Emerging implications of nanotechnology on cancer diagnostics and therapeutics

Encapsulating Ionic Liquid and Fe₃O₄ Nanoparticles in Gelatin Microcapsules as Microwave Susceptible Agent for MR Imaging-guided Tumor Thermotherapy

The combination of therapies and monitoring the treatment process has become a new concept in cancer therapy. Herein, gelatin-based microcapsules have been first reported to be used as microwave (MW) susceptible agent and magnetic resonance (MR) imaging contrast agent for cancer MW thermotherapy. Using the simple coacervation methods, ionic liquid (IL) and Fe3O4 nanoparticles (NPs) were wrapped in microcapsules, and these microcapsules showed good heating efficacy in vitro under MW irradiation. The results of cell tests indicated that gelatin/IL@Fe3O4 microcapsules possessed excellent compatibility in physiological environments, and they could effectively kill cancer cells with exposure to MW. The ICR mice bearing H22 tumors treated with gelatin/IL@Fe3O4 microcapsules were obtained an outstanding MW thermotherapy efficacy with 100% tumor elimination under ultralow density irradiation (1.8 W/cm(2), 450 MHz). In addition, the applicability of the microcapsules as an efficient contrast agent for MR imaging in vivo was evident. Therefore, these multifunctional microcapsules have a great potential for MR imaging-guided MW thermotherapy.

Optically modulated cancer therapeutic delivery: past, present and future

Chemotherapeutic regimens are often restricted by dose-limiting toxicities that arise from drug exposure to off-site tissues. Nanoparticle drug carriers that specifically deliver therapeutics to the site of malignant tissue are being actively researched today. One strategy is to utilize materials that are light-responsive, such that the carrier can be triggered to release its drug payload at the distinct time and location of light exposure. This review discusses recent advances in the development of such light-responsive drug carriers. With continued optimization and in vivo validation, these approaches may offer novel treatment options for cancer management.

Coating Solid Lipid Nanoparticles with Hyaluronic Acid Enhances Antitumor Activity against Melanoma Stem-like Cells

Successful anticancer chemotherapy requires targeting tumors efficiently and further potential to eliminate cancer stem cell (CSC) subpopulations. Since CD44 is present on many types of CSCs, and it binds specially to hyaluronic acid (HA), we tested whether coating solid lipid nanoparticles with hyaluronan (HA-SLNs)would allow targeted delivery of paclitaxel (PTX) to CD44-overexpressing B16F10 melanoma cells. First, we developed a model system based on melanoma stem-like cells for experiments in vitro and in mouse xenografts, and we showed that cells expressing high levels of CD44 (CD44⁺) displayed a strong CSC phenotype while cells expressing low levels of CD44 (CD44^-) did not. This phenotype included sphere and colony formation, higher proportion of side population cells, expression of CSC-related markers (ALDH, CD133, Oct-4) and tumorigenicity in vivo. Next we showed that administering PTX-loaded HA-SLNs led to efficient intracellular delivery of PTX and induced substantial apoptosis in CD44⁺ cells in vitro. In the B16F10-CD44⁺ lung metastasis model, PTX-loaded HA-SLNs targeted the tumor-bearing lung tissues well and subsequently exhibited significant antitumor effects with a relative low dose of PTX, which provided significant survival benefit without evidence of adverse events. These findings suggest that the HA-SLNs targeting system shows promise for enhancing cancer therapy.

Effect of diameter of nanoparticles and capture cross-section library on macroscopic dose enhancement in boron neutron capture therapy

Purpose

The aim of this study is evaluation of the effect of diameter of ¹⁰B nanoparticles and various neutron capture cross-section libraries on macroscopic dose enhancement in boron neutron capture therapy (BNCT).

Material and methods

MCNPX Monte Carlo code was used for simulation of a ²⁵²Cf source, a soft tissue phantom and a tumor containing ¹⁰B nanoparticles. Using ²⁵²Cf as a neutron source, macroscopic dose enhancement factor (MDEF) and total dose rate in tumor in the presence of 100, 200, and 500 ppm of ¹⁰B nanoparticles with 25 nm, 50 nm, and 100 nm diameters were calculated. Additionally, the effect of ENDF, JEFF, JENDL, and CENDL neutron capture cross-section libraries on MDEF was evaluated.

Results

There is not a linear relationship between the average MDEF value and nanoparticles’ diameter but the average MDEF grows with increased concentration of ¹⁰B nanoparticles. There is an increasing trend for average MDEF with the tumor distance. The average MDEF values were obtained the same for various neutron capture cross-section libraries. The maximum and minimum doses that effect on the total dose in tumor were neutron and secondary photon doses, respectively. Furthermore, the boron capture related dose component reduced in some extent with increase of diameter of ¹⁰B nanoparticles.

