¹⁹F‑NMR, ¹H‑NMR, and Fluorescence Studies of Interaction between 5‑Fluorouracil and Polyglycerol Dendrimers

Polyglycerol dendrimers (PGDs), which exhibit a well-defined structure consisting of only glycerol units, were examined as a host molecule of 5-fluorouracil (5-Fu) used as a model anticancer drug. ¹⁹F- and ¹H-NMR titrations and fluorescence measurements were performed to estimate the molecular interaction between PGDs and 5-Fu in a buffer. Results of the NMR titrations revealed that PGD of generation 3 (PGD-G3) encapsulated 5-Fu in the buffer, whereas PGD-G2 and G1 partially incorporated 5-Fu molecule into the space. Fluorescent spectra of 5-Fu in the presence of PGD-G3 indicated that the diketo (lactam) form of 5-Fu changed to the enol-keto (lactim) form of 5-Fu, suggesting attraction of the imine proton of 5-Fu by ether oxygen of PGD-G3. Therefore, the encapsulation state of 5-Fu in PGDs at molecular level was modulated by the well-defined branched structure depending on the generation of PGDs

Temperature-induced recovery of a bioactive enzyme using polyglycerol dendrimers: correlation between bound water and protein interaction

<p>Enzyme application has gained importance over the past decade in bioprocess, biomedical, and pharmaceutical fields. We found that polyglycerol dendrimers (PGDs), which are biocompatible molecules, can recover alcohol dehydrogenase (ADH) from aqueous solution under elevated temperature. A low concentration of PGD (5 wt.%) is sufficient for the recovery of high enzymatic activity, although a high concentration (25–75 wt.%) of glycerol is generally required to stabilize ADH. The enzymatic activity of ADH in suspension with PGDs is over 60% but it is only 10% in that with glycerol. The results of osmolarity and spin-lattice relaxation time (<i>T</i>₁) of water measurements in the presence of PGDs suggest that increased amounts of bound water to PGD molecules trigger aggregation along with the direct interaction with ADH. PGDs therefore represent good potential additives for direct recovery of enzymes from aqueous solutions.</p

Amphiphilic Polymerizable Porphyrins Conjugated to a Polyglycerol Dendron Moiety as Functional Surfactants for Multifunctional Polymer Particles

An amphiphilic polyglycerol dendron (PGD) conjugated porphyrin (PGP) bearing a polymerizable group was successfully synthesized. The PGP was used as an effective surfactant in emulsion and microsuspension polymerization systems to prepare styrene and methacrylate polymer particles, and the use of PGP provided the simple polymer particles with fluorescence derived from the metalloporphyrin and high colloidal stability due to the PGD. Furthermore, based on confocal laser scanning microscopy, we observed that the particles spontaneously formed a core–shell morphology with the PGP localized in the shell region during the polymerization and demonstrated drug loading in the shell region using rhodamine B as a model drug. The results indicate that the use of the functional surfactant PGP led to the preparation of multifunctional polymer particles from simple monomer species, and the resulting particles possessed high colloidal stability, fluorescence, and drug loading capability

Fabrication of Carboxylated Silicon Nitride Sensor Chips for Detection of Antigen–Antibody Reaction Using Microfluidic Reflectometric Interference Spectroscopy

In this study, we report label-free detection of alpha-fetoprotein (AFP), which has been used as a biomarker for hepatocellular carcinoma, by a microfluidic reflectometric interference spectroscopy (RIfS) system adopting a simple halogen light source and an inexpensive silicon-based sensor chip. Introduction of carboxy groups on a silicon nitride sensor chip to immobilize anti-AFP monoclonal antibody (anti-AFP) was carried out simply by immersion in aqueous solution containing triethoxysilylpropylmaleamic acid bearing a carboxy group and a silanol group. The RIfS system with the anti-AFP-immobilized sensor chip was found to give a reversible response through 100 on/off cycles using a regeneration buffer with high reproducibility (coefficient of variation (CV) = 5.7%). The limit of detection (LOD) of AFP was 100 ng mL^–1, and the measurement range spanned 3 orders of magnitude. Furthermore, the sensor chip showed no cross-reactivity with human serum albumin, Immunoglobulin G, transferrin, or fibrinogen at 100 μg mL^–1 without the use of blocking reagents such as bovine serum albumin. Consequently, the proposed RIfS system is a potentially effective tool for biomarker detection and in vitro diagnostics