School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, USA.
J Colloid Interface Sci. 2011 Nov 1;363(1):137-44. doi: 10.1016/j.jcis.2011.07.047. Epub 2011 Jul 27.
A series of water-insoluble, biologically compatible dyes, meso-tetraphenylchlorin, meso-tetraphenylporphyrin and chlorophyll-a, were successfully incorporated into beads composed of linear polystyrene (PS) via a tunable combined swelling-diffusion process. Dyed PS beads were prepared by the addition of a dye solution in tetrahydrofuran to an aqueous suspension of 10 μm PS beads in the presence of a poly((ethylene glycol)-b-(propylene glycol)-b-(ethylene glycol)) block copolymer surfactant. The presence of surfactant was found to be beneficial to prevent particle aggregation, especially at tetrahydrofuran contents above 30%. Dye loading was shown to be tunable by simple adjustments in dye composition. Confocal fluorescence microscopy indicated that dyes were distributed uniformly throughout the entire PS bead, but heterogeneously with ~500 nm diameter droplets, indicative of a separate dye phase within the PS matrix. The stability of dyed beads, indicated by resistance to dye leaching in solvent, was found to be governed by the degree of swelling of PS in the solvent medium. Hence, no leaching was observed even when a good solvent for the dye was used (ethanol), as long as that solvent did not swell the carrier particle, PS. No leaching of dyes from the beads was observed during long-term (2 years) storage in water.
一系列的水溶性差、生物相容性好的染料，如间四苯基卟啉、间四苯基卟啉和叶绿素-a，通过可调的溶胀-扩散过程成功地掺入到由线性聚苯乙烯（PS）组成的珠体中。通过将染料溶液加入到含有 10 μm PS 珠体的水溶液中，并在聚（乙二醇）-b-（丙二醇）-b-（乙二醇）嵌段共聚物表面活性剂的存在下，制备了染色 PS 珠体。发现表面活性剂的存在有利于防止颗粒聚集，特别是在四氢呋喃含量高于 30%时。通过简单调整染料组成，可以对染料负载进行调节。共聚焦荧光显微镜表明，染料均匀分布在整个 PS 珠体中，但存在 500nm 左右的直径的液滴，表明在 PS 基质中有一个单独的染料相。染色珠体的稳定性，即抵抗溶剂中染料浸出的能力，由 PS 在溶剂介质中的溶胀程度决定。因此，即使使用染料的良溶剂（乙醇），只要该溶剂不溶胀载体颗粒 PS，就不会观察到染料浸出。在水中长期（2 年）储存过程中，也没有观察到染料从珠体中浸出。
