Highly versatile SPION encapsulated PLGA nanoparticles as photothermal ablators of cancer cells and as multimodal imaging agents

We have designed versatile polymeric nanoparticles with cancer cell specific targeting capabilities via aptamer conjugation after the successful encapsulation of curcumin and superparamagnetic iron oxide nanoparticles (SPIONs) inside a PLGA nanocapsule. These targeted nanocomposites were selectively taken up by tumor cells, under in vitro conditions, demonstrating the effectiveness of the aptamer targeting mechanism. Moreover, the nanocomposite potentially functioned as efficient multiprobes for optical, magnetic resonance imaging (MRI) and photoacoustic imaging contrast agents in the field of cancer diagnostics. The hyperthermic ability of these nanocomposites was mediated by SPIONs upon NIR-laser irradiation. In vitro cytotoxicity was shown by curcumin-loaded nanoparticles as well as the photothermal ablation of cancer cells mediated by the drug-encapsulated nanocomposite demonstrated the potential therapeutic effect of the nanocomposite. In short, we portray the aptamer-conjugated nanocomposite as a multimodal material capable of serving as a contrast agent for MR, photoacoustic and optical imaging. Furthermore, the nanocomposite functions as a targetable drug nanocarrier and a NIR-laser inducible hyperthermic material that is capable of ablating PANC-1 and MIA PaCa-2 cancer cell lines.

Formation of Core-Shell Nanoparticles Composed of Magnetite and Samarium Oxide in Magnetospirillum magneticum Strain RSS-1

Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe₃O₄) or greigite (Fe₃S₄) particles in the cells. Recently, several studies have shown some possibilities of controlling the biomineralization process and altering the magnetic properties of magnetosomes by adding some transition metals to the culture media under various environmental conditions. Here, we successfully grow Magnetospirillum magneticum strain RSS-1, which are isolated from a freshwater environment, and find that synthesis of magnetosomes are encouraged in RSS-1 in the presence of samarium and that each core magnetic crystal composed of magnetite is covered with a thin layer of samarium oxide (Sm₂O₃). The present results show some possibilities of magnetic recovery of transition metals and synthesis of some novel structures composed of magnetic particles and transition metals utilizing MTB.

Synthesis of magnetic alloy-filling carbon nanoparticles in super-critical benzene irradiated with an ultraviolet laser

Magnetic nanoparticles are of great importance particularly in the field of biomedicine as well as nanotechnology and nano materials science and technology. Here, we synthesise magnetic alloy-filling carbon nanoparticles (MA@C NPs) via the following two-step procedure; (1) Irradiation of a laser beam of 266 nm wavelength into super-critical benzene, in which both ferrocene and cobaltocene are dissolved, at 290 °C; and (2) annealing of the particles at 600 and 800 °C. We find that the core particles are composed of cobalt (Co), iron (Fe) and oxygen (O) and covered with carbon layers. The structure of the core particles as-synthesised, and annealed at 600 and 800 °C, is, respectively, amorphous, CoFe₂O₄ and FeCo. We also investigate the viability of L929 cells in the presence of MA@C NPs and find that there is no serious advert effect of the MA@C NPs on the cell viability thanks to the carbon layers covering the core particles. The magnetic properties are well characterised. The saturation and remnant magnetisation and coercivity increase and as a result, the hyperthermic efficiency becomes higher with an increase in the annealing temperature. The further modification of the surface of the present particles with several functional molecules becomes easier due to the carbon layers, which makes the present particles more valuable. It is therefore supposed that the presently synthesised MA@C NPs may well be utilised for nanotechnology-based biomedical engineering; e.g., nano bioimaging, nano hyperthermia and nano surgery.

