A water-soluble and biocompatible polymeric nanolabel based on naphthalimide grafted poly(acrylic acid) for the two-photon fluorescence imaging of living cells and C. elegans.
Polymeric nanoparticles (NPs) with two-photon (TP) activity were prepared by grafting a naphthalimide fluorophore onto poly(acrylic acid) to yield an amphiphilic polymer, which self-assembled in water. The NPs were characterized using various analytical techniques such as transmission electron microscopy, dynamic light scattering and spectroscopic measurements. The in vitro and in vivo biocompatibilities of the NPs were assessed by a cytotoxicity assay using HeLa cells and a feeding assay using Caenorhabditis elegans (C. elegans) as a small animal model, respectively. Finally, TP fluorescence imaging (FI) of living cells and C. elegans labelled with the NPs were observed by TP confocal microscopy. The experimental outcomes demonstrated that the NPs had sufficient water-dispersity and biocompatibility, had TP fluorescence activity, were resistant to pH variation and illumination, and were physically stable. TP FI revealed that the NPs could enter living cells and were primarily located in the cytoplasm. In addition, the NPs were ingested by C. elegans during the feeding process and were recognized and taken up by the active transport system of the intestinal cells. These findings indicated the feasibility of using the developed NPs as a nanolabel for TP FI. Moreover, with numerous modifiable carboxyl groups on its surface, the NPs could act as a platform to build multifunctional probes for potential applications in biosensing and assay labeling.
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, China. Electronic address: chirolab@whu.edu.cn.
Shucai
S
Liang
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, China.
Yongmei
Y
Liu
School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, China.
Ting
T
Fu
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, China.
Fan
F
Yang
School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, China.
Xiaohui
X
Chen
School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, China. Electronic address: guopyan2006@163.com.
Guoping
G
Yan
D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials; D017173:Caenorhabditis elegans / Q000737:chemistry*; D049329:Nanostructures; D053644:Naphthalimides / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D014867:Water
D000180:Acrylic Resins; D001672:Biocompatible Materials; D053644:Naphthalimides; D011108:Polymers; D014867:Water; C006903:carbopol 940
C. elegans; Living cell; Naphthalimide; Poly(acrylic acid); Polymeric nanoparticle; Two-photon fluorescence imaging