Carrier-free nanodrugs with efficient drug delivery and release for cancer therapy:From intrinsic physicochemical properties to external modification

The considerable development of carrier-free nanodrugs has been achieved due to their high drug-loading capability,simple preparation method,and offering“all-in-one”functional platform features.However,the native defects of carrier-free nanodrugs limit their delivery and release behavior throughout the in vivo journey,which significantly compromise the therapeutic efficacy and hinder their further development in cancer treatment.In this review,we summarized and discussed the recent strategies to enhance drug delivery and release of carrier-free nanodrugs for improved cancer therapy,including optimizing the intrinsic physicochemical properties and external modification.Finally,the corresponding challenges that carrier-free nanodrugs faced are discussed and the future perspectives for its application are presented.We hope this review will provide constructive information for the rational design of more effective carrier-free nanodrugs to advance therapeutic treatment.

Codelivery of anti-CD47 antibody and chlorin e6 using a dual pH-sensitive nanodrug for photodynamic immunotherapy of osteosarcoma

Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.

Role of targeting ferroptosis as a component of combination therapy in combating drug resistance in colorectal cancer

Colorectal cancer(CRC)is a form of cancer that is often resistant to chemotherapy,targeted therapy,radiotherapy,and immunotherapy due to its genomic instability and inflammatory tumor microenvironment.Ferroptosis,a type of non-apoptotic cell death,is characterized by the accumulation of iron and the oxidation of lipids.Studies have revealed that the levels of reactive oxygen species and glutathione in CRC cells are significantly lower than those in healthy colon cells.Erastin has emerged as a promising candidate for CRC treatment by diminishing stemness and chemoresistance.Moreover,the gut,responsible for regulating iron absorption and release,could influence CRC susceptibility through iron metabolism modulation.Investigation into ferroptosis offers new insights into CRC pathogenesis and clinical management,potentially revolutionizing treatment approaches for therapy-resistant cancers.

Advances of nanotechnology applied to cancer stem cells

Cancer stem cells(CSCs)are a small proportion of the cells that exist in cancer tissues.They are considered to be the culprit of tumor genesis,development,drug resistance,metastasis and recurrence because of their self-renewal,proliferation,and differentiation potential.The elimination of CSCs is thus the key to cure cancer,and targeting CSCs provides a new method for tumor treatment.Due to the advantages of controlled sustained release,targeting and high biocompatibility,a variety of nanomaterials are used in the diagnosis and treatments targeting CSCs and promote the recognition and removal of tumor cells and CSCs.This article mainly reviews the research progress of nanotechnology in sorting CSCs and nanodrug delivery systems targeting CSCs.Furthermore,we identify the problems and future research directions of nanotechnology in CSC therapy.We hope that this review will provide guidance for the design of nanotechnology as a drug carrier so that it can be used in clinic for cancer therapy as soon as possible.

Intratympanic injection of hydrogel nanodrug for the prevention and treatment of sensorineural hearing loss

Safe and efficient drug delivery to the inner ear has always been the focus of prevention and treatment of sensorineural deafness.The rapid development of nanodrug delivery systems based on hydrogel has provided a new opportunity.Among them,thermo-sensitive hydrogels promote the development of new dosage form for intratympanic injection.This smart biomaterial could transform to semisolid phase when the temperature increased.Thermo-sensitive hydrogel nanodrug delivery system is expected to achieve safe,efficient,and sustained inner ear drug administration.This article introduces the key techniques and the latest progress in this field.

Tumor Microenvironment Cascade‑Responsive Nanodrug with Self‑Targeting Activation and ROS Regeneration for Synergistic Oxidation‑Chemotherapy

Carrier-free nanodrug with exceptionally high drug payload has attracted increasing attentions.Herein,we construct a pH/ROS cascade-responsive nanodrug which could achieve tumor acidity-triggered targeting activation followed by circularly amplified ROS-triggered drug release via positive-feedback loop.The di-selenide-bridged prodrug synthesized from vitamin E succinate and methotrexate(MTX)self-assembles into nanoparticles(VSeM);decorating acidity-cleavable PEG onto VSeM surface temporarily shields the targeting ability of MTX to evade immune clearance and consequently elongate circulation time.Upon reaching tumor sites,acidity-triggered detachment of PEG results in targeting recovery to enhance tumor cell uptake.Afterward,the VSeM could be dissociated in response to intracellular ROS to trigger VES/MTX release;then the released VES could produce extra ROS to accelerate the collapse of VSeM.Finally,the excessive ROS produced from VES could synergize with the released MTX to efficiently suppress tumor growth via orchestrated oxidation-chemotherapy.Our study provides a novel strategy to engineer cascade-responsive nanodrug for synergistic cancer treatment.

