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

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.

Hemostatic Dressing Immobilized with ε-poly-L-lysine and Alginate Coated Mesoporous Bioactive Glass Prevents Blood Permeation by Pseudo-Dewetting Behavior

The integration of hemostats with cotton fabrics is recognized as an effective approach to improve the hemostatic performance of dressings. However, concerns regarding the uncontrollable absorption of blood by hydrophilic dressings and the risk of distal thrombosis from shed hemostatic agents are increasingly scrutinized. To address these issues, this work develops an advanced dressing (AQG) with immobilized nano-scale mesoporous bioactive glass (MBG) to safely and durably augment hemostasis. The doubly immobilized MBGs, pre-coated with ε-poly-L-lysine and alginate, demonstrate less than 1% detachment after ultrasonic washing. Notably, this MBG layer significantly promotes the adhesion, aggregation, and activation of red blood cells and platelets, adhered five times more red blood cells and 29 times more platelets than raw dressing, respectively. Specially, with the rapid formation of protein corona and amplification of thrombin, dense fibrin network is built on MBG layer and then blocked blood permeation transversely and longitudinally, showing an autophobic pseudo-dewetting behavior and allowing AQG to concentrate blood in situ and culminate in faster hemostasis with lower blood loss. Furthermore, the potent antibacterial properties of AQG extend its potential for broader application in daily care and clinical setting.

Glycan-based scaffolds and nanoparticles as drug delivery system in cancer therapy

Glycan-based scaffolds are unique in their high specificity, versatility, low immunogenicity, and ability to mimic natural carbohydrates, making them attractive candidates for use in cancer treatment. These scaffolds are made up of glycans, which are biopolymers with well biocompatibility in the human body that can be used for drug delivery. The versatility of glycan-based scaffolds allows for the modulation of drug activity and targeted delivery to specific cells or tissues, which increases the potency of drugs and reduces side effects. Despite their promise, there are still technical challenges in the design and production of glycan-based scaffolds, as well as limitations in their therapeutic efficacy and specificity.

A Review for Uncovering the "Protein-Nanoparticle Alliance": Implications of the Protein Corona for Biomedical Applications

Understanding both the physicochemical and biological interactions of nanoparticles is mandatory for the biomedical application of nanomaterials. By binding proteins, nanoparticles acquire new surface identities in biological fluids, the protein corona. Various studies have revealed the dynamic structure and nano-bio interactions of the protein corona. The binding of proteins not only imparts new surface identities to nanoparticles in biological fluids but also significantly influences their bioactivity, stability, and targeting specificity. Interestingly, recent endeavors have been undertaken to harness the potential of the protein corona instead of evading its presence. Exploitation of this 'protein-nanoparticle alliance' has significant potential to change the field of nanomedicine. Here, we present a thorough examination of the latest research on protein corona, encompassing its formation, dynamics, recent developments, and diverse bioapplications. Furthermore, we also aim to explore the interactions at the nano-bio interface, paving the way for innovative strategies to advance the application potential of the protein corona. By addressing challenges and promises in controlling protein corona formation, this review provides insights into the evolving landscape of the 'protein-nanoparticle alliance' and highlights emerging.

Functional nanomaterials as photosensitizers or delivery systems for antibacterial photodynamic therapy

Bacterial infection is a global health problem that closely related to various diseases threatening human life. Although antibiotic therapy has been the mainstream treatment method for various bacterial infectious diseases for decades, the increasing emergence of bacterial drug resistance has brought enormous challenges to the application of antibiotics. Therefore, developing novel antibacterial strategies is of great importance. By producing reactive oxygen species (ROS) with photosensitizers (PSs) under light irradiation, antibacterial photodynamic therapy (aPDT) has emerged as a non-invasive and promising approach for treating bacterial infections without causing drug resistance. However, the insufficient therapeutic penetration, poor hydrophilicity, and poor biocompatibility of traditional PSs greatly limit the efficacy of aPDT. Recently, studies have found that nanomaterials with characteristics of favorable photocatalytic activity, surface plasmonic resonance, easy modification, and high drug loading capacity can improve the therapeutic efficacy of aPDT. In this review, we aim to provide a comprehensive understanding of the mechanism of nanomaterials-mediated aPDT and summarize the representative nanomaterials in aPDT, either as PSs or carriers for PSs. In addition, the combination of advanced nanomaterials-mediated aPDT with other therapies, including targeted therapy, gas therapy, and multidrug resistance (MDR) therapy, is reviewed. Also, the concerns and possible solutions of nanomaterials-based aPDT are discussed. Overall, this review may provide theoretical basis and inspiration for the development of nanomaterials-based aPDT.

Cancer Nanovaccines: Nanomaterials and Clinical Perspectives

Cancer nanovaccines represent a promising frontier in cancer immunotherapy, utilizing nanotechnology to augment traditional vaccine efficacy. This review comprehensively examines the current state-of-the-art in cancer nanovaccine development, elucidating innovative strategies and technologies employed in their design. It explores both preclinical and clinical advancements, emphasizing key studies demonstrating their potential to elicit robust anti-tumor immune responses. The study encompasses various facets, including integrating biomaterial-based nanocarriers for antigen delivery, adjuvant selection, and the impact of nanoscale properties on vaccine performance. Detailed insights into the complex interplay between the tumor microenvironment and nanovaccine responses are provided, highlighting challenges and opportunities in optimizing therapeutic outcomes. Additionally, the study presents a thorough analysis of ongoing clinical trials, presenting a snapshot of the current clinical landscape. By curating the latest scientific findings and clinical developments, this study aims to serve as a comprehensive resource for researchers and clinicians engaged in advancing cancer immunotherapy. Integrating nanotechnology into vaccine design holds immense promise for revolutionizing cancer treatment paradigms, and this review provides a timely update on the evolving landscape of cancer nanovaccines.

Recent Advancements and Unexplored Biomedical Applications of Green Synthesized Ag and Au Nanoparticles: A Review

Green synthesis of silver (Ag) and gold (Au) nanoparticles (NPs) has acquired huge popularity owing to their potential applications in various fields. A large number of research articles exist in the literature describing the green synthesis of Ag and Au NPs for biomedical applications. However, these findings are scattered, making it time-consuming for researchers to locate promising advancements in Ag and Au NPs synthesis and their unexplored biomedical applications. Unlike other review articles, this systematic study not only highlights recent advancements in the green synthesis of Ag and Au NPs but also explores their potential unexplored biomedical applications. The article discusses the various synthesis approaches for the green synthesis of Ag and Au NPs highlighting the emerging developments and novel strategies. Then, the article reviews the important biomedical applications of green synthesized Ag and Au NPs by critically evaluating the expected advantages. To expose future research direction in the field, the article describes the unexplored biomedical applications of the NPs. Finally, the articles discuss the challenges and limitations in the green synthesis of Ag and Au NPs and their biomedical applications. This article will serve as a valuable reference for researchers, working on green synthesis of Ag and Au NPs for biomedical applications.

