In vitro and in vivo evaluation of anti-nucleolin-targeted magnetic PLGA nanoparticles loaded with doxorubicin as a theranostic agent for enhanced targeted cancer imaging and therapy

Optical and electrochemical-based nano-aptasensing approaches for the detection of circulating tumor cells (CTCs)

More recently, detection of circulating tumor cells (CTCs) has been considered as an appealing prognostic and diagnostic approach for cancer patients. CTCs as a type of tumor-derived cells are secreted by the tumor and released into the blood circulation. Since the migration of CTCs is an early event in cancer progression, patients who still have tumor-free lymph nodes have to be well examined for the CTCs presence in their blood circulation. Nowadays, there is a broad range of detection methods available to identify CTCs. As artificial RNA oligonucleotides or single-stranded DNA with receptor and catalytic characteristics, aptamers have been standing out, owing to their target-induced conformational modifications, elevated stability, and target specificity to be implemented in biosensing techniques. To date, several sensitivity-enhancement methods alongside smart nanomaterials have been used for the creation of new aptasensors to address the limit of detection (LOD), and improve the sensitivity of numerous analyte identification methods. The present review article supports a focused overview of the recent studies in the identification and quantitative determination of CTCs by aptamer-based biosensors and nanobiosensors.

Nucleolin-based targeting strategies for cancer therapy: from targeted drug delivery to cytotoxic ligands

Cancer is currently the second leading cause of death worldwide and current therapeutic approaches remain ineffective in several cases. Therefore, there is a need to develop more efficacious therapeutic agents, especially for subtypes of cancer lacking targeted therapies. Limited drug penetration into tumors impairs the efficacy of therapies targeting cancer cells. One of the strategies to overcome this problem is targeting the more accessible tumor vasculature via molecules such as nucleolin, which is expressed at the surface of cancer and angiogenic endothelial cells, thus enabling a dual cellular targeting strategy. In this review, we present and discuss nucleolin-based targeting strategies that have been developed for cancer therapy, with a special focus on recent antibody-based approaches.

Polymeric nanoparticles as carrier for targeted and controlled delivery of anticancer agents

In recent decades, many novel methods by using nanoparticles (NPs) have been investigated for diagnosis, drug delivery and treatment of cancer. Accordingly, the potential of NPs as carriers is very significant for the delivery of anticancer drugs, because cancer treatment with NPs has led to the improvement of some of the drug delivery limitations such as low blood circulation time and bioavailability, lack of water solubility, drug adverse effect. In addition, the NPs protect drugs against enzymatic degradation and can lead to the targeted and/or controlled release of the drug. The present review focuses on the potential of NPs that can help the targeted and/or controlled delivery of anticancer agents for cancer therapy.

Enhanced cancer therapy with pH-dependent and aptamer functionalized doxorubicin loaded polymeric (poly D, L-lactic-co-glycolic acid) nanoparticles

Aptamer based drug delivery systems are gaining the importance in anticancer therapy due to their targeted drug delivery efficiency without harming the normal cells. The present work formulated the pH-dependent aptamer functionalized polymer-based drug delivery system against human lung cancer. The prepared aptamer functionalized doxorubicin (DOX) loaded poly (D, L-lactic-co-glycolic acid) (PLGA), poly (N-vinylpyrrolidone) (PVP) nanoparticles (APT-DOX-PLGA-PVP NPs) were spherical in shape with an average size of 87.168 nm. The crystallography and presence of the PLGA (poly (D, L-lactic-co-glycolic acid)) and DOX (doxorubicin) in APT-DOX-PLGA-PVP NPs were indicated by the X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and ¹H and ¹³C nuclear magnetic resonance spectrometer (NMR). The pH-dependent aptamer AS1411 based drug release triggered the cancer cell death was evidenced by cytotoxicity assay, flow cytometry, and fluorescent microscopic imaging. In addition, the cellular uptake of the DOX was determined and the apoptosis-related signaling pathway in the A549 cells was studied by Western blot analysis. Further, the in vivo study revealed that mice treated with APT-DOX-PLGA-PVP NPs were significantly recovered from cancer as evident by mice weight and tumor size followed by the histopathological study. It was reported that the APT-DOX-PLGA-PVP NPs induced the apoptosis through the activation of the apoptosis-related proteins. Hence, the present study revealed that the APT-DOX-PLGA-PVP NPs improved the therapeutic efficiency through the nucleolin receptor endocytosis targeted drug release.

