A water-insoluble polymeric particle has an inner core comprising a detectable tracer material distributed in a first polymer for which the tracer material has a high affinity. This first polymer has a glass transition temperature (Tg₁) less than 100°C. The particle also has an outer shell comprising a second polymer for which the tracer material has substantially less affinity relative to said first polymer. This second polymer has a glass transition temperature (Tg₂) which is greater than or equal to the term [Tg₁-10°C]. It also contains groups which are either reactive with free amino or sulfhydryl groups of an immunoreactive species or which can be activated for reaction with such groups. Such a species can be covalently attached to this particle to form an immunoreactive reagent which is useful in analytical elements and various analytical methods including immunological methods, for example, agglutination assays.
一种不溶于
水的聚合物粒子有一个内核,内核包括分布在第一种聚合物中的可检测示踪材料,该示踪材料对第一种聚合物具有很高的亲和力。第一种聚合物的
玻璃化温度 (Tg₁) 小于 100°C。颗粒还有一个由第二种聚合物组成的外壳,相对于第一种聚合物,示踪材料对第二种聚合物的亲和力要小得多。第二种聚合物的
玻璃化温度(Tg₂)大于或等于[Tg₁-10°C]。它还含有可与免疫活性物质的游离
氨基或巯基反应的基团,或可激活与这些基团反应的基团。这种物质可以共价连接到这种微粒上,形成免疫活性试剂,这种试剂可用于分析元素和各种分析方法,包括免疫学方法,例如凝集试验。