Surface chemistry-mediated modulation of adsorbed albumin folding state specifies nanocarrier clearance by distinct macrophage subsets

Glycosylation-driven interactions of nanoparticles with the extracellular matrix: Implications for inflammation and drug delivery

Cationic nanoparticles (NPs) are emerging as promising carriers for intra-articular drug delivery, particularly for osteoarthritis (OA) where treatment options are limited. However, the clinical translation is challenged by an incomplete understanding of NP interactions within pathological environments. While the influence of the protein coronas on NP behavior has been extensively studied, the specific role of glycoproteins in the extracellular matrix (ECM) remains underexplored, representing a significant knowledge gap. This study investigates how glycosylation-driven interactions between polymeric NPs and enzyme-degraded cartilage biomolecules such as glycosaminoglycans (GAGs) affect NP-ECM aggregate formation and subsequent inflammatory responses. Using an ex vivo model of cartilage degradation induced by catabolic enzymes- hyaluronidase, ADAMTS5 and collagenase- a novel model system was developed to specifically study the behavior of small (<10 nm) and large (∼270 nm) cationic NPs in glycoprotein-enriched environments. Atomic force microscopy and dynamic light scattering revealed distinct mesh-like structures formed by the NP aggregates following different enzymatic treatments, confirming the adsorption of glycosylated fragments onto the particles. While total protein content showed minimal differences between NP samples, smaller NPs demonstrated a prominent association with GAGs such as hyaluronic acid and aggrecan, as demonstrated by circular dichroism. These ECM-NP interactions significantly influenced the immunological response, as evidenced by differential cytokine production from macrophages exposed to the aggregates. Our findings underscore the crucial, yet underappreciated, role of glycoproteins in determining NP behavior in pathological environments. Accounting for glycoprotein interactions into the design of nanomaterial and drug delivery systems could significantly improve therapeutic outcomes by enhanced targeting precision, optimized delivery, and effectively modulating immune responses in OA and other complex diseases.

Protein-Nonfouling and Cell-Binding Polysulfobetaine Inducing Fast Transcytosis for Tumor-Active Drug Delivery

Long blood circulation and fast cellular uptake are essential yet paradoxical requirements for efficient tumor-targeted drug delivery carriers. For instance, polyzwitterions, generally nonfouling to proteins and cells, have been extensively explored as long-circulating drug delivery carriers but suffer ultraslow cell internalization, making them inefficient in delivering drugs to cells. Protein-resistant yet cell membrane-binding polymers will simultaneously achieve long blood circulation and fast cellular internalization, but their designs are generally complicated, such as introducing cell-membrane binding groups. Here, it is shown that the N-alkyl chain length of zwitterionic poly(sulfobetaine) can be used to tune its affinity toward proteins and cell membranes. A poly(sulfobetaine) with a moderately long N-alkyl chain became cell membrane-philic while retaining protein resistance, leading to long blood circulation and fast cellular uptake, which further triggered efficient tumor cell transcytosis and intratumor penetration. Thus, its paclitaxel (PTX)-loaded micelles demonstrated potent antitumor efficacy in triple-negative breast cancer models. This study showcases a paradigm of designing polyzwitterions harmonizing long blood circulation and fast cellular uptake properties as tumor-active drug delivery carriers.

Efficacy of benznidazole delivery during Chagas disease nanotherapy is dependent on the nanocarrier morphology

The causative agent of Chagas disease, the protozoan Trypanosoma cruzi, is an obligate intracellular parasite that is typically treated with daily oral administration of Benznidazole (BNZ), a parasiticidal pro-drug with considerable side effects. Previously, we effectively targeted intracellular parasites using ∼100 nm diameter BNZ-loaded poly(ethylene glycol)-b-poly(propylene sulfide) (PEG-b-PPS) vesicular nanocarriers (a.k.a. polymersomes) in a T. cruzi-infected mouse model, without causing the typical side effects associated with standard BNZ treatment. Here, we exploit the structural versatility of the PEG-b-PPS system to investigate the impact of nanocarrier structure on the efficacy of BNZ nanotherapy. Despite sharing the same surface chemistry and oxidation-sensitive biodegradation, solid core ∼25 nm PEG-b-PPS micelles failed to produce in vivo trypanocidal effects. By applying the Förster Resonance Energy Transfer strategy, we demonstrated that PEG-b-PPS polymersomes promoted sustained intracellular drug release and enhanced tissue accumulation, offering a significant advantage for intracellular drug delivery compared to micelles with the same surface chemistry. Our studies further revealed that the lack of parasiticidal effect in PEG-b-PPS micelles is likely due to their slower rate of accumulation into solid tissues, consistent with the prolonged circulation time of intact micelles. Considering the cardiac damage typically induced by T. cruzi infection, this study also investigated the contributions of cardiac cellular biodistribution and payload release for both nanocarriers to the treatment outcomes of BNZ delivery. Our findings emphasize the crucial role of cardiac macrophages in the parasiticidal effect of BNZ formulations and highlight the critical importance of nanobiomaterial structure during therapeutic delivery.

Cyclooxygenase-2/prostaglandin E2 inhibition remodulated photodynamic therapy-associated immunosuppression for enhanced cancer immunotherapy

Low immunogenicity and immunosuppressive tumor microenvironment (TME) are two pivotal factors restricting tumor immunotherapy. Photodynamic therapy (PDT) directly destroys cancer cells by producing reactive oxygen species (ROS), and enhances the immunogenicity of "cold" tumors by inducing immunogenic cell death (ICD), thereby promoting T cell development against tumors. However, PDT also deteriorates immunosuppression through overactivating the cyclooxygenase-2/prostaglandin E2 (COX-2/PGE2) pathway. To this end, biocompatible albumin nanoassemblies co-delivering IR780 and diclofenac are herein developed for enhanced therapy against triple-negative breast cancer. PDT-exacerbated PGE2 overexpression is effectively abolished by diclofenac-mediated COX-2 inhibition, which reprograms immunosuppressive TME via downregulating the infiltration of various immunosuppressive cells and their cytokine secretion to enhance effector T cell infiltration. Consequently, the enhanced antitumor immunity effectively inhibits tumor growth, prevents the recurrency and metastasis, and remarkably boosts the treatment efficacy of PD-L1 blockade. This study sets an intriguing example for overcoming the COX-2/PGE2 pathway-exacerbated immunosuppression alongside immune activation, thus enhancing synergistic cancer immunotherapy potentiated by various ROS-producing therapies (e.g., PDT and radiotherapy) and chemotherapy.

Exploring Nano-Delivery Systems to Enhance the Edaravone Performance in Amyotrophic Lateral Sclerosis Treatment

Edaravone is one of the treatment options for Amyotrophic Lateral Sclerosis, but its therapeutic efficacy is limited due to the incapacity to cross the blood-brain barrier, as well as its short life span and poor stability, which is ultimately caused by its tautomerism in physiological condions. This work presents an overview about the use of several nanoformulations based on polymeric, protein, lipidic, or hybrid structure as suitable and stable drug delivery systems for encapsulating edaravone. We also evaluated the functionalization of nanoparticles with pegylated chains using the polyethylene glycol or tocopherol polyethylene glycol succinate and the possibility of preparing polymeric nanoparticles at different pH (7.4, 9, and 11). Edaravone was sucessfully encapsulated in polymeric, lipid-polymer hybrid, and lipidic nanoparticles. The use of higher pH values in the synthesis of polymeric nanoparticles has led to a decrease in nanoparticle size and an increase in the percentage of encapsulation efficiency. However, the resulting nanoformulations are not stable. Only polymeric and hybrid nanoparticles showed good stability over 80 days of storage, mainly at 4 °C. Overall, the nanoformulations tested did not show cytotoxicity in the SH-SY5Y cell line except the nanostructured lipid carrier formulations that showed some cytotoxicity possibly due to lipidic peroxidation. In conclusion, this work shows that edaravone can be encapsulated in different nanocarriers that could act as an interesting alternative for the treatment of Amyotrophic Lateral Sclerosis.

