Trisulfide bond-mediated doxorubicin dimeric prodrug nanoassemblies with high drug loading, high self-assembly stability, and high tumor selectivity

Emerging nanomedicines for macrophage-mediated cancer therapy

Tumor-associated macrophages (TAMs) contribute to tumor progression by promoting angiogenesis, remodeling the tumor extracellular matrix, inducing tumor invasion and metastasis, as well as immune evasion. Due to the high plasticity of TAMs, they can polarize into different phenotypes with distinct functions, which are primarily categorized as the pro-inflammatory, anti-tumor M1 type, and the anti-inflammatory, pro-tumor M2 type. Notably, anti-tumor macrophages not only directly phagocytize tumor cells, but also present tumor-specific antigens and activate adaptive immunity. Therefore, targeted regulation of TAMs to unleash their potential anti-tumor capabilities is crucial for improving the efficacy of cancer immunotherapy. Nanomedicine serves as a promising vehicle and can inherently interact with TAMs, hence, emerging as a new paradigm in cancer immunotherapy. Due to their controllable structures and properties, nanomedicines offer a plethora of advantages over conventional drugs, thus enhancing the balance between efficacy and toxicity. In this review, we provide an overview of the hallmarks of TAMs and discuss nanomedicines for targeting TAMs with a focus on inhibiting recruitment, depleting and reprogramming TAMs, enhancing phagocytosis, engineering macrophages, as well as targeting TAMs for tumor imaging. We also discuss the challenges and clinical potentials of nanomedicines for targeting TAMs, aiming to advance the exploitation of nanomedicine for cancer immunotherapy.

Oxygen-boosted fluorinated prodrug hybrid nanoassemblies for bidirectional amplification of breast cancer ferroptosis

Ferroptosis, a novel form of cell death, has emerged as a promising approach in cancer therapy. However, the single ferroptosis inducer was ineffective, and the induction of ferroptosis was severely limited by hypoxia niches in breast cancer. Herein, we develop a disulfide bond-bridging fluorinated doxorubicin (DOX) prodrug, which can facilitate the formation of hybrid nanoassemblies (NAs) with sorafenib (Sor) through a molecular co-assembly strategy. The incorporation of fluorinated side chains enhances the oxygen-carrying capacity of the NAs, successfully reversing the redox offensive and defensive situation caused by the dilemma of hypoxia. The reactive oxygen species (ROS) generation capacity of DOX via nicotinamide adenine dinucleotide oxidase (NOXs) within hypoxic tumors is significantly enhanced due to the presence of fluorinated oxygen-carrying as a catalytic substrate. Furthermore, the depletion of nicotinamide adenine dinucleotide phosphate (NADPH) significantly impairs the synthesis of glutathione (GSH), which collaboratively inhibits GSH production with Sor. As expected, the NAs with bidirectional amplification of ROS production and GSH inhibition displays potent antitumor activity in 4 T1 breast cancer-bearing mice. Together, this study presents a novel nanotherapeutic approach for ferroptosis-driven tumor therapy.

Revealing the impact of modified modules flexibility on gemcitabine prodrug nanoassemblies for effective cancer therapy

Prodrug nanoassemblies combine the advantages of prodrug strategies and nanotechnology have been widely utilized for delivering antitumor drugs. These prodrugs typically comprise active drug modules, response modules, and modification modules. Among them, the modification modules play a critical factor in improving the self-assembly ability of the parent drug. However, the impact of the specific structure of the modification modules on prodrug self-assembly remains elusive. In this study, two gemcitabine (GEM) prodrugs are developed using 2-octyl-1-dodecanol (OD) as flexible modification modules and cholesterol (CLS) as rigid modification modules. Interestingly, the differences in the chemical structure of modification modules significantly affect the assembly performance, drug release, cytotoxicity, tumor accumulation, and antitumor efficacy of prodrug nanoassemblies. It is noteworthy that the prodrug nanoassemblies constructed with flexible modifying chains (OD) exhibit improved stability, faster drug release, and enhanced antitumor effects. Our findings elucidate the significant impact of modification modules on the construction of prodrug nanoassemblies.

Organelle-Level Trafficking and Metabolism Kinetics for Redox-Responsive Paclitaxel Prodrug Nanoparticles Characterized by Experimental and Modeling Analysis

Redox-responsive self-assembled prodrug nanoparticles have received extensive attention for their high loading efficiency and environmentally responsive properties. However, the intracellular metabolism and transportation kinetics were poorly understood, which limited the rational design and development of this delivery system. Herein, tetraphenylporphyrin-paclitaxel (TxP) prodrugs with thioether, disulfide, and dicarbon linkers (TsP, TssP, and TccP) were synthesized and self-assembled as nanoparticles. The redox responsiveness was investigated both in the simulated medium and in tumor cells via mass spectrometry. TxP NP and PTX concentrations in 4T1 whole cells, endosomal systems, and cytoplasm over time were quantified by UPLC-MS/MS and modeled using the nonlinear mixed effect (NLME) approach. Cytotoxicity was studied in 4T1 and MCF-7 cell lines, and antitumor efficacy was analyzed in 4T1 tumor-bearing mice. Mass spectrometry identified both oxidative and reductive metabolites in redox simulants for TssP NPs and TsP NPs. In 4T1 cells, only reductive metabolites for TssP NPs were detected, while both oxidative and reductive metabolites for TsP NPs were detected. The developed subcellular pharmacokinetic model suggested that the estimated metabolism rates of TxP NPs in endosomal systems were 10 to 27 times of the rates in cytoplasm, indicating that endosomal systems were the dominant place for intracellular metabolism. These rates were numerically higher for TsP NPs than TssP NPs in endosomal systems (1.7-fold) and the cytoplasm (2.5-fold). The internalization of nanoparticles was identified to be slow (kmax,int, 0.015 h-1) and saturable. The transportation rate constant across the endosomal membranes was fast for PTX (27.1 h-1) and slow for TxP NPs (0.098 h-1). TsP and TssP NPs had comparable in vivo antitumor efficacy, which was higher than that of TccP NPs. This study quantified the organelle-level transportation and metabolism kinetics for three prodrug nanoparticles with redox-responsive or inert linkers using a combined experimental and modeling approach. These findings and the modeling framework might inform future studies for redox-responsive prodrug design and drug delivery systems.

Hydroxyl-based acid-hypersensitive acetal ester bond: Design, synthesis and the application potential in nanodrugs

Targeted drug delivery systems exploiting the acidic tumor microenvironment have been thriving, with responsive modifications to the active sites like hydroxyl groups enhancing stability, reducing toxicity, and boosting targeted bioavailability. Yet, the utility of hydroxyl-based acid-sensitive linkages is currently constrained by the intricacy of synthesis, questionable stability, and an inability to discern between physiological pH levels associated with health and disease. Here, we unveiled a novel hydroxyl-based acid-labile linkage, the "acetal ester bond", which not only excelled in its hypersensitive acid responsiveness, but was also facile to synthesize, with exceptionally high yields (>80 %) of final products derived from primary, linear secondary, cyclic secondary, and tertiary alcohols consistently, demonstrating its broad applicability. Further research indicated that the acetal ester bond bearing-paclitaxel conjugate (PTX-COU) with the ability to self-assembly, remained intact in simulated physiological settings, while swiftly hydrolyzed to release PTX in the acidic tumor environment within minutes, contributing to mitigated systemic toxicity and improved bioavailability. In vitro and in vivo experiments demonstrated that PTX-COU outperformed PTX in tumor growth inhibition due to drug accumulation facilitated by acid-responsive target release. This discovery offered a promising solution for pH-triggered drug release, providing new insights and methods for the development of novel targeted drug delivery systems.

Combating tumor PARP inhibitor resistance: Combination treatments, nanotechnology, and other potential strategies

PARP (poly (ADP-ribose) polymerase) inhibitors (PARPi) have demonstrated significant potential in cancer treatment, particularly in tumors with breast cancer susceptibility gene (BRCA) mutations and other DNA repair deficiencies. However, the development of resistance to PARPi has become a major challenge in their clinical application. The emergence of drug resistance leads to reduced efficacy of the PARPi over time, impacting long-term treatment outcomes and survival rates. PARPi resistance in tumors often arises as cells activate alternative DNA repair pathways or evade the effect of PARPi, diminishing therapeutic effectiveness. Consequently, overcoming resistance is crucial for maintaining treatment efficacy and improving patient prognosis. This paper reviews the strategies to overcome PARPi resistance through combination treatment and nanotechnology therapy. We first review the current combination therapies with PARPi, including anti-angiogenic therapies, radiotherapies, immunotherapies, and chemotherapies, and elucidate their mechanisms for overcoming PARPi resistance. Additionally, this paper focuses on the application of nanotechnology in improving the effectiveness of PARPi and overcoming drug resistance. Subsequently, this paper presents several promising strategies to tackle PARPi resistance, including but not limited to: structural modifications of PARPi, deployment of gene editing systems, implementation of "membrane lipid therapy," and modulation of cellular metabolism in tumors. By integrating these strategies, this research will provide comprehensive approaches to overcome the resistance of PARPi in cancer treatment and offer guidance for future research and clinical practice.

