Tumor targeting and imaging in live animals with functionalized semiconductor quantum rods

Recent Nanocarrier Approaches for Targeted Drug Delivery in Cancer Therapy

Cancer is one of the most serious health concerns in the 21st century whose prevalence is beyond boundaries and can affect any organ of the human body. The conventional chemotherapeutic treatment strategies lack specificity to tumors and are associated with toxic effects on the immune system and other organ systems. In the past decades, there has been continuous progress in the development of smart nanocarrier systems for target-specific delivery of drugs against a variety of tumors, including intracellular gene-specific targeting. These nanocarriers are able to recognize the tumor cells and deliver the therapeutic agent in fixed proportions, causing no or very less harm to healthy cells. Nanosystems have modified physicochemical properties, improved bioavailability, and long retention in blood, which enhances their potency. A huge number of nanocarrier based formulations have been developed and are in clinical trials. Nanocarrier systems include polymeric micelles, liposomes, dendrimers, carbon nanotubes, gold nanoparticles, etc. Recent advancements in nanocarrier systems include mesoporous silica nanoparticles (MSNs), metal organic frameworks, and quantum dots. In the present review, various nanocarrier based drug delivery systems, along with their applications in the management of cancer, have been described with special emphasis on MSNs.

Anisotropic nanomaterials for shape-dependent physicochemical and biomedical applications

This review contributes towards a systematic understanding of the mechanism of shape-dependent effects on nanoparticles (NPs) for elaborating and predicting their properties and applications based on the past two decades of research. Recently, the significance of shape-dependent physical chemistry and biomedicine has drawn ever increasing attention. While there has been a great deal of effort to utilize NPs with different morphologies in these fields, so far research studies are largely localized in particular materials, synthetic methods, or biomedical applications, and have ignored the interactional and interdependent relationships of these areas. This review is a comprehensive description of the NP shapes from theory, synthesis, property to application. We figure out the roles that shape plays in the properties of different kinds of nanomaterials together with physicochemical and biomedical applications. Through systematic elaboration of these shape-dependent impacts, better utilization of nanomaterials with diverse morphologies would be realized and definite strategies would be expected for breakthroughs in these fields. In addition, we have proposed some critical challenges and open problems that need to be addressed in nanotechnology.

National Cancer Institute Alliance for nanotechnology in cancer-Catalyzing research and translation toward novel cancer diagnostics and therapeutics

Nanotechnology has been a burgeoning research field, which is finding compelling applications in several practical areas of everyday life. It has provided novel, paradigm shifting solutions to medical problems and particularly to cancer. In order to accelerate integration of nanotechnology into cancer research and oncology, the National Cancer Institute (NCI) of the National Institutes of Health (NIH) established the NCI Alliance for Nanotechnology in Cancer program in 2005. This effort brought together scientists representing physical sciences, chemistry, and engineering working at the nanoscale with biologists and clinicians working on cancer to form a uniquely multidisciplinary cancer nanotechnology research community. The last 14 years of the program have produced a remarkable body of scientific discovery and demonstrated its utility to the development of practical cancer interventions. This paper takes stock of how the Alliance program influenced melding of disparate research disciplines into the field of nanomedicine and cancer nanotechnology, has been highly productive in the scientific arena, and produced a mechanism of seamless transfer of novel technologies developed in academia to the clinical and commercial space. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

A general and rapid room-temperature synthesis approach for metal sulphide nanocrystals with tunable properties

Colloidal metal sulphide (MS) nanocrystals (NCs) have recently attracted considerable attention because of their tunable properties that can be exploited in various physical, chemical and biological applications. In this work, we present a novel and general method for synthesis of monodispersed binary (CuS, Ag2S, CdS, PbS, and SnS), ternary (Ag-In-S, Cu-In-S and Cu-Sn-S) and quaternary (Cu-Zn-Sn-S) MS NCs. The synthesis is conducted at room temperature, with an immediate crystallization process and up to 60 seconds of growth time, enabling rapid synthesis without external heating. For some of the ternary and quaternary NCs produced with relatively low crystallinity, we then carried out a "colloidal annealing" process to improve their crystallinity without changing their composition. Moreover, we show that the morphology and optical properties of the NCs can be tuned by varying the concentration of precursors and reaction time. The shape evolution and photoluminescence of particular MS NCs were also studied. These results not only provide insights into the growth mechanisms of MS NCs, but also yield a generalized, low cost, and potentially scalable method to fabricate them.

Peptide-based nanoprobes for molecular imaging and disease diagnostics

Pathological changes in a diseased site are often accompanied by abnormal activities of various biomolecules in and around the involved cells. Identifying the location and expression levels of these biomolecules could enable early-stage diagnosis of the related disease, the design of an appropriate treatment strategy, and the accurate assessment of the treatment outcomes. Over the past two decades, a great diversity of peptide-based nanoprobes (PBNs) have been developed, aiming to improve the in vitro and in vivo performances of water-soluble molecular probes through engineering of their primary chemical structures as well as the physicochemical properties of their resultant assemblies. In this review, we introduce strategies and approaches adopted for the identification of functional peptides in the context of molecular imaging and disease diagnostics, and then focus our discussion on the design and construction of PBNs capable of navigating through physiological barriers for targeted delivery and improved specificity and sensitivity in recognizing target biomolecules. We highlight the biological and structural roles that low-molecular-weight peptides play in PBN design and provide our perspectives on the future development of PBNs for clinical translation.

