Mechanistic Understanding of the Biological Responses to Polymeric Nanoparticles

Recent Advances in Nanomedicine for Ocular Fundus Neovascularization Disease Management

As an indispensable part of the human sensory system, visual acuity may be impaired and even develop into irreversible blindness due to various ocular pathologies. Among ocular diseases, fundus neovascularization diseases (FNDs) are prominent etiologies of visual impairment worldwide. Intravitreal injection of anti-vascular endothelial growth factor drugs remains the primary therapy but is hurdled by common complications and incomplete potency. To renovate the current therapeutic modalities, nanomedicine emerged as the times required, which is endowed with advanced capabilities, able to fulfill the effective ocular fundus drug delivery and achieve precise drug release control, thus further improving the therapeutic effect. This review provides a comprehensive summary of advances in nanomedicine for FND management from state-of-the-art studies. First, the current therapeutic modalities for FNDs are thoroughly introduced, focusing on the key challenges of ocular fundus drug delivery. Second, nanocarriers are comprehensively reviewed for ocular posterior drug delivery based on the nanostructures: polymer-based nanocarriers, lipid-based nanocarriers, and inorganic nanoparticles. Thirdly, the characteristics of the fundus microenvironment, their pathological changes during FNDs, and corresponding strategies for constructing smart nanocarriers are elaborated. Furthermore, the challenges and prospects of nanomedicine for FND management are thoroughly discussed.

Photodynamic effect of vascular-targeted polyphenol nanoparticles on Endothelial cells

BACKGROUND

Port wine stains (PWS) are vascular malformations, and photodynamic therapy (PDT) is a promising treatment. Emerging drug delivery methods employ nanoparticles (NPs) to enhance drug permeability and retention in diseased blood vessels and improve drug bioavailability. (-) -epigallocatechin-3-gallate glycine (EGCG) has anti-angiogenetic effects and boosts photodynamic therapy. Chlorin e6 (Ce6) is capable of efficiently producing singlet oxygen, rendering it a very promising photosensitizer for utilization in nanomedicine.

MATERIAL AND METHODS

EGCG-Ce6-NPs were synthesized and characterized using various techniques. The photodynamic effects of EGCG-Ce6-NPs on endothelial cells were evaluated. The compatibility and toxicity of the nanoparticle was tested using the CCK-8 assay. The intracellular uptake of the nanoparticle was observed using an inverted fluorescence microscope, and the intracellular fluorescence intensity was detected using flow cytometry. The ROS generation and apoptosis induced by EGCG-Ce6-NPs was observed using confocal laser scanning microscopy and flow cytometry respectively.

RESULTS

EGCG-Ce6-NPs exhibited stability, spherical shape of uniform size while reducing the particle diameter, low polydisperse profile and retaining the ability to effectively generate singlet oxygen. These characteristics suggest promising potential for enhancing drug permeability and retention. Additionally, EGCG-Ce6-NPs demonstrated good compatibility with endothelial cells and enhanced intracellular uptake of Ce6. Furthermore, EGCG-Ce6-NPs increased activation efficiency, induced significant toxicity, more reactive oxygen species, and a higher rate of late apoptosis after laser irradiation.

CONCLUSION

This in vitro study showed the potentials EGCG-Ce6-NPs for the destruction of endothelial cells in vasculature.

An enhanced cardio-protective effect of nanoparticles loaded with active components from Polygonum orientale L. against isoproterenol-induced myocardial ischemia in rats

In this study, nanoparticles loaded with active components from Polygonum orientale L. (PO), a traditional Chinese herb known for its anti-myocardial ischemic properties, were investigated for cardio-protective properties. Specifically, OVQ-Nanoparticles (OVQ-NPs) with Orientin (Ori), Vitexin (Vit), and Quercetin (Que) was obtained by double emulsion-solvent evaporation method. The OVQ-NPs exhibited a spherical shape, with a uniform size distribution of 136.77 ± 3.88 nm and a stable ζ-potential of -13.40 ± 2.24 mV. Notably, these nanoparticles exhibited a favorable sustained-release characteristic, resulting in an extended circulation time within the living organism. Consequently, the administration of these nanoparticles resulted in significant improvements in electrocardiograms and heart mass index of myocardial ischemic rats induced by isoproterenol, as well as decreased serum levels of CK, LDH, and AST. Furthermore, the results of histopathological examination, such as H&E staining and TUNEL staining, confirmed a reduced level of cardiac tissue pathology and apoptosis. Moreover, the quantification of biochemical indicators (SOD, MDA, GSH, NO, TNF-α, and IL-6) demonstrated that OVQ-NPs effectively mitigated myocardial ischemia by regulating oxidative stress and inflammatory pathways. In conclusion, OVQ-NPs demonstrate promising therapeutic potential as an intervention for myocardial ischemia, providing a new perspective on traditional Chinese medicine treatment in this area.

Microfluidic-assisted formulation of cell membrane-camouflaged anisotropic nanostructures

Anisotropic gold (Au) nanostructures have been widely explored for various nanomedicine applications. While these nanomaterials have shown great promise for disease theranostics, particularly for cancer diagnosis and treatment, the utilization and clinical translation of anisotropic Au nanostructures have been limited by their high phagocytic uptake and clearance and low cancer targeting specificity. Numerous efforts have thus been made toward mitigating these challenges. Many conventional strategies, however, rely on all-synthetic materials, involve complex chemical processes, or have low product throughput and reproducibility. Herein, by integrating cell membrane coating and microfluidic technologies, a high-throughput bioinspired approach for synthesizing biomimetic anisotropic Au nanostructures with minimized phagocytic uptake and improved cancer cell targeting is reported. Through continuous hydrodynamic flow focusing, mixing, and sonication, Au nanostructures are encapsulated within the macrophage and cancer cell membrane vesicles effectively. The fabricated nanostructures are uniform and highly stable in serum. Importantly, the macrophage membrane vesicle-encapsulated Au nanostructures can be preferentially internalized by breast cancer cells, but not by macrophages. Overall, this study has demonstrated the feasibility of employing an integrated microfluidic-sonication technique to formulate uniform and highly stable biomimetic anisotropic nanostructures for enhanced cancer theranostic applications.