A minimalist multifunctional nano-prodrug for drug resistance reverse and integration with PD-L1 mAb for enhanced immunotherapy of hepatocellular carcinoma

Clinical treatment of hepatocellular carcinoma (HCC) with 5-fluorouracil (5-FU), the primary anticancer agent, remains unsatisfactory due to the glutathione (GSH)-associated drug resistance and immunosuppressive microenvironment of HCC. To develop a facile yet robust strategy to overcome 5-FU resistance for enhanced immunotherapy treatment of HCC via all dimensional GSH exhaustion, we report in this study construction of a minimalist prodrug consisting of 5-FU linked to an indoleamine-(2,3)-dioxygenase (IDO) inhibitor (IND) via a disulfide bridge, FU-SS-IND that can further self-assemble into stabilized nanoparticles, FU-SS-IND NPs. Specifically, besides the disulfide linker-induced GSH exhaustion, IND inhibits GSH biosynthesis and enhances the effector function of T cells for turning a "cold" tumor to a "hot" one, which synergistically achieving a tumor inhibition rate (TIR) of 92.5% in a 5-FU resistant mice model. Most importantly, FU-SS-IND NPs could upregulate programmed death ligand 1 (PD-L1) expression on the surface of tumor cells, which enables facile combination with immune checkpoint blockade (ICB) for a ultimate prolonged survival lifetime of 5-FU-resistant tumors-bearing mice. Overall, the minimalist bioreducible nano-prodrug developed herein demonstrates great translatable potential for efficiently reversing drug resistance and enhancing immunotherapy of HCC.

Preparation of Disulfide/Trisulfide Core-Cross-Linked Polycarbonate Nanocarriers for Intracellular Reduction-Triggered Drug Release

Polymeric nanocarriers have attracted significant attention in the field of anticancer drug delivery due to their unique advantages. However, designing nanocarriers that can maintain stability in the bloodstream while achieving specific drug release within tumor cells remains a major challenge. To address this issue, constructing reversible cross-linked polymeric nanocarriers that are sensitive to the intracellular reducible glutathione (GSH) characteristic of the tumor microenvironment is a promising strategy. Based on this, we designed and synthesized two novel six-membered bicyclic carbonate monomers containing disulfide (DSBC) and trisulfide (TSBC) bonds. Through a one-step ring-opening polymerization, a series of reduction-sensitive polycarbonate copolymers (i.e., PEG-PDSBC and PEG-PTSBC) were prepared, and doxorubicin (DOX)-loaded nanoparticles were fabricated using a nanoprecipitation method. The in vitro drug release behaviors of these nanoparticles were systematically investigated. The results showed that these polymers, due to the cross-linked structure formed by the ring-opening polymerization of their bicyclic monomers, could self-assemble into stable nanoparticles. Under different concentrations of glutathione, DOX-loaded PEG-PTSBC nanoparticles demonstrated faster drug release, indicating more optimized intracellular drug release properties. Further cytotoxicity experiments revealed that both types of blank nanoparticles exhibited good biocompatibility with the 4T1 and NIH-3T3 cells. Fluorescence microscopy and flow cytometry results further indicated that DOX-loaded PEG-PTSBC nanoparticles released more drugs in 4T1 cells, significantly inhibiting tumor cell growth compared with DOX-loaded PEG-PDSBC nanoparticles, with no noticeable difference in NIH-3T3 normal cells. In conclusion, this study suggests that trisulfide cross-linked polycarbonate-based nanocarriers hold promise as an anticancer drug delivery system that combines stability in the bloodstream with specific intracellular drug release, offering new insights for the development of novel, efficient, and safe anticancer nanomedicines.

Replenishing Cation-π Interactions for the Fabrication of Mesoporous Levodopa Nanoformulations for Parkinson Remission

Directly assembling drugs into mesoporous nanoformulations will be greatly favored due to the combination of enhanced drug delivery efficiency and mesostructure-enabled nanobio interactions. However, such an approach is hindered due to the lack of understanding of polymer nanoparticles' formation mechanism, especially the relationship between polymerization, self-assembly, and the nucleation process. Here, by investigating the levodopa and dopamine polymerization process, we identify π-cation interaction as pivotal in the self-assembly and nucleation control of dopa molecules. Thus, through manipulation of the π-cation interaction, we present the direct assembly of a commercial drug, levodopa, into mesoporous nanoformulations. The synthesized nanospheres, approximately 200 nm in diameter, exhibit uniform mesopores of around 8 nm. These nanoformulations, abundant in mesopores, enhance chiral phenylalanine interaction with α-synuclein (Syn), curbing aggregation, safeguarding neurons, and alleviating Parkinson's pathology. When combating α-synuclein, the nanoformulation achieved ∼100% inhibition of protein aggregation and sustained neuron viability up to 300%. We believe that this study may advance mesoscale self-assembly knowledge, guiding future nanopharmaceutical developments.

Hybrid Homodimeric Prodrug Nanoassemblies for Low-Toxicity and Synergistic Chemophotodynamic Therapy of Melanoma

Synergistically active nanoparticles hold great promise for facilitating multimodal cancer therapy. However, strategies for their feasible manufacture and optimizing their formulations remain lacking. Herein, we developed hybrid homodimeric prodrug nanotherapeutics with tumor-restricted drug activation and chemophotodynamic pharmacology by leveraging the supramolecular nanoassembly of small molecules. The covalent dimerization of cytotoxic taxane chemotherapy via reactive oxygen species (ROS)-activated linker yielded a homodimeric prodrug, which was further coassembled with a ROS-generating dimeric photosensitizer. The nanoassemblies were readily refined in an amphiphilic PEGylation matrix for particle surface cloaking and in vivo intravenous injection. The nanoassemblies were optimized with favorable stability and combinatorial synergism to kill cancer cells. Upon near-infrared laser irradiation, the neighboring dimer photosensitizer generated ROS, subsequently triggering bond cleavage to facilitate drug activation, which in turn produced synergistic chemophotodynamic effects against cancer. In a preclinical model of melanoma, the intravenous administration of PEGylated nanoassemblies followed by near-infrared tumor irradiation led to significant tumor regression. Furthermore, animals treated with this efficient, photo-activatable nanotherapy exhibited low systemic toxicity even at high doses. This study describes a simple and cost-effective approach to integrate multimodal therapies by creating self-assembling small-molecule prodrugs for designing a combinatorial therapeutic nanosystem. We consider that this new paradigm holds substantial potential for advancing clinical translation.

Self-assembled aldehyde dehydrogenase-activatable nano-prodrug for cancer stem cell-enriched tumor detection and treatment

Cancer stem cells, characterized by high tumorigenicity and drug-resistance, are often responsible for tumor progression and metastasis. Aldehyde dehydrogenases, often overexpressed in cancer stem cells enriched tumors, present a potential target for specific anti-cancer stem cells treatment. In this study, we report a self-assembled nano-prodrug composed of aldehyde dehydrogenases activatable photosensitizer and disulfide-linked all-trans retinoic acid for diagnosis and targeted treatment of cancer stem cells enriched tumors. The disulfide-linked all-trans retinoic acid can load with photosensitizer and self-assemble into a stable nano-prodrug, which can be disassembled into all-trans retinoic acid and photosensitizer in cancer stem cells by high level of glutathione. As for the released photosensitizer, overexpressed aldehyde dehydrogenase catalyzes the oxidation of aldehydes to carboxyl under cancer stem cells enriched microenvironment, activating the generation of reactive oxygen species and fluorescence emission. This generation of reactive oxygen species leads to direct killing of cancer stem cells and is accompanied by a noticeable fluorescence enhancement for real-time monitoring of the cancer stem cells enriched microenvironment. Moreover, the released all-trans retinoic acid, as a differentiation agent, reduce the cancer stem cells stemness and improve the cancer stem cells enriched microenvironment, offering a synergistic effect for enhanced anti-cancer stem cells treatment of photosensitizer in inhibition of in vivo tumor growth and metastasis.

