We describe the synthesis and characterization of metal-chelating polymers with a degree of polymerization of 67 and 79, high DTPA functionality, Mw/Mn ≤ 1.17, and a maleimide as an orthogonal functional group for conjugation to antibodies. The polymeric disulfide form of the DPn = 79 DTPA polymer was analyzed by thermogravimetric analysis to determine moisture and sodium-ion content, and by isothermal titration calorimetry (ITC) to determine the Gd3+ binding capacity. These results showed each chain binds 68 ± 7 Gd3+ per chain. Secondary goat anti-mouse IgG was covalently labeled with the maleimide form of the DTPA polymer (DPn = 79) carrying 159Tb. Conventional ICP-MS analysis of this conjugate showed each antibody carried an average of 161 ± 4 159Tb atoms. This result was combined with the ITC result to show there are an average of 2.4 ± 0.3 polymer chains attached to each antibody. Eleven monoclonal primary antibodies were labeled with different lanthanide isotopes using the same labeling methodology. Single cell analysis of whole umbilical cord blood stained with a mixture of 11 metal-tagged antibodies was performed by mass cytometry.

Plant molecular farming: challenges and opportunities.

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We compare the influence of humidity on the polymer diffusion rate in films formed from two different polymer latex samples whose polymers have the same glass transition temperature (T g ≈ 12 °C) but different hydrophilicity: poly(butyl acrylate-co-methyl methacrylate), P(BA-MMA), and the more hydrophobic poly(2-ethylhexyl acrylate-co-tert-butyl methacrylate), P(EHA-tBMA). The diffusion process was monitored by fluorescence resonance energy transfer (FRET) at 25 °C and at 0, 23, 54, 85 and 98% relative humidities. The results show that the polymers diffused more rapidly in films aged at higher humidities, and thus were characterized by higher apparent diffusion coefficients (D app ). By performing a master curve analysis, we obtained humidity related shift factors (a H ). Not all the water taken up by these latex films contributes to enhance diffusion rates. Some of the water absorbed at high humidities is present in the form of water pools and microcavities (free water) and does not actively contribute to plasticization. We used FTIR spectra to obtain information about how water resides in the copolymer films. Although water is poorly miscible with most polymers, our results show that water molecules dispersed molecularly among the chains are highly efficient as a plasticizer and a promoter of polymer diffusion in latex films.

Concern for the environment has been driving major changes in the coatings industry.