A tumor-acidity-activated charge-conversional nanogel as an intelligent vehicle for promoted tumoral-cell uptake and drug delivery

Multifunctional Nanosystems with Enhanced Cellular Uptake for Tumor Therapy

Rapid development of nanotechnology provides promising strategies in biomedicine, especially in tumor therapy. In particular, the cellular uptake of nanosystems is not only a basic premise to realize various biomedical applications, but also a fatal factor for determining the final therapeutic effect. Thus, a systematic and comprehensive summary is necessary to overview the recent research progress on the improvement of nanosystem cellular uptake for cancer treatment. According to the process of nanosystems entering the body, they can be classified into three categories. The first segment is to enhance the accumulation and permeation of nanosystems to tumor cells through extracellular microenvironment stimulation. The second segment is to improve cellular internalization from extracellular to intracellular via active targeting. The third segment is to enhance the intracellular retention of therapeutics by subcellular localization. The major factors in the delivery can be utilized to develop multifunctional nanosystems for strengthening the tumor therapy. Ultimately, the key challenges and prospective in the emerging research frontier are thoroughly outlined. This review is expected to provide inspiring ideas, promising strategies and potential pathways for developing advanced anticancer nanosystems in clinical practice.

Tumor-Microenvironment-Responsive Nanomedicine for Enhanced Cancer Immunotherapy

The past decades have witnessed great progress in cancer immunotherapy, which has profoundly revolutionized oncology, whereas low patient response rates and potential immune-related adverse events remain major clinical challenges. With the advantages of controlled delivery and modular flexibility, cancer nanomedicine has offered opportunities to strengthen antitumor immune responses and to sensitize tumor to immunotherapy. Furthermore, tumor-microenvironment (TME)-responsive nanomedicine has been demonstrated to achieve specific and localized amplification of the immune response in tumor tissue in a safe and effective manner, increasing patient response rates to immunotherapy and reducing the immune-related side effects simultaneously. Here, the recent progress of TME-responsive nanomedicine for cancer immunotherapy is summarized, which responds to the signals in the TME, such as weak acidity, reductive environment, high-level reactive oxygen species, hypoxia, overexpressed enzymes, and high-level adenosine triphosphate. Moreover, the potential to combine nanomedicine-based therapy and immunotherapeutic strategies to overcome each step of the cancer-immunity cycle and to enhance antitumor effects is discussed. Finally, existing challenges and further perspectives in this rising field with the hope for improved development of clinical applications are discussed.

Polysaccharide/mesoporous silica nanoparticle-based drug delivery systems: A review

Mesoporous silica nanoparticles (MSNs) have been well-researched in the design and fabrication of advanced drug delivery systems (DDSs) due to their advantages such as good biocompatibility, large specific surface area and pore volume for drug loading, easily surface modification, adjusted size and good thermal/chemical stability. For MSN-based DDSs, gate materials are also necessary. And natural polysaccharides, one kind of the most abundant natural resource, have been widely applied as the "gatekeepers" in MSN-based DDSs. Polysaccharides are cheap and rich in sources with good biocompatibility, and some of them have important biological functions. In this review article, polysaccharides including chitosan, hyaluronic acid, sodium alginate and dextran, et al. are briefly introduced. And the preparation processes and properties such as controlled drug release, cancer targeting and disease diagnosis of functional polysaccharide/MSN-based DDSs are discussed.

Smart Polymeric Delivery System for Antitumor and Antimicrobial Photodynamic Therapy

Photodynamic therapy (PDT) has attracted tremendous attention in the antitumor and antimicrobial areas. To enhance the water solubility of photosensitizers and facilitate their accumulation in the tumor/infection site, polymeric materials are frequently explored as delivery systems, which are expected to show target and controllable activation of photosensitizers. This review introduces the smart polymeric delivery systems for the PDT of tumor and bacterial infections. In particular, strategies that are tumor/bacteria targeted or activatable by the tumor/bacteria microenvironment such as enzyme/pH/reactive oxygen species (ROS) are summarized. The similarities and differences of polymeric delivery systems in antitumor and antimicrobial PDT are compared. Finally, the potential challenges and perspectives of those polymeric delivery systems are discussed.

Synergistic chemo-photothermal cancer therapy of pH-responsive polymeric nanoparticles loaded IR825 and DTX with charge-reversal property

IR825 is a kind of near-infrared (NIR) small molecule cyanine dye and has distinct near-infrared absorbance and excellent thermal conversion performance. Due to poor stability and insufficient therapy efficacy, various nano-systems have been developed as delivery vehicles for NIR dyes to improve their application in tumor treatment. Herein, we developed an intelligent polymer drug vehicle (Mal-PAH-PEG-DMMA/ poly (ethylene imine) - poly(ε-caprolactone) block polymers, MPPD/PEI-PCL) based on pH-responsive charge-reversal to deliver docetaxel (DTX) and photosensitizer (IR825) for chemo-photothermal combination therapy (MPPD@IR825/DTX NPs). MPPD@IR825/DTX NPs could undergo charge conversion in a slightly acidic microenvironment (pH 6.8), resulted in strong electrostatic repulsion to withdraw the shell of the polymer nanoparticles (MPPD), enhanced cellular uptake and increased drug release. MPPD@IR825/DTX NPs demonstrated nanoscale in size with good mono-dispersity and stability, triggered DTX release in response to acid environment and NIR stimulation, in the same time providing excellent photothermal conversion efficiency. In vitro and In vivo experiments confirmed that charge-reversal polymeric nanoparticles improved antitumor efficiency in 4T1 tumor cell modal than non-charge-reversal polymeric nanoparticles. Furthermore, in comparison with chemotherapy or photothermal therapy in a single treatment mode, chemo-photothermal combination therapy of MPPD@IR825/DTX NPs with laser irradiation showed highly efficient tumor ablation. In addition, the polymeric nanoparticles exhibited good biocompatibility and safety. Therefore, the design of charge-reversal polymeric nanoparticles (MPPD@IR825/DTX NPs) provides a new strategy and promising application for targeting and synergistic chemo-photothermal combination therapy.

