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

Technetium-99m radiolabeling of graphene quantum dots (GQDs) as a new probe for glioblastoma tumor imaging

PURPOSE

Cancer diagnosis involves a multi-step process. Accurate identification of the tumor, staging and development of cancer cells is crucial for selecting optimal treatments to minimize disease recurrence. Quantum dots (QDs) represent an exciting class of fluorescent nanoprobes in molecular detection and targeted tumor imaging.

MATERIALS AND METHODS

In this study, graphene quantum dots (GQDs) were synthesized by pyrolysis of citric acid (CA) as a carbon precursor under high temperatures. The morphology of the obtained GQDs was first characterized using physical (TEM and DLS) and spectroscopic (fluorescence, FTIR and UV-Vis) methods. In the following,99mTc-labeled GQDs were prepared in the presence of SnCl2.2H2O as a reducing agent between 95 and 100 °C. The biodistribution and tumor targeting efficiency of radiolabeled GQDs as a novel agent for C6 glioma tumor scintigraphy in an animal model were evaluated. Furthermore, organ uptake, human serum albumin binding and tumor accumulation were measured.

RESULTS

The TEM image of the prepared GQDs showed a relatively uniform size distribution in the range of diameter 6-9 nm and spherical shape. Radiolabeled GQDs showed a radiochemical yield of >97% (n = 3). Through incubation in human serum, almost 15% of 99mTc-labeled GQDs degraded after 6 h. The amount of uptake in xenograft models of glioma C6 rats was 1.10 ± 0.36% of injection dose per gram after 1 h. The kidneys, intestinal and glioma tumor sites were observed via scintigraphy imaging.

CONCLUSION

Our data suggest that 99mTc-labeled GQDs, as a new radiotracer, efficiently accumulate in the tumor site and could be included as a radiotracer for detecting glioma tumors.

Anticancer activity of quantum size carbon dots: opportunities and challenges

Research into the anticancer activity of quantum-sized carbon dots (CDs) has emerged as a promising avenue in cancer research. This CDs delves into the opportunities and challenges associated with harnessing the potential of these nanostructures for combating cancer. Quantum-sized carbon dots, owing to their unique physicochemical properties, exhibit distinct advantages as potential therapeutic agents. Opportunities lie in their tunable size, surface functionalization capabilities, and biocompatibility, enabling targeted drug delivery and imaging in cancer cells. However, we include challenges, a comprehensive understanding of the underlying mechanisms, potential toxicity concerns, and the optimization of synthesis methods for enhanced therapeutic efficacy. A succinct summary of the state of the research in this area is given in this review, emphasizing the exciting possibilities and ongoing challenges in utilizing quantum-sized carbon dots as a novel strategy for cancer treatment.

Core-Tunable Dendritic Polymer: A Folate-Guided Theranostic Nanoplatform for Drug Delivery Applications

Clinical application of anticancer drugs is mostly limited due to their hydrophobic nature, which often results in lower bioavailability and lesser retention in systemic circulation. Despite extensive research on the development of targeted drug delivery systems for cancer treatment, delivery of hydrophobic therapeutic drugs to tumor cells remains a major challenge in the field. To address these concerns, we have precisely engineered a new hyperbranched polymer for the targeted delivery of hydrophobic drugs by using a malonic acid-based A2B monomer and 1,6-hexanediol. The choice of monomer systems in our design allows for the formation of higher molecular weight polymers with hydrophobic cavities for the efficient encapsulation of therapeutic drugs that exhibit poor water solubility. Using several experimental techniques such as NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform-infrared (FT-IR), and gel permeation chromatography (GPC), the synthesized polymer was characterized, which indicated its dendritic structure, thermal stability, and amorphous nature, making it suitable as a drug delivery system. Following characterizations, theranostic nanoplatforms were formulated using a one-pot solvent diffusion method to coencapsulate hydrophobic drugs, BQU57 and doxorubicin. To achieve targeted delivery of loaded therapeutic drugs in A549 cancer cells, the surface of the polymeric nanoparticle was conjugated with folic acid. The therapeutic efficacy of the delivery system was determined by various cell-based in vitro experiments, including cytotoxicity, cell internalizations, reactive oxygen species (ROS), apoptosis, migration, and comet assays. Overall, findings from this study indicate that the synthesized dendritic polymer is a promising carrier for hydrophobic anticancer drugs with higher biocompatibility, stability, and therapeutic efficacy for applications in cancer therapy.

Advancements in technology for characterizing the tumor immune microenvironment

Immunotherapy plays a key role in cancer treatment, however, responses are limited to a small number of patients. The biological basis for the success of immunotherapy is the complex interaction between tumor cells and tumor immune microenvironment (TIME). Historically, research on tumor immune constitution was limited to the analysis of one or two markers, more novel technologies are needed to interpret the complex interactions between tumor cells and TIME. In recent years, major advances have already been made in depicting TIME at a considerably elevated degree of throughput, dimensionality and resolution, allowing dozens of markers to be labeled simultaneously, and analyzing the heterogeneity of tumour-immune infiltrates in detail at the single cell level, depicting the spatial landscape of the entire microenvironment, as well as applying artificial intelligence (AI) to interpret a large amount of complex data from TIME. In this review, we summarized emerging technologies that have made contributions to the field of TIME, and provided prospects for future research.

Facile one-pot hydrothermal synthesis of a zinc oxide/curcumin nanocomposite with enhanced toxic activity against breast cancer cells

Zinc oxide/Curcumin (Zn(CUR)O) nanocomposites were prepared via hydrothermal treatment of Zn(NO3)2 in the presence of hexamethylenetetramine as a stabilizing agent and CUR as a bioactive element. Three ZnO : CUR ratios were investigated, namely 57 : 43 (Zn(CUR)O-A), 60 : 40 (Zn(CUR)O-B) and 81 : 19 (Zn(CUR)O-C), as assessed by thermogravimetric analyses, with an average hydrodynamic diameter of nanoaggregates in the range of 223 to 361 nm. The interaction of CUR with ZnO via hydroxyl and ketoenol groups (as proved by X-ray photoelectron spectroscopy analyses) was found to significantly modify the key properties of ZnO nanoparticles with the obtainment of a bilobed shape (as shown by scanning electron microscopy), and influenced the growth process of the composite nanoparticles as indicated by the varying particle sizes determined by powder X-ray diffraction. The efficacy of Zn(CUR)O as anticancer agents was evaluated on MCF-7 and MDA-MB-231 cancer cells, obtaining a synergistic activity with a cell viability depending on the CUR amount within the nanocomposite. Finally, the determination of reactive oxygen species production in the presence of Zn(CUR)O was used as a preliminary evaluation of the mechanism of action of the nanocomposites.

Nanotechnology revolutionises breast cancer treatment: harnessing lipid-based nanocarriers to combat cancer cells

One of the most common cancers that occur in females is breast cancer. Despite the significant leaps and bounds that have been made in treatment of breast cancer, the disease remains one of the leading causes of death among women and a major public health challenge. The therapeutic efficacy of chemotherapeutics is hindered by chemoresistance and toxicity. Nano-based lipid drug delivery systems offer controlled drug release, nanometric size and site-specific targeting. Breast cancer treatment includes surgery, chemotherapy and radiotherapy. Despite this, no single method of treatment for the condition is currently effective due to cancer stem cell metastasis and chemo-resistance. Therefore, the employment of nanocarrier systems is necessary in order to target breast cancer stem cells. This article addresses breast cancer treatment options, including modern treatment procedures such as chemotherapy, etc. and some innovative therapeutic options highlighting the role of lipidic nanocarriers loaded with chemotherapeutic drugs such as nanoemulsion, solid-lipid nanoparticles, nanostructured lipid carriers and liposomes, and their investigations have demonstrated that they can limit cancer cell growth, reduce the risk of recurrence, as well as minimise post-chemotherapy metastasis. This article also explores FDA-approved lipid-based nanocarriers, commercially available formulations, and ligand-based formulations that are being considered for further research.