Recent Progress in the Development of Poly(lactic-co-glycolic acid)-Based Nanostructures for Cancer Imaging and Therapy

Diverse nanosystems for use in cancer imaging and therapy have been designed and their clinical applications have been assessed. Among a variety of materials available to fabricate nanosystems, poly(lactic-co-glycolic acid) (PLGA) has been widely used due to its biocompatibility and biodegradability. In order to provide tumor-targeting and diagnostic properties, PLGA or PLGA nanoparticles (NPs) can be modified with other functional materials. Hydrophobic or hydrophilic therapeutic cargos can be placed in the internal space or adsorbed onto the surface of PLGA NPs. Protocols for the fabrication of PLGA-based NPs for cancer imaging and therapy are already well established. Moreover, the biocompatibility and biodegradability of PLGA may elevate its feasibility for clinical application in injection formulations. Size-controlled NP’s properties and ligand–receptor interactions may provide passive and active tumor-targeting abilities, respectively, after intravenous administration. Additionally, the introduction of several imaging modalities to PLGA-based NPs can enable drug delivery guided by in vivo imaging. Versatile platform technology of PLGA-based NPs can be applied to the delivery of small chemicals, peptides, proteins, and nucleic acids for use in cancer therapy. This review describes recent findings and insights into the development of tumor-targeted PLGA-based NPs for use of cancer imaging and therapy.

A DNA aptamer recognizing MMP14 for in vivo and in vitro imaging identified by cell-SELEX

A key challenge for the management of various types of cancer, including pancreatic cancer and hepatocellular carcinoma, is accurate diagnosis at an early stage. Matrix metalloproteinase 14 (MMP14) is overexpressed in numerous types of cancer and is associated with poor prognosis. Therefore, MMP14-specific imaging probes have potential use in the diagnosis of MMP14-positive cancer. Aptamers are short oligonucleotide sequences that can bind to molecular targets with a high specificity and affinity. Aptamers are typically obtained from an in vitro library; this process is usually termed systematic evolution of ligands by exponential enrichment (SELEX). In the present study, a DNA aptamer targeting MMP14 was obtained by cell-SELEX and termed M17, which specifically recognizes MMP14-positive cells. Aptamer M17 selectively binds to membrane proteins of MMP14-transfected 293T cells (Kd, 4.98±1.26 nM). Pancreatic cancer cell imaging suggested that aptamer M17 can bind to the cell membranes of two pancreatic cancer cell lines (MIA PaCa-2 and PANC-1). In vivo tumor imaging demonstrated that the targeting recognition of MIA PaCa-2 tumor cells in mice could be visualized using Cy5-labeled aptamer M17. Aptamer M17-conjugated polyethylene glycol-Fe3O4 can specifically bind to MIA PaCa-2 and PANC-1 cells, and reduce MRI T2-weighted imaging signal intensity. The DNA aptamer M17 has the advantages of simplicity of synthesis, small size, low immunogenicity, high penetrability and high affinity. Therefore, aptamer M17 is a potential molecular probe for the diagnosis and treatment of MMP14-positive cancer.