Engineering the physical characteristics of biomaterials for innate immune-mediated cancer immunotherapy

It has recently been recognized that the physical characteristics of biomaterials - such as size, structure, shape, charge, mechanical strength, hydrophobicity, and multivalency - regulate immunological functions in innate immune cells. In immuno-oncology applications, biomaterials are engineered with distinct physical properties to achieve desired innate immune responses. In this review, we discuss how physical characteristics influence effector functions and innate immune signaling pathways in distinct innate immune cell subtypes. We highlight how physical properties of biomaterials impact phagocytosis regulation, biodistribution, and innate immune cell targeting. We outline the recent advances in physical engineering of biomaterials that directly or indirectly induce desired innate immune responses for cancer immunotherapy. Lastly, we discuss the challenges in current biomaterial approaches that need to be addressed to improve clinical applicability.

Defining Structure-Function Relationships of Amphiphilic Excipients Enables Rational Design of Ultra-Stable Biopharmaceuticals

Biopharmaceuticals are the fastest-growing class of drugs in the healthcare industry, but their global reach is severely limited by their propensity for rapid aggregation. Currently, surfactant excipients such as polysorbates and poloxamers are used to prevent protein aggregation, which significantly extends shelf-life. Unfortunately, these excipients are themselves unstable, oxidizing rapidly into 100s of distinct compounds, some of which cause severe adverse events in patients. Here, the highly stable, well-defined, and modular nature of amphiphilic polyacrylamide-derived excipients is leveraged to isolate the key mechanisms responsible for excipient-mediated protein stabilization. With a library of compositionally identical but structurally distinct amphiphilic excipients, a new property is quantified, compositional dispersity, that is key to excipient performance and utilized this property to rationally design new ultra-stable surfactant excipients that increase the stability of a notoriously unstable biopharmaceutical, monomeric insulin, by an order of magnitude. This comprehensive and generalizable understanding of excipient structure-function relationships represents a paradigm shift for the formulation of biopharmaceuticals, moving away from trial-and-error screening approaches toward rational design.

Unlocking Transplant Tolerance with Biomaterials

For patients suffering from organ failure due to injury or autoimmune disease, allogeneic organ transplantation with chronic immunosuppression is considered the god standard in terms of clinical treatment. However, the true "holy grail" of transplant immunology is operational tolerance, in which the recipient exhibits a sustained lack of alloreactivity toward unencountered antigen presented by the donor graft. This outcome is resultant from critical changes to the phenotype and genotype of the immune repertoire predicated by the activation of specific signaling pathways responsive to soluble and mechanosensitive cues. Biomaterials have emerged as a medium for interfacing with and reprogramming these endogenous pathways toward tolerance in precise, minimally invasive, and spatiotemporally defined manners. By viewing seminal and contemporary breakthroughs in transplant tolerance induction through the lens of biomaterials-mediated immunomodulation strategies-which include intrinsic material immunogenicity, the depot effect, graft coatings, induction and delivery of tolerogenic immune cells, biomimicry of tolerogenic immune cells, and in situ reprogramming-this review emphasizes the stunning diversity of approaches in the field and spotlights exciting future directions for research to come.

Zwitterionic Poly(ethylene glycol) Nanoparticles Minimize Protein Adsorption and Immunogenicity for Improved Biological Fate

We report the assembly of poly(ethylene glycol) nanoparticles (PEG NPs) and optimize their surface chemistry to minimize the formation of protein coronas and immunogenicity for improved biodistribution. PEG NPs cross-linked with disulfide bonds are synthesized utilizing zeolitic imidazolate framework-8 NPs as the templates, which are subsequently modified with PEG molecules with different end groups (carboxyl, methoxy, or amino) to vary the surface chemistry. Among the modifications, the amino and residual carboxyl groups form a pair of zwitterionic structures on the surface of PEG NPs, which minimize the adsorption of proteins (e.g., immunoglobulin, complement proteins) and maximize the blood circulation time. The influence of preexisting PEG antibodies in mice on the pharmacokinetics of zwitterionic PEG NPs is negligible, which demonstrates the resistance of anti-PEG antibodies and inhibition of the accelerated blood clearance phenomenon. This research highlights the importance of the surface chemistry of PEGylated NPs in the design of delivery systems and reveals their translational potential for cancer therapy.

Specific surface-modified iron oxide nanoparticles trigger complement-dependent innate and adaptive antileukaemia immunity

Considerable advances have been achieved in the application of nanomaterials for immunotherapies, yet the precise immune effects induced by protein corona remain elusive. Here, we explore the formation mechanism and immune regulation process of protein corona in acute myeloid leukaemia (AML) mouse models using commercialized iron oxide nanoparticles (IONPs), with different surface modifications, including an FDA-approved variant. Using macrophages depleted or Complement Component 3 (C3) knockout mice, we demonstrate that carboxymethyl dextran-coated IONP (IONP-COOH) reduces leukaemia burden. Mechanistically, IONP-COOH indirectly binds to C3b after activating the complement alternative pathway, subsequently enhancing phagocytosis of macrophages and activating adaptive immunity mediated by complement corona. While aminated dextran-coated IONPs directly absorb C3b and activate the lectin pathway, leading to immune cell exhaustion. Our findings suggest that IONP-COOH may serve as an immune activator for AML treatment, offering a promising approach to developing therapeutic nanomaterials by leveraging surface chemistry to enhance immunotherapy.

The role of patient-specific variables in protein corona formation and therapeutic efficacy in nanomedicine

Despite their potential, the adoption of nanotechnology in therapeutics remains limited, with only around eighty nanomedicines approved in the past 30 years. This disparity is partly due to the "one-size-fits-all" approach in medical design, which often overlooks patient-specific variables such as biological sex, genetic ancestry, disease state, environment, and age that influence nanoparticle behavior. Nanoparticles (NPs) must be transported through systemic, microenvironmental, and cellular barriers that vary across heterogeneous patient populations. Key patient-dependent properties impacting NP delivery include blood flow rates, body fat distribution, reproductive organ vascularization, hormone and protein levels, immune responses, and chromosomal differences. Understanding these variables is crucial for developing effective, patient-specific nanotechnologies. The formation of a protein corona around NPs upon exposure to biological fluids significantly alters NP properties, affecting biodistribution, pharmacokinetics, cytotoxicity, and organ targeting. The dynamics of the protein corona, such as time-dependent composition and formation of soft and hard coronas, depend on NP characteristics and patient-specific serum components. This review highlights the importance of understanding protein corona formation across different patient backgrounds and its implications for NP design, including sex, ancestry, age, environment, and disease state. By exploring these variables, we aim to advance the development of personalized nanomedicine, improving therapeutic efficacy and patient outcomes.