Dual mode of cancer cell destruction for pancreatic cancer therapy using Hsp90 inhibitor loaded polymeric nano magnetic formulation

Heat Shock Protein 90 (Hsp90) has been extensively explored as a potential drug target for cancer therapies. 17- N-allylamino- 17-demethoxygeldanamycin (17AAG) was the first Hsp90 inhibitor to enter clinical trials for cancer therapy. However, native drug is being shown to have considerable anticancer efficacy against pancreatic cancer when used in combination therapy regime. Further, magnetic hyperthermia has shown to have promising effects against pancreatic cancer in combination with known cyto-toxic drugs under both target and non-targeted scenarios. Hence, in order to enhance the efficacy of 17AAG against pancreatic cancer, we developed poly (lactic-co-glycolic acid) (PLGA) coated, 17AAG and Fe3O4 loaded magnetic nanoparticle formulations by varying the relative concentration of polymer. We found that polymer concentration affects the magnetic strength and physicochemical properties of formulation. We were also able to see that our aqueous dispensable formulations were able to provide anti-pancreatic cancer activity for MIA PaCa-2 cell line in dose and time dependent manner in comparison to mice fibroblast cell lines (L929). Moreover, the in-vitro magnetic hyperthermia against MIA PaCa-2 provided proof principle that our 2-in-1 particles may work against cancer cell lines effectively.

Composition, Electronic and Magnetic Investigation of the Encapsulated ZnFe2O 4 Nanoparticles in Multiwall Carbon Nanotubes Containing Ni Residuals

We report investigation on properties of multiwall carbon nanotubes (mCNTs) containing Ni residuals before and after encapsulation of zinc ferrite nanoparticles. The pristine tubes exhibit metallic character with a 0.3 eV reduction in the work function along with ferromagnetic behavior which is attributed to the Ni residuals incorporated during the preparation of tubes. Upon encapsulation of zinc ferrite nanoparticles, 0.5 eV shift in Fermi level position and a reduction in both the π band density of state along with a change in the hybridized sp(2)/sp(3) ratio of the tubes from 2.04 to 1.39 are observed. As a result of the encapsulation, enhancement in the σ bands density of state and coating of the zinc ferrite nanoparticles by the internal layers of the CNTs in the direction along the tube axis is observed. Furthermore, Ni impurities inside the tubes are attracted to the encapsulated zinc ferrite nanoparticles, suggesting the possibility of using these particles as purifying agents for CNTs upon being synthesized using magnetic catalyst particles. Charge transfer from Ni/mCNTs to the ZnFe2O4 nanoparticles is evident via reduction of the density of states near the Fermi level and a 0.3 eV shift in the binding energy of C 1 s core level ionization. Furthermore, it is demonstrated that encapsulated zinc ferrite nanoparticles in mCNTs resulted in two interacting sub-systems featured by distinct blocking temperatures and enhanced magnetic properties; i.e., large coercivity of 501 Oe and saturation magnetization of 2.5 emu/g at 4 K.

FITC/suramin harboring silica nanoformulations for cellular and embryonic imaging/anti-angiogenic theranostics

The in vitro and in vivo uptake, toxicological analysis and anti-angiogenic theranostic prospect of FITC loaded (FITC-Si) and suramin loaded (Sur-Si) silica nanoparticles are presented. FITC/suramin encapsulated silica nanoparticles (NPs) with an average size of <30 nm were synthesized. The uptake of FITC-Si by human umbilical vein endothelial cells (HuVECs) (in vitro) and by early stage medaka embryos (in vivo) was monitored by fluorescence microscopy. The nanoformulation was found to be biocompatible with both cells and embryos. The cytotoxicity analysis, tubulogenesis and migration assay confirmed the anti-angiogenic potential of Sur-Si NPs in HuVECs. The imaging of medaka embryos exposed to FITC-Si, their survival and hatching rate and biocompatibility post FITC-Si exposure were documented. The in vivo drug delivery mediated anti-angiogenic potential of Sur-Si NPs was assessed by survival and hatching rate analysis along with morphological indicators. At higher concentrations, Sur-Si proved lethal to embryos, whereas at lower concentrations it was rather an efficient anti-angiogenic formulation leading to malformed vasculogenesis and inhibited intersegmental vessel formation in an efficient dose dependent mode. The results indicate the potential application of such nanoformulation in future anti-angiogenic theranostics.

