Innovative fluorescent magnetic albumin microbead-assisted cell labeling and intracellular imaging of glioblastoma cells

Application of sulfur-doped graphene quantum dots@gold-carbon nanosphere for electrical pulse-induced impedimetric detection of glioma cells

Glioma is the predominant brain tumor with high death rate. The successful development of biosensor to achieve an efficient detection of glioma cells at low concentration remains a great challenge for the personalized glioma therapy. Herein, an ultrasensitive pulse induced electrochemically impedimetric biosensor for glioma cells detection has been successfully fabricated. The 4-11 nm sulfur-doped graphene quantum dots (S-GQDs) are homogeneously deposited onto gold nanoparticles decorated carbon nanospheres (Au-CNS) by Au-thiol linkage to form S-GQDs@Au-CNS nanocomposite which acts as dual functional probe for enhancing the electrochemical activity as well as conjugating the angiopep-2 (Ang-2) for glioma cell detection. Moreover, the application of an externally electrical pulse at +0.6 V expend the surface of glioma cells to accelerate the attachment of glioma cells onto the Ang-2-conjugated S-GQDs@Au-CNS nanocomposite, resulting in the enhanced sensitivity toward glioma cell detection. An ultrasensitive impedimetric detection of glioma cells with a wide linear range of 100-100,000 cells mL^-1 and a limit of detection of 40 cells mL^-1 is observed. Moreover, the superior selectivity with long-term stability of the developed biosensor in human serum matrix corroborates the feasibility of using S-GQDs@Au-CNS based nanomaterials as the promising sensing probe for practical application to facilitate the ultrasensitive and highly selective detection of cancer cells.

An enzyme-mediated universal fluorescent biosensor template for pathogen detection based on a three-dimensional DNA walker and catalyzed hairpin assembly

An enzyme-mediated universal fluorescent biosensor template for rapid detection of pathogens was developed based on the strategy of a three-dimensional (3D) DNA walker and catalyzed hairpin assembly (CHA) reaction. In the bacterial recognition step, a strand displacement reaction between bacteria and the double-stranded complex caused the release of the walker strand. The walker strand triggered the DNA walker to produce an enzyme fragment, and the DNA walker used gold nanoparticles (AuNPs) as the track to provide an excellent DNA ligand anchoring area. In the CHA step, the enzyme fragment induced the CHA cycle to yield fluorescence signals, which greatly enhanced the conversion ratio of trigger DNA and the sensitivity of the fluorescent biosensor. The effect of the distance and density of the DNA ligand was studied by adjusting the length of poly-adenine (PolyA), and was further explored by its reaction kinetics. By comparing the maximum reaction rate (Vmax), Michaelis constant (Km) and turnover number (Kcat), the optimized PolyA probe was assessed and identified. In this work, the optimized PolyA-DNA probe exhibited an outstanding sensitivity in Salmonella typhimurium (S. ty) detection, which is 11.9 times and 4.6 times higher than those of the SH-DNA and the MCH treated SH-DNA. Meanwhile, a detection limit of 28.1 CFU mL-1 was achieved in Escherichia coli (E. coli) detection. Furthermore, the biosensor achieved good selectivity and high repeatability with recoveries of 91%-115% for real sample detection. Considering these advantages, this template has great potential as a routine tool for pathogen detection and has wide applications in the field of global public health and food safety.

Anti-CD133 Antibody-Targeted Therapeutic Immunomagnetic Albumin Microbeads Loaded with Vincristine-Assisted to Enhance Anti-Glioblastoma Treatment