Innate immunity-modulating nanobiomaterials for controlling inflammation resolution

The acute inflammatory response is an inherent protective mechanism, its unsuccessful resolution can contribute to disease pathogenesis and potentially lead to death. Innate immune cells are the first line of host defenders and play a substantial role in inflammation initiation, amplification, resolution, or subsequent disease progression. As the resolution of inflammation is an active and highly regulated process, modulating innate immune cells, including neutrophils, monocytes and macrophages, and endothelial cells, and their interactions offer opportunities to control excessive inflammation. Nanobiomaterials have shown superior therapeutic potential in inflammation-related diseases by manipulating inflammatory responses because nanobiomaterials can target and interact with innate immune cells. Versatile nanobiomaterials can be designed for targeted modulation of specific innate immune responses. Nanopro-resolving medicines have been prepared both with pro-resolving lipid mediators and peptides each demonstrated to active resolution of inflammation in animal disease models. Here, we review innovative nanobiomaterials for modulating innate immunity and alleviating inflammation. We summarise the strategies converging the design of nanobiomaterials and the nano-bio interaction in modulating innate immune profiles and propelling the advancement of nanobiomaterials for inflammatory disease treatments. We also propose the future perspectives and translational challenges of nanobiomaterials that need to be overcome in this swiftly rising field.

Nanoparticle-assisted Targeting Delivery Technologies for Preventing Organ Rejection

Although organ transplantation is a life-saving medical procedure, the challenge of posttransplant rejection necessitates safe and effective immune modulation strategies. Nanodelivery approaches may have the potential to overcome the limitations of small-molecule immunosuppressive drugs, achieving efficacious treatment options for transplant tolerance without compromising overall host immunity. This review highlights recent advances in biomaterial-assisted formulations and technologies for targeted nanodrug delivery with transplant organ- or immune cell-level precision for treating graft rejection after transplantation. We provide an overview of the mechanism of transplantation rejection, current clinically approved immunosuppressive drugs, and their relevant limitations. Finally, we discuss the targeting principles and advantages of organ- and immune cell-specific delivery technologies. The development of biomaterial-assisted novel therapeutic strategies holds considerable promise for treating organ rejection and clinical translation.

Stereoselective Interactions of Chiral Polyurea Nanocapsules with Albumins

Exploiting the chirality of nanometric structures to modulate biological systems is an emerging and compelling area of research. In this study, we reveal that chiral polyurea nanocapsules exhibit significant stereoselective interactions with albumins from various sources despite their nearly neutral surface potential. Moreover, these interactions can be modulated by altering the nanocapsule surface composition, offering new opportunities to impact their distribution and, if used as a drug delivery system, the pharmacokinetics of the drug. Notably, these interactions promote preferential cellular internalization of only one chiral configuration. We synthesized chiral polyurea nanocapsules with reproducible sizes via interfacial polymerization between toluene 2,4-diisocyanate and d- or l-lysine enantiomers on a volatile oil-in-water emulsion interface, followed by solvent evaporation. Further synthesis optimization reduced the capsule size to a range compatible with in vivo administration, and capsules with alternating chiral patterns were also produced. The stereoselective interactions with albumins were assessed through capsule size changes, fluorescence quenching, and surface charge measurements. Biocompatibility, stability, and cellular internalization were evaluated. Additionally, scanning transmission electron and atomic force microscopy were carried out to assess the capsule shape, surface composition, and morphology. We discovered that d-nanocapsules exhibited 2.1-2.6 times greater albumin adsorption compared with their l-counterparts. This difference is attributed to the distinct morphology of d-nanocapsules, characterized by a more concave shape, central depression, and rougher surface. The extent of adsorption could be finely tuned by adjusting the d- and l-lysine monomer ratios during synthesis. Both chiral configurations demonstrated biocompatibility and stability with d-nanocapsules showing a 2.5-fold increase in cellular internalization.

Pegylated gold nanoparticles interact with lipid bilayer and human serum albumin and transferrin

Gold nanoparticles (AuNPs) are potentially applicable in drug/nucleic acid delivery systems. Low toxicity, high stability, and bioavailability are crucial for the therapeutic use of AuNPs and they are mainly determined by their interactions with proteins and lipids on their route to the target cells. In this work, we investigated the interaction of two pegylated gold nanoparticles, AuNP14a and AuNP14b, with human serum proteins albumin (HSA) and transferrin (Tf) as well as dimyristoyl-phosphatidylcholine (DMPC) liposomes, which can be a representative of biomembranes. We showed that AuNP14a/b interacted with HSA and Tf changing their electrical, thermodynamic, and structural properties as evidenced by dynamic light scattering, zeta potential, transmission electron microscopy, circular dichroism, fluorescence quenching, and isothermal titration calorimetry. These nanoparticles penetrated the DMPC membrane suggesting their ability to reach a target inside the cell. In most of the effects, AuNP14b was more effective than AuNP14a, which might result from its more positive charge. Further studies are needed to evaluate whether the interaction of AuNP14a/b with HSA and Tf is safe for the cell/organism and whether they may safely penetrate natural membranes.

Streamlined Formation and Manipulation of Charged Polymersomes

Charged polymersomes are attractive for advanced material applications due to their versatile encapsulation capabilities and charge-induced functionality. Although desirable, the pH-sensitivity of charged block copolymers adds complexity to its self-assembly process, making it challenging to produce charged polymersomes in a reliable manner. In this work, a flow approach to control and strike a delicate balance between solvent composition and pH for self-assembly is used. This allows for the identification of a phase window to reliably produce of charged polymersomes. The utility of this approach to streamline downstream processes, such as morphological transformation or in-line purification is further demonstrated. As proof-of-concept, it is shown that the processed polymersomes can be used for surface modifications facilitated by charge complexation.

Unveiling the Performance of Co-Assembled Hybrid Nanocarriers: Moving towards the Formation of a Multifunctional Lipid/Random Copolymer Nanoplatform

Despite the appealing properties of random copolymers, the use of these biomaterials in association with phospholipids is still limited, as several aspects of their performance have not been investigated. The aim of this work is the formulation of lipid/random copolymer platforms and the comprehensive study of their features by multiple advanced characterization techniques. Both biomaterials are amphiphilic, including two phospholipids (1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and a statistical copolymer of oligo (ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(diisopropylamino) ethyl methacrylate (DIPAEMA). We examined the design parameters, including the lipid composition, the % comonomer ratio, and the lipid-to-polymer ratio that could be critical for their behavior. The structures were also probed in different conditions. To the best of the authors' knowledge, this is the first time that P(OEGMA-co-DIPAEMA)/lipid hybrid colloidal dispersions have been investigated from a membrane mechanics, biophysical, and morphological perspective. Among other parameters, the copolymer architecture and the hydrophilic to hydrophobic balance are deemed fundamental parameters for the biomaterial co-assembly, having an impact on the membrane's fluidity, morphology, and thermodynamics. Exploiting their unique characteristics, the most promising candidates were utilized for methotrexate (MTX) loading to explore their encapsulation capability and potential antitumor efficacy in vitro in various cell lines.