Conclusions

Based on the results of this study, it can be concluded that from physical point of view, various nanoparticle diameters have no dominant effect on average MDEF value in tumor. Furthermore, it is concluded that various neutron capture cross-section libraries are resulted to the same macroscopic dose enhancements. However, it is predicted that taking into account the biological effects for various nanoparticle diameters will result in different dose enhancements.

Quantum dots-based tissue and in vivo imaging in breast cancer researches: current status and future perspectives

As the most common malignant tumor for females, breast cancer (BC) is a highly heterogeneous disease regarding biological behaviors. Precisely targeted imaging on BC masses and biomarkers is critical to BC detection, treatment, monitoring, and prognostic evaluation. As an important imaging technique, quantum dots (QDs)-based imaging has emerged as a promising tool in BC researches owe to its outstanding optical properties. However, few reviews have been specifically devoted to discussing applications of QDs-based imaging in BC researches. This review summarized recent promising works in QDs-based tissue and in vivo imaging for BC studies. Physicochemical and optical properties of QDs and its potential applications were briefly described first. Then QDs-based imaging studies in BC were systematically reviewed, including tissue imaging for studying biomarkers interactions, and evaluating prognostic biomarkers, in vivo imaging for mapping axillary lymphatic system, showing BC xenograft tumor, and detecting BC metastases. At last, the future perspectives with special emphasis on the potential clinical applications have also been discussed. Potential applications of QDs-based imaging on clinical BC in the future are mainly focused on tissue study, especially in BC molecular pathology due to its optimal optical properties and quantitative information capabilities on multiple biomarkers.

Supramolecular nanostructures based on bacterial reaction center proteins and quantum dots

Design of the nanostructures based on membrane proteins (the key functional elements of biomembranes) and colloid nanoparticles is a fascinating field at the interface of biochemistry and colloids, nanotechnology and biomedicine. The review discusses the main achievements in the field of ultrathin films prepared from bacterial reaction center proteins and light-harvesting complexes, as well as these complexes tagged with quantum dots. The principles of preparation of these thin films and their structure and properties at different interfaces are described; as well as their characteristics estimated using a combination of the modern interfacial techniques (absorption and fluorescence spectroscopy, atomic force and Brewster angle microscopy, etc.) are discussed. Further approaches to develop the nanostructures based on the membrane proteins and quantum dots are suggested. These supramolecular nanostructures are promising prototypes of the materials for photovoltaic, optoelectronic and biosensing applications.

Biodistribution and in vivo toxicity of aptamer-loaded gold nanostars

This paper reports an in vivo evaluation of toxicology and biodistribution of a highly anisotropic Au nanoconstruct composed of a gold nanostar (AuNS) core and a ligand shell of a G-quadruplex DNA aptamer AS1411 (Apt) supporting both targeting and therapy capabilities. We examined the toxicity of the nanoconstructs (Apt-AuNS) at four different injected concentrations. At the highest dose tested (48 mg/kg), maximal tolerated dose was not reached. Clinical pathology showed no apparent signs of acute toxicity. Interestingly, the nanoconstructs circulated longer in female rats compared to male rats. In two different tumor models, the biodistribution of Apt-AuNS, especially tumor accumulation, was different. Accumulation of Apt-AuNS was 5 times higher in invasive breast cancer tumors compared to fibrosarcoma tumors. These results provide insight on identifying a tumor model and nanoconstruct for in vivo studies, especially when an in vitro therapeutic response is observed in multiple cancer cell lines. From the clinical editor: This study investigated the toxicity and distribution of aptamer loaded gold nanostars in a rodent model of invasive breast cancer and fibrosarcoma. Acute toxicity was not identified even in the highest studied doses. Fivefold accumulation was demonstrated in the breast cancer model compared to the fibrosarcoma model. Studies like this are critically important in further clarifying the potential therapeutic use of these nanoconstructs, especially when ex vivo effects are clearly demonstrated.

Gelatin microcapsules for enhanced microwave tumor hyperthermia

Local and rapid heating by microwave (MW) irradiation is important in the clinical treatment of tumors using hyperthermia. We report here a new thermo-seed technique for the highly efficient MW irradiation ablation of tumors in vivo based on gelatin microcapsules. We achieved 100% tumor elimination in a mouse model at an ultralow power of 1.8 W without any side-effects. The results of MTT assays, a hemolysis test and the histological staining of organs indicated that the gelatin microcapsules showed excellent compatibility with the physiological environment. A possible mechanism is proposed for MW hyperthermia using gelatin microcapsules. We also used gelatin microcapsules capped with CdTe quantum dots for in vivo optical imaging. Our study suggests that these microcapsules may have potential applications in imaging-guided cancer treatment.

