Enhancing ovarian cancer treatment with maleimide-modified Pt(IV) prodrug nanoparticles

The limitations of platinum in ovarian cancer therapy, such as poor solubility and significant side effects, often lead to suboptimal therapeutic outcome and mortality. In this study, we have developed a novel approach utilizing biodegradable polymeric nanoparticles as a drug delivery system (NDDS), loaded with advanced platinum (IV) (Pt(IV)) prodrugs. A key feature of our approach is the enhancement of nanoparticles with maleimide, a modification hypothesized to significantly boost tumor tissue accumulation. When tested in mouse models of orthotopic and peritoneal metastasis ovarian cancer, these maleimide-modified nanoparticles are anticipated to show preferential accumulation in tumor tissues, enhancing therapeutic efficiency and minimizing systemic drug exposure. Our findings demonstrate that the maleimide-modified Pt(IV)-loaded NDDSs significantly reduce tumor burden in comparison to traditional cisplatin therapy, while simultaneously reducing adverse side effects. This leads to markedly improved survival rates in models of peritoneal metastasis ovarian cancer, offering a promising new direction in the treatment of this challenging disease.

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.

Exploring the Impact of Nanoparticle Stealth Coatings in Cancer Models: From PEGylation to Cell Membrane-Coating Nanotechnology

Nanotechnological platforms offer advantages over conventional therapeutic and diagnostic modalities. However, the efficient biointerfacing of nanomaterials for biomedical applications remains challenging. In recent years, nanoparticles (NPs) with different coatings have been developed to reduce nonspecific interactions, prolong circulation time, and improve therapeutic outcomes. This study aims to compare various NP coatings to enhance surface engineering for more effective nanomedicines. We prepared and characterized polystyrene NPs with different coatings of poly(ethylene glycol), bovine serum albumin, chitosan, and cell membranes from a human breast cancer cell line. The coating was found to affect the colloidal stability, adhesion, and elastic modulus of NPs. Protein corona formation and cellular uptake of NPs were also investigated, and a 3D tumor model was employed to provide a more realistic representation of the tumor microenvironment. The prepared NPs were found to reduce protein adsorption, and cell-membrane-coated NPs showed significantly higher cellular uptake. The secretion of proinflammatory cytokines in human monocytes after incubation with the prepared NPs was evaluated. Overall, the study demonstrates the importance of coatings in affecting the behavior and interaction of nanosystems with biological entities. The findings provide insight into bionano interactions and are important for the effective implementation of stealth surface engineering designs.

Physiological determinants and plausible '6R' roadmap for clinical success of nanomedicines

Despite the promising features and aggressive research, the success of nanoparticles in clinical trials is minimal. This manuscript discusses the complex biological barriers that impede the journey of nanoparticles to the target site and the approaches used to overcome them. The '6R' framework (right route, right target, right design, right patient, right combination and right technology) is proposed to improve the clinical translation of nanomedicines. Disease-driven approach contrary to the traditional formulation-driven approach is suggested. Data-driven methods can analyze the relationships between various diseases, patient pathophysiology and the physicochemical properties of different nanomedicines, aiding in the precise selection of the most appropriate treatment options. Further research is needed to evaluate and refine these approaches to develop nanomedicines for clinical success.

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.

Sticktight-inspired PEGylation for low-fouling coatings

Polyethylene glycol (PEG) has been widely used for modifying surfaces to reduce non-specific interactions with biomolecules, microorganisms, and cells. Herein, we report a sticktight-inspired PEGylation strategy to fabricate low-fouling coatings. The influence of PEG molecular architectures on the PEG density and biological adhesion were studied. Notably, an increase in the number of arms resulted in improved surface PEGylation and an improved antifouling ability against the adhesion of proteins, mammalian cells and bacteria. The molecular architecture-dependent PEGylation strategy is an attractive approach for developing advanced low-fouling coatings.

