DNA‐Directed Patterning for Versatile Validation and Characterization of a Lipid‐Based Nanoparticle Model of SARS‐CoV‐2

Lipid‐based nanoparticles have been applied extensively in drug delivery and vaccine strategies and are finding diverse applications in the coronavirus disease 2019 (COVID‐19) pandemic—from vaccine‐component encapsulation to modeling the virus, itself. High‐throughput, highly flexible methods for characterization are of great benefit to the development of liposomes featuring surface proteins. DNA‐directed patterning is one such method that offers versatility in immobilizing and segregating lipid‐based nanoparticles for subsequent analysis. Here, oligonucleotides are selectively conjugated onto a glass substrate and then hybridized to complementary oligonucleotides tagged to liposomes, patterning them with great control and precision. The power of DNA‐directed patterning is demonstrated by characterizing a novel recapitulative lipid‐based nanoparticle model of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)—S–liposomes—that presents the SARS‐CoV‐2 spike (S) protein on its surface. Patterning a mixture of S–liposomes and liposomes that display the tetraspanin CD63 to discrete regions of a substrate shows that angiotensin‐converting enzyme 2 (ACE2) specifically binds to S–liposomes. Subsequent introduction of S–liposomes to ACE2‐expressing cells tests the biological function of S–liposomes and shows agreement with DNA‐directed patterning‐based assays. Finally, multiplexed patterning of S–liposomes verifies the performance of commercially available neutralizing antibodies against the two S variants. Overall, DNA‐directed patterning enables a wide variety of custom assays for the characterization of any lipid‐based nanoparticle.