Clickable-Zwitterionic Copolymer Capped-Quantum Dots for in Vivo Fluorescence Tumor Imaging

In the last decades, fluorescent quantum dots (QDs) have appeared as high-performance biological fluorescent nanoprobes and have been explored for a variety of biomedical optical imaging applications. However, many central challenges still exist concerning the control of the surface chemistry to ensure high biocompatibility, low toxicity, antifouling, and specific active targeting properties. Regarding in vivo applications, circulation time and clearance of the nanoprobe are also key parameters to control the design and characterization of new optical imaging agents. Herein, the complete design and characterization of a peptide-near-infrared-QD-based nanoprobe for biomedical optical imaging is presented from the synthesis of the QDs and the zwitterionic-azide copolymer ligand, enabling a bio-orthogonal coupling, till the final in vivo test through all the characterization steps. The developed nanoprobes show high fluorescence emission, controlled grafting rate, low toxicity, in vitro active specific targeting, and in vivo long circulating blood time. This is, to our knowledge, the first report characterizing the in vivo circulation kinetics and tumor accumulation of targeted zwitterionic QDs.

Nanoimaging: photophysical and pharmaceutical characterization of poly-lactide-co-glycolide nanoparticles engineered with quantum dots

Quantum dots (QDs) and polymeric nanoparticles (NPs) are considered good binomials for the development of multifunctional nanomedicines for multimodal imaging. Fluorescent imaging of QDs can monitor the behavior of QD-labeled NPs in both cells and animals with high temporal and spatial resolutions. The comprehension of polymer interaction with the metallic QD surface must be considered to achieve a complete chemicophysical characterization of these systems and to describe the QD optical properties to be used for their unequivocal identification in the tissue. In this study, by comparing two different synthetic procedures to obtain polymeric nanoparticles labeled with QDs, we investigated whether their optical properties may change according to the formulation methods, as a consequence of the different polymeric environments. Atomic force microscopy, transmission electron microscopy, confocal and fluorescence lifetime imaging microscopy characterization demonstrated that NPs modified with QDs after the formulation process (post-NPs-QDs) conserved the photophysical features of the QD probe. In contrast, by using a polymer modified with QDs to formulate NPs (pre-NPs-QDs), a significant quenching of QD fluorescence and a blueshift in its emission spectra were observed. Our results suggest that the packaging of QDs into the polymeric matrix causes a modification of the QD optical properties: these effects must be characterized in depth and carefully considered when developing nanosystems for imaging and biological applications.

Metal chalcogenide quantum dots: biotechnological synthesis and applications

Metal chalcogenide (metal sulfide, selenide and telluride) quantum dots (QDs) have attracted considerable attention due to their quantum confinement and size-dependent photoemission characteristics.

Targeted highly sensitive detection/eradication of multi-drug resistant Salmonella DT104 through gold nanoparticle-SWCNT bioconjugated nanohybrids

Monoclonal antibody-conjugated sphere-shaped gold nanoparticles were combined with single-walled carbon nanotubes (SWCNTs) to create a nanohybrid system to selectively detect and eradicate multiple drug resistant Salmonella (MDRS) typhimurium DT104 bacteria. The Raman signal intensity from Rhodamine 6G (Rh6G) modified monoclonal AC04 antibody SWCNTs-gold nanoparticle (SWCNT-GNPs) hybrid provided a SERS enhancement by several orders of magnitude to detect the MDRS bacteria over the GNP system. A targeted photothermolysis experiment using 670 nm light at 2 W cm(-2) for 15 min, resulted in selective and irreparable damage to more than 99% Salmonella DT104 at the concentration of 10(5) CFU mL(-1). In comparison to solely SWCNTs or GNPs, our SWCNT-GNPs nanohybrids have also shown a better photothermal efficiency.

Quantum dots: bright and versatile in vitro and in vivo fluorescence imaging biosensors

Colourful cells and tissues: semiconductor quantum dots and their versatile applications in multiplexed bioimaging research.

Biocompatible near-infrared fluorescent nanoparticles for macro and microscopic in vivo functional bioimaging

Near-infrared (NIR) imaging technology has been widely used for biomedical research and applications, since it can achieve deep penetration in biological tissues due to less absorption and scattering of NIR light. In our research, polymer nanoparticles with NIR fluorophores doped were synthesized. The morphology, absorption/emission features and chemical stability of the fluorescent nanoparticles were characterized, separately. NIR fluorescent nanoparticles were then utilized as bright optical probes for macro in vivo imaging of mice, including sentinel lymph node (SLN) mapping, as well as distribution and excretion monitoring of nanoparticles in animal body. Furthermore, we applied the NIR fluorescent nanoparticles in in vivo microscopic bioimaging via a confocal microscope. Under the 635 nm-CW excitation, the blood vessel architecture in the ear and the brain of mice, which were administered with nanoparticles, was visualized very clearly. The imaging depth of our one-photon microscopy, which was assisted with NIR fluorescent nanoprobes, can reach as deep as 500 μm. Our experiments show that NIR fluorescent nanoparticles have great potentials in various deep-tissue imaging applications.