Nanomaterials for boron and gadolinium neutron capture therapy for cancer treatment

Cancer is one of the leading causes of death; with it may different types, it kills thousands of people every day. Various types of treatment have been developed to treat and cure cancer. Nanotechnology has emerged as one of the most fruitful areas of science in cancer treatment and the nanomaterials are considered as a medical boon for the diagnosis, treatment and prevention of cancer. The major approaches of nanotechnology in tumor treatment include the development of nanoparticles with less or no tissue-resistance, their biocompatibility, ability as nanocarriers for drug delivery, and enhanced energy deposition in tissue with or without the external influence of microwave, light, magnet, etc. This review presents some of the recent developments in the use of nanoparticles as adjuncts to boron and gadolinium containing compounds in boron neutron capture therapy (BNCT) and gadolinium neutron capture therapy (GdNCT) along with the latest developments in the area of boron nanotubes (BNTs), gadolinium oxide, boron nitride nanotubes (BNNTs) and the boron agent itself.

Killing cancer cells by delivering a nanoreactor for inhibition of catalase and catalytically enhancing intracellular levels of ROS

Intracellular hydrogen peroxide levels have the potential to be exploited in cancer therapy.

Elucidating the Uptake and Distribution of Nanoparticles in Solid Tumors via a Multilayered Cell Culture Model

Multicellular layers (MCLs) have previously been used to determine the pharmacokinetics of a variety of different cancer drugs including paclitaxel, doxorubicin, methotrexate, and 5-fluorouracil across a number of cell lines. It is not known how nanoparticles (NPs) navigate through the tumor microenvironment once they leave the tumor blood vessel. In this study, we used the MCL model to study the uptake and penetration dynamics of NPs. Gold nanoparticles (GNPs) were used as a model system to map the NP distribution within tissue-like structures. Our results show that NP uptake and transport are dependent on the tumor cell type. MDA-MB-231 tissue showed deeper penetration of GNPs as compared to MCF-7 one. Intracellular and extracellular distributions of NPs were mapped using CytoViva imaging. The ability of MCLs to mimic tumor tissue characteristics makes them a useful tool in assessing the efficacy of particle distribution in solid tumors.

Advances in the application of nanotechnology in the diagnosis and treatment of gastrointestinal tumors

Nanotechnology has broad application prospects in the diagnosis and treatment of cancer. Integrating chemistry, engineering, biology and medicine, nanotechnology is a multidisciplinary research field. Nanoscale imaging technology significantly improves the precision and accuracy of tumor diagnosis. Nanocarriers are able to significantly improve the accuracy of dose and targeted drug delivery and reduce the toxic side effects. This review focuses on the emerging roles of these innovative technologies in gastrointestinal cancer diagnostics and therapeutics. Although several problems and barriers are hampering the development of nanodevices, the potential for nanotechnologies to function as multimodal nanotheranostic agents will likely pave the way for the fight against gastrointestinal cancer.

Peptide modified gold nanoparticles for improved cellular uptake, nuclear transport, and intracellular retention

Gold nanoparticles (GNPs) are being extensively used in cancer therapeutic applications due to their ability to act both as an anticancer drug carrier in chemotherapy and as a dose enhancer in radiotherapy. The therapeutic response can be further enhanced if nanoparticles (NPs) can be effectively targeted into the nucleus. Here, we present an uptake and removal of GNPs functionalized with three peptides. The first peptide (RGD peptide) enhanced the uptake, the second peptide (NLS peptide) facilitated the nuclear delivery, while the third one (pentapeptide) covered the rest of the surface and protected it from the binding of serum proteins onto the NP surface. The pentapeptide also stabilized the conjugated GNP complex. The peptide-capped GNPs showed a five-fold increase in NP uptake followed by effective nuclear localization. The fraction of NPs exocytosed was less for peptide-capped NPs as compared to citrate-capped ones. Enhanced uptake and prolonged intracellular retention of peptide-capped GNPs could allow NPs to perform their desired applications more efficiently in cells. These studies will provide guidelines for developing NPs for therapeutic applications, which will require "controlling" of the NP accumulation rate while maintaining low toxicity.

Potential nanotechnologies and molecular targets in the quest for efficient chemotherapy in ovarian cancer

INTRODUCTION

Ovarian cancer, considered one of the most fatal gynecological cancers, goes largely undiagnosed until metastasis presents itself, usually once the patient is in the final stages and thus, too late for worthwhile therapy. Targeting this elusive disease in its early stages would improve the outcome for most patients, while the information generated thereof would increase the possibility of preventative mechanisms of therapy.