The Application of Nanotechnology and Nanomaterials in Cancer Diagnosis and Treatment: A Review

Cancer is one of the deadliest diseases worldwide in present times, with its incidence on a tremendous rise. It is caused by uncontrolled cell growth. Cancer therapies have advanced substantially, but there is a need for improvement in specificity and fear of systemic toxicity. Early detection is critical in improving patients' prognosis and quality of life, and recent advancements in technology, especially in dealing with biomaterials, have aided in that surge. Nanotechnology possesses the key to solving many of the downsides of traditional pharmaceutical formulations. Indeed, significant progress has been made in using customized nanomaterials for cancer diagnosis and treatment with high specificity, sensitivity, and efficacy. Nanotechnology is the integration of nanoscience into medicine by the use of nanoparticles. The advent of nanoscience in cancer diagnosis and treatment will help clinicians better assess and manage patients and improve the healthcare system and services. This review article gives an account of the clinical applications of nanoscience in the modern management of cancer, the different modalities of nanotechnology used, and the limitations and possible side effects of this new tool.

Quantum dots against SARS-CoV-2: diagnostic and therapeutic potentials

The application of quantum dots (QDs) for detecting and treating various types of coronaviruses is very promising, as their low toxicity and high surface performance make them superior among other nanomaterials; in conjugation with fluorescent probes they are promising semiconductor nanomaterials for the detection of various cellular processes and viral infections. In view of the successful results for inhibiting SARS-CoV-2, functional QDs could serve eminent role in the growth of safe nanotherapy for the cure of viral infections in the near future; their large surface areas help bind numerous molecules post-synthetically. Functionalized QDs with high functionality, targeted selectivity, stability and less cytotoxicity can be employed for highly sensitive co-delivery and imaging/diagnosis. Besides, due to the importance of safety and toxicity issues, QDs prepared from plant sources (e.g. curcumin) are much more attractive, as they provide good biocompatibility and low toxicity. In this review, the recent developments pertaining to the diagnostic and inhibitory potentials of QDs against SARS-CoV-2 are deliberated including important challenges and future outlooks. © 2022 Society of Chemical Industry (SCI).

Ferritin: A Promising Nanoreactor and Nanocarrier for Bionanotechnology

The essence of bionanotechnology lies in the application of nanotechnology/nanomaterials to solve the biological problems. Quantum dots and nanoparticles hold potential biomedical applications, but their inherent problems such as low solubility and associated toxicity due to their interactions at nonspecific target sites is a major concern. The self-assembled, thermostable, ferritin protein nanocages possessing natural iron scavenging ability have emerged as a potential solution to all the above-mentioned problems by acting as nanoreactor and nanocarrier. Ferritins, the cellular iron repositories, are hollow, spherical, symmetric multimeric protein nanocages, which sequester the excess of free Fe(II) and synthesize iron biominerals (Fe₂O₃·H₂O) inside their ∼5-8 nm central cavity. The electrostatics and dynamics of the pore residues not only drives the natural substrate Fe²⁺ inside ferritin nanocages but also uptakes a set of other metals ions/counterions during in vitro synthesis of nanomaterial. The current review aims to report the recent developments/understanding on ferritin structure (self-assembly, surface/pores electrostatics, metal ion binding sites) and chemistry occurring inside these supramolecular protein cages (protein mediated metal ion uptake and mineralization/nanoparticle formation) along with its surface modification to exploit them for various nanobiotechnological applications. Furthermore, a better understanding of ferritin self-assembly would be highly useful for optimizing the incorporation of nanomaterials via the disassembly/reassembly approach. Several studies have reported the successful engineering of these ferritin protein nanocages in order to utilize them as potential nanoreactor for synthesizing/incorporating nanoparticles and as nanocarrier for delivering imaging agents/drugs at cell specific target sites. Therefore, the combination of nanoscience (nanomaterials) and bioscience (ferritin protein) projects several benefits for various applications ranging from electronics to medicine.

Nanotechnology in the development of small and large molecule tyrosine kinase inhibitors and immunotherapy for the treatment of HER2-positive breast cancer

The HER2 receptor tyrosine kinase is a member of the epidermal growth factor receptor family which includes EGFR, HER3 and HER4. They are known to play critical roles in both normal development and cancer. A subset of breast cancers is associated with the HER2 gene, which is amplified and/or overexpressed in 20-25% of invasive breast cancers and is correlated with tumor resistance to chemotherapy, Metastatic Breast Cancer (MBC) and poor patient survival. The advent of receptor tyrosine kinase inhibitors has improved the prognosis of HER2-postive breast cancers; however, HER2+MBC invariably progresses (acquired resistance or de novo resistance). The monoclonal antibody-based drugs (large molecule TKIs) target the extracellular binding domain of HER2; while the small molecule TKIs act intracellularly to inhibit proliferation and survival signals. We reviewed the modes of action of the TKIs with a view to showing which of the TKIs could be combined in nanoparticles to benefit from the power of nanotechnology (reduced toxicity, improved solubility of hydrophobic drugs, long circulation half-lives, circumventing efflux pumps and preventing capture by the reticuloendothelial system (mononuclear phagocyte system). Nanotherapeutics also mediate the synchronization of the pharmacokinetics and biodistribution of multiple drugs incorporated in the nanoparticles. Novel TKIs that are currently under investigation with or without nanoparticle delivery are mentioned, and nano-based strategies to improve their delivery are suggested. Immunotherapies currently in clinical practice, clinical trials or at the preclinical stage are discussed. However, immunotherapy only works well in relatively small subsets of patients. Combining nanomedicine with immunotherapy can boost therapeutic outcomes, by turning "cold" non-immunoresponsive tumors and metastases into "hot" immunoresponsive lesions.

Nanotechnology in Colorectal Cancer for Precision Diagnosis and Therapy

Colorectal cancer (CRC) is the third most frequently occurring tumor in the human population. CRCs are usually adenocarcinomatous and originate as a polyp on the inner wall of the colon or rectum which may become malignant in the due course of time. Although the therapeutic options of CRC are limited, the early diagnosis of CRC may play an important role in preventive and therapeutic interventions to decrease the mortality rate. The CRC-affected tissues exhibit several molecular markers that may be exploited as the novel strategy to develop newer approaches for the treatment of the disease. Nanotechnology consists of a wide array of innovative and astonishing nanomaterials with both diagnostics and therapeutic potential. Several nanomaterials and nano formulations such as Carbon nanotubes, Dendrimer, Liposomes, Silica Nanoparticles, Gold nanoparticles, Metal-organic frameworks, Core-shell polymeric nano-formulations, Nano-emulsion System, etc can be used to targeted anticancer drug delivery and diagnostic purposes in CRC. The light-sensitive photosensitizer drugs loaded gold and silica nanoparticles can be used to diagnose as well as the killing of CRC cells by the targeted delivery of anticancer drugs to cancer cells. This review is focused on the recent advancement of nanotechnology in the diagnosis and treatment of CRC.

