Development of a growth-hormone-conjugated nanodiamond complex for cancer therapy.

It is highly desirable to develop a therapeutic, observable nanoparticle complex for specific targeting in cancer therapy. Growth hormone (GH) and its antagonists have been explored as cancer cell-targeting molecules for both imaging and therapeutic applications. In this study, a low toxicity, biocompatible, therapeutic, and observable GH-nanoparticle complex for specifically targeting growth hormone receptor (GHR) in cancer cells was synthesized by conjugating GH with green fluorescence protein and carboxylated nanodiamond. Moreover, we have shown that this complex can be triggered by laser irradiation to create a "nanoblast" and induce cell death in the A549 non-small-cell lung cancer cell line via the apoptotic pathway. This laser-mediated, cancer-targeting platform can be widely used in cancer therapy.

Highly electrostatically-induced detection selectivity and sensitivity for a colloidal biosensor made of chitosan nanoparticle decorated with a few bare-surfaced gold nanorods.

Metallic nanoparticles have been utilized as an analytical tool to detecting a wide variety of organic analytes. Among them, gold nanoparticles demonstrating outstanding surface plasmonic resonance property have been well recognized and received wide attention for plasmon-based sensing applications. However, in literature, gold-based nanosensor has to be integrated with specific "ligand" molecule in order to gain molecular recognition ability. However, "ligand" molecules, included proteins, peptides, nucleic acids, etc. are expensive and vulnerable to environmental change, in the meantime, anchoring procedure of the "ligand" molecules to gold surface may be cost-ineffective and endangered to the ligand's activity, making a final analytic probe less reliable and risk in production capability. Here, we develop a new approach by designing a colloid-type sensor using a few "bare" Au nanorods deposited on the surface of a colloidal chitosan carrier. By tuning the solution pH, the resulting colloidal nanoprobe is capable of detecting proteins, i.e., human serum albumin and lysozyme, with high specificity and sensitivity. This new approach allows a new type of the molecular probes to be well manipulated to monitor important biomolecules for medical detection, diagnosis, and bioengineering applications.

Synthesis of apolipoprotein B lipoparticles to deliver hydrophobic/amphiphilic materials.

To develop a drug delivery system (DDS), it is critical to address challenging tasks such as the delivery of hydrophobic and amphiphilic compounds, cell uptake, and the metabolic fate of the drug delivery carrier. Low-density lipoprotein (LDL) has been acknowledged as the human serum transporter of natively abundant lipoparticles such as cholesterol, triacylglycerides, and lipids. Apolipoprotein B (apo B) is the only protein contained in LDL, and possesses a binding moiety for the LDL receptor that can be internalized and degraded naturally by the cell. Therefore, synthetic/reconstituting apoB lipoparticle (rABL) could be an excellent delivery carrier for hydrophobic or amphiphilic materials. Here, we synthesized rABL in vitro, using full-length apoB through a five-step solvent exchange method, and addressed its potential as a DDS. Our rABL exhibited good biocompatibility when evaluated with cytotoxicity and cell metabolic response assays, and was stable during storage in phosphate-buffered saline at 4 °C for several months. Furthermore, hydrophobic superparamagnetic iron oxide nanoparticles (SPIONPs) and the anticancer drug M4N (tetra-O-methyl nordihydroguaiaretic acid), used as an imaging enhancer and lipophilic drug model, respectively, were incorporated into the rABL, leading to the formation of SPIONPs- and M4N- containing rABL (SPIO@rABL and M4N@rABL, respectively). Fourier transform infrared spectroscopy suggested that rABL has a similar composition to that of LDL, and successfully incorporated SPIONPs or M4N. SPIO@rABL presented significant hepatic contrast enhancement in T2-weighted magnetic resonance imaging in BALB/c mice, suggesting its potential application as a medical imaging contrast agent. M4N@rABL could reduce the viability of the cancer cell line A549. Interestingly, we developed solution-phase high-resolution transmission electron microscopy to observe both LDL and SPIO@rABL in the liquid state. In summary, our LDL-based DDS, rABL, has significant potential as a novel DDS for hydrophobic and amphiphilic materials, with good cell internalization properties and metabolicity.

A unique and potent protein binding nature of liposome containing polyethylenimine and polyethylene glycol: a nondisplaceable property.

Most of the currently available targeting vectors are produced via the linkage of targeting molecules. However, the coupling process is complicated, and the covalent linkage may attenuate the activity of certain targeting molecules. In this study, we have developed a cationic liposome complexed with polyethylenimine and polyethylene glycol polymers (LPPC) that can capture various proteins without covalent conjugation. Characterizations of prepared LPPC revealed that the maximal-binding capacity was about 170 µg of bovine serum albumin to 40 µg of sphere-shaped LPPC (180 nm). The proteins were essentially located at or near the surface when analyzed by atomic force or transmission electron microscopy. We demonstrate that polyethylenimine was an essential component to bind the proteins. Upon the saturation of captured proteins, a given protein could not be displaced by other additional proteins and still retained its biological activity. Using a variety of functional proteins, we show some typical examples of the utility of incorporated beta-glucuronidase and antibodies onto the LPPC. The beta-glucuronidase can be used for the study of antigen-antibody interactions, whereas in studies with the antibody complex, we used anti-CD3 as an agonist to stimulate the proliferation of peripheral blood mononuclear cells via a receptor-mediated mechanism and anti-VEGFR for cell staining. In conclusion, the prepared LPPC can provide a platform to capture biologically and biochemically functional proteins on its surface for various applications, such as cell signaling, cell profiling, noncovalent enzyme-linked immunoassays, and others not mentioned.