8-Arm PEG NHS

Synthesis, Characterization, and Functionalization of Gold Nanoparticles for Cancer Imaging

(polyethylene glycol), and cancer-specific mAb F19 was attached by means of NHS-EDC coupling chemistry taking advantage of a carboxylic acid group on the heterobifunctional PEG. These conjugates were completely stable and were characterized by a variety

聚乙二醇修饰反应类型

修饰，常有几个氨基被修饰，导致多态混合物的产生，即使只结合一个聚乙二醇，也可能结合在不同的氨基位点上，产生位点异构体。由于蛋白质只有一个末端氨基，因此对它的修饰可以减少多态混合物和位点异构体的产生，但修饰末端氨基的聚乙二醇反应时需使用硼氢氰化钠，有一定的毒性。氨基修饰最常用的修饰剂为SS-PEG、SC-PEG、SPA-PEG、NHS-PEG2和ALD-PEG等。 巯基修饰 活化半胱氨酸的巯基往往处于蛋白质的活性中心部位，位于蛋白质表面的自由巯基远少于氨基，因此修饰效率低下，修饰后蛋白活性损失较大

Microinjecting worms

phosphate, pH 7.5 30 mM potassium citrate, pH 7.5 Mix 10 mL 1M K phosphate pH 7.5, 5 ml 300 mM K citrate, pH 7.5, 10 g PEG, and ~25 ml H20, stir ~10 min to dissolve the PEG, and add more H20 to final volume of 50 ml. Note that the PEG