Stability of Lipid Coatings on Nanoparticle-Decorated Surfaces

Engineering a biomimetic system for hepatocyte-specific RNAi treatment of non-alcoholic fatty liver disease

RNA interference (RNAi) presents great potential against intractable liver diseases. However, the establishment of specific, efficient, and safe delivery systems targeting hepatocytes remains a great challenge. Herein, we described a promising hepatocytes-targeting system through integrating triantennary N-acetylgalactosamine (GalNAc)-engineered cell membrane with biodegradable mesoporous silica nanoparticles, which efficiently and safely delivered siRNA to hepatocytes and silenced the target PCSK9 gene expression for the treatment of non-alcoholic fatty liver disease. Having optimized the GalNAc-engineering strategy, insertion orders, and cell membrane source, we obtained the best-performing GalNAc-formulations allowing strong hepatocyte-specific internalization with reduced Kupffer cell capture, resulting in robust gene silencing and less hepatotoxicity when compared with cationic lipid-based GalNAc-formulations. Consequently, a durable reduction of lipid accumulation and damage was achieved by systemic administering siRNAs targeting PCSK9 in high-fat diet-fed mice, accompanied by displaying desirable safety profiles. Taken together, this GalNAc-engineering biomimetics represented versatile, efficient, and safe carriers for the development of hepatocyte-specific gene therapeutics, and prevention of metabolic diseases. STATEMENT OF SIGNIFICANCE: Compared to MSN@LP-GN3 (MC3-LNP), MSN@CM-GN3 exhibited strong hepatocyte targeting and Kupffer cell escaping, as well as good biocompatibility for safe and efficient siRNA delivery. Furthermore, siPCSK9 delivered by MSN@CM-GN3 reduced both serum and liver LDL-C, TG, TC levels and lipid droplets in HFD-induced mice, resulting in better performance than MSN/siPCSK9@LP-GN3 in terms of lipid-lowering effect and safety profiles. These findings indicated promising advantages of our biomimetic GN3-based systems for hepatocyte-specific gene delivery in chronic liver diseases. Our work addressed the challenges associated with the lower targeting efficiency of cell membrane-mimetic drug delivery systems and the immunogenicity of traditional GalNAc delivery systems. In conclusion, this study provided an effective and versatile approach for efficient and safe gene editing using ligand-integrated biomimetic nanoplatforms.

Boosting the integration of cell membrane-nanomaterial hybrids via dextran-mediated dynamic dispersion system to capture bioactive compounds in natural products

Efficient integration is a prerequisite for the application of cell membrane-nanomaterial hybrids (CN hybrids) in bioanalysis, however, the poor dispersity of nanomaterials limits the development of this technology. Although the traditional hydrophilic modification method could improve the dispersity of nanomaterials, it would hinder the coating of the cell membrane, thus making it unsuitable for the integration of CN hybrids. Herein, a method has been proposed to improve the integration efficiency of CN hybrids from a different perspective, that is, establishing a dynamic dispersion system to enhance the interfacial interaction between cell membranes and nanomaterials. Specifically, magnetic graphene oxide (MGO) nanosheets were used as the model carrier and HepG2 cells were used as the source for membrane coating. The addition of the macromolecular stabilizer dextran to the integration process enhanced the dispersity of MGO and avoided the resistance to membrane coating caused by surface modification. Intriguingly, MGO in the dynamic dispersion system showed superior membrane coating ability as compared to hydrophilic modification methods, resulting in the more efficient integration of CN hybrids and greater sensitivity in capturing bioactive compounds from natural products. The proposed design principle provides a brand-new perspective for optimizing the behavior of CN hybrids and can improve the effectiveness of CN hybrids in bioanalytical applications.

A Facile Method to Coat Nanoparticles with Lipid Bilayer Membrane: Hybrid Silica Nanoparticles Disguised as Biomembrane Vesicles by Particle Penetration of Concentrated Lipid Layers

Natural membrane vesicles, including extracellular vesicles and enveloped viruses, participate in various events in vivo. To study and manipulate these events, biomembrane-coated nanoparticles inspired by natural membrane vesicles are developed. Herein, an efficient method is presented to prepare organic-inorganic hybrid materials in high yields that can accommodate various lipid compositions and particle sizes. To demonstrate this method, silica nanoparticles are passed through concentrated lipid layers prepared using density gradient centrifugation, followed by purification, to obtain lipid membrane-coated nanoparticles. Various lipids, including neutral, anionic, and cationic lipids, are used to prepare concentrated lipid layers. Single-particle analysis by imaging flow cytometry determines that silica nanoparticles are uniformly coated with a single lipid bilayer. Moreover, cellular uptake of silica nanoparticles is enhanced when covered with a lipid membrane containing cationic lipids. Finally, cell-free protein expression is applied to embed a membrane protein, namely the Spike protein of severe acute respiratory syndrome coronavirus 2, into the coating of the nanoparticles, with the correct orientation. Therefore, this method can be used to develop organic-inorganic hybrid nanomaterials with an inorganic core and a virus-like coating, serving as carriers for targeted delivery of cargos such as proteins, DNA, and drugs.