AREAS COVERED

This review discusses various molecular targets as possible moieties to be incorporated in a holistic drug delivery system or the more aptly termed 'theranostic' system. These molecular targets can be used for targeting, visualizing, diagnosing, and ultimately, treating ovarian cancer in its entirety. Currently implemented nanoframeworks, such as nanomicelles and nanoliposomes, are described and the effectiveness of nanostructures in tumor targeting, treatment functions, and overcoming the drug resistance challenge is discussed.

EXPERT OPINION

Novel nanotechnology strategies such as the development of nanoframeworks decorated with targeted ligands of a molecular nature may provide an efficient chemotherapy, especially when instituted in combination with imaging, diagnostic, and ultimately, therapeutic moieties. An imperative aspect of utilizing nanotechnology in the treatment of ovarian cancer is the flexibility of the drug delivery system and its ability to overcome standard obstacles such as: i) successfully treating the desired cells through direct targeting; ii) reducing toxicity levels of treatment by achieving direct targeting; and iii) delivery of targeted therapy using an efficient vehicle that is exceptionally degradable in response to a particular stimulus. The targeting of ovarian cancer in its early stages using imaging and diagnostic nanotechnology is an area that can be improved upon by combining therapeutic moieties with molecular biomarkers. The nanotechnology and molecular markers mentioned in this review have generally been used for either imaging or diagnostics, and have not yet been successfully implemented into bi-functional tools, which it is hoped, should eventually include a therapeutic aspect.

Spectroscopic investigations, antimicrobial, and cytotoxic activity of green synthesized gold nanoparticles

The gold nanoparticles (AuNPs) were synthesized by using naturally available Punica Granatum fruit extract as reducing and stabilizing agent. The biosynthesized AuNPs was characterized by using UV-Vis, fluorescence, high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric (TGA) analysis. The surface plasmon resonance (SPR) band at 585nm confirmed the reduction of auric chloride to AuNPs. The crystalline nature of the biosynthesized AuNPs was confirmed from the HRTEM images, XRD and selected area electron diffraction (SAED) pattern. The HRTEM images showed the mixture of triangular and spherical-like AuNPs having size between 5 and 20nm. The weight loss of the AuNPs was measured by TGA as a function of temperature under a controlled atmosphere. The biomolecules are responsible for the reduction of AuCl4(-) ions and the formation of stable AuNPs which was confirmed by FTIR measurement. The synthesized AuNPs showed an excellent antibacterial activity against Candida albicans (ATCC 90028), Aspergillus flavus (ATCC 10124), Staphylococcus aureus (ATCC 25175), Salmonella typhi (ATCC 14028) and Vibrio cholerae (ATCC 14033). The minimum inhibitory concentration (MIC) of AuNPs was recorded against various microorganisms. Further, the synthesized AuNPs shows an excellent cytotoxic result against HeLa cancer cell lines at different concentrations.

EGFR-targeted plasmonic magnetic nanoparticles suppress lung tumor growth by abrogating G2/M cell-cycle arrest and inducing DNA damage

Background

We have previously demonstrated the epidermal growth factor receptor (EGFR)-targeted hybrid plasmonic magnetic nanoparticles (225-NP) produce a therapeutic effect in human lung cancer cell lines in vitro. In the present study, we investigated the molecular mechanism of 225-NP-mediated antitumor activity both in vitro and in vivo using the EGFR-mutant HCC827 cell line.

Methods

The growth inhibitory effect of 225-NP on lung tumor cells was determined by cell viability and cell-cycle analysis. Protein expression related to autophagy, apoptosis, and DNA-damage were determined by Western blotting and immunofluorescence. An in vivo efficacy study was conducted using a human lung tumor xenograft mouse model.

Results

The 225-NP treatment markedly reduced tumor cell viability at 72 hours compared with the cell viability in control treatment groups. Cell-cycle analysis showed the percentage of cells in the G2/M phase was reduced when treated with 225-NP, with a concomitant increase in the number of cells in Sub-G1 phase, indicative of cell death. Western blotting showed LC3B and PARP cleavage, indicating 225-NP-treatment activated both autophagy- and apoptosis-mediated cell death. The 225-NP strongly induced γH2AX and phosphorylated histone H3, markers indicative of DNA damage and mitosis, respectively. Additionally, significant γH2AX foci formation was observed in 225-NP-treated cells compared with control treatment groups, suggesting 225-NP induced cell death by triggering DNA damage. The 225-NP-mediated DNA damage involved abrogation of the G2/M checkpoint by inhibiting BRCA1, Chk1, and phospho-Cdc2/CDK1 protein expression. In vivo therapy studies showed 225-NP treatment reduced EGFR phosphorylation, increased γH2AX foci, and induced tumor cell apoptosis, resulting in suppression of tumor growth.

Conclusion

The 225-NP treatment induces DNA damage and abrogates G2/M phase of the cell cycle, leading to cellular apoptosis and suppression of lung tumor growth both in vitro and in vivo. Our findings provide a rationale for combining 225-NP with other DNA-damaging agents for achieving enhanced anticancer activity.