Decoding Nanomaterial-Biosystem Interactions through Machine Learning

The interactions between biosystems and nanomaterials regulate most of their theranostic and nanomedicine applications. These nanomaterial-biosystem interactions are highly complex and influenced by a number of entangled factors, including but not limited to the physicochemical features of nanomaterials, the types and characteristics of the interacting biosystems, and the properties of the surrounding microenvironments. Over the years, different experimental approaches coupled with computational modeling have revealed important insights into these interactions, although many outstanding questions remain unanswered. The emergence of machine learning has provided a timely and unique opportunity to revisit nanomaterial-biosystem interactions and to further push the boundary of this field. This minireview highlights the development and use of machine learning to decode nanomaterial-biosystem interactions and provides our perspectives on the current challenges and potential opportunities in this field.

The interaction between particles and vascular endothelium in blood flow

Particle-based drug delivery systems have shown promising application potential to treat human diseases; however, an incomplete understanding of their interactions with vascular endothelium in blood flow prevents their inclusion into mainstream clinical applications. The flow performance of nano/micro-sized particles in the blood are disturbed by many external/internal factors, including blood constituents, particle properties, and endothelium bioactivities, affecting the fate of particles in vivo and therapeutic effects for diseases. This review highlights how the blood constituents, hemodynamic environment and particle properties influence the interactions and particle activities in vivo. Moreover, we briefly summarized the structure and functions of endothelium and simulated devices for studying particle performance under blood flow conditions. Finally, based on particle-endothelium interactions, we propose future opportunities for novel therapeutic strategies and provide solutions to challenges in particle delivery systems for accelerating their clinical translation. This review helps provoke an increasing in-depth understanding of particle-endothelium interactions and inspires more strategies that may benefit the development of particle medicine.

Dual-targeting tigecycline nanoparticles for treating intracranial infections caused by multidrug-resistant Acinetobacter baumannii

Multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) is a formidable pathogen responsible for severe intracranial infections post-craniotomy, exhibiting a mortality rate as high as 71%. Tigecycline (TGC), a broad-spectrum antibiotic, emerged as a potential therapeutic agent for MDR A. baumannii infections. Nonetheless, its clinical application was hindered by a short in vivo half-life and limited permeability through the blood-brain barrier (BBB). In this study, we prepared a novel core-shell nanoparticle encapsulating water-soluble tigecycline using a blend of mPEG-PLGA and PLGA materials. This nanoparticle, modified with a dual-targeting peptide Aβ11 and Tween 80 (Aβ11/T80@CSs), was specifically designed to enhance the delivery of tigecycline to the brain for treating A. baumannii-induced intracranial infections. Our findings demonstrated that Aβ11/T80@CSs nanocarriers successfully traversed the BBB and effectively delivered TGC into the cerebrospinal fluid (CSF), leading to a significant therapeutic response in a model of MDR A. baumannii intracranial infection. This study offers initial evidence and a platform for the application of brain-targeted nanocarrier delivery systems, showcasing their potential in administering water-soluble anti-infection drugs for intracranial infection treatments, and suggesting promising avenues for clinical translation.

Engineering poly(ethylene glycol) particles for targeted drug delivery

Poly(ethylene glycol) (PEG) is considered to be the "gold standard" among the stealth polymers employed for drug delivery. Using PEG to modify or engineer particles has thus gained increasing interest because of the ability to prolong blood circulation time and reduce nonspecific biodistribution of particles in vivo, owing to the low fouling and stealth properties of PEG. In addition, endowing PEG-based particles with targeting and drug-loading properties is essential to achieve enhanced drug accumulation at target sites in vivo. In this feature article, we focus on recent work on the synthesis of PEG particles, in which PEG is the main component in the particles. We highlight different synthesis methods used to generate PEG particles, the influence of the physiochemical properties of PEG particles on their stealth and targeting properties, and the application of PEG particles in targeted drug delivery.

Single-Cell Diagnosis of Cancer Drug Resistance through the Differential Endocytosis of Nanoparticles between Drug-Resistant and Drug-Sensitive Cancer Cells

Single-cell diagnosis of cancer drug resistance is highly relevant for cancer treatment, as it can be used to identify the subpopulations of drug-resistant cancer cells, reveal the sensitivity of cancer cells to treatment, and monitor the progress of cancer drug resistance. However, simple and effective methods for cancer drug resistance detection at the single-cell level are still lacking in laboratory and clinical studies. Inspired by the fact that nanoparticles with diverse physicochemical properties would generate distinct and specific interactions with drug-resistant and drug-sensitive cancer cells, which have distinctive molecular signatures, here, we have synthesized a library of fluorescent nanoparticles with various sizes, surface charges, and compositions (SiO2 nanoparticles (SNPs), organic PS-co-PAA nanoparticles (ONPs), and ZIF-8 nanoparticles (ZNPs)), thus demonstrating that the composition has a critical influence on the interaction of nanoparticles with drug-resistant cancer cells. Furthermore, the clathrin/caveolae-independent endocytosis of ZNPs together with the P-glycoprotein-related decreased cell membrane fluidity resulted in a lower cellular accumulation of ZNPs in drug-resistant cancer cells, consequently causing the distinct cellular accumulation of ZNPs between the drug-resistant and drug-sensitive cancer cells. This difference was further quantified by detecting the fluorescence signals generated by the accumulation of nanoparticles at the single-cell level via flow cytometry. Our findings provide another insight into the nanoparticle-cell interactions and offer a promising platform for the diagnosis of cancer drug resistance of various cancer cells and clinical cancer samples at the single-cell level.

Polyphosphazene nanodrugs for targeting delivery and inflammation responsive release of curcumin to treat acute lung injury by effectively inhibiting cytokine storms

An excessive inflammatory response induced by cytokine storms is the primary reason for the deterioration of patients with acute lung injury (ALI). Though natural polyphenols such as curcumin (CUR) have anti-inflammation activity for ALI treatment, they often have limited efficacy due to their poor solubility in water and oxidising tendency. This study investigates a highly cross-linked polyphosphazene nano-drug (PHCH) developed by copolymerisation of CUR and acid-sensitive units (4-hydroxy-benzoic acid (4-hydroxy-benzylidene)-hydrazide, D-HBD) with hexachlorotripolyphosphonitrile (HCCP) for improved treatment of ALI. PHCH can prolong the blood circulation time and targeted delivery into lung inflammation sites by enhancing CUR's water dispersion and anti-oxidant properties. PHCH also demonstrates the inflammation-responsive release of CUR in an inflammation environment due to the acid-responsive degradation of hydrazine bonds and triphosphonitrile rings in PHCH. Therefore, PHCH has a substantial anti-inflammation activity for ALI treatment by synergistically improving CUR's water-solubility, bioavailability and biocompatibility. As expected, PHCH attenuates the cytokine storm syndrome and alleviates inflammation in the infected cells and tissues by down-regulating several critical inflammatory cytokines (TNF-α, IL-1β, and IL-8). PHCH also decreases the expression of p-p65 and C-Caspase-1, inhibiting NLRP3 inflammasomes and suppressing NF-κB signalling pathways. The administrated mice experiments confirmed that PHCH accumulation was enhanced in lung tissue and showed the efficient scavenging ability of reactive oxygen species (ROS), effectively blocking the cytokine storm and alleviating inflammatory damage in ALI. This smart polyphosphazene nano-drug with targeting delivery property and inflammation-responsive release of curcumin has excellent potential for the clinical treatment of various inflammatory diseases, including ALI.