Small molecule-based core and shell cross-linked nanoassemblies: from self-assembly and programmed disassembly to biological applications

Supramolecular assemblies of stimuli-responsive amphiphilic molecules have been of utmost interest in targeted drug delivery applications, owing to their capability of sequestering drug molecules in one set of conditions and releasing them in another. To minimize undesired disassembly and stabilize noncovalently encapsulated drug molecules, the strategy of core or shell cross-linking has become a fascinating approach to constructing cross-linked polymeric or small molecule-based nanoassemblies. In this article, we discuss the design and synthetic strategies for cross-linked nanoassemblies from small molecule-based amphiphiles, with robust stability and enhanced drug encapsulation capability. We highlight their potential biomedical applications, particularly in drug or gene delivery, and cell imaging. This feature article offers a comprehensive overview of the recent developments in the application of small molecule-based covalently cross-linked nanocarriers for materials and biomedical applications, which may inspire the use of these materials as a potential drug delivery system for future chemotherapeutic applications.

Advancements in enzymatic reaction-mediated microbial transformation

Enzymatic reaction-mediated microbial transformation has emerged as a promising technology with significant potential in various industries. These technologies offer the ability to produce enzymes on a large scale, optimize their functionality, and enable sustainable production processes. By utilizing microbial hosts and manipulating their genetic makeup, enzymes can be synthesized efficiently and tailored to meet specific industrial requirements. This leads to enhanced enzyme performance and selectivity, facilitating the development of novel processes and the production of valuable compounds. Moreover, microbial transformation and biosynthesis offer sustainable alternatives to traditional chemical methods, reducing environmental impact and promoting greener production practices. Microbial transformations enrich drug candidate diversity and enhance active ingredient potency, benefiting the pharmaceutical industry. Continued advancements in genetic engineering and bioprocess optimization drive further innovation and application development in Enzymatic reaction-mediated microbial transformation. The integration of AI for predicting enzymatic reactions and optimizing pathways marks a promising direction for future research. In summary, these technologies have the potential to revolutionize several industries by providing cost-effective, sustainable solutions.

Intracellular Redox Environment Determines Cancer-normal Cell Selectivity of Selenium Nanoclusters

Elucidating the chemical structure and intracellular action mechanisms is still the critical limit for the clinical translation of nanomedicines. Intracellular redox environments originating from cell metabolism are key factors affecting internalized drug efficacy. Herein, we engineer Se-Se/Se-S bond to assemble selenium (Se) nanoclusters (SeClus) with intracellular redox environment-driven selective structure. Chemical structure analysis reveals that, the bonding of sulfur atom in intermediates to the two neighboring or interposition Se atoms in Se rings is the key internal driving force for SeClus formation. This nanocluster can be predominantly transformed to selenocysteine to facilitate selenoproteins synthesis in normal cells, while metabolize to cytotoxic SeO3 2- based on the oxidative intracellular redox environment of cancer cells. Resultantly, SeClus exhibit significant cell proliferation inhibition ability to cancer cells and impressive safety to normal cells. Taken together, this study not only clarifies the chemical nature of the atom engineering of SeClus, but also elucidates its intracellular redox environment-oriented anticancer mechanism.

Nanomedicines with Versatile GSH-Responsive Linkers for Cancer Theranostics

Glutathione (GSH)-responsive nanomedicines have generated significant interest in biochemistry, oncology, and material sciences due to their diverse applications, including chemical and biological sensors, diagnostics, and drug delivery systems. The effectiveness of these smart GSH-responsive nanomedicines depends critically on the choice of GSH-responsive linkers. Despite their crucial role, comprehensive reviews of GSH-responsive linkers are scarce, revealing a gap in the current literature. This review addresses this gap by systematically summarizing various GSH-responsive linkers and exploring their potential applications in cancer treatment. We provide an overview of the mechanisms of action of these linkers and their bioapplications, evaluating their advantages and limitations. The insights presented aim to guide the development of advanced GSH-responsive agents for cancer diagnosis and therapy.

Dual-enzyme inhibiting nanomedicines for enhanced cancer chemodynamic therapy by inducing intratumoral acidosis

Deficiency of endogenous hydrogen peroxide and insufficient intracellular acidity are usually two important factors limiting chemodynamic therapy (CDT). Here we report a glutathione-responsive nanomedicine that can provide a suitable environment for CDT by inhibiting dual-enzymes simultaneously. The nanomedicine is constructed by encapsulation of a novel hydrogen sulfide donor in nanomicelle assembled by glutathione-responsive amphiphilic polymer. In response to intracellular glutathione, the nanomedicine can efficiently release the active ingredients hydrogen sulfide, carbonic anhydrase inhibitor and ferrocene. The hydrogen sulfide can increase the concentrations of hydrogen peroxide and lactic acid by inhibiting catalase and enhancing glycolysis. The carbonic anhydrase inhibitor can further induce intratumoral acidosis by inhibiting the function of carbonic anhydrase IX. Therefore, the nanomedicine can provide more efficient reaction conditions for the ferrocene-mediated Fenton reaction to generate abundant toxic hydroxyl radicals. In vivo results show that the combination of enhanced CDT and acidosis can effectively inhibit tumor growth. This design of nanomedicine provides a promising dual-enzyme inhibiting strategy to enhance antitumor efficacy of CDT.

Redox-manipulating nanocarriers for anticancer drug delivery: a systematic review

Spatiotemporally controlled cargo release is a key advantage of nanocarriers in anti-tumor therapy. Various external or internal stimuli-responsive nanomedicines have been reported for their ability to increase drug levels at the diseased site and enhance therapeutic efficacy through a triggered release mechanism. Redox-manipulating nanocarriers, by exploiting the redox imbalances in tumor tissues, can achieve precise drug release, enhancing therapeutic efficacy while minimizing damage to healthy cells. As a typical redox-sensitive bond, the disulfide bond is considered a promising tool for designing tumor-specific, stimulus-responsive drug delivery systems (DDS). The intracellular redox imbalance caused by tumor microenvironment (TME) regulation has emerged as an appealing therapeutic target for cancer treatment. Sustained glutathione (GSH) depletion in the TME by redox-manipulating nanocarriers can exacerbate oxidative stress through the exchange of disulfide-thiol bonds, thereby enhancing the efficacy of ROS-based cancer therapy. Intriguingly, GSH depletion is simultaneously associated with glutathione peroxidase 4 (GPX4) inhibition and dihydrolipoamide S-acetyltransferase (DLAT) oligomerization, triggering mechanisms such as ferroptosis and cuproptosis, which increase the sensitivity of tumor cells. Hence, in this review, we present a comprehensive summary of the advances in disulfide based redox-manipulating nanocarriers for anticancer drug delivery and provide an overview of some representative achievements for combinational therapy and theragnostic. The high concentration of GSH in the TME enables the engineering of redox-responsive nanocarriers for GSH-triggered on-demand drug delivery, which relies on the thiol-disulfide exchange reaction between GSH and disulfide-containing vehicles. Conversely, redox-manipulating nanocarriers can deplete GSH, thereby enhancing the efficacy of ROS-based treatment nanoplatforms. In brief, we summarize the up-to-date developments of the redox-manipulating nanocarriers for cancer therapy based on DDS and provide viewpoints for the establishment of more stringent anti-tumor nanoplatform.

Esterase-Responsive Floxuridine-Tethered Multifunctional Nanoparticles for Targeted Cancer Therapy

Floxuridine is a potential clinical anticancer drug for the treatment of various cancers. However, floxuridine typically causes unfavorable side effects due to its very poor tumor selectivity, and, hence, there is a high demand for the development of novel approaches that permit the targeted delivery of floxuridine into cancerous cells. Herein, the design and synthesis of an esterase-responsive multifunctional nanoformulation for the targeted delivery of floxuridine in esterase-overexpressed cancer cells is reported. Photopolymerization of floxuridine-tethered lipoic acid results in the formation of amphiphilic floxuridine-tethered poly(disulfide). Self-assembly of the amphiphilic polymer results in the formation of nanoparticles with floxuridine decorated on the surfaces of the particles. Integration of aptamer DNA for nucleolin onto the surface of the nanoparticle is demonstrated by exploring the base-pairing interaction of floxuridine with adenine. Targeted internalization of the aptamer-decorated nanoparticle into nucleolin-expressed cancer cells is demonstrated. Esterase triggered cleavage of the ester bond connecting floxuridine with the polymer backbone, and the subsequent targeted delivery of floxuridine into cancer cells is also shown. Excellent therapeutic efficacy is observed both in vitro and also in the 3D tumor spheroid model. This noncovalent strategy provides a simple yet effective strategy for the targeted delivery of floxuridine into cancer cells in a less laborious fashion.

