Gene silencing by gold nanoshell-mediated delivery and laser-triggered release of antisense oligonucleotide and siRNA

Nanoparticle-mediated delivery of siRNA for effective lung cancer therapy

Lung cancer is one of the most lethal diseases worldwide, and the survival rate is less than 15% even after the treatment. Unfortunately, chemotherapeutic treatments for lung cancer are accompanied by severe side effects, lack of selectivity and multidrug resistance. In order to overcome the limitations of conventional chemotherapy, nanoparticle-mediated RNA interference drugs represent a potential new approach due to selective silencing effect of oncogenes and multidrug resistance related genes. In this review, we provide recent advancements on nanoparticle-mediated siRNA delivery strategies including lipid system, polymeric system and rigid nanoparticles for lung cancer therapies. Importantly, codelivery of siRNA with conventional anticancer drugs and recent theranostic agents that offer great potential for lung cancer therapy is covered.

Carbon nanomaterials combined with metal nanoparticles for theranostic applications

Among targeted delivery systems, platforms with nanosize dimensions, such as carbon nanomaterials (CNMs) and metal nanoparticles (NPs), have shown great potential in biomedical applications. They have received considerable interest in recent years, especially with respect to their potential utilization in the field of cancer diagnosis and therapy. The many functions of nanomaterials provide opportunities to use them as multimodal agents for theranostics, a combination of therapy and diagnosis. Carbon nanotubes and graphene are some of the most widely used CNMs because of their unique structural and physicochemical properties. Their high specific surface area allows for efficient drug loading and the possibility of functionalization with various bioactive molecules. In addition, CNMs are ideal platforms for the attachment of NPs. In the biomedical field, NPs have also shown tremendous potential for use in drug delivery, non-invasive tumour imaging and early detection due to their optical and magnetic properties. NP/CNM hybrids not only combine the unique properties of the NPs and CNMs but they also exhibit new properties arising from interactions between the two entities. In this review, the preparation of CNMs conjugated to different types of metal NPs and their applications in diagnosis, imaging, therapy and theranostics are presented.

Dissecting the molecular mechanism of apoptosis during photothermal therapy using gold nanoprisms

The photothermal response of plasmonic nanomaterials can be exploited for a number of biomedical applications in diagnostics (biosensing and optoacoustic imaging) and therapy (drug delivery and photothermal therapy). The most common cellular response to photothermal cancer treatment (ablation of solid tumors) using plasmonic nanomaterials is necrosis, a process that releases intracellular constituents into the extracellular milieu producing detrimental inflammatory responses. Here we report the use of laser-induced photothermal therapy employing gold nanoprisms (NPRs) to specifically induce apoptosis in mouse embryonic fibroblast cells transformed with the SV40 virus. Laser-irradiated "hot" NPRs activate the intrinsic/mitochondrial pathway of apoptosis (programmed cell death), which is mediated by the nuclear-encoded proteins Bak and Bax through the activation of the BH3-only protein Bid. We confirm that an apoptosis mechanism is responsible by showing how the NPR-mediated cell death is dependent on the presence of caspase-9 and caspase-3 proteins. The ability to selectively induce apoptotic cell death and to understand the subsequent mechanisms provides the foundations to predict and optimize NP-based photothermal therapy to treat cancer patients suffering from chemo- and radioresistance.

Off to the organelles - killing cancer cells with targeted gold nanoparticles

Gold nanoparticles (AuNPs) are excellent tools for cancer cell imaging and basic research. However, they have yet to reach their full potential in the clinic. At present, we are only beginning to understand the molecular mechanisms that underlie the biological effects of AuNPs, including the structural and functional changes of cancer cells. This knowledge is critical for two aspects of nanomedicine. First, it will define the AuNP-induced events at the subcellular and molecular level, thereby possibly identifying new targets for cancer treatment. Second, it could provide new strategies to improve AuNP-dependent cancer diagnosis and treatment.

Our review summarizes the impact of AuNPs on selected subcellular organelles that are relevant to cancer therapy. We focus on the nucleus, its subcompartments, and mitochondria, because they are intimately linked to cancer cell survival, growth, proliferation and death. While non-targeted AuNPs can damage tumor cells, concentrating AuNPs in particular subcellular locations will likely improve tumor cell killing. Thus, it will increase cancer cell damage by photothermal ablation, mechanical injury or localized drug delivery. This concept is promising, but AuNPs have to overcome multiple hurdles to perform these tasks. AuNP size, morphology and surface modification are critical parameters for their delivery to organelles. Recent strategies explored all of these variables, and surface functionalization has become crucial to concentrate AuNPs in subcellular compartments.