Recent advances of smart materials for ocular drug delivery

Owing to the variety and complexity of ocular diseases and the natural ocular barriers, drug therapy for ocular diseases has significant limitations, such as poor drug targeting to the site of the disease, poor drug penetration, and short drug retention time in the vitreous body. With the development of biotechnology, biomedical materials have reached the "smart" stage. To date, despite their inability to overcome all the aforementioned drawbacks, a variety of smart materials have been widely tested to treat various ocular diseases. This review analyses the most recent developments in multiple smart materials (inorganic particles, polymeric particles, lipid-based particles, hydrogels, and devices) to treat common ocular diseases and discusses the future directions and perspectives regarding clinical translation issues. This review can help researchers rationally design more smart materials for specific ocular applications.

Curcumin-Containing Polyphosphazene Nanodrug for Anti-Inflammation and Nerve Regeneration to Improve Functional Recovery After Spinal Cord Injury

The microenvironment of excessive inflammation and the activation of apoptotic signals are primary barriers to neurological recovery following spinal cord injury (SCI). Thus, long-lasting anti-inflammation has become an effective strategy to navigate SCI. Herein, a curcumin (CUR)-containing nanosystem (FCTHPC) with high drug loading efficiency was reported via assembling hydrophobic CUR into cross-linked polyphosphazene (PPZ), and simultaneous loading and coordinating with porous bimetallic polymers for greatly enhanced the water-solubility and biocompatibility of CUR. The nanosystem is noncytotoxic when directing its biological activities. By inhibiting the expression of pro-inflammatory factors (IL-1β, TNF-α and IL-6) and apoptotic proteins (C-caspase-3 and Bax/Bcl-2), which may be accomplished by activating the Wnt/β-catenin pathway, the versatile FCTHPC can significantly alleviate the damage to tissues and cells caused by inflammation and apoptosis in the early stage of SCI. In addition, the long-term in vivo studies had demonstrated that FCTHPC could effectively inhibit the formation of glial scars, and simultaneously promote nerve regeneration and myelination, leading to significant recovery of spinal cord function. This study emphasises the promise of the biocompatible CUR-based nanosystem and provides a fresh approach to effectively treat SCI.

Long-circulating gambogic acid-loaded nanodiamond composite nanosystem with inhibition of cell migration for tumor therapy

Herein, ultra dispersed and stably suspended nanodiamonds (NDs) were demonstrated to have a high load capacity, sustained release, and ability to serve as a biocompatible vehicle for delivery anticancer drugs. NDs with size of 50-100 nm exhibited good biocompatibility in normal human liver (L-02) cells. In particular, 50 nm ND not only promoted the noticeable proliferation of the L-02 cells but also can effectively inhibited the migration of human liver carcinoma (HepG2) cells. The gambogic acid-loaded nanodiamond (ND/GA) complex assembled by π-π stacking exhibits ultrasensitive and apparent suppression efficiency on the proliferation of HepG2 cells through high internalization and less efflux compared to free GA. More importantly, the ND/GA system can significantly increase the intracellular reactive oxygen species (ROS) levels in HepG2 cells and thus induce the cell apoptosis. The increase in intracellular ROS levels causes damage to the mitochondrial membrane potential (MMP) and activates cysteinyl aspartate specific proteinase 3 (Caspase-3) and cysteinyl aspartate specific proteinase 9 (Caspase-9), which leads to the occurrence of apoptosis. In vivo experiments also confirmed that the ND/GA complex has a much higher anti-tumor capability than free GA. Thus, the current ND/GA system is promising for cancer therapy.

Dispersion Performances of Naphthalimides Doped in Dual Temperature- and pH-Sensitive Poly (N-Isopropylacrylamide-co-acrylic Acid) Shell Assembled with Vinyl-Modified Mesoporous SiO2 Core for Fluorescence Cell Imaging

Developing effective intelligent nanocarriers is highly desirable for fluorescence imaging and therapeutic applications but remains challenging. Using a vinyl-grafted BMMs (bimodal mesoporous SiO₂ materials) as a core and PAN ((2-aminoethyl)-6-(dimethylamino)-1H-benzo[de]isoquinoline-1,3(2H)-dione))-dispersed dual pH/thermal-sensitive poly(N-isopropylacrylamide-co-acrylic acid) as a shell, PAN@BMMs with strong fluorescence and good dispersibility were prepared. Their mesoporous features and physicochemical properties were extensively characterized via XRD patterns, N₂ adsorption-desorption analysis, SEM/TEM images, TGA profiles, and FT-IR spectra. In particular, their mass fractal dimension (d_m) features based on SAXS patterns combined with fluorescence spectra were successfully obtained to evaluate the uniformity of the fluorescence dispersions, showing that the d_m values increased from 2.49 to 2.70 with an increase of the AN-additive amount from 0.05 to 1%, along with the red shifting of their fluorescent emission wavelength from 471 to 488 nm. The composite (PAN@BMMs-I-0.1) presented a densification trend and a slight decrease in peak (490 nm) intensity during the shrinking process. Its fluorescent decay profiles confirmed two fluorescence lifetimes of 3.59 and 10.62 ns. The low cytotoxicity obtained via in vitro cell survival assay and the efficient green imaging performed via HeLa cell internalization suggested that the smart PAN@BMM composites are potential carriers for in vivo imaging and therapy.

Carboxyl PEGylation of magnetic nanoparticles as antithrombotic and thrombolytic agents by calcium binding

Known to be biocompatible and hemocompatible, polyethylene glycol (PEG) has been widely used as anti-fouling coating of biomaterials. Nanoparticles coated with functionalized PEG were also investigated for their nano-cell interactions, but seldomly on the coagulation system, especially with platelets. Both experiments and molecular dynamic simulations indicate that terminal carboxylation of PEG promotes its binding with calcium, especially in the ionized form, which makes it potential anticoagulants. Further, the carboxyl PEGylated magnetic nanoparticle (HOOC-PEG₂₀₀₀-MNP) exhibits significantly increased anticoagulant and antiplatelet properties, by entering the open canalicular system (OCS) of human platelets and binding with the cytoplasmic calcium ions. HOOC-PEG₂₀₀₀-MNP also acts as effective thrombolytic agents in dissolving mature blood clots under oscillating magnetic field both in vitro and in vivo. Therefore, the carboxyl PEGylated magnetic nanoparticles are prototype agents for antithrombotic and thrombolytic therapies and provide a versatile platform for targeted and effective treatments of acute cardiovascular diseases.