Stepwise encapsulation and controlled two-stage release system for cis-Diamminediiodoplatinum

cis-Diamminediiodoplatinum (cis-DIDP) is a cisplatin-like anticancer drug with higher anticancer activity, but lower stability and price than cisplatin. In this study, a cis-DIDP carrier system based on micro-sized stearic acid was prepared by an emulsion solvent evaporation method. The maximum drug loading capacity of cis-DIDP-loaded solid lipid nanoparticles was 22.03%, and their encapsulation efficiency was 97.24%. In vitro drug release in phosphate-buffered saline (pH =7.4) at 37.5°C exhibited a unique two-stage process, which could prove beneficial for patients with tumors and malignancies. MTT (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) assay results showed that cis-DIDP released from cis-DIDP-loaded solid lipid nanoparticles had better inhibition activity than cis-DIDP that had not been loaded.

Radiation dose enhancement of gadolinium-based AGuIX nanoparticles on HeLa cells

Radiation dose enhancement of high-Z nanoparticles is an active area of research in cancer therapeutics. When kV and MV energy photon beams interact with high-Z nanoparticles in a tumor, the release of secondary electrons can injure tumor cells, leading to a higher treatment efficacy than radiation alone. We present a study that characterizes the radiation dose enhancing effects of gadolinium-based AGuIX nanoparticles on HeLa cells. Our in vitro clonogenic survival assays showed an average dose enhancement of 1.54× for 220 kVp radiation and 1.15× for 6 MV radiation. The sensitivity enhancement ratio at 4 Gy (SER4Gy) was 1.54 for 220 kVp and 1.28 for 6 MV, indicating that these nanoparticles may be useful for clinical radiation therapy.

FROM THE CLINICAL EDITOR

This study characterized the radiation dose enhancing effects of gadolinium-based AGuIX nanoparticles on HeLa cells, showing clear effects at 220 kV as well as 6 MV, suggesting that after additional studies, these nanoparticles may be beneficial in human radiation therapy.

Evaluation of nanolipoprotein particles (NLPs) as an in vivo delivery platform

Nanoparticles hold great promise for the delivery of therapeutics, yet limitations remain with regards to the use of these nanosystems for efficient long-lasting targeted delivery of therapeutics, including imparting functionality to the platform, in vivo stability, drug entrapment efficiency and toxicity. To begin to address these limitations, we evaluated the functionality, stability, cytotoxicity, toxicity, immunogenicity and in vivo biodistribution of nanolipoprotein particles (NLPs), which are mimetics of naturally occurring high-density lipoproteins (HDLs). We found that a wide range of molecules could be reliably conjugated to the NLP, including proteins, single-stranded DNA, and small molecules. The NLP was also found to be relatively stable in complex biological fluids and displayed no cytotoxicity in vitro at doses as high as 320 µg/ml. In addition, we observed that in vivo administration of the NLP daily for 14 consecutive days did not induce significant weight loss or result in lesions on excised organs. Furthermore, the NLPs did not display overt immunogenicity with respect to antibody generation. Finally, the biodistribution of the NLP in vivo was found to be highly dependent on the route of administration, where intranasal administration resulted in prolonged retention in the lung tissue. Although only a select number of NLP compositions were evaluated, the findings of this study suggest that the NLP platform holds promise for use as both a targeted and non-targeted in vivo delivery vehicle for a range of therapeutics.

Dynamic light scattering on bioconjugated laser generated gold nanoparticles

Gold nanoparticles (AuNPs) conjugated to DNA are widely used for biomedical targeting and sensing applications. DNA functionalization is easily reached on laser generated gold nanoparticles because of their unique surface chemistry, not reproducible by other methods. In this context, we present an extensive investigation concerning the attachment of DNA to the surface of laser generated nanoparticles using Dynamic Light Scattering and UV-Vis spectroscopy. The DNA conjugation is highlighted by the increase of the hydrodynamic radius and by the UV-Vis spectra behavior. Our investigation indicates that Dynamic Light Scattering is a suitable analytical tool to evidence, directly and qualitatively, the binding between a DNA molecule and a gold nanoparticle, therefore it is ideal to monitor changes in the conjugation process when experimental conditions are varied.

Nanobiosensors: role in cancer detection and diagnosis

The ability to detect many cancers at an early stage in its clinical course has the potential to improve patient outcomes in terms of morbidity and mortality. Nanosized components incorporated into existing clinical diagnostic and detection systems as well as novel nanobiosensors have demonstrated improved sensitivity and specificity compared with traditional cancer testing approaches. Nanoparticles, nanowires, nanotubes, and nanocantilevers are examples of four nanobiosensor systems that have been used experimentally in the context of detection and diagnosis of prostate, breast, pancreatic, lung, and brain cancers over the past few years. Nanobiosensors will begin to transition into clinically validated tests as experimental and engineering techniques advance. This paper presents examples of some such nanobiosensors for cancer diagnosis and detection.

