Cardiovascular Disease (CVD) accounts for 31% of deaths worldwide, making it the major cause of global mortality. The largest risk factor associated with CVD is a raised level of Low Density Lipoprotein (LDL) cholesterol level. However, only specific forms of post-translationally modified LDL cholesterol can accumulate in arteries and form plaques. Current mechanisms of reducing cholesterol levels mostly involve treatment with drugs called Statins, which are insufficient as they can cause severe side effects including abdominal distress and muscle pain and often do not reduce modified LDL to healthy levels. We generated a DNA Origami filter designed to selectively capture the most common forms of dangerous LDL cholesterol in the bloodstream - small and electronegative LDL cholesterol. Our filter is unfurled when not bound to its target, and curls upon attachment to small and electronegative LDL cholesterol, mimicking the action of fern leaves. Injection of the filter may be an effective means of capturing and excreting the worst forms of LDL cholesterol in patients. The filter could also be used outside the body as a means of detecting the presence of electronegative LDL cholesterol in blood samples.