The role of surface chemistry in serum protein corona-mediated cellular delivery and gene silencing with lipid nanoparticles

Biofluid specific protein coronas affect lipid nanoparticle behavior in vitro

Lipid nanoparticles (LNPs) have successfully entered the clinic for the delivery of mRNA- and siRNA-based therapeutics, most recently as vaccines for COVID-19. Nevertheless, there is a lack of understanding regarding their in vivo behavior, in particular cell targeting. Part of this LNP tropism is based on the adherence of endogenous protein to the particle surface. This protein forms a so-called corona that can change, amongst other things, the circulation time, biodistribution and cellular uptake of these particles. The formation of this protein corona, in turn, is dependent on the nanoparticle properties (e.g., size, charge, surface chemistry and hydrophobicity) as well as the biological environment from which it is derived. With the potential of gene therapy to target virtually any disease, administration sites other than intravenous route are considered, resulting in tissue specific protein coronas. For neurological diseases, intracranial administration of LNPs results in a cerebral spinal fluid derived protein corona, possibly changing the properties of the lipid nanoparticle compared to intravenous administration. Here, the differences between plasma and CSF derived protein coronas on a clinically relevant LNP formulation were studied in vitro. Protein analysis showed that LNPs incubated in human CSF (C-LNPs) developed a protein corona composition that differed from that of LNPs incubated in plasma (P-LNPs). Lipoproteins as a whole, but in particular apolipoprotein E, represented a higher percentage of the total protein corona on C-LNPs than on P-LNPs. This resulted in improved cellular uptake of C-LNPs compared to P-LNPs, regardless of cell origin. Importantly, the higher LNP uptake did not directly translate into more efficient cargo delivery, underlining that further assessment of such mechanisms is necessary. These findings show that biofluid specific protein coronas alter LNP functionality, suggesting that the site of administration could affect LNP efficacy in vivo and needs to be considered during the development of the formulation.

Time-Resolved Inspection of Ionizable Lipid-Facilitated Lipid Nanoparticle Disintegration and Cargo Release at an Early Endosomal Membrane Mimic

Advances in lipid nanoparticle (LNP) design have contributed notably to the emergence of the current clinically approved mRNA-based vaccines and are of high relevance for delivering mRNA to combat diseases where therapeutic alternatives are sparse. LNP-assisted mRNA delivery utilizes ionizable lipid-mediated cargo translocation across the endosomal membrane driven by the acidification of the endosomal environment. However, this process occurs at a low efficiency, a few percent at the best. Utilizing surface-sensitive fluorescence microscopy with a single LNP and mRNA resolution, we have investigated pH-controlled interactions between individual LNPs and a planar anionic supported lipid bilayer (SLB) formed on nanoporous silica, mimicking the electrostatic conditions of the early endosomal membrane. For LNPs with an average diameter of 140 nm, fusion with the anionic SLB preferentially occurred when the pH was reduced from 6.6 to 6.0. Furthermore, there was a delay in the onset of LNP fusion after the pH drop, and upon fusion, a significant fraction (>70%) of mRNA was released into the acidic solution representing the endosomal lumen, while a fraction of mRNA remained bound to the SLB even after reversing the pH to neutral cytosolic conditions. Finally, a comparison of the fusion efficiency of two LNP formulations with different surface concentrations of gel-forming lipids correlated with differences in the protein translation efficiency previously observed in human primary cell transfection studies. Together, these findings emphasize the relevance of biophysical investigations of ionizable lipid-containing LNP-assisted mRNA delivery mechanisms while potentially also offering means to optimize the design of LNPs with enhanced endosomal escape capabilities.

Systemically targeting monocytic myloid-derrived suppressor cells using dendrimers and their cell-level biodistribution kinetics

The focus of nanoparticles in vivo trafficking has been mostly on their tissue-level biodistribution and clearance. Recent progress in the nanomedicine field suggests that the targeting of nanoparticles to immune cells can be used to modulate the immune response and enhance therapeutic delivery to the diseased tissue. In the presence of tumor lesions, monocytic-myeloid-derived suppressor cells (M-MDSCs) expand significantly in the bone marrow, egress into peripheral blood, and traffic to the solid tumor, where they help maintain an immuno-suppressive tumor microenvironment. In this study, we investigated the interaction between PAMAM dendrimers and M-MDSCs in two murine models of glioblastoma, by examining the cell-level biodistribution kinetics of the systemically injected dendrimers. We found that M-MDSCs in the tumor and lymphoid organs can efficiently endocytose hydroxyl dendrimers. Interestingly, the trafficking of M-MDSCs from the bone marrow to the tumor contributed to the deposition of hydroxyl dendrimers in the tumor. M-MDSCs showed different capacities of endocytosing dendrimers of different functionalities in vivo. This differential uptake was mediated by the unique serum proteins associated with each dendrimer surface functionality. The results of this study set up the framework for developing dendrimer-based immunotherapy to target M-MDSCs for cancer treatment.

Construction of GSH-responsive polyethyleneimine-based delivery vector for effective gene transfection

The rise of gene therapy has solved many diseases that cannot be effectively treated by conventional methods. Gene vectors is very important to protect and deliver the therapeutic genes to the target site. Polyethyleneimine (PEI) modified with mannitol could enhance the gene transfection efficiency reported by our group previously. In order to further control and improve the effective gene release to action site, disulfide bonds were introduced into mannitol-modified PEI to construct new non-viral gene vectors PeiSM. The degrees of mannitol linking with disulfide bonds were screened. Among them, moderate mannitol-modified PEI with disulfide bonds showed the best transfection efficiency, and significantly enhanced long-term systemic transgene expression for 72 hin vivoeven at a single dose administration, and could promote caveolae-mediated uptake through up-regulating the phosphorylation of caveolin-1 and increase the loaded gene release from the nanocomplexes in high glutathione intracellular environment. This functionalized gene delivery system can be used as an potential and safe non-viral nanovector for further gene therapy.

High-Throughput In Vivo Screening Identifies Differential Influences on mRNA Lipid Nanoparticle Immune Cell Delivery by Administration Route

Immune modulation through the intracellular delivery of nucleoside-modified mRNA to immune cells is an attractive approach for in vivo immunoengineering, with applications in infectious disease, cancer immunotherapy, and beyond. Lipid nanoparticles (LNPs) have come to the fore as a promising nucleic acid delivery platform, but LNP design criteria remain poorly defined, making the rate-limiting step for LNP discovery the screening process. In this study, we employed high-throughput in vivo LNP screening based on molecular barcoding to investigate the influence of LNP composition on immune tropism with applications in vaccines and systemic immunotherapies. Screening a large LNP library under both intramuscular (i.m.) and intravenous (i.v.) injection, we observed differential influences on LNP uptake by immune populations across the two administration routes, gleaning insight into LNP design criteria for in vivo immunoengineering. In validation studies, the lead LNP formulation for i.m. administration demonstrated substantial mRNA translation in the spleen and draining lymph nodes with a more favorable biodistribution profile than LNPs formulated with the clinical standard ionizable lipid DLin-MC3-DMA (MC3). The lead LNP formulations for i.v. administration displayed potent immune transfection in the spleen and peripheral blood, with one lead LNP demonstrating substantial transfection of splenic dendritic cells and another inducing substantial transfection of circulating monocytes. Altogether, the immunotropic LNPs identified by high-throughput in vivo screening demonstrated significant promise for both locally- and systemically-delivered mRNA and confirmed the value of the LNP design criteria gleaned from our screening process, which could potentially inform future endeavors in mRNA vaccine and immunotherapy applications.