Viewing the Emphasis on State-of-the-Art Magnetic Nanoparticles: Synthesis, Physical Properties, and Applications in Cancer Theranostics

Cancer-related mortality is a leading cause of death among both men and women around the world. Target-specific therapeutic drugs, early diagnosis, and treatment are crucial to reducing the mortality rate. One of the recent trends in modern medicine is "Theranostics," a combination of therapeutics and diagnosis. Extensive interest in magnetic nanoparticles (MNPs) and ultrasmall superparamagnetic iron oxide nanoparticles (NPs) has been increasing due to their biocompatibility, superparamagnetism, less-toxicity, enhanced programmed cell death, and auto-phagocytosis on cancer cells. MNPs act as a multifunctional, noninvasive, ligand conjugated nano-imaging vehicle in targeted drug delivery and diagnosis. In this review, we primarily discuss the significance of the crystal structure, magnetic properties, and the most common method for synthesis of the smaller sized MNPs and their limitations. Next, the recent applications of MNPs in cancer therapy and theranostics are discussed, with certain preclinical and clinical experiments. The focus is on implementation and understanding of the mechanism of action of MNPs in cancer therapy through passive and active targeting drug delivery (magnetic drug targeting and targeting ligand conjugated MNPs). In addition, the theranostic application of MNPs with a dual and multimodal imaging system for early diagnosis and treatment of various cancer types including breast, cervical, glioblastoma, and lung cancer is reviewed. In the near future, the theranostic potential of MNPs with multimodality imaging techniques may enhance the acuity of personalized medicine in the diagnosis and treatment of individual patients.

The Application of Nucleic Acid Amplification Strategies in Theranostics

Targeting nanoparticles equipped with diagnosis “tools” to malignant cells or tissues for optimal therapy is a popular concept of theranostics. As one of the most reliable and sensitive diagnosis “tools,” nucleic acid detection is of growing practical interest with respect to molecular diagnostics of cancer and other genetic diseases. Particularly, PCR-based and other nucleic acid amplification strategies are most widely used in theranostics. This chapter aims at systematization and critical summarization of the applications of DNA- or RNA-targeted nucleic acid amplification strategies in theranostics.

Stimuli-responsive nanotheranostics intended for oncological diseases: in vitro evaluation of their target, diagnostic and drug release capabilities

This work reports an overview of required in vitro assays to evaluate nanotheranostics applications.

SPIONs embedded in polyamino acid nanogels to synergistically treat tumor microenvironment and breast cancer cells

The extremely complex tumor microenvironment (TME) in humans is the major responsible for the therapeutic failure in cancer nanomedicine. A new concept of disease-driven nanomedicine, henceforth named "Theranomics", which attempts to target cancer cells and TME on the whole, represents an attractive alternative. Herein, a nanomedicine able to co-deliver doxorubicin and a tumor suppressive proteolytic protein such as collagenase-2 was developed. We successfully obtained superparamagnetic nanogels (SPIONs/Doco@Col) via the intermolecular azide-alkyne Huisgen cycloaddition. We demonstrated that a local ECM degradation and remodeling in solid tumors by means of collagenase-2 could enhance tumor penetration of nanomedicines and the in situ sustained release of the drug payload throughout 3-D tumor spheroids up to the core (parenchyma), thus enabling a synergistic and efficient anticancer effect toward highly invasive breast tumors. We illustrate that SPIONs/Doxo@Col is also capable of reducing the invasivity of cancer cells.

Silibinin to improve cancer therapeutic, as an apoptotic inducer, autophagy modulator, cell cycle inhibitor, and microRNAs regulator

Silibinin is a natural plant polyphenol with high antioxidant and anticancer properties, which causes broad-spectrum efficacy against cancer, including cell cycle arrest and apoptosis in most cancer cell types. Silibinin, by modulating the apoptosis, cell cycle progression and autophagic pathways in various cellular and molecular routs might be used to design more effective anticancer strategies. Silibinin also regulates aberrant miRNAs expression linked to many aspects of cell biology in cancer. Maybe the most interesting aspect of silibinin is its ability to trigger multiple cellular signaling pathways to induce a particular biologic effect in various cell types. This review discusses investigations supporting the ability of silibinin to be as a natural modulator of involved cellular biological events in cancer progression. In this review, we introduce the salient features of silibinin therapy to optimize clinical outcomes for oncology patients. The goal of the treatments is to make it possible to eliminate the tumor with the minimum side effects and cure the patient in the early stage cancer. Therefore, plant extracts such as silibinin can be included in the treatments.