A New Type of Nanogel Carrier based on Mixed Pluronic Loaded with Low-Dose Antitumor Drugs

To design a new type of antitumor nanodrug carrier with good biocompatibility, a drug delivery system with a 2.19% drug-loading rate, measured by high-performance liquid chromatography(HPLC), was prepared by membrane hydration using a mixed polymer: Pluronic■ F-127, which binds folic acid(FA), Pluronic■ F-68 and triptolide(TPL)(FA-F-127/F-68-TPL). As a control, another drug delivery system based on a single polymer(FA-F-127-TPL) with a 1.90% drug-loading rate was prepared by substituting F-68 with F-127. The average particle sizes of FA-F-127/F-68-TPL and FA-F-127-TPL measured by a particle size analyzer were 30.7 nm and 31.6 nm, respectively. Their morphology was observed by atomic force microscopy(AFM). The results showed that FA-F-127-TPL self-assembled into nanomicelles, whereas FA-F-127/F-68-TPL self-assembled into nanogels. An MTT assay showed that a very low concentration of FA-F-127/F-68-TPL or FA-F-127-TPL could significantly inhibit the proliferation of multidrug-resistant(MDR) breast cancer cells(MCF-7/ADR cells) and induce cell death. The effects were significantly different from those of free TPL(P < 0.01). Using the fluorescent probe Nile red(Nr) as the drug model, FA-F-127/F-68-Nr nanogels and FAF-127-Nr nanomicelles were prepared and then incubated with human hepatocarcinoma(HepG2) and MCF-7/ADR cells, and the fluorescence intensity in the cells was measured by a multifunctional microplate reader. The results indicated that both FA-F-127/F-68-Nr and FA-F-127-Nr had sustained release in the cells, but HepG2 and MCF-7/ADR cells exhibited significantly higher endocytosis of FA-F-127/F-68-Nr than that of FA-F-127-Nr(P < 0.01). A nude mice transplanted tumor model was prepared to monitor FA-F-127/F-68-Nr in the tumor tissue and organs by whole-body fluorescent imaging. The results showed that FA-F-127/F-68-Nr targeted tumor tissues. The prepared nanogels had small particle size, were easy to swallow, exhibited slow release property,targeted tumor cells, and could improve the antitumor effects of TPL;hence, they are ideal carriers for low-dose antineoplastic drugs.

Applications and challenges of low temperature plasma in pharmaceutical field

Low temperature plasma(LTP)technology has shown an outstanding application value in the pharmaceutical filed in recent ten years.This paper reviews the research advances in LTP,including its effects on enhancing or inhibiting drug activity,its combined use with drugs to treat cancers,its effects on the improvement of drug delivery system,its use in preparation of new inactivated virus vaccines,its use with mass spectrometry for rapid detection of drug quality,and the anti-tumor and sterilization effects of plasma-activated liquids.The paper also analyzes the challenges of LTP in the pharmaceutical filed,hoping to promote related research.

Tumor-targeting intravenous lipid emulsion of paclitaxel:Characteristics,stability,toxicity,and toxicokinetics

Lipid nanoemulsions are promising nanodrug delivery carriers that can improve the efficacy and safety of paclitaxel(PTX).However,no intravenous lipid emulsion of PTX has been approved for clinical treatment,and systemic safety profiles have not yet been reported.Here we outline the development of a PTXloaded tumor-targeting intravenous lipid emulsion(PTX Emul)and describe its characteristics,colloidal stability,and systemic safety profiles in terms of acute toxicity,long-term toxicity,and toxicokinetics.We also compare PTX Emul with conventional PTX injection.Results showed that PTX Emul exhibited an ideal average particle size(approximately 160 nm)with narrow size distribution and robust colloidal stability under different conditions.Hypersensitivity reaction and hemolysis tests revealed that PTX Emul did not induce hypersensitivity reactions and had no hemolytic potential.In addition,where the alleviated systemic toxicity of PTX Emul may be attributed to the altered toxicokinetic characteristics in beagle dogs,including the decreased AUC and increased plasma clearance and volume of distribution,PTX Emul alleviated acute and long-term toxicity as evidenced by the enhanced the median lethal dose and approximate lethal dose,moderate body weight change,decreased bone marrow suppression and organ toxicity compared with those under PTX injection at the same dose.A fundamental understanding of the systemic safety profiles,high tumor-targeting efficiency,and superior antitumor activity in vivo of PTX Emul can provide powerful evidence of its therapeutic potential as a future treatment for breast cancer.

