Lipid nanocarriers absorb endogenous macromolecules (proteins, lipids, etc.) in blood, interstitial fluids or cytoplasm to form "protein coronas" in vivo. It is a challenging task to accurately resolve the structural and functional feature of the protein coronas. Centrifugation and size exclusion chromatography are common methods to separate protein coronas, but problems like low collection efficiency and impurity still exist.

To achieve accurate and efficient separation of protein coronas on PEG-encapsulated liposomes (sLip), we developed an affinity chromatography (AfC) technique based on anti-PEG single-stranded variable fragments (PEG-scFv) (Chu et al., Zhan*. Nano Lett, 2021). AfC elevates the collection efficiency by 43 times compared to centrifugation. In addition, this method avoids the contamination of endogenous vesicles and protein aggregates that occur during centrifugation, thereby retaining loosely bound proteins. Overall, our Afc technique provides a new method for in-depth interpretation of protein coronas.

On the basis of abovementioned breakthrough, we soon developed a brain-targeting delivery system by manipulating the protein corona’s function (Zhang et al.，Zhan*, Nat Commun, 2019). Specifically, we first modified liposomes with a short peptide(SP-SLIP). After entering the bloodstream, SP-SLIP is associated with brain-targeting apolipoproteins (ApoE\ApoJ\ApoA1) through interactions between the postganglionic domains of SP and apolipoproteins. Meanwhile, the function of absorbed plasma ApoE is preserved. This discovery paves a new way to promote clinical transformation of targeted drug delivery systems.

This customized delivery platform regulates key plasma proteins on the surface of lipid nanocarriers to achieve targeted tissue/cell drug delivery mediated by protein crowns. We will also use this platform to fuel further exploitation of mRNA-LNP targeted delivery.