Effect of Polyethylene Glycol on the Formation of Magnetic Nanoparticles Synthesized by Magnetospirillum magnetotacticum MS-1

Magnetotactic bacteria (MTB) synthesize intracellular magnetic nanocrystals called magnetosomes, which are composed of either magnetite (Fe3O4) or greigite (Fe3S4) and covered with lipid membranes. The production of magnetosomes is achieved by the biomineralization process with strict control over the formation of magnetosome membrane vesicles, uptake and transport of iron ions, and synthesis of mature crystals. These magnetosomes have high potential for both biotechnological and nanotechnological applications, but it is still extremely difficult to grow MTB and produce a large amount of magnetosomes under the conventional cultural conditions. Here, we investigate as a first attempt the effect of polyethylene glycol (PEG) added to the culture medium on the increase in the yield of magnetosomes formed in Magnetospirillum magnetotacticum MS-1. We find that the yield of the formation of magnetosomes can be increased up to approximately 130 % by adding PEG200 to the culture medium. We also measure the magnetization of the magnetosomes and find that the magnetosomes possess soft ferromagnetic characteristics and the saturation mass magnetization is increased by 7 %.

Multi-stimuli responsive Cu2S nanocrystals as trimodal imaging and synergistic chemo-photothermal therapy agents

A size and shape tuned, multifunctional metal chalcogenide, Cu2S-based nanotheranostic agent is developed for trimodal imaging and multimodal therapeutics against brain cancer cells. This theranostic agent was highly efficient in optical, photoacoustic and X-ray contrast imaging systems. The folate targeted NIR-responsive photothermal ablation in synergism with the chemotherapeutic action of doxorubicin proved to be a rapid precision guided cancer-killing module. The multi-stimuli, i.e., pH-, thermo- and photo-responsive drug release behavior of the nanoconjugates opens up a wider corridor for on-demand triggered drug administration. The simple synthesis protocol, combined with the multitudes of interesting features packed into a single nanoformulation, clearly demonstrates the competing role of this Cu2S nanosystem in future cancer treatment strategies.

An ‘all in one’ approach for simultaneous chemotherapeutic, photothermal and magnetic hyperthermia mediated by hybrid magnetic nanoparticles

Trimodal (chemo-photothermal and MHT) lethality imparted by triple targeted dual drug loaded hybrid MNPs.

Mevalonates restore zoledronic acid-induced osteoclastogenesis inhibition

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is likely to be caused by continuous imperfection of bone healing after surgical treatments in patients with long-term administration of nitrogen-containing bisphosphonates (NBPs). NBPs inhibit osteoclastic bone resorption by impairing the mevalonic acid sterol pathway in osteoclasts. Thus, we hypothesized that exogenous mevalonic acid metabolites restore the inhibitory effects of NBPs on osteoclastogenesis and bone remodeling. To clarify the effects of mevalonic acid metabolites, especially geranylgeranyl pyrophosphate (GGPP) and geranylgeranyl transferase substrate geranylgeranyl acid (GGOH), we examined the effects of zoledronic acid with or without GGOH or GGPP on osteoclast differentiation, multinucleation, and bone mineral deposition in tooth-extracted sockets. Zoledronic acid decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells derived from mouse osteoclast precursors treated with receptor activator of nuclear factor-κB ligand and macrophage colony-stimulating factor. Zoledronic acid simultaneously suppressed not only the expressions of osteoclastic differentiation-related molecules such as TRAP, cathepsin K, calcitonin receptor, and vacuolar H-ATPase but also those of multinucleation-related molecules such as dendrocyte-expressed 7 transmembrane proteins and osteoclast stimulatory transmembrane protein. Treatment with GGOH or GGPP, but not farnesyl acid, restored the zoledronic acid-inhibited number of TRAP-positive multinuclear cells together with the expressions of these molecules. Although intraperitoneal administration of zoledronic acid and lipopolysaccharide into mice appeared to induce BRONJ-like lesions with empty bone lacunae and decreased mineral deposition in tooth-extracted socket, both GGOH and GGPP partially restored the inhibitory effects on zoledronic acid-related mineral deposition. These results suggest the potential of mevalonic acid metabolites as therapeutic agents for BRONJ.

Quantum dot tailored to single wall carbon nanotubes: a multifunctional hybrid nanoconstruct for cellular imaging and targeted photothermal therapy

Hybrid nanomaterial based on quantum dots and SWCNTs is used for cellular imaging and photothermal therapy. Furthermore, the ligand conjugated hybrid system (FaQd@CNT) enables selective targeting in cancer cells. The imaging capability of quantum dots and the therapeutic potential of SWCNT are available in a single system with cancer targeting property. Heat generated by the system is found to be high enough to destroy cancer cells.

