@oristarA,
No--the sentence is not clearly written, but is immediately comprehensible to a native speaker:
Scientists found that by injecting skin cells with DNA proteins and a cocktail of molecules they could turn them into blood cells.
The obscure use of "with" means that DNA proteins and a cocktail of molecules is injected
into the skin cells, which may result in converting those cells into blood cells. As a matter of fact, i heard a news report about this on the radio last night.