Poor uptake of antitumor drugs by tumor cells is a critical challenge for anticancer therapeutics. Moreover, the deficiency of specific tumor selectivity for tumor sites may further limit the therapeutic efficacy and cause side effects in healthy regions of the body. Vincristine (VCR) is an effective antitumor drug; however, because of its severe nerve toxicity, short half-life, and fast metabolism, its clinical application is limited. Herein, novel anti-CD133 monoclonal antibody (^CD133mAb)-targeted therapeutic immunomagnetic albumin microbeads (^CD133mAb/TMAMbs) are smartly constructed for enhancing antiglioblastoma treatment. Superparamagnetic iron oxide nanoparticles (SPIO NPs) were first fabricated as nanocarrier cores, then encapsulated with human serum albumin (HSA), and loaded antitumor drug VCR. Then ^CD133mAb, which has specific affinity with the cell membrane CD133, was subsequently conjugated to form ^CD133mAb-decorated therapeutic immunomagnetic albumin microbeads (^CD133mAb/TMAMbs). The influence of ^CD133mAb/TMAMbs on the viability, cell cycle, apoptosis, cell cytoskeleton, migration, and invasion of CD133-overexpressing U251 cells was explored. The ^CD133mAb-conjugated magnetic albumin microbeads exhibited a high drug loading capacity, stability and hemocompatibility, and active targeting ability by specific recognition of the CD133 surface antigen by the bioconjugation of ^CD133mAb. More importantly, the constructed therapeutic ^CD133mAb/TMAMbs have a specifically effective uptake via the CD133 transmembrane protein that is overexpressed in U251 glioblastoma cells and displayed an effective antitumor proliferation and invasive ability. Therefore, based on these results, the fabricated ^CD133mAb/TMAMbs demonstrate promising uses in brain cancer-targeted diagnosis and therapy.

Fluorescent magnetic PEI-PLGA nanoparticles loaded with paclitaxel for concurrent cell imaging, enhanced apoptosis and autophagy in human brain cancer

Magnetic nanoparticles are regarded as a promising drug delivery vehicle with the improved efficacy and lowered side effects for antitumor therapy. Herein, the poly lactic-co-glycolic acid (PLGA) modified magnetic nanoplatform was synthesized using superparamagnetic γ-Fe₂O₃ nanoparticles (MNPs) as a core, and then labelled with polyethylenimine (PEI)-conjugated fluorescein isothiocyanate (FITC), and simultaneously loaded with antitumor drug paclitaxel (PTX) for theranostic analysis of antitumor effects investigated in human brain glioblastoma U251 cells. As a result, the prepared PEI-PLGA-MNPs showed a relatively round sphere with an average size of 80 nm approximately, and the FITC-labeling PEI-PLGA-MNPs were efficiently endocytosed by the U251 cells for cellular imaging. Moreover, the fabricated PEI-PLGA-PTX-MNPs also demonstrated an inhibition of the targeted cell proliferation and migration, and a programmed cell death, via both apoptosis modulating by a burst of reactive oxygen species (ROS) and autophagy with accumulation of autophagosomes and LC3-II signals detected in the treated glioblastoma U251 cells after uptaking. Therefore, the constructed nanoplatform could be effectively applied for simultaneous cellular imaging and drug delivery in human brain glioblastoma treatment in future.

Synthesis of tumor-targeted folate conjugated fluorescent magnetic albumin nanoparticles for enhanced intracellular dual-modal imaging into human brain tumor cells

Superparamagnetic iron oxide nanoparticles (SPIO NPs), utilized as carriers are attractive materials widely applied in biomedical fields, but target-specific SPIO NPs with lower toxicity and excellent biocompatibility are still lacking for intracellular visualization in human brain tumor diagnosis and therapy. Herein, bovine serum albumin (BSA) coated superparamagnetic iron oxide, i.e. γ-Fe2O3 nanoparticles (BSA-SPIO NPs), are synthesized. Tumor-specific ligand folic acid (FA) is then conjugated onto BSA-SPIO NPs to fabricate tumor-targeted NPs, FA-BSA-SPIO NPs as a contrast agent for MRI imaging. The FA-BSA-SPIO NPs are also labeled with fluorescein isothiocyanate (FITC) for intracellular visualization after cellular uptake and internalization by glioma U251 cells. The biological effects of the FA-BSA-SPIO NPs are investigated in human brain tumor U251 cells in detail. These results show that the prepared FA-BSA-SPIO NPs display undetectable cytotoxicity, excellent biocompatibility, and potent cellular uptake. Moreover, the study shows that the made FA-BSA-SPIO NPs are effectively internalized for MRI imaging and intracellular visualization after FITC labeling in the targeted U251 cells. Therefore, the present study demonstrates that the fabricated FITC-FA-BSA-SPIO NPs hold promising perspectives by providing a dual-modal imaging as non-toxic and target-specific vehicles in human brain tumor treatment in future.