In Vivo Animal Model Evaluation of a Powerful Oral Nanomedicine for Treating Breast Cancer in BALB/c Mice Using 4T1 Cell Lines without Chemotherapy

Nanopharmaceuticals containing quantum dot nanoparticles (Q-Dot NPs) for treating serious cancers such as breast cancer have made fantastic proposals. In this study, ZnO quantum dot NPs are formulated via ZnO@PVP nanopolymer as co-assistants coordinating with efficacious suitable wetting agents, PEG-binding compound, and W/O emulsifier for producing eco-friendly water-based nanodrug. Several characterization techniques containing SEM, TEM, FTIR, photoluminescence, zeta potential, and UV-Vis absorption were employed for ZnO Q-Dot NPs in nanodrug. This work aims to investigate the anti-tumor effects of such nanomedicine on the 4T1 breast cancer cell line in BALB/c mice, being elaborated through intraperitoneal, injection (IVP) and oral therapy. The impressive findings showed that ZnO nanodrug caused changes in blood factors, having the most effectiveness at 40 μg/ml concentration after two weeks of oral treatments. The significant increase in white blood cells (WBC) neutrophils and meaningful decreases in lymphocytes and especially cholesterol were powerful simultaneous impacts, successfully treating malignant breast cancer masses. In this significant animal model research for breast cancer, the sick mice recovered entirely and even had a safe space to mate. Histopathological results showed no evidence of breast tumor formation or metastasis in the group treated with nanodrug and their children. This nanomedicine has a therapeutic effect, and is ready to be applied for treating volunteer breast cancer patients. However, its prevention (inhibitory) effect can also be analyzed and added to current data in future studies.

A novel marine-derived anti-acute kidney injury agent targeting peroxiredoxin 1 and its nanodelivery strategy based on ADME optimization

Insufficient therapeutic strategies for acute kidney injury(AKI)necessitate precision therapy targeting its pathogenesis.This study reveals the new mechanism of the marine-derived anti-AKI agent,piericidin glycoside S14,targeting peroxiredoxin 1(PRDX1).By binding to Cys83 of PRDX1 and augmenting its peroxidase activity,S14 alleviates kidney injury efficiently in Prdx1-overexpression(Prdx1-OE)mice.Besides,S14 also increases PRDX1 nuclear translocation and directly activates the Nrf2/HO-1/NQO1 pathway to inhibit ROS production.Due to the limited druggability of S14 with low bioavailability(2.6%)and poor renal distribution,a pH-sensitive kidney-targeting dodecanaminechitosan nanoparticle system is constructed to load S14 for precise treatment of AKI.L-Serine conjugation to chitosan imparts specificity to kidney injury molecule-1(Kim-1)-overexpressed cells.The developed S14-nanodrug exhibits higher therapeutic efficiency by improving the in vivo behavior of S14 significantly.By encapsulation with micelles,the AUC_(0-t),half-life time,and renal distribution of S14 increase 2.5-,1.8-,and 3.1-fold,respectively.The main factors contributing to the improved druggability of S14 nanodrugs include the lower metabolic elimination rate and UDPglycosyltransferase(UGT)-mediated biotransformation.In summary,this study identifies a new therapeutic target for the marine-derived anti-AKI agent while enhancing its ADME properties and druggability through nanotechnology,thereby driving advancements in marine drug development for AKI.

Highly efficient tumor-targeted nanomedicine assembled from affibody-drug conjugate for colorectal cancer therapy

Affibody is a new class of small non-immunoglobulin affinity proteins that possesses high affinity at the picomole level to several tumor overexpressed receptors.Owing to the simple framework,affibody is flexible for modification with payload,but the relatively low molecular weight of this construction simultaneously results in short half-life time which hinders its application in cancer therapy.In this work,we prepared a nanomedicine self-assembled from the conjugate of affibody(ZPDGFRβ:09591,PDGFRβ:platelet-derived growth factor receptorβ)with monomethyl auristatin E(MMAE)through cathepsin B cleavable dipeptide linker for targeted colorectal cancer therapy.The nanoscale characteristics of ZPDGFRβ:09591-MMAE affibody-drug conjugate nanomedicine(ZPDGFRβ:09591-M ADCN)resulted in enhanced pharmacokinetics,improved drug accumulation,and promoted biosecurity performance than those of free drugs.As a result,ZPDGFRβ:09591-M ADCN exhibited excellent antitumor efficacy with tumor inhibition rates(TIR)over 99.0%in PDGFRβ-positive tumor models with small solid tumors(~150 mm^(3))or large established tumors(~500 mm^(3)),indicating that ZPDGFRβ:09591-MMAE ADCN is promising for the clinic application in colorectal cancer therapy.