Curcumin and 5-fluorouracil-loaded, folate- and transferrin-decorated polymeric magnetic nanoformulation: a synergistic cancer therapeutic approach, accelerated by magnetic hyperthermia

The efficient targeting and therapeutic efficacy of a combination of drugs (curcumin and 5-Fluorouracil [5FU]) and magnetic nanoparticles encapsulated poly(D,L-lactic-co-glycolic acid) nanoparticles, functionalized with two cancer-specific ligands are discussed in our work. This multifunctional, highly specific nanoconjugate resulted in the superior uptake of nanoparticles by cancer cells. Upon magnetic hyperthermia, we could harness the advantages of incorporating magnetic nanoparticles that synergistically acted with the drugs to destroy cancer cells within a very short period of time. The remarkable multimodal efficacy attained by this therapeutic nanoformulation offers the potential for targeting, imaging, and treatment of cancer within a short period of time (120 minutes) by initiating early and late apoptosis.

Fluorinated graphene oxide; a new multimodal material for biological applications

Fluorinated graphene oxide (FGO) is reported for the first time as a magnetically responsive drug carrier that can serve both as a magnetic resonance imaging (MRI) and photoacoustic contrast agent, under preclinical settings, and as a type of photothermal therapy. Its hydrophilic nature facilitates biocompatibility. FGO as a broad wavelength absorber, with high charge transfer and strong non-linear scattering is optimal for NIR laser-induced hyperthermia.

Accelerated killing of cancer cells using a multifunctional single-walled carbon nanotube-based system for targeted drug delivery in combination with photothermal therapy

The photothermal effect of single-walled carbon nanotubes (SWCNTs) in combination with the anticancer drug doxorubicin (DOX) for targeting and accelerated destruction of breast cancer cells is demonstrated in this paper. A targeted drug-delivery system was developed for selective killing of breast cancer cells with polyethylene glycol biofunctionalized and DOX-loaded SWCNTs conjugated with folic acid. In our work, in vitro drug-release studies showed that the drug (DOX) binds at physiological pH (pH 7.4) and is released only at a lower pH, ie, lysosomal pH (pH 4.0), which is the characteristic pH of the tumor environment. A sustained release of DOX from the SWCNTs was observed for a period of 3 days. SWCNTs have strong optical absorbance in the near-infrared (NIR) region. In this special spectral window, biological systems are highly transparent. Our study reports that under laser irradiation at 800 nm, SWCNTs exhibited strong light–heat transfer characteristics. These optical properties of SWCNTs open the way for selective photothermal ablation in cancer therapy. It was also observed that internalization and uptake of folate-conjugated NTs into cancer cells was achieved by a receptor-mediated endocytosis mechanism. Results of the in vitro experiments show that laser was effective in destroying the cancer cells, while sparing the normal cells. When the above laser effect was combined with DOX-conjugated SWCNTs, we found enhanced and accelerated killing of breast cancer cells. Thus, this nanodrug-delivery system, consisting of laser, drug, and SWCNTs, looks to be a promising selective modality with high treatment efficacy and low side effects for cancer therapy.

Activity of lipase and chitinase immobilized on superparamagnetic particles in a rotational magnetic field

We immobilize hydrolases such as lipase and chitinase on superparamagnetic particles, which are subjected to a rotational magnetic field, and measure the activities of the enzymes. We find that the activities of lipase and chitinase increase in the rotational magnetic field compared to those in the absence of a magnetic field and reach maximum at certain frequencies. The present methodology may well be utilized for the design and development of efficient micro reactors and micro total analysis systems (μ-TASs).

