Deep Profiling of Plasma Proteoforms with Engineered Nanoparticles for Top-Down Proteomics.

The dynamic range challenge for the detection of proteins and their proteoforms in human plasma has been well documented. Here, we use the nanoparticle protein corona approach to enrich low-abundance proteins selectively and reproducibly from human plasma and use top-down proteomics to quantify differential enrichment for the 2841 detected proteoforms from 114 proteins. Furthermore, nanoparticle enrichment allowed top-down detection of proteoforms between ∼1 µg/mL and ∼10 pg/mL in absolute abundance, providing up to a 105-fold increase in proteome depth over neat plasma in which only proteoforms from abundant proteins (>1 µg/mL) were detected. The ability to monitor medium and some low-abundant proteoforms through reproducible enrichment significantly extends the applicability of proteoform research by adding depth beyond albumin, immunoglobins, and apolipoproteins to uncover many involved in immunity and cell signaling. As proteoforms carry unique information content relative to peptides, this report opens the door to deeper proteoform sequencing in clinical proteomics of disease or aging cohorts.

Design of Auto-Adaptive Drug Delivery System for Effective Delivery of Peptide Drugs to Overcoming Mucus and Epithelial Barriers.

Oral administration of peptide represents a promising delivery route, however, it is hindered by the harsh gastrointestinal environment, leading to low in vivo absorption. In this study, auto-adaptive protein corona-AT 1002-cationic liposomes (Pc-AT-CLs) are constructed with the characteristic of hydrophilic and electrically neutral surface properties for the encapsulation of liraglutide. BSA protein corona is used to coat AT-CLs reducing the adherence of mucus, and may fall off after penetrating the mucus layer. Transmucus transport experiment demonstrated that the mucus penetration amount of Pc-AT-CLs are 1.45 times that of AT-CLs. After penetrating the mucus layer, AT-CLs complete transmembrane transport by the dual action of AT and cationic surface properties. Transmembrane transport experiment demonstrated that the apparent permeability coefficient (Papp) of AT-CLs is 2.03 times that of CLs. In vivo tests demonstrated that Pc-AT-CLs exhibited a significant hypoglycemic effect and enhanced the relative bioavailability comparing to free liraglutide. Pc-AT-CLs protect liraglutide from degradation, facilitate its absorption, and ultimately improve its oral bioavailability.

Beyond basic characterization and omics: Immunomodulatory roles of platelet-derived extracellular vesicles unveiled by functional testing.

Renowned for their role in haemostasis and thrombosis, platelets are also increasingly recognized for their contribution in innate immunity, immunothrombosis and inflammatory diseases. Platelets express a wide range of receptors, which allows them to reach a variety of activation endpoints and grants them immunomodulatory functions. Activated platelets release extracellular vesicles (PEVs), whose formation and molecular cargo has been shown to depend on receptor-mediated activation and environmental cues. This study compared the immunomodulatory profiles of PEVs generated via activation of platelets by different receptors, glycoprotein VI, C-type lectin-like receptor 2 and combining all thrombin-collagen receptors. Functional assays in vivo in zebrafish and in vitro in human macrophages highlighted distinct homing and secretory responses triggered by the PEVs. In contrast, omics analyses of protein and miRNA cargo combined with physicochemical particle characterization found only subtle differences between the activated PEV types, which were insufficient to predict their different immunomodulatory functions. In contrast, constitutively released PEVs, formed in the absence of an exogenous activator, displayed a distinct immunomodulatory profile from the receptor-induced PEVs. Our findings underscore that PEVs are tunable through receptor-mediated activation. To truly comprehend their role(s) in mediating platelet functions among immune cells, conducting functional assays is imperative.

Serum-derived protein coronas affect nanoparticle interactions with brain cells.