Genome editing of PAR2 through targeted delivery of CRISPR-Cas9 system for alleviating acute lung inflammation via ERK/NLRP3/IL-1β and NO/iNOS signalling

Excessive and uncontrollable inflammatory responses in alveoli can dramatically exacerbate pulmonary disease progressions through vigorous cytokine releases, immune cell infiltration and protease-driven tissue damages. It is an urgent need to explore potential drug strategies for mitigating lung inflammation. Protease-activated receptor 2 (PAR2) as a vital molecular target principally participates in various inflammatory diseases via intracellular signal transduction. However, it has been rarely reported about the role of PAR2 in lung inflammation. This study applied CRISPR-Cas9 system encoding Cas9 and sgRNA (pCas9-PAR2) for PAR2 knockout and fabricated an anionic human serum albumin-based nanoparticles to deliver pCas9-PAR2 with superior inflammation-targeting efficiency and stability (TAP/pCas9-PAR2). TAP/pCas9-PAR2 robustly facilitated pCas9-PAR2 to enter and transfect inflammatory cells, eliciting precise gene editing of PAR2 in vitro and in vivo. Importantly, PAR2 deficiency by TAP/pCas9-PAR2 effectively and safely promoted macrophage polarization, suppressed pro-inflammatory cytokine releases and alleviated acute lung inflammation, uncovering a novel value of PAR2. It also revealed that PAR2-mediated pulmonary inflammation prevented by TAP/pCas9-PAR2 was mainly dependent on ERK-mediated NLRP3/IL-1β and NO/iNOS signalling. Therefore, this work indicated PAR2 as a novel target for lung inflammation and provided a potential nanodrug strategy for PAR2 deficiency in treating inflammatory diseases.

Charge-Reversible Nanoparticles: Advanced Delivery Systems for Therapy and Diagnosis

The past two decades have witnessed a rapid progress in the development of surface charge-reversible nanoparticles (NPs) for drug delivery and diagnosis. These NPs are able to elegantly address the polycation dilemma. Converting their surface charge from negative/neutral to positive at the target site, they can substantially improve delivery of drugs and diagnostic agents. By specific stimuli like a shift in pH and redox potential, enzymes, or exogenous stimuli such as light or heat, charge reversal of NP surface can be achieved at the target site. The activated positive surface charge enhances the adhesion of NPs to target cells and facilitates cellular uptake, endosomal escape, and mitochondrial targeting. Because of these properties, the efficacy of incorporated drugs as well as the sensitivity of diagnostic agents can be essentially enhanced. Furthermore, charge-reversible NPs are shown to overcome the biofilm formed by pathogenic bacteria and to shuttle antibiotics directly to the cell membrane of these microorganisms. In this review, the up-to-date design of charge-reversible NPs and their emerging applications in drug delivery and diagnosis are highlighted.

Intratumor delivery of amino-modified graphene oxide as a multifunctional photothermal agent for efficient antitumor phototherapy

Due to the high selectivity and non-invasive property, phototherapy has attracted increasing attention in the treatment of cancer. Targeted delivery and retention of photoactive agents in tumor tissue is of great significance and importance for safe and efficient phototherapy. Herein, we report a multifunctional nanomaterial photothermal agent, namely amino-modified graphene oxide (AGO) for anti-oral cancer photothermal therapy (PTT). Compared to the parental graphene oxide (GO) which has a negative charge and weak photothermal effect, AGO possesses a positive charge (∼+50 mV) and the significantly enhanced photothermal effect. Positive charge allows AGO to efficiently interact with tumor cells and retain in tumor tissue after intratumor injection. The enhanced photothermal effect allows AGO to achieve the tunable and efficient PTT. In vitro results show that AGO (15 μg/mL) reduces the viability of HSC-3 cells (oral squamous cell carcinoma cell line) to 5% under near infrared (NIR) irradiation (temperature increased to 58.4 °C). In vivo antitumor study shows that intratumor delivery of AGO (200 μg/mouse) has no inhibition effects on tumor growth (454% of initial tumor size) without NIR. With a single dose of NIR irradiation, however, AGO significantly reduces the tumor size to 25% of initial size in 1 of 4 mice, and even induces the complete tumor ablation in 3 of 4 mice. Furthermore, the injected AGO falls off along with the scab after PTT. Our findings indicate that AGO is a potential nano-photothermal agent for tunable, convenient and efficient anticancer PTT.

Semiconducting Polymer Dots Directly Stabilized with Serum Albumin: Preparation, Characterization, and Cellular Immunolabeling

Semiconducting polymer dots (Pdots) are brightly fluorescent nanoparticles of growing interest for bioanalysis and imaging. A recurring challenge with these materials is obtaining robust physical and colloidal stability and low nonspecific binding. Here, we prepared and characterized Pdots with bovine serum albumin (BSA) as the stabilizing agent (BSA-Pdots) instead of a more conventionally used amphiphilic polymer, both without and with cross-linking of the protein using glutaraldehyde (BSA(GA)-Pdots) or disuccinimidyl glutarate. Characterization included fluorescence properties; colloidal stability as a function of pH, ionic strength, and solvent perturbation; shape retention and hardness; and nonspecific binding with common assay substrates, fixed cells, and live cells. These properties were contrasted with the same properties for amphiphilic polymer-stabilized Pdots and silica-coated Pdots. On balance, the BSA-stabilized Pdots were similar or more favorable in their properties, with BSA(GA)-Pdots being especially advantageous. Bioconjugation of the BSA-stabilized Pdots was possible using amine-reactive active-ester chemistry, including biotinylation and bioorthogonal functionalization for immunoconjugation via tetrazine-strained-alkene click chemistry. These approaches were used for selective fluorescent labeling of cells based on ligand-receptor and antibody-antigen binding, respectively. Overall, direct BSA stabilization is a very promising strategy for preparing Pdots with improved physical and colloidal stability, reduced nonspecific interactions, and utility for in vitro diagnostics and other bioanalyses and imaging.

Interactions between nanoparticle corona proteins and the immune system

The corona surrounding nanoparticles (NPs) in serum contains proteins such as complement, immunoglobulins, and apolipoproteins that can interact with the immune system. This review article describes the impact of these interactions on nanomedicine stability, biodistribution, efficacy, and safety. Notably, it highlights the latest findings on the generation of antibody responses to the polyethylene glycol (PEG) component of SARS-CoV-2 mRNA vaccines and possible mechanisms of hypersensitivity reactions induced by antibodies that bind to NPs. Finally, we briefly outline how the NP interactions with immune cells can be harnessed to enhance targeted delivery of nanocargos to disease sites.

Protein Corona Formation on Lipid Nanoparticles Negatively Affects the NLRP3 Inflammasome Activation

The interaction between lipid nanoparticles (LNPs) and serum proteins, giving rise to a unique identification in the form of the protein corona, has been shown to be associated with novel recognition by cell receptors. The presence of the corona enveloping the nanoparticle strongly affects the interplay with immune cells. The immune responses mediated by protein corona can affect nanoparticle toxicity and targeting capabilities. But the intracellular signaling of LNPs after corona formation resulting in the change of nanoparticles' ability to provoke immune responses remains unclear. Therefore, a more systematic and delineated approach must be considered to present the correlation between corona complexes and the shift in nanoparticle immunogenicity. Here, we studied and reported the inhibiting effect of the absorbed proteins on the LNPs on the NLRP3 inflammasome activation, a key intracellular protein complex that modulates several inflammatory responses. Ionizable lipid as a component of LNP was observed to play an important role in modulating the activation of NLRP3 inflammasome in serum-free conditions. However, in the presence of serum proteins, the corona layer on LNPs caused a significant reduction in the inflammasome activation. Reduction in the lysosomal rupture after treatment with corona-LNPs significantly reduced inflammasome activation. Furthermore, a strong reduction of cellular uptake in macrophages after the corona formation was observed. On inspecting the uptake mechanisms in macrophages using transport inhibitors, lipid formulation was found to play a critical role in determining the endocytic pathways for the LNPs in macrophages. This study highlights the need to critically analyze the protein interactions with nanomaterials and their concomitant adaptability with immune cells to evaluate nano-bio surfaces and successfully design nanomaterials for biological applications.