Multifunctional carboxymethyl cellulose-based magnetic nanovector as a theragnostic system for folate receptor targeted chemotherapy, imaging, and hyperthermia against cancer

A multifunctional biocompatible nanovector based on magnetic nanoparticle and carboxymethyl cellulose (CMC) was developed. The nanoparticles have been characterized using TEM, SEM, DLS, FT-IR spectra, VSM, and TGA studies. We found that the synthesized carboxymethyl cellulose magnetic nanoparticles (CMC MNPs) were spherical in shape with an average size of 150 nm having low aggregation and superparamagnetic properties. We found that the folate-tagged CMC MNPs were delivered to cancer cells by a folate-receptor-mediated endocytosis mechanism. 5-FU was encapsulated as a model drug for delivering cytotoxicity, and we could demonstrate the sustained release of 5-FU. It was also observed that the FITC-labeled CMC MNPs could effectively enter cells, and the fate of nanoparticles was tracked with Lysotracker. The CMC MNPs could induce significant cell death when an alternating magnetic field was applied. These results indicate that the multifunctional CMC MNPs possess a high drug loading efficiency and high biocompatibility and with low cell cytotoxicity and can be considered to be promising candidates for CMC-based targeted drug delivery, cellular imaging, and magnetic hyperthermia (MHT).

Synergistic targeting of cancer and associated angiogenesis using triple-targeted dual-drug silica nanoformulations for theragnostics

The targeting and therapeutic efficacy of dye- and dual-drug-loaded silica nanoparticles, functionalized with triple targeting ligands specific towards cancer and neoangiogenesis simultaneously, are discussed. This synergized, high-precision, multitarget concept culminates in an elevated uptake of nanoparticles by cancer and angiogenic cells with amplified proficiency, thereby imparting superior therapeutic efficacy against breast cancer cells and completely disabling the migration and angiogenic sprouting ability of activated endothelial cells. The exceptional multimodal efficiency achieved by this single therapeutic nanoformulation holds promise for the synergistic targeting and treatment of the yet elusive cancer and its related angiogenesis in a single, lethal shot.

Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging

This paper presents the synthesis of aqueous cadmium sulfide (CdS) quantum dots (QDs) and silica-encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio-optical probes. We report the role of CdS as an efficient cell tag with fluorescence on par with previously documented cadmium telluride and cadmium selenide QDs, which have been considered to impart high levels of toxicity. In this study, the toxicity of bare QDs was efficiently quenched by encapsulating them in a biocompatible coat of silica. The toxicity profile and uptake of bare CdS QDs and silica-coated QDs, along with the CD31-labeled, silica-coated CdS QDs on human umbilical vein endothelial cells and glioma cells, were investigated. The effect of size, along with the time-dependent cellular uptake of the nanomaterials, has also been emphasized. Enhanced, high-specificity imaging toward endothelial cell lines in comparison with glioma cells was achieved with CD31 antibody-conjugated nanoparticles. The silica-coated nanomaterials exhibited excellent biocompatibility and greater photostability inside live cells, in addition to possessing an extended shelf life. In vivo biocompatibility and localization study of silica-coated CdS QDs in medaka fish embryos, following direct nanoparticle exposure for 24 hours, authenticated the nanomaterials’ high potential for in vivo imaging, augmented with superior biocompatibility. As expected, CdS QD-treated embryos showed 100% mortality, whereas the silica-coated QD-treated embryos stayed viable and healthy throughout and after the experiments, devoid of any deformities. We provide highly cogent and convincing evidence for such silica-coated QDs as a model nanoparticle in practice, to achieve in vitro and in vivo precision targeted imaging.

AS1411 aptamer tagged PLGA-lecithin-PEG nanoparticles for tumor cell targeting and drug delivery

Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug-loaded PLGA-lecithin-PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The drug-loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF-7 and GI-1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110 nm. Drug-loading studies indicated that under the same drug loading, the aptamer-targeted NPs show enhanced cancer killing effect compared to the corresponding non-targeted NPs. In addition, the PLGA-lecithin-PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer-PLGA-lecithin-PEG NPs are potential carrier candidates for differential targeted drug delivery.