Gene Expression and Transcriptome Profiling of Changes in a Cancer Cell Line Post-Exposure to Cadmium Telluride Quantum Dots: Possible Implications in Oncogenesis

Cadmium telluride quantum dots (CdTe-QDs) are acquiring great interest in terms of their applications in biomedical sciences. Despite earlier sporadic studies on possible oncogenic roles and anticancer properties of CdTe-QDs, there is limited information regarding the oncogenic potential of CdTe-QDs in cancer progression. Here, we investigated the oncogenic effects of CdTe-QDs on the gene expression profiles of Chang cancer cells. Chang cancer cells were treated with 2 different doses of CdTe-QDs (10 and 25 μg/ml) at different time intervals (6, 12, and 24 h). Functional annotations helped identify the gene expression profile in terms of its biological process, canonical pathways, and gene interaction networks activated. It was found that the gene expression profiles varied in a time and dose-dependent manner. Validation of transcriptional changes of several genes through quantitative PCR showed that several genes upregulated by CdTe-QD exposure were somewhat linked with oncogenesis. CdTe-QD-triggered functional pathways that appear to associate with gene expression, cell proliferation, migration, adhesion, cell-cycle progression, signal transduction, and metabolism. Overall, CdTe-QD exposure led to changes in the gene expression profiles of the Chang cancer cells, highlighting that this nanoparticle can further drive oncogenesis and cancer progression, a finding that indicates the merit of immediate in vivo investigation.

Nanotechnology-Based Strategies to Evaluate and Counteract Cancer Metastasis and Neoangiogenesis

Cancer metastasis is the major cause of cancer-related morbidity and mortality. It represents one of the greatest challenges in cancer therapy, both because of the ability of metastatic cells to spread into different organs, and because of the consequent heterogeneity that characterizes primary and metastatic tumors. Nanomaterials can potentially be used as targeting or detection agents owing to unique chemical and physical features that allow tailored and tunable theranostic functions. This review highlights nanomaterial-based approaches in the detection and treatment of cancer metastasis, with a special focus on the evaluation of nanostructure effects on cell migration, invasion, and angiogenesis in the tumor microenvironment.

Can Carbon Quantum Dots (CQDs) or Boron Compounds be an Ultimate Solution for COVID-19 Therapy?

Severe acute respiratory syndrome (SARS) is an infectious and highly transmissible disease that is affected by SARS coronavirus (SARS-CoV) and for which there are presently no approved treatments. COVID-19 is a new strain of coronavirus that has not been previously identified in humans. It is also a member of the coronaviruse family and known to cause similar illnesses in humans. The last outbreak has been identified as a Pandemic because of COVID-19 infections in humans. This review has been prepared to give some information to readers or scientists about some new generation of boron-doped or boron attached composite quantum dots during the design phase of the drug or drug delivery systems to be developed to combat COVID-19 and to help in the design of new drugs and systems by opening some new horizons. All scientists and researchers must quickly share their ideas and experiences in the fight against COVID-19 to find a better therapy or strategy for humans, and thus we can be successful. In this sense, this review offers readers some new ideas and rational perspectives. In conclusion, boron-containing composite carbon quantum dots appear to be the most suitable delivery system for treating COVID-19 infections especially when they are delivered through the lung.

Emerging Nanopharmaceuticals and Nanonutraceuticals in Cancer Management

Nanotechnology is the science of nanoscale, which is the scale of nanometers or one billionth of a meter. Nanotechnology encompasses a broad range of technologies, materials, and manufacturing processes that are used to design and/or enhance many products, including medicinal products. This technology has achieved considerable progress in the oncology field in recent years. Most chemotherapeutic agents are not specific to the cancer cells they are intended to treat, and they can harm healthy cells, leading to numerous adverse effects. Due to this non-specific targeting, it is not feasible to administer high doses that may harm healthy cells. Moreover, low doses can cause cancer cells to acquire resistance, thus making them hard to kill. A solution that could potentially enhance drug targeting and delivery lies in understanding the complexity of nanotechnology. Engineering pharmaceutical and natural products into nano-products can enhance the diagnosis and treatment of cancer. Novel nano-formulations such as liposomes, polymeric micelles, dendrimers, quantum dots, nano-suspensions, and gold nanoparticles have been shown to enhance the delivery of drugs. Improved delivery of chemotherapeutic agents targets cancer cells rather than healthy cells, thereby preventing undesirable side effects and decreasing chemotherapeutic drug resistance. Nanotechnology has also revolutionized cancer diagnosis by using nanotechnology-based imaging contrast agents that can specifically target and therefore enhance tumor detection. In addition to the delivery of drugs, nanotechnology can be used to deliver nutraceuticals like phytochemicals that have multiple properties, such as antioxidant activity, that protect cells from oxidative damage and reduce the risk of cancer. There have been multiple advancements and implications for the use of nanotechnology to enhance the delivery of both pharmaceutical and nutraceutical products in cancer prevention, diagnosis, and treatment.

Functionalized Graphene Oxide for Chemotherapeutic Drug Delivery and Cancer Treatment: A Promising Material in Nanomedicine

The usage of nanomaterials for cancer treatment has been a popular research focus over the past decade. Nanomaterials, including polymeric nanomaterials, metal nanoparticles, semiconductor quantum dots, and carbon-based nanomaterials such as graphene oxide (GO), have been used for cancer cell imaging, chemotherapeutic drug targeting, chemotherapy, photothermal therapy, and photodynamic therapy. In this review, we discuss the concept of targeted nanoparticles in cancer therapy and summarize the in vivo biocompatibility of graphene-based nanomaterials. Specifically, we discuss in detail the chemistry and properties of GO and provide a comprehensive review of functionalized GO and GO-metal nanoparticle composites in nanomedicine involving anticancer drug delivery and cancer treatment.

Bone Morphogenetic Protein-2 Conjugated to Quantum Dot®s is Biologically Functional

Quantum Dot^®s (QDot^®s) are novel, semi-conductive nanostructures that emit a certain fluorescence when excited by specific wavelengths. QDot^®s are more photostable, brighter, and photobleach less than other fluorescent dyes. These characteristics give them the potential to be used in many biological applications. The shells of QDot^®s are coated with functional groups, such as carboxylate and organic groups, allowing them to couple to peptides/proteins and be used for real-time imaging and high-resolution microscopy. Here, we utilize Quantum Dot^®s and Bone Morphogenetic Protein-2 (BMP-2) to create a BMP-2-QDot^®s conjugate. BMP-2 is a growth factor that drives many processes such as cardiogenesis, neural growth, and osteogenesis. Despite its numerous roles, the trafficking and uptake of BMP-2 into cells is not well-established, especially during progression of diseases. The results presented here demonstrate for the first time a fluorescent BMP-2 analog that binds to the BMP-receptors (BMPRs), remains biologically active, and is stable for long time periods. Previous attempts to develop a biological BMP-2 analog with Fluorescein isothiocyanate (FITC) or nanodiamonds lacked data on the analog’s stability. Furthermore, these analogs did not address whether they can signal within the cell by binding to the BMPRs or were mediated by non-stable conjugates.