Here, we highlight the use of AuNPs to damage cancer cells and their organelles. We discuss current limitations of AuNP-based cancer research and conclude with future directions for AuNP-dependent cancer treatment.

Polymer/gold hybrid nanoparticles: from synthesis to cancer theranostic applications

This minireview highlights the preparation methods for various polymer/AuNP hybrids and the recent progress on their cancer theranostic applications.

Multifunctional nanoparticles: recent progress in cancer therapeutics

In recent times, several biocompatible nanomaterials with different morphologies and compositions, such as metals, metal oxides, and polymers, have been employed as multi-functional biomaterials to target cancer cells.

Non viral vectors in gene therapy- an overview

Non-viral vectors are simple in theory but complex in practice. Apart from intra cellular and extracellular barriers, number of other challenges also needs to be overcome in order to increase the effectiveness of non-viral gene transfer. These barriers are categorized as production, formulation and storage. No one-size-fits-all solution to gene delivery, which is why in spite of various developments in liposome, polymer formulation and optimization, new compounds are constantly being proposed and investigated. In this review, we will see in detail about various types of non-viral vectors highlighting promising development and recent advances that had improved the non-viral gene transfer efficiency of translating from "Bench to bedside".

How do organic gold compounds and organic halogen molecules interact? Comparison with hydrogen bonds

Au⋯halogen interactions exist extensively in crystal materials and exhibit some similar and different properties with hydrogen bonds.

Targeted intracellular delivery of proteins with spatial and temporal control

While a host of methods exist to deliver genetic materials or small molecules to cells, very few are available for protein delivery to the cytosol. We describe a modular, light-activated nanocarrier that transports proteins into cells by receptor-mediated endocytosis and delivers the cargo to the cytosol by light triggered endosomal escape. The platform is based on hollow gold nanoshells (HGN) with polyhistidine tagged proteins attached through an avidity-enhanced, nickel chelation linking layer; here, we used green fluorescent protein (GFP) as a model deliverable cargo. Endosomal uptake of the GFP loaded nanocarrier was mediated by a C-end Rule (CendR) internalizing peptide fused to the GFP. Focused femtosecond pulsed-laser excitation triggered protein release from the nanocarrier and endosome disruption, and the released protein was capable of targeting the nucleoli, a model intracellular organelle. We further demonstrate the generality of the approach by loading and releasing Sox2 and p53. This method for targeting of individual cells, with resolution similar to microinjection, provides spatial and temporal control over protein delivery.

Rapid, Reversible Release from Thermosensitive Liposomes Triggered by Near-Infra-Red Light

We present a novel drug carrier consisting of plasmonic hollow gold nanoshells (HGN) chemically tethered to liposomes made temperature sensitive with lysolipids (LTSL). Continuous-wave irradiation by physiologically friendly near infra-red light at 800 nm for 2.5 minutes at laser intensities an order of magnitude below that known to damage skin generates heating localized to the liposome membrane. The heating increases the liposome permeability in an irradiation dose-dependent, but reversible manner, resulting in rapid release of small molecules such as the self-quenching dye carboxyfluorescein or the chemotherapeutic doxorubicin, without raising the bulk temperature. The local rise in nanoshell temperature under laser irradiation was inferred by comparing dye release rates from the LTSL via bulk heating to that induced by irradiation. Laser-irradiation of LTSL enables precise control of contents release with low temperature gradients confined to areas irradiated by the laser focus. The combined effects of rapid local release and localized hyperthermia provide a synergistic effect as shown by a near doubling of androgen resistant PPC-1 prostate cancer cell toxicity compared to the same concentration of free doxorubicin.