Micelles Based on Lysine, Histidine, or Arginine: Designing Structures for Enhanced Drug Delivery

Natural amino acids and their derivatives are excellent building blocks of polymers for various biomedical applications owing to the non-toxicity, biocompatibility, and ease of multifunctionalization. In the present review, we summarized the common approaches to designing and constructing functional polymeric micelles based on basic amino acids including lysine, histidine, and arginine and highlighted their applications as drug carriers for cancer therapy. Different polypeptide architectures including linear polypeptides and dendrimers were developed for efficient drug loading and delivery. Besides, polylysine- and polyhistidine-based micelles could enable pH-responsive drug release, and polyarginine can realize enhanced membrane penetration and gas therapy by generating metabolites of nitric oxide (NO). It is worth mentioning that according to the structural or functional characteristics of basic amino acids and their derivatives, key points for designing functional micelles with excellent drug delivery efficiency are importantly elaborated in order to pave the way for exploring micelles based on basic amino acids.

The reversed intra- and extracellular pH in tumors as a unified strategy to chemotherapeutic delivery using targeted nanocarriers

Solid tumors are complex entities, comprising a wide variety of malignancies with very different molecular alterations. Despite this, they share a set of characteristics known as "hallmarks of cancer" that can be used as common therapeutic targets. Thus, every tumor needs to change its metabolism in order to obtain the energy levels required for its high proliferative rates, and these adaptations lead to alterations in extra- and intracellular pH. These changes in pH are common to all solid tumors, and can be used either as therapeutic targets, blocking the cell proton transporters and reversing the pH changes, or as means to specifically deliver anticancer drugs. In this review we will describe how proton transport inhibitors in association with nanocarriers have been designed to block the pH changes that are needed for cancer cells to survive after their metabolic adaptations. We will also describe studies aiming to decrease intracellular pH in cancer using nanoparticles as molecular cages for protons which will be released upon UV or IR light exposure. Finally, we will comment on several studies that have used the extracellular pH in cancer for an enhanced cell internalization and tumor penetration of nanocarriers and a controlled drug delivery, describing how nanocarriers are being used to increase drug stability and specificity.

Recent advances in drug delivery systems for enhancing drug penetration into tumors

The emergence of nanomaterials for drug delivery provides the opportunity to avoid the side effects of systemic drug administration and injury caused by the removal of tumors, delivering great promise for future cancer treatments. However, the efficacy of current nano drugs is not significantly better than that of the original drug treatments. The important reason is that nano drugs enter the tumor vasculature, remaining close to the blood vessels and unable to enter the tumor tissue or tumor cells to complete the drug delivery process. The low efficiency of drug penetration into tumors has become a bottleneck restricting the development of nano-drugs. Herein, we present a systematic overview of recent advances on the design of nano-drug carriers in drug delivery systems for enhancing drug penetration into tumors. The review is organized into four sections: The drug penetration process in tumor tissue includes paracellular and transcellular transport, which is summarized first. Strategies that promote tumor penetration are then introduced, including methods of remodeling the tumor microenvironment, charge inversion, dimensional change, and surface modification of ligands which promote tissue penetration. Conclusion and the prospects for the future development of drug penetration are finally briefly illustrated. The review is intended to provide thoughts for effective treatment of cancer by summarizing strategies for promoting the endocytosis of nano drugs into tumor cells.

Bioresponsive nanomedicines based on dynamic covalent bonds

Trends in the development of modern medicine necessitate the efficient delivery of therapeutics to achieve the desired treatment outcomes through precise spatiotemporal accumulation of therapeutics at the disease site. Bioresponsive nanomedicine is a promising platform for this purpose. Dynamic covalent bonds (DCBs) have attracted much attention in studies of the fabrication of bioresponsive nanomedicines with an abundance of combinations of therapeutic modules and carrier function units. DCB-based nanomedicines could be designed to maintain biological friendly synthesis and site-specific release for optimal therapeutic effects, allowing the complex to retain an integrated structure before accumulating at the disease site, but disassembling into individual active components without compromising function in the targeted organs or tissues. In this review, we focus on responsive nanomedicines containing dynamic chemical bonds that can be cleaved by various specific stimuli, enabling achievement of targeted drug release for optimal therapy in various diseases.

A Cationic Micelle as In Vivo Catalyst for Tumor-Localized Cleavage Chemistry

The emerging strategies of accelerating the cleavage reaction in tumors through locally enriching the reactants is promising. Yet, the applications are limited due to the lack of the tumor-selectivity for most of the reactants. Here we explored an alternative approach to leverage the rate constant by locally inducing an in vivo catalyst. We found that the desilylation-induced cleavage chemistry could be catalyzed in vivo by cationic micelles, and accelerated over 1400-fold under physiological condition. This micelle-catalyzed controlled release platform is demonstrated by the release of a 6-hydroxyl-quinoline-2-benzothiazole derivative (HQB) in two cancer cell lines and a NIR dye in mouse tumor xenografts. Through intravenous injection of a pH-sensitive polymer micelles, we successfully applied this strategy to a prodrug activation of hydroxyl camptothecin (OH-CPT) in tumors. Its "decaging" efficiency is 42-fold to that without cationic micelles-mediated catalysis. This micelle-catalyzed desilylation strategy unveils the potential that micelle may act beyond a carrier but a catalyst for local perturbing or activation.

A Tumor-Penetrating Nanomedicine Improves the Chemoimmunotherapy of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with a low survival rate. The therapeutic effect of chemotherapy and immunotherapy for PDAC is disappointing due to the presence of dense tumor stroma and immunosuppressive cells in the tumor microenvironment (TME). Herein, a tumor-penetrating nanoparticle is reported to modulate the deep microenvironment of PDAC for improved chemoimmunotherapy. The tumor pH-sensitive polymer is synthesized by conjugating N,N-dipentylethyl moieties and monomethoxylpoly(ethylene glycol) onto PAMAM dendrimer, into whose cavity a hydrophobic gemcitabine (Gem) prodrug is accommodated. They self-assemble into nanoparticles (denoted as SPN@Pro-Gem) with the size around 120 nm at neutral pH, but switch into small particles (≈8 nm) at tumor site to facilitate deep delivery of Gem into the tumor parenchyma. In addition to killing cancer cells that resided deeply in the tumor tissue, SPN@Pro-Gem could modulate the TME by reducing the abundance of tumor-associated macrophages and myeloid-derived suppressor cells as well as upregulating the expression level of PD-L1 of tumor cells. This collectively facilitates the infiltration of cytotoxic T cells into the tumors and renders checkpoint inhibitors more effective in previously unresponsive PDAC models. This study reveals a promising strategy for improving the chemoimmunotherapy of pancreatic cancer.