Neuronanomedicine is an emerging field bridging the gap between neuromedicine and novel nanotherapeutics. Despite promise, clinical translation of neuronanomedicine remains elusive, possibly due to a dearth of information regarding the effect of the protein corona on these neuronanomedicines. The protein corona, a layer of proteins adsorbed to nanoparticles following exposure to biological fluids, ultimately determines the fate of nanoparticles in biological systems, dictating nanoparticle-cell interactions. To date, few studies have investigated the effect of the protein corona on interactions with brain-derived cells, an important consideration for the development of neuronanomedicines. Here, two polymeric nanoparticles, poly(lactic-co-glycolic acid) (PLGA) and PLGA-polyethylene glycol (PLGA-PEG), were used to obtain serum-derived protein coronas. Protein corona characterization and liquid chromatography mass spectrometry analysis revealed distinct differences in biophysical properties and protein composition. PLGA protein coronas contained high abundance of globins (60%) and apolipoproteins (21%), while PLGA-PEG protein coronas contained fewer globins (42%) and high abundance of protease inhibitors (28%). Corona coated PLGA nanoparticles were readily internalized into microglia and neuronal cells, but not into astrocytes. Internalization of nanoparticles was associated with pro-inflammatory cytokine release and decreased neuronal cell viability, however, viability was rescued in cells treated with corona coated nanoparticles. These results showcase the importance of the protein corona in mediating nanoparticle-cell interactions.

The role of protein corona in advancing plasma proteomics.

The protein corona, a layer of biomolecules forming around nanoparticles in biological environments, critically influences nanoparticle interactions with biosystems, affecting pharmacokinetics and biological outcomes. Initially, the protein corona presented challenges for nanomedicine and nanotoxicology, such as nutrient depletion in cell cultures and masking of nanoparticle-targeting species. However, recent advancements have highlighted its potential in environmental toxicity, proteomics, and immunology. This viewpoint focuses on leveraging the protein corona to enhance the depth of plasma proteome analysis, addressing challenges posed by the high dynamic range of protein concentrations in plasma. The protein corona simplifies sample preparation, enriches low-abundance proteins, and improves proteome coverage. Innovations include using diverse nanoparticles and spiking small molecules to increase the number of quantified proteins. Reproducibility issues across core facilities necessitate standardized protocols. Moreover, top-down proteomics enables proteoform-specific measurements, providing deeper insights into protein corona composition. Future research should aim at improving top-down proteomics techniques and integrating protein corona studies and proteomics for personalized medicine and advanced diagnostics.

Protein corona dynamicity contributes to biological destiny disparities of nanoparticles.

Extracellular protein coronas (exPCs), which have been identified in various biofluids, are recognized for their pivotal role in mediating the interaction between nanoparticles and the cytomembrane. However, it is still unclear whether various exPCs can induce different levels of intracellular proteostasis, which is of utmost importance in preserving cellular function, and eliciting distinct intracellular biological behaviors. To investigate this, two types of exPC-coated iron oxide nanoparticles (IONPs) are prepared and used to investigate the influence of exPCs on extracellular and intracellular biological outcomes. The results demonstrate that the formation of exPCs promotes the colloidal stability of IONPs, and the discrepancies in the components of the two exPCs, including opsonin, dysopsonin, and lipoprotein, are responsible for the disparities in cellular uptake and endocytic pathways. Moreover, the differential evolution of the two exPCs during cellular internalization leads to distinct autophagy and glycolysis activities, which can be attributed to the altered depletion of angiopoietin 1 during the formation of intracellular protein coronas, which ultimately impacts the PI3K/AKT-mTOR signaling. These findings offer valuable insights into the dynamic characteristics of exPCs during cellular internalization, and their consequential implications for cellular internalization and intracellular metabolism activity, which may facilitate the comprehension of PCs on biological effects of NPs and expedite the design and application of biomedical nanoparticles.

Renal-Targeted Drug Delivery by Chitosan Oligosaccharide Micelles with HSA-Enriched Protein Corona for the Treatment of Ischemia/Reperfusion-Induced Acute Kidney Injury.

Renal-specific nanoparticulate drug delivery systems have shown great potential in reducing systemic side effects and improving the safety and efficacy of treatments for renal diseases. Here, stearic acid-grafted chitosan oligosaccharide (COS-SA) was synthesized as a renal-targeted carrier due to the high affinity of the 2-glucosamine moiety on COS to the megalin receptor expressed on renal proximal tubular epithelial cells. Specifically, COS-SA/CLT micelles were prepared by encapsulating celastrol (CLT) with COS-SA, and different proportions of human serum albumin (HSA) were then adsorbed onto its surface to explore the interaction between the protein corona and cationic polymeric micelles. Our results showed that a multilayered protein corona, consisting of an inner "hard" corona and an outer "soft" corona, was formed on the surface of COS-SA/CLT@HSA8, which was beneficial in preventing its recognition and phagocytosis by macrophages. The formation of HSA protein corona on COS-SA/CLT micelles also increased its accumulation in the renal tubules. Furthermore, the electropositivity of COS-SA/CLT micelles affected the conformation of adsorbed proteins to various degrees. During the adsorption process, the protein corona on the surface of COS-SA/CLT@HSA1 was partially denatured. Overall, COS-SA/CLT and COS-SA/CLT@HSA micelles demonstrated sufficient safety with renal targeting potential, providing a viable strategy for the management of ischemia/reperfusion-induced acute kidney injury.

