Diagnosis of cancer in the early stages requires sensitive magnetic resonance (MR) probes to detect low concentrations of magnetic substances. In this study, ultrasensitive magnetic resonance contrast agents (UMRCAs) composed of magnetic nanocrystals and amphiphilic block copolymers were synthesized for cancer detection using polyethylene glycol and fatty acid. The chemical structures and the compositions of PEGylated magnetic nanoparticles were analyzed. UMRCAs displayed remarkable colloidal stability and high sensitivity as MR probes. Furthermore, UMRCAs exhibited low cytotoxicity and excellent cancer detection ability in an in vivo animal model.

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Novel multifunctional magnetic polycation drug carriers (MPDCs) were synthesized to provide simultaneous magnetically targeted cancer therapy and diagnosis via magnetic resonance imaging (MRI). The MPDCs consist of ultra-sensitive magnetic nanocrystals as MR probes and for magnetic targeting, and a chemotherapeutic agent encapsulated in poly(hexadecylcyanoacrylate) (PHDCA) nanoparticles. The PHDCA nanoparticles were further coated with polycationic polyethylenimine (PEI) to enhance cellular uptake efficiency. The MPDCs demonstrated ultra-sensitivity via MRI and sufficient magnetic mobility under an external magnetic field. Drug loading efficiency and release kinetics were also investigated. From the cell viability data, the MPDCs were nontoxic and the doxorubicin hydrochloride (DOX)-loaded MPDCs exhibited excellent tumorcidal efficacy.

Chana series are new chalcone derivatives. To evaluate the possibility of Chana series as therapeutic agents of type 2 diabetes, the inhibitory effects of Chana series on the activities of α-glucosidase and DPP-4 were investigated using in vitro enzyme assays, and their effects on adipocyte differentiation were investigated in C3H10T1/2 cells. Chana 1 and Chana 7 among the Chana series showed significant inhibition of α-glucosidase activity. In DPP-4 enzyme assay, Chana 1 exhibited the highest inhibitory activity while Chana 7 did not. In MTT assay, Chana 1 did not show significant cytotoxicity up to a concentration of 250 μM, whereas cytotoxicity was observed with Chana 7 at a concentration of 300 μM. In addition, Chana 1 induced adipocyte differentiation. Therefore, Chana 1 showed inhibitory effects on α-glucosidase and DPP-4 as well as a stimulatory effect on adipocyte differentiation, suggesting that Chana 1 may be a potential beneficial agent for the treatment of type 2 diabetes. [BMB reports 2011; 44(6): 410-414]