Cooperative coordination-mediated multi-component self-assembly of“all-in-one”nanospike theranostic nano-platform for MRI-guided synergistic therapy against breast cancer

Carrier-free multi-component self-assembled nano-systems have attracted widespread attention owing to their easy preparation,high drug-loading efficiency,and excellent therapeutic efficacy.Herein,MnAs-ICG nanospike was generated by self-assembly of indocyanine green(ICG),manganese ions(Mn^(2+)),and arsenate(AsO_(4)^(3−))based on electrostatic and coordination interactions,effectively integrating the bimodal imaging ability of magnetic resonance imaging(MRI)and fluorescence(FL)imaging-guided synergistic therapy of photothermal/chemo/chemodynamic therapy within an“all-in-one”theranostic nano-platform.The as-prepared MnAs-ICG nanospike had a uniform size,well-defined nanospike morphology,and impressive loading capacities.The MnAs-ICG nanospike exhibited sensitive responsiveness to the acidic tumor microenvironment with morphological transformation and dimensional variability,enabling deep penetration into tumor tissue and on-demand release of functional therapeutic components.In vitro and in vivo results revealed that MnAs-ICG nanospike showed synergistic tumor-killing effect,prolonged blood circulation and increased tumor accumulation compared to their individual components,effectively resulting in synergistic therapy of photothermal/chemo/chemodynamic therapy with excellent anti-tumor effect.Taken together,this new strategy might hold great promise for rationally engineering multifunctional theranostic nano-platforms for breast cancer treatment.

Mitochondria-acting carrier-free nanoplatform self-assembled by a-tocopheryl succinate carrying cisplatin for combinational tumor therapy

Unsatisfactory drug loading capability,potential toxicity of the inert carrier and the limited therapeutic effect of a single chemotherapy drug are all vital inhibitory factors of carrier-assisted drug delivery systems for chemotherapy.To address the above obstacles,a series of carrier-free nanoplatforms self-assembled by dual-drug conjugates was constructed to reinforce chemotherapy against tumors by simultaneously disrupting intratumoral DNA activity and inhibiting mitochondria function.In this nanoplatform,the mitochondria-targeting small-molecular drug,a-tocopheryl succinate(TOS),firstly self-assembled into nanoparticles,which then were used as the carrier to conjugate cisplatin(CDDP).Systematic characterization results showed that this nanoplatform exhibited suitable particle size and a negative surface charge with good stability in physicochemical environments,as well as pH-sensitive drug release and efficient cellular uptake.Due to the combined effects of reactive oxygen species(ROS)generation by TOS and DNA damage by CDDP,the developed nanoplatform could induce mitochondrial dysfunction and elevated cell apoptosis,resulting in highly efficient anti-tumor outcomes in vitro.Collectively,the combined design principles adopted for carrier-free nanodrugs construction in this study aimed at targeting different intracellular organelles for facilitating ROS production and DNA disruption can be extended to other carrier-free nanodrugs-dependent therapeutic systems.

Reconstituted high-density lipoproteins: novel biomimetic nanocarriers for drug delivery

High-density lipoproteins(HDL) are naturally-occurring nanoparticles that are biocompatible,non-immunogenic and completely biodegradable. These endogenous particles can circulate for an extended period of time and transport lipids, proteins and micro RNA from donor cells to recipient cells.Based on their intrinsic targeting properties, HDL are regarded as promising drug delivery systems. In order to produce on a large scale and to avoid blood borne pollution, reconstituted high-density lipoproteins(rHDL) possessing the biological properties of HDL have been developed. This review summarizes the biological properties and biomedical applications of rHDL as drug delivery platforms. It focuses on the emerging approaches that have been developed for the generation of biomimetic nanoparticles rHDL to overcome the biological barriers to drug delivery, aiming to provide an alternative,promising avenue for efficient targeting transport of nanomedicine.

A smart dual-drug nanosystem based on coassembly of plant and food-derived natural products for synergistic HCC immunotherapy

Nanotechnology has emerged as an ideal approach for achieving the efficient chemo agent delivery.However,the potential toxicity and unclear internal metabolism of most nano-carriers was still a major obstacle for the clinical application.Herein,a novel"core-shell"co-assembly carrier-free nanosystem was constructed based on natural sources of ursolic acid(UA)and polyphenol(EGCG)with the EpCAM-aptamer modification for hepatocellular carcinoma(HCC)synergistic treatment.As the nature products derived from food-plant,UA and EGCG had good anticancer activities and low toxicity.With the simple and"green"method,the nanodrugs had the advantages of good stability,p H-responsive and strong penetration of tumor tissues,which was expected to increase tumor cellular uptake,long circulation and effectively avoid the potential defects of traditional carriers.The nanocomplex exhibited the low cytotoxicity in the normal cells in vitro,good biosafety of organic tissues and efficient tumor accumulation in vivo.Importantly,UA combined with EGCG showed the immunotherapy by activating the innate immunity and acquired immunity resulting in significant synergistic therapeutic effect.The research could provide new ideas for the research and development of self-assembly delivery system in the future,and offer effective intervention strategies for clinical HCC treatment.