Variations in metabolite profiles of serum coronas produced around PEGylated liposomal drugs by surface property

Understanding biomolecular coronas that spontaneously occur around nanocarriers (NCs) in biological fluids is critical to nanomedicine as the coronas influence the behaviors of NCs in biological systems. In contrast to extensive investigations of protein coronas over the past decades, understanding of the coronas of biomolecules beyond proteins, e.g., metabolites, has been rather limited despite such biochemicals being ubiquitously involved in the coronas, which may influence the bio-nano interactions and thus exert certain biological impacts. In this study, serum biomolecular coronas, in particular the coronas of metabolites including lipids, around PEGylated doxorubicin-loaded liposomes with different surface property were investigated. The surface properties of liposomal drugs varied in terms of surface charge and PEGylation density by employing different ionic lipids such as DOTAP and DOPS and different concentrations of PEGylation lipids in liposome formulation. Using the liposomal drugs, the influence of the surface property on the serum metabolite profiles in the coronas was traced for target molecules of 220 lipids and 88 hydrophilic metabolites. From the results, it was found that metabolites rather than proteins mainly constitute the serum coronas on the liposomal drugs. Most of the serum metabolites were found to be retained in the coronas but with altered abundances. Depending on their class, lipids exhibited a different dependence on the surface property. However, overall, lipids appeared to favor corona formation on more negatively charged and PEGylated surfaces. Hydrophilic metabolites also exhibited a similar propensity for corona formation. This study on the surface dependence of metabolite corona formation provides a fundamental contribution toward attaining a comprehensive understanding of biomolecular coronas, which will be critical to the development of efficient nanomedicine.

On the mechanism of tissue-selective gene delivery by lipid nanoparticles

The era of nucleic acid nanomedicine has arrived, as evidenced by Patisiran, a small interfering RNA (siRNA) encapsulated lipid nanoparticle (LNP), and mRNA-loaded LNPs used in COVID-19 vaccines. The diversity of nano-designs for delivering nucleic acid molecules tested in Phase II/III clinical trials reflects the potential of these technologies. These breakthroughs in non-viral gene delivery, including the use of LNPs, have attracted substantial interest worldwide for developing more effective drugs. A next step in this field is to target tissues other than the liver, which requires significant research efforts and material development. However, mechanistic studies in this area are lacking. This study compares two types of LNPs with different tissue-selectivity for delivering plasmid DNA (pDNA), one being liver-selective and the other spleen-selective, in an effort to understand the mechanisms responsible for differences in gene expression of delivered genes. We observed little difference in the biodistribution of these two LNPs despite the 100-1000-fold differences in gene expression. We then quantified the amount of delivered pDNA and mRNA expression in each tissue by quantitative real-time PCR (qPCR) to evaluate various intracellular processes, such as nuclear delivery, transcription and translation. The results showed a >100-fold difference in the translation step but there were little differences in amount of pDNA delivered to the nucleus or the amount of mRNA expression for the two LNP deliveries. Our findings suggest that endogenous factors affect gene expression efficiency not the extent of biodistribution.

Dual stimuli-responsive mesoporous silica nanoparticles for efficient loading and smart delivery of doxorubicin to cancer with RGD-integrin targeting

The recent progress in nanoparticle applications, such as tumor-targeting, has enabled specific delivery of chemotherapeutics to malignant tissues with enhanced local efficacy while limiting side effects. However, existing delivery systems leave much room for improvement in terms of achieving enhanced colloidal stability in fluid medium, efficient targeting of intended sites, and effective release of therapeutic drugs into diseased cells. Here, an efficient stimuli-responsive nanocarrier for mammalian cells, termed RGD-NAMs, was developed, which enabled temperature- and pH-sensitive release of drug loads. The RGD-NAMs comprise two parts: a stimuli-responsive copolymer shell (NIBIm-AA-RGD) and drug-container core (MSNs). The RGD-NAMs have a stable drug-loading capacity with a marked difference in the release rate depending on the temperature and pH conditions. The RGD-NAMs also exhibit high colloidal stability in SBF (Stimulated body fluid) solutions and minimal toxicity in skeletal myoblasts (C2C12) and bovine arterial endothelial cells (BAEC). The doxorubicin-loaded RGD-NAMs induced a cytotoxic effect in a dose-dependent manner, which was furthered by an increase in temperature from 37 to 40 °C. Moreover, significant control of the release rate and the amount were achieved through pH change. This novel, smart drug-delivery system with high responsiveness to temperature and pH changes has wide application prospects in biomedical fields, including the theragnosis of tumors and vascular diseases.

The interplay between PEGylated nanoparticles and blood immune system

During the last two decades, an increasing number of reports have pointed out that the immunogenicity of polyethylene glycol (PEG) may trigger accelerated blood clearance (ABC) and hypersensitivity reaction (HSR) to PEGylated nanoparticles, which could make PEG modification counterproductive. These phenomena would be detrimental to the efficacy of the load and even life-threatening to patients. Consequently, further elucidation of the interplay between PEGylated nanoparticles and the blood immune system will be beneficial to developing and applying related formulations. Many groups have worked to unveil the relevance of structural factors, dosing schedule, and other factors to the ABC phenomenon and hypersensitivity reaction. Interestingly, the results of some reports seem to be difficult to interpret or contradict with other reports. In this review, we summarize the physiological mechanisms of PEG-specific immune response. Moreover, we speculate on the potential relationship between the induction phase and the effectuation phase to explain the divergent results in published reports. In addition, the role of nanoparticle-associated factors is discussed based on the classification of the action phase. This review may help researchers to develop PEGylated nanoparticles to avoid unfavorable immune responses based on the underlying mechanism.

A high-throughput approach of screening nanoparticles for targeted delivery of mRNA

The ability to specifically and efficiently deliver mRNA to target locations could unlock therapeutic strategies for a range of diseases. Rhym et al.1 have developed an advanced approach for high-throughput, in vivo screening of tissue-targeting nanoparticle formulations, utilizing peptide barcoding and liquid chromatography with tandem mass spectrometry.

A General and Efficient Strategy for Gene Delivery Based on Tea Polyphenols Intercalation and Self-Polymerization

Gene therapy that employs therapeutic nucleic acids to modulate gene expression has shown great promise for diseases therapy, and its clinical application relies on the development of effective gene vector. Herein a novel gene delivery strategy by just using natural polyphenol (-)-epigallocatechin-3-O-gallate (EGCG) as raw material is reported. EGCG first intercalates into nucleic acids to yield a complex, which then oxidizes and self-polymerizes to form tea polyphenols nanoparticles (TPNs) for effective nucleic acids encapsulation. This is a general method to load any types of nucleic acids with single or double strands and short or long sequences. Such TPNs-based vector achieves comparable gene loading capacity to commonly used cationic materials, but showing lower cytotoxicity. TPNs can effectively penetrate inside cells, escape from endo/lysosomes, and release nucleic acids in response to intracellular glutathione to exert biological functions. To demonstrate the in vivo application, an anti-caspase-3 small interfering ribonucleic acid is loaded into TPNs to treat concanavalin A-induced acute hepatitis, and excellent therapeutic efficacy is obtained in combination with the intrinsic activities of TPNs vector. This work provides a simple, versatile, and cost-effective gene delivery strategy. Given the biocompatibility and intrinsic biofunctions, this TPNs-based gene vector holds great potential to treat various diseases.

