HPMA (103.6
mg, 0.72 mmol), MA-SS-AMD (6 ) (347 mg, 0.36 mmol), AIBN
(11.3 mg), and DMF (2 mL) were added into a 5 mL ampule. After bubbling
with nitrogen for 30 min, the ampule was sealed and the mixture was
heated at 50 °C for 24 h. The polymer was precipitated into cold
diethyl ether, centrifuged, and dried in air for 4 h. The dried polymers
were mixed with trifluoroacetic acid (10 mL) and stirred at room temperature
for 3 h. After trifluoroacetic acid was removed under reduced pressure,
the remaining polymer solution was precipitated by dropwise addition
into cold diethyl ether. The polymer was isolated by filtration, dried
in vacuum, and then dissolved in water and dialyzed against 1 M HCl
followed by final lyophilization. The molecular weights and molecular
weight distribution of the polymers were determined by size-exclusion
chromatography (TSK-GEL PWXL column, Toshoh Bioscience)
equipped with a miniDAWN TREOS multi-angle static light scattering
detector (Wyatt) and Optilab T-rEX differential refractive index detector
(Wyatt) using 0.5 M sodium acetate buffer (pH 5) as the mobile phase.
mg, 0.72 mmol), MA-SS-AMD (
(11.3 mg), and DMF (2 mL) were added into a 5 mL ampule. After bubbling
with nitrogen for 30 min, the ampule was sealed and the mixture was
heated at 50 °C for 24 h. The polymer was precipitated into cold
diethyl ether, centrifuged, and dried in air for 4 h. The dried polymers
were mixed with trifluoroacetic acid (10 mL) and stirred at room temperature
for 3 h. After trifluoroacetic acid was removed under reduced pressure,
the remaining polymer solution was precipitated by dropwise addition
into cold diethyl ether. The polymer was isolated by filtration, dried
in vacuum, and then dissolved in water and dialyzed against 1 M HCl
followed by final lyophilization. The molecular weights and molecular
weight distribution of the polymers were determined by size-exclusion
chromatography (TSK-GEL PWXL column, Toshoh Bioscience)
equipped with a miniDAWN TREOS multi-angle static light scattering
detector (Wyatt) and Optilab T-rEX differential refractive index detector
(Wyatt) using 0.5 M sodium acetate buffer (pH 5) as the mobile phase.