Also, since tissue samples after expansion are 99% water, they can be nearly transparent and tricky to see.

此外，由于膨胀后的组织样本 99% 是水，因此它们几乎透明且难以看到。

To this problem Dr Boyden has devised a new solution: adding the fluorescent markers after expansion of the sample, rather than before.

针对这个问题，Boyden 博士设计了一个新的解决方案：在样本扩展之后添加荧光标记，而不是之前。