Research Progress on the Mechanism, Monitoring, and Prevention of Cardiac Injury Caused by Antineoplastic Drugs-Anthracyclines

Anthracyclines represent a highly efficacious class of chemotherapeutic agents employed extensively in antitumor therapy. They are universally recognized for their potency in treating diverse malignancies, encompassing breast cancer, gastrointestinal tumors, and lymphomas. Nevertheless, the accumulation of anthracyclines within the body can lead to significant cardiac toxicity, adversely impacting both the survival rates and quality of life for tumor patients. This limitation somewhat restricts their clinical utilization. Determining how to monitor and mitigate their cardiotoxicity at an early stage has become an urgent clinical problem to be solved. Therefore, this paper reviews the mechanism of action, early monitoring, and strategies for the prevention of anthracycline-induced cardiotoxicity for clinical reference.

Cholesterol sulfate-mediated ion-pairing facilitates the self-nanoassembly of hydrophilic cationic mitoxantrone

HYPOTHESIS

Hydrophilic cationic drugs such as mitoxantrone hydrochloride (MTO) pose a significant delivery challenge to the development of nanodrug systems. Herein, we report the use of a hydrophobic ion-pairing strategy to enhance the nano-assembly of MTO.

EXPERIMENTS

We employed biocompatible sodium cholesteryl sulfate (SCS) as a modification module to form stable ion pairs with MTO, which balanced the intermolecular forces and facilitated nano-assembly. PEGylated MTO-SCS nanoassemblies (pMS NAs) were prepared via nanoprecipitation. We systematically evaluated the effect of the ratio of the drug module (MTO) to the modification module (SCS) on the nanoassemblies.

FINDINGS

The increased lipophilicity of MTO-SCS ion pair could significantly improve the encapsulation efficiency (∼97 %) and cellular uptake efficiency of MTO. The pMS NAs showed prolonged blood circulation, maintained the same level of tumor antiproliferative activity, and exhibited reduced toxicity compared with the free MTO solution. It is noteworthy that the stability, cellular uptake, cytotoxicity, and in vivo pharmacokinetic behavior of the pMS NAs increased in proportion to the molar ratio of SCS to MTO. This study presents a self-assembly strategy mediated by ion pairing to overcome the challenges commonly associated with the poor assembly ability of hydrophilic cationic drugs.

Carrier-free nano-prodrugs for minimally invasive cancer therapy

An anticancer nanodrug with few side effects that does not require the use of a nanocarrier, polyethylene glycol, or other additives has been developed. We have fabricated nano-prodrugs (NPDs) composed only of homodimeric prodrugs of the anticancer agent SN-38, which contains a disulfide bond. The prodrugs are stable against hydrolysis but selectively release SN-38 when the disulfide bond is cleaved by glutathione, which is present in high concentrations in cancer cells. The best-performing NPDs showed good dispersion stability in nanoparticle form, and animal experiments revealed that they possess much higher antitumor activity than irinotecan, a clinically applied prodrug of SN-38. This performance was achieved by improving tumor accumulation due to the size effect and targeted drug release mechanism. The present study provides an insight into the development of non-invasive NPDs with high pharmacological activity, and also offers new possibilities for designing prodrug molecules that can release drugs in response to various kinds of triggers.

Carbon-Spaced Tandem-Disulfide Bond Bridge Design Addresses Limitations of Homodimer Prodrug Nanoassemblies: Enhancing Both Stability and Activatability

Redox-responsive homodimer prodrug nanoassemblies (RHPNs) have emerged as a significant technology for overcoming chemotherapeutical limitations due to their high drug-loading capacity, low excipient-associated toxicity, and straightforward preparation method. Previous studies indicated that α-position disulfide bond bridged RHPNs exhibited rapid drug release rates but unsatisfactory assembly stability. In contrast, γ-disulfide bond bridged RHPNs showed better assembly stability but low drug release rates. Therefore, designing chemical linkages that ensure both stable assembly and rapid drug release remains challenging. To address this paradox of stable assembly and rapid drug release in RHPNs, we developed carbon-spaced double-disulfide bond (CSDD)-bridged RHPNs (CSDD-RHPNs) with two carbon-spaces. Pilot studies showed that CSDD-RHPNs with two carbon-spaces exhibited enhanced assembly stability, reduction-responsive drug release, and improved selective toxicity compared to α-/γ-position single disulfide bond bridged RHPNs. Based on these findings, CSDD-RHPNs with four and six carbon-spaces were designed to further investigate the properties of CSDD-RHPNs. These CSDD-RHPNs exhibited excellent assembly ability, safety, and prolonged circulation. Particularly, CSDD-RHPNs with two carbon-spaces displayed the best antitumor efficacy on 4T1 and B16-F10 tumor-bearing mice. CSDD chemical linkages offer novel perspectives on the rational design of RHPNs, potentially overcoming the design limitations regarding contradictory assembly ability and drug release rate.

Stimulus-Responsive Nano-Prodrug Strategies for Cancer Therapy: A Focus on Camptothecin Delivery

Camptothecin (CPT) is a highly cytotoxic molecule with excellent antitumor activity against various cancers. However, its clinical application is severely limited by poor water solubility, easy inactivation, and severe toxicity. Structural modifications and nanoformulations represent two crucial avenues for camptothecin's development. However, the potential for further structural modifications is limited, and camptothecin nanoparticles fabricated via physical loading have the drawbacks of low drug loading and leakage. Prodrug-based CPT nanoformulations have shown unique advantages, including increased drug loading, reduced burst release, improved bioavailability, and minimal toxic side effects. Stimulus-responsive CPT nano-prodrugs that respond to various endogenous or exogenous stimuli by introducing various activatable linkers to achieve spatiotemporally responsive drug release at the tumor site. This review comprehensively summarizes the latest research advances in stimulus-responsive CPT nano-prodrugs, including preparation strategies, responsive release mechanisms, and their applications in cancer therapy. Special focus is placed on the release mechanisms and characteristics of various stimulus-responsive CPT nano-prodrugs and their application in cancer treatment. Furthermore, clinical applications of CPT prodrugs are discussed. Finally, challenges and future research directions for CPT nano-prodrugs are discussed. This review to be valuable to readers engaged in prodrug research is expected.

Regulating Drug Release Performance of Acid-Triggered Dimeric Prodrug-Based Drug Self-Delivery System by Altering Its Aggregation Structure

Dimeric prodrugs have been investigated intensely as carrier-free drug self-delivery systems (DSDSs) in recent decades, and their stimuli-responsive drug release has usually been controlled by the conjugations between the drug molecules, including the stimuli (pH or redox) and responsive sensitivity. Here, an acid-triggered dimeric prodrug of doxorubicin (DOX) was synthesized by conjugating two DOX molecules with an acid-labile ketal linker. It possessed high drug content near the pure drug, while the premature drug leakage in blood circulation was efficiently suppressed. Furthermore, its aggregation structures were controlled by fabricating nanomedicines via different approaches, such as fast precipitation and slow self-assembly, to regulate the drug release performance. Such findings are expected to enable better anti-tumor efficacy with the desired drug release rate, beyond the molecular structure of the dimeric prodrug.

