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论文类型： 期刊论文

发表时间： 2018-05-01

发表刊物： ANALYTICAL CHEMISTRY

收录刊物： PubMed、SCIE

卷号： 90

期号： 9

页面范围： 5803-5809

ISSN号： 0003-2700

摘要： A hallmark of cancer cells is a reversed transmembrane pH gradient, which could be exploited for robust and convenient intraoperative histopathological analysis. However, pathologically relevant pH changes are not significant enough for sensitive detection by conventional Henderson-Hasselbalch-type pH probes, exhibiting an acid base transition width of 2 pH units. This challenge could potentially be addressed by a pH probe with a reduced acid-base transition width (i.e., Hill-type probe), appropriate pKa, and membrane permeability. Yet, a guideline to allow rational design of such small-molecule Hill-type pH probes is still lacking. We have devised a novel molecular mechanism, enabled sequential protonation with high positive homotropic cooperativity, and synthesized small-molecule pH probes (PHXI-3) with acid-base transition ranges of ca. 1 pH unit. Notably, PHX2 has a pKa of 6.9, matching the extracellular pH of cancer cells. Also, PHX2 is readily permeable to cell membrane and allowed direct mapping of both intra-and extracellular pH, hence the transmembrane pH gradient. PHX2 was successfully used for rapid and high contrast distinction of fresh unprocessed biopsies of cancer cells from normal cells and therefore has broad potentials for intraoperative analysis of cancer surgery.