During the past five decades, various types of chemistries have been used for conjugation of molecules such as antibodies, peptides, proteins or other reactive ligands to the surface of liposomes. In general, the conjugation can be achieved through the N-terminus, the C-terminus or the available sulfur (e.g. Fab’ fraction or thiolated antibodies). Not all chemistries have the same yield and efficiency of conjugation and often reproducing biocompatible batches can be a challenge.
Copper-free click chemistry is a fairly new chemistry that has been commercialized during the past few years. More and more click chemistry-based reagents are becoming available commercially which makes the formulation development much easier for scientists. The great advantage of this chemistry is biocompatibility since no cytotoxic copper catalyst is required. By far, click chemistry is the most efficient and easiest conjugation chemistry available for coupling of antibodies and other reactive ligands to the surface of the liposomes. The conjugation chemistry is based on the reaction of the dibenzocyclooctyne (DBCO) reagent with an azide linker to form a stable triazole. DBCO moiety can be on the antibody and azide moiety can be on liposomes and vice versa. Here, azide moiety is on the liposome and DBCO moiety is on the antibody, protein or peptide.
There are many commercialized reagents that can be used for DBCO modification of proteins, peptides and antibodies. To see the list of commercialized reagents for DBCO modification see here.
For other reactive (PEGylated and non-PEGyalated products) ImmunoFluor™ products suitable for other types conjugation methods see here.
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希望知道如何购买的朋友告诉一下，谢谢。
一般来说，试剂盒曲线上的最小浓度是比较准确的，低于这个值因为与曲线是个“S"型结构有关，所以结果是有偏差的，是一种估算。再加上实验误差，所以达不到理想的效果。建议选择试剂盒时，应该看曲线上最小的浓度值，而不是试剂盒上写的灵敏度。
虽然酶活性调节ELISA方法的灵敏度目前并不十分理想，但在酶活性放大ELISA中，检测的灵敏度远比RIA高。根据质量作用定律。即免疫反应所形成的免疫复合物量与反应物浓度成正比。推测所检测的待测物分子数为1。已知1个摩尔浓度含6.02×1023个分子，那么理论推测酶活性放大ELISA方法的最低检测限可达1.7×10-24mol/L。虽然在实际应用中由于反应条件和试剂纯度以及仪器精度等因素的影响，往往达不到这个水平(大于104个分子)，但表明ELISA在灵敏度方面的改进潜力是很大的。
