled drug release in a tumor region. The in vitro and in vivo results suggested that the PLGA/AuNR/DTX@MnO2 multifunctional drug delivery system is a promising nanoplatform for effective cancer theranostic applications.

Assessment of in vivo systemic toxicity and biodistribution of iron-doped silica nanoshells.

Silica nanoparticles are an emerging class of biomaterials which may be used as diagnostic and therapeutic tools for biomedical applications. In particular, hollow silica nanoshells are attractive due to their hollow core. Approximately 70% of a 500 nm nanoshell is hollow, therefore more particles can be administered on a mg/kg basis compared to solid nanoparticles. Additionally, their nanoporous shell permits influx/efflux of gases and small molecules. Since the size, shape, and composition of a nanoparticle can dramatically alter its toxicity and biodistribution, the toxicology of these nanomaterials was assessed. A single dose toxicity study was performed in vivo to assess the toxicity of 500 nm iron-doped silica nanoshells at clinically relevant doses of 10-20 mg/kg. This study showed that only a trace amount of silica was detected in the body 10 weeks post-administration. The hematology, biochemistry and pathological results show that the nanoshells exhibit no acute or chronic toxicity in mice.

Synergistic Chemo-Photothermal Therapy of Breast Cancer by Mesenchymal Stem Cell-Encapsulated Yolk-Shell GNR@HPMO-PTX Nanospheres.

Mesenchymal stem cells (MSCs) have attracted increasing attention as vehicles for cancer treatment. Herein, MSC-based synergistic oncotherapy strategy is presented for the first time. To achieve this goal, yolk-shell structured gold nanorod embedded hollow periodic mesoporous organosilica nanospheres (GNR@HPMOs) with high paclitaxel (PTX) loading capability and excellent photothermal transfer ability upon near-infrared (NIR) light irradiation are first prepared. Cytotoxicity and migration assays show that the viability and tumor-homing capability of MSCs are well-retained after internalization of high content of PTX loaded GNR@HPMOs (denoted as GNR@HPMOs-PTX). In vitro experiments show the GNR@HPMOs-PTX loaded MSCs (GNR@HPMOs-PTX@MSCs) possess synergistic chemo-photothermal killing effects for breast cancer cells. Also, photoacoustic imaging shows that the MSCs can improve dispersion and distribution in tumor tissue for GNR@HPMOs-PTX after intratumoral injection. In vivo experiments in breast cancer model of nude mice further demonstrate that the GNR@HPMOs-PTX@MSCs significantly inhibit tumor growth, suggesting their great potential for synergistic therapy of cancer.

Catalase-Loaded TaOx Nanoshells as Bio-Nanoreactors Combining High-Z Element and Enzyme Delivery for Enhancing Radiotherapy.

A novel type of bio-nanoreactor with catalase loaded inside TaOx hollow nanoshells is fabricated via a mild one-step method. Such bio-nanoreactors could efficiently improve the tumor oxygenation by supplying oxygen via decomposition of endogenic H2 O2 in a tumor microenvironment, and thus synergistically enhance the efficacy of cancer radiotherapy by both depositing radiation energy within the tumor and overcoming hypoxia-induced radiotherapy resistance.

Detection of Phosphatidylcholine-Coated Gold Nanoparticles in Orthotopic Pancreatic Adenocarcinoma using Hyperspectral Imaging.

Nanoparticle uptake and distribution to solid tumors are limited by reticuloendothelial system systemic filtering and transport limitations induced by irregular intra-tumoral vascularization. Although vascular enhanced permeability and retention can aid targeting, high interstitial fluid pressure and dense extracellular matrix may hinder local penetration. Extravascular diffusivity depends upon nanoparticle size, surface modifications, and tissue vascularization. Gold nanoparticles functionalized with biologically-compatible layers may achieve improved uptake and distribution while enabling cytotoxicity through synergistic combination of chemotherapy and thermal ablation. Evaluation of nanoparticle uptake in vivo remains difficult, as detection methods are limited. We employ hyperspectral imaging of histology sections to analyze uptake and distribution of phosphatidylcholine-coated citrate gold nanoparticles (CGN) and silica-gold nanoshells (SGN) after tail-vein injection in mice bearing orthotopic pancreatic adenocarcinoma. For CGN, the liver and tumor showed 26.5 ± 8.2 and 23.3 ± 4.1 particles/100 µm2 within 10 µm from the nearest source and few nanoparticles beyond 50 µm, respectively. The spleen had 35.5 ± 9.3 particles/100 µm2 within 10 µm with penetration also limited to 50 µm. For SGN, the liver showed 31.1 ± 4.1 particles/100 µm2 within 10 µm of the nearest source with penetration hindered beyond 30 µm. The spleen and tumor showed uptake of 22.1 ± 6.2 and 15.8 ± 6.1 particles/100 µm2 within 10 µm, respectively, with penetration similarly hindered. CGH average concentration (nanoparticles/µm2) was 1.09 ± 0.14 in the liver, 0.74 ± 0.12 in the spleen, and 0.43 ± 0.07 in the tumor. SGN average concentration (nanoparticles/µm2) was 0.43 ± 0.07 in the liver, 0.30 ± 0.06 in the spleen, and 0.20 ± 0.04 in the tumor. Hyperspectral imaging of histology sections enables analysis of phosphatidylcholine-coated gold-based nanoparticles in pancreatic tumors with the goal to improve nanotherapeutic efficacy.