Applications and perspectives of boron-enriched nanocomposites in cancer therapy

Recently, boron compounds have attracted increasing attention both in academic laboratories and in the pharmaceutical industry. Boron, in particular the (10)B isotope, has the unique capability of absorbing a slow neutron to initiate a nuclear reaction with release of energetic particles such as α- and Li-particles, which is not observed in its carbon analogues. The nuclear capture reaction concept has been adopted in radiation therapy and used in boron neutron capture therapy (BNCT). BNCT is a potentially promising treatment for malignant brain tumors as well as other cancers, despite the limitation of a scarcity of neutron sources. There is the need in advanced research centers to construct high boron-containing composites as BNCT agents and develop more efficient drug carriers. This review discusses recent works on the development of boron-based therapeutic nanomaterials as BNCT agents.

Proper design of silica nanoparticles combines high brightness, lack of cytotoxicity and efficient cell endocytosis

Silica-based luminescent nanoparticles (SiNPs) show promising prospects in nanomedicine in light of their chemical properties and versatility. In this study, we have characterized silica core-PEG shell SiNPs derivatized with PEG moieties (NP-PEG), with external amino- (NP-PEG-amino) or carboxy-groups (NP-PEG-carbo), both in cell cultures as well as in animal models. By using different techniques, we could demonstrate that these SiNPs were safe and did not exhibit appreciable cytotoxicity in different relevant cell models, of normal or cancer cell types, growing either in suspension (JVM-2 leukemic cell line and primary normal peripheral blood mononuclear cells) or in adherence (human hepatocarcinoma Huh7 and umbilical vein endothelial cells). Moreover, by multiparametric flow cytometry, we could demonstrate that the highest efficiency of cell uptake and entry was observed with NP-PEG-amino, with a stable persistence of the fluorescence signal associated with SiNPs in the loaded cell populations both in vitro and in vivo settings suggesting this as an innovative method for cell traceability and detection in whole organisms. Finally, experiments performed with the endocytosis inhibitor Genistein clearly suggested the involvement of a caveolae-mediated pathway in SiNP endocytosis. Overall, these data support the safe use of these SiNPs for diagnostic and therapeutic applications.

Membrane mimetic surface functionalization of nanoparticles: methods and applications

Nanoparticles (NPs), due to their size-dependent physical and chemical properties, have shown remarkable potential for a wide range of applications over the past decades. Particularly, the biological compatibilities and functions of NPs have been extensively studied for expanding their potential in areas of biomedical application such as bioimaging, biosensing, and drug delivery. In doing so, surface functionalization of NPs by introducing synthetic ligands and/or natural biomolecules has become a critical component in regard to the overall performance of the NP system for its intended use. Among known examples of surface functionalization, the construction of an artificial cell membrane structure, based on phospholipids, has proven effective in enhancing biocompatibility and has become a viable alternative to more traditional modifications, such as direct polymer conjugation. Furthermore, certain bioactive molecules can be immobilized onto the surface of phospholipid platforms to generate displays more reminiscent of cellular surface components. Thus, NPs with membrane-mimetic displays have found use in a range of bioimaging, biosensing, and drug delivery applications. This review herein describes recent advances in the preparations and characterization of integrated functional NPs covered by artificial cell membrane structures and their use in various biomedical applications.

A novel mycotoxin purification system using magnetic nanoparticles for the recovery of aflatoxin B1 and zearalenone from feed

In this study, we developed a novel tool for purifying two mycotoxins, aflatoxin B1 (AFB1) and zearalenone (ZEN), in feed. This system utilized monoclonal antibodies (mAbs) against AFB1 and ZEN, and magnetic nanoparticles (MNPs). Among ten MNPs with different diameters and functional groups, a 100-nm diameter MNP (fMA) conjugated to an amine group (-NH₂) was found to be optimum for coupling with mAbs. The optimal mAb concentrations for coupling to the fMA along with mycotoxin purification capacities of the fMA-mAb conjugates (fMA-AFB1 and fMA-ZEN) were determined. A comparison of mean recovery rates (from corn and product X feed) between the fMA-mAb conjugates and immunoaffinity columns (IAC-AFB1 and IAC-ZEN) showed that the rate for fMA-AFB1 (90~92% and 81~88%) was higher (p > 0.05) than that of IAC-AFB1 (81~84% and 72~78%) for AFB1 (5, 10, 15 ng/mL), and the rate for fMA-ZEN (99~100% and 92~94%) was significantly higher (p < 0.01) than that of IAC-ZEN (86~88% and 81~88%) for ZEN (10, 25, 50 ng/mL) except at a concentration of 10 ng/mL, demonstrating the remarkable purification efficiency of the novel fMA-mAb method. Additionally, mycotoxin purification was much faster using our novel method (approx. 5 min) than the IAC-based technique (> 30 min). This study suggests that the novel purification system we developed would be a useful tool for monitoring and regulating mycotoxin contamination in feed, and replace IAC methods.