Looking back, moving forward: protein corona of lipid nanoparticles

Lipid nanoparticles (LNPs) are commonly employed for drug delivery owing to their considerable drug-loading capacity, low toxicity, and excellent biocompatibility. Nevertheless, the formation of protein corona (PC) on their surfaces significantly influences the drug's in vivo fate (such as absorption, distribution, metabolism, and elimination) upon administration. PC denotes the phenomenon wherein one or multiple strata of proteins adhere to the external interface of nanoparticles (NPs) or microparticles within the biological milieu, encompassing ex vivo fluids (e.g., serum-containing culture media) and in vivo fluids (such as blood and tissue fluids). Hence, it is essential to claim the PC formation behaviors and mechanisms on the surface of LNPs. This overview provided a comprehensive examination of crucial aspects related to such issues, encompassing time evolution, controllability, and their subsequent impacts on LNPs. Classical studies of PC generation on the surface of LNPs were additionally integrated, and its decisive role in shaping the in vivo fate of LNPs was explored. The mechanisms underlying PC formation, including the adsorption theory and alteration theory, were introduced to delve into the formation process. Subsequently, the existing experimental outcomes were synthesized to offer insights into the research and application facets of PC, and it was concluded that the manipulation of PC held substantial promise in the realm of targeted delivery.

Surface property and in vitro toxicity effect of insoluble particles given by protein corona: Implication for PM cytotoxicity assessment

In vitro toxicological assessment helps explore key fractions of particulate matter (PM) in association with the toxic mechanism. Previous studies mainly discussed the toxicity effects of the water-soluble and organic-soluble fractions of PM. However, the toxicity of insoluble fractions is relatively poorly understood, and the adsorption of proteins is rarely considered. In this work, the formation of protein corona on the surface of insoluble particles during incubation in a culture medium was investigated. It was found that highly abundant proteins in fetal bovine serum were the main components of the protein corona. The adsorbed proteins increased the dispersion stability of insoluble particles. Meanwhile, the leaching concentrations of some metal elements (e.g., Cu, Zn, and Pb) from PM increased in the presence of proteins. The toxicity effects and potential mechanisms of the PM insoluble particle-protein corona complex on macrophage cells RAW264.7 were discussed. The results revealed that the PM insoluble particle-protein corona complex could influence the phagosome pathway in RAW264.7 cells. Thus, it promoted the intracellular reactive oxygen species generation and induced a greater degree of cell differentiation, significantly altering cell morphology. Consequently, this work sheds new light on the combination of insoluble particles and protein corona in terms of PM cytotoxicity assessment.

Engineering the protein corona: Strategies, effects, and future directions in nanoparticle therapeutics

Nanoparticles (NPs) serve as versatile delivery systems for anticancer, antibacterial, and antioxidant agents. The manipulation of protein-NP interactions within biological systems is crucial to the application of NPs in drug delivery and cancer nanotherapeutics. The protein corona (PC) that forms on the surface of NPs is the interface between biomacromolecules and NPs and significantly influences their pharmacokinetics and pharmacodynamics. Upon encountering proteins, NPs undergo surface alterations that facilitate their clearance from circulation by the mononuclear phagocytic system (MPS). PC behavior depends largely on the biological microenvironment and the physicochemical properties of the NPs. This review describes various strategies employed to engineer PC compositions on NP surfaces. The effects of NP characteristics such as size, shape, surface modification and protein precoating on PC performance were explored. In addition, this study addresses these challenges and guides the future directions of this evolving field.

Design of PD-L1-Targeted Lipid Nanoparticles to Turn on PTEN for Efficient Cancer Therapy

Lipid nanoparticles (LNPs) exhibit remarkable mRNA delivery efficiency, yet their majority accumulate in the liver or spleen after injection. Tissue-specific mRNA delivery can be achieved through modulating LNP properties, such as tuning PEGylation or varying lipid components systematically. In this paper, a streamlined method is used for incorporating tumor-targeting peptides into the LNPs; the programmed death ligand 1 (PD-L1) binding peptides are conjugated to PEGylated lipids via a copper-free click reaction, and directly incorporated into the LNP composition (Pep LNPs). Notably, Pep LNPs display robust interaction with PD-L1 proteins, which leads to the uptake of LNPs into PD-L1 overexpressing cancer cells both in vitro and in vivo. To evaluate anticancer immunotherapy mediated by restoring tumor suppressor, mRNA encoding phosphatase and tensin homolog (PTEN) is delivered via Pep LNPs to PTEN-deficient triple-negative breast cancers (TNBCs). Pep LNPs loaded with PTEN mRNA specifically promotes autophagy-mediated immunogenic cell death in 4T1 tumors, resulting in effective anticancer immune responses. This study highlights the potential of tumor-targeted LNPs for mRNA-based cancer therapy.

Impact of physicochemical properties on biological effects of lipid nanoparticles: Are they completely safe

Lipid nanoparticles (LNPs) are promising materials and human-use approved excipients, with manifold applications in biomedicine. Researchers have tended to focus on improving the pharmacological efficiency and organ targeting of LNPs, while paid relatively less attention to the negative aspects created by their specific physicochemical properties. Here, we discuss the impacts of LNPs' physicochemical properties (size, surface hydrophobicity, surface charge, surface modification and lipid composition) on the adsorption-transportation-distribution-clearance processes and bio-nano interactions. In addition, since there is a lack of review emphasizing on toxicological profiles of LNPs, this review outlined immunogenicity, inflammation, hemolytic toxicity, cytotoxicity and genotoxicity induced by LNPs and the underlying mechanisms, with the aim to understand the properties that underlie the biological effects of these materials. This provides a basic strategy that increased efficacy of medical application with minimized side-effects can be achieved by modulating the physicochemical properties of LNPs. Therefore, addressing the effects of physicochemical properties on toxicity induced by LNPs is critical for understanding their environmental and health risks and will help clear the way for LNPs-based drugs to eventually fulfill their promise as a highly effective therapeutic agents for diverse diseases in clinic.

Small-angle X-ray and neutron scattering applied to lipid-based nanoparticles: Recent advancements across different length scales

Lipid-based nanoparticles (LNPs), ranging from nanovesicles to non-lamellar assemblies, have gained significant attention in recent years, as versatile carriers for delivering drugs, vaccines, and nutrients. Small-angle scattering methods, employing X-rays (SAXS) or neutrons (SANS), represent unique tools to unveil structure, dynamics, and interactions of such particles on different length scales, spanning from the nano to the molecular scale. This review explores the state-of-the-art on scattering methods applied to unveil the structure of lipid-based nanoparticles and their interactions with drugs and bioactive molecules, to inform their rational design and formulation for medical applications. We will focus on complementary information accessible with X-rays or neutrons, ranging from insights on the structure and colloidal processes at a nanoscale level (SAXS) to details on the lipid organization and molecular interactions of LNPs (SANS). In addition, we will review new opportunities offered by Time-resolved (TR)-SAXS and -SANS for the investigation of dynamic processes involving LNPs. These span from real-time monitoring of LNPs structural evolution in response to endogenous or external stimuli (TR-SANS), to the investigation of the kinetics of lipid diffusion and exchange upon interaction with biomolecules (TR-SANS). Finally, we will spotlight novel combinations of SAXS and SANS with complementary on-line techniques, recently enabled at Large Scale Facilities for X-rays and neutrons. This emerging technology enables synchronized multi-method investigation, offering exciting opportunities for the simultaneous characterization of the structure and chemical or mechanical properties of LNPs.