Engineered protein nanodrug as an emerging therapeutic tool

Functional proteins are the most versatile macromolecules.They can be obtained by extraction from natural sources or by genetic engineering technologies.The outstanding selectivity,specificity,binding activity,and biocompatibility endow engineered proteins with outstanding performance for disease therapy.Nevertheless,their stability is dramatically impaired in blood circulation,hindering clinical translations.Thus,many strategies have been developed to improve the stability,efficacy,bioavailability,and productivity of therapeutic proteins for clinical applications.In this review,we summarize the recent progress in the fabrication and application of therapeutic proteins.We first introduce various strategies for improving therapeutic efficacy via bioengineering and nanoassembly.Furthermore,we highlight their diverse applications as growth factors,nanovaccines,antibody-based drugs,bioimaging molecules,and cytokine receptor antagonists.Finally,a summary and perspective for the future development of therapeutic proteins are presented.

Local T regulatory cells depletion by an integrated nanodrug system for efficient chem-immunotherapy of tumor

T regulatory(Treg) cell is a major immunosuppressive factor that restrains the antitumor effect of immunotherapy, because it gets more after the immune activation and is hardly to be eliminated. Here, an acid-sensitive integrated nanodrug system is designed to activate antitumor immune response as well as locally deplete Treg cells with low side effect. The nanosystem is synthetized by coordinating doxorubicin(DOX) and pentoxifylline(PTX) with Zn ions, then stabilized via liposome encapsulation(denoted as DTX@Lipo). DTX@Lipo can activate antitumor immune effect by chemotherapy of DOX. Besides, the release of PTX inhibits c-Rel expression, leading to the reduction of Treg cells in tumor site. Owing to the good tumor accumulation and local drug release ability, DTX@Lipo exhibits better biosafety and convenience than traditional antibody blockade method for Treg cells depletion. According to the results of in vivo experiments, the nanodrug system can significantly increase the ratio between effector T(Teff) cells and Treg cells locally, resulting in an immunoactivated tumor microenvironment. Importantly, it exhibits significant antitumor effect when combined with PD-1 blockade therapy, providing great potential for tumor therapy.

Engineering a Floxuridine-integrated RNA Prism as Precise Nanomedicine for Drug Delivery

Herein,we report a geometrically well-defined prism assembled by two floxuridine(F)integrated RNA strands as a precise nanomedicine for chemodrug delivery.Owing to the similarity between chemotherapeutic F and uridine(U),all uridines in the component RNA strands are replaced by F during their in vitro transcription syntheses.By specifically designing their sequences,F-containing S-shape tiles with the single-stranded loops are constructed and then further assemble into the RNA prism through T-junction interactions and sticky-end cohesions.The present study demonstrates that the F-integrated RNA prism can serve as an efficient platform for chemodrug delivery and anticancer treatment.We believe that the study would help the future development of RNA-based nanomedicine in various applications.

Precise nano-system-based drug delivery and synergistic therapy against androgen receptor-positive triple-negative breast cancer

Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize with enzalutamide,a second-generation AR inhibitor,in TNBC.By using a strategy for screening drug combinations based on the Sensitivity Index(SI),we found that MK-8776,a selective checkpoint kinase1(CHK1)inhibitor,showed favorable synergism with enzalutamide in AR-positive TNBC.The combination of enzalutamide and MK-8776 was found to exert more significant anti-tumor effects in TNBC than the single application of enzalutamide or MK-8776,respectively.Furthermore,a nanoparticle-based on hyaluronic acid(HA)-modified hollow-manganese dioxide(HMnO_(2)),named HMnE&M@H,was established to encapsulate and deliver enzalutamide and MK-8776.This HA-modified nanosystem managed targeted activation via pH/glutathione responsiveness.HMnE&M@H repressed tumor growth more obviously than the simple addition of enzalutamide and MK-8776 without a carrier.Collectively,our study elucidated the synergy of enzalutamide and MK-8776 in TNBC and developed a novel tumor-targeted nano drug delivery system HMnE&M@H,providing a potential therapeutic approach for the treatment of TNBC.