Chitosan nanoparticles as a promising tool in nanomedicine with particular emphasis on oncological treatment

The study describes the current state of knowledge on nanotechnology and its utilization in medicine. The focus in this manuscript was on the properties, usage safety, and potentially valuable applications of chitosan-based nanomaterials. Chitosan nanoparticles have high importance in nanomedicine, biomedical engineering, discovery and development of new drugs. The manuscript reviewed the new studies regarding the use of chitosan-based nanoparticles for creating new release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity of drugs. Nowadays, effective cancer treatment is a global problem, and recent advances in nanomedicine are of great importance. Special attention was put on the application of chitosan nanoparticles in developing new system for anticancer drug delivery. Pre-clinical and clinical studies support the use of chitosan-based nanoparticles in nanomedicine. This manuscript overviews the last progresses regarding the utilization, stability, and bioavailability of drug nanoencapsulation with chitosan and their safety.

Molecular Engineering of High-Performance Aggregation-Induced Emission Photosensitizers to Boost Cancer Theranostics Mediated by Acid-Triggered Nucleus-Targeted Nanovectors

Phototheranostics involving both fluorescence imaging and photodynamic therapy has been recognized to be potentially powerful for cancer treatment by virtue of various intrinsic advantages. However, the state-of-the-art materials in this area are still far from ideal toward practical applications, ascribed to their respective and collective drawbacks, such as inefficient imaging quality, inferior reactive oxygen species (ROS) production, the lack of subcellular-targeting capability, and dissatisfactory delivery. In this paper, these shortcomings are successfully addressed through the integration of finely engineered photosensitizers with aggregation-induced emission (AIE) features and well tailored nanocarrier systems. The yielded AIE NPs simultaneously exhibit broad absorption in the visible-light region, bright near-infrared fluorescence emission, high ROS generation, as well as tumor lysosomal acidity-activated and nucleus-targeted delivery functions, making them promising for precise and efficient phototheranostics. Both in vitro and in vivo evaluations show that the presented nanotheranostic systems bearing good photostability and appreciable biosecurity perform well in fluorescence imaging-guided photodynamic cancer therapy. This study thus not only extends the application scopes of AIE nanomaterials but also offers useful insights into constructing advanced cancer phototheranostics.

Reversing Chemotherapy Resistance by a Synergy between Lysosomal pH-Activated Mitochondrial Drug Delivery and Erlotinib-Mediated Drug Efflux Inhibition

Mitochondrial drug delivery has attracted increasing attention in various mitochondrial dysfunction-associated disorders such as cancer owing to the important role of energy production. Herein, we report a lysosomal pH-activated mitochondrial-targeting polymer nanoparticle to overcome drug resistance by a synergy between mitochondrial delivery of doxorubicin (DOX, an anticancer drug) and erlotinib-mediated inhibition of drug efflux. The obtained nanoparticles, DE-NPs could maintain negative charge and have long blood circulation while undergoing charge reversal at lysosomal pH after internalization by cancer cells. Thereafter, the acidity-activated polycationic and hydrophobic polypeptide domains boost lysosomal escape and mitochondrial-targeting drug delivery, leading to mitochondrial dysfunction, ATP suppression, and cell apoptosis. Moreover, the suppressed ATP supply and erlotinib enabled dual inhibition of drug efflux by DOX-resistant MCF-7/ADR cells, leading to significantly augmented intracellular DOX accumulation and a synergistic anticancer effect with a 17-fold decrease of IC50 relative to DOX. In vivo antitumor study demonstrates that DE-NPs efficiently suppressed the tumor burden in MCF-7/ADR tumor-bearing mice and led to negligible toxicity. This work establishes that a combination of mitochondrial drug delivery and drug efflux inhibition could be a promising strategy for combating multidrug resistance.

2D Core/Shell‐Structured Mesoporous Silicene@Silica for Targeted and Synergistic NIR‐II‐Induced Photothermal Ablation and Hypoxia‐Activated Chemotherapy of Tumors

Silicene nanosheets, the emerging 2D nanomaterial, as the third topology of silicon‐composed materials with distinct physicochemical properties, is a desirable candidate for photothermal‐conversion nanoagent (PTA) and drug‐delivery nanosystems. Inspired by the individual physiochemical properties and structure features of mesoporous silica and 2D silicene, a distinctive 2D core/shell‐structured multifunctional silicon‐composed theranostic nanoplatform (Silicene@Silica) is constructed by coating a mesoporous silica layer onto the surface of 2D silicene nanosheets. The well‐defined mesopores originating from mesoporous silica shell provide the reservoirs for guest drug molecules and the core of silicene produces heat shock upon NIR‐II laser irradiation, aiming to induce the synergistic cancer‐therapeutic modality. Importantly, when AQ4N, hypoxia‐activated prodrug, is introduced into this system, this nanoplatform (Silicene@Silica–AQ4N) exhibits tumor microenvironment (TME)‐responsive and synergistic hyperthermia‐augmented therapeutic bioactivity. Such a nanoplatform can amplify the hypoxia of TME by destroying the tumor microcirculation and then further efficiently activate AQ4N, a DNA affinity agent and topoisomerase II inhibitor. The results reveal that this multifunctional theranostic nanoplatform can efficiently eliminate tumors without recurrence.

A Dual-Responsive Platform Based on Antifouling Dendrimer-CuS Nanohybrids for Enhanced Tumor Delivery and Combination Therapy

Design of stimuli-responsive nanomedicine with enhanced tumor delivery for combination therapy still remains a great challenge. Here, a unique design of an antifouling-dendrimer-based nanoplatform with dual pH- and redox-responsiveness is reported to meet this challenge. First, generation 5 (G5) poly(amidoamine) dendrimers are modified with targeting ligand cyclic arginine-glycine-aspartic acid (RGD) peptide through a polyethylene glycol (PEG) spacer and zwitterion of thiolated N,N-dimethyl-cysteamine-carboxybetaine (CBT) via pH-responsive benzoicimine bond to form G5.NH₂ PEGRGDCBT conjugates. Then, doxorubicin (DOX) is linked to the functional G5 dendrimers through a redox-responsive disulfide bond, followed by entrapment of CuS nanoparticles within the dendrimers. The created functional dendrimer-CuS nanohybrids with a CuS core size of 3.6 nm display a good antifouling property and excellent photothermal conversion property in the second near-infrared window. In addition, the neutral surface charge of the nanohybrids is able to be switched to be positive in the tumor region with slightly acidic microenvironment due to the break of benzoicimine bond to promote their intracellular uptake, while the redox-sensitive disulfide bond affords the fast release of the conjugated DOX within tumor cells to exert its therapeutic effect. Taken together with the CuS cores, the created dendrimer-CuS nanohybrids enable enhanced combination chemotherapy and photothermal therapy of tumors.