Recent advances in surface modification of micro- and nano-scale biomaterials with biological membranes and biomolecules

Surface modification of biomaterial can improve its biocompatibility and add new biofunctions, such as targeting specific tissues, communication with cells, and modulation of intracellular trafficking. Here, we summarize the use of various natural materials, namely, cell membrane, exosomes, proteins, peptides, lipids, fatty acids, and polysaccharides as coating materials on micron- and nano-sized particles and droplets with the functions imparted by coating with different materials. We discuss the applicability, operational parameters, and limitation of different coating techniques, from the more conventional approaches such as extrusion and sonication to the latest innovation seen on the microfluidics platform. Methods commonly used in the field to examine the coating, including its composition, physical dimension, stability, fluidity, permeability, and biological functions, are reviewed.

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.

Opsonized nanoparticles target and regulate macrophage polarization for osteoarthritis therapy: A trapping strategy

Osteoarthritis (OA) is a chronic disease caused by joint inflammation. Its occurrence and development depend on a continuous inflammation environment. The activated M1 macrophages play a critical role in the inflammatory response of OA. Regulating the pro-inflammatory M1 to anti-inflammatory M2 macrophages in the OA articular cavity could be a rational strategy for OA treatment. It has been acknowledged that activated macrophages could proactively capture opsonized nanoparticles in the bloodstream and then accumulate into the reticuloendothelial system (RES) organs. Based on this fact, a trapping strategy is proposed, which transforms a normal nanoparticle into an opsonized attractant to target and regulate macrophage polarization. In this study, the opsonized nanoparticle (IgG/Bb@BRPL) had several key features, including an immunoglobulin IgG (the opsonized layer), an anti-inflammatory agent berberine (Bb), and an oxidative stress-responsive bilirubin grafted polylysine biomaterial (BR-PLL) for drug loading (the inner nanocore). In vitro studies confirmed that IgG/Bb@BRPL prefer to be phagocytosed by M1 macrophage, not M0. And the internalized IgG/Bb@BRPL effectively promoted macrophage polarization toward the M2 phenotype and protected nearby chondrocytes. In vivo studies suggested that IgG/Bb@BRPL significantly enhanced therapeutic outcomes by suppressing inflammation and promoting cartilage repair while not prolonging the retention period compared to non-opsonized counterparts. This proof-of-concept study provided a novel opsonization trapping strategy for OA drug delivery and treatment.

Chemical and Biophysical Signatures of the Protein Corona in Nanomedicine

An inconvenient hurdle in the practice of nanomedicine is the protein corona, a spontaneous collection of biomolecular species by nanoparticles in living systems. The protein corona is dynamic in composition and may entail improved water suspendability and compromised delivery and targeting to the nanoparticles. How much of this nonspecific protein ensemble is determined by the chemistry of the nanoparticle core and its surface functionalization, and how much of this entity is dictated by the biological environments that vary spatiotemporally in vivo? How do we "live with" and exploit the protein corona without significantly sacrificing the efficacy of nanomedicines in diagnosing and curing human diseases? This article discusses the chemical and biophysical signatures of the protein corona and ponders challenges ahead for the field of nanomedicine.

Systematic Review of Cancer Targeting by Nanoparticles Revealed a Global Association between Accumulation in Tumors and Spleen

Active targeting of nanoparticles toward tumors is one of the most rapidly developing topics in nanomedicine. Typically, this strategy involves the addition of cancer-targeting biomolecules to nanoparticles, and studies on this topic have mainly focused on the localization of such formulations in tumors. Here, the analysis of the factors determining efficient nanoparticle targeting and therapy, various parameters such as types of targeting molecules, nanoparticle type, size, zeta potential, dose, and the circulation time are given. In addition, the important aspects such as how active targeting of nanoparticles alters biodistribution and how non-specific organ uptake influences tumor accumulation of the targeted nanoformulations are discussed. The analysis reveals that an increase in tumor accumulation of targeted nanoparticles is accompanied by a decrease in their uptake by the spleen. There is no association between targeting-induced changes of nanoparticle concentrations in tumors and other organs. The correlation between uptake in tumors and depletion in the spleen is significant for mice with intact immune systems in contrast to nude mice. Noticeably, modulation of splenic and tumor accumulation depends on the targeting molecules and nanoparticle type. The median survival increases with the targeting-induced nanoparticle accumulation in tumors; moreover, combinatorial targeting of nanoparticle drugs demonstrates higher treatment efficiencies. Results of the comprehensive analysis show optimal strategies to enhance the efficiency of actively targeted nanoparticle-based medicines.