Mass Spectrometry-Based Top-Down Proteomics in Nanomedicine: Proteoform-Specific Measurement of Protein Corona.

Conventional mass spectrometry (MS)-based bottom-up proteomics (BUP) analysis of the protein corona [i.e., an evolving layer of biomolecules, mostly proteins, formed on the surface of nanoparticles (NPs) during their interactions with biomolecular fluids] enabled the nanomedicine community to partly identify the biological identity of NPs. Such an approach, however, fails to pinpoint the specific proteoforms─distinct molecular variants of proteins in the protein corona. The proteoform-level information could potentially advance the prediction of the biological fate and pharmacokinetics of nanomedicines. Recognizing this limitation, this study pioneers a robust and reproducible MS-based top-down proteomics (TDP) technique for characterizing proteoforms in the protein corona. Our TDP approach has successfully identified about 900 proteoforms in the protein corona of polystyrene NPs, ranging from 2 to 70 kDa, revealing proteoforms of 48 protein biomarkers with combinations of post-translational modifications, signal peptide cleavages, and/or truncations─details that BUP could not fully discern. This advancement in MS-based TDP offers a more advanced approach to characterize NP protein coronas, deepening our understanding of NPs' biological identities. We, therefore, propose using both TDP and BUP strategies to obtain more comprehensive information about the protein corona, which, in turn, can further enhance the diagnostic and therapeutic efficacy of nanomedicine technologies.

Systemically targeting monocytic myeloid-derived suppressor cells using dendrimers and their cell-level biodistribution kinetics.

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

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.

Serum protein albumin and chromium: Mechanistic insights into the interaction between ions, nanoparticles, and protein.

The interaction of human proteins and metal species, both ions and nanoparticles, is poorly understood despite their growing importance. These materials are the by-products of corrosion processes and are of relevance for food and drug manufacturing, nanomedicine, and biomedical implant corrosion. Here, we study the interaction of Cr(III) ions and chromium oxide nanoparticles with bovine serum albumin in physiological conditions. This study combined electrophoretic mobility measurements, spectroscopy, and time-of-flight secondary ion mass spectrometry with principal component analysis. It was determined that neither metal species resulted in global albumin unfolding. The Cr(III) ions interacted strongly with amino acids found in previously discovered metal binding sites, but also were most strongly implicated in the interaction with negatively charged acid residues, suggesting an electrostatic interaction. Bovine serum albumin (BSA) was found to bind to the Cr2O3 nanoparticles in a preferential orientation, due to electrostatic interactions between the positive amino acid residues and the negative chromium oxide nanoparticle surface. These findings ameliorate our understanding of the interaction between trivalent chromium ions and nanoparticles, and biological macromolecules.

Submicron immunoglobulin particles exhibit FcγRII-dependent toxicity linked to autophagy in TNFα-stimulated endothelial cells.