Peptidic ligands to control the three-dimensional self-assembly of quantum rods in aqueous media

The use of peptidic ligands is validated as a generic chemical platform allowing one to finely control the organization in solid phase of semiconductor nanorods originally dispersed in an aqueous media. An original method to generate, on a macroscopic scale and with the desired geometry, three-dimensional supracrystals composed of quantum rods is introduced. In a first step, nanorods are transferred in an aqueous phase thanks to the substitution of the original capping layer by peptidic ligands. Infrared and nuclear magnetic resonance spectroscopy data prove that the exchange is complete; fluorescence spectroscopy demonstrates that the emitter optical properties are not significantly altered; electrophoresis and dynamic light scattering experiments assess the good colloidal stability of the resulting aqueous suspension. In a second step, water evaporation in a microstructured environment yields superstructures with a chosen geometry and in which nanorods obey a smectic B arrangement, as shown by electron microscopy. Incidentally, bulk drying in a capillary tube generates a similar local order, as evidenced by small angle X-ray scattering.

Advances in imaging probes and optical microendoscopic imaging techniques for early in vivo cancer assessment

A new chapter in the history of medical diagnosis happened when the first X-ray technology was invented in the late 1800s. Since then, many non-invasive and minimally invasive imaging techniques have been invented for clinical diagnosis to research in cellular biology, drug discovery, and disease monitoring. These imaging modalities have leveraged the benefits of significant advances in computer, electronics, and information technology and, more recently, targeted molecular imaging. The development of targeted contrast agents such as fluorescent and nanoparticle probes coupled with optical imaging techniques has made it possible to selectively view specific biological events and processes in both in vivo and ex vivo systems with great sensitivity and selectivity. Thus, the combination of targeted molecular imaging probes and optical imaging techniques have become a mainstay in modern medicinal and biological research. Many promising results have demonstrated great potentials to translate to clinical applications. In this review, we describe a discussion of employing imaging probes and optical microendoscopic imaging techniques for cancer diagnosis.

Quantum dot-based nanoprobes for in vivo targeted imaging

Fluorescent semiconductor quantum dots (QDs) have attracted tremendous attention over the last decade. The superior optical properties of QDs over conventional organic dyes make them attractive labels for a wide variety of biomedical applications, whereas their potential toxicity and instability in biological environment have puzzled scientific researchers. Much research effort has been devoted to surface modification and functionalization of QDs to make them versatile probes for biomedical applications, and significant progress has been made over the last several years. This review article aims to describe the current state-of-the-art of the synthesis, modification, bioconjugation, and applications of QDs for in vivo targeted imaging. In addition, QD-based multifunctional nanoprobes are also summarized.

Photosensitive fluorescent dye contributes to phototoxicity and inflammatory responses of dye-doped silica NPs in cells and mice

Dye-doped fluorescent silica nanoparticles provide highly intense and photostable fluorescence signals. However, some dopant dye molecules are photosensitive. A widely-used photosensitive fluorescent dopant, RuBpy, was chosen to systematically investigate the phototoxicity of the dye-doped silica nanoparticles (NPs). We investigated cell viability, DNA damage, and Reactive Oxygen Species (ROS) levels in alveolar macrophages using the dye-doped NPs with or without irradiation. Our results showed that the RuBpy-doped silica NPs could induce significant amount of ROS, DNA damage, apoptosis and impaired proliferation in MH-S cells. In vivo studies in mice showed that RuBpy-doped silica NPs induced significant inflammatory cytokine production and lowered expression in signaling proteins such as ERK1/2 and NF-κB as well as increased lung injury determined by myeloperoxidase and lipid peroxidation. Strikingly, we also found that both RuBpy alone and NPs induced systemic signaling activation in the kidney compared to the liver and lung where showed highly selective signaling patterns, which is more pronounced than RuBpy-doped silica NPs. Moreover, we discovered a critical biomarker (e.g., HMGB1) for silica NPs-induced stress and toxicity and demonstrated differentially-regulated response patterns in various organs. Our results indicate for the first time that the RuBpy-doped silica NPs may impose less inflammatory responses but stronger thermotherapeutic effects on target cells in animals than naked NPs in a time- and dose-dependent manner.

Functionalization of small rigid platforms with cyclic RGD peptides for targeting tumors overexpressing αvβ3-integrins

Gadolinium based Small Rigid Plaforms (SRPs) have previously demonstrated their efficiency for multimodal imaging and radiosensitization. Since the RGD sequence is well-known to be highly selective for αvβ3 integrins, a cyclic pentapeptide containing the RGD motif (cRGDfK) has been grafted onto the SRP surface. An appropriate protocol led to the grafting of two targeting ligands per nano-object. The resulting nanoparticles have demonstrated a strong association with αvβ3 integrins in comparison with cRADfK grafted SRPs as negative control. Flow cytometry and fluorescence microscopy have also been used to highlight the ability of the nanoparticles to target efficiently HEK293(β3) and U87MG cells. Finally the grafted radiosensitizing nanoparticles were intravenously injected into Nude mice bearing subcutaneous U87MG tumors and the signal observed by optical imaging was twice as high for SRP-cRGDfK compared to their negative analogue.