The role of protein corona on nanodrugs for organ-targeting and its prospects of application

Nowadays, nanodrugs become a hotspot in the high-end medical field. They have the ability to deliver drugs to reach their destination more effectively due to their unique properties and flexible functionalization. However, the fate of nanodrugs in vivo is not the same as those presented in vitro, which indeed influenced their therapeutic efficacy in vivo. When entering the biological organism, nanodrugs will first come into contact with biological fluids and then be covered by some biomacromolecules, especially proteins. The proteins adsorbed on the surface of nanodrugs are known as protein corona (PC), which causes the loss of prospective organ-targeting abilities. Fortunately, the reasonable utilization of PC may determine the organ-targeting efficiency of systemically administered nanodrugs based on the diverse expression of receptors on cells in different organs. In addition, the nanodrugs for local administration targeting diverse lesion sites will also form unique PC, which plays an important role in the therapeutic effect of nanodrugs. This article introduced the formation of PC on the surface of nanodrugs and summarized the recent studies about the roles of diversified proteins adsorbed on nanodrugs and relevant protein for organ-targeting receptor through different administration pathways, which may deepen our understanding of the role that PC played on organ-targeting and improve the therapeutic efficacy of nanodrugs to promote their clinical translation.

The D-amino acid oxidase-carbon nanotubes: evaluation of cytotoxicity and biocompatibility of a potential anticancer nanosystem

The 'enzyme prodrug therapy' represents a promising strategy to overcome limitations of current cancer treatments by the systemic administration of prodrugs, converted by a foreign enzyme into an active anticancer compound directly in tumor sites. One example is D-amino acid oxidase (DAAO), a dimeric flavoenzyme able to catalyze the oxidative deamination of D-amino acids with production of hydrogen peroxide, a reactive oxygen species (ROS), able to favor cancer cells death. A DAAO variant containing five aminoacidic substitutions (mDAAO) was demonstrated to possess a better therapeutic efficacy under low O2 concentration than wild-type DAAO (wtDAAO). Recently, aiming to design promising nanocarriers for DAAO, multi-walled carbon nanotubes (MWCNTs) were functionalized with polyethylene glycol (PEG) to reduce their tendency to aggregation and to improve their biocompatibility. Here, wtDAAO and mDAAO were adsorbed on PEGylated MWCNTs and their activity and cytotoxicity were tested. While PEG-MWCNTs-DAAOs have shown a higher activity than pristine MWCNTs-DAAO (independently on the DAAO variant used), PEG-MWCNTs-mDAAO showed a higher cytotoxicity than PEG-MWCNTs-wtDAAO at low O2 concentration. In order to evaluate the nanocarriers' biocompatibility, PEG-MWCNTs-DAAOs were incubated in human serum and the composition of protein corona was investigated via nLC-MS/MS, aiming to characterize both soft and hard coronas. The mDAAO variant has influenced the bio-corona composition in both number of proteins and presence of opsonins and dysopsonins: notably, the soft corona of PEG-MWCNTs-mDAAO contained less proteins and was more enriched in proteins able to inhibit the immune response than PEG-MWCNTs-wtDAAO. Considering the obtained results, the PEGylated MWCNTs conjugated with the mDAAO variant seems a promising candidate for a selective antitumor oxidative therapy: under anoxic-like conditions, this novel drug delivery system showed a remarkable cytotoxic effect controlled by the substrate addition, against different tumor cell lines, and a bio-corona composition devoted to prolong its blood circulation time, thus improving the drug's biodistribution.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03568-1.

Challenges and opportunities in delivering oral peptides and proteins

INTRODUCTION

Rapid advances in bioengineering enable the use of complex proteins as therapeutic agents to treat diseases. Compared with conventional small molecule drugs, proteins have multiple advantages, including high bioactivity and specificity with low toxicity. Developing oral dosage forms with active proteins is a route to improve patient compliance and significantly reduce production costs. However, the gastrointestinal environment remains a challenge to this delivery path due to enzymatic degradation, low permeability, and weak absorption, leading to reduced delivery efficiency and poor clinical outcomes.

AREAS COVERED

This review describes the barriers to oral delivery of peptides and complex proteins, current oral delivery strategies utilized and the opportunities and challenges ahead to try and circumvent these barriers. Oral protein drugs on the market and clinical trials provide insights and approaches for advancing delivery strategies.

EXPERT OPINION

Although most current studies on oral protein delivery rely on in vitro and in vivo animal data, the safety and limitations of the approach in humans remain uncertain. The shortage of clinical data limits the development of new or alternative strategies. Therefore, designing appropriate oral delivery strategies remains a significant challenge and requires new ideas, innovative design strategies and novel model systems.

Identification of the Proteins Determining the Blood Circulation Time of Nanoparticles

The therapeutic efficacy and adverse impacts of nanoparticles (NPs) are strongly dependent on their systemic circulation time. The corona proteins adsorbed on the NPs determine their plasma half-lives, and hence, it is crucial to identify the proteins shortening or extending their circulation time. In this work, the in vivo circulation time and corona composition of superparamagnetic iron oxide nanoparticles (SPIONs) with different surface charges/chemistries were analyzed over time. SPIONs with neutral and positive charges showed the longest and shortest circulation times, respectively. The most striking observation was that corona-coated NPs with similar opsonin/dysopsonin content showed different circulation times, implying these biomolecules are not the only contributing factors. Long-circulating NPs adsorb higher concentrations of osteopontin, lipoprotein lipase, coagulation factor VII, matrix Gla protein, secreted phosphoprotein 24, alpha-2-HS-glycoprotein, and apolipoprotein C-I, while short-circulating NPs adsorb higher amounts of hemoglobin. Therefore, these proteins may be considered to be determining factors governing the NP systemic circulation time.

Analysis of PEG-lipid anchor length on lipid nanoparticle pharmacokinetics and activity in a mouse model of traumatic brain injury

Traumatic brain injury (TBI) affects millions of people worldwide, yet there are currently no therapeutics that address the long-term impairments that develop in a large portion of survivors. Lipid nanoparticles (LNPs) are a promising therapeutic strategy that may address the molecular basis of TBI pathophysiology. LNPs are the only non-viral gene delivery platform to achieve clinical success, but systemically administered formulations have only been established for targets in the liver. In this work, we evaluated the pharmacokinetics and activity of LNPs formulated with polyethylene glycol (PEG)-lipids of different anchor lengths when systemically administered to a mouse model of TBI. We observed an increase in LNP accumulation and activity in the injured brain hemisphere compared to the uninjured contralateral brain hemisphere. Interestingly, transgene expression mediated by LNPs was more durable in injured brain tissue compared to off-target organs when compared between 4 and 24 hours. The PEG-lipid is an important component of LNP formulation necessary for the stable formation and storage of LNPs, but the PEG-lipid structure and content also has an impact on LNP function. LNP formulations containing various ratios of PEG-lipid with C18 (DSPE-PEG) and C14 (DMG-PEG) anchors displayed similar physicochemical properties, independent of the PEG-lipid compositions. As the proportion of DSPE-PEG was increased in formulations, blood circulation times of LNPs increased and the duration of expression increased. We also evaluated diffusion of LNPs after convection enhanced delivery (CED) in healthy brains and found LNPs distributed >1 mm away from the injection site. Understanding LNP pharmacokinetics and activity in TBI models and the impact of PEG-lipid anchor length informs the design of LNP-based therapies for TBI after systemic administration.