Inhibitory Effect of pH-Responsive Nanogel Encapsulating Ginsenoside CK against Lung Cancer

Ginsenoside CK is one of the intestinal bacterial metabolites of ginsenoside prototype saponins, such as ginsenoside Rb1, Rb2, Rc, and Rd. Poor water solubility and low bioavailability have limited its application. The nanogel carriers could specifically deliver hydrophobic drugs to cancer cells. Therefore, in this study, a nanogel was constructed by the formation of Schiff base bonds between hydrazide-modified carboxymethyl cellulose (CMC-NH₂) and aldehyde-modified β-cyclodextrin (β-CD-CHO). A water-in-oil reverse microemulsion method was utilized to encapsulate ginsenoside CK via the hydrophobic cavity of β-CD. β-CD-CHO with a unique hydrophobic cavity carried out efficient encapsulation of CK, and the drug loading and encapsulation efficiency were 16.4% and 70.9%, respectively. The drug release of CK-loaded nanogels (CK-Ngs) in vitro was investigated in different pH environments, and the results showed that the cumulative release rate at pH 5.8 was 85.5% after 140 h. The methylthiazolyldiphenyl-tetrazolium bromide (MTT) toxicity analysis indicated that the survival rates of A549 cells in CK-Ngs at 96 h was 2.98% compared to that of CK (11.34%). In vivo animal experiments exhibited that the inhibitory rates of CK-Ngs against tumor volume was 73.8%, which was higher than that of CK (66.1%). Collectively, the pH-responsive nanogel prepared herein could be considered as a potential nanocarrier for CK to improve its antitumor effects against lung cancer.

Peptide modified polycations with pH triggered lytic activity for efficient gene delivery

Endo/lysosome entrapment is the key barrier for gene delivery using synthetic polycations. Although the introduction of a membrane-lytic peptide into polycations could facilitate efficient endo/lysosome release and improve gene delivery efficiency, it is always accompanied by serious safety concerns. In this work, the widely used polycations, poly(2-dimethylaminoethyl methacrylate (PDMAEMA), poly(l-lysine) (PLL) and polyethylenimine (PEI), are modified with a pH-sensitive peptide (C6M3) with selective lytic activity to produce three functional polycations to address the issue of endo/lysosome entrapment and facilitate efficient gene transfer. Hemolysis study shows that the functionalized polycations show good biocompatibility toward red blood cells at neutral pH, and exhibit potent membrane lysis activity under acidic conditions, which are both on-demand for the ideal gene carriers. In vitro transfection studies demonstrate that the peptide modified polycations mediate promising gene delivery efficiency with the luciferase plasmid and the green fluorescence protein plasmid in HeLa cells compared to the parent polycations. Owing to the facile preparation and selective lysis activity of the C6M3 modified polycations, these smart gene vectors may be good candidates for the transfer of various nucleic acids and further clinical gene therapy.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Recent Advances in Design of Functional Biocompatible Hydrogels for Bone Tissue Engineering

Bone related diseases have caused serious threats to human health owing to their complexity and specificity. Fortunately, owing to the unique 3D network structure with high aqueous content and functional properties, emerging hydrogels are regarded as one of the most promising candidates for bone tissue engineering, such as repairing cartilage injury, skull defect, and arthritis. Herein, various design strategies and synthesis methods (e.g., 3D‐printing technology and nanoparticle composite strategy) are introduced to prepare implanted hydrogel scaffolds with tunable mechanical strength, favorable biocompatibility, and excellent bioactivity for applying in bone regeneration. Injectable hydrogels based on biocompatible materials (e.g., collagen, hyaluronic acid, chitosan, polyethylene glycol, etc.) possess many advantages in minimally invasive surgery, including adjustable physicochemical properties, filling irregular shapes of defect sites, and on‐demand release drugs or growth factors in response to different stimuli (e.g., pH, temperature, redox, enzyme, light, magnetic, etc.). In addition, drug delivery systems based on micro/nanogels are discussed, and its numerous promising designs used in the application of bone diseases (e.g., rheumatoid arthritis, osteoarthritis, cartilage defect) are also briefed in this review. Particularly, several key factors of hydrogel scaffolds (e.g., mechanical property, pore size, and release behavior of active factors) that can induce bone tissue regeneration are also summarized in this review. It is anticipated that advanced approaches and innovative ideas of bioactive hydrogels will be exploited in the clinical field and increase the life quality of patients with the bone injury.

Strategies and challenges to improve the performance of tumor-associated active targeting

Over the past decade, nanoparticle-based drug delivery systems have been extensively explored. However, the average tumour enrichment ratio of passive targeting systems corresponds to only 0.7% due to the nonspecific uptake by normal organs and poor selective retention in tumours. The therapeutic specificity and efficacy of nano-medicine can be enhanced by equipping it with active targeting ligands, although it is not possible to ignore the recognition and clearance of the reticuloendothelial system (RES) caused by targeting ligands. Given the complexity of the systemic circulation environment, it is necessary to carefully consider the hydrophobicity, immunogenicity, and electrical property of targeting ligands. Thus, for an active targeting system, the targeting ligands should be shielded in blood circulation and de-shielded in the tumour region for enhanced tumour accumulation. In this study, strategies for improving the performance of active targeting ligands are introduced. The strategies include irreversible shielding, reversible shielding, and methods of modulating the multivalent interactions between ligands and receptors. Furthermore, challenges and future developments in designing active ligand targeting systems are also discussed.