A homologous membrane-camouflaged self-assembled nanodrug for synergistic antitumor therapy

Limited success has been achieved in ferroptosis-induced cancer treatment due to the challenges related to low production of toxic reactive oxygen species (ROS) and inherent ROS resistance in cancer cells. To address this issue, a self-assembled nanodrug have been investigated that enhances ferroptosis therapy by increasing ROS production and reducing ROS inhibition. The nanodrug is constructed by allowing doxorubicin (DOX) to interact with Fe2+ through coordination interactions, forming a stable DOX-Fe2+ chelate, and this chelate further interacts with sorafenib (SRF), resulting in a stable and uniform nanoparticle. In tumor cells, overexpressed glutathione (GSH) triggers the disassembly of nanodrug, thereby activating the drug release. Interestingly, the released DOX not only activates nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) to produce abundant H2O2 production for enhanced ROS production, but also acts as a chemotherapeutics agent, synergizing with ferroptosis. To enhance tumor selectivity and improve the blood clearance, the nanodrug is coated with a related cancer cell membrane, which enhances the selective inhibition of tumor growth and metastasis in a B16F10 mice model. Our findings provide valuable insights into the rational design of self-assembled nanodrug for enhanced ferroptosis therapy in cancer treatment. STATEMENT OF SIGNIFICANCE: Ferroptosis is a non-apoptotic form of cell death induced by the iron-regulated lipid peroxides (LPOs), offering a promising potential for effective and safe anti-cancer treatment. However, two significant challenges hinder its clinical application: 1) The easily oxidized nature of Fe2+ and the low concentration of H2O2 leads to a low efficiency of intracellular Fenton reaction, resulting in poor therapeutic efficacy; 2) The instinctive ROS resistance of cancer cells induce drug resistance. Therefore, we developed a simple and high-efficiency nanodrug composed of self-assembling by Fe2+ sources, H2O2 inducer and ROS resistance inhibitors. This nanodrug can effectively deliver the Fe2+ sources into tumor tissue, enhance intracellular concentration of H2O2, and reduce ROS resistance, achieving a high-efficiency, precise and safe ferroptosis therapy.

Biotin-functionalized nanoparticles: an overview of recent trends in cancer detection

Electrochemical bio-sensing is a potent and efficient method for converting various biological recognition events into voltage, current, and impedance electrical signals. Biochemical sensors are now a common part of medical applications, such as detecting blood glucose levels, detecting food pathogens, and detecting specific cancers. As an exciting feature, bio-affinity couples, such as proteins with aptamers, ligands, paired nucleotides, and antibodies with antigens, are commonly used as bio-sensitive elements in electrochemical biosensors. Biotin-avidin interactions have been utilized for various purposes in recent years, such as targeting drugs, diagnosing clinically, labeling immunologically, biotechnology, biomedical engineering, and separating or purifying biomolecular compounds. The interaction between biotin and avidin is widely regarded as one of the most robust and reliable noncovalent interactions due to its high bi-affinity and ability to remain selective and accurate under various reaction conditions and bio-molecular attachments. More recently, there have been numerous attempts to develop electrochemical sensors to sense circulating cancer cells and the measurement of intracellular levels of protein thiols, formaldehyde, vitamin-targeted polymers, huwentoxin-I, anti-human antibodies, and a variety of tumor markers (including alpha-fetoprotein, epidermal growth factor receptor, prostate-specific Ag, carcinoembryonic Ag, cancer antigen 125, cancer antigen 15-3, etc.). Still, the non-specific binding of biotin to endogenous biotin-binding proteins present in biological samples can result in false-positive signals and hinder the accurate detection of cancer biomarkers. This review summarizes various categories of biotin-functional nanoparticles designed to detect such biomarkers and highlights some challenges in using them as diagnostic tools.

Natural Products for Preventing and Managing Anthracycline-Induced Cardiotoxicity: A Comprehensive Review

Doxorubicin (DOX) is an anthracycline anticancer agent that is highly effective in the treatment of solid tumors. Given the multiplicity of mechanisms involved in doxorubicin-induced cardiotoxicity, it is difficult to identify a precise molecular target for toxicity. The findings of a literature review suggest that natural products may offer cardioprotective benefits against doxorubicin-induced cardiotoxicity, both in vitro and in vivo. However, further confirmatory studies are required to substantiate this claim. It is of the utmost importance to direct greater attention towards the intricate signaling networks that are of paramount importance for the survival and dysfunction of cardiomyocytes. Notwithstanding encouraging progress made in preclinical studies of natural products for the prevention of DOX-induced cardiotoxicity, these have not yet been translated for clinical use. One of the most significant obstacles hindering the development of cardioprotective adjuvants based on natural products is the lack of adequate bioavailability in humans. This review presents an overview of current knowledge on doxorubicin DOX-induced cardiotoxicity, with a focus on the potential benefits of natural compounds and herbal preparations in preventing this adverse effect. As literature search engines, the browsers in the Scopus, PubMed, Web of Science databases and the ClinicalTrials.gov register were used.

Dual-targeted nanoparticulate drug delivery systems for enhancing triple-negative breast cancer treatment

The efficacy of DNA-damaging agents, such as the topoisomerase I inhibitor SN38, is often compromised by the robust DNA repair mechanisms in tumor cells, notably homologous recombination (HR) repair. Addressing this challenge, we introduce a novel nano-strategy utilizing binary tumor-killing mechanisms to enhance the therapeutic impact of DNA damage and mitochondrial dysfunction in cancer treatment. Our approach employs a synergistic drug pair comprising SN38 and the BET inhibitor JQ-1. We synthesized two prodrugs by conjugating linoleic acid (LA) to SN38 and JQ-1 via a cinnamaldehyde thioacetal (CT) bond, facilitating co-delivery. These prodrugs co-assemble into a nanostructure, referred to as SJNP, in an optimal synergistic ratio. SJNP was validated for its efficacy at both the cellular and tissue levels, where it primarily disrupts the transcription factor protein BRD4. This disruption leads to downregulation of BRCA1 and RAD51, impairing the HR process and exacerbating DNA damage. Additionally, SJNP releases cinnamaldehyde (CA) upon CT linkage cleavage, elevating intracellular ROS levels in a self-amplifying manner and inducing ROS-mediated mitochondrial dysfunction. Our results indicate that SJNP effectively targets murine triple-negative breast cancer (TNBC) with minimal adverse toxicity, showcasing its potential as a formidable opponent in the fight against cancer.

Protein-nanoparticle co-assembly supraparticles for drug delivery: Ultrahigh drug loading and colloidal stability, and instant and complete lysosomal drug release

Two frequent problems hindering clinical translation of nanomedicine are low drug loading and low colloidal stability. Previous efforts to achieve ultrahigh drug loading (>30 %) introduce new hurdles, including lower colloidal stability and others, for clinical translation. Herein, we report a new class of drug nano-carriers based on our recent finding in protein-nanoparticle co-assembly supraparticle (PNCAS), with both ultrahigh drug loading (58 % for doxorubicin, i.e., DOX) and ultrahigh colloidal stability (no significant change in hydrodynamic size after one year). We further show that our PNCAS-based drug nano-carrier possesses a built-in environment-responsive drug release feature: once in lysosomes, the loaded drug molecules are released instantly (<1 min) and completely (∼100 %). Our PNCAS-based drug delivery system is spontaneously formed by simple mixing of hydrophobic nanoparticles, albumin and drugs. Several issues related to industrial production are studied. The ultrahigh drug loading and stability of DOX-loaded PNCAS enabled the delivery of an exceptionally high dose of DOX into a mouse model of breast cancer, yielding high efficacy and no observed toxicity. With further developments, our PNCAS-based delivery systems could serve as a platform technology to meet the multiple requirements of clinical translation of nanomedicines.

Amino acid-based metallo-supramolecular nanoassemblies capable of regulating cellular redox homeostasis for tumoricidal chemo-/photo-/catalytic combination therapy

Nanozymes, as nanomaterials with natural enzyme activities, have been widely applied to deliver various therapeutic agents to synergistically combat the progression of malignant tumors. However, currently common inorganic nanozyme-based drug delivery systems still face challenges such as suboptimal biosafety, inadequate stability, and inferior tumor selectivity. Herein, a super-stable amino acid-based metallo-supramolecular nanoassembly (FPIC NPs) with peroxidase (POD)- and glutathione oxidase (GSHOx)-like activities was fabricated via Pt4+-driven coordination co-assembly of l-cysteine derivatives, the chemotherapeutic drug curcumin (Cur), and the photosensitizer indocyanine green (ICG). The superior POD- and GSHOx-like activities could not only catalyze the decomposition of endogenous hydrogen peroxide into massive hydroxyl radicals, but also deplete the overproduced glutathione (GSH) in cancer cells to weaken intracellular antioxidant defenses. Meanwhile, FPIC NPs would undergo degradation in response to GSH to specifically release Cur, causing efficient mitochondrial damage. In addition, FPIC NPs intrinsically enable fluorescence/photoacoustic imaging to visualize tumor accumulation of encapsulated ICG in real time, thereby determining an appropriate treatment time point for tumoricidal photothermal (PTT)/photodynamic therapy (PDT). In vitro and in vivo findings demonstrated the quadruple orchestration of catalytic therapy, chemotherapeutics, PTT, and PDT offers conspicuous antineoplastic effects with minimal side reactions. This work may provide novel ideas for designing supramolecular nanoassemblies with multiple enzymatic activities and therapeutic functions, allowing for wider applications of nanozymes and nanoassemblies in biomedicine.