The effect of biomolecular corona on adsorption onto and desorption from a model lipid membrane

The current lack of insight into nanoparticle-cell membrane interactions hampers smart design strategies and thereby the development of effective nanodrugs. Quantitative and methodical approaches utilizing cell membrane models offer an opportunity to unravel particle-membrane interactions in a detailed manner under well controlled conditions. Here we use total internal reflection microscopy for real-time studies of the non-specific interactions between nanoparticles and a model cell membrane at 50 ms temporal resolution over a time course of several minutes. Maintaining a simple lipid bilayer system across conditions, adsorption and desorption were quantified as a function of biomolecular corona, particle size and fluid flow. The presence of a biomolecular corona reduced both the particle adsorption rate onto the membrane and the duration of adhesion, compared to pristine particle conditions. Particle size, on the other hand, was only observed to affect the adsorption rate. The introduction of flow reduced the number of adsorption events, but increased the residence time. Lastly, altering the composition of the membrane itself resulted in a decreased number of adsorption events onto negatively charged bilayers compared to neutral bilayers. Overall, a model membrane system offers a facile platform for real-time imaging of individual adsorption-desorption processes, revealing complex adsorption kinetics, governed by particle surface energy, size dependent interaction forces, flow and membrane composition.

Smart active-targeting of lipid-polymer hybrid nanoparticles for therapeutic applications: Recent advances and challenges

The advances in producing multifunctional lipid-polymer hybrid nanoparticles (LPHNs) by combining the biomimetic behavior of liposomes and architectural advantages of polymers have provided great opportunities for selective and efficient therapeutics delivery. The constructed LPHNs exhibit different therapeutic efficacies for special uses based on characteristics of different excipients. However, the high mechanical/structural stability of hybrid nano-systems could be viewed as both a negative property and a positive feature, where the concomitant release of drug molecules in a controllable manner is required. In addition, difficulties in scaling up the LPHNs production, due to involvement of several criteria, limit their application for biomedical fields, especially in monitoring, bioimaging, and drug delivery. To address these challenges bio-modifications have exhibited enormous potential to prepare reproducible LPHNs for site-specific therapeutics delivery, diagnostic and preventative applications. The ever-growing surface bio-functionality has provided continuous vitality to this biotechnology and has also posed desirable biosafety to nanoparticles (NPs). As a proof-of-concept, this manuscript provides a crucial review of coated lipid and polymer NPs displaying excellent surface functionality and architectural advantages. We also provide a description of structural classifications and production methodologies, as well as the biomedical possibilities and translational obstacles in the development of surface modified nanocarrier technology.

Accurate construction of cell membrane biomimetic graphene nanodecoys via purposeful surface engineering to improve screening efficiency of active components of traditional Chinese medicine

Biomimetic nanoengineering presents great potential in biomedical research by integrating cell membrane (CM) with functional nanoparticles. However, preparation of CM biomimetic nanomaterials for custom applications that can avoid the aggregation of nanocarriers while maintaining the biological activity of CM remains a challenge. Herein, a high-performance CM biomimetic graphene nanodecoy was fabricated via purposeful surface engineering, where polyethylene glycol (PEG) was used to modifying magnetic graphene oxide (MGO) to improve its stability in physiological solution, so as to improve the screening efficiency to active components of traditional Chinese medicine (TCM). With this strategy, the constructed PEGylated MGO (PMGO) could keep stable at least 10 days, thus improving the CM coating efficiency. Meanwhile, by taking advantage of the inherent ability of HeLa cell membrane (HM) to interact with specific ligands, HM-camouflaged PMGO showed satisfied adsorption capacity (116.2 mg/g) and selectivity. Finally, three potential active components, byakangelicol, imperatorin, and isoimperatorin, were screened from Angelica dahurica, whose potential antiproliferative activity were further validated by pharmacological studies. These results demonstrated that the purposeful surface engineering is a promising strategy for the design of efficient CM biomimetic nanomaterials, which will promote the development of active components screening in TCM.

Surface ligand rigidity modulates lipid raft affinity of ultra-small hydrophobic nanoparticles: insights from molecular dynamics simulations

Differential preferences between lipids and proteins drive the formation of dynamical nanoscale membrane domains (lipid rafts), which play key roles in the proper functioning of cells. On the other hand, due to the potent physicochemical properties of nanoparticles (NPs), they have been widely used in drug delivery, bio-imaging and regulating various essential biological processes of the cells. Hence, in this work, we aim to design ultra-small hydrophobic NPs with tunable raft affinity, which is supposed to partition into the hydrophobic region of lipid membranes and be able to regulate the dynamics of the lipid raft domains. A series of μs-scale coarse-grained molecular dynamics simulations and umbrella sampling free energy calculations were performed to investigate the role of surface ligand rigidity of ultra-small hydrophobicNPs in their raft affinity. Our results indicated that the preferred localization of NPs can be tuned by adjusting their surface ligand rigidity. Generally, rigid NPs tended to target the raft domain, while soft NPs preferred the interface of the raft and non-raft domains. The free energy analysis further indicated that the surface ligand rigidity of NPs can enhance their targeting to lipid raft domains. Besides, we found that these ultra-small NPs had no significant effects on the phase separation of the lipid membrane although they might cause some local interference to surrounding lipids. These results indicate that the targeting to the lipid raft domain can be achieved by the surface ligand rigidity of NPs, which provides helpful insights for further regulations of lipid raft-mediated biological processes.