Physiological Barriers and Strategies of Lipid-Based Nanoparticles for Nucleic Acid Drug Delivery

Lipid-based nanoparticles (LBNPs) are currently the most promising vehicles for nucleic acid drug (NAD) delivery. Although their clinical applications have achieved success, the NAD delivery efficiency and safety are still unsatisfactory, which are, to a large extent, due to the existence of multi-level physiological barriers in vivo. It is important to elucidate the interactions between these barriers and LBNPs, which will guide more rational design of efficient NAD vehicles with low adverse effects and facilitate broader applications of nucleic acid therapeutics. This review describes the obstacles and challenges of biological barriers to NAD delivery at systemic, organ, sub-organ, cellular, and subcellular levels. The strategies to overcome these barriers are comprehensively reviewed, mainly including physically/chemically engineering LBNPs and directly modifying physiological barriers by auxiliary treatments. Then the potentials and challenges for successful translation of these preclinical studies into the clinic are discussed. In the end, a forward look at the strategies on manipulating protein corona (PC) is addressed, which may pull off the trick of overcoming those physiological barriers and significantly improve the efficacy and safety of LBNP-based NADs delivery.

Targeting Strategies for Site-Specific mRNA Delivery

mRNA therapeutics hold great promise for disease treatment, yet a key challenge lies in achieving site-specific mRNA delivery to maximize therapeutic efficacy while minimizing off-target side effects. This viewpoint delves into multiple complementary targeting strategies to achieve precise site-specific mRNA delivery, covering topics of administration routes, passive targeting, and active targeting. It highlights the critical importance of rationally designed nanocarriers for obtaining desired therapeutic effects and accelerating the clinical translation of mRNA therapeutics.

Unveiling the challenges of engineered protein corona from the proteins' perspective

It is well known that protein corona affects the "biological identity" of nanoparticles (NPs), which has been seen as both a challenge and an opportunity. Approaches have moved from avoiding protein adsorption to trying to direct it, taking advantage of the formation of a protein corona to favorably modify the pharmacokinetic parameters of NPs. Although promising, the results obtained with engineered NPs still need to be completely understood. While much effort has been put into understanding how the surface of nanomaterials affects protein absorption, less is known about how proteins can affect corona formation due to their specific physicochemical properties. This review addresses this knowledge gap, examining key protein factors influencing corona formation, highlighting current challenges in studying protein-protein interactions, and discussing future perspectives in the field.

Nanocarrier-based gene delivery for immune cell engineering

Clinical advances in genetically modified immune cell therapies, such as chimeric antigen receptor T cell therapies, have raised hope for cancer treatment. The majority of these biotechnologies are based on viral methods for ex vivo genetic modification of the immune cells, while the non-viral methods are still in the developmental phase. Nanocarriers have been emerging as materials of choice for gene delivery to immune cells. This is due to their versatile physicochemical properties such as large surface area and size that can be optimized to overcome several practical barriers to successful gene delivery. The in vivo nanocarrier-based gene delivery can revolutionize cell-based cancer immunotherapies by replacing the current expensive autologous cell manufacturing with an off-the-shelf biomaterial-based platform. The aim of this research is to review current advances and strategies to overcome the challenges in nanoparticle-based gene delivery and their impact on the efficiency, safety, and specificity of the process. The main focus is on polymeric and lipid-based nanocarriers, and their recent preclinical applications for cancer immunotherapy.

Molecular interactions between gelatin-derived carbon quantum dots and Apo-myoglobin: Implications for carbon nanomaterial frameworks

Carbon nanomaterials (CNMs), including carbon quantum dots (CQDs), have found widespread use in biomedical research due to their low toxicity, chemical tunability, and tailored applications. Yet, there exists a gap in our understanding of the molecular interactions between biomacromolecules and these novel carbon-centered platforms. Using gelatin-derived CQDs as a model CNM, we have examined the impact of this exemplar nanomaterial on apo-myoglobin (apo-Mb), an oxygen-storage protein. Intrinsic fluorescence measurements revealed that the CQDs induced conformational changes in the tertiary structure of native, partially unfolded, and unfolded states of apo-Mb. Titration with CQDs also resulted in significant changes in the secondary structural elements in both native (holo) and apo-Mb, as evidenced by the circular dichroism (CD) analyses. These changes suggested a transition from isolated helices to coiled-coils during the loss of the helical structure of the apo-protein. Infra-red spectroscopic data further underscored the interactions between the CQDs and the amide backbone of apo-myoglobin. Importantly, the CQDs-driven structural perturbations resulted in compromised heme binding to apo-myoglobin and, therefore, potentially can attenuate oxygen storage and diffusion. However, a cytotoxicity assay demonstrated the continued viability of neuroblastoma cells exposed to these carbon nanomaterials. These results, for the first time, provide a molecular roadmap of the interplay between carbon-based nanomaterial frameworks and biomacromolecules.

Lipid nanoparticles containing labile PEG-lipids transfect primary human skin cells more efficiently in the presence of apoE

Nucleic acid-based therapeutics encapsulated into lipid nanoparticles (LNPs) can potentially target the root cause of genetic skin diseases. Although nanoparticles are considered impermeable to skin, research and clinical studies have shown that nanoparticles can penetrate into skin with reduced skin barrier function when administered topically. Studies have shown that epidermal keratinocytes express the low-density lipoprotein receptor (LDLR) that mediates endocytosis of apolipoprotein E (apoE)-associated nanoparticles and that dermal fibroblasts express mannose receptors. Here we prepared LNPs designed to exploit these different endocytic pathways for intracellular mRNA delivery to the two most abundant skin cell types, containing: (i) labile PEG-lipids (DMG-PEG2000) prone to dissociate and facilitate apoE-binding to LNPs, enabling apoE-LDLR mediated uptake in keratinocytes, (ii) non-labile PEG-lipids (DSPE-PEG2000) to impose stealth-like properties to LNPs to enable targeting of distant cells, and (iii) mannose-conjugated PEG-lipids (DSPE-PEG2000-Mannose) to target fibroblasts or potentially immune cells containing mannose receptors. All types of LNPs were prepared by vortex mixing and formed monodisperse (PDI ∼ 0.1) LNP samples with sizes of 130 nm (±25%) and high mRNA encapsulation efficiencies (≥90%). The LNP-mediated transfection potency in keratinocytes and fibroblasts was highest for LNPs containing labile PEG-lipids, with the addition of apoE greatly enhancing transfection via LDLR. Coating LNPs with mannose did not improve transfection, and stealth-like LNPs show limited to no transfection. Taken together, our studies suggest using labile PEG-lipids and co-administration of apoE when exploring LNPs for skin delivery.

Personalized Cancer Nanomedicine: Overcoming Biological Barriers for Intracellular Delivery of Biopharmaceuticals

The success of personalized medicine in oncology relies on using highly effective and precise therapeutic modalities such as small interfering RNA (siRNA) and monoclonal antibodies (mAbs). Unfortunately, the clinical exploitation of these biological drugs has encountered obstacles in overcoming intricate biological barriers. Drug delivery technologies represent a plausible strategy to overcome such barriers, ultimately facilitating the access to intracellular domains. Here, an overview of the current landscape on how nanotechnology has dealt with protein corona phenomena as a first and determinant biological barrier is presented. This continues with the analysis of strategies facilitating access to the tumor, along with conceivable methods for enhanced tumor penetration. As a final step, the cellular barriers that nanocarriers must confront in order for their biological cargo to reach their target are deeply analyzed. This review concludes with a critical analysis and future perspectives of the translational advances in personalized oncological nanomedicine.

Biological recognition and cellular trafficking of targeted RNA-lipid nanoparticles

Lipid nanoparticles (LNPs) have unlocked the potential of ribonucleic acid (RNA) therapeutics and vaccines. Production and large-scale manufacturing methods for RNA-LNPs have been established and rapidly accelerate. Despite this, basic research on LNPs is still required, due to their high assembly complexity and fairly new development, including research on lipid organization, transfection optimization, and in vivo behavior. Understanding fundamental aspects of LNPs that is, how lipid composition and physicochemical properties affect their biodistribution, cell recognition, and transfection, could propel their clinical development and facilitate overcoming current challenges. Herein, we review recent developments in the field of LNP technology and summarize the main findings focusing on nano-bio interactions.