The protein corona and its effects on nanoparticle-based drug delivery systems

In most cases, once nanoparticles (NPs) enter the blood, their surface is covered by biological molecules, especially proteins, forming a so-called protein corona (PC). As a result, what the cells of the body "see" is not the NPs as formulated by the chemists, but the PC. In this way, the PC can influence the effects of the NPs and even mask the desired effects of the NP components. While this can argue for trying to inhibit protein-nanomaterial interactions, encapsulating NPs in an endogenous PC may increase their clinical usefulness. In this review, we briefly introduce the concept of the PC, its formation and its effects on the behavior of NPs. We also discuss how to reduce the formation of PCs or exploit them to enhance NP functions. Studying the interactions between proteins and NPs will provide insights into their clinical activity in health and disease. STATEMENT OF SIGNIFICANCE: The formation of protein corona (PC) will affect the operation of nanoparticles (NPs) in vivo. Since there are many proteins in the blood, it is impossible to completely overcome the formation of PC. Therefore, the use of PCs to deliver drug is the best choice. De-opsonins adsorbed on NPs can reduce macrophage phagocytosis and cytotoxicity of NPs, and prolong their circulation in blood. Albumin, apolipoprotein and transferrin are typical de-opsonins. In present review, we mainly discuss how to optimize the delivery of nanoparticles through the formation of albumin corona, transferrin corona and apolipoprotein corona in vivo or in vitro.

The Fate of Nanoparticles In Vivo and the Strategy of Designing Stealth Nanoparticle for Drug Delivery

Nano-drug delivery systems (Nano-DDS) offer powerful advantages in drug delivery and targeted therapy for diseases. Compared to the traditional drug formulations, Nano-DDS can increase solubility, biocompatibility, and reduce off-targeted side effects of free drugs. However, they still have some disadvantages that pose a limitation in reaching their full potential in clinical use. Protein adsorption in blood, activation of the complement system, and subsequent sequestration by the mononuclear phagocyte system (MPS) consequently result in nanoparticles (NPs) to be rapidly cleared from circulation. Therefore, NPs have low drug delivery efficiency. So, it is important to develop stealth NPs for reducing bio-nano interaction. In this review, we first conclude the interaction between NPs and biological environments, such as blood proteins and MPS, and factors influencing each other. Next, we will summarize the new strategies to reduce NPs protein adsorption and uptake by the MPS based on current knowledge of the bio-nano interaction. Further directions will also be highlighted for the development of biomimetic stealth nano-delivery systems by combining targeted strategies for a better therapeutic effect.

An albumin-binding dimeric prodrug nanoparticle with long blood circulation and light-triggered drug release for chemo-photodynamic combination therapy against hypoxia-induced metastasis of lung cancer