Protein Corona-Directed Cellular Recognition and Uptake of Polyethylene Nanoplastics by Macrophages

The widespread use of plastic products in daily life has raised concerns about the health hazards associated with nanoplastics (NPs). When exposed, NPs are likely to infiltrate the bloodstream, interact with plasma proteins, and trigger macrophage recognition and clearance. In this study, we focused on establishing a correlation between the unique protein coronal signatures of high-density (HDPE) and low-density (LDPE) polyethylene (PE) NPs with their ultimate impact on macrophage recognition and cytotoxicity. We observed that low-density and high-density lipoprotein receptors (LDLR and SR-B1), facilitated by apolipoproteins, played an essential role in PE-NP recognition. Consequently, PE-NPs activated the caspase-3/GSDME pathway and ultimately led to pyroptosis. Advanced imaging techniques, including label-free scattered light confocal imaging and cryo-soft X-ray transmission microscopy with 3D-tomographic reconstruction (nano-CT), provided powerful insights into visualizing NPs-cell interactions. These findings underscore the potential risks of NPs to macrophages and introduce analytical methods for studying the behavior of NPs in biological systems.

Effect of Nanoparticle Curvature on Its Interaction with Serum Proteins

The size or the curvature of nanoparticles (NPs) plays an important role in regulating the composition of the protein corona. However, the molecular mechanisms of how curvature affects the interaction of NPs with serum proteins still remain elusive. In this study, we employ all-atom molecular dynamics simulations to investigate the interactions between two typical serum proteins and PEGylated Au NPs with three different surface curvatures (0, 0.1, and 0.5 nm-1, respectively). The results show that for proteins with a regular shape, the binding strength between the serum protein and Au NPs decreases with increasing curvature. For irregularly shaped proteins with noticeable grooves, the binding strength between the protein and Au NPs does not change obviously with increasing curvature in the cases of smaller curvature. However, as the curvature continues to increase, Au NPs may act as ligands firmly adsorbed in the protein grooves, significantly enhancing the binding strength. Overall, our findings suggest that the impact of NP curvature on protein adsorption may be nonmonotonic, which may provide useful guidelines for better design of functionalized NPs in biomedical applications.

Applications of Microbial Organophosphate-Degrading Enzymes to Detoxification of Organophosphorous Compounds for Medical Countermeasures against Poisoning and Environmental Remediation

Mining of organophosphorous (OPs)-degrading bacterial enzymes in collections of known bacterial strains and in natural biotopes are important research fields that lead to the isolation of novel OP-degrading enzymes. Then, implementation of strategies and methods of protein engineering and nanobiotechnology allow large-scale production of enzymes, displaying improved catalytic properties for medical uses and protection of the environment. For medical applications, the enzyme formulations must be stable in the bloodstream and upon storage and not susceptible to induce iatrogenic effects. This, in particular, includes the nanoencapsulation of bioscavengers of bacterial origin. In the application field of bioremediation, these enzymes play a crucial role in environmental cleanup by initiating the degradation of OPs, such as pesticides, in contaminated environments. In microbial cell configuration, these enzymes can break down chemical bonds of OPs and usually convert them into less toxic metabolites through a biotransformation process or contribute to their complete mineralization. In their purified state, they exhibit higher pollutant degradation efficiencies and the ability to operate under different environmental conditions. Thus, this review provides a clear overview of the current knowledge about applications of OP-reacting enzymes. It presents research works focusing on the use of these enzymes in various bioremediation strategies to mitigate environmental pollution and in medicine as alternative therapeutic means against OP poisoning.

Lung-selective nucleic acid vectors generated by in vivo lung-targeting-protein decoration of polyplexes

Nucleic acid drugs show immense therapeutic potential, but achieving selective organ targeting (SORT) for pulmonary disease therapy remains a formidable challenge due to the high mortality rate caused by pulmonary embolism via intravenous administration or the mucus barrier in the respiratory tract via nebulized delivery. To meet this important challenge, we propose a new strategy to prepare lung-selective nucleic-acid vectors generated by in vivo decoration of lung-targeting proteins on bioreducible polyplexes. First, we synthesized polyamidoamines, named pabol and polylipo, to encapsulate and protect nucleic acids, forming polyamidoamines/mRNA polyplexes. Second, bovine serum albumin (BSA) was coated on the surface of these polyplexes, called BSA@polyplexes, including BSA@pabol polyplexes and BSA@polylipo polyplexes, to neutralize excess positive charge, thereby enhancing biosafety. Finally, after subcutaneous injection, proteins, especially vitronectin and fibronectins, attached to the polyplexes, resulting in the formation of lung-selective nucleic-acid vectors that achieve efficient lung targeting.

STING agonist-conjugated metal-organic framework induces artificial leukocytoid structures and immune hotspots for systemic antitumor responses

Radiotherapy is widely used for cancer treatment, but its clinical utility is limited by radioresistance and its inability to target metastases. Nanoscale metal-organic frameworks (MOFs) have shown promise as high-Z nanoradiosensitizers to enhance radiotherapy and induce immunostimulatory regulation of the tumor microenvironment. We hypothesized that MOFs could deliver small-molecule therapeutics to synergize with radiotherapy for enhanced antitumor efficacy. Herein, we develop a robust nanoradiosensitizer, GA-MOF, by conjugating a STING agonist, 2',3'-cyclic guanosine monophosphate-adenosine monophosphate (GA), on MOFs for synergistic radiosensitization and STING activation. GA-MOF demonstrated strong anticancer efficacy by forming immune-cell-rich nodules (artificial leukocytoid structures) and transforming them into immunostimulatory hotspots with radiotherapy. Further combination with an immune checkpoint blockade suppressed distant tumors through systemic immune activation. Our work not only demonstrates the potent radiosensitization of GA-MOF, but also provides detailed mechanisms regarding MOF distribution, immune regulatory pathways and long-term immune effects.

Alginate nanogel-embedded liposomal drug carriers facilitate drug delivery efficiency in arthritis treatment

Despite numerous advantages of liposomes in treating rheumatoid arthritis (RA), the in vivo stability remains a critical issue. Current strategies for improving liposomal stability often compromise their original properties. Herein, we designed an alginate nanogel-embedded liposome aiming at retaining those inherent advantages while enhancing their in vivo stability. The introduction of alginate network within the liposome core can provide mechanical support and controlled drug release without affecting the surface properties. Results showed the cross-linking of alginate network within the inner core of liposomes elevated the particle rigidity to 3 times, allowing for improved stability and decreased drug leakage. Moreover, this nanogel-embedded liposome with optimized elasticity obviously facilitated cellular uptake in inflammatory macrophages. When entering blood circulation, increased rigidity altered the composition of protein corona on the particle surface, resulting in 2-fold increase in circulation time and improved drug accumulation in arthritic joints. When anti-inflammatory chlorogenic acid (CA) was encapsulated into the nanogel network, this CA-loaded nanogel-embedded liposome significantly inhibited ROS production and inflammatory response, ultimately achieved superior therapeutic outcome in arthritic rats. Results demonstrated that this nanogel-embedded liposomes can essentially retain the inherent advantages and overcome the drawbacks of liposomes, thereby improving the drug delivery efficiency.

