Dual-Surface-Modified Bacteriophage MS2 as an Ideal Scaffold for a Viral Capsid-Based Drug Delivery System

Abstract

With the development of covalent modification strategies for viral capsids comes the ability to convert them into modular carrier systems for drug molecules and imaging agents. With this overall goal in mind, we have used two orthogonal modification strategies to decorate the exterior surface of genome-free MS2 capsids with PEG chains, while installing 50-70 copies of a fluorescent dye inside as a drug cargo mimic. Despite the very high levels of modification, the capsids remained in the assembled state, as determined by TEM, size-exclusion chromatography, and dynamic light scattering analysis. The ability of the polymer coating to block the access of polyclonal antibodies to the capsid surface was probed using a sandwich ELISA, which indicated a 90% reduction in binding. Further experiments indicated that biotin groups placed at the distal ends of the polymer chains were still capable of binding to streptavidin, despite their proximity to the PEG layer. Finally, a modular strategy was developed for the attachment of small-molecule targeting groups to the polymer chains through an efficient oxime formation reaction. As a result of these studies, a robust and versatile new platform has emerged for the potential delivery of therapeutic cargo.

Antibody Conjugation Approach Enhances Breadth and Potency of Neutralization of Anti-HIV-1 Antibodies and CD4-IgG

“…Some minor modification was also observed in the heavy chain of Fab (see the supplemental material). This observation is in agreement with previous studies that demonstrated preferential diazene formation with the most accessible tyrosines (22,31,32). When trastuzumab that was not modified with FBDP was incubated with aplaviroc-oxyamine, no conjugation of aplaviroc-oxyamine occurred, as shown by MALDI-TOF mass spectrometry.…”

“…These studies revealed the many advantages of coupling active small molecules and peptides with antibodies. In contrast to bispecific-antibody approaches based on protein engineering, such as the dual-variable-domain (DVD)-Ig (21) or single-chain variable fragment (scFv)-Ig (22) fusion approaches, among others, laborious protein engineering is not required to endow a second specificity when the desired ligand is chemically coupled to the antibody. Furthermore, expression issues are bypassed, since development of a new cell line is not required.…”

The effects of time, temperature, and pH on the stability of PDU bacterial microcompartments

“…17 In addition to creating nanobioreactors, the Pdu MCP can also be adapted for use as protein cages in drug delivery. Polyhedral virus capsids have already shown promise in this field, [22][23][24][25] and the increased size of MCPs may permit additional cargo loading per particle. One of the barriers currently limiting progress towards practical application of bacterial MCPs is the lack of stability data.…”

MicroRNAs for Restenosis and Thrombosis After Vascular Injury

“…[135][136][137][138] Another promising class of nanoparticles useful for miRNAs delivery is represented by virus-like particles. 139 Viruslike particles are monodisperse particles, uniform in size and shape, consisting of the virus capsid devoid of genetic material. Various virus-like particles show different characteristics and conformations, depending on the virus of origin, 140 which allows optimal selection of the most appropriate virus-like particle for any use.…”