HREM analysis of graphite-encapsulated metallic nanoparticles for possible medical applications

High resolution electron microscopy has been applied to study the structure of metallic nanoparticles. These have sparked considerable interest as contrast agents in the field of biological imaging, including in magnetic resonance imaging (MRI) and computed tomography (CT). Here, we describe a method of synthesizing sub-10nm superparamagnetic metal and alloy nanoparticles by reduction of metallic salts. Annealing at 900°C in a methane/hydrogen environment forms a thin graphitic-carbon shell which is expected to improve stability, biocompatibility, and functionalization. Subsequent high resolution electron microscopy verifies graphitization and allows for crystallographic analysis. Most particles consist of single crystals in the phase predicted for the bulk material at the annealing temperature. Electron energy loss spectroscopy, energy dispersive X-ray spectroscopy and lattice constant measurements show large variation in composition for alloy nanoparticles from a single synthesis. The magnetization relaxation time (T2) measurements demonstrate that Fe and AuFe nanoparticles compete with commercially available iron oxide MRI contrast agents. X-ray attenuation measurements of an AuFe alloy nanoparticle solution gave a relative radiodensity of 280 Hounsfield Units, demonstrating promise as a dual-purpose contrast agent in CT and MRI. Long term stability in an atmospheric environment was also tested, with no signs of corrosion or oxidation after several years of storage.

Thiomers: promising platform for macromolecular drug delivery

The application of macromolecules as therapeutic agents holds great promise for several major disorders such as cancer and cardiovascular disease. However, their use is limited by the lack of efficient, safe and specific delivery strategies. A promising strategy to overcome these challenges might be the use of thiolated polymers or designated thiomers. Thiomers are synthesized by immobilization of sulfhydryl bearing ligands on a polymeric backbone of well-established polymers. These multifunctional polymeric excipients show advantages in mucoadhesion, enzyme and efflux pump inhibition in comparison to unmodified polymers. One obstacle in the use of thiomers is that they are prone to oxidation at lower pH but this could be solved by introducing a completely new generation of thiomers, namely, the preactivated thiomer generation. Preactivated thiomers are mixed disulfides, which exhibit oxidation resistance and, beyond that, improved thiomer features. This review summarizes recent findings of polymeric excipients for macromolecular drug delivery as well as their synthesis and distinctive features.

A top-down synthesis route to ultrasmall multifunctional Gd-based silica nanoparticles for theranostic applications

New, ultrasmall nanoparticles with sizes below 5 nm have been obtained. These small rigid platforms (SRP) are composed of a polysiloxane matrix with DOTAGA (1,4,7,10-tetraazacyclododecane-1-glutaric anhydride-4,7,10-triacetic acid)-Gd(3+) chelates on their surface. They have been synthesised by an original top-down process: 1) formation of a gadolinium oxide Gd2O3 core, 2) encapsulation in a polysiloxane shell grafted with DOTAGA ligands, 3) dissolution of the gadolinium oxide core due to chelation of Gd(3+) by DOTAGA ligands and 4) polysiloxane fragmentation. These nanoparticles have been fully characterised using photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), a superconducting quantum interference device (SQUID) and electron paramagnetic resonance (EPR) to demonstrate the dissolution of the oxide core and by inductively coupled plasma mass spectrometry (ICP-MS), mass spectrometry, fluorescence spectroscopy, (29)Si solid-state NMR, (1)H NMR and diffusion ordered spectroscopy (DOSY) to determine the nanoparticle composition. Relaxivity measurements gave a longitudinal relaxivity r1 of 11.9 s(-1)  mM(-1) per Gd at 60 MHz. Finally, potentiometric titrations showed that Gd(3+) is strongly chelated to DOTAGA (complexation constant logβ110 =24.78) and cellular tests confirmed the that nanoconstructs had a very low toxicity. Moreover, SRPs are excreted from the body by renal clearance. Their efficiency as contrast agents for MRI has been proved and they are promising candidates as sensitising agents for image-guided radiotherapy.