Shell-Free Copper Indium Sulfide Quantum Dots Induce Toxicity in Vitro and in Vivo

Semiconductor quantum dots (QDs) are attractive fluorescent contrast agents for in vivo imaging due to their superior photophysical properties, but traditional QDs comprise toxic materials such as cadmium or lead. Copper indium sulfide (CuInS₂, CIS) QDs have been posited as a nontoxic and potentially clinically translatable alternative; however, previous in vivo studies utilized particles with a passivating zinc sulfide (ZnS) shell, limiting direct evidence of the biocompatibility of the underlying CIS. For the first time, we assess the biodistribution and toxicity of unshelled CIS and partially zinc-alloyed CISZ QDs in a murine model. We show that bare CIS QDs breakdown quickly, inducing significant toxicity as seen in organ weight, blood chemistry, and histology. CISZ demonstrates significant, but lower, toxicity compared to bare CIS, while our measurements of core/shell CIS/ZnS are consistent with literature reports of general biocompatibility. In vitro cytotoxicity is dose-dependent on the amount of metal released due to particle degradation, linking degradation to toxicity. These results challenge the assumption that removing heavy metals necessarily reduces toxicity: indeed, we find comparable in vitro cytotoxicity between CIS and CdSe QDs, while CIS caused severe toxicity in vivo compared to CdSe. In addition to highlighting the complexity of nanotoxicity and the differences between the in vitro and in vivo outcomes, these unexpected results serve as a reminder of the importance of assessing the biocompatibility of core QDs absent the protective ZnS shell when making specific claims of compositional biocompatibility.

Nanocarriers as Magic Bullets in the Treatment of Leukemia

Leukemia is a type of hematopoietic stem/progenitor cell malignancy characterized by the accumulation of immature cells in the blood and bone marrow. Treatment strategies mainly rely on the administration of chemotherapeutic agents, which, unfortunately, are known for their high toxicity and side effects. The concept of targeted therapy as magic bullet was introduced by Paul Erlich about 100 years ago, to inspire new therapies able to tackle the disadvantages of chemotherapeutic agents. Currently, nanoparticles are considered viable options in the treatment of different types of cancer, including leukemia. The main advantages associated with the use of these nanocarriers summarized as follows: i) they may be designed to target leukemic cells selectively; ii) they invariably enhance bioavailability and blood circulation half-life; iii) their mode of action is expected to reduce side effects. FDA approval of many nanocarriers for treatment of relapsed or refractory leukemia and the desired results extend their application in clinics. In the present review, different types of nanocarriers, their capability in targeting leukemic cells, and the latest preclinical and clinical data are discussed.

Targeting Integrins in Cancer Nanomedicine: Applications in Cancer Diagnosis and Therapy

Due to advancements in nanotechnology, the application of nanosized materials (nanomaterials) in cancer diagnostics and therapeutics has become a leading area in cancer research. The decoration of nanomaterial surfaces with biological ligands is a major strategy for directing the actions of nanomaterials specifically to cancer cells. These ligands can bind to specific receptors on the cell surface and enable nanomaterials to actively target cancer cells. Integrins are one of the cell surface receptors that regulate the communication between cells and their microenvironment. Several integrins are overexpressed in many types of cancer cells and the tumor microvasculature and function in the mediation of various cellular events. Therefore, the surface modification of nanomaterials with integrin-specific ligands not only increases their binding affinity to cancer cells but also enhances the cellular uptake of nanomaterials through the intracellular trafficking of integrins. Moreover, the integrin-specific ligands themselves interfere with cancer migration and invasion by interacting with integrins, and this finding provides a novel direction for new treatment approaches in cancer nanomedicine. This article reviews the integrin-specific ligands that have been used in cancer nanomedicine and provides an overview of the recent progress in cancer diagnostics and therapeutic strategies involving the use of integrin-targeted nanomaterials.

Immunotoxicity Considerations for Next Generation Cancer Nanomedicines

Although interest and funding in nanotechnology for oncological applications is thriving, translating these novel therapeutics through the earliest stages of preclinical assessment remains challenging. Upon intravenous administration, nanomaterials interact with constituents of the blood inducing a wide range of associated immunotoxic effects. The literature on the immunological interactions of nanomaterials is vast and complicated. A small change in a particular characteristic of a nanomaterial (e.g., size, shape, or charge) can have a significant effect on its immunological profile in vivo, and poor selection of specific assays for establishing these undesirable effects can overlook this issue until the latest stages of preclinical assessment. This work describes the current literature on unintentional immunological effects associated with promising cancer nanomaterials (liposomes, dendrimers, mesoporous silica, iron oxide, gold, and quantum dots) and puts focus on what is missing in current preclinical evaluations. Opportunities for avoiding or limiting immunotoxicity through efficient preclinical assessment are discussed, with an emphasis placed on current regulatory views and requirements. Careful consideration of these issues will ensure a more efficient preclinical assessment of cancer nanomedicines, enabling a smoother clinical translation with less failures in the future.

CaCO3 as an Environmentally Friendly Renewable Material for Drug Delivery Systems: Uptake of HSA-CaCO3 Nanocrystals Conjugates in Cancer Cell Lines

Chemical and biochemical functionalization of nanoparticles (NPs) can lead to an active cellular uptake enhancing their efficacy thanks to the targeted localization in tumors. In the present study calcium carbonate nano-crystals (CCNs), stabilized by an alcohol dehydration method, were successfully modified by grafting human serum albumin (HSA) on the surface to obtain a pure protein corona. Two types of CCNs were used: naked CaCO3 and the (3-aminopropyl)triethoxysilane (APTES) modified CaCO3-NH2. The HSA conjugation with naked CCN and amino-functionalized CCN (CCN-NH2) was established through the investigation of modification in size, zeta potential, and morphology by Transmission Electron Microscopy (TEM). The amount of HSA coating on the CCNs surface was assessed by spectrophotometry. Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) confirmed the grafting of APTES to the surface and successive adsorption of HSA. Furthermore, to evaluate the effect of protein complexation of CCNs on cellular behavior, bioavailability, and biological responses, three human model cancer cell lines, breast cancer (MCF7), cervical cancer (HeLa), and colon carcinoma (Caco-2) were selected to characterize the internalization kinetics, localization, and bio-interaction of the protein-enclosed CCNs. To monitor internalization of the various conjugates, chemical modification with fluorescein-isothiocyanate (FITC) was performed, and their stability over time was measured. Confocal microscopy was used to probe the uptake and confirm localization in the perinuclear region of the cancer cells. Flow cytometry assays confirmed that the bio-functionalization influence cellular uptake and the CCNs behavior depends on both cell line and surface features.

Encapsulation of Gold Nanorods with Porphyrins for the Potential Treatment of Cancer and Bacterial Diseases: A Critical Review

Cancer and bacterial diseases have been the most incidental diseases to date. According to the World Health Report 2018, at least every family is affected by cancer around the world. In 2012, 14.1 million people were affected by cancer, and that figure is bound to increase to 21.6 million in 2030. Medicine therefore sorts out ways of treatment using conventional methods which have been proven to have many side effects. Researchers developed photothermal and photodynamic methods to treat both cancer and bacterial diseases. These methods pose fewer effects on the biological systems but still no perfect method has been synthesized. The review serves to explore porphyrin and gold nanorods to be used in the treatment of cancer and bacterial diseases: porphyrins as photosensitizers and gold nanorods as delivery agents. In addition, the review delves into ways of incorporating photothermal and photodynamic therapy aimed at producing a less toxic, more efficacious, and specific compound for the treatment.