Deciphering the Lipid-Random Copolymer Interactions and Encoding Their Properties to Design a Hybrid System

Lipid/copolymer colloidal systems are deemed hybrid materials with unique properties and functionalities. Their hybrid nature leads to complex interfacial phenomena, which have not been fully encoded yet, navigating their properties. Moving toward in-depth knowledge of such systems, a comprehensive investigation of them is imperative. In the present study, hybrid lipid/copolymer structures were fabricated and examined by a gamut of techniques, including dynamic light scattering, fluorescence spectroscopy, cryogenic transmission electron microscopy, microcalorimetry, and high-resolution ultrasound spectroscopy. The biomaterials that were mixed for this purpose at different ratios were 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine and four different linear, statistical (random) amphiphilic copolymers, consisting of oligo(ethylene glycol) methyl ether methacrylate as the hydrophilic comonomer and lauryl methacrylate as the hydrophobic one. The colloidal dispersions were studied for lipid/copolymer interactions regarding their physicochemical, morphological, and biophysical behavior. Their membrane properties and interactions with serum proteins were also studied. The aforementioned techniques confirmed the hybrid nature of the systems and the location of the copolymer in the structure. More importantly, the random architecture of the copolymers, the hydrophobic-to-hydrophilic balance of the nanoplatforms, and the lipid-to-polymer ratio are highlighted as the main design-influencing factors. Elucidating the lipid/copolymer interactions would contribute to the translation of hybrid nanoparticle performance and, thus, their rational design for multiple applications, including drug delivery.

Programable Albumin-Hitchhiking Nanobodies Enhance the Delivery of STING Agonists to Potentiate Cancer Immunotherapy

Stimulator of interferon genes (STING) is a promising target for potentiating antitumor immunity, but multiple pharmacological barriers limit the clinical utility, efficacy, and/or safety of STING agonists. Here we describe a modular platform for systemic administration of STING agonists based on nanobodies engineered for in situ hitchhiking of agonist cargo on serum albumin. Using site-selective bioconjugation chemistries to produce molecularly defined products, we found that covalent conjugation of a STING agonist to anti-albumin nanobodies improved pharmacokinetics and increased cargo accumulation in tumor tissue, stimulating innate immune programs that increased the infiltration of activated natural killer cells and T cells, which potently inhibited tumor growth in multiple mouse tumor models. We also demonstrated the programmability of the platform through the recombinant integration of a second nanobody domain that targeted programmed cell death ligand-1 (PD-L1), which further increased cargo delivery to tumor sites while also blocking immunosuppressive PD-1/PD-L1 interactions. This bivalent nanobody carrier for covalently conjugated STING agonists stimulated robust antigen-specific T cell responses and long-lasting immunological memory, conferred enhanced therapeutic efficacy, and was effective as a neoadjuvant treatment for improving responses to adoptive T cell transfer therapy. Albumin-hitchhiking nanobodies thus offer an enabling, multimodal, and programmable platform for systemic delivery of STING agonists with potential to augment responses to multiple immunotherapeutic modalities.

Controlled adsorption of multiple bioactive proteins enables targeted mast cell nanotherapy

Protein adsorption onto nanomaterials often results in denaturation and loss of bioactivity. Controlling the adsorption process to maintain the protein structure and function has potential for a range of applications. Here we report that self-assembled poly(propylene sulfone) (PPSU) nanoparticles support the controlled formation of multicomponent enzyme and antibody coatings and maintain their bioactivity. Simulations indicate that hydrophobic patches on protein surfaces induce a site-specific dipole relaxation of PPSU assemblies to non-covalently anchor the proteins without disrupting the protein hydrogen bonding or structure. As a proof of concept, a nanotherapy employing multiple mast-cell-targeted antibodies for preventing anaphylaxis is demonstrated in a humanized mouse model. PPSU nanoparticles displaying an optimized ratio of co-adsorbed anti-Siglec-6 and anti-FcεRIα antibodies effectively inhibit mast cell activation and degranulation, preventing anaphylaxis. Protein immobilization on PPSU surfaces provides a simple and rapid platform for the development of targeted protein nanomedicines.

A Biomimetic Multi-Component Subunit Vaccine via Ratiometric Loading of Hierarchical Hydrogels

The development of subunit vaccines that mimic the molecular complexity of attenuated vaccines has been limited by the difficulty of intracellular co-delivery of multiple chemically diverse payloads at controllable concentrations. We report on hierarchical hydrogel depots employing simple poly(propylene sulfone) homopolymers to enable ratiometric loading of a protein antigen and four physicochemically distinct adjuvants in a hierarchical manner. The optimized vaccine consisted of immunostimulants either adsorbed to or encapsulated within nanogels, which were capable of noncovalent anchoring to subcutaneous tissues. These 5-component nanogel vaccines demonstrated enhanced humoral and cell-mediated immune responses compared to formulations with standard single adjuvant and antigen pairing. The use of a single simple homopolymer capable of rapid and stable loading and intracellular delivery of diverse molecular cargoes holds promise for facile development and optimization of scalable subunit vaccines and complex therapeutic formulations for a wide range of biomedical applications.

Impact of Lipid Composition on Vesicle Protein Adsorption: A BSA Case Study

Investigating the interaction between liposomes and proteins is of paramount importance in the development of liposomal formulations with real potential for bench-to-bedside transfer. Upon entering the body, proteins are immediately adsorbed on the liposomal surface, changing the nanovehicles' biological identity, which has a significant impact on their biodistribution and pharmacokinetics and ultimately on their therapeutic effect. Albumin is the most abundant plasma protein and thus usually adsorbs immediately on the liposomal surface. We herein report a comprehensive investigation on the adsorption of model protein bovine serum albumin (BSA) onto liposomal vesicles containing the zwitterionic lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), in combination with either cholesterol (CHOL) or the cationic lipid 1,2-dioleoyl-3-trimethylammoniumpropane (DOTAP). While many studies regarding protein adsorption on the surface of liposomes with different compositions have been performed, to the best of our knowledge, the differential responses of CHOL and DOTAP upon albumin adsorption on vesicles have not yet been investigated. UV-vis spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a strong influence of the phospholipid membrane composition on protein adsorption. Hence, it was found that DOTAP-containing vesicles adsorb proteins more robustly but also aggregate in the presence of BSA, as confirmed by DLS and TEM. Separation of liposome-protein complexes from unadsorbed proteins performed by means of centrifugation and size exclusion chromatography (SEC) was also investigated. Our results show that neither method can be regarded as a golden experimental setup to study the protein corona of liposomes. Yet, SEC proved to be more successful in the separation of unbound proteins, although the amount of lipid loss upon liposome elution was higher than expected. In addition, coarse-grained molecular dynamics simulations were employed to ascertain key membrane parameters, such as the membrane thickness and area per lipid. Overall, this study highlights the importance of surface charge and membrane fluidity in influencing the extent of protein adsorption. We hope that our investigation will be a valuable contribution to better understanding protein-vesicle interactions for improved nanocarrier design.

Molecular Ballet: Investigating the Complex Interaction between Self-Assembling Dendrimers and Human Serum Albumin via Computational and Experimental Methods

Dendrimers, intricate macromolecules with highly branched nanostructures, offer unique attributes including precise control over size, shape, and functionality, making them promising candidates for a wide range of biomedical applications. The exploration of their interaction with biological environments, particularly human serum albumin (HSA), holds significant importance for biomedical utilization. In this study, the interaction between HSA and a recently developed self-assembling amphiphilic dendrimer (AD) was investigated using various experimental techniques. Fluorescence spectroscopy and isothermal titration calorimetry revealed moderate interactions between the protein and the AD nanomicelles (NMs), primarily attributed to favorable enthalpic contributions arising from electrostatic interactions and hydrogen bonding. Structural analysis indicated minimal changes in HSA upon complexation with the AD NMs, which was further supported by computational simulations demonstrating stable interactions at the atomistic level. These findings provide valuable insights into the binding mechanisms and thermodynamic parameters governing HSA/AD NM interactions, thereby contributing to the understanding of their potential biomedical applications.