Ultrasound-propelled nanoporous gold wire for efficient drug loading and release

Ultrasound (US)-powered nanowire motors based on nanoporous gold segment are developed for increasing the drug loading capacity. The new highly porous nanomotors are characterized with a tunable pore size, high surface area, and high capacity for the drug payload. These nanowire motors are prepared by template membrane deposition of a silver-gold alloy segment followed by dealloying the silver component. The drug doxorubicin (DOX) is loaded within the nanopores via electrostatic interactions with an anionic polymeric coating. The nanoporous gold structure also facilitates the near-infrared (NIR) light controlled release of the drug through photothermal effects. Ultrasound-driven transport of the loaded drug toward cancer cells followed by NIR-light triggered release is illustrated. The incorporation of the nanoporous gold segment leads to a nearly 20-fold increase in the active surface area compared to common gold nanowire motors. It is envisioned that such US-powered nanomotors could provide a new approach to rapidly and efficiently deliver large therapeutic payloads in a target-specific manner.

Photocontrolled nanoparticle delivery systems for biomedical applications

"Smart" stimuli-responsive nanomaterials are becoming popular as targeted delivery systems because they allow the use of internal or external stimuli to achieve spatial or temporal control over the delivery process. Among the stimuli that have been used, light is of special interest because it is not only noninvasive but also controllable both spatially and temporally, thus allowing unprecedented control over the delivery of bioactive molecules such as nucleic acids, proteins, drugs, etc. This is particularly advantageous for biomedical applications where specificity and selectivity are highly desired. Several strategies have evolved under the umbrella of light based delivery systems and can be classified into three main groups. The first strategy involves "caging" of the bioactive molecule using photolabile groups, loading these caged molecules onto a carrier and then "uncaging" or activating them at the targeted site upon irradiation with light of a particular wavelength. The second strategy makes use of nanocarriers that themselves are made photoresponsive either through modification with photosensitive groups or through the attachment of photolinkers on the carrier surface. These nanoparticles upon irradiation dissociate, releasing the cargo encapsulated within, or the photolinkers attaching the cargo to the surface get cleaved, resulting in release. The third approach makes use of the surface plasmon resonance of noble metal based nanoparticles. Upon irradiation with light at the plasmon resonant frequency, the resulting thermal or nonthermal field enhancement effects facilitate the release of bioactive molecules loaded onto the nanoparticles. In addition, other materials, certain metal sulfides, graphene oxide, etc., also exhibit photothermal transduction that can be exploited for targeted delivery. These approaches, though effective, are constrained by their predominant use of UV or visible light to which most photolabile groups are sensitive. Near infrared (NIR) excitation is preferred because NIR light is safer and can penetrate deeper in biological tissues. However, most photolabile groups cannot be excited by NIR light directly. So light conversion from NIR to UV/visible is required. Nanomaterials that display upconversion or two-photon-excitation properties have been developed that can serve as nanotransducers, converting NIR to UV/visible light to which the aforementioned photoresponsive moieties are sensitive. This Account will review the existing light-based nanoparticle delivery systems, their applications, the limitations they face, and the technologies that have emerged in an effort to overcome these limitations.

A promising road with challenges: where are gold nanoparticles in translational research?

Nanoenabled technology holds great potential for health issues and biological research. Among the numerous inorganic nanoparticles that are available today, gold nanoparticles are fully developed as therapeutic and diagnostic agents both in vitro and in vivo due to their physicochemical properties. Owing to this, substantial work has been conducted in terms of developing biosensors for noninvasive and targeted tumor diagnosis and treatment. Some studies have even expanded into clinical trials. This article focuses on the fundamentals and synthesis of gold nanoparticles, as well as the latest, most promising applications in cancer research, such as molecular diagnostics, immunosensors, surface-enhanced Raman spectroscopy and bioimaging. Challenges to their further translational development are also discussed.

Functional nanostructures for effective delivery of small interfering RNA therapeutics

Small interfering RNA (siRNA) has proved to be a powerful tool for target-specific gene silencing via RNA interference (RNAi). Its ability to control targeted gene expression gives new hope to gene therapy as a treatment for cancers and genetic diseases. However, siRNA shows poor pharmacological properties, such as low serum stability, off-targeting, and innate immune responses, which present a significant challenge for clinical applications. In addition, siRNA cannot cross the cell membrane for RNAi activity because of its anionic property and stiff structure. Therefore, the development of a safe, stable, and efficient system for the delivery of siRNA therapeutics into the cytoplasm of targeted cells is crucial. Several nanoparticle platforms for siRNA delivery have been developed to overcome the major hurdles facing the therapeutic uses of siRNA. This review covers a broad spectrum of non-viral siRNA delivery systems developed for enhanced cellular uptake and targeted gene silencing in vitro and in vivo and discusses their characteristics and opportunities for clinical applications of therapeutic siRNA.