Lutein-loaded chitosan/alginate-coated Fe3O4 nanoparticles as effective targeted carriers for breast cancer treatment

Magnetic drug targeting can be a strategy for effectively delivering phytochemicals in cancer treatment. Here, we demonstrate the benefit of magnetic targeting with superparamagnetic iron oxide nanoparticles for cytotoxicity enhancement of lutein (LUT) against breast cancer cells. Fabrication of LUT-loaded chitosan/alginate iron oxide nanoparticles (LUT-CS/Alg-Fe₃O₄-NPs) was optimized by a statistical approach using response surface methodology based on the Box-Behnken design. The optimized LUT-CS/Alg-Fe₃O₄-NPs with a balance among LUT concentration, copolymer coating, and iron ion concentration exhibited controlled size, narrow size distribution, better crystallinity, excellent saturation magnetization, and sustained-release profile. The negligible magnetic coercivity and remanent magnetization confirmed the superparamagnetism of the prepared NPs. The optimized LUT-CS/Alg-Fe₃O₄-NPs were biocompatible while exhibiting a significantly enhanced cytotoxicity towards breast cancer MCF-7 cells upon exposure to a permanent magnet compared to free LUT with a 4-fold increase, suggesting the potential of LUT-CS/Alg-Fe₃O₄-NPs as magnetically targeted delivery for breast cancer.

Understanding the aggregation, consumption, distribution and accumulation of nanoparticles of polyvinyl chloride and polymethyl methacrylate in Ruditapes philippinarum

Plastic products have become an integral part of our life. A widespread usage, high stability, uncontrolled disposal and slow degradation of plastics in the environment led to the generation and accumulation of nanoparticles of polymers (NPs) in the marine environment. However, little is known about the aggregation, consumption and distribution of NPs from common polymers such as polyvinyl chloride (NP-PVC) and polymethyl methacrylate (NP-PMMA) inside marine animal physiologies. In the current study, two types of polymers (PVC and PMMA) × four exposure concentrations (1, 5, 15 and 25 mg/L) × four times (4, 8, 12 and 24 h) exposure studies were conducted to understand the consumption and distribution of luminescent NP-PVC (98.6 ± 17.6 nm) and NP-PMMA (111.9 ± 37.1 nm) in R. philippinarum. Under laboratory conditions, NP-PVC showed a higher aggregation rate than NP-PMMA in seawater within a period of 24 h. Aggregations of NPs increased with an increase in initial NP concentrations, leading to significant settling of nanoparticles within 24 h exposure. Such aggregation and settling of particles enhanced the consumption of NPs by benthic filter-feeding R. philippinarum at all exposure concentrations during 4 h exposure. More interestingly, NP-PVC and NP-PMMA were observed in large amounts in both liver and gills (22.6 % - 29.1 %) of the clams. Furthermore, NP-PVC was detected in most organs of R. philippinarum as compared to NP-PMMA. This study demonstrates that different polymers distribute and accumulate differently in the same biological model under laboratory exposure conditions based on their chemical nature.

Rare-earth orthovanadate nanoparticles trigger Ca2+-dependent eryptosis

Introduction. Rare-earth orthovanadate nanoparticles (ReVO₄:Eu³⁺, Re = Gd, Y or La) are promising agents for photodynamic therapy of cancer due to their modifiable redox properties. However, their toxicity limits their application.Objective. The aim of this research was to elucidate pro-eryptotic effects of GdVO₄:Eu³⁺and LaVO₄:Eu³⁺nanoparticles with identification of underlying mechanisms of eryptosis induction and to determine their pharmacological potential in eryptosis-related diseases.Methods. Blood samples (n= 9) were incubated for 24 h with 0-10-20-40-80 mg l^-1GdVO₄:Eu³⁺or LaVO₄:Eu³⁺nanoparticles, washed and used to prepare erythrocyte suspensions to analyze the cell membrane scrambling (annexin-V-FITC staining), cell shrinkage (forward scatter signaling), reactive oxygen species (ROS) generation through 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) staining and intracellular Ca²⁺levels via FLUO4 AM staining by flow cytometry. Internalization of europium-enabled luminescent GdVO₄:Eu³⁺and LaVO₄:Eu³⁺nanoparticles was assessed by confocal laser scanning microscopy.Results.Both nanoparticles triggered eryptosis at concentrations of 80 mg l^-1. ROS-mediated mechanisms were not involved in rare-earth orthovanadate nanoparticles-induced eryptosis. Elevated cytosolic Ca²⁺concentrations were revealed even at subtoxic concentrations of nanoparticles. LaVO₄:Eu³⁺nanoparticles increased intracellular calcium levels in a more pronounced way compared with GdVO₄:Eu³⁺nanoparticles. Our data disclose that the small-sized (15 nm) GdVO₄:Eu³⁺nanoparticles were internalized after a 24 h incubation, while the large-sized (∼30 nm) LaVO₄:Eu³⁺nanoparticles were localized preferentially around erythrocytes.Conclusions.Both internalized GdVO₄:Eu³⁺and non-internalized LaVO₄:Eu³⁺nanoparticles (80 mg l^-1) promote eryptosis of erythrocytes after a 24 h exposurein vitrovia Ca²⁺signaling without involvement of oxidative stress. Eryptosis is a promising model for assessing nanotoxicity.