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

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

Schottky Barrier-Based Built-In Electric Field for Enhanced Tumor Photodynamic Therapy

Photodynamic therapy's antitumor efficacy is hindered by the inefficient generation of reactive oxygen species (ROS) due to the photogenerated electron-hole pairs recombination of photosensitizers (PS). Therefore, there is an urgent need to develop efficient PSs with enhanced carrier dynamics. Herein, we designed Schottky junctions composed of cobalt tetroxide and palladium nanocubes (Co3O4@Pd) with a built-in electric field as effective PS. The built-in electric field enhanced photogenerated charge separation and migration, resulting in the generation of abundant electron-hole pairs and allowing effective production of ROS. Thanks to the built-in electric field, the photocurrent intensity and carrier lifetime of Co3O4@Pd were approximately 2 and 3 times those of Co3O4, respectively. Besides, the signal intensity of hydroxyl radical and singlet oxygen increased to 253.4% and 135.9%, respectively. Moreover, the localized surface plasmon resonance effect of Pd also enhanced the photothermal conversion efficiency of Co3O4@Pd to 40.50%. In vitro cellular level and in vivo xenograft model evaluations demonstrated that Co3O4@Pd could generate large amounts of ROS, trigger apoptosis, and inhibit tumor growth under near-infrared laser irradiation. Generally, this study reveals the contribution of the built-in electric field to improving photodynamic performance and provides new ideas for designing efficient inorganic PSs.

Adaptisorption of Nonporous Polymer Crystals

Although our knowledge and understanding of adsorptions in natural and artificial systems has increased dramatically during the past century, adsorption associated with nonporous polymers remains something of a mystery, hampering applications. Here we demonstrate a model system for adaptisorption of nonporous polymers, wherein dative B-N bonds and host-guest binding units act as the kinetic and thermodynamic components, respectively. The coupling of these two components enables nonporous polymer crystals to adsorb molecules from solution and undergo recrystallization as thermodynamically favored crystals. Adaptisorption of nonporous polymer crystals not only extends the types of adsorption in which the sorbate molecules are integrated in a precise and orderly manner in the sorbent systems, but also provides a facile and accurate approach to the construction of polymeric materials with precise architectures and integrated functions.

Rational Engineering of Islet Tolerance via Biomaterial-Mediated Immune Modulation

Type 1 diabetes (T1D) onset is characterized by an autoimmune attack on β islet cells within the pancreas, preventing the insulin secretion required to maintain glucose homeostasis. Targeted modulation of key immunoregulatory cell populations is a promising strategy to restore tolerance to β cells. This strategy can be used to prevent T1D onset or reverse T1D with transplanted islets. To this end, drug delivery systems can be employed to transport immunomodulatory cargo to specific cell populations that inhibit autoreactive T cell-mediated destruction of the β cell mass. The rational engineering of biomaterials into nanoscale and microscale drug carriers can facilitate targeted interactions with immune cells. The physicochemical properties of the biomaterial, the delivered immunomodulatory agent, and the target cell populations are critical variables in the design of these delivery systems. In this review, we discuss recent biomaterials-based drug delivery approaches to induce islet tolerance and the need to consider both immune and metabolic markers of disease progression.

Polymersomes as the Next Attractive Generation of Drug Delivery Systems: Definition, Synthesis and Applications

Polymersomes are artificial nanoparticles formed by the self-assembly process of amphiphilic block copolymers composed of hydrophobic and hydrophilic blocks. They can encapsulate hydrophilic molecules in the aqueous core and hydrophobic molecules within the membrane. The composition of block copolymers can be tuned, enabling control of characteristics and properties of formed polymersomes and, thus, their application in areas such as drug delivery, diagnostics, or bioimaging. The preparation methods of polymersomes can also impact their characteristics and the preservation of the encapsulated drugs. Many methods have been described, including direct hydration, thin film hydration, electroporation, the pH-switch method, solvent shift method, single and double emulsion method, flash nanoprecipitation, and microfluidic synthesis. Considering polymersome structure and composition, there are several types of polymersomes including theranostic polymersomes, polymersomes decorated with targeting ligands for selective delivery, stimuli-responsive polymersomes, or porous polymersomes with multiple promising applications. Due to the shortcomings related to the stability, efficacy, and safety of some therapeutics in the human body, polymersomes as drug delivery systems have been good candidates to improve the quality of therapies against a wide range of diseases, including cancer. Chemotherapy and immunotherapy can be improved by using polymersomes to deliver the drugs, protecting and directing them to the exact site of action. Moreover, this approach is also promising for targeted delivery of biologics since they represent a class of drugs with poor stability and high susceptibility to in vivo clearance. However, the lack of a well-defined regulatory plan for polymersome formulations has hampered their follow-up to clinical trials and subsequent market entry.

Understanding protein-nanoparticle interactions leading to protein corona formation: In vitro - in vivo correlation study

Nanoparticles (NPs) in contact with biological fluids form a biomolecular corona through interactions with proteins, lipids, and sugars, acquiring new physicochemical properties. This work explores the interaction between selected proteins (hemoglobin and fetuin-A) that may alter NP circulation time and NPs of different surface charges (neutral, positive, and negative). The interaction with key proteins albumin and transferrin, the two of the most abundant proteins in plasma was also studied. Binding affinity was investigated using quartz crystal microbalance and fluorescence quenching, while circular dichroism assessed potential conformational changes. The data obtained from in vitro experiments were compared to in vivo protein corona data. The results indicate that electrostatic interactions primarily drive protein-NP interactions, and higher binding affinity does not necessarily translate into more significant structural changes. In vitro and single protein-NP studies provide valuable insights that can be correlated with in vivo observations, opening exciting possibilities for future protein corona studies.

Dynamic metastable polymersomes enable continuous flow manufacturing

Polymersomes are polymeric analogues of liposomes with exceptional physical and chemical properties. Despite being dubbed as next-generation vesicles since their inception nearly three decades ago, polymersomes have yet to experience translation into the clinical or industrial settings. This is due to a lack of reliable methods to upscale production without compromising control over polymersome properties. Herein we report a continuous flow methodology capable of producing near-monodisperse polymersomes at scale (≥3 g/h) with the possibility of performing downstream polymersome manipulation. Unlike conventional polymersomes, our polymersomes exhibit metastability under ambient conditions, persisting for a lifetime of ca. 7 days, during which polymersome growth occurs until a dynamic equilibrium state is reached. We demonstrate how this metastable state is key to the implementation of downstream processes to manipulate polymersome size and/or shape in the same continuous stream. The methodology operates in a plug-and-play fashion and is applicable to various block copolymers.

High-Throughput Single-Cell Analysis of Nanoparticle-Cell Interactions

Understanding nanoparticle-cell interactions at single-nanoparticle and single-cell resolutions is crucial to improving the design of next-generation nanoparticles for safer, more effective, and more efficient applications in nanomedicine. This review focuses on recent advances in the continuous high-throughput analysis of nanoparticle-cell interactions at the single-cell level. We highlight and discuss the current trends in continual flow high-throughput methods for analyzing single cells, such as advanced flow cytometry techniques and inductively coupled plasma mass spectrometry methods, as well as their intersection in the form of mass cytometry. This review further discusses the challenges and opportunities with current single-cell analysis approaches and provides proposed directions for innovation in the high-throughput analysis of nanoparticle-cell interactions.