Enhancing cancer therapy: The role of drug delivery systems in STAT3 inhibitor efficacy and safety

The signal transducer and activator of transcription 3 (STAT3), a member of the STAT family, resides in the nucleus to regulate genes essential for vital cellular functions, including survival, proliferation, self-renewal, angiogenesis, and immune response. However, continuous STAT3 activation in tumor cells promotes their initiation, progression, and metastasis, rendering STAT3 pathway inhibitors a promising avenue for cancer therapy. Nonetheless, these inhibitors frequently encounter challenges such as cytotoxicity and suboptimal biocompatibility in clinical trials. A viable strategy to mitigate these issues involves delivering STAT3 inhibitors via drug delivery systems (DDSs). This review delineates the regulatory mechanisms of the STAT3 signaling pathway and its association with cancer. It offers a comprehensive overview of the current application of DDSs for anti-STAT3 inhibitors and investigates the role of DDSs in cancer treatment. The conclusion posits that DDSs for anti-STAT3 inhibitors exhibit enhanced efficacy and reduced adverse effects in tumor therapy compared to anti-STAT3 inhibitors alone. This paper aims to provide an outline of the ongoing research and future prospects of DDSs for STAT3 inhibitors. Additionally, it presents our insights on the merits and future outlook of DDSs in cancer treatment.

Accelerating diabetic wound healing by ROS-scavenging lipid nanoparticle-mRNA formulation

Current treatment options for diabetic wounds face challenges due to low efficacy, as well as potential side effects and the necessity for repetitive treatments. To address these issues, we report a formulation utilizing trisulfide-derived lipid nanoparticle (TS LNP)-mRNA therapy to accelerate diabetic wound healing by repairing and reprogramming the microenvironment of the wounds. A library of reactive oxygen species (ROS)-responsive TS LNPs was designed and developed to encapsulate interleukin-4 (IL4) mRNA. TS2-IL4 LNP-mRNA effectively scavenges excess ROS at the wound site and induces the expression of IL4 in macrophages, promoting the polarization from the proinflammatory M1 to the anti-inflammatory M2 phenotype at the wound site. In a diabetic wound model of db/db mice, treatment with this formulation significantly accelerates wound healing by enhancing the formation of an intact epidermis, angiogenesis, and myofibroblasts. Overall, this TS LNP-mRNA platform not only provides a safe, effective, and convenient therapeutic strategy for diabetic wound healing but also holds great potential for clinical translation in both acute and chronic wound care.

A convenient protonated strategy for constructing nanodrugs from hydrophobic drug-inhibitor conjugates to reverse tumor multidrug resistance

Combination therapy has proven effective in counteracting tumor multidrug resistance (MDR). However, the pharmacokinetic differences among various drugs and inherent water insolubility for most small molecule agents greatly hinder their synergistic effects, which makes the delivery of drugs for combination therapy in vivo a key problem. Herein, we propose a protonated strategy to transform a water-insoluble small molecule drug-inhibitor conjugate into an amphiphilic one, which then self-assembles into nanoparticles for co-delivery in vivo to overcome tumor MDR. Specifically, paclitaxel (PTX) is first coupled with a third-generation P-glycoprotein (P-gp) inhibitor zosuquidar (Zos) through a glutathione (GSH)-responsive disulfide bond to produce a hydrophobic drug-inhibitor conjugate (PTX-ss-Zos). Subsequently treated with hydrochloric acid ethanol solution (HCl/EtOH), PTX-ss-Zos is transformed into the amphiphilic protonated precursor and then forms nanoparticles (PTX-ss-Zos@HCl NPs) in water by molecular self-assembly. PTX-ss-Zos@HCl NPs can be administered intravenously and accumulated specifically at tumor sites. Once internalized by cancer cells, PTX-ss-Zos@HCl NPs can be degraded under the overexpressed GSH to release PTX and Zos simultaneously, which synergistically reverse tumor MDR and inhibit tumor growth. This offers a promising strategy to develop small molecule self-assembled nanoagents to reverse tumor MDR in combination therapy.

Advances in self-assembled nanotechnology in tumor therapy

The emergence of nanotechnology has opened up a new way for tumor therapy. Among them, self-assembled nanotechnology has received extensive attention in medicine due to its simple preparation process, high drug-loading capacity, low toxicity, and low cost. This review mainly summarizes the preparation methods of self-assembled nano-delivery systems, as well as the self-assembled mechanism of carrier-free nanomedicine, polymer-carried nanomedicine, polypeptide, and metal drugs, and their applications in tumor therapy. In addition, we discuss the advantages and disadvantages, future challenges, and opportunities of these self-assembled nanomedicines, which provide important references for the development and application of self-assembled nanotechnology in the field of medical therapy.

A Trisulfide Bond Containing Biodegradable Polymer Delivering Pt(IV) Prodrugs to Deplete Glutathione and Donate H2S to Boost Chemotherapy and Antitumor Immunity

The clinical application of cisplatin (CisPt) is limited by its dose-dependent toxicity. To overcome this, we developed reduction-responsive nanoparticles (NP(3S)s) for the targeted delivery of a platinum(IV) (Pt(IV)) prodrug to improve efficacy and reduce the toxicity. NP(3S)s could release Pt(II) and hydrogen sulfide (H2S) upon encountering intracellular glutathione, leading to potent anticancer effects. Notably, NP(3S)s induced DNA damage and activated the STING pathway, which is a known promoter for T cell activation. Comparative RNA profiling revealed that NP(3S)s outperformed CisPt in enhancing T cell immunity, antitumor immunity, and oxidative stress pathways. In vivo experiments showed that NP(3S)s accumulated in tumors, promoting CD8+ T cell infiltration and boosting antitumor immunity. Furthermore, NP(3S)s exhibited robust in vivo anticancer efficacy while minimizing the CisPt-induced liver toxicity. Overall, the results indicate NP(3S)s hold great promise for clinical translation due to their low toxicity profile and potent anticancer activity.

Mitochondria-Targeted Prodrug Nanoassemblies for Efficient Ferroptosis-Based Therapy via Devastating Ferroptosis Defense Systems

Ferroptosis is a form of regulated cell death accompanied by lipid reactive oxygen species (ROS) accumulation in an iron-dependent manner. However, the efficiency of tumorous ferroptosis was seriously restricted by intracellular ferroptosis defense systems, the glutathione peroxidase 4 (GPX4) system, and the ubiquinol (CoQH2) system. Inspired by the crucial role of mitochondria in the ferroptosis process, we reported a prodrug nanoassembly capable of unleashing potent mitochondrial lipid peroxidation and ferroptotic cell death. Dihydroorotate dehydrogenase (DHODH) inhibitor (QA) was combined with triphenylphosphonium moiety through a disulfide-containing linker to engineer well-defined nanoassemblies (QSSP) within a single-molecular framework. After being trapped in cancer cells, the acidic condition provoked the structural disassembly of QSSP to liberate free prodrug molecules. The mitochondrial membrane-potential-driven accumulation of the lipophilic cation prodrug was delivered explicitly into the mitochondria. Afterward, the thiol-disulfide exchange would occur accompanied by downregulation of reduced glutathione levels, thus resulting in mitochondria-localized GPX4 inactivation for ferroptosis. Simultaneously, the released QA from the hydrolysis reaction of the adjacent ester bond could further devastate mitochondrial defense and evoke robust ferroptosis via the DHODH-CoQH2 system. This subcellular targeted nanoassembly provides a reference for designing ferroptosis-based strategy for efficient cancer therapy through interfering antiferroptosis systems.

Tetrasulfide bond boosts the anti-tumor efficacy of dimeric prodrug nanoassemblies

Dimeric prodrug nanoassemblies (DPNAs) stand out as promising strategies for improving the efficiency and safety of chemotherapeutic drugs. The success of trisulfide bonds (-SSS-) in DPNAs makes polysulfide bonds a worthwhile focus. Here, we explore the comprehensive role of tetrasulfide bonds (-SSSS-) in constructing superior DPNAs. Compared to trisulfide and disulfide bonds, tetrasulfide bonds endow DPNAs with superlative self-assembly stability, prolonged blood circulation, and high tumor accumulation. Notably, the ultra-high reduction responsivity of tetrasulfide bonds make DPNAs a highly selective "tumor bomb" that can be ignited by endogenous reducing agents in tumor cells. Furthermore, we present an "add fuel to the flames" strategy to intensify the reductive stress at tumor sites by replenishing exogenous reducing agents, making considerable progress in selective tumor inhibition. This work elucidates the crucial role of tetrasulfide bonds in establishing intelligent DPNAs, alongside the combination methodology, propelling DPNAs to new heights in potent cancer therapy.