Cancer theranostics with gold nanoshells

Gold nanoshells (AuNSs) present a vivid example of integrating nanoscience in order to solve a biomedical problem. AuNSs exhibit tunable surface plasmon resonance, which can be tuned to the near-infrared region in order to realize optimal tissue penetration. The highly efficient light-to-heat transformation by AuNSs during laser irradiation causes thermal damage to the tumor without damaging healthy organs. Transient nanobubbles can form around AuNSs during laser treatment and induce mechanical stress specifically in tumor cells. AuNSs also serve as a versatile platform for the delivery of various diagnostic and therapeutic agents. In this article, we describe the physicochemical properties of AuNSs in the context of their design, preparation and application in cancer theranostics. Ultimately, we look beyond the current research on AuNSs and discussed future challenges to their successful translation into clinical use.

siRNA delivery to the lung: what's new?

RNA interference (RNAi) has been thought of as the general answer to many unmet medical needs. After the first success stories, it soon became obvious that short interfering RNA (siRNA) is not suitable for systemic administration due to its poor pharmacokinetics. Therefore local administration routes have been adopted for more successful in vivo RNAi. This paper reviews nucleic acid modifications, nanocarrier chemistry, animal models used in successful pulmonary siRNA delivery, as well as clinical translation approaches. We summarize what has been published recently and conclude with the potential problems that may still hamper the efficient clinical application of RNAi in the lung.

Revisiting 30 years of biofunctionalization and surface chemistry of inorganic nanoparticles for nanomedicine

In the last 30 years we have assisted to a massive advance of nanomaterials in material science. Nanomaterials and structures, in addition to their small size, have properties that differ from those of larger bulk materials, making them ideal for a host of novel applications. The spread of nanotechnology in the last years has been due to the improvement of synthesis and characterization methods on the nanoscale, a field rich in new physical phenomena and synthetic opportunities. In fact, the development of functional nanoparticles has progressed exponentially over the past two decades. This work aims to extensively review 30 years of different strategies of surface modification and functionalization of noble metal (gold) nanoparticles, magnetic nanocrystals and semiconductor nanoparticles, such as quantum dots. The aim of this review is not only to provide in-depth insights into the different biofunctionalization and characterization methods, but also to give an overview of possibilities and limitations of the available nanoparticles.

Mn-porphyrin conjugated Au nanoshells encapsulating doxorubicin for potential magnetic resonance imaging and light triggered synergistic therapy of cancer

A theranostic agent was successfully fabricated by the formation of Au nanoshell around poly(lactic acid) nanoparticles entrapping doxorubicin, followed by linking a Mn-porphyrin derivative on the Au shell surface through polyethylene glycol. The resulted agent exhibited excellent colloidal stability and long blood circulation time due to introducing polyethylene glycol. The grafting Mn-porphyrin onto the nanoparticle surface endowed a greatly improved relaxivity (r1 value of 22.18 mM(-1)s(-1) of Mn(3+)), favorable for accurate cancer diagnosing and locating the tumor site to guide the external near infrared (NIR) laser irradiation for photothermal ablation of tumors. The in vitro experiments confirmed that the agent exhibited an efficient photohyperthermia and a light triggered and stepwise release behavior of doxorubicin due to the high NIR light absorption coefficient of Au nanoshell. The in vivo experiments showed that the combination of chemotherapy and photothermal therapy through such theranostic agent offered a synergistically improved therapeutic outcome compared with either therapy alone, making it a promising approach for cancer therapy. Therefore, such theranostic agent can be developed as a smart and promising nanosystemplatform that integrates multiple capabilities for both effective contrast enhanced magnetic resonance imaging and synergistic therapy.

Light-activatable gold nanoshells for drug delivery applications

Gold nanoshells (AuNSs) are currently being investigated as nanocarriers for drug delivery systems and have both diagnostic and therapeutic applications, including photothermal ablation, hyperthermia, drug delivery, and diagnostic imaging, particularly in oncology. AuNSs are valuable for their localized surface plasmon resonance, biocompatibility, low immunogenicity, and facile functionalization. AuNSs used for drug delivery can be spatially and temporally triggered to release controlled quantities of drugs inside the target cells when illuminated with a near-infrared (NIR) laser. Recently, many research groups have demonstrated that these AuNS complexes are able to deliver antitumor drugs (e.g., doxorubicin, paclitaxel, small interfering RNA, and single-stranded DNA) into cancer cells, which enhances the efficacy of treatment. AuNSs can also be functionalized with active targeting ligands such as antibodies, aptamers, and peptides to increase the particles' specific binding to the desired targets. This article reviews the current research on NIR light-activatable AuNSs used as nanocarriers for drug delivery systems and cancer theranostics.