Bionic natural small molecule co-assemblies towards targeted and synergistic Chemo/PDT/CDT

BACKGROUND

Multi-component nano-delivery systems based on chemotherapy (chemo)- photodynamic therapy (PDT)- chemodynamic therapy (CDT) have gained increased attention as a promising strategy to improve clinical outcomes in cancer treatment. However, there remains a challenge in developing biodegradable, biocompatible, less toxic, yet highly efficient multicomponent nanobased drug delivery systems (DDS). Here, our study presents the screening and development of a novel DDS based on co-assemblies natural small molecule (NSMs). These molecules (oleanolic acid, and betulinic acid) are combined with photosensitizers Chlorine6 (Ce6) and Cu²⁺ that are encapsulated by tumor cell membranes. This nanocarrier encapsulated in tumor cell membranes achieved good tumor targeting and a significant improvement in tumor accumulation.

METHODS

A reprecipitation method was used to prepare the co-assembled nanocarrier, followed by the introduction of Cu^2 + into the DDS (OABACe6 NPs). Then, by wrapping the surface of NPs with the cell membranes of 4T1 which is a kind of mouse breast cancer cells (CM@OABACe6/Cu NPs). and analysis of its structure and size distribution with UV-Vis, XPS, FT-IR, SEM, TEM, and DLS. The synergistic effects of in vitro chemotherapy, CDT and PDT and targeting were also validated by cellular and animal studies.

RESULTS

It was shown that CM@OABACe6/Cu NPs achieved good tumor targeting and a significant improvement in tumor accumulation. In the composite nano-assembly, the NSMs work together with the Ce6 to provide effective and safe chemo and PDT. Moreover, the effect of reduced PDT due to the depletion of reactive oxygen species (ROS) by excess glutathione (GSH) in the tumor can be counteracted when Cu^2 + is introduced. More importantly, it also confers CDT through a Fenton-like catalytic reaction with H₂O overexpressed at the tumor site.

CONCLUSIONS

By constructing CM@OABACe6/Cu NPs with homologous targeting, we create a triple synergistic platform for cancer therapy using PDT, chemo, and CDT. We propose here a novel combinatorial strategy for designing more naturally co-assembled small molecules, especially for the development of multifunctional synergistic therapies that utilize NSMs.

Harnessing sortase A transpeptidation for advanced targeted therapeutics and vaccine engineering

The engineering of potent prophylactic and therapeutic complexes has always required careful protein modification techniques with seamless capabilities. In this light, methods that favor unobstructed multivalent targeting and correct antigen presentations remain essential and very demanding. Sortase A (SrtA) transpeptidation has exhibited these attributes in various settings over the years. However, its applications for engineering avidity-inspired therapeutics and potent vaccines have yet to be significantly noticed, especially in this era where active targeting and multivalent nanomedications are in great demand. This review briefly presents the SrtA enzyme and its associated transpeptidation activity and describes interesting sortase-mediated protein engineering and chemistry approaches for achieving multivalent therapeutic and antigenic responses. The review further highlights advanced applications in targeted delivery systems, multivalent therapeutics, adoptive cellular therapy, and vaccine engineering. These innovations show the potential of sortase-mediated techniques in facilitating the development of simple plug-and-play nanomedicine technologies against recalcitrant diseases and pandemics such as cancer and viral infections.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Photothermal and natural activity-based synergistic antibacterial effects of Ti3C2Tx MXene-loaded chitosan hydrogel against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) has strong resistance to antibiotic therapy. In this regard, developing antibiotic-free antibacterial agents is of great significance to treat MRSA infections. Herein, we loaded Ti₃C₂T_x MXene nanomaterial in the non-crosslinked chitosan (CS) hydrogel. The obtained MX-CS hydrogel is expected to not only adsorb MRSA cells via CS-MRSA interactions, but also gather the MXene-induced photothermal hyperthermia, achieving the efficient and intensive anti-MRSA photothermal therapy. As a result, under NIR irradiation (808 nm, 1.6 W/cm², 5 min), MX-CS showed a greater photothermal effect than MXene alone did (30 μg/mL, 49.9 °C for MX-CS and 46.5 °C for MXene). Importantly, MRSA cells were rapidly adsorbed on MX-CS hydrogel (containing 30 μg/mL MXene) and completely inhibited (99.18 %) under NIR irradiation for 5 min. In contrast, MXene (30 μg/mL) and CS hydrogel alone only inhibited 64.52 % and 23.72 % MRSA, respectively, significantly lower than the inhibition caused by MX-CS (P < 0.001). Interestingly, when the hyperthermia was depleted by a 37 °C water bath, the bacterial inhibition rate of MX-CS significantly decreased to 24.65 %. In conclusion, MX-CS hydrogel has a remarkable synergistic anti-MRSA activity by gathering MRSA cells and MXene-induced hyperthermia, and may have great potentials in treating MRSA-infected diseases.

Toxicity evaluation of silica nanoparticles for delivery applications

Silica nanoparticles (SiNPs) are being explored as nanocarriers for therapeutics delivery, which can address a number of intrinsic drawbacks of therapeutics. To translate laboratory innovation into clinical application, their potential toxicity has been of great concern. This review attempts to comprehensively summarize the existing literature on the toxicity assessment of SiNPs. The current data suggest that the composition of SiNPs, their physicochemical properties, their administration route, their frequency and duration of administration, and the sex of animal models are related to their tissue and blood toxicity, immunotoxicity, and genotoxicity. However, the correlation between in vitro and in vivo toxicity has not been well established, mainly because both the in vitro and the in vivo-dosed quantities are unrealistic. This article also discusses important factors to consider in the toxicology of SiNPs and current approaches to reducing their toxicity. The aim is to give readers a better understanding of the toxicology of silica nanoparticles and to help identify key gaps in knowledge and techniques.

Novel Bovine Serum Albumin-Decorated–Nanostructured Lipid Carriers Able to Modulate Apoptosis and Cell-Cycle Response in Ovarian, Breast, and Colon Tumoral Cells

A novel nanoscale approach was developed for the improved cellular internalization of hybrid bovine serum albumin–lipid nanocarriers loaded with piperine (NLC-Pip–BSA) in different tumor cells. The effect of the BSA-targeted–NLC-Pip and untargeted-NLC-Pip on the viability, proliferation, and levels of cell-cycle damage and apoptosis in the colon (LoVo), ovarian (SKOV3) and breast (MCF7) adenocarcinoma cell lines was comparatively discussed. NLCs were characterized concerning particle size, morphology, zeta potential, phytochemical encapsulation efficiency, ATR-FTIR, and fluorescence spectroscopy. The results showed that NLC-Pip–BSA showed a mean size below 140 nm, a zeta potential of −60 mV, and an entrapment efficiency of 81.94% for NLC-Pip and 80.45% for NLC-Pip–BSA. Fluorescence spectroscopy confirmed the coating of the NLC with the albumin. By MTS and RTCA assays, NLC-Pip–BSA showed a more pronounced response against the LoVo colon cell line and MCF-7 breast tumor cell lines than against the ovarian SKOV-3 cell line. Flow cytometry assay demonstrated that the targeted NLC-Pip had more cytotoxicity and improved apoptosis than the untargeted ones in MCF-7 tumor cells (p < 0.05). NLC-Pip caused a significant increase in MCF-7 breast tumor cell apoptosis of ~8X, while NLC-Pip–BSA has shown an 11-fold increase in apoptosis.

