Monitoring the physicochemical characteristics of nanoparticles following internalisation by cells is a vital step in understanding their biological impact and toxicity. Here, the feasibility of a methodology utilising gentle enzymatic lysis of cells containing internalised particles and direct analysis of the lysates for the particle size, agglomeration state and concentration, is investigated. It is demonstrated that following internalisation, all types of studied silica particles partially agglomerate/aggregate, with the degree and rate of the observed transformation closely correlated with the initial particle surface chemistry. Several different particle populations are noted and characterised in terms of their size and concentration. Good agreement between different complementary techniques is reached in terms of the average particle diameter. Particle concentration is determined here with techniques capable of mass and number-based measurements, with limitations of approaches utilising signal conversion to equivalent particle numbers identified and discussed.

中文翻译：

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二氧化硅纳米颗粒在被细胞内化后的变化：大小，聚集/团聚状态，基于质量和数量的浓度†

在细胞内化后，监测纳米颗粒的理化特性是了解其生物学影响和毒性的至关重要的一步。在此，研究了一种方法的可行性，该方法利用含有内在颗粒的细胞的温和酶解作用并直接分析裂解物的粒径，团聚状态和浓度。已经证明，在内部化之后，所有类型的研究二氧化硅颗粒都会部分聚集/聚集，观察到的转变的程度和速率与初始颗粒表面化学性质密切相关。记录了几种不同的粒子群，并根据其大小和浓度进行了表征。就平均粒径而言，不同的补充技术之间达成了良好的一致性。此处的颗粒浓度是通过能够进行基于质量和数量的测量的技术来确定的，但受限于将信号转换为已确定和讨论的等效颗粒数的方法。