Effect of lipid composition on RNA-Lipid nanoparticle properties and their sensitivity to thin-film freezing and drying

A library of 16 lipid nanoparticle (LNP) formulations with orthogonally varying lipid molar ratios was designed and synthesized, using polyadenylic acid [poly(A)] as a model for mRNA, to explore the effect of lipid composition in LNPs on (i) the initial size of the resultant LNPs and encapsulation efficiency of RNA and (ii) the sensitivity of the LNPs to various conditions including cold storage, freezing (slow vs. rapid) and thawing, and drying. Least Absolute Shrinkage and Selection Operator (LASSO) regression was employed to identify the optimal lipid molar ratios and interactions that favorably affect the physical properties of the LNPs and enhance their stability in various stress conditions. LNPs exhibited distinct responses under each stress condition, highlighting the effect of lipid molar ratios and lipid interactions on the LNP physical properties and stability. It was then demonstrated that it is feasible to use thin-film freeze-drying to convert poly(A)-LNPs from liquid dispersions to dry powders while maintaining the integrity of the LNPs. Importantly, the residual moisture content in LNP dry powders significantly affected the LNP integrity.Residual moisture content of ≤ 0.5% or > 3-3.5% w/w negatively affected the LNP size and/or RNA encapsulation efficiency, depending on the LNP composition. Finally, it was shown that the thin-film freeze-dried LNP powders have desirable aerosol properties for potential pulmonary delivery. It was concluded that Design of Experiments can be applied to identify mRNA-LNP formulations with the desired physical properties and stability profiles. Additionally, optimizing the residual moisture content in mRNA-LNP dry powders during (thin-film) freeze-drying is crucial to maintain the physical properties of the LNPs.

Size-Dependent In Vivo Transport of Nanoparticles: Implications for Delivery, Targeting, and Clearance

Understanding the in vivo transport of nanoparticles provides guidelines for designing nanomedicines with higher efficacy and fewer side effects. Among many factors, the size of nanoparticles plays a key role in controlling their in vivo transport behaviors due to the existence of various physiological size thresholds within the body and size-dependent nano-bio interactions. Encouraged by the evolving discoveries of nanoparticle-size-dependent biological effects, we believe that it is necessary to systematically summarize the size-scaling laws of nanoparticle transport in vivo. In this review, we summarized the size effect of nanoparticles on their in vivo transport along their journey in the body: begin with the administration of nanoparticles via different delivery routes, followed by the targeting of nanoparticles to intended tissues including tumors and other organs, and eventually clearance of nanoparticles through the liver or kidneys. We outlined the tools for investigating the in vivo transport of nanoparticles as well. Finally, we discussed how we may leverage the size-dependent transport to tackle some of the key challenges in nanomedicine translation and also raised important size-related questions that remain to be answered in the future.

Theranostic Lipid Nanoparticles for Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a common urological malignancy and represents a leading threat to healthcare. Recent years have seen a series of progresses in the early diagnosis and management of RCC. Theranostic lipid nanoparticles (LNPs) are increasingly becoming one of the focuses in this field, because of their suitability for tumor targeting and multimodal therapy. LNPs can be precisely fabricated with desirable chemical compositions and biomedical properties, which closely match the physiological characteristics and clinical needs of RCC. Herein, a comprehensive review of theranostic LNPs is presented, emphasizing the generic tool nature of LNPs in developing advanced micro-nano biomaterials. It begins with a brief overview of the compositions and formation mechanism of LNPs, followed with an introduction to kidney-targeting approaches, such as passive, active, and stimulus responsive targeting. With examples provided, a series of modification strategies for enhancing the tumor targeting and functionality of LNPs are discussed. Thereafter, research advances on applications of these LNPs for RCC including bioimaging, liquid biopsy, drug delivery, physical therapy, and gene therapy are summarized and discussed from an interdisciplinary perspective. The final part highlights the milestone achievements of translation medicine, current challenges as well as future development directions of LNPs for the diagnosis and treatment of RCC.

Protein Corona of Anionic Fluid-Phase Liposomes Compromises Their Integrity Rather than Uptake by Cells

Despite the undisputable role of the protein corona in the biointeractions of liposome drug carriers, the field suffers from a lack of knowledge regarding the patterns of protein deposition on lipid surfaces with different compositions. Here, we investigated the protein coronas formed on liposomes of basic compositions containing combinations of egg phosphatidylcholine (PC), palmitoyloleoyl phosphatidylglycerol (POPG), and cholesterol. Liposome-protein complexes isolated by size-exclusion chromatography were delipidated and analyzed using label-free LC-MS/MS. The addition of the anionic lipid and cholesterol both affected the relative protein abundances (and not the total bound proteins) in the coronas. Highly anionic liposomes, namely those containing 40% POPG, carried corona enriched with cationic proteins (apolipoprotein C1, beta-2-glycoprotein 1, and cathelicidins) and were the least stable in the calcein release assay. Cholesterol improved the liposome stability in the plasma. However, the differences in the corona compositions had little effect on the liposome uptake by endothelial (EA.hy926) and phagocytic cells in the culture (U937) or ex vivo (blood-derived monocytes and neutrophils). The findings emphasize that the effect of protein corona on the performance of the liposomes as drug carriers occurs through compromising particle stability rather than interfering with cellular uptake.

The use of RNA-based treatments in the field of cancer immunotherapy

Over the past several decades, mRNA vaccines have evolved from a theoretical concept to a clinical reality. These vaccines offer several advantages over traditional vaccine techniques, including their high potency, rapid development, low-cost manufacturing, and safe administration. However, until recently, concerns over the instability and inefficient distribution of mRNA in vivo have limited their utility. Fortunately, recent technological advancements have mostly resolved these concerns, resulting in the development of numerous mRNA vaccination platforms for infectious diseases and various types of cancer. These platforms have shown promising outcomes in both animal models and humans. This study highlights the potential of mRNA vaccines as a promising alternative approach to conventional vaccine techniques and cancer treatment. This review article aims to provide a thorough and detailed examination of mRNA vaccines, including their mechanisms of action and potential applications in cancer immunotherapy. Additionally, the article will analyze the current state of mRNA vaccine technology and highlight future directions for the development and implementation of this promising vaccine platform as a mainstream therapeutic option. The review will also discuss potential challenges and limitations of mRNA vaccines, such as their stability and in vivo distribution, and suggest ways to overcome these issues. By providing a comprehensive overview and critical analysis of mRNA vaccines, this review aims to contribute to the advancement of this innovative approach to cancer treatment.

Assessing Differential Particle Deformability under Microfluidic Flow Conditions

Assessing the mechanical behavior of nano- and micron-scale particles with complex shapes is fundamental in drug delivery. Although different techniques are available to quantify the bulk stiffness in static conditions, there is still uncertainty in assessing particle deformability in dynamic conditions. Here, a microfluidic chip is designed, engineered, and validated as a platform to assess the mechanical behavior of fluid-borne particles. Specifically, potassium hydroxide (KOH) wet etching was used to realize a channel incorporating a series of micropillars (filtering modules) with different geometries and openings, acting as microfilters in the direction of the flow. These filtering modules were designed with progressively decreasing openings, ranging in size from about 5 down to 1 μm. Discoidal polymeric nanoconstructs (DPNs), with a diameter of 5.5 μm and a height of 400 nm, were realized with different poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) ratios (PLGA/PEG), namely, 5:1 and 1:0, resulting in soft and rigid particles, respectively. Given the peculiar geometry of DPNs, the channel height was kept to 5 μm to limit particle tumbling or flipping along the flow. After thorough physicochemical and morphological characterization, DPNs were tested within the microfluidic chip to investigate their behavior under flow. As expected, most rigid DPNs were trapped in the first series of pillars, whereas soft DPNs were observed to cross multiple filtering modules and reach the micropillars with the smallest opening (1 μm). This experimental evidence was also supported by computational tools, where DPNs were modeled as a network of springs and beads immersed in a Newtonian fluid using the smoothed particle hydrodynamics (SPH) method. This preliminary study presents a combined experimental-computational framework to quantify, compare, and analyze the characteristics of particles having complex geometrical and mechanical attributes under flow conditions.

