ABSTRACT
Pharmaceutical drugs and vaccines require the use of material containers for protection, storage, and transportation. Glass and plastic materials are widely used for packaging, and a longstanding challenge in the field is the nonspecific adsorption of pharmaceutical drugs to container walls – the so-called "sticky containers, vanishing drugs” problem – that effectively reduces the active drug concentration and can cause drug denaturation. This challenge has been frequently discussed in the case of the anticancer drug, paclitaxel, and the ongoing coronavirus disease 2019 (COVID-19) pandemic has brought renewed attention to this material science challenge in light of the need to scale up COVID-19 vaccine production and to secure sufficient quantities of packaging containers. To reduce nonspecific adsorption on inner container walls, various strategies based on siliconization and thin polymer films have been explored, while it would be advantageous to develop mass-manufacturable, natural material solutions, especially ones involving pharmaceutical grade excipients. Inspired by how lipid nanoparticles have revolutionized the vaccine field, in this perspective, we discuss the prospects for developing lipid bilayer coatings to prevent nonspecific adsorption of pharmaceutical drugs and vaccines and how recent advances in lipid bilayer coating fabrication technologies are poised to accelerate progress in the field. We critically discuss recent examples of how lipid bilayer coatings can prevent nonspecific sticking of proteins and vaccines to relevant material surfaces and examine future translational prospects. © 2021 The Authors. VIEW published by Shanghai Fuji Technology Consulting Co., Ltd, authorized by Professional Community of Experimental Medicine, National Association of Health Industry and Enterprise Management (PCEM) and John Wiley & Sons Australia, Ltd.
ABSTRACT
The gp41 type I membrane protein is part of the trimeric Env complex forming the spikes at the HIV surface. By interacting with cellular receptors, the Env protein complex initiates the infectious cycle of HIV. After the first contact has been established Env disassembles by shedding gp120 while the remaining gp41 undergoes a number of conformational changes which drive fusion of the cellular and the viral membranes. Here we investigated the membrane interactions and oligomerization of the two gp41 heptad repeat domains NHR and CHR. While these are thought to form a six-helix bundle in the post-fusion state little is known about their structure and role during prior fusion events. When investigated in aqueous buffer by CD and fluorescence quenching techniques the formation of NHR/CHR hetero-oligomers is detected. An equilibrium of monomers and hetero-oligomers is also observed in membrane environments. Furthermore, the partitioning to POPC or POPC/POPG 3/1 vesicles of the two domains alone or in combination has been studied. The membrane interactions were further characterized by 15N solid-state NMR spectroscopy of uniaxially oriented samples which shows that the polypeptide helices are oriented parallel to the bilayer surface. The 31P solid-state NMR spectra of the same samples are indicative of considerable disordering of the membrane packing. The data support models where NHR and CHR insert in the viral and cellular membranes, respectively, where they exhibit an active role in the membrane fusion events.