The culprits of superoxide dismutase inactivation under size-dependent stress of ultrafine carbon black: Superoxide anion, genotoxicity and protein corona

As a critical component of atmospheric ultrafine particulates, ultrafine carbon black (UFCB) brings great exposure risk to organisms. At present, the action pathway and activity regulation mechanism of UFCB on functional proteins in vivo are not clear, and the size-dependent effects of UFCB during this process need to be elucidated. Superoxide dismutase (SOD), one of the most applied biomarkers to assess the environmental impact of pollutants, plays crucial roles in resistance to oxidative stress. Here, based on the inactivation of SOD (84.79 %, 86.81 % and 91.70 %) in primary mouse hepatocytes exposed to UFCB (13 nm, 50 nm and 95 nm), oxidative stress, genotoxicity and protein molecular studies were employed to elucidate the inactivation mechanisms. Results showed that inhibition of UFCB-mediated superoxide anion (O₂^-) contributed to a decrease in SOD activity. Furthermore, the significant increase in 8-hydroxy-2-deoxyguanosine content and the comet tail formation indicated the occurrence of DNA damage, supporting that concomitant aberrant transcriptional and protein translational under gene regulation should be responsible for SOD inactivation. At the molecular level, the constricted backbone, reduced content of α-helix and fluorescence sensitization all demonstrated that the attachment-type binding of SOD on UFCB to form the 'protein corona' disrupted protein structure. Enzyme activity assays indicated that SOD backbone tightening and helix decay resulted in decreased activity, which should be another reason for intracellular SOD inactivation. More importantly, the particle sizes of UFCB exert powerful influences on SOD inactivation mechanisms. Smaller UFCB (13 nm) induced more severe O₂^- inhibition and DNA damage, while UFCB_50nm with the best dispersity bound more SOD and induced stronger molecular toxicity, which are their different strengths in stressing SOD inactivation in hepatocytes. Our findings provide novel insights for exploring functional proteins activity and underscore a potentially size-dependent risk of nanoparticles.

Precise engineering of disulfide bond-bridged prodrug nanoassemblies to balance antitumor efficacy and safety

Prodrug-based nanoassemblies, which combine the merits of prodrug technology and nanocarriers, are regarded as promising platforms for cancer treatment. Notably, the chemical structure of prodrugs is closely associated with antitumor efficacy and safety, and the intrinsic relationships among them need further exploration. Herein, paclitaxel was conjugated with 2-octyldodecan-1-ol through different positions of disulfide bond to construct the prodrug nanoassemblies. Interestingly, the minor differences in chemical structure not only dominated the assembly performance and drug release of nanoassemblies, but also significantly impacted the pharmacokinetics, antitumor efficacy, and safety. It was worth noting that prodrug nanoassemblies with one carbon atom between disulfide bond and ester bond had faster drug release and better antitumor effect, while prodrug nanoassemblies with three carbon atoms between disulfide bond and ester bond possessed moderate antitumor effect and better safety. Our findings illustrated the structure-function relationships of self-assembled prodrugs and provided a promising paradigm for the precise engineering of advanced prodrug nanoplatforms. STATEMENT OF SIGNIFICANCE: 1. The major effects of minor differences in prodrug chemical structure on pharmacodynamics and safety were explored, which had important clinical reference significance and value. 2. The in-depth exploration of structure-function relationships to balance efficacy and safety had important guiding significance for the design of prodrug nanoassemblies.

Polymersome-based protein drug delivery - quo vadis?

Protein-based therapeutics are an attractive alternative to established therapeutic approaches and represent one of the fastest growing families of drugs. While many of these proteins can be delivered using established formulations, the intrinsic sensitivity of proteins to denaturation sometimes calls for a protective carrier to allow administration. Historically, lipid-based self-assembled structures, notably liposomes, have performed this function. After the discovery of polymersome-based targeted drug-delivery systems, which offer manifold advantages over lipid-based structures, the scientific community expected that such systems would take the therapeutic world by storm. However, no polymersome formulations have been commercialised. In this review article, we discuss key obstacles for the sluggish translation of polymersome-based protein nanocarriers into approved pharmaceuticals, which include limitations imparted by the use of non-degradable polymers, the intricacies of polymersome production methods, and the complexity of the in vivo journey of polymersomes across various biological barriers. Considering this complex subject from a polymer chemist's point of view, we highlight key areas that are worthy to explore in order to advance polymersomes to a level at which clinical trials become worthwhile and translation into pharmaceutical and nanomedical applications is realistic.

Water-Soluble and Degradable Gelatin/Polyaniline Assemblies with a High Photothermal Conversion Efficiency for pH-Switchable Precise Photothermal Therapy

Photothermal therapy (PTT) is regarded as one of the potential techniques to replace surgery in the treatment of tumors. Polyaniline (PANI) shows better biocompatibility than inorganic reagents, which has been widely used in tumor photoacoustic (PA) imaging and PTT. However, the poor water solubility and nonspecific aggregation of PANI nanoparticles severely restricted their biomedical application. In addition, it is difficult to control the photothermal effect just on cancer cells. Herein, we develop tumor pH-responsive PANI-Gel/Cu assemblies, which can achieve targeted and precise ablation of tumors. Due to the high hydrophilicity of gelatin, the PANI-Gel/Cu assemblies show excellent dispersion in physiological solutions and long-term stability. By taking advantage of the self-doping effect between the carboxyl groups in gelatin and the imine part of the PANI skeleton, the photothermal characteristics of PANI-Gel/Cu assemblies can be promoted effectively by the acid tumor microenvironment, and the PA imaging of PANI-Gel/Cu assemblies can also be activated by tumor pH. Consequently, both the PTT enhancement and PA signal amplification can be triggered under a tumor microenvironment, and PANI-Gel/Cu assemblies can be targeted to cancer cells with the RGD sequences in their gelatin skeleton. In vivo imaging-guided PTT to A549 cancer shows precise treatment with little harm to normal cells, and PANI-Gel/Cu assemblies can disassemble into tiny particles (<15 nm) under laser irradiation. This work overcomes the intrinsic limitation of PANI materials, i.e., poor water solubility and nonspecific aggregation, meanwhile providing a pH-active PANI-based platform for precise and effective ablation of cancer.

In Situ Visualization of Dynamic Cellular Effects of Phospholipid Nanoparticles via High-Speed Scanning Ion Conductance Microscopy

Phospholipid nanoparticles have been actively employed for numerous biomedical applications. A key factor in ensuring effective and safe applications of these nanomaterials is the regulation of their interactions with target cells, which is significantly dependent on an in-depth understanding of the nanoparticle-cell interactions. To date, most studies investigating these nano-bio interactions have been performed under static conditions and may lack crucial real-time information. It is, however, noteworthy that the nanoparticle-cell interactions are highly dynamic. Consequently, to gain a deeper insight into the cellular effects of phospholipid nanoparticles, real-time observation of cellular dynamics after nanoparticle introduction is necessary. Herein, a proof-of-concept in situ visualization of the dynamic cellular effects of sub-100 nm phospholipid nanoparticles using high-speed scanning ion conductance microscopy (HS-SICM) is reported. It is revealed that upon introduction into the cellular environment, within a short timescale of hundreds of seconds, phospholipid nanoparticles can selectively modulate the edge motility and surface roughness of healthy fibroblast and cancerous epithelial cells. Furthermore, the dynamic deformation profiles of these cells can be selectively altered in the presence of phospholipid nanoparticles. This work is anticipated to further shed light on the real-time nanoparticle-cell interactions for improved formulation of phospholipid nanoparticles for numerous bioapplications.