In intravenous immunoglobulins (IVIG), and some other immunoglobulin products, protein particles have been implicated in adverse events. Role and mechanisms of immunoglobulin particles in vascular adverse effects of blood components and manufactured biologics have not been elucidated. We have developed a model of spherical silica microparticles (SiMPs) of distinct sizes 200-2000 nm coated with different IVIG- or albumin (HSA)-coronas and investigated their effects on cultured human umbilical vein endothelial cells (HUVEC). IVIG products (1-20 mg/mL), bare SiMPs or SiMPs with IVIG-corona, did not display significant toxicity to unstimulated HUVEC. In contrast, in TNFα-stimulated HUVEC, IVIG-SiMPs induced decrease of HUVEC viability compared to HSA-SiMPs, while no toxicity of soluble IVIG was observed. 200 nm IVIG-SiMPs after 24 h treatment further increased ICAM1 (intercellular adhesion molecule 1) and tissue factor surface expression, apoptosis, mammalian target of rapamacin (mTOR)-dependent activation of autophagy, and release of extracellular vesicles, positive for mitophagy markers. Toxic effects of IVIG-SiMPs were most prominent for 200 nm SiMPs and decreased with larger SiMP size. Using blocking antibodies, toxicity of IVIG-SiMPs was found dependent on FcγRII receptor expression on HUVEC, which increased after TNFα-stimulation. Similar results were observed with different IVIG products and research grade IgG preparations. In conclusion, submicron particles with immunoglobulin corona induced size-dependent toxicity in TNFα-stimulated HUVEC via FcγRII receptors, associated with apoptosis and mTOR-dependent activation of autophagy. Testing of IVIG toxicity in endothelial cells prestimulated with proinflammatory cytokines is relevant to clinical conditions. Our results warrant further studies on endothelial toxicity of sub-visible immunoglobulin particles.

Systemic Brain Delivery of Oligonucleotide Therapeutics Enhanced by Protein Corona-Assisted DNA Cubes.

The systemic delivery of oligonucleotide therapeutics to the brain is challenging but highly desirable for the treatment of brain diseases undruggable with traditional small-molecule drugs. In this study, a set of DNA nanostructures is prepared and screened them to develop a protein corona-assisted platform for the brain delivery of oligonucleotide therapeutics. The biodistribution analysis of intravenously injected DNA nanostructures reveals that a cube-shaped DNA nanostructure (D-Cb) can penetrate the brain-blood barrier (BBB) and reach the brain tissue. The brain distribution level of D-Cb is comparable to that of other previous nanoparticles conjugated with brain-targeting ligands. Proteomic analysis of the protein corona formed on D-Cb suggests that its brain distribution is driven by endothelial receptor-targeting ligands in the protein corona, which mediate transcytosis for crossing the BBB. D-Cb is subsequently used to deliver an antisense oligonucleotide (ASO) to treat glioblastoma multiforme (GBM) in mice. While free ASO is unable to reach the brain, ASO loaded onto D-Cb is delivered efficiently to the brain tumor region, where it downregulates the target gene and exerts an anti-tumor effect on GBM. D-Cb is expected to serve as a viable platform based on protein corona formation for systemic brain delivery of oligonucleotide therapeutics.

Standardizing Protein Corona Characterization in Nanomedicine: A Multicenter Study to Enhance Reproducibility and Data Homogeneity.

We recently revealed significant variability in protein corona characterization across various proteomics facilities, indicating that data sets are not comparable between independent studies. This heterogeneity mainly arises from differences in sample preparation protocols, mass spectrometry workflows, and raw data processing. To address this issue, we developed standardized protocols and unified sample preparation workflows, distributing uniform protein corona digests to several top-performing proteomics centers from our previous study. We also examined the influence of using similar mass spectrometry instruments on data homogeneity and standardized database search parameters and data processing workflows. Our findings reveal a remarkable stepwise improvement in protein corona data uniformity, increasing overlaps in protein identification from 11% to 40% across facilities using similar instruments and through a uniform database search. We identify the key parameters behind data heterogeneity and provide recommendations for designing experiments. Our findings should significantly advance the robustness of protein corona analysis for diagnostic and therapeutics applications.

Manipulation of Serum Protein Adsorption by Nanoengineered Biomaterials Influences Subsequent Immune Responses.

The adsorption of serum proteins on biomaterial surfaces is a critical determinant for the outcome of medical procedures and therapies, which involve inserting materials and devices into the body. In this study, we aimed to understand how surface topography at the nanoscale influences the composition of the protein corona that forms on the (bio)material surface when placed in contact with serum proteins. To achieve that, we developed nanoengineered model surfaces with finely tuned topography of 16, 40, and 70 nm, overcoated with methyl oxazoline to ensure uniform outermost chemistry across all surfaces. Our findings revealed that within the studied height range, surface nanotopography had no major influence on the overall quantity of adsorbed proteins. However, significant alterations were observed in the composition of the adsorbed protein corona. For instance, clusterin adsorption decreased on all the nanotopography-modified surfaces. Conversely, there was a notable increase in the adsorption of ApoB and IgG gamma on the 70 nm nanotopography. In comparison, the adsorption of albumin was greater on surfaces that had a topography scale of 40 nm. Analysis of the gene enrichment data revealed a reduction in protein adsorption across all immune response-related biological pathways on nanotopography-modified surfaces. This reduction became more pronounced for larger surface nanoprotrusions. Macrophages were used as representative immune cells to assess the influence of the protein corona composition on inflammatory outcomes. Gene expression analysis demonstrated reduced inflammatory responses on the nanotopographically modified surface, a trend further corroborated by cytokine analysis. These findings underscore the potential of precisely engineered nanotopography-coated surfaces for augmenting biomaterial functionality.