Emerging advances in nanomedicine with engineered gold nanostructures

Gold nanostructures possess unique characteristics that enable their use as contrast agents, as therapeutic entities, and as scaffolds to adhere functional molecules, therapeutic cargo, and targeting ligands. Due to their ease of synthesis, straightforward surface functionalization, and non-toxicity, gold nanostructures have emerged as powerful nanoagents for cancer detection and treatment. This comprehensive review summarizes the progress made in nanomedicine with gold nanostructures (1) as probes for various bioimaging techniques including dark-field, one-photon and two-photon fluorescence, photothermal optical coherence tomography, photoacoustic tomography, positron emission tomography, and surface-enhanced Raman scattering based imaging, (2) as therapeutic components for photothermal therapy, gene and drug delivery, and radiofrequency ablation, and (3) as a theranostic platform to simultaneously achieve both cancer detection and treatment. Distinct from other published reviews, this article also discusses the recent advances of gold nanostructures as contrast agents and therapeutic actuators for inflammatory diseases including atherosclerotic plaque and arthritis. For each of the topics discussed above, the fundamental principles and progress made in the past five years are discussed. The review concludes with a detailed future outlook discussing the challenges in using gold nanostructures, cellular trafficking, and translational considerations that are imperative for rapid clinical viability of plasmonic nanostructures, as well as the significance of emerging technologies such as Fano resonant gold nanostructures in nanomedicine.

Modular plasmonic nanocarriers for efficient and targeted delivery of cancer-therapeutic siRNA

We have combined a versatile and powerful route to deliver nucleic acids with peptide-based cell-specific targeting. siRNA targeting the polo-like kinase gene is in clinical trials for cancer treatment, and here we deliver this RNA selectively to cancer cells displaying the neuropilin-1 epitope using gold nanoshells. Release of the siRNA from the nanoparticles results from irradiation with a pulsed near-infrared laser, which also provides efficient endosomal escape within the cell. As a result, our approach requires 10-fold less material than standard nucleic acid transduction materials and is significantly more efficient than other particle-based methods. We also describe a particle-nucleic acid design that does not rely on modified RNA, thereby making the preparation of these materials more efficient and much less expensive. These improvements, when combined with control over when and where the siRNA is released, could provide the basis for diverse cell biological studies.

Heat generation by irradiated complex composite nanostructures

Heating of irradiated metallic e-beam generated nanostructures was quantified through direct measurements paralleled by novel model-based numerical calculations. By comparing discs, triangles, and stars we showed how particle shape and composition determines the heating. Importantly, our results revealed that substantial heat is generated in the titanium adhesive layer between gold and glass. Even when the Ti layer is as thin as 2 nm it absorbs as much as a 30 nm Au layer and hence should not be ignored.

An integrated microrobotic platform for on-demand, targeted therapeutic interventions

The presented microrobotic platform combines together the advantages of self-folding NIR light sensitive polymer bilayers, magnetic alginate microbeads, and a 3D manipulation system, to propose a solution for targeted, on-demand drug and cell delivery. First feasibility studies are presented together with the potential of the full design.

Quantifying spectral changes experienced by plasmonic nanoparticles in a cellular environment to inform biomedical nanoparticle design

Metal nanoparticles (NPs) scatter and absorb light in precise, designable ways, making them agile candidates for a variety of biomedical applications. When NPs are introduced to a physiological environment and interact with cells, their physicochemical properties can change as proteins adsorb on their surface and they agglomerate within intracellular endosomal vesicles. Since the plasmonic properties of metal NPs are dependent on their geometry and local environment, these physicochemical changes may alter the NPs' plasmonic properties, on which applications such as plasmonic photothermal therapy and photonic gene circuits are based. Here we systematically study and quantify how metal NPs' optical spectra change upon introduction to a cellular environment in which NPs agglomerate within endosomal vesicles. Using darkfield hyperspectral imaging, we measure changes in the peak wavelength, broadening, and distribution of 100-nm spherical gold NPs' optical spectra following introduction to human breast adenocarcinoma Sk-Br-3 cells as a function of NP exposure dose and time. On a cellular level, spectra shift up to 78.6 ± 23.5 nm after 24 h of NP exposure. Importantly, spectra broaden with time, achieving a spectral width of 105.9 ± 11.7 nm at 95% of the spectrum's maximum intensity after 24 h. On an individual intracellular NP cluster (NPC) level, spectra also show significant shifting, broadening, and heterogeneity after 24 h. Cellular transmission electron microscopy (TEM) and electromagnetic simulations of NPCs support the trends in spectral changes we measured. These quantitative data can help guide the design of metal NPs introduced to cellular environments in plasmonic NP-mediated biomedical technologies.