Antitumor Effect of Hyperoside Loaded in Charge Reversed and Mitochondria-Targeted Liposomes

Introduction

Hyperoside (HYP), a flavonol glycoside compound, has been shown to significantly inhibit the proliferation of malignant tumors. Mitochondria serve as both “energy factories” and “suicide weapon stores” of cells. Targeted delivery of cytotoxic drugs to the mitochondria of tumor cells and tumor vascular cells is a promising strategy to improve the efficacy of chemotherapy.

Objective

We report a novel dual-functional liposome system possessing both extracellular charge reversal and mitochondrial targeting properties to enhance drug accumulation in mitochondria and trigger apoptosis of cancer cells.

Methods

L-lysine was used as a linker to connect 2,3-dimethylmaleic anhydride (DMA) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) to yield a new compound, DSPE-Lys-DMA (DLD). Then, DLD was mixed with other commercially available lipids to form charge reversed and mitochondria-targeted liposomes (DLD-Lip). The size, morphology, zeta potential, serum stability, and protein adsorption of the HYP loaded DLD-Lip (HYP/DLD-Lip) were measured. The release profile, cellular uptake, in vitro and in vivo toxicity, and anticancer activity of HYP/DLD-Lip were investigated.

Results

The results showed that the mean diameter of the liposomes was less than 200 nm. The zeta potential of the liposomes was negative at pH 7.4. However, the zeta potential was positive at weak acidic pH values with the cleavage of the DMA amide. The charge reversion of HYP/DLD-Lip facilitated the cellular internalization and mitochondrial accumulation for enhanced antitumor effect. The strongest tumor growth inhibition (TGI 88.79%) without systemic toxicity was observed in DLD/HYP-Lips-treated CBRH-7919 tumor xenograft BALB/C mice.

Conclusion

The charge reversed and mitochondria-targeted liposomes represented a promising anticancer drug delivery system for enhanced anticancer therapeutic efficacy.

Mitochondrion-specific dendritic lipopeptide liposomes for targeted sub-cellular delivery

The mitochondrion is an important sub-cellular organelle responsible for the cellular energetic source and processes. Owing to its unique sensitivity to heat and reactive oxygen species, the mitochondrion is an appropriate target for photothermal and photodynamic treatment for cancer. However, targeted delivery of therapeutics to mitochondria remains a great challenge due to their location in the sub-cellular compartment and complexity of the intracellular environment. Herein, we report a class of the mitochondrion-targeted liposomal delivery platform consisting of a guanidinium-based dendritic peptide moiety mimicking mitochondrion protein transmembrane signaling to exert mitochondrion-targeted delivery with pH sensitive and charge-reversible functions to enhance tumor accumulation and cell penetration. Compared to the current triphenylphosphonium (TPP)-based mitochondrion targeting system, this dendritic lipopeptide (DLP) liposomal delivery platform exhibits about 3.7-fold higher mitochondrion-targeted delivery efficacy. Complete tumor eradication is demonstrated in mice bearing 4T1 mammary tumors after combined photothermal and photodynamic therapies delivered by the reported DLP platform.

Multifunctional nanoplatforms co-delivering combinatorial dual-drug for eliminating cancer multidrug resistance

Clinically, the primary cause of chemotherapy failure belongs to the occurrence of cancer multidrug resistance (MDR), which directly leads to the recurrence and metastasis of cancer along with high mortality. More and more attention has been paid to multifunctional nanoplatform-based dual-therapeutic combination to eliminate resistant cancers. In addition to helping both cargoes improve hydrophobicity and pharmacokinetic properties, increase bioavailability, release on demand and enhance therapeutic efficacy with low toxic effects, these smart co-delivery nanocarriers can even overcome drug resistance. Here, this review will not only present different types of co-delivery nanocarriers, but also summarize targeted and stimuli-responsive combination nanomedicines. Furthermore, we will focus on the recent progress in the co-delivery of dual-drug using such intelligent nanocarriers for surmounting cancer MDR. Whereas it remains to be seriously considered that there are some knotty issues in the fight against MDR of cancers via using co-delivery nanoplatforms, including limited intratumoral retention, the possible changes of combinatorial ratio under complex biological environments, drug release sequence from the nanocarriers, and subsequent free-drug resistance after detachment from the nanocarriers. It is hoped that, with the advantage of continuously developing nanomaterials, two personalized therapeutic agents in combination can be better exploited to achieve the goal of cooperatively combating cancer MDR, thus advancing the time to clinical transformation.

Nanoplatforms for Targeted Stimuli-Responsive Drug Delivery: A Review of Platform Materials and Stimuli-Responsive Release and Targeting Mechanisms

To achieve the promise of stimuli-responsive drug delivery systems for the treatment of cancer, they should (1) avoid premature clearance; (2) accumulate in tumors and undergo endocytosis by cancer cells; and (3) exhibit appropriate stimuli-responsive release of the payload. It is challenging to address all of these requirements simultaneously. However, the numerous proof-of-concept studies addressing one or more of these requirements reported every year have dramatically expanded the toolbox available for the design of drug delivery systems. This review highlights recent advances in the targeting and stimuli-responsiveness of drug delivery systems. It begins with a discussion of nanocarrier types and an overview of the factors influencing nanocarrier biodistribution. On-demand release strategies and their application to each type of nanocarrier are reviewed, including both endogenous and exogenous stimuli. Recent developments in stimuli-responsive targeting strategies are also discussed. The remaining challenges and prospective solutions in the field are discussed throughout the review, which is intended to assist researchers in overcoming interdisciplinary knowledge barriers and increase the speed of development. This review presents a nanocarrier-based drug delivery systems toolbox that enables the application of techniques across platforms and inspires researchers with interdisciplinary information to boost the development of multifunctional therapeutic nanoplatforms for cancer therapy.