Application of aptamers for in vivo molecular imaging and theranostics

Nucleic acid aptamers are small three-dimensional structures of oligonucleotides selected to bind to a target of interest with high affinity and specificity. In vitro, aptamers already compete with antibodies to serve as imaging probes, e.g. for microscopy or flow cytometry. However, they are also increasingly used for in vivo molecular imaging. Accordingly, aptamers have been evaluated over the last twenty years in almost every imaging modality, including single photon emission computed tomography, positron emission tomography, magnetic resonance imaging, fluorescence imaging, echography, and x-ray computed tomography. This review focuses on the studies that were conducted in vivo with aptamer-based imaging probes. It also presents how aptamers have been recently used to develop new types of probes for multimodal imaging and theranostic applications.

A GPC3-specific aptamer-mediated magnetic resonance probe for hepatocellular carcinoma

Purpose

To construct and test a hepatocellular carcinoma (HCC)-targeted magnetic resonance probe based on a glypican-3 (GPC3)-specific aptamer (AP613-1) with ultrasmall superpara-magnetic iron oxide (USPIO).

Methods

Oleic acid-coated USPIO nanoparticles were modified with amino polyethylene glycol on the surface. Amino groups of the USPIO nanoparticles were reacted with the carboxyl group of 5' carboxyl-modified AP613-1, forming an aptamer-mediated USPIO (Apt-USPIO) probe. The material characterization of this probe including transmission electron microscopy (TEM), zeta potential, dynamic laser scattering, and magnetic behavior was carried out. The targeting efficiency and magnetic resonance imaging (MRI) performance of Apt-USPIO were evaluated both in vitro and in vivo with USPIO alone as a control. The cytotoxicity and bio-compatibility of Apt-USPIO and USPIO were analyzed by cell counting kit-8 tests in vitro and animal experiments in vivo.

Results

TEM imaging revealed that the Apt-USPIO nanoparticles were spherical in shape and well dispersed. Specific uptake of Apt-USPIO in Huh-7 cells could be observed using the Prussian blue staining test; however, no uptake of USPIO could be found. In vitro phantom T₂-weighted MRI showed a significant decrease of the signal intensity in Apt-USPIO-incubated Huh-7 cells compared to USPIO-incubated Huh-7 cells. In vivo T₂-weighted MRI showed significantly negative enhancement in the Huh-7 tumors enhanced with Apt-USPIO, whereas no enhancement was found with USPIO alone. Excellent biocompatibility of Apt-USPIO and USPIO was also demonstrated.

Conclusion

In this study, a molecular MRI probe which was highly specific to GPC3 on HCC was successfully prepared. Our results validated the targeted imaging effect of this Apt-USPIO probe in vivo for GPC3-expressing HCCs in xenograft mice.

Targeted cancer drug delivery with aptamer-functionalized polymeric nanoparticles

Based on exceptional advantages of aptamers, increasing attention has been presented in the utilise of them as targeted ligands for cancer drug delivery. Recently, the progress of aptamer-targeted nanoparticles has presented new therapeutic systems for several types of cancer with decreased toxicity and improved efficacy. We highlight some of the promising formulations of aptamer-conjugated polymeric nanoparticles for specific targeted drug delivery to cancer cells. This review paper focuses on the current progresses in the use of the novel strategies to aptamer-targeted drug delivery for chemotherapy. An extensive literature review was performed using internet database, mainly PubMed based on MeSH keywords. The searches included full-text publications written in English without any limitation in date. The abstracts, reviews, books as well as studies without obvious relating of aptamers as targeted ligands for cancer drug delivery were excluded from the study. The reviewed literature revealed that aptamers with ability to modify and conjugate to various molecules can be used as targeted cancer therapy agents. However, development of aptamers unique to each individual's tumour to the development of personalised medicine seems to be needed.