Effect of PEG Anchor and Serum on Lipid Nanoparticles: Development of a Nanoparticles Tracking Method

Polyethylene glycol (PEG) is used in Lipid Nanoparticles (LNPs) formulations to confer stealth properties and is traditionally anchored in membranes by a lipid moiety whose length significantly impacts the LNPs fate in vivo. C18 acyl chains are efficiently anchored in the membrane, while shorter C14 lipids are quickly desorbed and replaced by a protein corona responsible for the completely different fate of LNPs. In this context, a method to predict the biological behavior of LNPs depending on the lipid-PEG dissociation was developed using the Nanoparticle Tracking Analysis (NTA) method in serum. Two formulations of siRNA-containing LNPs were prepared including CSL3 or SM-102 lipids and were grafted with different lipids-PEG (C18, C14 lipids-PEG, and Ceramide-PEG). The impact of the lipid-PEG on the interactions between LNPs and serum components was demonstrated by monitoring the mean particle size and the concentration over time. In vitro, these formulations demonstrated low toxicity and efficient gene knockdown on tumor MDA-MB-231 cells, but serum was found to significantly impact the efficiency of C18-PEG-based LNPs, while it did not impact the efficiency of C14-PEG-based LNPs. The NTA method demonstrated the ability to discriminate between the behaviors of LNPs according to serum proteins' interactions. CSL3 lipid and Cer-PEG were confirmed to have promise for LNP formulation.

Passive, active and endogenous organ-targeted lipid and polymer nanoparticles for delivery of genetic drugs

Genetic drugs based on nucleic acid biomolecules are a rapidly emerging class of medicines that directly reprogramme the central dogma of biology to prevent and treat disease. However, multiple biological barriers normally impede the intracellular delivery of nucleic acids, necessitating the use of a delivery system. Lipid and polymer nanoparticles represent leading approaches for the clinical translation of genetic drugs. These systems circumnavigate biological barriers and facilitate the intracellular delivery of nucleic acids in the correct cells of the target organ using passive, active and endogenous targeting mechanisms. In this Review, we highlight the constituent materials of these advanced nanoparticles, their nucleic acid cargoes and how they journey through the body. We discuss targeting principles for liver delivery, as it is the organ most successfully targeted by intravenously administered nanoparticles to date, followed by the expansion of these concepts to extrahepatic (non-liver) delivery. Ultimately, this Review connects emerging materials and biological insights playing key roles in targeting specific organs and cells in vivo.

Protein corona: Friend or foe? Co-opting serum proteins for nanoparticle delivery

For systemically delivered nanoparticles to reach target tissues, they must first circulate long enough to reach the target and extravasate there. A challenge is that the particles end up engaging with serum proteins and undergo immune cell recognition and premature clearance. The serum protein binding, also known as protein corona formation, is difficult to prevent, even with artificial protection via "stealth" coating. Protein corona may be problematic as it can interfere with the interaction of targeting ligands with tissue-specific receptors and abrogate the so-called active targeting process, hence, the efficiency of drug delivery. However, recent studies show that serum protein binding to circulating nanoparticles may be actively exploited to enhance their downstream delivery. This review summarizes known issues of protein corona and traditional strategies to control the corona, such as avoiding or overriding its formation, as well as emerging efforts to enhance drug delivery to target organs via nanoparticles. It concludes with a discussion of prevailing challenges in exploiting protein corona for nanoparticle development.

Interaction Kinetics of Individual mRNA-Containing Lipid Nanoparticles with an Endosomal Membrane Mimic: Dependence on pH, Protein Corona Formation, and Lipoprotein Depletion

Lipid nanoparticles (LNPs) have emerged as potent carriers for mRNA delivery, but several challenges remain before this approach can offer broad clinical translation of mRNA therapeutics. To improve their efficacy, a better understanding is required regarding how LNPs are trapped and processed at the anionic endosomal membrane prior to mRNA release. We used surface-sensitive fluorescence microscopy with single LNP resolution to investigate the pH dependency of the binding kinetics of ionizable lipid-containing LNPs to a supported endosomal model membrane. A sharp increase of LNP binding was observed when the pH was lowered from 6 to 5, accompanied by stepwise large-scale LNP disintegration. For LNPs preincubated in serum, protein corona formation shifted the onset of LNP binding and subsequent disintegration to lower pH, an effect that was less pronounced for lipoprotein-depleted serum. The LNP binding to the endosomal membrane mimic was observed to eventually become severely limited by suppression of the driving force for the formation of multivalent bonds during LNP attachment or, more specifically, by charge neutralization of anionic lipids in the model membrane due to their association with cationic lipids from earlier attached LNPs upon their disintegration. Cell uptake experiments demonstrated marginal differences in LNP uptake in untreated and lipoprotein-depleted serum, whereas lipoprotein-depleted serum increased mRNA-controlled protein (eGFP) production substantially. This complies with model membrane data and suggests that protein corona formation on the surface of the LNPs influences the nature of the interaction between LNPs and endosomal membranes.

How Charge, Size and Protein Corona Modulate the Specific Activity of Nanostructured Lipid Carriers (NLC) against Helicobacter pylori

The major risk factor associated with the development of gastric cancer is chronic infection with Helicobacter pylori. The available treatments, based on a cocktail of antibiotics, fail in up to 40% of patients and disrupt their gut microbiota. The potential of blank nanostructured lipid carriers (NLC) for H. pylori eradication was previously demonstrated by us. However, the effect of NLC charge, size and protein corona on H. pylori-specific bactericidal activity herein studied was unknown at that time. All developed NLC formulations proved bactericidal against H. pylori. Although cationic NLC had 10-fold higher bactericidal activity than anionic NLC, they lacked specificity, since Lactobacillus acidophilus was also affected. Anionic NLC achieved complete clearance in both H. pylori morphologies (rod- and coccoid-shape) by inducing alterations in bacteria membranes and the cytoplasm, as visualized by transmission electron microscopy (TEM). The presence of an NLC protein corona, composed of 93% albumin, was confirmed by mass spectrometry. This protein corona delayed the bactericidal activity of anionic NLC against H. pylori and hindered NLC activity against Escherichia coli. Overall, these results sustain the use of NLC as a promising antibiotic-free strategy targeting H. pylori.

Surface charge influences protein corona, cell uptake and biological effects of carbon dots

Carbon dots are emerging nanoparticles (NPs) with tremendous applications, especially in the biomedical field. Herein is reported the first quantitative proteomic analysis of the protein corona formed on CDs with different surface charge properties. Four CDs were synthesized from citric acid and various amine group-containing passivation reagents, resulting in cationic NPs with increasing zeta (ζ)-potential and density of positive charges. After CD contact with serum, we show that protein corona identity is influenced by CD surface charge properties, which in turn impacts CD uptake and viability loss in macrophages. In particular, CDs with high ζ-potential (>+30 mV) and charge density (>2 μmol mg^-1) are the most highly internalized, and their cell uptake is strongly correlated with a corona enriched in vitronectin, fibulin, fetuin, adiponectin and alpha-glycoprotein. On the contrary, CDs with a lower ζ-potential (+11 mV) and charge density (0.01 μmol mg^-1) are poorly internalized, while having a corona with a very different protein signature characterized by a high abundance of apolipoproteins (APOA1, APOB and APOC), albumin and hemoglobin. These data illustrate how corona characterization may contribute to a better understanding of CD cellular fate and biological effects, and provide useful information for the development of CDs for biomedical applications.