NO-releasing polypeptide nanocomposites reverse cancer multidrug resistance via triple therapies

Multidrug resistance (MDR) induced by the overexpression of P-glycoprotein (P-gp) transporters mainly leads to chemotherapy (CT) failure. Herein, a NIR/pH dual-sensitive charge-reversal polypeptide nanocomposite (PDA-PLC) was developed for co-delivering a nitric oxide (NO) donor and doxorubicin (DOX). Under near-infrared (NIR) irradiation, the released high-concentration of NO gas inhibited the P-gp expression to sensitize the chemotherapeutic medicine DOX and assisted photothermal therapy (PTT) to eradicate cancer cells without skin scarring. Further, the distinctive charge-reversal capacity of PDA-PLC significantly facilitated cellular uptake in the tumor acidic microenvironment (pH 6.8) and enhanced its stability in the physiological environment (pH 7.4). This DOX-loading polypeptide nanocomposite (PDA-PLC/DOX) provides an effective strategy for the PTT-NO-CT triple-combination therapy to overcome MDR STATEMENT OF SIGNIFICANCE: Multidrug resistance (MDR) has been considered to be the paramount factor of chemotherapy (CT) failure in cancer. In this work, an NIR/pH dual-sensitive charge-reversal polypeptide nanomedicine (PDA-PLC/DOX) was developed to overcome MDR through the triple combination therapy of photothermal therapy (PTT), NO gas therapy, and CT. The distinctive charge-reversal capacity of PDA-PLC/DOX significantly facilitated cellular uptake in the tumor acidic microenvironment (pH 6.8) and enhanced its stability in the physiological environment (pH 7.4), while the NIR trigger-released NO gas greatly inhibited the expression of P-gp and synergistically enhanced PTT and CT efficacy. This polypeptide nanocomposite PDA-PLC/DOX provides an effective strategy of using the PTT-NO-CT triple combination therapy with charge-reversal property to completely eradicate the MCF-7/ADR tumor.

A pH-sensitive nanoagent self-assembled from a highly negatively-charged phthalocyanine with excellent biosafety for photothermal therapy

Photothermal therapy (PTT) is a promising strategy for cancer treatment. However, the development of highly efficient photothermal agents with excellent biosafety, particularly with low liver retention, is very meaningful for clinical applications, but it is also challenging. We herein prepared a pH-sensitive nanoagent (NanoPc3) by the self-assembly of a zinc(ii) phthalocyanine substituted with hexadeca-sulphonates linked by hydrazone bonds for photoacoustic imaging and PTT. Due to the highly negative surface potential (-30.80 mV in water), NanoPc3 could effectively escape the phagocytosis of the reticuloendothelial system and be rapidly cleared from normal tissues, leading to little accumulation in the liver and excellent biosafety. The highly negatively-charged NanoPc3 changed into nearly neutral nanoparticles (NanoPc3H) under slightly acidic conditions, resulting in enhanced cellular uptake and retention time in tumor tissues. Moreover, the tumor of H22 tumor-bearing mice treated with NanoPc3 almost disappeared, suggesting an outstanding photothermal antitumor effect. NanoPc3 also hardly showed skin phototoxicity under irradiation. Its excellent antitumor effect and biosafety make NanoPc3 highly promising in clinical applications. This work will provide a new strategy for the design of tumor-targeted photothermal nanoagents with high biosafety.

Cyclic Anhydrides as Powerful Tools for Bioconjugation and Smart Delivery

Cyclic anhydrides are potent tools for bioconjugation; therefore, they are broadly used in the functionalization of biomolecules and carriers. The pH-dependent stability and reactivity, as well as the physical properties, can be tuned by the structure of the cyclic anhydride used; thus, their application in smart delivery systems has become very important. This review intends to cover the last updates in the use of cyclic anhydrides as pH-sensitive linkers, their differences in reactivity, and the latest applications found in bioconjugation chemistry or chemical biology, and when possible, in drug delivery.

Smart transformable nanomedicines for cancer therapy

Despite that great progression has been made in nanoparticulate drug delivery systems (nano-DDS), multiple drug delivery dilemmas still impair the delivery efficiency of nanomedicines. Rational design of smart transformable nano-DDS based on the in vivo drug delivery process represents a promising strategy for overcoming delivery obstacle of nano-DDS. In recent years, tremendous efforts have been devoted to developing smart transformable anticancer nanomedicines. Herein, we provide a review to outline the advances in this emerging field. First, smart size-reducible nanoparticles (NPs) for deep tumor penetration are summarized, including carrier degradation-induced, protonation-triggered and photobleaching-induced size reduction. Second, emerging transformable nanostructures for various therapeutic applications are discussed, including prolonging tumor retention, reversing drug-resistance, inhibiting tumor metastasis, preventing tumor recurrence and non-pharmaceutical therapy. Third, shell-detachable nanocarriers are introduced, focusing on chemical bonds breaking-initiated, charge repulsion-mediated and exogenous stimuli-triggered shell detachment approaches. Finally, the future perspectives and challenges of transformable nanomedicines in clinical cancer therapy are highlighted.

Optimal synthesis of polyelectrolyte nanogels by electrostatic assembly directed polymerization for dye loading and release

Polyelectrolyte (PE) nanogels which combine features of nanogels and polyelectrolytes have attracted significant attention as outstanding nano-carriers. However, and crucially, any large-scale application of PE nanogels can only materialize when an efficient production method is available. We recently developed such a robust approach, namely Electrostatic Assembly Directed Polymerization (EADP), in which ionic monomers are polymerized together with cross-linker in the presence of a polyion-neutral diblock copolymer as template. Although EADP achieves efficient and scalable preparation of diverse PE nanogels, the essential factors for the optimal and controlled synthesis of nanogels have remained elusive. In this article, we investigate systematically the effects of pH, salt concentration, and cross-linker fractions on the formation and properties of a PDMAEMA nanogel prepared with PAA-b-PEO as the template. We find that the electrostatic interaction between the building blocks is crucial to obtain assembly-controlled polymerization, and we establish preferred pH, salt concentration and cross-linker fractions. The obtained PDMAEMA nanogel exhibits dual-responses to pH and salt, which allow manipulation of the positive charges of the nanogels for selective loading and controlled release of anionic substances; we demonstrate this with an anionic dye. The study presented here fully addresses the process parameters of EADP regarding optimal and controlled preparation of PE nanogels, which should allow exploration of their potential vis-a-vis a variety of applications.