Current developments and future perspectives of nanotechnology in orthopedic implants: an updated review

Orthopedic implants are the most commonly used fracture fixation devices for facilitating the growth and development of incipient bone and treating bone diseases and defects. However, most orthopedic implants suffer from various drawbacks and complications, including bacterial adhesion, poor cell proliferation, and limited resistance to corrosion. One of the major drawbacks of currently available orthopedic implants is their inadequate osseointegration at the tissue-implant interface. This leads to loosening as a result of immunological rejection, wear debris formation, low mechanical fixation, and implant-related infections. Nanotechnology holds the promise to offer a wide range of innovative technologies for use in translational orthopedic research. Nanomaterials have great potential for use in orthopedic applications due to their exceptional tribological qualities, high resistance to wear and tear, ability to maintain drug release, capacity for osseointegration, and capability to regenerate tissue. Furthermore, nanostructured materials possess the ability to mimic the features and hierarchical structure of native bones. They facilitate cell proliferation, decrease the rate of infection, and prevent biofilm formation, among other diverse functions. The emergence of nanostructured polymers, metals, ceramics, and carbon materials has enabled novel approaches in orthopaedic research. This review provides a concise overview of nanotechnology-based biomaterials utilized in orthopedics, encompassing metallic and nonmetallic nanomaterials. A further overview is provided regarding the biomedical applications of nanotechnology-based biomaterials, including their application in orthopedics for drug delivery systems and bone tissue engineering to facilitate scaffold preparation, surface modification of implantable materials to improve their osteointegration properties, and treatment of musculoskeletal infections. Hence, this review article offers a contemporary overview of the current applications of nanotechnology in orthopedic implants and bone tissue engineering, as well as its prospective future applications.

The effect of lengths of branched-chain fatty alcohols on the efficacy and safety of docetaxel-prodrug nanoassemblies

The self-assembly prodrugs are usually consisted of drug modules, activation modules, and assembly modules. Keeping the balance between efficacy and safety by selecting suitable modules remains a challenge for developing prodrug nanoassemblies. This study designed four docetaxel (DTX) prodrugs using disulfide bonds as activation modules and different lengths of branched-chain fatty alcohols as assembly modules (C16, C18, C20, and C24). The lengths of the assembly modules determined the self-assembly ability of prodrugs and affected the activation modules' sensitivity. The extension of the carbon chains improved the prodrugs' self-assembly ability and pharmacokinetic behavior while reducing the cytotoxicity and increased cumulative toxicity. The use of C20 can balance efficacy and safety. These results provide a great reference for the rational design of prodrug nanoassemblies.

Redox-Responsive Polymeric Nanoparticle for Nucleic Acid Delivery and Cancer Therapy: Progress, Opportunities, and Challenges

Cancer development and progression of cancer are closely associated with the activation of oncogenes and loss of tumor suppressor genes. Nucleic acid drugs (e.g., siRNA, mRNA, and DNA) are widely used for cancer therapy due to their specific ability to regulate the expression of any cancer-associated genes. However, nucleic acid drugs are negatively charged biomacromolecules that are susceptible to serum nucleases and cannot cross cell membrane. Therefore, specific delivery tools are required to facilitate the intracellular delivery of nucleic acid drugs. In the past few decades, a variety of nanoparticles (NPs) are designed and developed for nucleic acid delivery and cancer therapy. In particular, the polymeric NPs in response to the abnormal redox status in cancer cells have garnered much more attention as their potential in redox-triggered nanostructure dissociation and rapid intracellular release of nucleic acid drugs. In this review, the important genes or signaling pathways regulating the abnormal redox status in cancer cells are briefly introduced and the recent development of redox-responsive NPs for nucleic acid delivery and cancer therapy is systemically summarized. The future development of NPs-mediated nucleic acid delivery and their challenges in clinical translation are also discussed.

Synergistic anti-tumor effect of dual drug co-assembled nanoparticles based on ursolic acid and sorafenib

Both ursolic acid (UA) and sorafenib (Sora) have been generally utilized in cancer treatment, and the combination of the two has also shown a good anti-tumor effect. However, single-agent therapy for Hepatocellular carcinoma (HCC) has the disadvantages of multi-drug resistance, poor water solubility and low bioavailability, and the application of traditional nanocarrier materials is limited due to their low drug loading and low carrier-related toxicity. Therefore, we prepared US NPs with different proportions of UA and Sora by solvent exchange method for achieving synergistic HCC therapy. US NPs had suitable particle size, good dispersibility and storage stability, which synergistically inhibited the proliferation of HepG2 cells, SMMC7721 cells and H22 cells. In addition, we also proved that US NPs were able to suppress the migration of HepG2 cells and SMMC7721 cells and reduce the adhesion ability and colony formation ability of these cells. According to the results, US NPs could degrade the membrane potential of mitochondrial, participate in cell apoptosis, and synergistically induce autophagy. Collectively, the carrier-free US NPs provide new strategies for HCC treatment and new ideas for the development of novel nano-drug delivery systems containing UA and Sora.

Chitosan/alginate nanogel potentiate berberine uptake and enhance oxidative stress mediated apoptotic cell death in HepG2 cells

Biopolymer-based nanoscale drug delivery systems have become a promising approach to overcome the limitations associated with conventional chemotherapeutics used for cancer treatment. Herein, we reported to develop a hydrophilic nanogel (NG) composed of Chitosan (Chi) and sodium alginate (Alg) using the ion gelation method for delivering Berberine hydrochloride (BBR), an alkaloid obtained from Berberis aristata roots. The use of different nanocarriers for BBR delivery has been reported previously, but the bioavailability of these carriers was limited due to phagocytic uptake and poor systemic delivery. The developed NG showed enhanced stability and efficient entrapment of BBR ∼92 %, resulting in a significant increase in bioavailability. The pH-dependent release behavior demonstrated sustained and effective release of ∼86 %, ∼74 % and, ∼53 % BBR at pH 5.5, 6.6, and 7.4 respectively after 72h, indicating its potential as a drug carrier. Additionally, the cellular uptake of BBR was significantly higher ∼19 % in the BBR-NG (25 μM) than in bulk BBR (100 μM), leading to enhanced ROS generation, mitochondrial depolarisation, and inhibition of cell proliferation and colony formation in HepG2 cells. In summary, the results suggest that the Chi/Alg biopolymer-based nano-formulation could be an effective approach for delivering BBR and enhancing its cellular uptake, efficacy, and cytotoxicity.

Satellite-Type Sulfur Atom Distribution in Trithiocarbonate Bond-Bridged Dimeric Prodrug Nanoassemblies: Achieving Both Stability and Activatability

Homodimeric prodrug nanoassemblies (HDPNs) hold promise for improving the delivery efficiency of chemo-drugs. However, the key challenge lies in designing rational chemical linkers that can simultaneously ensure the chemical stability, self-assembly stability, and site-specific activation of prodrugs. The "in series" increase in sulfur atoms, such as trisulfide bond, can improve the assembly stability of HDPNs to a certain extent, but limits the chemical stability of prodrugs. Herein, trithiocarbonate bond (─SC(S)S─), with a stable "satellite-type" distribution of sulfur atoms, is developed via the insertion of a central carbon atom in trisulfide bonds. ─SC(S)S─ bond effectively addresses the existing predicament of HDPNs by improving the chemical and self-assembly stability of homodimeric prodrugs while maintaining the on-demand bioactivation. Furthermore, ─SC(S)S─ bond inhibits antioxidant defense system, leading to up-regulation of the cellular ROS and apoptosis of tumor cells. These improvements of ─SC(S)S─ bond endow the HDPNs with in vivo longevity and tumor specificity, ultimately enhancing the therapeutic outcomes. ─SC(S)S─ bond is, therefore, promising for overcoming the bottleneck of HDPNs for efficient oncological therapy.

Multifunctional nano MOF drug delivery platform in combination therapy

Recent preclinical and clinical studies have demonstrated that for cancer treatment, combination therapies are more effective than monotherapies in reducing drug-related toxicity, decreasing drug resistance, and improving therapeutic efficacy. With the rapid development of nanotechnology, the combination of metal-organic frameworks (MOFs) and multi-mode therapy offers a realistic possibility to further improve the shortcomings of cancer treatment. This article focuses on the latest developments, achievements, and treatment strategies of representative multifunctional MOF combination therapies for cancer treatment in recent years, which include not only bimodal combination therapies, but also multi-modal synergistic therapies, further demonstrating the effectiveness and superiority of the MOF drug delivery systems in cancer treatment.