Oral absorption of PEG-coated versus uncoated gold nanospheres: does agglomeration matter?

BACKGROUND: Particle size is thought to be a critical factor affecting the bioavailability of nanoparticles following oral exposure. Nearly all studies of nanoparticle bioavailability focus on characterization of the primary particle size of the material as supplied or as dosed, and not on agglomeration behavior within the gastrointestinal tract, which is presumably most relevant for absorption. METHODS: In the study reported here, snapshots of agglomeration behavior of gold nanospheres were evaluated in vivo throughout the gastrointestinal tract using transmission electron microscopy. Agglomeration state within the gastrointestinal tract was then used to help explain differences in gastrointestinal particle absorption, as indicated by tissue levels of gold detected using inductively coupled plasma mass spectrometry. Mice were dosed (10 mg/kg) with either 23 nm PEG-coated or uncoated gold nanospheres. RESULTS: Transmission electron microscopy demonstrates that PEG-coated gold nanoparticles can be observed as primary, un-agglomerated particles throughout the gastrointestinal tract and feces of dosed animals. In contrast, uncoated gold nanoparticles were observed to form agglomerates of several hundred nanometers in all tissues and feces. Inductively coupled plasma mass spectrometry shows significantly higher levels of gold in tissues from animals dosed with PEG-coated versus uncoated 23 nm gold nanoparticles. Retention of particles after a single oral gavage was also very high, with all tissues of animals dosed with PEG-coated particles having detectable levels of gold at 30 days following exposure. CONCLUSIONS: Qualitative observation of these particles in vivo shows that dispersed PEG-coated particles are able to reach the absorptive tissues of the intestine while agglomerated uncoated particles are sequestered in the lumen of these tissues. However, the large differences observed for in vivo agglomeration behavior were not reflected in oral absorption, as indicated by gold tissue levels. Additional factors, such as surface chemistry, may have played a more important role than in vivo particle size and should be investigated further.

Nanoparticle-loaded macrophage-mediated photothermal therapy: potential for glioma treatment.

Gold-based nanoparticles have been used in a number of therapeutic and diagnostic applications. The purpose of this study was to investigate the efficacy of gold-silica nanoshells (AuNS) in photothermal therapy (PTT) of rat gliomas. Rat alveolar macrophages (Ma) were used as nanoparticle delivery vectors. Uptake of AuNS (bare and PEGylated) was investigated in Ma. AuNS were incubated with Ma for 24 h. Phase contrast microscopy was used to visualize the distribution of loaded Ma in three-dimensional glioma spheroids. PTT efficacy was evaluated for both empty (Ma) and AuNS-loaded Ma (Ma(NS)) in both monolayers and spheroids consisting of C6 rat glioma cells and Ma. Monolayers/spheroids were irradiated for 5 min with light from an 810-nm diode laser at irradiances ranging from 7 to 28 W cm(-2). Monolayer survival was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay while PTT efficacy in spheroids was determined from growth kinetics and live/dead fluorescence microscopy. PTT efficacy was investigated in vivo using a Sprague-Dawley rat glioma model. Five rats received direct intracranial injection of a mixture of 10(4) C6 glioma cells and, 2 days later, an equal number of Ma(NS). Three rats received laser treatment (810 nm; 10 min; 1 W) while the remaining two served as controls (no laser treatment). The uptake ratio of bare to PEGylated AuNS by Ma was 4:1. A significant photothermal effect was observed in vitro, albeit at relatively high radiant exposures (2.1-4.2 kJ cm(-2)). PTT proved effective in vivo in preventing or delaying tumor development in the PTT-treated animals.