The Yin and Yang of the protein corona on the delivery journey of nanoparticles

Nanoparticles-based drug delivery systems have attracted significant attention in biomedical fields because they can deliver loaded cargoes to the target site in a controlled manner. However, tremendous challenges must still be overcome to reach the expected targeting and therapeutic efficacy in vivo. These challenges mainly arise because the interaction between nanoparticles and biological systems is complex and dynamic and is influenced by the physicochemical properties of the nanoparticles and the heterogeneity of biological systems. Importantly, once the nanoparticles are injected into the blood, a protein corona will inevitably form on the surface. The protein corona creates a new biological identity which plays a vital role in mediating the bio-nano interaction and determining the ultimate results. Thus, it is essential to understand how the protein corona affects the delivery journey of nanoparticles in vivo and what we can do to exploit the protein corona for better delivery efficiency. In this review, we first summarize the fundamental impact of the protein corona on the delivery journey of nanoparticles. Next, we emphasize the strategies that have been developed for tailoring and exploiting the protein corona to improve the transportation behavior of nanoparticles in vivo. Finally, we highlight what we need to do as a next step towards better understanding and exploitation of the protein corona. We hope these insights into the "Yin and Yang" effect of the protein corona will have profound implications for understanding the role of the protein corona in a wide range of nanoparticles.

mRNA-LNP vaccines tuned for systemic immunization induce strong antitumor immunity by engaging splenic immune cells

mRNA vaccines have recently proven to be highly effective against SARS-CoV-2. Key to their success is the lipid-based nanoparticle (LNP), which enables efficient mRNA expression and endows the vaccine with adjuvant properties that drive potent antibody responses. Effective cancer vaccines require long-lived, qualitative CD8 T cell responses instead of antibody responses. Systemic vaccination appears to be the most effective route, but necessitates adaptation of LNP composition to deliver mRNA to antigen presenting cells. Using a design-of-experiments methodology, we tailored mRNA-LNP compositions to achieve high magnitude tumor-specific CD8 T cell responses within a single round of optimization. Optimized LNP compositions resulted in enhanced mRNA uptake by multiple splenic immune cell populations. Type I interferon and phagocytes were found essential for the T cell response. Surprisingly, we also discovered a yet unidentified role of B cells in stimulating the vaccine-elicited CD8 T cell response. Optimized LNPs displayed a similar, spleen-centered biodistribution profile in non-human primates and did not trigger histopathological changes in liver and spleen, warranting their further assessment in clinical studies. Taken together, our study clarifies the relationship between nanoparticle composition and their T cell stimulatory capacity and provides novel insights into the underlying mechanisms of effective mRNA-LNP based antitumor immunotherapy.

Protamine-Lipid-dsRNA Nanoparticles Improve RNAi Efficiency in the Fall Armyworm, Spodoptera frugiperda

Developing safe and effective double-stranded RNA (dsRNA) delivery systems remains a major challenge for gene silencing, especially in lepidopteran insects. This study evaluated the protamine sulfate (PS)/lipid/dsRNA nanoparticle (NP) delivery system for RNA interference (RNAi) in cells and larvae of the fall armyworm (FAW), Spodoptera frugiperda, a major worldwide pest. A highly efficient gene delivery formulation was prepared using a cationic biopolymer, PS, and a cationic lipid, Cellfectin (CF), complexed with dsRNA. The NPs were prepared by a two-step self-assembly method. The formation of NPs was revealed by dynamic light scattering and transmission electron microscopy. The formation of CF/dsRNA/PS NPs was spherical in shape and size, ranging from 20 to 100 nm with a positive charge (+23.3 mV). Interestingly, prepared CF/dsRNA/PS NPs could protect dsRNA (95%) from nuclease degradation and thus significantly improve the stability of dsRNA. Formulations prepared by combining EGFP DNA with CF/PS increased transfection efficiency in Sf9 cells compared to PS/EGFP and CF/EGFP NPs. Also, the PS/CF/dsRNA NPs enhanced the endosomal escape for the intracellular delivery of dsRNA. The gene knockdown efficiency was assessed in Sf9 Luciferase (Luc) stable cells after a 72 h incubation with CF/dsRNA/PS, PS/dsRNA, CF/dsRNA, or naked dsRNA. Knockdown of the Luc gene was detected in CF/dsRNA/PS (76%) and PS/dsRNA (42.4%) not CF/dsRNA (19.5%) and naked dsRNA (10.3%) in Sf9 Luc cells. Moreover, CF/dsIAP/PS (25 μg of dsRNA targeting the inhibitor of apoptosis, IAP, gene of FAW) NPs showed knockdown of the IAP gene (39.5%) and mortality (55%) in FAW larvae. These results highlight the potential application of PS/lipid/dsRNA NPs for RNA-mediated control of insect pests.

Changeable net charge on nanoparticles facilitates intratumor accumulation and penetration

The Enhanced Permeability and Retention (EPR) effect is a golden strategy for the nanoparticle (NP)-based targeting of solid tumors, and the surface property of NPs might be a determinant on their targeting efficiency. Poly(ethylene glycol) (PEG) is commonly used as a shell material; however, it has been pointed out that PEG-coated NPs may exhibit accumulation near tumor vasculature rather than having homogenous intratumor distribution. The PEG shell plays a pivotal role on prolonged blood circulation of NPs but potentially impairs the intratumor retention of NPs. In this study, we report on a shell material to enhance tumor-targeted delivery of NPs by maximizing the EPR effect: polyzwitterion based on ethylenediamine-based carboxybetaine [PGlu(DET-Car)], which shows the changeable net charge responding to surrounding pH. The net charge of PGlu(DET-Car), is neutral at physiological pH 7.4, allowing it to exhibit a stealth property during the blood circulation; however, it becomes cationic for tissue-interactive performance under tumorous acidic conditions owing to the stepwise protonation behavior of ethylenediamine. Indeed, the PGlu(DET-Car)-coated NPs (i.e., gold NPs in the present study) exhibited prolonged blood circulation and remarkably enhanced tumor accumulation and retention than PEG-coated NPs, achieving 32.1% of injected dose/g of tissue, which was 4.2 times larger relative to PEG-coated NPs. Interestingly, a considerable portion of PGlu(DET-Car)-coated NPs clearly penetrated into deeper tumor sites and realized the effective accumulation in hypoxic regions, probably because the cationic net charge of PGlu(DET-Car) is augmented in more acidic hypoxic regions. This study suggests that the changeable net charge on the NP surface in response to tumorous acidic conditions is a promising strategy for tumor-targeted delivery based on the EPR effect.

Nanoparticle personalized biomolecular corona: implications of pre-existing conditions for immunomodulation and cancer

Nanoparticles (NPs) have demonstrated great promise as immunotherapies for applications ranging from cancer, autoimmunity, and infectious disease. Upon encountering biological fluids, NPs rapidly adsorb biomolecules, forming the "biomolecular corona" (BC), and the altered character of NPs due to their newly acquired biological identity can impact their in vivo fate. Recently, it has been shown that the NP-BC is person-specific, and even minute differences in the biomolecule composition can give rise to altered immune recognition, cellular interactions, pharmacokinetics, and biodistribution. Given the current rise in the development of NP-based therapeutics, it is of utmost importance to better understand how pre-existing conditions, that result in the formation of a personalized BC, can be leveraged to aid in the prediction of the therapeutic outcomes of NPs. In this minireview, we will discuss the formation of the BC, implications of the BC for NP-biological interactions, and its clinical importance in the context of immunomodulation and cancer therapeutics.