Photodynamic therapy (PDT) has been widely used in cancer therapy, but its therapeutic effect is reduced by the aggravating hypoxic microenvironment via upregulating hypoxia-associated proteins and promoting tumor metastasis. To mitigate these issues, we designed an albumin-binding and light-triggered core-shell dimeric prodrug nanoparticle to inhibit hypoxia-induced tumor metastasis and enhance the PDT efficacy. The prodrug nanoparticles, Ce6&DHA-S-DHA@CMN NPs (CDC NPs), were prepared using a single thioether-linked dihydroartemisinin (DHA) dimer co-encapsulated with Chlorin e6 (Ce6) and stabilized by albumin-capturing maleimide- and hypoxia-sensitive 2-nitroimidazole-modified carboxymethyl chitosan (CMCTS-MAL&NI, CMN for short). Upon laser irradiation, Ce6 could generate reactive oxygen species (ROS), which not only exerted the effect of the PDT but also broke the ROS-sensitive single thioether bridge in the dimeric prodrug DHA-S-DHA, thus accelerating the disassembly of the nanoparticles. DHA-S-DHA served as both an ROS-responsive carrier for Ce6 and a chemotherapeutic drug, synergizing with PDT and inhibiting tumor metastasis by downregulating hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF). Polyethylene glycol (PEG) modification has been widely used to stabilize hydrophobic prodrug nanoparticles and prolong the circulation time, but the PEGylated nanoparticles always suffer from accelerated blood clearance (ABC), a phenomenon which restricts their application severely. In this study, PEG was replaced by an amphipathic micelle, CMN, which could specifically capture albumin in the blood, conferring the nanoparticles long circulation and no ABC phenomenon. Under the aggravating hypoxic condition during PDT, the conversion of 2-nitroimidazole groups to 2-aminoimidazole groups in CMN could destabilize the structure of the shell and accelerate drug release. Results showed that the novel CDC NPs exhibited unique advantages in chemo-photodynamic combination therapy, such as long systemic circulation, high tumor accumulation, light-triggered drug release, HIF-1α/VEGF downregulation, and anti-metastasis efficacy, which provided a new route to overcome the ABC phenomenon of the PEGylated prodrug nanoparticles and reverse the hypoxia-induced metastasis simultaneously.

Emerging nanotaxanes for cancer therapy

The clinical application of taxane (including paclitaxel, docetaxel, and cabazitaxel)-based formulations is significantly impeded by their off-target distribution, unsatisfactory release, and acquired resistance/metastasis. Recent decades have witnessed a dramatic progress in the development of high-efficiency, low-toxicity nanotaxanes via the use of novel biomaterials and nanoparticulate drug delivery systems (nano-DDSs). Thus, in this review, the achievements of nanotaxanes-targeted delivery and stimuli-responsive nano-DDSs-in preclinical or clinical trials have been outlined. Then, emerging nanotherapeutics against tumor resistance and metastasis have been overviewed, with a particular emphasis on synergistic therapy strategies (e.g., combination with surgery, chemotherapy, radiotherapy, biotherapy, immunotherapy, gas therapy, phototherapy, and multitherapy). Finally, the latest oral nanotaxanes have been briefly discussed.

In vivo Protein Corona Formation: Characterizations, Effects on Engineered Nanoparticles' Biobehaviors, and Applications

Understanding the basic interactions between engineered nanoparticles (ENPs) and biological systems is essential for evaluating ENPs’ safety and developing better nanomedicine. Profound interactions between ENPs and biomolecules such as proteins are inevitable to occur when ENPs are administered or exposed to biological systems, for example, through intravenous injection, oral, or respiration. As a key component of these interactions, protein corona (PC) is immediately formed surrounding the outlayer of ENPs. PC formation is crucial because it gives ENPs a new biological identity by altering not only the physiochemical properties, but also the biobehaviors of ENPs. In the past two decades, most investigations about PC formation were carried out with in vitro systems which could not represent the true events occurring within in vivo systems. Most recently, studies of in vivo PC formation were reported, and it was found that the protein compositions and structures were very different from those formed in vitro. Herein, we provide an in-time review of the recent investigations of this in vivo PC formation of ENPs. In this review, commonly used characterization methods and compositions of in vivo PC are summarized firstly. Next, we highlight the impacts of the in vivo PC formation on absorption, blood circulation, biodistribution, metabolism, and toxicity of administered ENPs. We also introduce the applications of modulating in vivo PC formation in nanomedicine. We further discuss the challenges and future perspectives.

