title: Polydiacetylene-enclosed near-infrared fluorescent semiconducting polymer dots for bioimaging and sensing.
abstract: Semiconducting polymer dots (P-dots) recently have emerged as a new type of ultrabright fluorescent probe with promising applications in biological imaging and detection. With the increasing desire for near-infrared (NIR) fluorescing probes for in vivo biological measurements, the currently available NIR-emitting P-dots are very limited and the leaching of the encapsulated dyes/polymers has usually been a concern. To address this challenge, we first embedded the NIR dyes into the matrix of poly[(9,9-dioctylfluorene)-co-2,1,3-benzothiadiazole-co-4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole] (PF-BT-DBT) polymer and then enclosed the doped P-dots with polydiacetylenes (PDAs) to avoid potential leakage of the entrapped NIR dyes from the P-dot matrix. These PDA-enclosed NIR-emitting P-dots not only emitted much stronger NIR fluorescence than conventional organic molecules but also exhibited enhanced photostability over CdTe quantum dots, free NIR dyes, and gold nanoclusters. We next conjugated biomolecules onto the surface of the resulting P-dots and demonstrated their capability for specific cellular labeling without any noticeable nonspecific binding. To employ this new class of material as a facile sensing platform, an easy-to-prepare test paper, obtained by soaking the paper into the PDA-enclosed NIR-emitting P-dot solution, was used to sense external stimuli such as ions, temperature, or pH, depending on the surface functionalization of PDAs. We believe these PDA-coated NIR-fluorescing P-dots will be very useful in a variety of bioimaging and analytical applications.
authors.affiliation: Department of Chemistry, National Sun Yat-sen University , 70 Lien Hai Road, Kaohsiung, Taiwan 80424.
authors.forename: Pei-Jing
authors.initials: PJ
authors.lastname: Wu
authors.forename: Shih-Yu
authors.initials: SY
authors.lastname: Kuo
authors.forename: Ya-Chi
authors.initials: YC
authors.lastname: Huang
authors.forename: Chuan-Pin
authors.initials: CP
authors.lastname: Chen
authors.forename: Yang-Hsiang
authors.initials: YH
authors.lastname: Chan
mesh_terms: D015374:Biosensing Techniques; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D011108:Polymers / Q000737:chemistry; D053279:Polyynes / Q000737:chemistry*; D012666:Semiconductors; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D011108:Polymers; D053279:Polyynes