Antibiotic-Polymer Self-Assembled Nanocomplex to Reverse Phenotypic Resistance of Bacteria toward Last-Resort Antibiotic Colistin

Colistin is the last-resort antibiotic to treat multidrug-resistant (MDR) Gram-negative bacterial infections that are untreatable by other clinically available antibiotics. However, the recently merged plasmid-borne gene mobilized colistin resistance (mcr) leads to modification of the colistin target (i.e., bacterial membrane), greatly compromising the therapy outcome of colistin. To address this unmet clinical need, a nanocomplex (CMS-pEt_20 NP) of anionic prodrug colistin methanesulfonate (CMS) and guanidinium-functionalized cationic polymer pEt_20 is developed through facile self-assembly for co-delivering an antibiotic and antimicrobial polymer with membrane affinity to reverse colistin resistance. The CMS-pEt_20 NP formation enables reversal of colistin resistance and complete killing of clinically isolated mcr-positive colistin-resistant bacteria including MDR E. coli and K. pneumoniae, while monotreatment of polymer or antibiotic at equivalent doses exhibits no antibacterial activity. Mechanistic studies reveal that the CMS-pEt_20 NP enhanced the affinity of delivered CMS to the modified membrane of colistin-resistant bacteria, reviving the membrane lytic property of colistin. The increased membrane permeability caused by colistin in turn promotes an influx of pEt_20 to generate intracellular ROS stress, resulting in elimination of colistin-resistant bacteria. More importantly, a colistin-resistant mouse peritonitis-sepsis infection model demonstrates the excellent therapeutic efficacy of CMS-pEt_20 NP with 100% survival of the infected mouse. In addition, the nanocomplex is proven not toxic both in vitro and in vivo. Taken together, the self-assembled antibiotic-polymer nanocomplex with two complementary antibacterial mechanisms successfully reverses the colistin resistance phenotype in bacteria, and it can be a potential strategy to treat untreatable colistin-resistant MDR bacterial infections.

Differences in Human Plasma Protein Interactions between Various Polymersomes and Stealth Liposomes as Observed by Fluorescence Correlation Spectroscopy

A significant factor hindering the clinical translation of polymersomes as vesicular nanocarriers is the limited availability of comparative studies detailing their interaction with blood plasma proteins compared to liposomes. Here, polymersomes are self-assembled via film rehydration, solvent exchange, and polymerization-induced self-assembly using five different block copolymers. The hydrophilic blocks are composed of anti-fouling polymers, poly(ethylene glycol) (PEG) or poly(2-methyl-2-oxazoline) (PMOXA), and all the data is benchmarked to PEGylated "stealth" liposomes. High colloidal stability in human plasma (HP) is confirmed for all but two tested nanovesicles. In situ fluorescence correlation spectroscopy measurements are then performed after incubating unlabeled nanovesicles with fluorescently labeled HP or the specific labeled plasma proteins, human serum albumin, and clusterin (apolipoprotein J). The binding of HP to PMOXA-polymersomes could explain their relatively short circulation times found previously. In contrast, PEGylated liposomes also interact with HP but accumulate high levels of clusterin, providing them with their known prolonged circulation time. The absence of significant protein binding for most PEG-polymersomes indicates mechanistic differences in protein interactions and associated downstream effects, such as cell uptake and circulation time, compared to PEGylated liposomes. These are key observations for bringing polymersomes closer to clinical translation and highlighting the importance of such comparative studies.

Selective Blood Cell Hitchhiking in Whole Blood with Ionic Liquid-Coated PLGA Nanoparticles to Redirect Biodistribution After Intravenous Injection

Less than 5% of intravenously-injected nanoparticles (NPs) reach destined sites in the body due to opsonization and immune-based clearance in vascular circulation. By hitchhiking in situ onto specific blood components post-injection, NPs can selectively target tissue sites for unprecedentedly high drug delivery rates. Choline carboxylate ionic liquids (ILs) are biocompatible liquid salts <100X composed of bulky asymmetric cations and anions. This class of ILs has been previously shown to significantly extend circulation time and redirect biodistribution in BALB/c mice post-IV injection via hitchhiking on red blood cell (RBC) membranes. Herein, we synthesized & screened 60 choline carboxylic acid-based ILs to coat PLGA NPs and present the impact of structurally engineering the coordinated anion identity to selectively interface and hitchhike lymphocytes, monocytes, granulocytes, platelets, and RBCs in whole mouse blood for in situ targeted drug delivery. Furthermore, we find this nanoparticle platform to be biocompatible (non-cytotoxic), translate to human whole blood by resisting serum uptake and maintaining modest hitchhiking, and also significantly extend circulation retention over 24 hours in BALB/c healthy adult mice after IV injection. Because of their altered circulation profiles, we additionally observe dramatically different organ accumulation profiles compared to bare PLGA NPs. This study establishes an initial breakthrough platform for a modular and transformative targeting technology to hitchhike onto blood components with high efficacy and safety in the bloodstream post-IV administration.

Advancements in pH-responsive nanocarriers: enhancing drug delivery for tumor therapy

INTRODUCTION

Tumors pose a significant global economic and health burden, with conventional cancer treatments lacking tumor specificity, leading to limited efficiency and undesirable side effects. Targeted tumor therapy is imminent. Tumor cells produce lactate and hydrogen ions (H+) by Warburg effect, forming an acidic tumor microenvironment (TME), which can be employed to design targeted tumor therapy. Recently, progress in nanotechnology has led to the development of pH-responsive nanocarriers, which have gathered significant attention. Under acidic tumor conditions, they exhibit targeted accumulation within tumor sites and controlled release profiles of therapeutic reagents, enabling precise tumor therapy.

AREAS COVERED

This review comprehensively summarize the principles underlying pH-responsive features, discussing various types of pH-responsive nanocarriers, their advantages, and limitations. Innovative therapeutic drugs are also examined, followed by an exploration of recent advancements in applying various pH-responsive nanocarriers as delivery systems for enhanced tumor therapy.

EXPERT OPINIONS

pH-responsive nanocarriers have garnered significant attention for their capability to achieve targeted accumulation of therapeutic agents at tumor sites and controlled drug delivery profiles, ultimately increasing the efficiency of tumor eradication. It is anticipated that the employment of pH-responsive nanocarriers will elevate the effectiveness and safety of tumor therapy, contributing to improved overall outcomes.

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.