Stabilized albumin coatings on engineered xenografts for attenuation of acute immune and inflammatory responses

Xenogeneic grafts are promising candidates for transplantation therapy due to their easily accessible sources. Nevertheless, the immune and inflammatory responses induced by xenografts need to be addressed for clinical use. A novel and facile method was introduced for the attenuation of immune and inflammatory responses by extending the immune evasion potential of albumin to the tissue engineering field and coating albumin, which could passivate biomaterial surfaces, onto xenografts. Albumin was first modified by dopamine to enhance its adhesion on graft surfaces. Porcine chondrocytes derived living hyaline cartilage graft (LhCG) and decellularized LhCG (dLhCG) were applied as xenograft models implanted in the omentum of rats. Both LhCG which contained porcine chondrocytes as well as secreted ECM and dLhCG which was mainly composed of the porcine source ECM showed alleviated immune and inflammatory responses after being coated with albumin at cell, protein and gene levels, respectively. Significantly less inflammatory cells including neutrophils, macrophages and lymphocytes were recruited according to pathological analysis and immunohistochemistry staining with lower gene expression encoding inflammation-related cytokines including MCP-1, IL-6 and IL-1β after employing LhCG and dLhCG with albumin passivation coating.

In vivo protein corona on nanoparticles: does the control of all material parameters orient the biological behavior?

Nanomaterials have a huge potential in research fields from nanomedicine to medical devices. However, surface modifications of nanoparticles (NPs) and thus of their physicochemical properties failed to predict their biological behavior. This requires investigating the "missing link" at the nano-bio interface. The protein corona (PC), the set of proteins binding to the NPs surface, plays a critical role in particle recognition by the innate immune system. Still, in vitro incubation offers a limited understanding of biological interactions and fails to explain the in vivo fate. To date, several reports explained the impact of PC in vitro but its applications in the clinical field have been very limited. Furthermore, PC is often considered as a biological barrier reducing the targeting efficiency of nano vehicles. But the protein binding can actually be controlled by altering PC both in vitro and in vivo. Analyzing PC in vivo could accordingly provide a deep understanding of its biological effect and speed up the transfer to clinical applications. This review demonstrates the need for clarifications on the effect of PC in vivo and the control of its behavior by changing its physicochemical properties. It unfolds the recent in vivo developments to understand mechanisms and challenges at the nano-bio interface. Finally, it reports recent advances in the in vivo PC to overcome and control the limitations of the in vitro PC by employing PC as a boosting resource to prolong the NPs half-life, to improve their formulations and thereby to increase its use for biomedical applications.

Virus-mimetic systems for cancer diagnosis and therapy

Over past decades, various strategies have been developed to enhance the delivery efficiency of therapeutics and imaging agents to tumor tissues. However, the therapeutic outcome of tumors to date have not been significantly improved, which can be partly attributed to the weak targeting ability, fast elimination, and low stability of conventional delivery systems. Viruses are the most efficient agents for gene transfer, serving as a valuable source of inspiration for designing nanoparticle-based delivery systems. Based on the properties of viruses, including well-defined geometry, precise composition, easy modification, stable construction, and specific infection, researchers attempt to design biocompatible delivery vectors by mimicking virus assembly and using the vector system to selectively concentrate drugs or imaging probes in tumors with mitigated toxicity and improved efficacy. In this review, we introduce common viruses features and provide an overview of various virus-mimetic strategies for cancer therapy and diagnosis. The challenges faced by virus-mimetic systems are also discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Drug discovery and formulation development for acute pancreatitis

Acute pancreatitis is a sudden inflammation and only last for a short time, but might lead to a life-threatening emergency. Traditional drug therapy is an essential supportive method for acute pancreatitis treatment, yet, failed to achieve satisfactory therapeutic outcomes. To date, it is still challenging to develop therapeutic medicine to redress the intricate microenvironment promptly in the inflamed pancreas, and more importantly, avoid multi-organ failure. The understanding of the acute pancreatitis, including the causes, mechanism, and severity judgment, could help the scientists bring up more effective intervention and treatment strategies. New formulation approaches have been investigated to precisely deliver therapeutics to inflammatory lesions in the pancreas, and some even could directly attenuate the pancreatic damages. In this review, we will briefly introduce the involved pathogenesis and underlying mechanisms of acute pancreatitis, as well as the traditional Chinese medicine and the new drug option. Most of all, we will summarize the drug delivery strategies to reduce inflammation and potentially prevent the further development of pancreatitis, with an emphasis on the bifunctional nanoparticles that act as both drug delivery carriers and therapeutics.