State-of-the-Art of Profiling Immune Contexture in the Era of Multiplexed Staining and Digital Analysis to Study Paraffin Tumor Tissues

Multiplexed platforms for multiple epitope detection have emerged in the last years as very powerful tools to study tumor tissues. These revolutionary technologies provide important visual techniques for tumor examination in formalin-fixed paraffin-embedded specimens to improve the understanding of the tumor microenvironment, promote new treatment discoveries, aid in cancer prevention, as well as allowing translational studies to be carried out. The aim of this review is to highlight the more recent methodologies that use multiplexed staining to study simultaneous protein identification in formalin-fixed paraffin-embedded tumor tissues for immune profiling, clinical research, and potential translational analysis. New multiplexed methodologies, which permit the identification of several proteins at the same time in one single tissue section, have been developed in recent years with the ability to study different cell populations, cells by cells, and their spatial distribution in different tumor specimens including whole sections, core needle biopsies, and tissue microarrays. Multiplexed technologies associated with image analysis software can be performed with a high-quality throughput assay to study cancer specimens and are important tools for new discoveries. The different multiplexed technologies described in this review have shown their utility in the study of cancer tissues and their advantages for translational research studies and application in cancer prevention and treatments.

Quantum Dot Based Nano-Biosensors for Detection of Circulating Cell Free miRNAs in Lung Carcinogenesis: From Biology to Clinical Translation

Lung cancer is the most frequently occurring malignancy and the leading cause of cancer-related death for men in our country. The only recommended screening method is clinic based low-dose computed tomography (also called a low-dose CT scan, or LDCT). However, the effect of LDCT on overall mortality observed in lung cancer patients is not statistically significant. Over-diagnosis, excessive cost, risks associated with radiation exposure, false positive results and delay in the commencement of the treatment procedure questions the use of LDCT as a reliable technique for population-based screening. Therefore, identification of minimal-invasive biomarkers able to detect malignancies at an early stage might be useful to reduce the disease burden. Circulating nucleic acids are emerging as important source of information for several chronic pathologies including lung cancer. Of these, circulating cell free miRNAs are reported to be closely associated with the clinical outcome of lung cancer patients. Smaller size, sequence homology between species, low concentration and stability are some of the major challenges involved in characterization and specific detection of miRNAs. To circumvent these problems, synthesis of a quantum dot based nano-biosensor might assist in sensitive, specific and cost-effective detection of differentially regulated miRNAs. The wide excitation and narrow emission spectra of these nanoparticles result in excellent fluorescent quantum yields with a broader color spectrum which make them ideal bio-entities for fluorescence resonance energy transfer (FRET) based detection for sequential or simultaneous study of multiple targets. In addition, photo-resistance and higher stability of these nanoparticles allows extensive exposure and offer state-of-the art sensitivity for miRNA targeting. A major obstacle for integrating QDs into clinical application is the QD-associated toxicity. However, the use of non-toxic shells along with surface modification not only overcomes the toxicity issues, but also increases the ability of QDs to quickly detect circulating cell free miRNAs in a non-invasive mode. The present review illustrates the importance of circulating miRNAs in lung cancer diagnosis and highlights the translational prospects of developing QD-based nano-biosensor for rapid early disease detection.

Biomimetic quantum dot-labeled B16F10 murine melanoma cells as a tool to monitor early steps of lung metastasis by in vivo imaging

Background

Numerous studies have proposed the use of fluorescent semiconductor nanoparticles or quantum dots (QDs) as novel tools to label cells and tumors. However, QD applications are limited by their toxicity in biological systems and little is known about whether QDs affect the capacity of cancer cells to metastasize. Previously, we described the “biomimetic” synthesis of CdTe-QDs (QDs-glutathione [GSH]) with increased biocompatibility and the potential utility in labeling cells.

Purpose

In order to determine the feasibility of using QDs-GSH as a tool for tracking tumor cells during early metastasis, we characterized here for the first time, the in vitro and in vivo effects of the incorporation of green or red biomimetic QDs-GSH into B16F10 cells, a syngeneic mouse melanoma line for metastasis assays in C57BL/6 mice.

Methods

B16F10 cells were labeled with green or red biomimetic QDs-GSH in the presence or absence of n-acetylcysteine. Then, migration, invasion and proliferation of labeled B16F10 were evaluated in vitro. Finally, the B16F10 cells labeled with red QDs-GSH were used to monitor in vivo lung metastasis at early time points (5 minutes to 24 hours) or after 21 days in C57BL/6 mice.

Results

We developed a methodology that allows obtaining QDs-GSH-labeled B16F10 cells (nearly 100% viable labeled cells), which remained viable for at least 5 days and migrated similarly to control cells. However, proliferation, invasion, and the capacity to form metastatic nodules in the lungs were severely attenuated. Fluorescence imaging revealed that distribution/accumulation of QDs-GSH-labeled B16F10 cells could be tracked following injection into C57BL/6 mice (syngeneic preclinical metastasis model) and that these cells preferentially accumulated in the perialveolar area in lungs as early as 5 minutes post-injection.

Conclusion

The methodology described here represents a useful alternative for monitoring initial events during tumor cell metastasis.

Cellular toxicity of silicon carbide nanomaterials as a function of morphology

Silicon carbide has been shown to be biocompatible and is used as a coating material for implanted medical devices to prevent biofilms. Silicon carbide nanomaterials are also promising in cell tracking due to their stable and strong luminescence, but more comprehensive studies of this material on the nanoscale are needed. Here, we studied the toxicity of silicon carbide nanomaterials on human mesenchymal stem cells in terms of metabolism, viability, adhesion, proliferation, migration, oxidative stress, and differentiation ability. We compared two different shapes and found that silicon carbide nanowires are toxic to human mesenchymal stem cells but not to cancer cell lines at the concentration of 0.1 mg/mL. Control silicon carbide nanoparticles were biocompatible to human mesenchymal stem cells at 0.1 mg/mL. We studied the potential mechanistic effect of silicon carbide nanowires on human mesenchymal stem cells' phenotype, cytokine secretion, and gene expression. These findings suggest that the toxic effect of silicon carbide nanomaterials to human mesenchymal stem cells are dependent on morphology.

Trends towards Biomimicry in Theranostics

Over the years, imaging and therapeutic modalities have seen considerable progress as a result of advances in nanotechnology. Theranostics, or the marrying of diagnostics and therapy, has increasingly been employing nano-based approaches to treat cancer. While first-generation nanoparticles offered considerable promise in the imaging and treatment of cancer, toxicity and non-specific distribution hindered their true potential. More recently, multistage nanovectors have been strategically designed to shield and carry a payload to its intended site. However, detection by the immune system and sequestration by filtration organs (i.e., liver and spleen) remains a major obstacle. In an effort to circumvent these biological barriers, recent trends have taken inspiration from biology. These bioinspired approaches often involve the use of biologically-derived cellular components in the design and fabrication of biomimetic nanoparticles. In this review, we provide insight into early nanoparticles and how they have steadily evolved to include bioinspired approaches to increase their theranostic potential.