Multivalent dextran hybrids for efficient cytosolic delivery of biomolecular cargoes

The development of novel biotherapeutics based on peptides and proteins is often limited to extracellular targets, because these molecules are not able to reach the cytosol. In recent years, several approaches were proposed to overcome this limitation. A plethora of cell-penetrating peptides (CPPs) was developed for cytoplasmic delivery of cell-impermeable cargo molecules. For many CPPs, multimerization or multicopy arrangement on a scaffold resulted in improved delivery but also higher cytotoxicity. Recently, we introduced dextran as multivalent, hydrophilic polysaccharide scaffold for multimerization of cell-targeting cargoes. Here, we investigated covalent conjugation of a CPP to dextran in multiple copies and assessed the ability of resulted molecular hybrid to enter the cytoplasm of mammalian cells without largely compromising cell viability. As a CPP, we used a novel, low-toxic cationic amphiphilic peptide L17E derived from M-lycotoxin. Here, we show that cell-penetrating properties of L17E are retained upon multivalent covalent linkage to dextran. Dextran-L17E efficiently mediated cytoplasmic translocation of an attached functional peptide and a peptide nucleic acid (PNA). Moreover, a synthetic route was established to mask the lysine side chains of L17E with a photolabile protecting group thus opening avenues for light-triggered activation of cellular uptake.

Iron-crosslinked Rososome with robust stability and high drug loading for synergistic cancer therapy

Development of liposomal nanomedicine with robust stability, high drug loading and synergistic efficacy is a promising strategy for effective cancer therapy. Here, we present an iron-crosslinked rosmarinic liposome (Rososome) which can load high contents of drugs (including 25.8% rosmarinic acid and 9.04% doxorubicin), keep stable in a high concentration of anionic detergent and exhibit synergistic anti-cancer efficacy. The Rososomes were constructed by rosmarinic acid-lipid conjugates which not only work synergistically with doxorubicin by producing reactive oxygen species but also provide catechol moieties for the iron cross-linkages. The cross-linkages can lock the payloads tightly, endowing the crosslinked Rososome with better stability and pharmacokinetics than its non-crosslinked counterpart. On the syngeneic mouse model of breast cancer, the iron-crosslinked Rososomes exhibit better anticancer efficacy than free rosmarinic acid, doxorubicin, non-crosslinked Rososome and commercial liposomal formulation of doxorubicin (DOXIL). This study introduces a novel strategy for the development of liposomes with robust stability, high drug loading and synergistic anti-cancer efficacy.

Gold nanoparticle-guarded large-pore mesoporous silica nanocomposites for delivery and controlled release of cytochrome c

Efficient delivery of active proteins to specific cells and organs is one of the most important issues in medical applications. However, in most cases, proteins without appropriate carriers face numerous barriers when delivered to the target, due to their unsatisfied properties, such as poor stability, short half-life, and low membrane permeability. Herein, we have presented a large-pore mesoporous silica nanoparticle (LPMSN)-based protein delivery system. LPMSNs were obtained with ethyl acetate as a pore expander. A 2,3-dimethylmaleamic acid-containing silane coupling agent was modified on LPMSNs to provide pH-triggered charge reversal. After Cytochrome c (CC) was encapsulated in the large pores of LPMSNs, amino-terminated polyethylene glycol-modified gold nanoparticles (AuNPs) served as gateguards to cap the tunnels of LPMSNs and to avoid the leakage of CC. Above nanocomposites exhibited the capability to deliver active CC into cancer cells, charge reversal-induced protein release, as well as to initiate the apoptosis machinery of cancer cells in vitro. Importantly, the nanocomposites significantly inhibited tumor growth and extended survival rate without obvious side effects. This study provides a smart and efficient protein delivery platform with good safety profiles for efficacious tumor protein therapy in vivo.

The application of nanoparticles in cancer immunotherapy: Targeting tumor microenvironment

The tumor development and metastasis are closely related to the structure and function of the tumor microenvironment (TME). Recently, TME modulation strategies have attracted much attention in cancer immunotherapy. Despite the preliminary success of immunotherapeutic agents, their therapeutic effects have been restricted by the limited retention time of drugs in TME. Compared with traditional delivery systems, nanoparticles with unique physical properties and elaborate design can efficiently penetrate TME and specifically deliver to the major components in TME. In this review, we briefly introduce the substitutes of TME including dendritic cells, macrophages, fibroblasts, tumor vasculature, tumor-draining lymph nodes and hypoxic state, then review various nanoparticles targeting these components and their applications in tumor therapy. In addition, nanoparticles could be combined with other therapies, including chemotherapy, radiotherapy, and photodynamic therapy, however, the nanoplatform delivery system may not be effective in all types of tumors due to the heterogeneity of different tumors and individuals. The changes of TME at various stages during tumor development are required to be further elucidated so that more individualized nanoplatforms could be designed.

A Sequentially Responsive Nanosystem Breaches Cascaded Bio-barriers and Suppresses P-Glycoprotein Function for Reversing Cancer Drug Resistance

Cancer chemotherapy is challenged by multidrug resistance (MDR) mainly attributed to overexpressed transmembrane efflux pump P-glycoprotein (P-gp) in cancer cells. Improving drug delivery efficacy while co-delivering P-gp inhibitors to suppress drug efflux is an often-used nanostrategy for combating MDR, which is however challenged by cascaded bio-barriers en route to cancer cells and P-gp inhibitors' adverse effects. To effectively breach the cascaded bio-barriers while avoiding P-gp inhibitors' adverse effects, a stealthy, sequentially responsive doxorubicin (DOX) delivery nanosystem (RCMSNs) is fabricated, composed of an extracellular-tumor-acidity-responsive polymer shell (PEG-b-PLLDA), pH/redox dual-responsive mesoporous silica nanoparticle-based carriers (MSNs-SS-Py), and cationic β-cyclodextrin-PEI (CD-PEI) gatekeepers. The PEG-b-PLLDA corona makes RCMSNs stealthy with prolonged blood circulation time. Once tumors are reached, extracellular acidity degrades PEG-b-PLLDA, reversing nanosystem's surface charges to be positive, which drastically improves RCMSNs' tumor accumulation, penetration, and cellular internalization. Within cancer cells, CD-PEI gatekeepers detach to allow DOX unloading in response to intracellular acidity and glutathione and functionally act as a P-gp inhibitor, dampening P-gp's efflux activity by impairing ATP production. Thus, the resultant high-efficacy drug delivery along with reduced P-gp function cooperatively reverses MDR in vitro. Importantly, in preclinical tumor models, DOX@RCMSNs potently suppress MDR tumor growth without eliciting systemic toxicity, demonstrating their potential of clinical translation.