Silk Fibroin-Modified Disulfiram/Zinc Oxide Nanocomposites for pH Triggered Release of Zn2+ and Synergistic Antitumor Efficacy

Disulfiram (DSF) is an FDA-approved anti-alcoholic drug that has recently proven to be effective in cancer treatment. However, the short half-life in the bloodstream and the metal ion-dependent antitumor activity significantly limited the further application of DSF in the clinical field. To this end, we constructed a silk fibroin modified disulfiram/zinc oxide nanocomposites (SF/DSF@ZnO) to solubilize and stabilize DSF, and, more importantly, achieve pH triggered Zn²⁺ release and subsequent synergistic antitumor activity. The prepared SF/DSF@ZnO nanocomposites were spherical and had a high drug loading. Triggered by the lysosomal pH, SF/DSF@ZnO could induce the rapid release of Zn²⁺ under the acidic conditions and caused nanoparticulate disassembly along with DSF release. In vitro experiments showed that cytotoxicity of DSF could be enhanced by the presence of Zn²⁺, and further amplified when encapsulated into SF/DSF@ZnO nanocomposites. It was confirmed that the significantly amplified cytotoxicity of SF/DSF@ZnO was resulted from pH-triggered Zn²⁺ release, inhibited cell migration, and increased ROS production. In vivo study showed that SF/DSF@ZnO nanocomposites significantly increased the tumor accumulation and prolonged the retention time. In vivo antitumor experiments in the xenograft model showed that SF/DSF@ZnO exerted the highest tumor-inhibition rate among all the drug treatments. Therefore, this exquisite study established silk fibroin-modified disulfiram/zinc oxide nanocomposites, SF/DSF@ZnO, where ZnO not only acted as a delivery carrier but also served as a metal ion reservoir to achieve synergistic antitumor efficacy. The established DSF nanoformulation displayed excellent therapeutic potential in future cancer treatment.

Recent Advances in Understanding the Protein Corona of Nanoparticles and in the Formulation of "Stealthy" Nanomaterials

In the last decades, the staggering progress in nanotechnology brought around a wide and heterogeneous range of nanoparticle-based platforms for the diagnosis and treatment of many diseases. Most of these systems are designed to be administered intravenously. This administration route allows the nanoparticles (NPs) to widely distribute in the body and reach deep organs without invasive techniques. When these nanovectors encounter the biological environment of systemic circulation, a dynamic interplay occurs between the circulating proteins and the NPs, themselves. The set of proteins that bind to the NP surface is referred to as the protein corona (PC). PC has a critical role in making the particles easily recognized by the innate immune system, causing their quick clearance by phagocytic cells located in organs such as the lungs, liver, and spleen. For the same reason, PC defines the immunogenicity of NPs by priming the immune response to them and, ultimately, their immunological toxicity. Furthermore, the protein corona can cause the physical destabilization and agglomeration of particles. These problems induced to consider the PC only as a biological barrier to overcome in order to achieve efficient NP-based targeting. This review will discuss the latest advances in the characterization of PC, development of stealthy NP formulations, as well as the manipulation and employment of PC as an alternative resource for prolonging NP half-life, as well as its use in diagnostic applications.

Lipid-based Vehicles for siRNA Delivery in Biomedical Field

BACKGROUND

Genetic drugs have aroused much attention in the past twenty years. RNA interference (RNAi) offers novel insights into discovering potential gene functions and therapies targeting genetic diseases. Small interference RNA (siRNA), typically 21-23 nucleotides in length, can specifically degrade complementary mRNA. However, targeted delivery and controlled release of siRNA remain a great challenge.

METHODS

Different types of lipid-based delivery vehicles have been synthesized, such as liposomes, lipidoids, micelles, lipoplexes and lipid nanoparticles. These carriers commonly have a core-shell structure. For active targeting, ligands may be conjugated to the surface of lipid particles.

RESULTS

Lipid-based drug delivery vehicles can be utilized in anti-viral or anti-tumor therapies. They can also be used to tackle genetic diseases or discover novel druggable genes.