Magnetic polymeric nanoassemblies for magnetic resonance imaging-combined cancer theranostics

Cancer has become one of the primary causes of death worldwide. Current cancer-therapy schemes are progressing relatively slowly in terms of reducing mortality, prolonging survival, time and enhancing cure rate, owing to the enormous obstacles of cancer pathophysiology. Therefore, specific diagnosis and therapy for malignant tumors are becoming more and more crucial and urgent, especially for early cancer diagnosis and cancer-targeted therapy. Derived theranostics that combine several functions into one "package" could further overcome undesirable differences in biodistribution and selectivity between distinct imaging and therapeutic agents. In this article, we discuss a chief clinical diagnosis tool - MRI - focusing on recent progress in magnetic agents or systems in multifunctional polymer nanoassemblies for combing cancer theranostics. We describe abundant polymeric MRI-contrast agents integrated with chemotherapy, gene therapy, thermotherapy, and radiotherapy, as well as other developing directions.

Customizing poly(lactic-co-glycolic acid) particles for biomedical applications

Nano- and microparticles have increasingly widespread applications in nanomedicine, ranging from drug delivery to imaging. Poly(lactic-co-glycolic acid) (PLGA) particles are the most widely-applied type of particles due to their biocompatibility and biodegradability. Here, we discuss the preparation of PLGA particles, and various modifications to tailor particles for applications in biological systems. We highlight new preparation approaches, including microfluidics and PRINT method, and modifications of PLGA particles resulting in novel or responsive properties, such as Janus or upconversion particles. Finally, we describe how the preparation methods can- and should-be adapted to tailor the properties of particles for the desired biomedical application. Our aim is to enable researchers who work with PLGA particles to better appreciate the effects of the selected preparation procedure on the final properties of the particles and its biological implications.

STATEMENT OF SIGNIFICANCE

Nanoparticles are increasingly important in the field of biomedicine. Particles made of polymers are in the spotlight, due to their biodegradability, biocompatibility, versatility. In this review, we aim to discuss the range of formulation techniques, manipulations, and applications of poly(lactic-co-glycolic acid) (PLGA) particles, to enable a researcher to effectively select or design the optimal particles for their application. We describe the various techniques of PLGA particle synthesis and their impact on possible applications. We focus on recent developments in the field of PLGA particles, and new synthesis techniques that have emerged over the past years. Overall, we show how the chemistry of PLGA particles can be adapted to solve pressing biological needs.

Strategies for the enhanced intracellular delivery of nanomaterials

The intracellular delivery of nanomaterials and drugs has been attracting increasing research interest, mainly because of their important effects and functions in several organelles. Targeting specific organelles can help treat or decrease the symptoms of diabetes, cancer, infectious, and autoimmune diseases. Tuning biological and chemical properties enables the creation of functionalized nanomaterials with enhanced intracellular uptake, ability to escape premature lysosome degradation, and to reach a specific target. Here, we provide an update of recent advances in the intracellular delivery mechanisms that could help drugs reach their target more efficiently.

Recent advances on aptamer-based biosensors to detection of platelet-derived growth factor

Platelet-derived growth factor (PDGF-BB), a significant serum cytokine, is an important protein biomarker in diagnosis and recognition of cancer, which straightly rolled in proceeding of various cell transformations, including tumor growth and its development. Fibrosis, atherosclerosis are certain appalling diseases, which PDGF-BB is near to them. Generally, the expression amount of PDGF-BB increases in human life-threatening tumors serving as an indicator for tumor angiogenesis. Thus, identification and quantification of PDGF-BB in biomedical fields are particularly important. Affinity chromatography, immunohistochemical methods and enzyme-linked immunosorbent assay (ELISA), conventional methods for PDGF-BB detection, requiring high-cost and complicated instrumentation, take too much time and offer deficient sensitivity and selectivity, which restrict their usage in real applications. Hence, it is essential to design and build enhanced systems and platforms for the recognition and quantification of protein biomarkers. In the past few years, biosensors especially aptasensors have been received noticeable attention for the detection of PDGF-BB owing to their high sensitivity, selectivity, accuracy, fast response, and low cost. Since the role and importance of developing aptasensors in cancer diagnosis is undeniable. In this review, optical and electrochemical aptasensors, which have been applied by many researchers for PDGF-BB cancer biomarker detection, have been mentioned and merits and demerits of them have been explained and compared. Efforts related to design and development of aptamer-based biosensors using nanoparticles for sensitive and selective detection of PDGF-BB have been reviewed considering: Aptamer importance as recognition elements, principal, application and the recent improvements and developments of aptamer based optical and electrochemical methods. In addition, commercial biosensors and future perspectives for rapid and on-site detection of PDGF-BB have been summarized.