Au-PLA nanocomposites for photothermally controlled drug delivery

Stimuli-responsive drug delivery systems were obtained by encapsulating near-infrared (NIR) sensitive hollow gold nanoshells (HGNs) together with the molecule to be released into biodegradable poly-lactic acid (PLA) sub-micron particles. The rapid heating of the PLA particles caused by NIR radiation enabled use of the PLA-HGN composites as a photo-triggered drug release system. Rhodamine was used as a test molecule to obtain release profiles under different irradiation conditions. HGNs (32 nm diameter, 4.5 nm shell thickness) were synthesized via galvanic replacement of cobalt nanoparticles, using poly(vinylpyrrolidone) (PVP) as a stabilizer. PLA-HGN sub-micron particles (with mean diameters around 200 nm) encapsulating rhodamine were obtained using the supercritical emulsion extraction (SEE) technique. A good gold dispersion and a loading efficiency around 50% in the polymeric matrix were obtained for different HGN loadings. The release rate could be tuned by controlling the intensity of NIR exposition. Rhodamine release was completed in less than 10 hours when applying intense NIR irradiation for a few minutes, whereas 12 days of release was necessary in its absence. The system also allowed rhodamine release in a pulsed pattern.

Plasmonic nanoprobes: from chemical sensing to medical diagnostics and therapy

This article provides an overview of the development and applications of plasmonics-active nanoprobes in our laboratory for chemical sensing, medical diagnostics and therapy. Molecular Sentinel nanoprobes provide a unique tool for DNA/RNA biomarker detection both in a homogeneous solution or on a chip platform for medical diagnostics. The possibility of combining spectral selectivity and high sensitivity of the surface-enhanced Raman scattering (SERS) process with the inherent molecular specificity of nanoprobes provides an important multiplex diagnostic modality. Gold nanostars can provide an excellent multi-modality platform, combining two-photon luminescence with photothermal therapy as well as Raman imaging with photodynamic therapy. Several examples of optical detection using SERS and photonics-based treatments are presented to illustrate the usefulness and potential of the plasmonic nanoprobes for theranostics, which seamlessly combines diagnostics and therapy.

A photo-degradable gene delivery system for enhanced nuclear gene transcription

There currently exists a significant gap in our understanding of how the detailed chemical characteristics of polycation gene carriers influence their delivery performances in overcoming an important cellular-level transport barrier, i.e., intranuclear gene transcription. In this study, a UV-degradable gene carrier material (ENE4-1) was synthesized by crosslinking low molecular weight branched polyethylenimine (bPEI-2k) molecules using UV-cleavable o-nitrobenzyl urethane (NBU) as the linker molecule. NBU degrades upon exposure to mild UV irradiation. Therefore, this UV-degradable carrier allows us to control the chemical characteristics of the polymer/DNA complex (polyplex) particles at desired locations within the intracellular environment. By using this photolytic DNA carrier, we found that the exact timing of the UV degradation significantly influences the gene transfection efficiencies of ENE4-1/DNA(pGL2) polyplexes in HeLa cells. Interestingly, even if the polyplexes were UV-degraded at different intracellular locations/times, their nuclear entry efficiency was not influenced by the location/timing of UV degradation. The UV treatment did not influence the size or binding strength of the polyplexes. However, we confirmed that the degradation of the carrier molecules impacts the chemical characteristics of the polyplexes (it produces carbamic acid and nitrosobenzyl aldehyde groups on ENE4-1). We believe that these anionic acid groups enhance the interaction of the polyplexes with nuclear transcription proteins and thus the final gene expression levels; this effect was found to occur, even though UV irradiation itself has a general effect of reducing transfection efficiencies. Excess (uncomplexed) ENE4-1 polymers appear to not play any role in the UV-enhanced gene transcription phenomenon.