Nanotoxicity assessment of quantum dots: from cellular to primate studies

Tremendous research efforts have been devoted to fabricating high quality quantum dots (QDs) for applications in biology and medicine. Much of this research was pursued with an ultimate goal of using QDs in clinical applications. However, a great deal of concern has been voiced about the potential hazards of QDs due to their heavy-metal content. Many studies have demonstrated toxicity of various QDs in cell culture studies. However, in a smaller number of studies using small animal models (mice and rats), no abnormal behaviour or tissue damage was noticed over periods of months after the systemic administration of QDs. Nevertheless, the correlation of these results with the potential for negative effects of QD on humans remains unclear. Many urgent questions must be answered before the QDs community moves into the clinical research phase. This review provides an overview of the toxicity assessment of QDs, ranging from cell culture studies to animal models and discusses their findings. Guidelines for using various nonhuman primate models for QD toxicity studies are highlighted. This review article is intended to promote the awareness of current developments of QD applications in biology, the potential toxicity of QDs, and approaches to minimizing toxicity.

Quantum dots for cancer research: current status, remaining issues, and future perspectives

Cancer is a major threat to public health in the 21st century because it is one of the leading causes of death worldwide. The mechanisms of carcinogenesis, cancer invasion, and metastasis remain unclear. Thus, the development of a novel approach for cancer detection is urgent, and real-time monitoring is crucial in revealing its underlying biological mechanisms. With the optical and chemical advantages of quantum dots (QDs), QD-based nanotechnology is helpful in constructing a biomedical imaging platform for cancer behavior study. This review mainly focuses on the application of QD-based nanotechnology in cancer cell imaging and tumor microenvironment studies both in vivo and in vitro, as well as the remaining issues and future perspectives.

Surface engineering of inorganic nanoparticles for imaging and therapy

Many kinds of inorganic nanoparticles (NPs) including semiconductor, metal, metal oxide, and lanthanide-doped NPs have been developed for imaging and therapy applications. Their unique optical, magnetic, and electronic properties can be tailored by controlling the composition, size, shape, and structure. Interaction of such NPs with cells and/or in vivo compartments is critically determined by the surface properties, and sophisticated control over the NP surface is essential to control their fate in biological environments. We review NP surface coating strategies using the categories of small surface ligand, polymer, and lipid. Use of small ligand molecules has the advantage of maintaining the minimal hydrodynamic (HD) size. Polymers can be advantageous in NP anchoring by combining multiple affinity groups. Encapsulation of NPs in polymers, lipids or surfactants can preserve the as-synthesized NPs. NP surface properties and reaction conditions should be carefully considered to obtain a bioconjugate that maintains the physicochemical properties of NP and functionalities of the conjugated biomolecules. We highlight how the surface properties of NPs impact their interactions with cells and in vivo compartments, especially focused on the important surface design parameters such as HD size, surface charge, and targeting. Typically, maximal cellular uptake can take place in the intermediate NP size range of 40-60nm. Clearance of NPs from blood circulation is largely dependent on the degree of uptake by reticuloendothelial system when they are larger than 10nm. When the HD size is below 10nm, NPs show broad distribution over many organs. Reduction of HD size below the limit of renal barrier can achieve fast clearance of NPs. For maximal tumor accumulation, NPs should have long blood circulation time and should be large enough to prevent rapid penetration. NPs are also desired to rapidly clear out from the body after the mission before they cause toxic side effects. However, efficient clearance from the body to avoid side effects may result in the reduction in residence time required for accumulation in target tissues. Smart design of NP surface coating that can meet the conflicting demands can open a new avenue of NP applications. Surface charge and hydrophobicity need to be carefully considered for NP surface design. Positively charged NPs more adsorb on cell membranes and consequently show higher level of internalizations when compared with negatively charged or neutral NPs. NPs encounter a large variety of biomolecules in vivo, where non-specific adsorptions can potentially alter the physicochemical properties of the NPs. For optimal performance, NPs are suggested to have neutral surface charge at physiological conditions, small HD size, and minimal non-specific adsorption levels. Zwitterionic NP surface coating by small surface ligands can be a promising approach. Toxicity is one of most critical issues, where proper control of the NP surface can significantly reduce the toxicities.

Exogenous near-infrared fluorophores and their applications in cancer diagnosis: biological and clinical perspectives

INTRODUCTION

Near-infrared fluorescent (NIRF) imaging is a rapidly growing research field which has the potential to be an important imaging modality in cancer diagnosis. Various exogenous NIR fluorophores have been developed for the technique, including small molecule fluorophores and nanoparticles. NIRF imaging has been used in animal models for the detection of cancer overthe last twenty years and has in recent years been used in human clinical trials.

AREAS COVERED

This article describes the types and characteristics of exogenous fluorophores available for in vivo fluorescent cancer imaging. The article also discusses the progression of NIRF cancer imaging over recent years and its future challenges, from both a biological and clinical perspective. in The review also looks at its application for lymph node mapping, tumor targeting and characterization, and tumor margin definition for surgical guidance.