Cancer cell membrane-coated magnetic nanoparticles for MR/NIR fluorescence dual-modal imaging and photodynamic therapy

A photosensitizer-loaded magnetic nanobead with surface coated with a cancer cell membrane to enhance MR/NIR fluorescence imaging and PDT efficacy.

Aptamer: A potential oligonucleotide nanomedicine in the diagnosis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers with a high mortality rate. Late diagnosis and poor prognosis are still a major drawback since curative therapies such as liver resection and liver transplantation are effective only for an early stage HCC. Development of novel molecular targeting therapies against HCC may provide new options that will improve the efficiency of the diagnosis and the success of the therapy, thus ameliorating the life expectancy of the patients. The aptamer is an oligonucleotide nanomedicine that has high binding affinity and specificity to small and large target molecules in the intracellular and extracellular environment with agonist or antagonist function. Currently, several aptamers for diagnostic and therapeutic purposes are under development to recognize different molecules of HCC. In in vitro models, the aptamer has been shown to be able to reduce the growth of HCC cells and increase the sensitivity to conventional chemotherapies. In in vivo mouse models, aptamer could induce cell apoptosis with antitumor activity. Overall data had shown that aptamer has limited toxicity and might be safe in clinical application. This review summarizes recent information of aptamer as a potential oligonucleotide nanomedicine tool, in diagnostics, targeted therapy, and as drug delivery nano-vehicles.

Novel CD123-aptamer-originated targeted drug trains for selectively delivering cytotoxic agent to tumor cells in acute myeloid leukemia theranostics

Since conventional chemotherapy for acute myeloid leukemia (AML) has its limitations, a theranostic platform with targeted and efficient drug transport is in demand. In this study, we developed the first CD123 (AML tumor marker) aptamers and designed a novel CD123-aptamer-mediated targeted drug train (TDT) with effective, economical, biocompatible and high drug-loading capacity. These two CD123 aptamers (termed as ZW25 and CY30, respectively) can bind to a CD123 peptide epitope and CD123 + AML cells with high specificities and KD of 29.41 nM and 15.38 nM, respectively, while has minimal cross reactivities to albumin, IgG and trypsin. Further, TDT is self-assembled from two short primers by ligand-modified ZW25 that acted as initiation position for elongation, while intercalated by doxorubicin (Dox). TDT is capable of transporting high capacity of Dox to CD123 + cells and retains the efficacy of Dox, while significantly reducing drug uptake and eased toxicity to CD123- cells in vitro (p < .01). Moreover, TDT can ease Dox cytoxicity to normal tissues, prolong survivals and inhibit tumor growth of mouse xenograft tumor model in vivo. These suggest that CD123 aptamer and CD123 aptamer-mediated targeted drug delivery system may have potential applications for selective delivery cytotoxic agents to CD123-expressing tumors in AML theranostics.

The Bioactivity of D-/L-Isonucleoside- and 2'-Deoxyinosine-Incorporated Aptamer AS1411s Including DNA Replication/MicroRNA Expression

In this study, chemical modification of 2'-deoxyinosine (2'-dI) and D-/L-isothymidine (D-/L-isoT) was performed on AS1411. They could promote the nucleotide-protein interaction by changing the local conformation. Twenty modified sequences were obtained, FCL-I and FCL-II showed the most noticeable activity improvement. They stabilized the G-quadruplex, remained highly resistant to serum degradation and specificity for nucleolin, further inhibited tumor cell growth, exhibited a stronger ability to influence the different phases of the tumor cell cycle, induced S-phase arrest, promoted the inhibition of DNA replication, and suppressed the unwound function of a large T antigen as powerful as AS1411. The microarray analysis and TaqMan PCR results showed that FCL-II can upregulate the expression of four breast-cancer-related, lowly expressed miRNAs and downregulate the expression of three breast-cancer-related, highly expressed miRNAs (>2.5-fold). FCL-II resulted in enhanced treatment effects greater than AS1411 in animal experiments (p < 0.01). The computational results further proved that FCL-II exhibits more structural advantages than AS1411 for binding to the target protein nucleolin, indicating its great potential in antitumor therapy.