Strong binding between nanoplastic and bacterial proteins facilitates protein corona formation and reduces nanoplastics toxicity.

The interaction and combination of nanoplastics with microorganisms, enzymes, plant proteins, and other substances have garnered considerable attention in current research. This study specifically examined the interaction and biological effects of NPs and proteins. The findings indicated that the presence of externally wrapped proteins alters the original morphology and surface roughness of nanoplastics, leading to the formation of unevenly distributed coronas on the surface. This confirms that nanoplastics can interact with proteins to form protein coronas. The study characterized the adsorption behavior of bacterial proteins on unmodified, amino-modified, and carboxyl-modified nanoplastics using Langmuir and Freundlich isotherm models, showing that the adsorption process of the three nanoplastics on bacterial proteins was mainly controlled by chemisorption. Fluorescence spectroscopy revealed a higher binding affinity of unmodified nanoplastics. Nearly 40 % of the proteins in the protein corona of unmodified NPs are involved in metabolite production and electron transport processes. Nearly 50 % of the proteins in the protein corona of amino-modified NPs are involved in cellular metabolic processes, followed by enzymes that carry out redox reactions. The protein corona of carboxyl-modified NPs has the highest number of proteins involved in metabolic pathways, followed by proteins involved in energy-electron transfer. The formation of protein coronas on NPs with different surface modifications can reduce the toxicity of nanoplastics to bacteria to a certain extent compared to pure nanoplastics, especially amino-modified NPs, which show a significant increase in bacterial survival. The formation of protein coronas on NPs leads to varying degrees of decrease in bacterial ROS and MDA generation, with amino-modified NPs showing the most reduction; SOD and CAT exhibit varying degrees of increase and decrease. These findings not only advance our understanding of the biological impacts of NPs but also provide a basis for future in-depth investigations into the pathways of NP contamination in real environments.

Human Serum Albumin Protein Corona in Prussian Blue Nanoparticles.

Prussian Blue nanoparticles (PBnps) are now popular in nanomedicine thanks to the FDA approval of PB. Despite the numerous papers suggesting or describing the in vivo use of PBnps, no studies have been carried out on the formation of a protein corona on the PBnp surface and its stabilizing role. In this paper, we studied qualitatively and quantitatively the corona formed by the most abundant protein of blood, human serum albumin (HSA). Cubic PBnps (41 nm side), prepared in citric acid solution at PB concentration 5 × 10-4 M, readily form a protein corona by redissolving ultracentrifuged PBnp pellets in HSA solutions, with CHSA ranging from 0.025 to 7.0 mg/mL. The basic decomposition of PBnp@HSA was studied in phosphate buffer at the physiological pH value of 7.4. Increased stability with respect to uncoated PBnps was observed at all concentrations, but a minimum CHSA value of 3.0 mg/mL was determined to obtain stability identical to that observed at serum-like HSA concentrations (35-50 mg/mL). Using a modified Lowry protocol, the quantity of firmly bound HSA in the protein corona (hard corona) was determined for all the CHSA used in the PBnp@HSA synthesis, finding increasing quantities with increasing CHSA. In particular, an HSA/PBnp number in the 1500-2300 range was found for CHSA 3.0-7.0 mg/mL, largely exceeding the 180 HSA/PBnp value calculated for an HSA monolayer on a PBnp. Finally, the stabilization brought by the HSA corona allowed us to carry out pH-spectrophotometric titrations on PBnp@HSA in the 3.5-9-0 pH range, revealing a pKa value of 6.68 for the water molecules bound to the Fe3+ centers on the PBnp surface, whose deprotonation is responsible for the blue-shift of the PBnp band from 706 nm (acidic solution) to 685 nm (basic solution).