EXPERT OPINION

NIRF imaging is not in routine clinical cancer practice; yet, the authors predict that techniques using NIR fluorophores for tumor margin definition and lymph node mapping will enter clinical practice in the near future. The authors also anticipate that NIRF imaging research will lead to the development of flurophores with 'high brightness' that will overcome the limited penetration of this modality and be better suited for non invasive tumor targeting.

Synthesis of luminescent near-infrared AgInS2 nanocrystals as optical probes for in vivo applications

Near infrared quantum dots have been receiving great attention as fluorescent optical probes for in vivo imaging applications. In this contribution, we report the synthesis and surface functionalization of cadmium free ternary AgInS2 nanocrystals emitting in the near infrared range for successful in vitro and in vivo bioimaging applications. The FDA approved triblock copolymer Pluronic F127 was used to encapsulate the nanocrystals and made them dispersible in aqueous solution. By employing a whole body small animal optical imaging setup, we were able to use the AgInS2 nanocrystals formulation for passive targeted delivery to the tumor site. The ultra-small crystal size, near-infrared emitting luminescence, and high quantum yield make the AgInS2 nanocrystals an attractive candidate as a biological contrast agent for cancer sensing and imaging.

Image guided biodistribution and pharmacokinetic studies of theranostics

Image guided technique is playing an increasingly important role in the investigation of the biodistribution and pharmacokinetics of drugs or drug delivery systems in various diseases, especially cancers. Besides anatomical imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), molecular imaging strategy including optical imaging, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) will facilitate the localization and quantization of radioisotope or optical probe labeled nanoparticle delivery systems in the category of theranostics. The quantitative measurement of the bio-distribution and pharmacokinetics of theranostics in the fields of new drug/probe development, diagnosis and treatment process monitoring as well as tracking the brain-blood-barrier (BBB) breaking through by high sensitive imaging method, and the applications of the representative imaging modalities are summarized in this review.

Fluorescence resonance energy transfer mediated large Stokes shifting near-infrared fluorescent silica nanoparticles for in vivo small-animal imaging

Fluorescent dye-doped silica nanoparticles are increasingly used for in vivo imaging due to their unique biocompatibility and easy surface modification. However, the utility of existing fluorescent dye-doped silica nanoparticles for in vivo imaging is still limited because most studies are focused on doping single near-infrared (NIR) dyes in the silica matrix, which would cause background and crosstalk between the excitation light and the emitting signals due to the small Stokes shift of the traditional NIR dyes. To address this issue, we present a novel large Stokes shifting NIR fluorescent silica nanoparticles (LSS-NFSiNPs) based on the principle of fluorescence resonance energy transfer. Two highly water-soluble dyes, tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate (RuBpy) and methylene blue (MB), were chose as the model donor-acceptor pair. The LSS-NFSiNPs were prepared by synchronously doping RuBpy and MB in the silica nanoparticles. By optimizing the molar ratio of RuBpy and MB for doping in the silica nanoparticles, the energy transfer from RuBpy to MB occurred in the silica matrix, resulting in a near-infrared fluorescent silica nanoparticles with strong fluorescence and large Stokes shift (>200 nm). As a result, it can effectively help to increase the discrimination of fluorescence signal of interest over other background signals. With a combination of excellent stability, large Stokes shift, and near-infrared spectral properties, this novel LSS-NFSiNPs provides real-time, deep-tissue fluorescent imaging of live animals. More importantly, the LSS-NFSiNPs can also be gradually cleared from the body through the urinary clearance system. We anticipate this design concept can lay a foundation for further development of in vivo optical nanoparticulate contrast toward clinical applications.

Emerging inorganic nanomaterials for pancreatic cancer diagnosis and treatment

Pancreatic cancer is a devastating disease with incidence increasing at an alarming rate and survival not improved substantially during the past three decades. Although enormous efforts have been made in early detection and comprehensive treatment for this disease, little or no survival improvement was obtained, which necessitates the development of novel strategies. Emerging inorganic nanomaterials, such as carbon nanotubes, quantum dots, mesoporous silica/gold/supermagnetic nanoparticles, have been widely used in biomedical research with great optimism for cancer diagnosis and therapy. Such nanoparticles possess unique optical, electrical, magnetic and/or electrochemical properties. With such properties along with their impressive nano-size, these particles can be targeted to cancer cells, tissues, and ligands efficiently and monitored with extreme precision in real-time. In additional to liposome, dendrimer, and polymeric nanoparticles, they are considered the most promising nanomaterials with the capability of both cancer detection and multimodality treatment. Emerging approaches to harness nanotechnology to optimize the existing diagnostic and therapeutic tools for pancreatic cancer have been extensively explored during the recent years. Future options for early detection, individual therapy and monitoring responses of pancreatic cancer are focused on multifunctional nanomedicine. In this review, we present the recent development of clinically applicable inorganic nanoparticles, with focus on the diagnosis and treatment of pancreatic cancer. Furthermore, their advantages in theranostic nanomedicine, and challenges of translation to clinical practice, are discussed.

