Genetic Assembly of Double‐Layered Fluorescent Protein Nanoparticles for Cancer Targeting and Imaging

Abstract

Hepatitis B virus capsid (HBVC), a self‐assembled protein nanoparticle comprised of 180 or 240 subunit proteins, is used as a cage for genetic encapsulation of fluorescent proteins (FPs). The self‐quenching of FPs is controlled by varying the spacing between FPs within the capsid structure. Double‐layered FP nanoparticle possessing cancer cell‐targeting capabilities is also produced by additionally attaching FPs and cancer cell receptor‐binding peptides (affibodies) to the outer surface of the capsid. The generically modified HBVC with double layers of mCardinal FPs and affibodies (mC‐DL‐HBVC) exhibit a high fluorescence intensity and a strong photostability, and is efficiently internalized by cancer cells and significantly stable against intracellular degradation. The mC‐DL‐HBVC effectively detects tumor in live mice with enhanced tumor targeting and imaging efficiency with far less accumulation in the liver, compared to a conventional fluorescent dye, Cy5.5. This suggests the great potential of mC‐DL‐HBVC as a promising contrast agent for in vivo tumor fluorescence imaging.

Near-Infrared Plasmonic Assemblies of Gold Nanoparticles with Multimodal Function for Targeted Cancer Theragnosis

“…Therefore, DMA-21mCG appears to be the best candidate for cancer theragnosis. Based on the previous literature 27 , 30 , the intracellular localization of DMA_21mCG can be determined from fluorescent cell images: punctate fluorescence patterns typically imply the confinement of fluorescent molecules within endosomal compartments such as lysosome, whereas smeared/diffuse fluorescent signals indicate the signaling molecules in cytosol. Figure 5 clearly shows the punctuate signals in tumor cells, suggesting that the intracellular DMAs are located in endosomal compartments.…”

“…The phothothermal conversion efficiencies (η pc ) of the DMA samples were estimated by comparing the measured cooling temperature profiles with the energy balance for the system 30 , 31 . where h , S , T max , T surr , Q in,surr , and I are heat transfer coefficient, surface area of the container, steady-state maximum temperature, temperature of the surrounding, heat dissipation due to the absorptoin of the light by the medium (a value of 25.7 mW has been reported for pure water) 30 , 31 , and laser power in the units of mW, respectively. The value of hS can be estimated using the equation where τ s , m w , and C w is system time constant, mass of the medium (water) (0.3 g), and heat capacity of water (4.2 J/g), respectively.…”

“…surface density, orientation, and activity of bio-ligands attached on AuNPs) are not well-controllable, which still remains problematic. In this study, these problems was resolved by genetic conjugation that enables highly uniform conjugation of correctly oriented bio-ligands without conformational alteration to protein template used for ordered assembly of AuNPs 30 .…”

Magnetic Particles: Their Applications from Sample Preparations to Biosensing Platforms

“…Fluorescent biosensing devices are based on changes caused by analytes in the chemical and physical properties of fluorophores, including fluorescence intensity, lifetime, and anisotropy, in connection with the process of charge transfer or power transmission process [52,53]. In addition, it has been known as an effective method for multiple and highly sensitive detections of biological targets in molecular and clinical diagnosis to monitor disease progression and drug/therapy method response to diagnose images and image-guided surgery [54][55][56][57]. The use of magnetic particles enables the high washing efficiency of the target separation step to rapidly remove the unwanted components, resulting in the enhancement of the limit of detection.…”

Peptide ligand‐mediated endocytosis of nanoparticles to cancer cells: Cell receptor‐binding‐ versus cell membrane‐penetrating peptides

“…The synthetic carriers such as liposomes and metal and polymer nanoparticles need to be chemically modified for the peptide ligand conjugation to their surface (Kango et al, ; Qie et al, ), and the chemically conjugated peptide ligands often suffer from the undesirable problems such as conformational denaturation, functional inactivation, and uncontrollable density and orientation on the synthetic carrier surface (Veronese, ). In recent studies, protein nanoparticles, that is, nano‐scale protein particles with a uniform size, shape, and surface topology, have been used as a biocompatible carrier of diverse biomolecules (viral and tumor‐specific antigens (Kim et al, ; Lee et al, ), siRNAs (Lee et al, ), and fluorescent proteins (Kim, Jo, Kwon, Won, & Lee, ), and gold nanoparticles (Kwon et al, , ; Kim, Lee, et al, ). The protein nanoparticles are synthesized through the self‐assembly of multiple protein subunits inside cells, and their surface is easily engineered to present peptides of interest through the genetic modification of each protein subunit (Lee et al, ; Park et al, ).…”