Cloaking nanoparticles with protein corona shield for targeted drug delivery

Abstract

Targeted drug delivery using nanoparticles can minimize the side effects of conventional pharmaceutical agents and enhance their efficacy. However, translating nanoparticle-based agents into clinical applications still remains a challenge due to the difficulty in regulating interactions on the interfaces between nanoparticles and biological systems. Here, we present a targeting strategy for nanoparticles incorporated with a supramolecularly pre-coated recombinant fusion protein in which HER2-binding affibody combines with glutathione-S-transferase. Once thermodynamically stabilized in preferred orientations on the nanoparticles, the adsorbed fusion proteins as a corona minimize interactions with serum proteins to prevent the clearance of nanoparticles by macrophages, while ensuring systematic targeting functions in vitro and in vivo. This study provides insight into the use of the supramolecularly built protein corona shield as a targeting agent through regulating the interfaces between nanoparticles and biological systems.

Fig. 1

Protein corona shield nanoparticle (PCSN). a We introduce the protein corona shield (PCS) concept for an efficient target drug delivery system. Generally, nanoparticle drug carriers with a target ligand lose their targeting ability on being coated by blood proteins in a biological environment. However, the PCS system can inhibit blood protein adsorption to maintain the targeting ability and avoid unwanted clearance by the mononuclear phagocyte system. b Mass spectrometry analysis of the GST-HER2-Afb showed a mass of 36.3 kDa. c Zeta-potential analysis of mesoporous silica nanoparticle (MSN) (−23 mV), GSH-MSN (−39 mV), GST-HER2-Afb (−5.25 mV), and PCSN (−5.3 mV). d Size distribution plots of PCSN. e Images of cellular uptake of fluorescein 5 maleimide-modified GST-HER2-Afb by the target cell (SK-BR3) and the negative control (MCF-10A). f Transmission electron microscopic images of GSH-MSN and PCSN (scale bar represents 100 nm). All bar graphs were reported as means ± standard deviations (SDs) for three experimental replicates (n = 3)

Fig. 2

Proteomic study of surface protein corona. a GSH-MSN, PEG-MSN, and PCSN were treated with 55% serum for 1, 2, and 4 h, and the amount of serum protein attached to the surface was determined by SDS-PAGE. b Band intensity difference. c Classification of protein corona components characterized by quantitative LC-MS/MS. A total of 183 proteins were identified and the 78 most abundant proteins were used to make the heat map. d Proteins attached to each particle were classified by weight (kDa), category, and pI. e GSH-MSN, PCSN(R), PCSN(−), and PCSN were treated with 55% serum for 1 h and the amount of serum protein attached to the surface was determined by SDS-PAGE. All bar graphs were reported as means ± standard deviations (SDs) for three experimental replicates (n = 3)

Fig. 3

In vitro experiment and stealth effect of PCSN. a Schematic showing the avoidance of phagocytosis by a macrophage. b Confocal microscopy images of DiI-loaded PCSN and PEG-MSN, and free DiI incubated for 6 h in RAW264.7 cells (scale bar is 20 μm). c FACS analysis of PCSN and PEG-MSN incubated in RAW264.7 cells for 6 h. d Cell cytotoxicity assay of PCSN and free camptothecin (CPT) on RAW264.7 cells (48 h of incubation). e Schematic of the targeting ability of PCSN treated with 55% serum. Cellular uptake confocal microscopy images of f DiI-loaded PCSN to HEK293T cells (negative control) and to SK-BR3 (target cells). g Cellular uptake confocal microscopic images of camptothecin-loaded PCSN to SK-BR3 and cell cytotoxicity assay (scale bar is 10 μm). All bar graphs were reported as means ± standard deviations (SDs) for three experimental replicates (n = 3)

Fig. 4

Ex vivo and in vivo efficiency of PCSN. a, b Fluorescence images of organs and tumors 48 h after intravenous injection and biodistribution of injected formulations in animals with SK-BR3 tumor xenograft from fluorescence intensity analysis. In vivo antitumor effects in different treatment groups loaded with camptothecin (CPT) (1.5 mg/kg of mice) (scale bar is 2 cm). c Growth curve of tumor volume after intravenous injection with various groups of carriers until day 21 (n = 6 mice per group, mean ± 1 day [n = 6 mice per group, mean ± SD, statistical significance was calculated by one-way analysis of variance, *P < 0.05, **P < 0.01]