Advances of nanoparticles as drug delivery systems for disease diagnosis and treatment

Decades have passed since the first nanoparticles-base medicine was approved for human cancer treatment, and the research and development of nanoparticles for drug delivery are always undergoing.Nowadays, the significant advances complicate nanoparticles’ branches, including liposomes, solid lipid nanoparticles, inorganic nanoparticles, micelles, nanovaccines and nano-antibodies, etc. These nanoparticles show numerous capabilities in treatment and diagnosis of stubborn diseases like cancer and neurodegenerative diseases, emerging as novel drug carriers or therapeutic agents in future. In this review, the complicated branches of nanoparticles are classified and summarized, with their property and functions concluded. Besides, there are also some delivery strategies that make nanoparticles smarter and more efficient in drug delivery, and frontiers in these strategies are also summarized in this review. Except these excellent works in newly-produced drug delivery nanoparticles, some points of view and future expectations are made in the end.

Recent advances in targeted stimuli-responsive nano-based drug delivery systems combating atherosclerosis

Atherosclerosis(AS), mainly caused by the changed immune system functions and inflammation, is the central pathogenesis of cardiovascular disease, which is a leading cause of death in the world. In modern medicine, the development of carriers precisely delivering the therapeutic agents to the target sites is the primary goal, which could minimize the potential adverse effects and be more effective in treating lesions. Due to the precise location, real-time monitoring, AS microenvironment response, and low toxicity, stimuli-responsive nano-based drug delivery systems(NDDSs) have been a promising approach in AS treatments. Herein, we will systematically summarize the recent advances in stimuli-responsive NDDSs for AS treatment, including internal stimuli(reactive oxygen species, enzyme, shear stress, and pH) and external stimuli(light, ultrasound, and magnetism) responsive NDDSs. Besides, we will also summarize in detail the classification of stimuli-responsive NDDSs for AS, such as organic NDDSs(e.g., lipid-based and polymer-based nanomaterials), inorganic NDDSs(e.g., metal-based nanoparticles and nonmetallic nanomaterials), and composite multifunctional NDDSs. Finally, the critical challenges and prospects of this field will also be proposed and discussed.

Iron-based and BRD_(4)-downregulated strategy for amplified ferroptosis based on pH-sensitive/NIR-Ⅱ-boosted nano-matchbox

Ferroptosis(FPT),a novel form of programmed cell death,is characterized by overwhelming iron/reactive oxygen species(ROS)-dependent accumulation of lipid peroxidation(LPO).However,the insufficiency of endogenous iron and ROS level limited the FPT therapeutic efficacy to a large extent.To overcome this obstacle,the bromodomain-containing protein 4(BRD_(4))-inhibitor(+)-JQ1(JQ1)and iron-supplement ferric ammonium citrate(FAC)-loaded gold nanorods(GNRs)are encapsulated into the zeolitic imidazolate framework-8(ZIF-8)to form matchbox-like GNRs@JF/ZIF-8 for the amplified FPT therapy.The existence of matchbox(ZIF-8)is stable in physiologically neutral conditions but degradable in acidic environment,which could prevent the loaded agents from prematurely reacting.Moreover,GNRs as the drug-carriers induce the photothermal therapy(PTT)effect under the irradiation of near-infraredⅡ(NIR-Ⅱ)light owing to the absorption by localized surface plasmon resonance(LSPR),while the hyperthermia also boosts the JQ1 and FAC releasing in the tumor microenvironment(TME).On one hand,the FAC-induced Fenton/Fenton-like reactions in TME can simultaneously generate iron(Fe^(3+)/Fe^(2+))and ROS to initiate the FPT treatment by LPO elevation.On the other hand,JQ1 as a small molecule inhibitor of BRD_(4)protein can amplify FPT through downregulating the expression of glutathione peroxidase 4(GPX4),thus inhibiting the ROS elimination and leading to the LPO accumulation.Both in vitro and in vivo studies reveal that this p H-sensitive nano-matchbox achieves obvious suppression of tumor growth with good biosafety and biocompatibility.As a result,our study points out a PTT combined iron-based/BRD_(4)-downregulated strategy for amplified ferrotherapy which also opens the door of future exploitation of ferrotherapy systems.