Interaction of zein/HP-ß-CD nanoparticles with digestive enzymes: Enhancing curcumin bioavailability.

The low bioavailability of polyphenolic compounds due to poor solubility and stability is a major challenge. Encapsulation of polyphenols in zein-based composite nanoparticles can improve the water dispersion, stability, targeted delivery, and controlled release of polyphenols in the gastrointestinal tract. In this study, we investigated the fluorescence properties, bioactivity, and microstructural characteristics of polyphenols during digestion, revealing that zein nanoparticles protect polyphenols from gastric degradation and promote their sustained release in the small intestine. The effects of different ionic species and salt ion concentrations on the digestive properties of polyphenol complex delivery systems have also been explored. In addition, the formation of "protein corona" structures during digestion may affect bioavailability. These findings highlight the potential of nanoparticle formulations to improve polyphenol stability and absorption. The results of this study may provide new insights and references for the study of polyphenol bioavailability enhancement.

Multifunctional biomolecular corona-inspired nanoremediation of antibiotic residues.

Facing complex and variable emerging antibiotic pollutants, the traditional development of functional materials is a "trial-and-error" process based on physicochemical principles, where laborious steps and long timescales make it difficult to accelerate technical breakthroughs. Notably, natural biomolecular coronas derived from highly tolerant organisms under significant contamination scenarios can be used in conjunction with nanotechnology to tackling emerging contaminants of concern. Here, super worms (Tubifex tubifex) with high pollutant tolerance were integrated with nano-zero valent iron (nZVI) to effectively reduce the content of 17 antibiotics in wastewater within 7 d. Inspired by the synergistic remediation, nZVI-augmented worms were constructed as biological nanocomposites. Neither nZVI (0.3 to 3 g/L) nor worms (104 to 105 per liter) alone efficiently degraded florfenicol (FF, as a representative antibiotic), while their composite removed 87% of FF (3 µmol/L). Under antibiotic exposure, biomolecules secreted by worms formed a corona on and modified the nZVI particle surface, enabling the nano-bio interface greater functionality, including responsiveness, enrichment, and reduction. Mechanistically, FF exposure activated glucose-alanine cycle pathways that synthesize organic acids and amines as major metabolites, which were assembled into vesicles and secreted, thereby interacting with nZVI in a biologically response design strategy. Lactic acid and urea formed hydrogen bonds with FF, enriched analyte presence at the heterogeneous interface. Succinic and lactic acids corroded the nZVI passivation layer and promoted electron transfer through surface conjugation. This unique strategy highlights biomolecular coronas as a complex resource to augment nano-enabled technologies and will provide shortcuts for rational manipulation of nanomaterial surfaces with coordinated multifunctionalities.

Brain-targeted drug delivery by in vivo functionalized liposome with stable D-peptide ligand.

Brain-targeted drug delivery poses a great challenge due to the blood-brain barrier (BBB). In a previous study, we have developed a peptide-modified stealth liposome (SP-sLip) to enhance BBB penetration via the adsorption of apolipoproteins in plasma. SP is an 11-amino acid peptide derived from 25 to 35 of the Amyloid ß peptide (Aß1-42), which is a nature ligand of apolipoproteins. Although freshly prepared SP-sLip exhibited efficient brain targeting performance, it occured self-aggregation and instability in storage. In this study, we developed a D-peptide ligand according to the reverse sequence of SP with D-amino acids, known as DSP, to improve the stability in storage. Notably, DSP exhibited a reduced tendency for self-aggregation and improved stability in comparison to the SP peptide. Furthermore, compared to SP-sLip, DSP-modified sLip (DSP-sLip) demonstrated enhanced stability (>2 weeks), prolonged blood circulation (AUC increased 44.4%), reduced liver and spleen accumulation (reduced by 2.23 times and 1.86 times) with comparable brain-targeting efficiency. Similar to SP-sLip, DSP-sLip selectively adsorbed apolipoprotein A1, E, and J in the blood to form functionalized protein corona, thus crossing BBB via apolipoprotein receptor-mediated transcytosis. These findings underscored the importance of ligand stability in the in vitro and in vivo performance of brain-targeted liposomes, therefore paving the way for the design and optimization of efficient and stable nanocarriers.