Enhanced photothermal effect of plasmonic nanoparticles coated with reduced graphene oxide

We report plasmonic gold nanoshells and nanorods coated with reduced graphene oxide that produce an enhanced photothermal effect when stimulated by near-infrared (NIR) light. Electrostatic interactions between nanosized graphene oxide and gold nanoparticles followed by in situ chemical reduction generated reduced graphene oxide-coated nanoparticles; the coating was demonstrated using Raman and HR-TEM. Reduced graphene oxide-coated gold nanoparticles showed enhanced photothermal effect compared to noncoated or nonreduced graphene oxide-coated gold nanoparticles. Reduced graphene oxide-coated gold nanoparticles killed cells more rapidly than did noncoated or nonreduced graphene oxide-coated gold nanoparticles.

Selective dehybridization of DNA-Au nanoconjugates using laser irradiation

Plasmonic heating to trigger release of oligonucleotides from nanoconjugates is potentially useful for therapeutic purposes and designed assembly of DNA nanostructures. In the past, great controllability has been achieved by introducing distinctive absorption nanoparticle centers, where the anchoring bond (e.g., sulfur-gold bond) has been selectively broken. Instead of releasing the surface-bound duplex DNA via breakage of the gold-sulphur anchor bond, selective and non-destructive dehybridization of DNA under a "mild" condition on different gold nanoconjugates is demonstrated in this work. This finding will permit sequential dehybridization/release of DNA at specific regions of a complex system; thus it can be extended to control gene expression and to manipulate an assembly of highly organized DNA constructs. Particularly we show herein the feasibility of selectively dehybridizing DNA-Au nanoconjugates via localized plasmonic heating, which is accomplished by controlling the laser wavelength, power, and irradiation time.

Polyethylene glycol and polyethylenimine dual-functionalized nano-graphene oxide for photothermally enhanced gene delivery

Graphene oxide (GO) has been extensively explored in nanomedicine for its excellent physiochemical, electrical, and optical properties. Here, polyethylene glycol (PEG) and polyethylenimine (PEI) are covalently conjugated to GO via amide bonds, obtaining a physiologically stable dual-polymer-functionalized nano-GO conjugate (NGO-PEG-PEI) with ultra-small size. Compared with free PEI and the GO-PEI conjugate without PEGylation, NGO-PEG-PEI shows superior gene transfection efficiency without serum interference, as well as reduced cytotoxicity. Utilizing the NIR optical absorbance of NGO, the cellular uptake of NGO-PEG-PEI is shown to be enhanced under a low power NIR laser irradiation, owing to the mild photothermal heating that increases the cell membrane permeability without significantly damaging cells. As the results, remarkably enhanced plasmid DNA transfection efficiencies induced by the NIR laser are achieved using NGO-PEG-PEI as the light-responsive gene carrier. More importantly, it is shown that our NGO-PEG-PEI is able to deliver small interfering RNA (siRNA) into cells under the control of NIR light, resulting in obvious down-regulation of the target gene, Polo-like kinase 1 (Plk1), in the presence of laser irradiation. This study is the first to use photothermally enhanced intracellular trafficking of nanocarriers for light-controllable gene delivery. This work also encourages further explorations of functionalized nano-GO as a photocontrollable nanovector for combined photothermal and gene therapies.

Localized surface plasmon resonances in spatially dispersive nano-objects: phenomenological treatise

Nonlocal optical response of materials, important at the nanometric scale, influences numerous optical phenomena, such as electromagnetic field confinement and spectral characteristics of plasmonic resonances. Here, we present a general phenomenological approach to account for nonlocal material polarizabilities in nanoscale metal particles. The problem of nonlocal plasmonic resonances is formulated by an integro-differential equation in a space domain and solved by adopting its weak form, implemented in the finite element method, thus, dispensing with the requirements on additional boundary conditions. As an example, nonlocal smearing effects in plasmonic nanorods of various cross sections and nanotubes have been considered. Clear signature of nonlocality manifests itself in the interference fringes in the potential profile and a significant frequency shift of the localized surface plasmon resonances. These effects are especially important for nanoparticles with geometrical features comparable to the de Broglie wavelengths of electrons participating in the light-matter interactions. The proposed method provides a universal tool for phenomenological account of nonlocalities of any kind with the only requirement of linearity in system's response.