Biomimetic smart nanocomposite: in vitro biological evaluation of zein electrospun fluorescent nanofiber encapsulated CdS quantum dots

New hybrid quantum dot (QD)/nanofibers have potential applications in a variety of fields. A novel fluorescent nanocomposite nanofiber material, consisting of CdS and zein has been fabricated through the electrospinning process. A detailed optimization was carried out to fabricate continuous and uniform nanofibers without beads or droplets. The synthesized hybrid nanofibers were characterized by various state-of-the-art techniques such as scanning electron microscopy, transmission electron microscopy (TEM), TEM-energy dispersive spectrometry, atomic force microscopy and confocal fluorescence micrography. The optimization process was carried out to fabricate fibers ranging from 200 to 450 nm in diameter. The electrical conductivity of the zein-CdS hybrid nanofiber substrates was tested. The potential use of the electrospun CdS-encapsulated nanofibrous scaffold as substrates for cell/tissue culture was evaluated with two different cell types, i.e. mesenchymal stem cells and fibroblasts. The results showed that the electrospun fibrous scaffolds could support the attachment and the proliferation of cells. In addition, the cells cultured on the fibrous scaffolds exhibited normal cell shapes and integrated well with surrounding fibers. The obtained results confirmed the potential for the use of the electrospun QD-encapsulated fluorescent nanofiber mats as scaffolds for tissue engineering.

Aptamer-labeled PLGA nanoparticles for targeting cancer cells

Cancer is one of the leading causes of death in most parts of the world and is a very serious cause of concern particularly in developing countries. In this work, we prepared and evaluated the aptamer-labeled paclitaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Apt-PTX-PLGA NPs) which can ameliorate drug bioavailability and enable accurate drug targeting to cancer cells with controlled drug release for cancer therapy. Paclitaxel-loaded PLGA nanoparticles (PTX-PLGA NPs) were formulated by a single-emulsion/solvent evaporation method and were further surface-functionalized with a chemical cross-linker bis(sulfosuccinimidyl) suberate (BS3) to enable binding of aptamer on to the surface of the nanoparticles. The prepared nanoparticles were characterized by atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Cytotoxicity studies were carried out using normal human mammary epithelial cells (HMEC cells) and human glial cancer cells (GI-1 cells) by methylthiazolyldiphenyl-tetrazolium bromide assay and Alamar blue assay, which confirmed that PTX-PLGA NPs with aptamer conjugation (Apt-PTX-PLGA NPs) were comparatively non-toxic to HMEC cells while toxic to GI-1 cancer cells. Cellular uptake of PTX-PLGA NPs with and without aptamer conjugation was studied using GI-1 cells and monitored by confocal microscopy and phase contrast microscopy. Our studies demonstrated significant internalization and retention of nanoparticles inside the cells, inducing apoptosis. The preferential accumulation of PTX-PLGA NPs within the cancer cells were also confirmed by flow cytometry-based uptake studies. The results indicated that Apt-PTX-PLGA NPs could be a promising targeted therapeutic delivery vehicle for cancer treatment.

PEG coated biocompatible cadmium chalcogenide quantum dots for targeted imaging of cancer cells

Cancer stands as a leading cause of mortality worldwide and diagnostics of cancer still faces drawbacks. Optical imaging of cancer would allow early diagnosis, evaluation of disease progression and therapy efficiency. To that aim, we have developed highly biocompatible PEG functionalized cadmium chalcogenide based three differently luminescent quantum dots (QDs) (CdS, CdSe and CdTe). Folate targeting scheme was utilized for targeting cancer cell line, MCF-7. We demonstrate the biocompatibility, specificity and efficiency of our nanotool in detection of cancer cells sparing normal cell lines with retained fluorescence of functionalized QDs as parental counterpart. This is the first time report of utilizing three differently fluorescent QDs and we have detailed about the internalization of these materials and time dependent saturation of targeting schemes. We present here the success of utilizing our biocompatible imaging tool for early diagnosis of cancer.

Ordered complex structures formed by paramagnetic particles via self-assembly under an ac/dc combined magnetic field

We apply ac and dc magnetic fields simultaneously in orthogonal directions to each other to a solution, in which paramagnetic microparticles are dispersed, and show that complex secondary structures composed of oscillating chain clusters, that is, long linear clusters interconnected by T-, L-, and criss-cross-junctions, are self-assembled. Disklike clusters are formed at some junctions and the number of disklike clusters increases as the frequency of the ac magnetic field increases. We finally show that the angle between long linear clusters can be altered by changing the ratio of the intensities of the ac and dc magnetic fields.