CONCLUSION

In this review, the structures of lipid-based vehicles and possible surface modifications are described, and applications of delivery vehicles in biomedical field are discussed.

Emerging well-tailored nanoparticulate delivery system based on in situ regulation of the protein corona

The protein corona significantly changes the nanoparticle (NP) identity both physicochemically and biologically, and in situ regulation of specific plasma protein adsorption on NP surfaces has emerged as a promising strategy for disease-targeting therapy. In the past decade, great progress in protein corona regulation has been achieved via surface chemistry-based nanomedicine development. This review first outlines the latest advances in bio-nano interactions, with special attention to factors that influence the protein corona, including NP physicochemical properties, the biological environment and the duration time. Second, NP surface chemistry strategies designed to inhibit and regulate protein corona formation are highlighted, with special emphasis on albumin, transferrin, apolipoprotein (apo) E, vascular endothelial growth factor (VEGF) and retinol binding protein 4 (RBP4). Finally, the current techniques used to characterize the protein corona are briefly discussed.

In situ apolipoprotein E-enriched corona guides dihydroartemisinin-decorating nanoparticles towards LDLr-mediated tumor-homing chemotherapy

The therapeutic efficiency of active targeting nanoparticulate drug delivery systems (nano-DDS) is highly compromised by the plasma proteins adsorption on nanoparticles (NPs) surface, which significantly hinders cell membrane receptors to recognize the designed ligands, and provokes the off-target toxicity and rapid clearance of NPs in vivo. Herein, we report a novel dihydroartemisinin (DHA)-decorating nano-DDS that in situ specifically recruits endogenous apolipoprotein E (apoE) on the NPs surface. The apoE-anchored corona is able to prolong PLGA-PEG2000-DHA (PPD) NPs circulation capability in blood, facilitate NPs accumulating in tumor cells by the passive enhanced permeability and retention (EPR) effect and low-density lipoprotein receptor (LDLr)-mediated target transport, and ultimately improve the in vivo antitumor activity. Our findings demonstrate that the strategy of in situ regulated apoE-enriched corona ensures NPs an efficient LDLr-mediated tumor-homing chemotherapy.

Link between Low-Fouling and Stealth: A Whole Blood Biomolecular Corona and Cellular Association Analysis on Nanoengineered Particles

Upon exposure to human blood, nanoengineered particles interact with a multitude of plasma components, resulting in the formation of a biomolecular corona. This corona modulates downstream biological responses, including recognition by and association with human immune cells. Considerable research effort has been directed toward the design of materials that can demonstrate a low affinity for various proteins (low-fouling materials) and materials that can exhibit low association with human immune cells (stealth materials). An implicit assumption common to bio-nano research is that nanoengineered particles that are low-fouling will also exhibit stealth. Herein, we investigated the link between the low-fouling properties of a particle and its propensity for stealth in whole human blood. High-fouling mesoporous silica (MS) particles and low-fouling zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) particles were synthesized, and their interaction with blood components was assessed before and after precoating with serum albumin, immunoglobulin G, or complement protein C1q. We performed an in-depth proteomics characterization of the biomolecular corona that both identifies specific proteins and measures their relative abundance. This was compared with observations from a whole blood association assay that identified with which cell type each particle system associates. PMPC-based particles displayed reduced association both with cells and with serum proteins compared with MS-based particles. Furthermore, the enrichment of specific proteins within the biomolecular corona was found to correlate with association with specific cell types. This study demonstrates how the low-fouling properties of a material are indicative of its stealth with respect to immune cell association.

GE11-PDA-Pt@USPIOs nano-formulation for relief of tumor hypoxia and MRI/PAI-guided tumor radio-chemotherapy

GE11-PDA-Pt@USPIOs can relieve tumor hypoxic conditions efficiently and are highly effective for radio-chemotherapy of EGFR-positive tumors.

Surface sulfonates lock serum albumin into a “hard” corona

Albumin is more easily displaced on a surface bearing carboxylate compared to sulfonate functionality, which controls the composition of the eventual protein corona.