The protein corona from nanomedicine to environmental science

The protein corona spontaneously develops and evolves on the surface of nanoscale materials when they are exposed to biological environments, altering their physiochemical properties and affecting their subsequent interactions with biosystems. In this Review, we provide an overview of the current state of protein corona research in nanomedicine. We next discuss remaining challenges in the research methodology and characterization of the protein corona that slow the development of nanoparticle therapeutics and diagnostics, and we address how artificial intelligence can advance protein corona research as a complement to experimental research efforts. We then review emerging opportunities provided by the protein corona to address major issues in healthcare and environmental sciences. This Review details how mechanistic insights into nanoparticle protein corona formation can broadly address unmet clinical and environmental needs, as well as enhance the safety and efficacy of nanobiotechnology products.

Design, Synthesis, Characterization, and Evaluation of the Anti-HT-29 Colorectal Cell Line Activity of Novel 8-Oxyquinolinate-Platinum(II)-Loaded Nanostructured Lipid Carriers Targeted with Riboflavin

Colorectal cancer is occasionally called colon or rectal cancer, depending on where cancer begins to form, and is the second leading cause of cancer death among both men and women. The platinum-based [PtCl(8-O-quinolinate)(dmso)] (8-QO-Pt) compound has demonstrated encouraging anticancer activity. Three different systems of 8-QO-Pt-encapsulated nanostructured lipid carriers (NLCs) with riboflavin (RFV) were investigated. NLCs of myristyl myristate were synthesized by ultrasonication in the presence of RFV. RFV-decorated nanoparticles displayed a spherical shape and a narrow size dispersion in the range of 144-175 nm mean particle diameter. The 8-QO-Pt-loaded formulations of NLC/RFV with more than 70% encapsulation efficiency showed sustained in vitro release for 24 h. Cytotoxicity, cell uptake, and apoptosis were evaluated in the HT-29 human colorectal adenocarcinoma cell line. The results revealed that 8-QO-Pt-loaded formulations of NLC/RFV showed higher cytotoxicity than the free 8-QO-Pt compound at 5.0 µM. All three systems exhibited different levels of cellular internalization. Moreover, the hemotoxicity assay showed the safety profile of the formulations (less than 3.7%). Taken together, RFV-targeted NLC systems for drug delivery have been investigated for the first time in our study and the results are promising for the future of chemotherapy in colon cancer treatment.

Protein adsorption determines pulmonary cell uptake of lipid-based nanoparticles

The inhalable administration of lipid nanoparticles is an effective strategy for localised delivery of therapeutics against various lung diseases. Of this, improved intracellular delivery of pharmaceuticals for infectious disease and cancer management is of high significance. However, the influence of lipid nanoparticle composition and structure on uptake in pulmonary cell lines, especially in the presence of biologically relevant media is poorly understood. Here, the uptake of lamellar (liposomes) versus non-lamellar (cubosomes) lipid nanoparticles in macrophages and lung epithelial cells was quantified and the influence of bronchoalveolar lavage fluid (BALF), containing native pulmonary protein and surfactant molecules is determined. Cubosome uptake in both macrophages and epithelial cells was strongly mediated by a high percentage of molecular function regulatory and binding proteins present within the protein corona. In contrast, the protein corona did not influence the uptake of liposomes in epithelial cells. In macrophages, the proteins mediated a rapid internalisation, followed by exocytosis of liposomes after 6 h incubation. These findings on the influence of biological fluid in regulating lipid nanoparticle uptake mechanisms may guide future development of optimal intracellular delivery systems for therapeutics via the pulmonary route.

Antitumor therapy for breast cancer: Focus on tumor-associated macrophages and nanosized drug delivery systems

BACKGROUND

In breast cancer (BC), tumor-associated macrophages (TAMs) are an important component of the tumor microenvironment and are closely related to poor prognosis. A growing number of studies have focused on the role of TAMs in BC progression and therapeutic strategies targeting TAMs. As an emerging treatment, the application of nanosized drug delivery systems (NDDSs) in the treatment of BC by targeting TAMs has attracted much attention.

AIMS

This review is to summarize the characteristics and treatment strategies targeting TAMs in BC and to clarify the applications of NDDSs targeting TAMs in the treatment of BC by targeting TAMs.

MATERIALS & METHODS

The existing results related to characteristics of TAMs in BC, BC treatment strategies by targeting TAMs, and the applications of NDDSs in these strategies are described. Through analyzing these results, the advantages and disadvantages of the treatment strategies using NDDSs are discussed, which could provide advices on designing NDDSs for BC treatment.

RESULTS

TAMs are one of the most prominent noncancer cell types in BC. TAMs not only promote angiogenesis, tumor growth and metastasis but also lead to therapeutic resistance and immunosuppression. Mainly four strategies have been used to target TAMs for BC therapy, which include depleting macrophages, blocking recruitment, reprogramming to attain an anti-tumor phenotype, and increasing phagocytosis. Since NDDSs can efficiently deliver drugs to TAMs with low toxicity, they are promising approaches for targeting TAMs in tumor therapy. NDDSs with various structures can deliver immunotherapeutic agents and nucleic acid therapeutics to TAMs. In addition, NDDSs can realize combination therapies.

DISCUSSION

TAMs play a critical role in the progression of BC. An increasing number of strategies have been proposed to regulate TAMs. Compared with free drugs, NDDSs targeting TAMs improve drug concentration, reduce toxicity and realize combination therapies. However, in order to achieve better therapeutic efficacy, there are still some disadvantages that need to be considered in the design of NDDSs.

CONCLUSION

TAMs play an important role in the progression of BC, and targeting TAMs is a promising strategy for BC therapy. In particular, NDDSs targeting TAMs have unique advantages and are potential treatments for BC.

Customizing delivery nano-vehicles for precise brain tumor therapy

Although some tumor has become a curable disease for many patients, involvement of the central nervous system (CNS) is still a major concern. The blood-brain barrier (BBB), a special structure in the CNS, protects the brain from bloodborne pathogens via its excellent barrier properties and hinders new drug development for brain tumor. Recent breakthroughs in nanotechnology have resulted in various nanovehicless (NPs) as drug carriers to cross the BBB by different strategys. Here, the complex compositions and special characteristics of causes of brain tumor formation and BBB are elucidated exhaustively. Additionally, versatile drug nanovehicles with their recent applications and their pathways on different drug delivery strategies to overcome the BBB obstacle for anti-brain tumor are briefly discussed. Customizing nanoparticles for brain tumor treatments is proposed to improve the efficacy of brain tumor treatments via drug delivery from the gut to the brain. This review provides a broad perspective on customizing delivery nano-vehicles characteristics facilitate drug distribution across the brain and pave the way for the creation of innovative nanotechnology-based nanomaterials for brain tumor treatments.