4T1 cell membrane-derived biodegradable nanosystem for comprehensive interruption of cancer cell metabolism

Glycolysis inhibition can effectively block the energy supply and interrupt tumorigenesis in many types of cancers.However,when glycolysis is inhibited,tumor cells will break down glutamine as the raw material for the replenishment pathway to maintain the tricarboxylic acid cycle ensuring energy supply,therefore inducing ineffective interruption of metabolic.Herein,we designed glutamine transporter antagonist L-γ-glutamyl-p-nitroanilide(GPNA)loaded and 4T1 cancer cell membrane coated iridium oxide nanoparticles(IrO_(2)-GPNA@CCM)to realize a comprehensive inhibition of tumor energy supply which synergistically mediated by glycolysis and glutamine cycle.IrO_(2)NPs were used to catalyze the O_(2)generation by facilitating the decomposition of endogenous H_(2)O_(2)in tumor cells,which further downregulated the expression of HIF-1αand PI3K/pAKT to interrupt the generation of lactate.Meanwhile,the loaded GPNA was released under NIR irradiation to bind to alanine-serine-cysteine transporter(ASCT2)for glutamine uptake suppression,therefore realizing the comprehensive dysfunction of cell metabolism.Moreover,both in vitro and in vivo results convinced the thorough energy inhibition effect based on Ir O_(2)-GPNA@CCM NPs,which provided an inspiring strategy for future construction of tumor therapeutic regimen.

Rod-shape inorganic biomimetic mutual-reinforcing MnO2-Au nanozymes for catalysis-enhanced hypoxic tumor therapy

Biomimetic nanozymes possessing natural enzyme-mimetic activities have been extensively applied in nanocatalytic tumor therapy.However,engineering hybrid biomimetic nanozymes to achieve superior nanozyme activity remained to be an intractable challenge in hypoxic tumors.Herein,a rod-like biomimetic hybrid inorganic MnO2-Au nanozymes are developed,where MnO2 and ultrasmall Au nanoparticles(NPs)are successively deposited on the mesoporous silica nanorod to cooperatively improve the O2 content and thermal sensitivity of hypoxic solid tumors guided by multi-modal imaging.Under the catalyzing of MnO2,the intratumoral H2O2 is decomposed to greatly accelerate O2 generation,which could boost the curative effect of radiation therapy(RT)and further enhance the Au-catalyzed glucose oxidation.Mutually,the Au NPs can steadily and efficiently catalyze the oxidation of glucose in harsh tumor microenvironment,thus sensitizing tumor cells to thermal ablation for mild photothermal therapy and further promoting the catalytic efficiency of MnO2 with the self-supplied H2O2/H+.As a result,this mutual-reinforcing cycle can endow the nanoplatform with accelerated O2 generation,thus alleviating hypoxic environment and further boosting RT effect.Furthermore,acute glucose consuming can induce downregulation expression of heat shock protein(HSP),achieving starvation-promoted mild photothermal therapy.This synthesized hybrid nanozymes proves to be a versatile theranostic agent for nanocatalytic cancer therapy.

NIR-II driven plasmon-enhanced cascade reaction for tumor microenvironment-regulated catalytic therapy based on bio-breakable Au-Ag nanozyme

Emerging nanozymes with natural enzyme-mimicking catalytic activities have inspired extensive research interests due to their high stability,low cost,and simple preparation,especially in the field of catalytic tumor therapy.Here,bio-breakable nanozymes based on glucose-oxidase(GOx)-loaded biomimetic Au–Ag hollow nanotriangles(Au–Ag–GOx HTNs)are designed,and they trigger an near-infrared(NIR)-II-driven plasmon-enhanced cascade catalytic reaction through regulating tumor microenvironment(TME)for highly efficient tumor therapy.Firstly,GOx can effectively trigger the generation of gluconic acid(H+)and hydrogen peroxide(H2O2),thus depleting nutrients in the tumor cells as well as modifying TME to provide conditions for subsequent peroxidase(POD)-like activity.Secondly,NIR-II induced surface plasmon resonance can induce hot electrons to enhance the catalytic activity of Au–Ag–GOx HTNs,eventually boosting the generation of hydroxyl radicals(•OH).Interestingly,the generated H2O2 and H+can simultaneously induce the degradation of Ag nanoprisms to break the intact triangle nanostructure,thus promoting the excretion of Au–Ag–GOx HTNs to avoid the potential risks of drug metabolism.Overall,the NIR-II driven plasmon-enhanced catalytic mechanism of this bio-breakable nanozyme provides a promising approach for the development of nanozymes in tumor therapy.