Aptamer conjugated magnetic nanoparticles as nanosurgeons

Magnetic nanoparticles have shown promise in the fields of targeted drug delivery, hyperthermia and magnetic resonance imaging (MRI) in cancer therapy. The ability of magnetic nanoparticles to undergo surface modification and the effect of external magnetic field in the dynamics of their movement make them an excellent nanoplatform for cancer destruction. Surgical removal of cancerous or unwanted cells selectively from the interior of an organ or tissue without any collateral damage is a serious problem due to the highly infiltrative nature of cancer. To address this problem in surgery, we have developed a nanosurgeon for the selective removal of target cells using aptamer conjugated magnetic nanoparticles controlled by an externally applied three-dimensional rotational magnetic field. With the help of the nanosurgeon, we were able to perform surgical actions on target cells in in vitro studies. LDH and intracellular calcium release assay confirmed the death of cancer cells due to the action of the nanosurgeon which in turn nullifies the possibility of proliferation by the removed cells. The nanosurgeon will be a useful tool in the medical field for selective surgery and cell manipulation studies. Additionally, this system could be upgraded for the selective removal of complex cancers from diverse tissues by incorporating various target specific ligands on magnetic nanoparticles.

Thalidomide prevents formation of multinucleated giant cells (Langhans-type cells) from cultured monocytes: possible pharmaceutical applications for granulomatous disorders

Thalidomide is an effective drug for chronic inflammatory diseases, but the mechanism underlying its immunomodulatory action remains uncertain. Thalidomide has been reported to clinically improve chronic inflammatory granulomatous disorders. In such disorders, the granulomas consist of epithelioid cells, scattered lymphocytes and multinucleated giant cells (MNGC; Langhans-type cells). The present experimental approach permitted the reproduction of MNGC formation from peripheral blood monocytes and examination of thalidomides effect on it. MNGC can be effectively generated from monocytes cultured in the presence of interleukin-4 (IL-4) and macrophage colony-stimulating factor(M-CSF) for 14 days. Thalidomide can inhibit the formation of MNGC in a dose-dependent manner. MNGC formation was partly inhibited by the presence of neutralizing TNF-alpha antibody in the responses induced by IL-4 and M-CSF. Autocrinal TNF-alpha production and modulation of cadhelin expression to regulate cell adhesion might be involved in this inhibitory action of thalidomide. Our results support thalidomides clinical efficacy in the treatment of chronic granulomatous disorders (granulomatosis).

Tumbling motion of magnetic particles on a magnetic substrate induced by a rotational magnetic field

We analyze the dynamics of paramagnetic particles on a paramagnetic substrate under a rotational magnetic field. When the paramagnetic particles are subjected to a rotational magnetic field, the rotational plane of which is perpendicular to the substrate surface, the particles form chain clusters caused by the dipole-dipole interaction between the particles and these clusters display a tumbling motion under certain conditions. In this case, the angular momentum of the clusters is converted to a translational one through the force of friction acting between the particles and substrate and, as a result, the clusters move along the surface of the substrate. We analyze the conditions under which the tumbling motion occurs and the dependence of the translational velocity of a cluster on the control parameters by the Stokesian dynamics method. Based on the dynamics of magnetic particles, we propose a method of manipulating nano- and microparticles using a rotational magnetic field. We demonstrate the manipulation of magnetic and nonmagnetic particles, a carbon nanotube, and a biological cell.

Synthesis and cancer antiproliferative activity of new histone deacetylase inhibitors: hydrophilic hydroxamates and 2-aminobenzamide-containing derivatives

New series histone deacetylase inhibitors comprising a hydroxamic acid or 2-aminobenzamide group as a zinc-chelating function were synthesized and evaluated for antiproliferative activities against a panel of human cancer cells. The 2-aminobenzamide series inhibitors generally had the potency in cell growth inhibitions comparable to that of MS-275. Among them, the compound having a (3,4-difluorobenzyl)(2-hydroxyethyl)amino group at one end and a 2-aminobenzamide group at the other of molecule showed the most promising profile as an anticancer drug candidate, since it had a comparatively low toxicity as did MS-275 against a normal fibroblast cell CCD-1059SK. Additionally, the derivative exhibited a high recovery in human plasma stability test.

