Magnetic separation of melanoma-specific cytotoxic T lymphocytes from a vaccinated melanoma patient's blood using MHC/peptide complex-conjugated bacterial magnetic particles

Current Designs and Developments of Fucoidan-based Formulations for Cancer Therapy

BACKGROUND

Natural nanostructure materials have been involved in antitumor drug delivery systems due to their biocompatibility, biodegradation, and bioactive properties.

METHODS

These materials have contributed to advanced drug delivery systems in the roles of both bioactive compounds and delivery nanocarriers. Fucoidan, a valuable ocean material used in drug delivery systems, has been exploited in research on cancer and a variety of other diseases.

RESULTS

Although the uniqueness, structure, properties, and health benefits of fucoidan have been mentioned in various prominent reviews, current developments and designs of fucoidan-based formulations still need to be assessed to further develop an effective anticancer therapy. In this review, current important formulations using fucoidan as a functional material and as an anticancer agent will be discussed. This article will also provide a brief principle of the methods that incorporate functional nanostructure materials in formulations exploiting fucoidan.

CONCLUSION

Current research and future perspectives on the use of fucoidan in anticancer therapy will advance innovative and important products for clinical uses.

Magnetic nanoparticles for the manipulation of proteins and cells

In the rapidly developing areas of nanobiotechnology, magnetic nanoparticles (MNPs) are one type of the most well-established nanomaterials because of their biocompatibility and the potential applications as alternative contrast enhancing agents for magnetic resonance imaging (MRI). While the development of MNPs as alternative contrast agents for MRI application has moved quickly to testing in animal models and clinical trials, other applications of biofunctional MNPs have been explored extensively at the stage of qualitative or conceptual demonstration. In this critical review, we summarize the development of two straightforward applications of biofunctional MNPs--manipulating proteins and manipulating cells--in the last five years or so and hope to provide a relatively comprehensive assessment that may help the future developments. Specifically, we start with the examination of the strategy for the surface functionalization of MNPs because the applications of MNPs essentially depend on the molecular interactions between the functional molecules on the MNPs and the intended biological targets. Then, we discuss the use of MNPs for manipulating proteins since protein interactions are critical for biological functions. Afterwards, we evaluate the development of the use of MNPs to manipulate cells because the response of MNPs to a magnetic field offers a unique way to modulate cellular behavior in a non-contact or "remote" mode (i.e. the magnet exerts force on the cells without direct contact). Finally, we provide a perspective on the future directions and challenges in the development of MNPs for these two applications. By reviewing the examples of the design and applications of biofunctional MNPs, we hope that this article will provide a reference point for the future development of MNPs that address the present challenges and lead to new opportunities in nanomedicine and nanobiotechnology (137 references).

Magnetite-loaded fluorine-containing polymeric micelles for magnetic resonance imaging and drug delivery

Magnetite (Fe(3)O(4)) - loaded polymer micelles (denoted as "magnetomicelles") are produced by self-assembly of fluorine-containing amphiphilic poly(HFMA-g-PEGMA) copolymers with oleic acid modified Fe(3)O(4) nanoparticles in an aqueous medium. The oleic acid modified Fe(3)O(4) nanoparticles form small clusters in the poly(HFMA-g-PEGMA) micelles with a mean diameter of 100 nm and the magnetomicelles show high stability in an aqueous medium due to the high hydrophobic fluorine segments in graft copolymers enhance the stability of the micelles. The magnetomicelles also show good cytocompatibility based on the MTT cytotoxicity assay and possess paramagnetic properties with saturation magnetization of 17.14 emu/g.Their good stability, cytocompatibility, and paramagnetic properties render the materials attractive in drug delivery and in vivo magnetic resonance imaging (MRI) applications. Controlled release of hydrophobic drug-5-fluorouracil is achieved from the magnetomicelles with a loading efficiency of 20.94 wt%. The magnetomicelles have transverse relaxivity rates (r(2)) of 134.27 mM(-1) s(-1) and exhibit high efficacy as a negative MRI agent in T(2)-weighted imaging. In vivo MRI studies demonstrate that the contrast between liver and spleen is enhanced by the magnetomicelles. These favorable properties suggest clinical use as nanocarriers in drug delivery applications and contrast agents in MRI.

Surface modification of magnetic nanoparticles using asparagines-serine polypeptide designed to control interactions with cell surfaces

Surface modification is an important part of the fabrication of nanoparticles that have specific properties and functions. Here we describe the development of a functional polypeptide and a simple available technology for surface modification of nanoparticles. A NS polypeptide, which is 100 amino acids composed of repeated units of four asparagine and one serine residue (NS), as a molecule for nanoparticle surface modification was designed. Modification of the surface of a magnetic nanoparticle with the NS polypeptide results in reduction of particle-particle and particle-cell interactions. When NS polypeptide is used in single fusion protein as a linker to display protein G on nanoparticles, the nanoparticle acquires the capacity to specifically bind target cells and to avoid nonspecific adsorption of non-target cells. This technology, incorporating a functional polypeptide, may represent a completely new strategy for surface modification of nanoparticles for use in a variety of cell-associated applications.

Amphiphilic comblike polymers enhance the colloidal stability of Fe(3)O(4) nanoparticles

Stable colloidal dispersions of magnetite (Fe(3)O(4)) nanoparticles (MNPs) were obtained with the inclusion of an amphiphilic comblike polyethylene glycol derivative (CL-PEG) as an amphiphilic polymeric surfactant. Both the size and morphology of the resulting CL-PEG-modified MNPs could be controlled and were characterized by transmission electron microscopy (TEM). The interaction between MNPs and CL-PEG was confirmed by the presence of characteristic infrared absorption peaks, and the colloidal stability of the nanoparticle dispersion in water was evaluated by long-term observation of the dispersion using UV-visible spectroscopy. SQUID measurements confirmed the magnetization of CL-PEG-modified MNPs. The zeta potential of the CL-PEG-modified MNPs showed a dramatic conversion from positive to negative in response to the pH of the surrounding aqueous medium due to the presence of carboxyl groups at the surface. These carboxyl groups can be used to functionalize the MNPs with biomolecules for biotechnological applications. However, regardless of surface electrostatics, the flexible, hydrophilic side chains of CL-PEG-modified MNPs prevented the approach of adjacent nanoparticles, thereby resisting aggregation and resulting in a stable aqueous colloid. The cytotoxicity of MNPs and CL-PEG-modified MNPs was evaluated by a MTT assay.

In vivo display of a multisubunit enzyme complex on biogenic magnetic nanoparticles

Magnetosomes are unique bacterial organelles comprising membrane-enveloped magnetic crystals produced by magnetotactic bacteria. Because of several desirable chemical and physical properties, magnetosomes would be ideal scaffolds on which to display highly complicated biological complexes artificially. As a model experiment for the functional expression of a multisubunit complex on magnetosomes, we examined the display of a chimeric bacterial RNase P enzyme composed of the protein subunit (C5) of Escherichia coli RNase P and the endogenous RNA subunit by expressing a translational fusion of C5 with MamC, a known magnetosome protein, in the magnetotactic bacterium Magnetospirillum gryphiswaldense. As intended, the purified C5 fusion magnetosomes, but not wild-type magnetosomes, showed apparent RNase P activity and the association of a typical bacterial RNase P RNA. Our results demonstrate for the first time that magnetosomes can be employed as scaffolds for the display of multisubunit complexes.