The outer leaflet of the RBC plasma membrane is rich in polyunsaturated PC and saturated or monounsaturated SM . In contrast, the inner leaflet exhibits a nearly equal distribution of anionic lipids, such as PS and phosphatidylinositol (PI), alongside zwitterionic PC and PE . The inner leaflet's PC lipids are less unsaturated compared to those in the outer leaflet, while other lipids, including PE, PS, and PI, contain a higher proportion of polyunsaturated acyl chains. The outer leaflet's lipid acyl chains are more ordered and diffuse more slowly than those in the inner leaflet, probably resulting in greater stiffness in the outer membrane . This relative stiffness has critical implications for cellular processes, as membrane fusion and pore formation depend on membrane curvature. The rigidity of the outer leaflet protects cells against sharp negative membrane curvatures induced by viral fusion proteins or endogenous AMPs . This rigidity contrasts with the Gramnegative inner membrane , where the outer leaflet is rich in curvature-promoting PE . PE 3.4 Concluding remarks of the membrane section plays a crucial role in AMP-mediated pore formation , and this difference in curvature behavior may be key to designing AMPs with greater selectivity. A fundamental distinction between mammalian and bacterial membranes is the abundant presence of cholesterol in mammalian membranes, a molecule absent in bacterial membranes. Cholesterol imparts unique properties to eukaryotic membranes, including the formation of lateral domains often referred to as lipid rafts, which have critical biological functions . Cholesterol preferentially interacts with saturated lipids, promoting the formation of lipid rafts, particularly with sphingomyelin on the outer leaflet . These nano-or microdomains play significant roles in protein recruitment , and the differences of the biophysical characteristics between raft and non-raft domains probably affects AMP interactions . Interestingly, while increasing the energetic barrier for membrane permeation, cholesterol may in parallel keep the membrane highly elastic, a process termed diffusional softening . Cholesterol represents an attractive "anti-target" for the development of safe AMPs with improved selectivity between bacterial and human cell membranes. While the role of electrostatic interactions in AMP selectivity is well-established [331], cholesterol's contribution to membrane selectivity remains less clear. The various hypotheses surrounding cholesterol and AMP selectivity will be discussed in detail later in this review.