Magnetic field activated lipid-polymer hybrid nanoparticles for stimuli-responsive drug release

Stimuli-responsive nanoparticles (SRNPs) offer the potential of enhancing the therapeutic efficacy and minimizing the side-effects of chemotherapeutics by controllably releasing the encapsulated drug at the target site. Currently controlled drug release through external activation remains a major challenge during the delivery of therapeutic agents. Here we report a lipid-polymer hybrid nanoparticle system containing magnetic beads for stimuli-responsive drug release using a remote radio frequency (RF) magnetic field. These hybrid nanoparticles show long-term stability in terms of particle size and polydispersity index in phosphate-buffered saline (PBS). Controllable loading of camptothecin (CPT) and Fe(3)O(4) in the hybrid nanoparticles was demonstrated. RF-controlled drug release from these nanoparticles was observed. In addition, cellular uptake of the SRNPs into MT2 mouse breast cancer cells was examined. Using CPT as a model anticancer drug the nanoparticles showed a significant reduction in MT2 mouse breast cancer cell growth in vitro in the presence of a remote RF field. The ease of preparation, stability, and controllable drug release are the strengths of the platform and provide the opportunity to improve cancer chemotherapy.

Nanoparticle translocation across mouse alveolar epithelial cell monolayers: species-specific mechanisms

Studies of polystyrene nanoparticle (PNP) trafficking across mouse alveolar epithelial cell monolayers (MAECM) show apical-to-basolateral flux of 20 and 120nm amidine-modified PNP is ~65 times faster than that of 20 and 100nm carboxylate-modified PNP, respectively. Calcium chelation with EGTA has little effect on amidine-modified PNP flux, but increases carboxylate-modified PNP flux ~50-fold. PNP flux is unaffected by methyl-β-cyclodextrin, while ~70% decrease in amidine- (but not carboxylate-) modified PNP flux occurs across chlorpromazine- or dynasore-treated MAECM. Confocal microscopy reveals intracellular amidine- and carboxylate-modified PNP and association of amidine- (but not carboxylate-) modified PNP with clathrin heavy chain. These data indicate (1) amidine-modified PNP translocate across MAECM primarily via clathrin-mediated endocytosis and (2) physicochemical properties (e.g., surface charge) determine PNP interactions with mouse alveolar epithelium. Uptake/trafficking of nanoparticles into/across epithelial barriers is dependent on both nanoparticle physicochemical properties and (based on comparison with our prior results) specific epithelial cell type.

FROM THE CLINICAL EDITOR

In this study of polystyrene nanoparticle trafficking across mouse alveolar epithelial cell monolayers, the authors determined that uptake/trafficking of nanoparticles into/across epithelial barriers is dependent on both nanoparticle physicochemical properties and the specific type of epithelial cells.

Challenges and opportunities in the advancement of nanomedicines

Nanomedicine-based approaches to cancer treatment face several challenges that differ from those encountered by conventional medicines during clinical development. A systematic exploration of these issues has led us to identify the following needs and opportunities for further development: (1) robust and general methods for the accurate characterization of nanoparticle size, shape, and composition; (2) scalable approaches for producing nanomedicines with optimized bioavailability and excretion profiles; (3) particle engineering for maintaining low levels of nonspecific cytotoxicity and sufficient stability during storage; (4) optimization of surface chemistries for maximum targeted delivery and minimum nonspecific adsorption; (5) practical methods for quantifying ligand density and distributions on multivalent nanocarriers; and (6) the design of multifunctional nanomedicines for novel combination therapies with supportable levels of bioaccumulation.

Gold nanoparticles: emerging paradigm for targeted drug delivery system

The application of nanotechnology in medicine, known as nanomedicine, has introduced a plethora of nanoparticles of variable chemistry and design considerations for cancer diagnosis and treatment. One of the most important field is the design and development of pharmaceutical drugs, based on targeted drug delivery system (TDDS). Being inspired by physio-chemical properties of nanoparticles, TDDS are designed to safely reach their targets and specifically release their cargo at the site of disease for enhanced therapeutic effects, thereby increasing the drug tissue bioavailability. Nanoparticles have the advantage of targeting cancer by simply being accumulated and entrapped in cancer cells. However, even after rapid growth of nanotechnology in nanomedicine, designing an effective targeted drug delivery system is still a challenging task. In this review, we reveal the recent advances in drug delivery approach with a particular focus on gold nanoparticles. We seek to expound on how these nanomaterials communicate in the complex environment to reach the target site, and how to design the effective TDDS for complex environments and simultaneously monitor the toxicity on the basis of designing such delivery complexes. Hence, this review will shed light on the research, opportunities and challenges for engineering nanomaterials with cancer biology and medicine to develop effective TDDS for treatment of cancer.

An enzyme-responsive nanocontainer as an intelligent signal-amplification platform for a multiple proteases assay

Based on selective pore-opening in the presence of protease, we have developed a novel signal amplification assay for multiple proteases detection and their inhibition using protein-capped mesoporous scaffolding as the substrate.