Bioconjugated pluronic triblock-copolymer micelle-encapsulated quantum dots for targeted imaging of cancer: in vitro and in vivo studies

Early in this study, CdTe/ZnS core/shell quantum dots (QDs) were encapsulated in carboxylated Pluronic F127 triblock polymeric micelle, to preserve the optical and colloidal stability of QDs in biological fluids. Folic acid (FA) was then conjugated to the surface of QDs for the targeted delivery of the QD formulation to the tumor site, by exploiting the overexpressed FA receptors (FARs) on the tumor cells. Cytotoxicity study demonstrated that the QD formulation has negligible in vitro toxicity. The in vitro study showed that the bioconjugated micelle-encapsulated QDs, but not the unconjugated QDs, were able to efficiently label Panc-1 cancer cells. In vivo imaging study showed that bioconjugated QDs were able to target tumor site after intravenous injection of the formulation in tumor-bearing mice.

Preparation of quantum dot/drug nanoparticle formulations for traceable targeted delivery and therapy

Quantum dots (QDs) are luminescent nanocrystals with rich surface chemistry and unique optical properties that make them useful as probes or carriers for traceable targeted delivery and therapy applications. QDs can be functionalized to target specific cells or tissues by conjugating them with targeting ligands. Recent advancement in making biocompatible QD formulations has made these nanocrystals suitable for in vivo applications. This review provides an overview of the preparation of QDs and their use as probes or carriers for traceable, targeted therapy of diseases in vitro and in vivo. More specifically, recent advances in the integration of QDs with drug formulations for therapy and their potential toxicity in vitro and in vivo are highlighted. The current findings and challenges for optimizing QD/drug formulations with respect to optimal size and stability, short-term and long-term toxicity, and in vivo applications are described. Lastly, we attempt to predict key trends in QD/drug formulation development over the next few years and highlight areas of therapy where their use may provide breakthrough results in the near future.

Gene Silencing of Human Neuronal Cells for Drug Addiction Therapy using Anisotropic Nanocrystals

Theranostic platform integrating diagnostic imaging and therapeutic function into a single system has become a new direction of nanoparticle research. In the process of treatment, therapeutic efficacy is monitored. The use of theranostic nanoparticle can add an additional "layer" to keep track on the therapeutic agent such as the pharmacokinetics and biodistribution. In this report, we have developed quantum rod (QR) based formulations for the delivery of small interfering RNAs (siRNAs) to human neuronal cells. PEGlyated QRs with different surface functional groups (amine and maleimide) were designed for selectively down-regulating the dopaminergic signaling pathway which is associated with the drug abuse behavior. We have demonstrated that the DARPP-32 siRNAs were successfully delivered to dopaminergic neuronal (DAN) cells which led to drastic knockdown of specific gene expression by both the electrostatic and covalent bond conjugation regimes. The PEGlyated surface offered high biocompatibilities and negligible cytotoxicities to the QR formulations that may facilitate the in vivo applications of these nanoparticles.

Noninvasive real-time fluorescence imaging of the lymphatic uptake of BSA-IRDye 680 conjugate administered subcutaneously in mice

The goal of our studies was to determine lymphatic uptake of bovine serum albumin (BSA) using real-time noninvasive fluorescence imaging. BSA labeled with near-infrared dye (IRDye) 680 was used as a model protein-dye conjugate. The conjugation of BSA with IRDye 680 was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Size-exclusion high-performance liquid chromatography and SDS-PAGE demonstrated that the IRDye 680-labeled BSA conjugate in the lymph node (LN) homogenate samples was stable at physiological temperature (37°C) for at least 5 days. Whole-body noninvasive optical imaging of hairless SKH-1 mice was performed after subcutaneous (s.c.) injection (dose = 0.1 mg/kg) into the front footpad. Noninvasive fluorescence imaging demonstrated that BSA-IRDye 680 conjugates were dynamically taken up by the lymphatic system, accumulated in the axillary LNs and then cleared, indicating that lymphatic transport plays a role in the absorption of BSA. Ex vivo tissue imaging of LN homogenates provided confirmatory data with respect to the uptake of fluorescent-labeled BSA determined by in vivo imaging. Noninvasive real-time imaging of LNs provides a novel tool for evaluating uptake and accumulation of fluorescent-labeled proteins by the lymphatic system after s.c. injection in a mouse model.

Gold nano-popcorn attached SWCNT hybrid nanomaterial for targeted diagnosis and photothermal therapy of human breast cancer cells

Breast cancer presents greatest challenge in health care in today's world. The key to ultimately successful treatment of breast cancer disease is an early and accurate diagnosis. Current breast cancer treatments are often associated with severe side effects. Driven by the need, we report the design of novel hybrid nanomaterial using gold nano popcorn-attached single wall carbon nanotube for targeted diagnosis and selective photothermal treatment. Targeted SK-BR-3 human breast cancer cell sensing have been performed in 10 cancer cells/mL level, using surface enhanced Raman scattering of single walls carbon nanotube's D and G bands. Our data show that S6 aptamer attached hybrid nanomaterial based SERS assay is highly sensitive to targeted human breast cancer SK-BR-3 cell line and it will be able to distinguish it from other non targeted MDA-MB breast cancer cell line and HaCaT normal skin cell line. Our results also show that 10 min of photothermal therapy treatment by 1.5 W/cm(2) power, 785 nm laser is enough to kill cancer cells very effectively using S6 aptamer attached hybrid nanomaterials. Possible mechanisms for targeted sensing and operating principle for highly efficient photothermal therapy have been discussed. Our experimental results reported here open up a new possibility for using aptamers modified hybrid nanomaterial for reliable diagnosis and targeted therapy of cancer cell lines quickly.

