鱼明胶作为卤化银纳米粒子载体的研究

采用的鱼明胶样品是从深海鱼的鱼皮提取而得,在成份和物理性质方面鱼明胶与通常使用的动物明胶有显著的差别.研究表明,鱼明胶的蛋白成分中α组分占绝对优势,且其中分子量较小的α2组分又比分子量较大的α1组分含量高得多.在鱼明胶中几乎没有分子量最大的γ组分.其氨基酸残基中,脯氨酸和羟脯氨酸的含量比动物胶低,而蛋氨酸含量却明显高于后者.鱼明胶还具有较低的胶凝温度.这些特点可能使之适宜作为分散介质来制备AgBrI纳米粒子乳剂.此外,鱼明胶中含有较多含硫物质,而且杂质铁主要以三价形式存在.并且进一步利用鱼明胶作为保护载体,在广泛的胶银比(即明胶量与银量之比值)范围(从8∶ 1到4∶ 1)获得了平均粒径为14 nm的 AgBrI纳米粒子乳剂.该乳剂具有良好的单分散性和热稳定性.对纳米粒子乳剂进行硫-金协同敏化可以提高其感光度.若适当增加敏化剂用量和适当延长敏化时间这种协同敏化作用的效果更好.

Study of Fish Gelatin as a Carrier of Silver Halide Nanoparticles

Fish gelatin is extracted from the skin of deep water fish. It is different from general bovine gelatin in conformation, components and physical characters. It is characteristic for fish gelatin conformation thatαchains are major in which the content ofα2component with lower molecular weight is much more than that ofα1one;γcomponent which exists in general bovine gelatin is not found here. Fish gelatin contains less of proline and hydroxyproline, which results in lower gelling temperature. However, the amount of methionine residues in fish gelatin is obviously more than that in bovine gelatin. These properties of fish gelatin is favorable for preparation of photographic emulsion containing AgBrI nanoparticles. Besides, it is found that more sulfur containing components occur and dominant state of iron is one with +3 valence in fish gelatin. In the present study of fish gelatin as the silver halide carrier, AgBrI nanoparticles with average size of 14 nm are made over a wide range of ratio of gelatin to silver from 8∶1 to 4∶1. These particles possess satisfactory monodispersity and thermostability. The sulfur-plus-gold sensitization causes the photosensitivity of this nanoparticle AgBrI emulsion to rise. It is especially interesting that increases of sensitizer amount and prolongation of sensitizing time enhance this synergistic sensitization.