Stealth and pseudo-stealth nanocarriers

The stealth effect plays a central role on capacitating nanomaterials for drug delivery applications through improving the pharmacokinetics such as blood circulation, biodistribution, and tissue targeting. Here based on a practical analysis of stealth efficiency and a theoretical discussion of relevant factors, we provide an integrated material and biological perspective in terms of engineering stealth nanomaterials. The analysis surprisingly shows that more than 85% of the reported stealth nanomaterials encounter a rapid drop of blood concentration to half of the administered dose within 1 h post administration although a relatively long β-phase is observed. A term, pseudo-stealth effect, is used to delineate this common pharmacokinetics behavior of nanomaterials, that is, dose-dependent nonlinear pharmacokinetics because of saturating or depressing bio-clearance of RES. We further propose structural holism can be a watershed to improve the stealth effect; that is, the whole surface structure and geometry play important roles, rather than solely relying on a single factor such as maximizing repulsion force through polymer-based steric stabilization (e.g., PEGylation) or inhibiting immune attack through a bio-inspired component. Consequently, engineering delicate structural hierarchies to minimize attractive binding sites, that is, minimal charges/dipole and hydrophobic domain, becomes crucial. In parallel, the pragmatic implementation of the pseudo-stealth effect and dynamic modulation of the stealth effect are discussed for future development.

Role of nanotechnology in the prolonged release of drugs by the subcutaneous route

INTRODUCTION

Subcutaneous physiology is distinct from other parenteral routes that benefit the administration of prolonged-release formulations. A prolonged-release effect is particularly convenient for treating chronic diseases because it is associated with complex and often prolonged posologies. Therefore, drug-delivery systems focused on nanotechnology are proposed as alternatives that can overcome the limitations of current therapeutic regimens and improve therapeutic efficacy.

AREAS COVERED

This review presents an updated systematization of nanosystems, focusing on their applications in highly prevalent chronic diseases. Subcutaneous-delivered nanosystem-based therapies comprehensively summarize nanosystems, drugs, and diseases and their advantages, limitations, and strategies to increase their translation into clinical applications. An outline of the potential contribution of quality-by-design (QbD) and artificial intelligence (AI) to the pharmaceutical development of nanosystems is presented.

EXPERT OPINION

Although recent academic research and development (R&D) advances in the subcutaneous delivery of nanosystems have exhibited promising results, pharmaceutical industries and regulatory agencies need to catch up. The lack of standardized methodologies for analyzing in vitro data from nanosystems for subcutaneous administration and subsequent in vivo correlation limits their access to clinical trials. There is an urgent need for regulatory agencies to develop methods that faithfully mimic subcutaneous administration and specific guidelines for evaluating nanosystems.

Effect of Albumin Corona Conformation on In Vitro and In Vivo Profiles of Intravenously Administered Nanoparticles

Under physiological conditions, nanoparticles (NPs) inevitably interact with proteins, resulting in extensive protein adsorption and the formation of a protein corona. Recent studies have shown that the different surface properties of NPs lead to varying degrees of conformational changes of adsorbed proteins. However, the impact of corona protein conformation on the in vitro and in vivo profiles of NPs remain largely unexplored. Herein, d-α-tocopherol polyethylene glycol 1000 succinate-based NPs with natural human serum albumin (HSA_N) corona or thermally denatured HSA (HSA_D) corona were synthesized following a previously established method. We then conducted a systematic study of the protein conformation as well as adsorption behaviors. Additionally, the impact of protein corona conformation on the NPs profiles in vitro and in vivo were elucidated to gain insight into its biological behaviors as a targeted delivery system for renal tubule diseases. Overall, NPs modified by HSA_N corona showed improved serum stability, greater cell uptake efficiency, better renal tubular targetability, and therapeutic efficacy on acute kidney injury in rats than NPs modified by HSA_D corona. Hence, the conformation of protein adsorbed on the surface of NPs may impact the in vitro and in vivo profiles of NPs.

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.

Cytosolic perfluorocarbon delivery to platelets via albumin for antithrombotic therapy

Thrombosis is a major contributor to global disease burden. Antiplatelet therapy is the critical approach to prevent thrombosis by reducing platelet reactivity. However, classical antiplatelet strategies generally interfere with platelet integrin α_IIbβ₃-mediated platelet activation, thereby facing severe bleeding risk. To break the limitation, we described an integrin α_IIbβ₃-independent antiplatelet method by cytosolic delivery of nanoscale perfluorocarbon (PFC) to platelets via albumin carrier. Denatured albumin was found to build high affinity with platelets to mediate cytosolic PFC delivery. While, cytosolic PFC impaired cytoskeleton reorganization during platelet activation to inhibit relevant platelet functions, but avoided to interfere with integrin α_IIbβ₃. We proved that this α_IIbβ₃-indenpendent antiplatelet pattern showed potential antiplatelet effect with low bleeding risk to prevent thrombosis in various thrombosis models. Together, cytosolic PFC delivery via albumin is a promising antiplatelet approach, and will provide an alternative regimen for current antithrombotic therapy.

In vitro assessment of varying peptide surface density on the suppression of angiogenesis by micelles displaying αvβ3 blocking peptides

Ligand targeted therapy (LTT) is a precision medicine strategy that can selectively target diseased cells while minimizing off-target effects on healthy cells. Integrin-targeted LTT has been developed recently for angiogenesis-related diseases. However, the clinical success is based on the optimal design of the nanoparticles for inducing receptor clustering within the cell membrane. The current study focused on determining the surface density of Ser-Asp-Val containing anti-integrin heptapeptide on poly (ethylene glycol)-b-poly(propylene sulfide) micelles (MC) required for anti-angiogenic effects on HUVECs. Varying peptide density on PEG-b-PPS/Pep-PA MCs (Pep-PA-Peptide-palmitoleic acid) was used in comparison to a random peptide (SGV) and cRGD (cyclic-Arginine-Glycine-Aspartic acid) construct at 5%-density on MCs. Immunocytochemistry using CD51/CD31 antibody was performed to study the integrin blocking by MCs. In addition, the expression of VWF and PECAM-1, cell migration and tube formation was evaluated in the presence of PEG-b-PPS/Pep-PA MCs. The results show PEG-b-PPS/SDV-PA MCs with 5%-peptide density to achieve significantly higher αvβ3 blocking compared to random peptide as well as cRGD. In addition, αvβ3 blocking via MCs further reduced the expression of vWF and PECAM-1 angiogenesis protein expression in HUVECs. Although a significant level of integrin blocking was observed for 1%-peptide density on MCs, the cell migration and tube formation were not significantly affected. In conclusion, the results of this study demonstrate that the peptide surface density on PEG-b-PPS/Pep-PA MCs has a significant impact in integrin blocking as well as inhibiting angiogenesis during LTT. The outcomes of this study provides insight into the design of ligand targeted nanocarriers for various disease conditions.

Drug delivery targets and strategies to address mast cell diseases

INTRODUCTION

Current and developing mast cell therapeutics are reliant on small molecule drugs and biologics, but few are truly selective for mast cells. Most have cellular and disease-specific limitations that require innovation to overcome longstanding challenges to selectively targeting and modulating mast cell behavior. This review is designed to serve as a frame of reference for new approaches that utilize nanotechnology or combine different drugs to increase mast cell selectivity and therapeutic efficacy.

AREAS COVERED

Mast cell diseases include allergy and related conditions as well as malignancies. Here, we discuss the targets of existing and developing therapies used to treat these disease pathologies, classifying them into cell surface, intracellular, and extracellular categories. For each target discussed, we discuss drugs that are either the current standard of care, under development, or have indications for potential use. Finally, we discuss how novel technologies and tools can be used to take existing therapeutics to a new level of selectivity and potency against mast cells.

EXPERT OPINION

There are many broadly and very few selectively targeted therapeutics for mast cells in allergy and malignant disease. Combining existing targeting strategies with technology like nanoparticles will provide novel platforms to treat mast cell disease more selectively.