Biosynthesis of ZnO Nanoparticles Using Capsicum chinense Fruit Extract and Their In Vitro Cytotoxicity and Antioxidant Assay

Green synthesis of nanoparticles (NPs) has garnered wide research interest due to inherent properties such as eco-friendliness, compatibility with substrates, and cost-effectiveness. Here, zinc oxide nanoparticles (ZnO-NPs) were successfully synthesized for the first time using Capsicum chinense fruit extract. The optical property of the green and conventionally synthesized ZnO-NPs was characterized by UV-vis spectrophotometer, which exhibited absorption peaks at 302 and 481 nm, respectively, and the morphology of the NPs was analyzed by transmission and scanning electron microscopies (TEM and SEM). The X-ray diffraction (XRD) studies showed that the hexagonal wurtzite phase was obtained, with high crystalline nature, while the electron dispersion X-ray study (EDX) revealed the purity of ZnO-NPs. The cytotoxicity assay of the biosynthesized and conventionally synthesized ZnO-NPs was evaluated using human embryonic kidney (HEK 293) and cervical carcinoma (HeLa) cell lines treated with various concentrations of the ZnO-NPs and they exhibited reasonable activity. Antioxidant activity of the ZnO-NPs was measured using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and the green ZnO-NPs exhibited higher activity compared to conventional ZnO-NPs. These findings proved that aqueous extracts of C. chinense fruit are effective for the biosynthesis of ZnO-NPs with anticancer and antioxidant potential.

Performance of nanoparticles for biomedical applications: The in vitro/in vivo discrepancy

Nanomedicine has a great potential to revolutionize the therapeutic landscape. However, up-to-date results obtained from in vitro experiments predict the in vivo performance of nanoparticles weakly or not at all. There is a need for in vitro experiments that better resemble the in vivo reality. As a result, animal experiments can be reduced, and potent in vivo candidates will not be missed. It is important to gain a deeper knowledge about nanoparticle characteristics in physiological environment. In this context, the protein corona plays a crucial role. Its formation process including driving forces, kinetics, and influencing factors has to be explored in more detail. There exist different methods for the investigation of the protein corona and its impact on physico-chemical and biological properties of nanoparticles, which are compiled and critically reflected in this review article. The obtained information about the protein corona can be exploited to optimize nanoparticles for in vivo application. Still the translation from in vitro to in vivo remains challenging. Functional in vitro screening under physiological conditions such as in full serum, in 3D multicellular spheroids/organoids, or under flow conditions is recommended. Innovative in vivo screening using barcoded nanoparticles can simultaneously test more than hundred samples regarding biodistribution and functional delivery within a single mouse.

Role of Ionic Strength in the Formation of Stable Supramolecular Nanoparticle-Protein Conjugates for Biosensing

Monolayer-protected gold nanoparticles (AuNPs) exhibit distinct physical and chemical properties depending on the nature of the ligand chemistry. A commonly employed NP monolayer comprises hydrophobic molecules linked to a shell of PEG and terminated with functional end group, which can be charged or neutral. Different layers of the ligand shell can also interact in different manners with proteins, expanding the range of possible applications of these inorganic nanoparticles. AuNP-fluorescent Green Fluorescent Protein (GFP) conjugates are gaining increasing attention in sensing applications. Experimentally, their stability is observed to be maintained at low ionic strength conditions, but not at physiologically relevant conditions of higher ionic strength, limiting their applications in the field of biosensors. While a significant amount of fundamental work has been done to quantify electrostatic interactions of colloidal nanoparticle at the nanoscale, a theoretical description of the ion distribution around AuNPs still remains relatively unexplored. We perform extensive atomistic simulations of two oppositely charged monolayer-protected AuNPs interacting with fluorescent supercharged GFPs co-engineered to have complementary charges. These simulations were run at different ionic strengths to disclose the role of the ionic environment on AuNP–GFP binding. The results highlight the capability of both AuNPs to intercalate ions and water molecules within the gold–sulfur inner shell and the different tendency of ligands to bend inward allowing the protein to bind not only with the terminal ligands but also the hydrophobic alkyl chains. Different binding stability is observed in the two investigated cases as a function of the ligand chemistry.

A higher dose of PEGylated gold nanoparticles reduces the accelerated blood clearance phenomenon effect and induces spleen B lymphocytes in albino mice

Polyethylene glycol (PEG) is a multifunctional polymer that has many uses in medical and biological applications. Recently, PEG has been mainly used in developing nanomaterial-based drug delivery systems (DDS). PEG is characterized by its high solubility, biological inertness, and ability to escape from immune cells (stealthiness) after systemic injection. The most challenging problem for PEGylated nanomaterials is their rapid elimination from the bloodstream after repeated doses of systemic injection, called accelerated blood clearance (ABC). Therefore, in this study, the effect of PEGylated nanomaterial dose concentration on ABC induction will be investigated using quantitative, histological, and immunohistochemical analyses. A higher dose concentration (2 mg/kg) of PEGylated gold nanoparticles (PEG-coated AuNPs) reduced the ABC phenomenon when intravenously injected into mice preinjected with the same dose. In contrast, a lower dose concentration (< 1 mg/kg) significantly induced the ABC phenomenon by the rapid elimination of the second dose of PEG-coated AuNPs from the bloodstream. To explain the relationship between the dose concentration (from PEG and AuNPs) and the induction of ABC, the biodistribution of PEG-coated AuNPs in liver and spleen [reticuloendothelial systems (RES)-rich organs] was investigated. The injected dose of PEG-coated AuNPs accumulated mainly in the hepatic Kupffer cells and hepatocytes. Similarly, spleen red pulp received a higher amount of the injected dose of PEG-coated AuNPs. However, the biodistriution profiles of PEG-coated AuNPs after the first and second dose for different dose concentrations varied in RES-rich organs. Additionally, the number of B lymphocytes, which have an important role in producing anti-PEG immunoglobulin (Ig)M, was affected by the repeated dose of PEG-coated AuNPs in the spleen. Therefore, for effective nanomaterial-based DDS development, dose optimization of PEG molecules that express PEGylated nanomaterials is important to reduce the ABC phenomenon effect. The ideal concentration of PEG molecules used to coat nanomaterials and the role of RES-rich organs must be determined to control the ABC phenomenon effect of PEGylated nanomaterials.

Change of Cell Toxicity of Food-Borne Nanoparticles after Forming Protein Coronas with Human Serum Albumin

Nanoparticles (NPs) can form protein coronas with plasma proteins after entering the biological environment due to their surface adsorption ability. In this study, the effects of protein coronas of roast squid food-borne nanoparticles (FNPs) with human serum albumin (HSA) on the HepG-2 and normal rat kidney (NRK) cells were investigated. The hydrodynamic diameters of the HSA and HSA-FNPs were 8 and 13 nm, respectively. The cytotoxicity and cell membrane damage of FNPs to HepG-2 cells increased with the increase of roasting temperature. The presence of 4.78 × 10^-3 mol/L FNPs increased the numbers of cellular necrosis and prolonged the G₂ phase of the cell cycle. The formation of protein coronas of squid FNPs mitigated the autophagy phenomenon by FNPs on HepG-2 cells. Moreover, protein coronas reduced the mitochondrial membrane potential in the HepG-2 and NRK cells and the production of reactive oxygen species caused by FNPs. The abnormal contents of oxidative stress indicators such as glutathione, superoxide dismutase, malondialdehyde, and catalase in HepG-2 and NRK cells induced by FNPs were alleviated due to the presence of HSA. These results suggested that the protein coronas formed by HSA on FNPs mitigated the cytotoxicity compared with the bare FNPs, thus providing insights into the interaction of squid FNPs with HSA.

