Exosome precipitation techniques are based on exosomes aggregating together when present in precipitating agents. In this technique, an aqueous solution is used to induce aggregation and precipitation of exosomes from the solution. The isolated exosome is then further purified for downstream applications. 

While exosome precipitation techniques are simple, scalable, and offer a relatively high yield, the downsides include lower purity and specificity due to potential co-precipitation of soluble non-exosomal proteins and potential alteration of exosome properties and cargo molecules during the precipitation process.