HMGB1: A Promising Therapeutic Target for Prostate Cancer

High mobility group box 1 (HMGB1) was originally discovered as a chromatin-binding protein several decades ago. It is now increasingly evident that HMGB1 plays a major role in several disease conditions such as atherosclerosis, diabetes, arthritis, sepsis, and cancer. It is intriguing how deregulation of HMGB1 can result in a myriad of disease conditions. Interestingly, HMGB1 is involved in cell proliferation, angiogenesis, and metastasis during cancer progression. Furthermore, HMGB1 has been demonstrated to exert intracellular and extracellular functions, activating key oncogenic signaling pathways. This paper focuses on the role of HMGB1 in prostate cancer development and highlights the potential of HMGB1 to serve as a key target for prostate cancer treatment.

Silver nanoscale antisense drug delivery system for photoactivated gene silencing

The unique photophysical properties of noble metal nanoparticles contribute to their potential as photoactivated drug delivery vectors. Here we demonstrate the synthesis and characterization of 60-80 nm silver nanoparticles (SNPs) decorated with thiol-terminated photolabile DNA oligonucleotides. In vitro assays and fluorescent confocal microscopy of treated cell cultures show efficient UV-wavelength photoactivation of surface-tethered caged ISIS2302 antisense oligonucleotides possessing internal photocleavable linkers. As a demonstration of the advantages of these novel nanocarriers, we investigate properties including: enhanced stability to nucleases, increased hybridization activity upon photorelease, and efficient cellular uptake as compared to commercial transfection vectors. Their potential as multicomponent delivery agents for oligonucleotide therapeutics is shown through regulation of ICAM-1 (Intracellular Adhesion Molecule-1) silencing. Our results suggest a means to achieve light-triggered, spatiotemporally controlled gene silencing via nontoxic silver nanocarriers, which hold promise as tailorable platforms for nanomedicine, gene expression studies, and genetic therapies.

Theranostic agents for intracellular gene delivery with spatiotemporal imaging

Gene therapy is the modification of gene expression to treat a disease. However, efficient intracellular delivery and monitoring of gene therapeutic agents is an ongoing challenge. Use of theranostic agents with suitable targeted, controlled delivery and imaging modalities has the potential to greatly advance gene therapy. Inorganic nanoparticles including magnetic nanoparticles, gold nanoparticles, and quantum dots have been shown to be effective theranostic agents for the delivery and spatiotemporal tracking of oligonucleotides in vitro and even a few cases in vivo. Major concerns remain to be addressed including cytotoxicity, particularly of quantum dots; effective dosage of nanoparticles for optimal theranostic effect; development of real-time in vivo imaging; and further improvement of gene therapy efficacy.

Nanomaterials as Non-viral siRNA Delivery Agents for Cancer Therapy

Gene therapy has been recently shown as a promising tool for cancer treatment as nanotechnology-based safe and effective delivery methods are developed. Generally, genes are wrapped up in extremely tiny nanoparticles which could be taken up easily by cancer cells, not to their healthy neighboring cells. Several nanoparticle systems have been investigated primarily to address the problems involved in other methods of gene delivery and observed improved anticancer efficacy suggesting that nanomedicine provides novel opportunities to safely deliver genes, thus treat cancer. In this review, various nanoparticle types and related strategies, used in gene delivery for cancer treatment, have been discussed.

YB-1: oncoprotein, prognostic marker and therapeutic target?

Hanahan and Weinberg have proposed the ‘hallmarks of cancer’ to cover the biological changes required for the development and persistence of tumours [Hanahan and Weinberg (2011) Cell 144, 646–674]. We have noted that many of these cancer hallmarks are facilitated by the multifunctional protein YB-1 (Y-box-binding protein 1). In the present review we evaluate the literature and show how YB-1 modulates/regulates cellular signalling pathways within each of these hallmarks. For example, we describe how YB-1 regulates multiple proliferation pathways, overrides cell-cycle check points, promotes replicative immortality and genomic instability, may regulate angiogenesis, has a role in invasion and metastasis, and promotes inflammation. We also argue that there is strong and sufficient evidence to suggest that YB-1 is an excellent molecular marker of cancer progression that could be used in the clinic, and that YB-1 could be a useful target for cancer therapy.