Monitoring the endocytosis of bovine serum albumin based on the fluorescence lifetime of small squaraine dye in living cells

Fangrui Lin; Pintu Das; Yihua Zhao; Binglin Shen; Rui Hu; Feifan Zhou; Liwei Liu; Junle Qu

doi:10.1364/BOE.11.000149

Monitoring the endocytosis of bovine serum albumin based on the fluorescence lifetime of small squaraine dye in living cells

Biomed Opt Express. 2019 Dec 9;11(1):149-159. doi: 10.1364/BOE.11.000149. eCollection 2020 Jan 1.

Authors

Fangrui Lin¹, Pintu Das¹, Yihua Zhao¹, Binglin Shen¹, Rui Hu¹, Feifan Zhou¹, Liwei Liu^{1

2}, Junle Qu^{1

3}

Affiliations

¹ Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China.
² liulw@szu.edu.cn.
³ jlqu@szu.edu.cn.

Abstract

Bovine serum albumin (BSA) has a wide range of physiological functions involving the binding, transportation, and delivery of fatty acids, porphyrins, bilirubin, steroids, etc. In the present study, we prepared a small squaraine dye (SD), which can selectively detect BSA using fluorescence lifetime imaging microscopy (FLIM), to monitor the endocytosis of BSA in live cultured cells in real time. This approach revealed that BSA uptake is concentration-dependent in living cells. Furthermore, we used paclitaxel (PTX), a chemotherapeutic drug, to influence the endocytosis of BSA in living cells. The results demonstrated that the endocytic rate was clearly reduced after pretreatment with 0.4 µM PTX for 2 h. The present study demonstrates the potential value of using the fluorescence lifetime of SD to detect BSA concentration and study the physiological mechanism of chemotherapeutic drugs.