Toxicological status of nanoparticles: What we know and what we don't know

The field of nanotechnology has grown exponentially during the last few decades, due in part to the use of nanoparticles in many manufacturing processes, as well as their potential as clinical agents for treatment of diseases and for drug delivery. This has created several new avenues by which humans can be exposed to nanoparticles. Unfortunately, investigations assessing the toxicological impacts of nanoparticles (i.e. nanotoxicity), as well as their possible risks to human health and the environment, have not kept pace with the rapid rise in their use. This has created a gap-in-knowledge and a substantial need for more research. Studies are needed to help complete our understanding of the mechanisms of toxicity of nanoparticles, as well as the mechanisms mediating their distribution and accumulation in cells and tissues and their elimination from the body. This review summarizes our knowledge on nanoparticles, including their various applications, routes of exposure, their potential toxicity and risks to human health.

Noninvasive Biomarkers of Colorectal Cancer: Role in Diagnosis and Personalised Treatment Perspectives

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. It has been estimated that more than one-third of patients are diagnosed when CRC has already spread to the lymph nodes. One out of five patients is diagnosed with metastatic CRC. The stage of diagnosis influences treatment outcome and survival. Notwithstanding the recent advances in multidisciplinary management and treatment of CRC, patients are still reluctant to undergo screening tests because of the associated invasiveness and discomfort (e.g., colonoscopy with biopsies). Moreover, the serological markers currently used for diagnosis are not reliable and, even if they were useful to detect disease recurrence after treatment, they are not always detected in patients with CRC (e.g., CEA). Recently, translational research in CRC has produced a wide spectrum of potential biomarkers that could be useful for diagnosis, treatment, and follow-up of these patients. The aim of this review is to provide an overview of the newer noninvasive or minimally invasive biomarkers of CRC. Here, we discuss imaging and biomolecular diagnostics ranging from their potential usefulness to obtain early and less-invasive diagnosis to their potential implementation in the development of a bespoke treatment of CRC.

One-Pot Aqueous Synthesis of Fluorescent Ag-In-Zn-S Quantum Dot/Polymer Bioconjugates for Multiplex Optical Bioimaging of Glioblastoma Cells

Cancer research has experienced astonishing advances recently, but cancer remains a major threat because it is one of the leading causes of death worldwide. Glioblastoma (GBM) is the most malignant brain tumor, where the early diagnosis is vital for longer survival. Thus, this study reports the synthesis of novel water-dispersible ternary AgInS2 (AIS) and quaternary AgInS2-ZnS (ZAIS) fluorescent quantum dots using carboxymethylcellulose (CMC) as ligand for multiplexed bioimaging of malignant glioma cells (U-87 MG). Firstly, AgInS2 core was prepared using a one-pot aqueous synthesis stabilized by CMC at room temperature and physiological pH. Then, an outer layer of ZnS was grown and thermally annealed to improve their optical properties and split the emission range, leading to core-shell alloyed nanostructures. Their physicochemical and optical properties were characterized, demonstrating that luminescent monodispersed AIS and ZAIS QDs were produced with average sizes of 2.2 nm and 4.3 nm, respectively. Moreover, the results evidenced that they were cytocompatible using in vitro cell viability assays towards human embryonic kidney cell line (HEK 293T) and U-87 MG cells. These AIS and ZAIS successfully behaved as fluorescent nanoprobes (red and green, resp.) allowing multiplexed bioimaging and biolabeling of costained glioma cells using confocal microscopy.

Assessment of PI3K/AKT/PTEN signaling pathway activity in colorectal cancer using quantum dot-conjugated antibodies

In certain patients with advanced colorectal cancer, loss of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) activity is observed. PTEN is a major gatekeeper gene of the AKT serine/threonine kinase (AKT) signaling pathway responsible for the proliferative activity of cells. The assessment of AKT activity may be a prognostic factor or a predictor of response to the targeted therapies against particular signaling proteins. To precisely identify the cause and the place of the pathway deregulation, it is necessary to identify phosphorylation states and concentrations of several proteins located at different levels of the regulatory cascade. In the present study, we propose the simultaneous use of specific antibodies conjugated with different quantum dots to highlight the nature of AKT/PKB cascade deregulation in patients with colorectal cancer and the loss of PTEN expression in tumor tissue. Fifty patients with colorectal cancer of no specific location were enrolled in the study. The expression of the PTEN protein, and concentrations of phosphorylated/activated forms of 3-Phosphoinositide-dependent kinase 1 (PDK1) and AKT were assessed using quantum dot-conjugated antibodies. In patients with a diminished or complete loss of the PTEN expression in the tumor tissue increased levels of activated/phosphorylated forms of PDK1 (Phospho-PDK1-Ser241) and AKT (Phospho-AKT-Thr308) proteins were found, which are responsible for the permanent activation of the phosphoinositide 3-kinase/AKT/PTEN signaling pathway in certain cases of colorectal cancer.

Highly Specific and Sensitive Fluorescent Nanoprobes for Image-Guided Resection of Sub-Millimeter Peritoneal Tumors

A current challenge in the treatment of peritoneal carcinomatosis is the inability to detect, visualize, and resect small or microscopic tumors of pancreatic, ovarian, or mesothelial origin. In these diseases, the completeness of primary tumor resection is directly correlated with patient survival, and hence, identifying small sub-millimeter tumors (i.e., disseminated disease) is critical. Thus, new imaging techniques and probes are needed to improve cytoreductive surgery and patient outcomes. Highly fluorescent rhodamine-labeled expansile nanoparticles (HFR-eNPs) are described for use as a visual aid during cytoreductive surgery of pancreatic carcinomatosis. The covalent incorporation of rhodamine into ∼30 nm eNPs increases the fluorescent signal compared to free rhodamine, thereby affording a brighter and more effective probe than would be achieved by a single rhodamine molecule. Using the intraperitoneal route of administration, HFR-eNPs localize to regions of large (∼1 cm), sub-centimeter, and sub-millimeter intraperitoneal tumor in three different animal models, including pancreatic, mesothelioma, and ovarian carcinoma. Tumoral localization of the HFR-eNPs depends on both the material property (i.e., eNP polymer) as well as the surface chemistry (anionic surfactant vs PEGylated noncharged surfactant). In a rat model of pancreatic carcinomatosis, HFR-eNP identification of tumor is validated against gold-standard histopathological analysis to reveal that HFR-eNPs possess high specificity (99%) and sensitivity (92%) for tumors, in particular, sub-centimeter and microscopic sub-millimeter tumors, with an overall accuracy of 95%. Finally, as a proof-of-concept, HFR-eNPs are used to guide the resection of pancreatic tumors in a rat model of peritoneal carcinomatosis.

Advances in fluorescent-image guided surgery

Fluorescence imaging is increasingly gaining intraoperative applications. Here, we highlight a few recent advances in the surgical use of fluorescent probes.

Synthesis and Optical Properties of Novel Red-Emitting PbNb2O6: Eu(3+) Phosphors

Undoped and PbNb2O6:Eu(3+) (1.0 ≤ x ≤ 6.0 mol%) phosphors were synthesized at 1100 °C for 3.5 h by the conventional solid state reaction method. Synthesized PbNb2O6:Eu(3+) phosphors were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS) and Photoluminescence (PL) analyses. The PL spectra showed series of excitation peaks between 350 and 430 nm due to the 4f-4f transitions of Eu(3+). For 395.0 nm excitation, emission spectra of Eu(3+) doped samples were observed at 591 nm (orange) and 614 nm (red) due to the (5)D0 → (7)F1 transitions and (5)D0 → (7)F2 transitions, respectively. PL analysis results also showed that the emission intensity increased by increasing Eu(3+) ion content. No concentration quenching effect was observed. The CIE chromaticity color coordinates (x,y) of the PbNb2O6:Eu(3+) phosphors were found to be in the red region of the chromaticity diagram.

