Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of stable spin probes, low frequency EPR imaging has recently allowed the use of large tissue samples or whole animals in vivo in the field of biology and medicine. It is normally necessary to introduce prior intravenous or intramuscular infusion of stable or slowly metabolizable non-toxic water-soluble paramagnetic materials, or stable implantable particulate materials as spin probes into the system. The classification and research progress of spin probes at present were described briefly. Three important potential approaches in water-soluble paramagnetic materials design including deuterated, site-specific and macromolecular conjugated nitroxides were also investigated.
YAN GuoPingPENG LeiJIAN ShuangQuanLI LiangBOTTLE Steven Eric
Magnetic resonance imaging (MRI) is a non-invasive clinical imaging modality,which has become widely used in the diagnosis of human diseases around the world.Some MRI exams include the use of contrast agents.The goal of an ideal MRI contrast agent involves the tissue-or organ-targeting materials with high relaxivity and specificity,low toxicity and side effects,suitable long intravascular duration and excretion time and high contrast enhancement with low doses,in vivo,all coupled to low overall cost.Dendrimers are synthetic,highly branched,mono-disperse macromolecules of nanometer dimensions.Properties associated with these dendrimers such as uniform size,water solubility,modifiable surface functionality and available internal cavities make them candidates for ideal carriers of MRI contrast agents.The research progress of the dendritic contrast agents is discussed.
YAN GuoPing AI ChaoWu LI Liang ZONG RongFeng LIU Fan
A series of polycarbonate copolymers were synthesized by microwave-assisted ring-opening polymerization of ε-caprolactone (CL) and 2-phenyl-5,5-bis(oxymethyl) trimethylene carbonate (PTC) with Tin (II) 2-ethylhexanoate as a catalyst. These copolymers obtained were detected by 1H NMR, FT-IR, UV, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and automatic contact angle meter. The influences of the feed molar ratio of monomers, catalyst concentration, reaction time and reaction temperature, as well as microwave irradiation power on the copolymerization process were also studied. In vitro degradation tests indicated that these polycarbonate copolymers possess the slow degradation rates and strong hydrophobicity. In vitro release profiles of 5-Fu from copolymers showed that copolymers have the steady drug release rates and good controlled release properties.
LU Ke YAN GuoPing CHEN Hui Li Liang AI ChaoWu YU XiangHua