Nebulization of Model Hydrogel Nanoparticles to Macrophages at the Air-Liquid Interface

Nanoparticle evaluation within the pulmonary airspace has increasingly important implications for human health, with growing interest from drug delivery, environmental, and toxicology fields. While there have been widespread investigations of nanoparticle physiochemical properties following many routes of administration, nanoparticle behavior at the air-liquid interface (ALI) is less well-characterized. In this work, we fabricate two formulations of poly(ethylene)-glycol diacrylate (PEGDA)-based model nanoparticles to establish an in vitro workflow allowing evaluation of nanoparticle charge effects at the ALI. Both cationic and anionic PEGDA formulations were synthesized with similar hydrodynamic diameters around ~225 nm and low polydispersity, with expected surface charges corresponding with the respective functional co-monomer. We find that both formulations are readily nebulized from an aqueous suspension in a commercial Aeroneb® Lab Nebulizer, but the aqueous delivery solution served to slightly increase the overall hydrodynamic and geometric size of the cationic particle formulation. However, nanoparticle loading at 50 μg/ml of either formulation did not influence the resultant aerosol diameter from the nebulizer. To assess aerosol delivery in vitro, we designed a 3D printed adapter capable of ensuring aerosol delivery to transwell 24-well culture plates. Nanoparticle uptake by macrophages was compared between traditional cell culture techniques and that of ALI-cultured macrophages following aerosol delivery. Cell viability was unaffected by nanoparticle delivery using either method. However, only traditional cell culture methods demonstrated significant uptake that was dependent on the nanoparticle surface charge. Concurrently, ALI culture resulted in lower metabolic activity of macrophages than those in traditional cell culture, leading to lower overall nanoparticle uptake at ALI. Overall, this work demonstrates that base-material similarities between both particle formulations provide an expected consistency in aerosol delivery regardless of the nanoparticle surface charge and provides an important workflow that enables a holistic evaluation of aerosolizable nanoparticles.

Superparamagnetic Iron Oxide Nanoparticles (SPION): From Fundamentals to State-of-the-Art Innovative Applications for Cancer Therapy

Despite significant advances in cancer therapy over the years, its complex pathological process still represents a major health challenge when seeking effective treatment and improved healthcare. With the advent of nanotechnologies, nanomedicine-based cancer therapy has been widely explored as a promising technology able to handle the requirements of the clinical sector. Superparamagnetic iron oxide nanoparticles (SPION) have been at the forefront of nanotechnology development since the mid-1990s, thanks to their former role as contrast agents for magnetic resonance imaging. Though their use as MRI probes has been discontinued due to an unfavorable cost/benefit ratio, several innovative applications as therapeutic tools have prompted a renewal of interest. The unique characteristics of SPION, i.e., their magnetic properties enabling specific response when submitted to high frequency (magnetic hyperthermia) or low frequency (magneto-mechanical therapy) alternating magnetic field, and their ability to generate reactive oxygen species (either intrinsically or when activated using various stimuli), make them particularly adapted for cancer therapy. This review provides a comprehensive description of the fundamental aspects of SPION formulation and highlights various recent approaches regarding in vivo applications in the field of cancer therapy.

Anticancer properties of bacterial cellulose membrane containing ethanolic extract of Epilobium angustifolium L

Epilobium angustifolium L. is a medicinal plant well known for its anti-inflammatory, antibacterial, antioxidant, and anticancer properties related to its high polyphenols content. In the present study, we evaluated the antiproliferative properties of ethanolic extract of E. angustifolium (EAE) against normal human fibroblasts (HDF) and selected cancer cell lines, including melanoma (A375), breast (MCF7), colon (HT-29), lung (A549) and liver (HepG2). Next, bacterial cellulose (BC) membranes were applied as a matrix for the controlled delivery of the plant extract (BC-EAE) and characterized by thermogravimetry (TG), infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) images. In addition, EAE loading and kinetic release were defined. Finally, the anticancer activity of BC-EAE was evaluated against the HT-29 cell line, which presented the highest sensitivity to the tested plant extract (IC₅₀ = 61.73 ± 6.42 µM). Our study confirmed the biocompatibility of empty BC and the dose and time-dependent cytotoxicity of the released EAE. The plant extract released from BC-2.5%EAE significantly reduced cell viability to 18.16% and 6.15% of the control values and increased number apoptotic/dead cells up to 37.53% and 66.90% after 48 and 72 h of treatment, respectively. In conclusion, our study has shown that BC membranes could be used as a carrier for the delivery of higher doses of anticancer compounds released in a sustained manner in the target tissue.

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.

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.

Polymer nanocarriers for targeted local delivery of agents in treating brain tumors

Glioblastoma (GBM), the deadliest brain cancer, presents a multitude of challenges to the development of new therapies. The standard of care has only changed marginally in the past 17 years, and few new chemotherapies have emerged to supplant or effectively combine with temozolomide. Concurrently, new technologies and techniques are being investigated to overcome the pharmacokinetic challenges associated with brain delivery, such as the blood brain barrier (BBB), tissue penetration, diffusion, and clearance in order to allow for potent agents to successful engage in tumor killing. Alternative delivery modalities such as focused ultrasound and convection enhanced delivery allow for the local disruption of the BBB, and the latter in particular has shown promise in achieving broad distribution of agents in the brain. Furthermore, the development of polymeric nanocarriers to encapsulate a variety of cargo, including small molecules, proteins, and nucleic acids, have allowed for formulations that protect and control the release of said cargo to extend its half-life. The combination of local delivery and nanocarriers presents an exciting opportunity to address the limitations of current chemotherapies for GBM toward the goal of improving safety and efficacy of treatment. However, much work remains to establish standard criteria for selection and implementation of these modalities before they can be widely implemented in the clinic. Ultimately, engineering principles and nanotechnology have opened the door to a new wave of research that may soon advance the stagnant state of GBM treatment development.

Radiolabeling, Quality Control and In Vivo Imaging of Multimodal Targeted Nanomedicines

Following our previous study on the development of EGFR-targeted nanomedicine (NM-scFv) for the active delivery of siRNA in EGFR-positive cancers, this study focuses on the development and the quality control of a radiolabeling method to track it in in vivo conditions with nuclear imaging. Our NM-scFv is based on the electrostatic complexation of targeted nanovector (NV-scFv), siRNA and two cationic polymers. NV-scFv comprises an inorganic core, a fluorescent dye, a polymer layer and anti-EGFR ligands. To track NM-scFv in vivo with nuclear imaging, the DTPA chemistry was used to radiolabel NM-scFv with 111In. DTPA was thiolated and introduced onto NV-scFv via the maleimide chemistry. To obtain suitable radiolabeling efficiency, different DTPA/NV-scFv ratios were tested, including 0.03, 0.3 and 0.6. At the optimized ratio (where the DTPA/NV-scFv ratio was 0.3), a high radiolabeling yield was achieved (98%) and neither DTPA-derivatization nor indium-radiolabeling showed any impact on NM-scFv’s physicochemical characteristics (DH ~100 nm, PDi < 0.24). The selected NM-scFv-DTPA demonstrated good siRNA protection capacity and comparable in vitro transfection efficiency into EGFR-overexpressing cells in comparison to that of non-derivatized NM-scFv (around 67%). Eventually, it was able to track both qualitatively and quantitatively NM-scFv in in vivo environments with nuclear imaging. Both the radiolabeling and the NM-scFv showed a high in vivo stability level. Altogether, a radiolabeling method using DTPA chemistry was developed with success in this study to track our NM-scFv in in vivo conditions without any impact on its active targeting and physicochemical properties, highlighting the potential of our NM-scFv for future theranostic applications in EGFR-overexpressing cancers.