Co-evolution of tumor-associated macrophages and tumor neo-vessels during cervical cancer invasion

Considering the crucial significance of the tumor microenvironment in cancer development and progression, the present study aimed to investigate the changes in macrophages and angiogenesis during the cervical cancer (CC) progression process from chronic cervicitis to cervical intraepithelial neoplasia grades I-III (CIN I-III) to CC. This investigation included quantitative analysis and assessment of the spatial associations between tumor-associated macrophages (TAMs) and tumor neo-vessels. The conventional immunohistochemistry staining technique was used to detect cluster of differentiation (CD)68 and CD105 biomarker expression for TAMs and tumor neo-vessels, respectively. In addition, with the assistance of quantum dot (QD)-based two-component in situ imaging technology, the expression of the TAMs and tumor neo-vessels could be observed simultaneously. The quantitative analysis and co-evolution of the TAMs and tumor neo-vessels could then be processed. During the progression process from chronic cervicitis to cervical CIN I-III, and ultimately to invasive CC, the expression of the macrophages and neo-vessels in the tumor microenvironment increased synchronously. According to the quantitative analysis results, the median value of the TAM density was higher in the CC group (5,540.14) than in the CIN I-III group (2,502.17) and the chronic cervicitis group (1,403.31), with statistical significance in all three groups (P<0.001, for between-group comparisons). The number of neo-vessels was also much higher in the CC group (n=27) than in the CIN I-III group (n=17) or the chronic cervicitis group (n=6.5), with statistical significance in all three groups (P<0.001, for between-group comparisons). These findings demonstrated the great significance and close association of TAMs and tumor angiogenesis during CC development and progression. Thus, QDs-based in situ and simultaneous imaging of key cancer molecules may provide insights with regard to the biology of cancer invasion.

Recent insights into nanotechnology development for detection and treatment of colorectal cancer

The global incidence of colorectal cancer (CRC) is 1.3 million cases. It is the third most frequent cancer in males and females. Most CRCs are adenocarcinomas and often begin as a polyp on the inner wall of the rectum or colon. Some of these polyps become malignant, eventually. Detecting and removing these polyps in time can prevent CRC. Therefore, early diagnosis of CRC is advantageous for preventive and instant action interventions to decrease the mortality rates. Nanotechnology has been enhancing different methods for the detection and treatment of CRCs, and the research has provided hope within the scientific community for the development of new therapeutic strategies. This review presents the recent development of nanotechnology for the detection and treatment of CRC.

Evaluation of therapeutic effectiveness of 131I-antiEGFR-BSA-PCL in a mouse model of colorectal cancer

AIM: To investigate the biological effects of internal irradiation, and the therapeutic effectiveness was assessed of ¹³¹I-labeled anti-epidermal growth factor receptor (EGFR) liposomes, derived from cetuximab, when used as a tumor-targeting carrier in a colorectal cancer mouse model.

METHODS: We described the liposomes and characterized their EGFR-targeted binding and cellular uptake in EGFR-overexpressing LS180 colorectal cancer cells. After intra-tumor injections of 74 MBq (740 MBq/mL) ¹³¹I-antiEGFR-BSA-PCL, we investigated the biological effects of internal irradiation and the therapeutic efficacy of ¹³¹I-antiEGFR-BSA-PCL on colorectal cancer in a male BALB/c mouse model. Tumor size, body weight, histopathology, and SPECT imaging were monitored for 33 d post-therapy.

RESULTS: The rapid radioiodine uptake of ¹³¹I-antiEGFR-BSA-PCL and ¹³¹I-BSA-PCL reached maximum levels at 4 h after incubation, and the ¹³¹I uptake of ¹³¹I-antiEGFR-BSA-PCL was higher than that of ¹³¹I-BSA-PCL in vitro. The ¹³¹I tissue distribution assay revealed that ¹³¹I-antiEGFR-BSA-PCL was markedly taken up by the tumor. Furthermore, a tissue distribution assay revealed that ¹³¹I-antiEGFR-BSA-PCL was markedly taken up by the tumor and reached its maximal uptake value of 21.0 ± 1.01 %ID/g (%ID/g is the percentage injected dose per gram of tissue) at 72 h following therapy; the drug concentration in the tumor was higher than that in the liver, heart, colon, or spleen. Tumor size measurements showed that tumor development was significantly inhibited by treatments with ¹³¹I-antiEGFR-BSA-PCL and ¹³¹I-BSA-PCL. The volume of tumor increased, and treatment rate with ¹³¹I-antiEGFR-BSA-PCL was 124% ± 7%, lower than that with ¹³¹I-BSA-PCL (127% ± 9%), ¹³¹I (143% ± 7%), and normal saline (146% ± 10%). The percentage losses in original body weights were 39% ± 3%, 41% ± 4%, 49% ± 5%, and 55% ± 13%, respectively. The best survival and cure rates were obtained in the group treated with ¹³¹I-antiEGFR-BSA-PCL. The animals injected with ¹³¹I-antiEGFR-BSA-PCL and ¹³¹I-BSA-PCL showed more uniform focused liposome distribution within the tumor area.

CONCLUSION: This study demonstrated the potential beneficial application of ¹³¹I-antiEGFR-BSA-PCL for treating colorectal cancer. ¹³¹I-antiEGFR-BSA-PCL suppressed the development of xenografted colorectal cancer in nude mice, thereby providing a novel candidate for receptor-mediated targeted radiotherapy.

Dissecting the Factors Affecting the Fluorescence Stability of Quantum Dots in Live Cells

Labeling and imaging of live cells with quantum dots (QDs) has attracted great attention in the biomedical field over the past two decades. Maintenance of the fluorescence of QDs in a biological environment is crucial for performing long-term cell tracking to investigate the proliferation and functional evolution of cells. The cell-penetrating peptide transactivator of transcription (TAT) is a well-studied peptide to efficiently enhance the transmembrane delivery. Here, we used TAT peptide-conjugated QDs (TAT-QDs) as a model system to examine the fluorescence stability of QDs in live cells. By confocal microscopy, we found that TAT-QDs were internalized into cells by endocytosis, and transported into the cytoplasm via the mitochondria, Golgi apparatus, and lysosomes. More importantly, the fluorescence of TAT-QDs in live cells was decreased mainly by cell proliferation, and the low pH value in the lysosomes could also lower the fluorescence intensity of intracellular QDs. Quantitative analysis of the amount of QDs in the extracellular region and whole cells indicated that the exocytosis was not the primary cause of fluorescence decay of intracellular QDs. This work facilitates a better understanding of the fluorescence stability of QDs for cell imaging and long-term tracking in live cells. Also, it provides insights into the utility of TAT for transmembrane transportation, and the preparation and modification of QDs for cell imaging and tracking.