Recent advances in lipid nanoparticles for delivery of nucleic acid, mRNA, and gene editing-based therapeutics

Lipid nanoparticles (LNPs) are becoming popular as a means of delivering therapeutics, including those based on nucleic acids and mRNA. The mRNA-based coronavirus disease 2019 vaccines are perfect examples to highlight the role played by drug delivery systems in advancing human health. The fundamentals of LNPs for the delivery of nucleic acid- and mRNA-based therapeutics, are well established. Thus, future research on LNPs will focus on addressing the following: expanding the scope of drug delivery to different constituents of the human body, expanding the number of diseases that can be targeted, and studying the change in the pharmacokinetics of LNPs under physiological and pathological conditions. This review article provides an overview of recent advances aimed at expanding the application of LNPs, focusing on the pharmacokinetics and advantages of LNPs. In addition, analytical techniques, library construction and screening, rational design, active targeting, and applicability to gene editing therapy have also been discussed.

Amniotic fluid stabilized lipid nanoparticles for in utero intra-amniotic mRNA delivery

Congenital disorders resulting in pathological protein deficiencies are most often treated postnatally with protein or enzyme replacement therapies. However, treatment of these disorders in utero before irreversible disease onset could significantly minimize disease burden, morbidity, and mortality. One possible strategy for the prenatal treatment of congenital disorders is in utero delivery of messenger RNA (mRNA). mRNA is a nucleic acid therapeutic that has previously been investigated as a platform for protein replacement therapies and gene editing technologies. While viral vectors have been explored to induce intracellular expression of mRNA, they are limited in their clinical application due to risks associated with immunogenicity and genomic integration. As an alternative to viral vectors, safe and efficient in utero mRNA delivery can be achieved using ionizable lipid nanoparticles (LNPs). While LNPs have demonstrated potent in vivo mRNA delivery to the liver following intravenous administration, intra-amniotic delivery has the potential to deliver mRNA to cells and tissues beyond those in the liver, such as in the skin, lung, and digestive tract. However, LNP stability in fetal amniotic fluid and how this stability affects mRNA delivery has not been previously investigated. Here, we engineered a library of LNPs using orthogonal design of experiments (DOE) to evaluate how LNP structure affects their stability in amniotic fluid ex utero and whether a lead candidate identified from these stability measurements enables intra-amniotic mRNA delivery in utero. We used a combination of techniques including dynamic light scattering (DLS), transmission electron microscopy (TEM), and chromatography followed by protein content quantification to screen LNP stability in amniotic fluids. These results identified multiple lead LNP formulations that are highly stable in amniotic fluids ranging from small animals to humans, including mouse, sheep, pig, and human amniotic fluid samples. We then demonstrate that stable LNPs from the ex utero screen in mouse amniotic fluid enabled potent mRNA delivery in primary fetal lung fibroblasts and in utero following intra-amniotic injection in a murine model. This exploration of ex utero stability in amniotic fluids demonstrates a means by which to identify novel LNP formulations for prenatal treatment of congenital disorders via in utero mRNA delivery.

Quantitative Analysis of Protein Corona on Precoated Protein Nanoparticles and Determined Nanoparticles with Ultralow Protein Corona and Efficient Targeting in Vivo

The protein corona on nanoparticles (NPs) is a critical problem that often screens the targeting molecules and becomes one of the key reasons for the lack of practical application in nanotherapy. It is critical to fully understand the mechanism of the nanoparticle-biological interactions to design the nanoparticle-based therapeutic agents. Some types of proteins can be precoated on the nanoparticles to avoid unwanted protein attachment; however, the ultralow level of protein corona is hard to achieve, and the relationship of the antifouling property of the precoated protein nanoparticles with protein conformation and protein-nanoparticle interaction energy has never been investigated. In this work, we provided the quantitative protein corona composition analysis on different precoated protein nanoparticles, and on the basis of the molecular simulation process, we found their antifouling property strongly depended on the interaction energy of the precoated protein-serum protein pair and the number of hydrogen bonds formed between them. Furthermore, it also depended on the nanoparticle-serum protein pair interaction energy and the protein conformation on the nanoparticle. The casein coated nanoparticle with the antifouling property was determined, and after aptamer conjugation and drug loading, they exhibited superior targeting and internalization behavior for photodynamic and photothermal therapy in vitro and in vivo. Our work adds to the understanding of the protein corona behavior of precoated protein nanoparticles, and the determined antifouling NP can potentially be used as a highly efficient nanodrug carrier.

New Applications of Lipid and Polymer-Based Nanoparticles for Nucleic Acids Delivery

Nucleic acids represent a promising lead for engineering the immune system. However, naked DNA, mRNA, siRNA, and other nucleic acids are prone to enzymatic degradation and face challenges crossing the cell membrane. Therefore, increasing research has been recently focused on developing novel delivery systems that are able to overcome these drawbacks. Particular attention has been drawn to designing lipid and polymer-based nanoparticles that protect nucleic acids and ensure their targeted delivery, controlled release, and enhanced cellular uptake. In this respect, this review aims to present the recent advances in the field, highlighting the possibility of using these nanosystems for therapeutic and prophylactic purposes towards combatting a broad range of infectious, chronic, and genetic disorders.

Spotlight on the protein corona of liposomes

Although an established drug delivery platform, liposomes have not fulfilled their true potential. In the body, interactions of liposomes are mediated by the layer of plasma proteins adsorbed on the surface, the protein corona. The review aims to collect the data of the last decade on liposome protein corona, tracing the path from interactions of individual proteins to the effects mediated by the protein corona in vivo. It offers a classification of the approaches to exploitation of the protein corona-rather than elimination thereof-based on the bilayer composition-corona composition-molecular interactions-biological performance framework. The multitude of factors that affect each level of this relationship urge to the widest implementation of bioinformatics tools to predict the most effective liposome compositions relying on the data on protein corona. Supplementing the picture with new pieces of accurately reported experimental data will contribute to the accuracy and efficiency of the predictions. STATEMENT OF SIGNIFICANCE: The review focuses on liposomes as an established nanomedicine platform and analyzes the available data on how the protein corona formed on liposome surface in biological fluids affects performance of the liposomes. The review offers a rigorous account of existing literature and critical analysis of methodology currently applied to the assessment of liposome-plasma protein interactions. It introduces a classification of the approaches to exploitation of the protein corona and tailoring liposome carriers to advance the field of nanoparticulate drug delivery systems for the benefit of patients.

Delivery of Oligonucleotide Therapeutics: Chemical Modifications, Lipid Nanoparticles, and Extracellular Vesicles

Oligonucleotides (ONs) comprise a rapidly growing class of therapeutics. In recent years, the list of FDA-approved ON therapies has rapidly expanded. ONs are small (15-30 bp) nucleotide-based therapeutics which are capable of targeting DNA and RNA as well as other biomolecules. ONs can be subdivided into several classes based on their chemical modifications and on the mechanisms of their target interactions. Historically, the largest hindrance to the widespread usage of ON therapeutics has been their inability to effectively internalize into cells and escape from endosomes to reach their molecular targets in the cytosol or nucleus. While cell uptake has been improved, "endosomal escape" remains a significant problem. There are a range of approaches to overcome this, and in this review, we focus on three: altering the chemical structure of the ONs, formulating synthetic, lipid-based nanoparticles to encapsulate the ONs, or biologically loading the ONs into extracellular vesicles. This review provides a background to the design and mode of action of existing FDA-approved ONs. It presents the most common ON classifications and chemical modifications from a fundamental scientific perspective and provides a roadmap of the cellular uptake pathways by which ONs are trafficked. Finally, this review delves into each of the above-mentioned approaches to ON delivery, highlighting the scientific principles behind each and covering recent advances.