• P5 polypeptide is designed to form peptide-based nanofilaments (PFs) and has been demonstrated to exhibit excellent resistance to non-specific protein adsorption. Through a series of experiments, including turbidity measurement, high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), fluorescence resonance energy transfer (FRET), and transmission electron microscopy (TEM), it has been shown that P5Fs (nanofilaments formed by P5) have the lowest adsorption capacity for human serum albumin (HSA) among the studied PFs. This property is crucial for its application as a drug carrier, as it can reduce the formation of a biomolecule corona during circulation in the body, thereby minimizing the risk of being recognized and cleared by the immune system.
• In addition, P5Fs display a favorable biodistribution pattern. In vivo studies in mice have revealed that, compared to other PFs, P5Fs have a relatively lower accumulation in the lungs and a higher retention in the plasma one hour after injection. This distribution characteristic is beneficial for the circulation and penetration of drugs in the body, increasing the likelihood of the drug reaching the target site. Moreover, the docetaxel nanofilaments based on P5Fs (DP5Fs) have exhibited outstanding antitumor activity. In various tumor models, such as human breast cancer MCF - 7 tumors, human lung cancer A549 tumors, human colon cancer HT29 tumors, and human prostate cancer PC3 tumors, DP5Fs have demonstrated higher tumor inhibition rates and better survival benefits for animals than traditional drug formulations. These results suggest that P5 polypeptide holds great promise in the development of novel drug delivery systems and cancer therapies.

• Cai Y, Xu T, Zhu B, Chen J, Jiang L, Shan X, Rong R, Li Y, Yu Y, Gao X, Zhu HH, Zhang L, Zhang P, Li Y. Conformation Influences Biological Fates of Peptide-Based Nanofilaments by Modulating Protein Adsorption and Interfilament Entanglement. Adv Mater. 2024 Nov 28:e2409130. doi: 10.1002/adma.202409130. Epub ahead of print. PMID: 39610201.

三氟乙酸（Trifluoroacetic acid，简称 TFA）是高效液相色谱（简称 HPLC）纯化过程中常用的反离子。TFA 的存在可能会对肽的净重量、外观及溶解度产生影响，具体如下：

对净重量的影响：TFA 盐会增加产物的总质量。在大多数情况下，肽的含量占总重量的 80% 以上，剩余部分则为 TFA。

对溶解度的影响：TFA 盐通常能提高肽在水溶液中的溶解度。

在生物检测中的影响：对于大多数标准的体外检测，残留的 TFA 水平一般不会造成干扰。但需注意，在高灵敏度的细胞研究或生化研究中，需关注其存在可能带来的影响。

干品多肽的重量中不仅仅包含多肽，还包含有一些非肽的组份，如水、被吸收的溶剂、配位离子和盐等。肽的净含量是指肽在其中的重量百分比，这个百分比的数值范围很大，可能从50%到90%，取决于纯度、序列以及合成和纯化的方法，不要将肽的净含量和肽的纯度混为一谈，他们是两个完全不同的概念。纯度通常是通过HPLC测定的。纯度定义的是多肽样品中含正确序列的组分的百分比，而肽的净含量是指样品中肽类物质相对于总物质所占的百分比，肽的净含量通常是氨基酸组分分析或紫外分光法测定的，这个信息主要是在一些对肽的浓度很敏感的实验中，对计算肽的浓度是很重要的。