The spatiotemporal journey of nanomedicines in solid tumors on their therapeutic efficacy

The rapid development of nanomedicines is revolutionizing the landscape of cancer treatment, while effectively delivering them into solid tumors remains a formidable challenge. Currently, there is a huge disconnect on therapeutic response between regulatory approved nanomedicines and laboratory reported nanoparticles. The discrepancy is mainly resulted from the failure of using the classic overall pharmacokinetics behaviors of nanomedicines in tumors to predict the antitumor efficacy. Increasing evidence has revealed that the therapeutic efficacy predominantly relies on the intratumoral spatiotemporal distribution of nanomedicines. This review focuses on the spatiotemporal distribution of systemically administered chemotherapeutic nanomedicines in solid tumor. Firstly, the intratumoral biological barriers that regulate the spatiotemporal distribution of nanomedicines are described in detail. Next, the influences on antitumor efficacy caused by the spatial distribution and temporal drug release of nanomedicines are emphatically analyzed. Then, current methodologies for evaluating the spatiotemporal distribution of nanomedicines are summarized. Finally, the advanced strategies to positively modulate the spatiotemporal distribution of nanomedicines for an optimal tumor therapy are comprehensively reviewed.

Diselenium-linked dimeric prodrug nanomedicine breaking the intracellular redox balance for triple-negative breast cancer targeted therapy

Triple-negative breast cancer (TNBC) has been regarded as the strongest malignancy in cases of breast cancer with a poor prognosis. The development of effective treatment strategies for TNBC has always been an urgent and unmet need. The intracellular redox balance is essential for maintaining TNBC cell malignancy. Disrupting intracellular redox balance by enlarging reactive oxygen species (ROS) generation and facilitating glutathione (GSH) depletion to amplify intracellular oxidative stress may be an alternative strategy to eliminate TNBC cells. However, inducing ROS generation and GSH depletion concurrently may be challenging. Herein, a diselenium linked-dimeric prodrug nanomedicine FA-SeSe-NPs was developed to break the intracellular redox homeostasis for TNBC targeted therapy. The dimeric prodrug was synthesized by conjugating two cucurbitacin B (CuB) molecules via one diselenium bond, which was subsequently assembled with FA-PEG-DSPE to form the final nanomedicine FA-SeSe-NPs. Using the active targeting potential of folic acid (FA), FA-SeSe-NPs could accumulate in tumor tissue with elevated levels and then be specifically internalized by cancer cells. In the high ROS and GSH conditions of TNBC cells, the diselenium bond can specifically respond to ROS to produce selenium free radicals to increase ROS and react with GSH to generate S-Se bond to deplete GSH. The released CuB further induced ROS production in TNBC cells. The diselenium bond and CuB functioned synergistically to amplify oxidative stress to kill the TNBC cells. Here, we provide a promising strategy to disrupt the intracellular redox balance of cancer cells for effective TNBC therapy.

An update on the advances in the field of nanostructured drug delivery systems for a variety of orthopedic applications

Nanotechnology has made significant progress in various fields, including medicine, in recent times. The application of nanotechnology in drug delivery has sparked a lot of research interest, especially due to its potential to revolutionize the field. Researchers have been working on developing nanomaterials with distinctive characteristics that can be utilized in the improvement of drug delivery systems (DDS) for the local, targeted, and sustained release of drugs. This approach has shown great potential in managing diseases more effectively with reduced toxicity. In the medical field of orthopedics, the use of nanotechnology is also being explored, and there is extensive research being conducted to determine its potential benefits in treatment, diagnostics, and research. Specifically, nanophase drug delivery is a promising technique that has demonstrated the capability of delivering medications on a nanoscale for various orthopedic applications. In this article, we will explore current advancements in the area of nanostructured DDS for orthopedic use.

Multifunctional Nanoplatform for NIR-II Imaging-Guided Synergistic Oncotherapy

Tumors are a major public health issue of concern to humans, seriously threatening the safety of people's lives and property. With the increasing demand for early and accurate diagnosis and efficient treatment of tumors, noninvasive optical imaging (including fluorescence imaging and photoacoustic imaging) and tumor synergistic therapies (phototherapy synergistic with chemotherapy, phototherapy synergistic with immunotherapy, etc.) have received increasing attention. In particular, light in the near-infrared second region (NIR-II) has triggered great research interest due to its penetration depth, minimal tissue autofluorescence, and reduced tissue absorption and scattering. Nanomaterials with many advantages, such as high brightness, great photostability, tunable photophysical properties, and excellent biosafety offer unlimited possibilities and are being investigated for NIR-II tumor imaging-guided synergistic oncotherapy. In recent years, many researchers have tried various approaches to investigate nanomaterials, including gold nanomaterials, two-dimensional materials, metal sulfide oxides, polymers, carbon nanomaterials, NIR-II dyes, and other nanomaterials for tumor diagnostic and therapeutic integrated nanoplatform construction. In this paper, the application of multifunctional nanomaterials in tumor NIR-II imaging and collaborative therapy in the past three years is briefly reviewed, and the current research status is summarized and prospected, with a view to contributing to future tumor therapy.

Biodegradable Hydrogen-Bonded Organic Framework for Cytosolic Protein Delivery

Hydrogen-bonded organic frameworks (HOFs) are a novel class of porous nanomaterials that show great potential for intracellular delivery of protein therapeutics. However, the inherent challenges in interfacing protein with HOFs, and the need for spatiotemporally controlling the release of protein within cells, have constrained their therapeutic potential. In this study, we report novel biodegradable hydrogen-bonded organic frameworks, termed DS-HOFs, specially designed for the cytosolic delivery of protein therapeutics in cancer cells. The synthesis of DS-HOFs involves the self-assembly of 4-[tris(4-carbamimidoylphenyl) methyl] benzenecarboximidamide (TAM) and 4,4'-dithiobisbenzoic acid (DTBA), governed by intermolecular hydrogen-bonding interactions. DS-HOFs exhibit high efficiency in encapsulating a diverse range of protein cargos, underpinned by the hydrogen-bonding interactions between the protein residue and DS-HOF subcomponents. Notably, DS-HOFs are selectively degraded in cancer cells triggered by the distinct intracellular reductive microenvironments, enabling an enhanced and selective release of protein inside cancer cells. Additionally, we demonstrate that the efficient delivery of bacterial effector protein DUF5 using DS-HOFs depletes the mutant RAS in cancer cells to prohibit tumor cell growth both in vitro and in vivo. The design of biodegradable HOFs for cytosolic protein delivery provides a powerful and promising strategy to expand the therapeutic potential of proteins for cancer therapy.

Tumor Microenvironment-Responsive One-for-All Molecular-Engineered Nanoplatform Enables NIR-II Fluorescence Imaging-Guided Combinational Cancer Therapy

The activable NIR-based phototheranostic nanoplatform (NP) is considered an efficient and reliable tumor treatment due to its strong targeting ability, flexible controllability, minimal side effects, and ideal therapeutic effect. This work describes the rational design of a second near-infrared (NIR-II) fluorescence imaging-guided organic phototheranostic NP (FTEP-TBFc NP). The molecular-engineered phototheranostic NP has a sensitive response to glutathione (GSH), generating hydrogen sulfide (H2S) gas, and delivering ferrocene molecules in the tumor microenvironment (TME). Under 808 nm irradiation, FTEP-TBFc could not only simultaneously generate fluorescence, heat, and singlet oxygen but also greatly enhance the generation of reactive oxygen species to improve chemodynamic therapy (CDT) and photodynamic therapy (PDT) at a biosafe laser power of 0.33 W/cm2. H2S inhibits the activity of catalase and cytochrome c oxidase (COX IV) to cause the enhancement of CDT and hypothermal photothermal therapy (HPTT). Moreover, the decreased intracellular GSH concentration further increases CDT's efficacy and downregulates glutathione peroxidase 4 (GPX4) for the accumulation of lipid hydroperoxides, thus causing the ferroptosis process. Collectively, FTEP-TBFc NPs show great potential as a versatile and efficient NP for specific tumor imaging-guided multimodal cancer therapy. This unique strategy provides new perspectives and methods for designing and applying activable biomedical phototheranostics.