Influence of Buffers, Ionic Strength, and pH on the Volume Phase Transition Behavior of Acrylamide-Based Nanogels

The use of covalently crosslinked nanogels for applications in biology and medicine is dependent on their properties and characteristics, which often change because of the biological media involved. Understanding the role of salts, ionic strength and pH in altering specific properties is key to progress in this area. We studied the effect of both chemical structure and media environment on the thermoresponsive behavior of nanogels. A small library of methylenebisacrylamide (MBA) crosslinked nanogels were prepared using N-isopropylacrylamide (NIPAM) or N-n-propylacrylamide (NPAM), in combination with functional monomers N-hydroxyethylacrylamide (HEAM) and N-acryloyl-l-proline (APrOH). The thermoresponsive properties of nanogels were evaluated in phosphate buffer, tris-acetate buffer and Ringer HEPES, with varying concentrations and ionic strengths. The presence of ions facilitates the phase separation of nanogels, and this “salting-out” effect strongly depends on the electrolyte concentration as well as the specificity of individual anions, e.g., their positions in the Hofmeister series. A subtle change in the chemical structure of the side chain of the monomer from NIPAM to NPAM leads to a reduction of the volume phase transition temperature (VPTT) value by ~10 °C. The addition of hydrophilic comonomers such as HEAM, on the other hand, causes a ~20 °C shift in VPTT to higher values. The data highlight the significant role played by the chemical structure of the monomers used, with hydrophobicity and rigidity closely interlinked in determining thermoresponsive behavior. Furthermore, the volume phase transition temperature (VPTT) of nanogels copolymerized with ionizable APrOH comonomer can be tailored by changes in the pH of buffer solutions. This temperature-controlled phase transition is driven by intricate interplay involving the entropy of mixing, electrostatic interactions, conformational transitions, and structural rigidity. These results highlight the importance of understanding the physiochemical properties and behavior of covalently crosslinked nanogels in a biological environment prior to their applications in life-science, such as temperature/pH-triggered drug delivery systems.

Dual-responsive doxorubicin-loaded nanomicelles for enhanced cancer therapy

BACKGROUND

The enhancement of tumor retention and cellular uptake of drugs are important factors in maximizing anticancer therapy and minimizing side effects of encapsulated drugs. Herein, a delivery nanoplatform, armed with a pH-triggered charge-reversal capability and self-amplifiable reactive oxygen species (ROS)-induced drug release, is constructed by encapsulating doxorubicin (DOX) in pH/ROS-responsive polymeric micelle.

RESULTS

The surface charge of this system was converted from negative to positive from pH 7.4 to pH 6.8, which facilitated the cellular uptake. In addition, methionine-based system was dissociated in a ROS-rich and acidic intracellular environment, resulting in the release of DOX and α-tocopheryl succinate (TOS). Then, the exposed TOS segments further induced the generation of ROS, leading to self-amplifiable disassembly of the micelles and drug release.

CONCLUSIONS

We confirms efficient DOX delivery into cancer cells, upregulation of tumoral ROS level and induction of the apoptotic capability in vitro. The system exhibits outstanding tumor inhibition capability in vivo, indicating that dual stimuli nano-system has great potential to function as an anticancer drug delivery platform.

100th Anniversary of Macromolecular Science Viewpoint: Biological Stimuli-Sensitive Polymer Prodrugs and Nanoparticles for Tumor-Specific Drug Delivery

The development of smart polymer vehicles to carry and release cytotoxic drugs to tumor tissues and cells while reducing the exposure of drugs in the blood and healthy organs is a highly challenging task with continuously growing interest from multiple fields, including polymer science, pharmaceutical science, nanotechnology, and clinical oncology. Inspired by the unique tumor microenvironment, such as mild acidity and overexpressed enzymes, functional polymer prodrugs and nanoparticles with reversible charge, detachable PEG shell, activatable ligand, and switchable size have been designed to enhance tumor deposition, tumor penetration, tumor cell uptake, and tumoral drug release. Utilizing biological signals inside tumor cells, such as acidic endo/lysosomal pH, elevated glutathione levels, and reactive oxygen species, responsive polymer prodrugs and nanoparticles with good extracellular stability but fast intracellular disintegration have been engineered for specific intracellular drug release. These biological stimuli-sensitive polymer prodrugs and nanoparticles have shown superior specificity and therapeutic efficacy to nonsensitive counterparts and, in certain cases, even clinically approved systems in varying tumor models. In this Viewpoint, design strategies and recent advances of biological stimuli-responsive polymer prodrugs and nanoparticles for tumor-specific drug delivery will be highlighted, and their challenges and future perspectives will be discussed.

Synergistic regulation of longitudinal and transverse relaxivity of extremely small iron oxide nanoparticles (ESIONPs) using pH-responsive nanoassemblies

Extremely small iron oxide nanoparticles (ESIONPs), as a kind of the special T1 magnetic resonance imaging (MRI) contrast agent that can provide T1 contrasting enhancement since their magnetically disordered shells are dominant compared to their magnetic cores and have powerful potential for constructing stimuli-responsive contrast agents (CAs) to realize precise the tumor diagnosis with high specificity and sensitivity. The stimuli-responsive function of ESIONPs-based CAs can be directly endowed through the synergistic regulation of the longitudinal and transverse relaxivity (r1 and r2) of ESIONPs. However, the systematical investigation for the synergistic regulation of r1 and r2 of ESIONPs is quite lacking. Herein, based on the relaxivity theories, three kinds of ESIONPs-based nanoassemblies with pH-responsiveness were designed and constructed to explore the possibility of various synergistic regulations on r1 and r2. When three kinds of ESIONPs-based nanoassemblies were converted to dissociated ones under a weak acid environment, ESIONPs micelle could realize a synergistic regulation of the single r2 decrease along with the stable r1, while gold nanoparticles-ESIONPs (AuNPs-ESIONPs) vesicle could provide a synergistic regulation comprising the single r1 increase along with the stable r2, and ESIONPs vesicle could offer a synergistic regulation involving the r2 decrease together with the r1 increase. Moreover, all the synergistic regulations on r1 and r2 were efficient strategies to fabricate ESIONPs-based CAs with the stimuli-responsive function. These systematic and feasible synergistic regulations of r1 and r2 may guide and promote the development of ESIONPs-based stimuli-responsive CAs for the highly sensitive and specific tumor diagnosis.