Sulfo cyanine7 amine

Fluorescent alginate was prepared using carbodiimide chemistry according to established protocols^{23 (link),24 (link)} whereby Sulfo-Cyanine7 amine (5 mg, 0.0062 mmol; Lumiprobe) was dissolved under stirring in 15 mL of an alginate solution (10 mg/mL) formed in 0.1 M MES buffer at pH 6 (Thermo Fisher). Sulfo-NHS (41 mg, 0.19 mmol; Biovision) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC; 72.5 mg, 0.38 mmol; Sigma-Aldrich) were successively added, and the reaction mixture was stirred at room temperature for 20 h. The crude product was dialyzed against deionized water for 3 days (3.5 kDa MWCO) and lyophilized until dried.

A near-infrared (NIR) dye was conjugated with HAssLG for in vivo animal imaging studies. Fifty milligrams of HAssLG in 5 ml DMSO/water mixtures (4/1, v/v) was mixed with 3 mg of sulfo-cyanine7 amine (Lumiprobe Co., Florida, USA) with 1.2 equivalent moles of EDAC and NHS. This solution was then stirred for 24 h in room temperature. After that, the solution was dialyzed to remove unreacted dye with exchange of water at intervals of 2 h until the dye was not detected in the water. The detection of the dye and the contents in the polymer were measured with a UV spectrophotometer (UV-1601 UV-VIS spectrophotometer, Shimadzu, Kyoto, Japan) at 750 nm. The content of the NIR dye was 2.8 %, w/w. (Dye content (%, w/w) = (dye amount in the nanoparticles/total weight of the nanoparticles) × 100).