Nano-delivery system targeting to cancer stem cell cluster of differentiation biomarkers

Cancer stem cells (CSCs) are one of the most important origins of cancer progression and metastasis. CSCs have unique self-renewal properties and diverse cell membrane receptors that induced the resistance to the conventional chemotherapeutic agents. Therefore, the therapeutic removal of CSCs could result in the cancer cure with lack of recurrence and metastasis. In this regard, targeting CSCs in accordance to their specific biomarkers is a talented attitude in cancer therapy. Various CSCs surface biomarkers have been described, which some of them exhibited similarities on different cancer cell types, while the others are cancer specific and have just been reported on one or a few types of cancers. In this review, the importance of CSCs in cancer development and therapeutic response has been stated. Different CSCs cluster of differentiation (CD) biomarkers and their specific function and applications in the treatment of cancers have been discussed, Special attention has been made on targeted nano-delivery systems. In this regard, several examples have been illustrated concerning specific natural and artificial ligands against CSCs CD biomarkers that could be decorated on various nanoparticulated drug delivery systems to enhance therapeutic index of chemotherapeutic agents or anticancer gene therapy. The outlook of CSCs biomarkers discovery and therapeutic/diagnostic applications was discussed.

Renal Clearable Peptide Functionalized NaGdF4 Nanodots for High-Efficiency Tracking Orthotopic Colorectal Tumor in Mouse

The effective delivery of bioimaging probes to a selected cancerous tissue has extensive significance for biological studies and clinical investigations. Herein, the peptide functionalized NaGdF₄ nanodots (termed as, pPeptide-NaGdF₄ nanodots) have been prepared for highly efficient magnetic resonance imaging (MRI) of tumor by formation of Gd-phosphonate coordinate bonds among hydrophobic NaGdF₄ nanodots (4.2 nm in diameter) with mixed phosphorylated peptide ligands including a tumor targeting phosphopeptide and a cell penetrating phosphopeptide. The tumor targeting pPeptide-NaGdF₄ nanodots have paramagnetic property with ultrasmall hydrodynamic diameter (HD, c.a., 7.3 nm) which greatly improves their MRI contrast ability of tumor and facilitates renal clearance. In detail, the capability of the pPeptide-NaGdF₄ nanodots as high efficient contrast agent for in vivo MRI is evaluated successfully through tracking small drug induced orthotopic colorectal tumor (c.a., 195 mm³ in volume) in mouse.

Cross-linked enzyme aggregates (CLEAs) and magnetic nanocomposite grafted CLEAs of GH26 endo-β-1,4-mannanase: Improved activity, stability and reusability

A comparative study on immobilization of recombinant endo-β-1,4-mannanase (ManB-1601), using cross-linked aggregated form (MB-C) and novel chitosan magnetic nanocomposites of MB-C (MB-Mag-C) was carried out. FT-IR and Raman spectroscopy were used to confirm the surface modifications while, scanning electron and atomic force microscopy were performed to demonstrate the surface topology and magnetic nature of MB-C and MB-Mag-C. Among MB-C and MB-Mag-C, the former showed better activity and stability in broad range of pH, thermo-stability and kinetic parameters while, the latter showed higher temperature optima and solvent stability. MB-C and MB-Mag-C when compared with free enzyme showed up to 73.2% higher activity (pH 4-9), up to 95.6% higher stability (pH 3-10, 9h incubation at room temperature), up to 15°C higher optimal temperature, higher stability (up to 83%) in the presence of solvents and up to 1.62-fold higher deactivation energy (E_d). Immobilized enzymes were able to repeatedly hydrolyze locust bean gum till 12 cycles and generated predominantly di-, tri- and tetra- species of β-manno-oligosaccharides.