Where Is Nano Today and Where Is It Headed? A Review of Nanomedicine and the Dilemma of Nanotoxicology

Worldwide nanotechnology development and application have fueled many scientific advances, but technophilic expectations and technophobic demands must be counterbalanced in parallel. Some of the burning issues today are the following: (1) Where is nano today? (2) How good are the communication and investment networks between academia/research and governments? (3) Is there any spotlight application for nanotechnology? Nanomedicine is a particular arm of nanotechnology within the healthcare landscape, focused on diagnosis, treatment, and monitoring of emerging (such as coronavirus disease 2019, COVID-19) and contemporary (including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer) diseases. However, it may only represent the bright side of the coin. In fact, in the recent past, the concept of nanotoxicology has emerged to address the dark shadows of nanomedicine. The nanomedicine field requires more nanotoxicological studies to identify undesirable effects and guarantee safety. Here, we provide an overall perspective on nanomedicine and nanotoxicology as central pieces of the giant puzzle of nanotechnology. First, the impact of nanotechnology on education and research is highlighted, followed by market trends and scientific output tendencies. In the next section, the nanomedicine and nanotoxicology dilemma is addressed through the interplay of in silico, in vitro, and in vivo models with the support of omics and microfluidic approaches. Lastly, a reflection on the regulatory issues and clinical trials is provided. Finally, some conclusions and future perspectives are proposed for a clearer and safer translation of nanomedicines from the bench to the bedside.

Designing high performance polymer nanocomposites by incorporating robustness-controlled polymeric nanoparticles: insights from molecular dynamics

Introducing polymeric nanoparticles into polymer matrices is an interesting topic, and the robustness of the polymeric nanoparticles is crucial for the properties of the polymer nanocomposites (PNCs). In this study, by incorporating star-shaped polymeric nanoparticles (SSPNs) into the polymer, the effect of the sphericity (η) and arm length (L) of the SSPNs on the mechanical properties of PNCs is systematically investigated, using a coarse-grained molecular dynamics simulation. In addition, the linear and spherical nanoparticles (NPs) are compared with SSPNs by fixing the approximate diameter and mass fraction of the NPs. The radial distribution function, the second virial coefficient, mean-squared displacement, bond autocorrelation function, and primitive path analysis are employed to systematically characterize the structure and dynamics of these new PNCs. It is found that the dispersion of the NPs is enhanced with the increase of η, and the entanglement density reaches maximum, which both contribute to the greatest mechanical reinforcing effect. More significantly, it is found that the classical Payne effect, namely the storage as a function of the strain amplitude, decreases remarkably, and with a much smaller loss factor for these SSPN filled polymer nanocomposites, compared to conventional PNCs filled with rigid NPs. Furthermore, the change of the arm length of the SSPNs is found to exhibit the same effect on the mechanical and viscoelastic properties, as the variation of the number of the arms. In general, this work shows that these new SSPN filled polymer nanocomposites can exceed conventional PNCs, by manipulating the robustness of the SSPNs using, for example, the number and length of the arms. This research may provide guidelines for the investigation of the structure-property relationships of the topological structure of polymeric nanoparticles.

Mitochondria-targeted nanoplatforms for enhanced photodynamic therapy against hypoxia tumor

Background

Photodynamic therapy (PDT) is a promising therapeutic modality that can convert oxygen into cytotoxic reactive oxygen species (ROS) via photosensitizers to halt tumor growth. However, hypoxia and the unsatisfactory accumulation of photosensitizers in tumors severely diminish the therapeutic effect of PDT. In this study, a multistage nanoplatform is demonstrated to overcome these limitations by encapsulating photosensitizer IR780 and oxygen regulator 3-bromopyruvate (3BP) in poly (lactic-co-glycolic acid) (PLGA) nanocarriers.

Results

The as-synthesized nanoplatforms penetrated deeply into the interior region of tumors and preferentially remained in mitochondria due to the intrinsic characteristics of IR780. Meanwhile, 3BP could efficiently suppress oxygen consumption of tumor cells by inhibiting mitochondrial respiratory chain to further improve the generation of ROS. Furthermore, 3BP could abolish the excessive glycolytic capacity of tumor cells and lead to the collapse of ATP production, rendering tumor cells more susceptible to PDT. Successful tumor inhibition in animal models confirmed the therapeutic precision and efficiency. In addition, these nanoplatforms could act as fluorescence (FL) and photoacoustic (PA) imaging contrast agents, effectuating imaging-guided cancer treatment.

Conclusions

This study provides an ideal strategy for cancer therapy by concurrent oxygen consumption reduction, oxygen-augmented PDT, energy supply reduction, mitochondria-targeted/deep-penetrated nanoplatforms and PA/FL dual-modal imaging guidance/monitoring. It is expected that such strategy will provide a promising alternative to maximize the performance of PDT in preclinical/clinical cancer treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01196-6.

A review of the berberine natural polysaccharide nanostructures as potential anticancer and antibacterial agents

Despite the promising medicinal properties, berberine (BBR), due to its relatively poor solubility in plasma, low bio-stability and limited bioavailability is not used broadly in clinical stages. Due to these drawbacks, drug delivery systems (DDSs) based on nanoscale natural polysaccharides, are applied to address these concerns. Natural polymers are biodegradable, non-immunogenic, biocompatible, and non-toxic agents that are capable of trapping large amounts of hydrophobic compounds in relatively small volumes. The use of nanoscale natural polysaccharide improves the stability and pharmacokinetics of the small molecules and, consequently, increases the therapeutic effects and reduces the side effects of the small molecules. Therefore, this paper presents an overview of the different methods used for increasing the BBR solubility and bioavailability. Afterwards, the pharmacodynamic and pharmacokinetic of BBR nanostructures were discussed followed by the introduction of natural polysaccharides of plant (cyclodextrines, glucomannan), the shells of crustaceans (chitosan), and the cell wall of brown marine algae (alginate)-based origins used to improve the dissolution rate of poorly soluble BBR and their anticancer and antibacterial properties. Finally, the anticancer and antibacterial mechanisms of free BBR and BBR nanostructures were surveyed. In conclusion, this review may pave the way for providing some useful data in the development of BBR-based platforms for clinical applications.