Transferrin-conjugated drug/dye-co-encapsulated magnetic nanocarriers for active-targeting fluorescent/magnetic resonance imaging and anti-tumor effects in human brain tumor cells

A combinatorial nanosystem with the advantages of superparamagnetic iron oxide nanoparticles (SPIO NPs) and targeting polymer carriers is expected to improve the therapeutic effects in developing multifunctional delivery systems.

Poly (caprolactone) microparticles and chitosan thermogels based injectable formulation of etoricoxib for the potential treatment of osteoarthritis

This study aimed to evaluate Poly (caprolactone) microparticles (MPs) loaded composite injectable Chitosan gel (CICGs) as a dual purpose (visco-supplement and intra articular drug delivery depot) therapeutic agent for the treatment of Osteoarthritis. Etoricoxib (COX-2 inhibitor), a highly hydrophobic drug was chosen as a model drug for the study. When administered orally, Etoricoxib poses severe cardiovascular toxicity issues. So, we have attempted to deliver this drug intra-articularly, which could retain the drug longer in the joint region and thus could ameliorate these toxicity issues. CICGs were prepared by dispersing MPs in the chitosan-Ammonium hydrogen phosphate solution and incubated at 37 °C. Rheology studies proved that gels were stable and had visco-elastic properties comparable to that of existing visco-supplements. The in vitro drug release profiles of CICGs were found to be more controlled when compared to MPs and bare chitosan gel (BCGs). In vitro and in vivo biocompatibility studies proved that the gels were biocompatible. In vivo synovial drug clearance studies proved that CICGs had a better drug retention capacity than BCGs and MPs. In vivo fluorescence imaging results confirmed that CICGs could stay longer in the joint region when compared to BCGs and MPs. Thus this novel CICGs could be a potential dual purpose gel for the treatment of diseased joint regions especially for Osteoarthritis.

Polyethylenimine mediated magnetic nanoparticles for combined intracellular imaging, siRNA delivery and anti-tumor therapy

PEI–magnetic γ-Fe₂O₃nanoparticles (MNPs) were modified with fluorescent FITC for intracellular imaging and were also used for survivin siRNA delivery. The results suggested that the fabricated PEI–MNPs are a promising nanovehicle for efficient anti-tumor therapy.

Highly Efficient Labeling of Human Lung Cancer Cells Using Cationic Poly-l-lysine-Assisted Magnetic Iron Oxide Nanoparticles

Cell labeling with magnetic iron oxide nanoparticles (IONPs) is increasingly a routine approach in the cell-based cancer treatment. However, cell labeling with magnetic IONPs and their leading effects on the biological properties of human lung carcinoma cells remain scarcely reported. Therefore, in the present study the magnetic γ-Fe₂O₃ nanoparticles (MNPs) were firstly synthesized and surface-modified with cationic poly-l-lysine (PLL) to construct the PLL-MNPs, which were then used to magnetically label human A549 lung cancer cells. Cell viability and proliferation were evaluated with propidium iodide/fluorescein diacetate double staining and standard 3-(4,5-dimethylthiazol-2-diphenyl-tetrazolium) bromide assay, and the cytoskeleton was immunocytochemically stained. The cell cycle of the PLL-MNP-labeled A549 lung cancer cells was analyzed using flow cytometry. Apoptotic cells were fluorescently analyzed with nuclear-specific staining after the PLL-MNP labeling. The results showed that the constructed PLL-MNPs efficiently magnetically labeled A549 lung cancer cells and that, at low concentrations, labeling did not affect cellular viability, proliferation capability, cell cycle, and apoptosis. Furthermore, the cytoskeleton in the treated cells was detected intact in comparison with the untreated counterparts. However, the results also showed that at high concentration (400 µg mL^-1), the PLL-MNPs would slightly impair cell viability, proliferation, cell cycle, and apoptosis and disrupt the cytoskeleton in the treated A549 lung cancer cells. Therefore, the present results indicated that the PLL-MNPs at adequate concentrations can be efficiently used for labeling A549 lung cancer cells and could be considered as a feasible approach for magnetic targeted anti-cancer drug/gene delivery, targeted diagnosis, and therapy in lung cancer treatment.