Highly emissive nano rod-in-rod heterostructures with strong linear polarization

We report the synthesis of CdSe/CdS rod in rod core/shell heterostructures. These rods, synthesized using a seeded-growth approach, show narrow distributions of rod diameters and lengths and exhibit high emission quantum efficiencies and highly polarized emission. The degree of polarization is controlled by the inner core rod dimensions, and it is equal or up to 1.5 times higher than the polarization of equivalent sphere in rod systems. Using the method of photoselection we measure the polarization anisotropy at different excitation wavelengths and study the interplay between electronic contribution and dielectric effects in determining the absorption and emission polarization.

Bioconjugated PLGA-4-arm-PEG branched polymeric nanoparticles as novel tumor targeting carriers

In this study, we have developed a novel carrier, micelle-type bioconjugated PLGA-4-arm-PEG branched polymeric nanoparticles (NPs), for the detection and treatment of pancreatic cancer. These NPs contained 4-arm-PEG as corona, and PLGA as core, the particle surface was conjugated with cyclo(arginine-glycine-aspartate) (cRGD) as ligand for in vivo tumor targeting. The hydrodynamic size of the NPs was determined to be 150-180 nm and the critical micellar concentration (CMC) was estimated to be 10.5 mg l( - 1). Our in vitro study shows that these NPs by themselves had negligible cytotoxicity to human pancreatic cancer (Panc-1) and human glioblastoma (U87) cell lines. Near infrared (NIR) microscopy and flow cytometry demonstrated that the cRGD conjugated PLGA-4-arm-PEG polymeric NPs were taken up more efficiently by U87MG glioma cells, over-expressing the α(v)β(3) integrin, when compared with the non-targeted NPs. Whole body imaging showed that the cRGD conjugated PLGA-4-arm-PEG branched polymeric NPs had the highest accumulation in the pancreatic tumor site of mice at 48 h post-injection. Physical, hematological, and pathological assays indicated low in vivo toxicity of this NP formulation. These studies on the ability of these bioconjugated PLGA-4-arm-PEG polymeric NPs suggest that the prepared polymeric NPs may serve as a promising platform for detection and targeted drug delivery for pancreatic cancer.

Fluorescent nanoparticle probes for imaging of cancer

Fluorescent nanoparticles (FNPs) have received immense popularity in cancer imaging in recent years because of their attractive optical properties. In comparison to traditional organic-based fluorescent dyes and fluorescent proteins, FNPs offer much improved sensitivity and photostability. FNPs in certain size range have a strong tendency to enter and retain in solid tumor tissue with abnormal (leaky) vasculature--a phenomenon known as Enhanced Permeation and Retention (EPR) effect, advancing their use for in vivo tumor imaging. Furthermore, large surface area of FNPs and their usual core-shell structure offer a platform for designing and fabricating multimodal/multifunctional nanoparticles (MMNPs). For effective cancer imaging, often the optical imaging modality is integrated with other nonoptical-based imaging modalities such as MRI, X-ray, and PET, thus creating multimodal nanoparticle (NP)-based imaging probes. Such multimodal NP probes can be further integrated with therapeutic drug as well as cancer targeting agent leading to multifunctional NPs. Biocompatibility of FNPs is an important criterion that must be seriously considered during FNP design. NP composition, size, and surface chemistry must be carefully selected to minimize potential toxicological consequences both in vitro and in vivo. In this article, we will mainly focus on three different types of FNPs: dye-loaded NPs, quantum dots (Qdots), and phosphores; briefly highlighting their potential use in translational research.

Non-invasive tumor detection in small animals using novel functional Pluronic nanomicelles conjugated with anti-mesothelin antibody

In this study QDs were encapsulated in carboxylated PluronicF127 (F127COOH) triblock polymeric micelles and conjugated with anti-mesothelin antibody for the purpose of alleviating potential toxicity, enhancing the stability and improving targeting efficiency of CdTe/ZnS quantum dots (QDs) in tumors. The amphiphilic triblock polymer of F127COOH contains hydrophilic carboxylated poly(ethylene oxide) (PEO) and hydrophobic poly(propylene oxide) (PPO) units. After encapsulating QDs into carboxylated F127 (F127COOH-QD) micelles, the particles were conjugated with anti-mesothelin antibodies to allow targeting of cancerous areas. The size of the monodispersed spherical QD-containing micelles was determined to be ∼120 nm by dynamic light scattering (DLS). The critical micelle concentration (CMC) was estimated to be 4.7 × 10(-7) M. In an in vitro study, the anti-methoselin antibody conjugated F127COOH (Me-F127COOH-QD) nanomicelles showed negligible cytotoxicity to pancreatic cancer cells (Panc-1). Confocal microscopy demonstrated that the Me-F127COOH-QD nanomicelles were taken up more efficiently by Panc-1 cells, due to antibody mediated targeting. An in vivo imaging study showed that Me-F127COOH-QD nanomicelles accumulated at the pancreatic tumor site 15 min after intravenous injection. In addition, the low in vivo toxicity of the nanomicellar formulation was evaluated by pathological assays. These results suggest that anti-mesothein antibody conjugated carboxylated F127 nanomicelles may serve as a promising nanoscale platform for early human pancreatic cancer detection and targeted drug delivery.