Recent Advances in AIEgen-Based Photodynamic Therapy and Immunotherapy

Cancer, one of the leading causes of death, has seriously threatened public health. However, there is still a lack of effective treatments. Nowadays, photodynamic therapy (PDT), relying on photosensitizers to trigger the generation of reactive oxygen species (ROS) for killing cancer cells, has been emerging as a noninvasive anti-cancer strategy. To enhance the overall anti-cancer efficacy of PDT, various approaches including molecular design and combination with other therapeutic techniques have been proposed and implemented. Especially, photodynamic immunotherapy that can effectively evoke the body's immune response has attracted much attention. Recently, a class of photosensitizers with aggregation-induced emission (AIE) character have shown unique promises, taking advantage of their profound fluorescence and ROS-generating ability in the aggregation state. Despite the promising results demonstrated by several groups, the associated studies are few and the mechanism of such AIEgen-based photodynamic immunotherapy has not been fully understood. This review discusses the recent advances in the AIEgen-based enhanced PDT with a special focus on the AIE photosensitizers for photodynamic immunotherapy, aiming to inspire more opportunities for in-depth investigation of the working principles in this emerging anti-cancer approach.

Recent Advances in Hypoxia-Overcoming Strategy of Aggregation-Induced Emission Photosensitizers for Efficient Photodynamic Therapy

Hypoxia is an inherent physiologic barrier in the microenvironment of solid tumor and has badly restricted the therapeutic effect of photodynamic therapy (PDT). Meanwhile, the photosensitizer (PS) agents used for PDT applications regularly encounter the tiresome aggregation-caused quenching effect that seriously decreases the production efficiency of cytotoxic reactive oxygen species. The aggregation-induced emission (AIE) PSs with antiquenching characteristics in the aggregate state are considered as a promising tool for achieving highly efficient PDT applications, and plenty of studies have widely demonstrated their advantages in various diseases. Herein, the recent progress of AIE PSs in the battle of antitumor hypoxia issue is summarized and the practical molecular principles of hypoxia-overcoming AIE PSs are highlighted. According to the hypoxia-overcoming mechanism, these representative cases are divided into low O₂ -dependent (type I PDT) and O₂ -dependent tactics (mainly including O₂ -enrichment type II PDT and combination therapy). Furthermore, the underlying challenges and prospects of AIE PSs in hypoxia-overcoming PDT are proposed and thus expect to promote the next development of AIE PSs.

Differential Collective Cell Migratory Behaviors Modulated by Phospholipid Nanocarriers

Phospholipid nanocarriers have been widely explored for theranostic and nanomedicine applications. These amphiphilic nanocarriers possess outstanding cargo encapsulation efficiency, high water dispersibility, and excellent biocompatibility, which render them promising for drug delivery and bioimaging applications. While the biological applications of phospholipid nanocarriers have been well documented, the fundamental aspects of the phospholipid-cell interactions beyond cytotoxicity have been less investigated. In particular, the effect of phospholipid nanocarriers on collective cell behaviors has not been elucidated. Herein, we evaluate the interactions of phospholipid nanocarriers possessing different functional groups and sizes with normal and cancerous immortalized breast epithelial cell sheets with varying metastatic potential. Specifically, we examine the impact of nanocarrier treatments on the collective migratory dynamics of these cell sheets. We observe that phospholipid nanocarriers induce differential collective cell migratory behaviors, where the migration speed of normal and cancerous breast epithelial cell sheets is retarded and accelerated, respectively. To a certain extent, the nanocarriers are able to alter the migration trajectory of the cancerous breast epithelial cells. Furthermore, phospholipid nanocarriers could modulate the stiffness of the nuclei, cytoplasm, and cell-cell junctions of the breast epithelial cell sheets, remodel their actin filament arrangement, and regulate the expressions of the actin-related proteins. We anticipate that this work will further shed light on nanomaterial-cell interactions and provide guidelines for rational and safer designs and applications of phospholipid nanocarriers for cancer theranostics and nanomedicine.

Quercetin attenuates neurotoxicity induced by iron oxide nanoparticles

Iron oxide nanoparticles (IONPs) have been proposed as targeted carriers to deliver therapeutic molecules in the central nervous system (CNS). However, IONPs may damage neural tissue via free iron accumulation, protein aggregation, and oxidative stress. Neuroprotective effects of quercetin (QC) have been proven due to its antioxidant and anti-inflammatory properties. However, poor solubility and low bioavailability of QC have also led researchers to make various QC-involved nanoparticles to overcome these limitations. We wondered how high doses or prolonged treatment with quercetin conjugated superparamagnetic iron oxide nanoparticles (QCSPIONs) could improve cognitive dysfunction and promote neurogenesis without any toxicity. It can be explained that the QC inhibits protein aggregation and acts against iron overload via iron-chelating activity, iron homeostasis genes regulation, radical scavenging, and attenuation of Fenton/Haber-Weiss reaction. In this review, first, we present brain iron homeostasis, molecular mechanisms of iron overload that induced neurotoxicity, and the role of iron in dementia-associated diseases. Then by providing evidence of IONPs neurotoxicity, we discuss how QC neutralizes IONPs neurotoxicity, and finally, we make a brief comparison between QC and conventional iron chelators. In this review, we highlight that QC as supplementation and especially in conjugated form reduces iron oxide nanoparticles neurotoxicity in clinical application.

Kinetic stability modulation of polymeric nanoparticles for enhanced detection of influenza virus via penetration of viral fusion peptides

Specific interactions between viruses and host cells provide essential insights into material science-based strategies to combat emerging viral diseases. pH-triggered viral fusion is ubiquitous to multiple viral families and is important for understanding the viral infection cycle. Inspired by this process, virus detection has been achieved using nanomaterials with host-mimetic membranes, enabling interactions with amphiphilic hemagglutinin fusion peptides of viruses. Most research has been on designing functional nanoparticles with fusogenic capability for virus detection, and there has been little exploitation of the kinetic stability to alter the ability of nanoparticles to interact with viral membranes and improve their sensing performance. In this study, a homogeneous fluorescent assay using self-assembled polymeric nanoparticles (PNPs) with tunable responsiveness to external stimuli is developed for rapid and straightforward detection of an activated influenza A virus. Dissociation of PNPs induced by virus insertion can be readily controlled by varying the fraction of hydrophilic segments in copolymers constituting PNPs, giving rise to fluorescence signals within 30 min and detection of various influenza viruses, including H9N2, CA04(H1N1), H4N6, and H6N8. Therefore, the designs demonstrated in this study propose underlying approaches for utilizing engineered PNPs through modulation of their kinetic stability for direct and sensitive identification of infectious viruses.