Photonic and magnetic materials for on-demand local drug delivery

Nanomedicine has been considered a promising tool for biomedical research and clinical practice in the 21st century because of the great impact nanomaterials could have on human health. The generation of new smart nanomaterials, which enable time- and space-controlled drug delivery, improve the limitations of conventional treatments, such as non-specific targeting, poor biodistribution and permeability. These smart nanomaterials can respond to internal biological stimuli (pH, enzyme expression and redox potential) and/or external stimuli (such as temperature, ultrasound, magnetic field and light) to further the precision of therapies. To this end, photonic and magnetic nanoparticles, such as gold, silver and iron oxide, have been used to increase sensitivity and responsiveness to external stimuli. In this review, we aim to report the main and most recent systems that involve photonic or magnetic nanomaterials for external stimulus-responsive drug release. The uniqueness of this review lies in highlighting the versatility of integrating these materials within different carriers. This leads to enhanced performance in terms of in vitro and in vivo efficacy, stability and toxicity. We also point out the current regulatory challenges for the translation of these systems from the bench to the bedside, as well as the yet unresolved matter regarding the standardization of these materials.

Biological Features of Nanoparticles: Protein Corona Formation and Interaction with the Immune System

Nanoparticles (NPs) are versatile candidates for nanomedical applications due to their unique physicochemical properties. However, their clinical applicability is hindered by their undesirable recognition by the immune system and the consequent immunotoxicity, as well as their rapid clearance in vivo. After injection, NPs are usually covered with layers of proteins, called protein coronas (PCs), which alter their identity, biodistribution, half-life, and efficacy. Therefore, the characterization of the PC is for in predicting the fate of NPs in vivo. The aim of this review was to summarize the state of the art regarding the intrinsic factors closely related to the NP structure, and extrinsic factors that govern PC formation in vitro. In addition, well-known opsonins, including complement, immunoglobulins, fibrinogen, and dysopsonins, such as histidine-rich glycoprotein, apolipoproteins, and albumin, are described in relation to their role in NP detection by immune cells. Particular emphasis is placed on their role in mediating the interaction of NPs with innate and adaptive immune cells. Finally, strategies to reduce PC formation are discussed in detail.

In Vivo Applications of Molecularly Imprinted Polymers for Drug Delivery: A Pharmaceutical Perspective

Molecularly imprinted polymers (MIPs) have been proven to be a promising candidate for drug delivery systems (DDS) due to their ability to provide a sustained and controlled drug release, making them useful for treating a wide range of medical conditions. MIP-based DDS offer many advantages, including the administration of a smaller drug doses, due to the higher drug payload or targeted delivery, resulting in fewer side effects, as well as the possibility of attaining high concentrations of the drug in the targeted tissues. Whether designed as drug reservoirs or targeted DDS, MIPs are of great value to drug delivery as conventional drug formulations can be redesigned as DDS to overcome the active pharmaceutical ingredient's (APIs) poor bioavailability, toxic effects, or other shortcomings that previously made them less efficient or unsuitable for therapy. Therefore, MIP design could be a promising alternative to the challenging research and development of new lead compounds. Research on MIPs is primarily conducted from a material science perspective, which often overlooks some of their key pharmaceutical requirements. In this review, we emphasize the specific features that make MIPs suitable for clinical use, from both a material science and a biopharmaceutical perspective.

Mimicking Pseudo-Virion Interactions with Abiotic Surfaces: Deposition of Polymer Nanoparticles with Albumin Corona

Adsorption of human serum albumin (HSA) molecules on negatively charged polystyrene microparticles was studied using the dynamic light scattering, the electrophoretic and the solution depletion methods involving atomic force microscopy. Initially, the physicochemical characteristics of the albumin comprising the hydrodynamic diameter, the zeta potential and the isoelectric point were determined as a function of pH. Analogous characteristics of the polymer particles were acquired, including their size and zeta potential. The formation of albumin corona on the particles was investigated in situ by electrophoretic mobility measurements. The size, stability and electrokinetic properties of the particles with the corona were also determined. The particle diameter was equal to 125 nm, which coincides with the size of the SARS-CoV-2 virion. The isoelectric point of the particles appeared at a pH of 5. The deposition kinetics of the particles was determined by atomic force microscopy (AFM) under diffusion and by quartz microbalance (QCM) under flow conditions. It was shown that the deposition rate at a gold sensor abruptly vanished with pH following the decrease in the zeta potential of the particles. It is postulated that the acquired results can be used as useful reference systems mimicking virus adsorption on abiotic surfaces.

Biopolymeric nanocarrier: an auspicious system for oral delivery of insulin

Subcutaneous administration of insulin has been practiced for the clinical supervision of diabetes pathogenesis but it is often ineffective to imitate the glucose homeostasis and is always invasive. Therefore, it causes patient discomfort and infection of local tissue. These issues lead to finding an alternative route for insulin delivery that could be effective, promising, and non-invasive. However, delivery of insulin orally is the most suitable route but the rapid breakdown of insulin by the gastrointestinal enzymes becomes a major barrier to this method. Therefore, nanocarriers (which guard insulin against degradation and facilitate its uptake) are preferred for oral insulin delivery. Among various categories of nanocarriers, bio-polymeric nanocarriers draw special attention owing to their hydrophilic, non-toxic, and biodegradable nature. This review provides a detailed overview of insulin-loaded biopolymer-based nanocarriers, which give future direction in the optimization and development of a clinically functional formulation for their effective and safe delivery.

How Nanoparticles Open the Paracellular Route of Biological Barriers: Mechanisms, Applications, and Prospects

Biological barriers are essential physiological protective systems and obstacles to drug delivery. Nanoparticles (NPs) can access the paracellular route of biological barriers, either causing adverse health impacts on humans or producing therapeutic opportunities. This Review introduces the structural and functional influences of NPs on the key components that govern the paracellular route, mainly tight junctions, adherens junctions, and cytoskeletons. Furthermore, we evaluate their interaction mechanisms and address the influencing factors that determine the ability of NPs to open the paracellular route, which provides a better knowledge of how NPs can open the paracellular route in a safer and more controllable way. Finally, we summarize limitations in the research models and methodologies of the existing research in the field and provide future research direction. This Review demonstrates the in-depth causes for the reversible opening or destruction of the integrity of barriers generated by NPs; more importantly, it contributes insights into the design of NP-based medications to boost paracellular drug delivery efficiency.

Quantitative comparison of the protein corona of nanoparticles with different matrices

Nanoparticles (NPs) are paving the way for improved treatments for difficult to treat diseases diseases; however, much is unknown about their fate in the body. One important factor is the interaction between NPs and blood proteins leading to the formation known as the “protein corona” (PC). The PC, consisting of the Hard (HC) and Soft Corona (SC), varies greatly based on the NP composition, size, and surface properties. This highlights the need for specific studies to differentiate the PC formation for each individual NP system. This work focused on comparing the HC and SC of three NPs with different matrix compositions: a) polymeric NPs based on poly(lactic-co-glycolic) acid (PLGA), b) hybrid NPs consisting of PLGA and Cholesterol, and c) lipidic NPs made only of Cholesterol. NPs were formulated and characterized for their physico-chemical characteristics and composition, and then were incubated in human plasma. In-depth purification, identification, and statistical analysis were then performed to identify the HC and SC components. Finally, similar investigations demonstrated whether the presence of a targeting ligand on the NP surface would affect the PC makeup. These results highlighted the different PC fingerprints of these NPs, which will be critical to better understand the biological influences of the PC and improve future NP designs.

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NPs with different matrices were formulated: PLGA, Cholesterol, or mixed PLGA-Chol hybrids.

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The hard and soft corona of each formulation was quantified and compared.

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The PC seems to be more strongly affected by the polymer rather than the lipid in mixed NPs.

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The soft corona depends more on the hard corona composition than on the matrix.

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Surface modification with a targeting ligand did not influence PC composition.