Nanomaterials: applications in cancer imaging and therapy

The application of nanomaterials (NMs) in biomedicine is increasing rapidly and offers excellent prospects for the development of new non-invasive strategies for the diagnosis and treatment of cancer. In this review, we provide a brief description of cancer pathology and the characteristics that are important for tumor-targeted NM design, followed by an overview of the different types of NMs explored to date, covering synthetic aspects and approaches explored for their application in unimodal and multimodal imaging, diagnosis and therapy. Significant synthetic advances now allow for the preparation of NMs with highly controlled geometry, surface charge, physicochemical properties, and the decoration of their surfaces with polymers and bioactive molecules in order to improve biocompatibility and to achieve active targeting. This is stimulating the development of a diverse range of nanometer-sized objects that can recognize cancer tissue, enabling visualization of tumors, delivery of anti-cancer drugs and/or the destruction of tumors by different therapeutic techniques.

Efficient preparation and labeling of human induced pluripotent stem cells by nanotechnology

Efficient preparation and labeling of human induced pluripotent stem (iPS) cells is a great challenge in stem cell research and development. With the aim of investigating the feasibility of using nanotechnology to enhance the preparation efficiency of iPS cells and to label iPS cells for long-term tracing and imaging, in this paper, four transcription factor genes, ie, Oct4, Sox2, LIN28, and Nanog, and packaging plasmids such as PSPAX2 and PMD2.G were cotransfected into 293T cells using Generation 5.0 polyamidoamine dendrimer-modified magnetic nanoparticles (dMNPs) as a delivery system. The resultant supernatant liquids were incubated with human fibroblast cells at 37°C for 21 days, then the embryonic stem (ES) cell-like clones were screened, cultured, and identified. Finally, the prepared iPS cells were labeled with fluorescent magnetic nanoparticles (FMNPs). The results showed that dMNPs can efficiently deliver all vectors into 293T cells. The resultant lentiviruses’ titers were 10-fold more than those based on Lipofectamine™ 2000. Reverse transcription polymerase chain reaction analysis showed that four genes (Oct4, Sox2, LIN28, and Nanog) exhibited different expressions in iPS cells. Immunostaining analysis showed that specific surface markers of ES cells such as SSEA-3, SSEA-4, Tra-1-60, and Tra-1-81 were positive in iPS cells, and the terotomas were formed in NOD-SCID mice that were implanted with iPS cells. Red fluorescent signals could be observed in iPS cells labeled with FMNPs by fluorescent microscopy, and the magnetic signals were detected in labeled iPS cells by magnetic resonance imaging. In conclusion, human iPS cells can be efficiently generated using polyamidoamine dMNPs and lentivirus and labeled with FMNPs for long-term observation and tracking, which has great potential application in the research and development of stem cells in the near future.

Anti-claudin-4-conjugated highly luminescent nanoparticles as biological labels for pancreatic cancer sensing

Anti-claudin-4, whose corresponding antigen receptors are known to be overexpressed in both primary and metastatic human pancreatic cancer, is utilized for targeted delivery and imaging of pancreatic cancer. In this protocol, we describe the use of quantum dots (QDs) as sensitive optical contrast agent for imaging pancreatic cancer in vitro and in vivo by using anti-claudin-4 as targeting ligands. The claudin-4-mediated targeting is demonstrated in using both in vitro confocal microscopy and in vivo tumor imaging system. This targeted QD platform will be further modified for the purpose of developing as an early detection imaging tool for pancreatic cancer.

Synthesis of CdTe/CdS/ZnS quantum dots and their application in imaging of hepatocellular carcinoma cells and immunoassay for alpha fetoprotein

We report the imaging of hepatocellular carcinoma cells and the immunoassay for alpha fetoprotein (AFP) using CdTe/CdS/ZnS core-shell-shell QDs. Stable and high PLQY (20%-48%) CdTe/CdS/ZnS core-shell-shell QDs were synthesized by a stepwise process. Bioconjugation of the core-shell-shell QDs with streptavidin (SA) was successfully applied in immunofluorescent imaging of the human hepatocellular carcinoma (HCC) cell line HepG2.2.15. Furthermore, the thioglycolic acid (TGA)-capped CdTe/CdS/ZnS core-shell-shell QDs fluorescence lifetime is longer than fluorescein, so it was first engaged to conjugate with antigen for the determination of protein (AFP) by fluorescence polarization immunoassay.

Quantum dots synthesis and biological applications as imaging and drug delivery systems

Semiconductor quantum dots (QDs) synthesized by metal ions and colloid stabilizers have been explored as promising probes in advanced imaging techniques, tumor diagnostic agents, and drug delivery systems. The ability to modulate QDs surface chemistry through particle--shape control, surface coating, and surface functionalization-has rendered them a valuable tool in biological sciences. The tremendous advances in nanotechnology revealed the unique properties of QD crystals in both in vitro and in vivo conditions. In this review, we summarize the recent trends in QD synthesis, surface modification, and biological applications particularly for cancer targeting and treatment.