Supramolecular Encapsulation of Small-Ultrared Fluorescent Proteins in Virus-Like Nanoparticles for Noninvasive In Vivo Imaging Agents

Abstract

Icosahedral virus-like particles (VLPs) derived from bacteriophages Qβ and PP7 encapsulating small-ultra red fluorescent protein (smURFP) were produced using a versatile supramolecualr capsid dissassemble-reassemble approach. The generated fluorescent VLPs display identical structural properties to their non-fluorescent analogs. Encapsulated smURFP shows indistinguishable photochemical properties to its unencapsulated counterpart, exhibits outstanding stability towards pH, and produces bright in vitro images following phagocytosis by macrophages. In vivo imaging allows biodistribution to be imaged at different time points. Ex vivo imaging of intravenously administered encapsulated smURFP reveleas localization in the liver and kidneys after 2 h blood circulation and substantial elimination after 16 h of imaging highlighting the potential application of these constructs as non-invasive in vivo imaging agents.

A self-labeling protein based on the small ultra-red fluorescent protein, smURFP

“…The smURFP-tag should find further use for the development of novel biosensors that utilize the smURFP-tag fluorescence with chemical and protein sensors 3 that recognize small molecules, peptides, and other biomolecules. smURFP-tag exogenous labelling of proteins with sortase-mediated attachment, 40 inclusion into virus particles, 41 and smURFP-tag nanoparticles 42 will allow for bioorthogonal, site-specific attachment of molecules without misfolding or optimization of reaction conditions for targeted or biosensor imaging in entire living animals.…”

Recent progress in targeted delivery vectors based on biomimetic nanoparticles

“…In previous studies, cell targeting with hybrid Qβ VNPs and engineered PP7 VNPs were applied to display severally epidermal growth factor (EGF) and peptides 239 , 240 . To realize noninvasive imaging, bacteriophages Qβ and PP7 were successfully hybridized to form a type of hybrid VNPs to load small ultra-red fluorescent protein (smURFP-hVNPs) via a versatile supramolecular disassembly–reassembly approach 241 . Compared with green fluorescent protein (GFP)-loaded analogs, smURFP-hVNPs were bestowed with more sensitive and specific pH response, contributing better imaging performance in the process of phagocytosis in RAW macrophages, and showing different tissue and organ localization.…”

Metal-Organic Framework Encapsulated Whole-Cell Vaccines Enhance Humoral Immunity against Bacterial Infection

“…80,[86][87] Formalin fixation induces chemical crosslinking of proteins to preserve their tertiary structure, resulting in bacterial cell death, whereas heat treatment kills bacteria through thermal stress. 88 Here, formalin-fixed CFT073 are referred to as CFTfixed and heat treated CFT073 are denoted as CFT-Heat. We first compared the time- show that intact CFT@ZIF (t 1/2 = 106.4 h) remained at the injection site 4 days longer than CFT-Fixed (t 1/2 = 11.1 h, Figure 2B).…”