Materiomics for Oral Disease Diagnostics and Personal Health Monitoring: Designer Biomaterials for the Next Generation Biomarkers

We live in exciting times for a new generation of biomarkers being enabled by advances in the design and use of biomaterials for medical and clinical applications, from nano- to macro-materials, and protein to tissue. Key challenges arise, however, due to both scientific complexity and compatibility of the interface of biology and engineered materials. The linking of mechanisms across scales by using a materials science approach to provide structure-process-property relations characterizes the emerging field of 'materiomics,' which offers enormous promise to provide the hitherto missing tools for biomaterial development for clinical diagnostics and the next generation biomarker applications towards personal health monitoring. Put in other words, the emerging field of materiomics represents an essentially systematic approach to the investigation of biological material systems, integrating natural functions and processes with traditional materials science perspectives. Here we outline how materiomics provides a game-changing technology platform for disruptive innovation in biomaterial science to enable the design of tailored and functional biomaterials--particularly, the design and screening of DNA aptamers for targeting biomarkers related to oral diseases and oral health monitoring. Rigorous and complementary computational modeling and experimental techniques will provide an efficient means to develop new clinical technologies in silico, greatly accelerating the translation of materiomics-driven oral health diagnostics from concept to practice in the clinic.

Nanotechnology and Pediatric Cancer: Prevention, Diagnosis and Treatment

Despite development of new approaches for the treatment of cancer disease, it is the second cause of mortality in world. Annually, 30000 persons die in Iran due to cancer diseases. Eighty percent of cancer patients are children which about 50% children lead to death. Given the high rate of cancer-related death, the new approaches for prevention, control, early diagnosis, and treatment of this disease seem necessary. Investigation of new strategies is the major challenge for scientists at recent century. Nanotechnology as a new scientific field with novel and small compounds utilized different fields over the past ten years especially in medicine. This science has come to the forefront in the areas of medical diagnostics, imaging, and therapeutic scheduls. Therefore, it has the potential applications for cancer detection and therapy. This review will discuss the therapeutic applications of different nano-materials in diagnosis, imaging, and delivery of therapeutic agents for the treatment of cancer with a major focus on their applications for the treatment of cancer and cancer- related diseases in children. The advancements in established nanoparticle technologies such as liposomes, polymer micelles, and functionalization regarding tumor targeting and controlled release strategies as well as drug delivery were discussed. It will also review the blood toxicity of used nanostructures.

Nanotechnology Approaches for the Delivery of Exogenous siRNA for HIV Therapy

RNA interference (RNAi) is triggered by oligonucleotides that are about 21-23 nucleotides long and are capable of inducing the destruction of complementary mRNA. The RNAi technique has been successfully utilized to target HIV replication; however, the main limitation to the successful utilization of this technique in vivo is the inability of naked siRNA to cross the cell membrane by diffusion due to its strong anionic charge and large molecular weight. This review describes current nonviral nanotechnological approaches to deliver anti-HIV siRNAs for the treatment of HIV infection.

Carcinogenic activity of PbS quantum dots screened using exosomal biomarkers secreted from HEK293 cells

Lead sulfide (PbS) quantum dots (QDs) have been applied in the biomedical area because they offer an excellent platform for theragnostic applications. In order to comprehensively evaluate the biocompatibility of PbS QDs in human cells, we analyzed the exosomes secreted from cells because exosomes are released during cellular stress to convey signals to other cells and serve as a reservoir of enriched biomarkers. PbS QDs were synthesized and coated with 3-mercaptopropionic acid (MPA) to allow the particles to disperse in water. Exosomes were isolated from HEK293 cells treated with PbS-MPA at concentrations of 0 µg/mL, 5 µg/mL, and 50 µg/mL, and the exosomal expression levels of miRNAs and proteins were analyzed. As a result, five miRNAs and two proteins were proposed as specific exosomal biomarkers for the exposure of HEK293 cells to PbS-MPA. Based on the pathway analysis, the molecular signature of the exosomes suggested that PbS-MPA QDs had carcinogenic activity. The comet assay and expression of molecular markers, such as p53, interleukin (IL)-8, and C-X-C motif chemokine 5, indicated that DNA damage occurred in HEK293 cells following PbS-MPA exposure, which supported the carcinogenic activity of the particles. In addition, there was obvious intensification of miRNA expression signals in the exosomes compared with that of the parent cells, which suggested that exosomal biomarkers could be detected more sensitively than those of whole cellular extracts.

Quantum dots for quantitative imaging: from single molecules to tissue

Since their introduction to biological imaging, quantum dots (QDs) have progressed from a little known, but attractive, technology to one that has gained broad application in many areas of biology. The versatile properties of these fluorescent nanoparticles have allowed investigators to conduct biological studies with extended spatiotemporal capabilities that were previously not possible. In this review, we focus on QD applications that provide enhanced quantitative information concerning protein dynamics and localization, including single particle tracking and immunohistochemistry, and finish by examining the prospects of upcoming applications, such as correlative light and electron microscopy and super-resolution. Advances in single molecule imaging, including multi-color and three-dimensional QD tracking, have provided new insights into the mechanisms of cell signaling and protein trafficking. New forms of QD tracking in vivo have allowed the observation of biological processes at molecular level resolution in the physiological context of the whole animal. Further methodological development of multiplexed QD-based immunohistochemistry assays should enable more quantitative analysis of key proteins in tissue samples. These advances highlight the unique quantitative data sets that QDs can provide to further our understanding of biological and disease processes.

In vivo molecular imaging of colorectal cancer using quantum dots targeted to vascular endothelial growth factor receptor 2 and optical coherence tomography/laser-induced fluorescence dual-modality imaging

Optical coherence tomography/laser induced fluorescence (OCT/LIF) dual-modality imaging allows for minimally invasive, nondestructive endoscopic visualization of colorectal cancer in mice. This technology enables simultaneous longitudinal tracking of morphological (OCT) and biochemical (fluorescence) changes as colorectal cancer develops, compared to current methods of colorectal cancer screening in humans that rely on morphological changes alone. We have shown that QDot655 targeted to vascular endothelial growth factor receptor 2 (QD655-VEGFR2) can be applied to the colon of carcinogen-treated mice and provides significantly increased contrast between the diseased and undiseased tissue with high sensitivity and specificity ex vivo. QD655-VEGFR2 was used in a longitudinal in vivo study to investigate the ability to correlate fluorescence signal to tumor development. QD655-VEGFR2 was applied to the colon of azoxymethane (AOM-) or saline-treated control mice in vivo via lavage. OCT/LIF images of the distal colon were taken at five consecutive time points every three weeks after the final AOM injection. Difficulties in fully flushing unbound contrast agent from the colon led to variable background signal; however, a spatial correlation was found between tumors identified in OCT images, and high fluorescence intensity of the QD655 signal, demonstrating the ability to detect VEGFR2 expressing tumors in vivo.

Quantum dots targeted to vascular endothelial growth factor receptor 2 as a contrast agent for the detection of colorectal cancer

We successfully labeled colorectal cancer in vivo using quantum dots targeted to vascular endothelial growth factor receptor 2 (VEGFR2). Quantum dots with emission centered at 655 nm were bioconjugated to anti-VEGFR2 antibodies through streptavidin/biotin linking. The resulting QD655-VEGFR2 contrast agent was applied in vivo to the colon of azoxymethane (AOM) treated mice via lavage and allowed to incubate. The colons were then excised, cut longitudinally, opened to expose the lumen, and imaged en face using a fluorescence stereoscope. The QD655-VEGFR2 contrast agent produced a significant increase in contrast between diseased and undiseased tissues, allowing for fluorescence-based visualization of the diseased areas of the colon. Specificity was assessed by observing insignificant contrast increase when labeling colons of AOM-treated mice with quantum dots bioconjugated to isotype control antibodies, and by labeling the colons of saline-treated control mice. This contrast agent has a great potential for in vivo imaging of the colon through endoscopy.