Effects of polyethylene glycol on the surface of nanoparticles for targeted drug delivery

The rapid development of drug nanocarriers has benefited from the surface hydrophilic polymers of particles, which has improved the pharmacokinetics of the drugs. Polyethylene glycol (PEG) is a kind of polymeric material with unique hydrophilicity and electrical neutrality. PEG coating is a crucial factor to improve the biophysical and chemical properties of nanoparticles and is widely studied. Protein adherence and macrophage removal are effectively relieved due to the existence of PEG on the particles. This review discusses the PEGylation methods of nanoparticles and related techniques that have been used to detect the PEG coverage density and thickness on the surface of the nanoparticles in recent years. The molecular weight (MW) and coverage density of the PEG coating on the surface of nanoparticles are then described to explain the effects on the biophysical and chemical properties of nanoparticles.

Incorporating spin-orbit coupling promoted functional group into an enhanced electron D-A system: A useful designing concept for fabricating efficient photosensitizer and imaging-guided photodynamic therapy

Intersystem crossing (ISC) is of great significance in photochemistry, and has a decisive influence on the properties of photosensitizers (PSs) for use in photodynamic therapy (PDT). However, the rationally design PSs with efficient ISC processes to implement superb reactive oxygen species (ROS) production is still a very challenging work. In this contribution, we described how a series of high-performance PSs were constructed through electron acceptor and donor engineering by integrating the smaller singlet-triplet energy gap (ΔE_ST) and larger spin-orbit coupling (SOC)-beneficial functional groups into the PS frameworks. Among the yielded various PSs, TaTIC was confirmed as the best candidate for application in PDT, which was due to its most outstanding ROS generation capability, bright near-infrared (NIR) fluorescence with peak over 840 nm, as well as desired aggregation-induced emission (AIE) features. Importantly, the ROS generation efficiency of TaTIC was even superior to that of some popularly used PSs, including the most reputable PS of Rose Bengal. In order to further extend therapeutic applications, TaTIC was encapsulated with biocompatible amphiphilic matrix and formulated into water-dispersed nanoparticles (NPs). More excitedly, the as-prepared TaTIC NPs gave wonderful PDT performance on tumor-bearing mouse model, actualizing complete tumor elimination outcomes. Coupled with excellent biosecurity, TaTIC NPs would be a promising theranostic agent for practical clinical application.

Toolbox of Biodegradable Dendritic (Poly glycerol sulfate)-SS-poly(ester) Micelles for Cancer Treatment: Stability, Drug Release, and Tumor Targeting

In this paper, we present well-defined dPGS-SS-PCL/PLGA/PLA micellar systems demonstrating excellent capabilities as a drug delivery platform in light of high stability and precise in vitro and in vivo drug release combined with active targetability to tumors. These six amphiphilic block copolymers were each targeted in two different molecular weights (8 or 16 kDa) and characterized using ¹H NMR, gel permeation chromatography (GPC), and elemental analysis. The block copolymer micelles showed monodispersed size distributions of 81-187 nm, strong negative charges between -52 and -41 mV, and low critical micelle concentrations (CMCs) of up to 1.13-3.58 mg/L (134-527 nM). The serum stability was determined as 94% after 24 h. The drug-loading efficiency for Sunitinib ranges from 38 to 83% (8-17 wt %). The release was selectively triggered by glutathione (GSH) and lipase, reaching 85% after 5 days, while only 20% leaching was observed under physiological conditions. Both the in vitro and in vivo studies showed sustained release of Sunitinib over 1 week. CCK-8 assays on HeLa lines demonstrated the high cell compatibility (1 mg/mL, 94% cell viability, 48 h) and the high cancer cell toxicity of Sunitinib-loaded micelles (IC₅₀ 2.5 μg/mL). By in vivo fluorescence imaging studies on HT-29 tumor-bearing mice, the targetability of dPGS_7.8-SS-PCL_7.8 enabled substantial accumulation in tumor tissue compared to nonsulfated dPG_3.9-SS-PCL_7.8. As a proof of concept, Sunitinib-loaded dPGS-SS-poly(ester) micelles improved the antitumor efficacy of the chemotherapeutic. A tenfold lower dosage of loaded Sunitinib led to an even higher tumor growth inhibition compared to the free drug, as demonstrated in a HeLa human cervical tumor-bearing mice model. No toxicity for the organism was observed, confirming the good biocompatibility of the system.

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

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

Programmable Engineering of DNA-AuNP Encoders Integrated Multimodal Coupled Analysis for Precision Discrimination of Multiple Metal Ions

A cross-responsive strategy (CRS) based on gold nanoparticles (AuNPs) through attaching various recognition receptors on the surface of AuNPs for identifying multiple analytes is presented, and the detection throughput and overall identification accuracy are improved. However, the CRS's recognition receptor cannot get comprehensive information from the target analytes limited in number and type, which determines the overall identification accuracy. Therefore, the practicability of the CRS runs into a bottleneck. Herein, we report a programmable DNA-AuNP encoder combined with a multimodal coupled analysis algorithm for high-throughput detection and accurate analysis of multiple metal ions. The programmable DNA-AuNP encoder breaks through the limitation of the recognition receptor's quantity. Furthermore, the multimodal signals from target metal ion-induced DNA-AuNP aggregation are related to and observed in the ultraviolet absorbance spectrum, surface potential, and particle diameter. The multimodal coupled analysis algorithm can reflect comprehensive information on the target analyte more completely. Finally, this study provides a highly generic tool for the cross-responsive strategy.

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

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

Harnessing Endogenous Stimuli for Responsive Materials in Theranostics

Materials that respond to endogenous stimuli are being leveraged to enhance spatiotemporal control in a range of biomedical applications from drug delivery to diagnostic tools. The design of materials that undergo morphological or chemical changes in response to specific biological cues or pathologies will be an important area of research for improving efficacies of existing therapies and imaging agents, while also being promising for developing personalized theranostic systems. Internal stimuli-responsive systems can be engineered across length scales from nanometers to macroscopic and can respond to endogenous signals such as enzymes, pH, glucose, ATP, hypoxia, redox signals, and nucleic acids by incorporating synthetic bio-inspired moieties or natural building blocks. This Review will summarize response mechanisms and fabrication strategies used in internal stimuli-responsive materials with a focus on drug delivery and imaging for a broad range of pathologies, including cancer, diabetes, vascular disorders, inflammation, and microbial infections. We will also discuss observed challenges, future research directions, and clinical translation aspects of these responsive materials.