Ultrasonic delivery of silica-gold nanoshells for photothermolysis of sebaceous glands in humans: Nanotechnology from the bench to clinic.

Recent advances in nanotechnology have provided numerous opportunities to transform medical therapies for the treatment of diseases including cancer, atherosclerosis, and thrombosis. Here, we report, through in vitro studies and in vivo human pilot clinical studies, the use of inert, inorganic silica-gold nanoshells for the treatment of a widely prevalent and researched, yet poorly treated disease of acne. We use ~150nm silica-gold nanoshells, tuned to absorb near-IR light and near-IR laser irradiation to thermally disrupt overactive sebaceous glands in the skin which define the etiology of acne-related problems. Low-frequency ultrasound was used to facilitate deep glandular penetration of the nanoshells. Upon delivery of the nanoshells into the follicles and glands, followed by wiping of superficial nanoshells from skin surface and exposure of skin to near-infrared laser, nanoshells localized in the follicles absorb light, get heated, and induce focal thermolysis of sebaceous glands. Pilot human clinical studies confirmed the efficacy of ultrasonically-delivered silica-gold nanoshells in inducing photothermal disruption of sebaceous glands without damaging collateral skin.

Multifunctional core/shell nanoparticles cross-linked polyetherimide-folic acid as efficient Notch-1 siRNA carrier for targeted killing of breast cancer.

In gene therapy, how genetic therapeutics can be efficiently and safely delivered into target tissues/cells remains a major obstacle to overcome. To address this issue, nanoparticles consisting of non-covalently coupled polyethyleneimine (PEI) and folic acid (FA) to the magnetic and fluorescent core/shell of Fe3O4@SiO2(FITC) was tested for their ability to deliver Notch-1 shRNA. Our results showed that Fe3O4@SiO2(FITC)/PEI-FA/Notch-1 shRNA nanoparticles are 64 nm in diameter with well dispersed and superparamagnetic. These nanoparticles with on significant cytotoxicity are capable of delivering Notch-1 shRNA into human breast cancer MDA-MB-231 cells with high efficiency while effectively protected shRNA from degradation by exogenous DNaseI and nucleases. Magnetic resonance (MR) imaging and fluorescence microscopy showed significant preferential uptake of Fe3O4@SiO2(FITC)/PEI-FA/Notch-1 shRNA nanocomplex by MDA-MB-231 cells. Transfected MDA-MB-231 cells exhibited significantly decreased expression of Notch-1, inhibited cell proliferation, and increased cell apoptosis, leading to the killing of MDA-MB-231 cells. In light of the magnetic targeting capabilities of Fe3O4@SiO2(FITC)/PEI-FA, our results show that by complexing with a second molecular targeting therapeutic, such as Notch-1 shRNA in this report, Fe3O4@SiO2(FITC)/PEI-FA can be exploited as a novel, non-viral, and concurrent targeting delivery system for targeted gene therapy as well as for MR imaging in cancer diagnosis.

Hydrogel-nanoparticle composites for optically modulated cancer therapeutic delivery.

A poly(N-isopropylacrylamide-co-acrylamide) (NIPAAm-co-AAm) hydrogel with near-infrared (NIR) absorbing silica-gold nanoshells was designed as a platform for pulsatile delivery of cancer therapeutics. This hydrogel was designed to have a lower critical solution temperature (LCST) above physiologic temperature, such that the material will transition from a hydrated state to a collapsed state above ~40°C. Additionally, the silica-gold nanoshells used were designed to have a peak extinction coefficient in the NIR, where penetration of light through tissue is maximal. This heat-triggered material phase transition of the composite was found to follow exposure of NIR light, indicating the ability of the NIR absorption by the nanoshells to sufficiently drive this transition. The composite material was loaded with either doxorubicin or a DNA duplex (a model nucleic acid therapeutic), two cancer therapeutics with differing physical and chemical properties. Release of both therapeutics was dramatically enhanced by NIR light exposure, causing 2-5x increase in drug release. Drug delivery profiles were influenced by both the molecular size of the drug as well as its chemical properties. The DNA therapeutic showed slower rates of nonspecific delivery by passive diffusion due to its larger size. Additionally, only 70% of the more hydrophobic doxorubicin was released from the material, whereas the more hydrophilic DNA showed over 90% release. Further, hydrogel composites were used to deliver the doxorubicin to CT.26-WT colon carcinoma cells, eliciting a therapeutic response. This work validates the potential application for this material in site-specific cancer therapeutic delivery.