Magnetic Carbon Nanotubes: Synthesis by Electrostatic Self-Assembly Approach and Application in Biomanipulations

Magnetic multiwalled carbon nanotubes (MWNTs) were facilely prepared by the electrostatic self-assembly approach. Poly(2-diethylaminoethyl methacrylate) (PDEAEMA) was covalently grafted onto the surfaces of MWNTs by MWNT-initiated in situ atom transfer radical polymerization (ATRP) of 2-diethylaminoethyl methacrylate (DEAEMA). The PDEAEMA-grafted MWNTs were quaternized with methyl iodide (CH(3)I), resulting in cationic polyelectrolyte-grafted MWNTs (MWNT-PAmI). Magnetic iron oxide (Fe(3)O(4)) nanoparticles were loaded onto the MWNT surfaces by electrostatic self-assembling between MWNT-PAmI and Fe(3)O(4), affording magnetic nanotubes. The assembled capability of the nanoparticles can be adjusted to some extent by changing the feed ratio of Fe(3)O(4) to MWNT-PAmI. The obtained magnetic nanotubes were characterized with TEM, EDS, STEM, and element mapping analyses. TEM and EDS measurements confirmed the nanostructures and the components of the resulting nanoobjects. The magnetic nanotubes were assembled onto sheep red blood cells in a phosphate buffer solution, forming magnetic cells. The blood cells attached with or without magnetic nanotubes can be selectively manipulated in a magnetic field. These results promise a general and efficient strategy to magnetic nanotubes and the fascinating potential of such magnetic nanoobjects in applications of bionanoscience and technology.

Dynamics of disklike clusters formed in a magnetorheological fluid under a rotational magnetic field

We investigate the cluster formations and dynamics in a magnetorheological fluid under a rotational magnetic field focusing on the case of a relatively high volume fraction. We find that isotropic disklike clusters, which rotate more slowly than the field rotation, are formed at low Mason numbers (the ratio of viscous to magnetic forces) and, what is more, we show short rod clusters, which rotate stably thanks to the low Mason numbers and circulate along the surface of the disklike clusters. The circulation velocity of the surface particles is much higher than the rotational surface velocity of the rigid disklike clusters.

Technical note: DNA typing for ovine MHC DRB1 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)

The ovine major histocompatibilty complex (Ovar) class II DRB1 second exon was amplified by polymerase chain reaction (PCR) from DNA samples of 52 Suffolk sheep. Polymerase chain reaction products were characterized by the restriction fragment length polymorphism (RFLP) technique using nine restriction enzymes, RsaI, HaeIII, SacI, SacII, DdeI, NciI, Hin1I, EcoRI, and BstNI, yielding 13 types. Sequencing of cloned PCR products identified 16 Ovar-DRB1 alleles. Collectively, all PCR-RFLP patterns exactly matched those predicted from DNA sequences. These findings strongly indicate that the PCR-RFLP method using a combination of nine restriction endonucleases is a very powerful tool in Ovar typing.

Threonyl-tRNA synthetase of archaea: importance of the discriminator base in the aminoacylation of threonine tRNA

To investigate the contribution of the discriminator base of archaeal tRNA(Thr) in aminoacylation by threonyl-tRNA synthetase (ThrRS), cross-species aminoacylation between Escherichia coli and Haloferax volcanii, halophilic archaea, was studied. It was found that E. coli ThrRS threonylated the H. volcanii tRNA(Thr) but that E. coli threonine tRNA was not aminoacylated by H. volcanii ThrRS. Results of a threonylation experiment using in vitro mutants of E. coli threonine tRNA showed that only the mutant tRNA(Thr) having U73 was threonylated by H. volcanii ThrRS. These findings indicate that the discriminator base U73 of H. volcanii tRNA(Thr) is a strong determinant for the recognition by ThrRS.

Recognition of tRNA by aminoacyl-tRNA synthetase from hyperthermophilic archaea, Aeropyrum pernix K1

To study the recognition sites of tRNA for archaeal aminoacyl-tRNA synthetase, several aminoacyl-tRNA synthetase genes from hyperthermophilic archaeon, Aeropyrum pernix K1 were cloned and expressed. All the expressed enzymes showed extreme thermostability. Expressed threonyl-tRNA synthetase threonylated not only archaeal (A. pernix and Haloferax volcanii) threonine tRNAs but also Escherichia coli threonine tRNA. However, threonyl-tRNA synthetase from H. volcanii did not threonylate E. coli threonine tRNA.