NIR‐Light‐Activated Combination Therapy with a Precise Ratio of Photosensitizer and Prodrug Using a Host–Guest Strategy

Co-Assembled Nanoparticles toward Multi-Target Combinational Therapy of Alzheimer's Disease by Making Full Use of Molecular Recognition and Self-Assembly

The complex pathologies in Alzheimer's disease (AD) severely limit the effectiveness of single-target pharmic interventions, thus necessitating multi-pronged therapeutic strategies. While flexibility is essentially demanded in constructing such multi-target systems, for achieving optimal synergies and also accommodating the inherent heterogeneity within AD. Utilizing the dynamic reversibility of supramolecular strategy for conferring sufficient tunability in component substitution and proportion adjustment, amphiphilic calixarenes are poised to be a privileged molecular tool for facilely achieving function integration. Herein, taking β-amyloid (Aβ) fibrillation and oxidative stress as model combination pattern, a supramolecular multifunctional integration is proposed by co-assembling guanidinium-modified calixarene with ascorbyl palmitate and loading dipotassium phytate within calixarene cavity. Serial pivotal events can be simultaneously addressed by this versatile system, including 1) inhibition of Aβ production and aggregation, 2) disintegration of Aβ fibrils, 3) acceleration of Aβ metabolic clearance, and 4) regulation of oxidative stress, which is verified to significantly ameliorate the cognitive impairment of 5×FAD mice, with reduced Aβ plaque content, neuroinflammation, and neuronal apoptosis. Confronted with the extremely intricate clinical realities of AD, the strategy presented here exhibits ample adaptability for necessary alterations on combinations, thereby may immensely expedite the advancement of AD combinational therapy through providing an exceptionally convenient platform.

Recent Advances in Photosensitizer Materials for Light-Mediated Tumor Therapy

Photodynamic therapy (PDT) as an emerging therapeutic method has drawn much attention in the treatment field for cancer. Photosensitizer, which can convert photon energy into cytotoxic species under light irradiation, is the core component in PDT. The design of photosensitizers still faces problems of light absorption, targeting, penetration and oxygen dependence. With the rapid progress of material science, various photosensitizers have been developed to produce cytotoxic species for treatment of tumor with high selectivity, safety, and noninvasiveness. Besides, the applications of photosensitizers have been expanded to diverse cancer treatments such as drug release, optogenetics and immune checkpoint blockade. In this review, we summarize the recent advances of photosensitizers in various therapeutic methods for cancer. Prevailing challenges and further prospects associated with photosensitizers are also discussed.

Supramolecular 3 in 1: A Lubrication and Co-Delivery System for Synergistic Advanced Osteoarthritis Therapy

The complexity, heterogeneity, and drug resistance of diseases necessitate a shift in therapeutic paradigms from monotherapy to combination therapy, which could augment treatment efficiency. Effective treatment of advanced osteoarthritis (OA) requires addressing three key factors contributing to its deterioration: chronic joint inflammation, lubrication dysfunction, and cartilage-tissue degradation. Herein, we present a supramolecular nanomedicine of multifunctionality via molecular recognition and self-assembly. The employed macrocyclic carrier, zwitterion-modified cavitand (CV-2), not only accurately loads various drugs but also functions as a therapeutic agent with lubricating properties for the treatment of OA. Kartogenin (KGN), a drug for articular cartilage regeneration and protection, and flurbiprofen (FP), an anti-inflammatory agent, were coloaded onto CV-2 assembly, forming a supramolecular nanomedicine KGN&FP@CV-2. The three-in-one combination therapy of KGN&FP@CV-2 addresses the three pathological features for treating OA collectively, and thus provides long-term therapeutic benefits for OA through sustained drug release and intrinsic lubrication in vivo. The multifunctional integration of macrocyclic delivery and therapeutics provides a simple, flexible, and universal platform for the synergistic treatment of diseases involving multiple drugs.

Deliver on a Promise: Hydrogen-Bonded Polymer Nanomedicine with a Precise Ratio of Chemodrug and Photosensitizer for Intelligent Cancer Therapy

The outcomes of combined cancer therapy are largely related to loading content and contribution of each therapeutic agent; however, fine-tuning the ratio of two coloaded components toward precise cancer therapy is a great challenge and still remains in its infancy. We herein develop a supramolecular polymer scaffold to optimize the coloading ratio of chemotherapeutic agent and photosensitizer through hydrogen-bonding (H-bonding) interaction, for maximizing the efficacy of intelligent cancer chemo/photodynamic therapies (CT/PDT). To do so, we first synthesize a thymine (THY)-functionalized tetraphenylporphyrin photosensitizer (i.e., TTPP), featuring the same molecular configuration of H-bonding array with chemotherapeutic carmofur (e.g., 1-hexylcarbamoyl-5-fluorouracil, HCFU). Meanwhile, a six-arm star-shaped amphiphilic polymer vehicle P(DAPA-co-DPMA-co-OEGMA)6 (poly(diaminopyridine acrylamide-co-2-(diisopropylamino)ethyl methacrylate-co-oligo(ethylene glycol) monomethyl ether methacrylate)6) is prepared, bearing hydrophilic and biocompatible POEGMA segment, along with hydrophobic PDAPA and PDPMA segments, characterizing the randomly dispersed dual functionalities, i.e., heterocomplementary H-bonding DAP motifs and pH-responsive protonation DPMA content. Thanks to the identical DAP/HCFU and DAP/TTPP H-bonding association capability, the incorporation of both HCFU and TTPP to six-arm star-shaped P(DAPA-co-DPMA-co-OEGMA)6 vehicle, with an optimized coloading ratio, can be straightforwardly realized by adjusting the feeding concentrations, thus yielding the hydrogen-bonded supramolecular nanoparticles (i.e., HCFU-TTPP-SPNs), demonstrating the codelivery of two components with the promise to optimize the combined CT/PDT efficacy.

Ultrasound-propelled nanomotors for efficient cancer cell ferroptosis

Ferroptosis is a non-apoptotic form of cell death that is dependent on the accumulation of intracellular iron that causes elevation of toxic lipid peroxides. Therefore, it is crucial to improve the levels of intracellular iron and reactive oxygen species (ROS) in a short time. Here, we first propose ultrasound (US)-propelled Janus nanomotors (Au-FeOx/PEI/ICG, AFPI NMs) to accelerate cellular internalization and induce cancer cell ferroptosis. This nanomotor consists of a gold-iron oxide rod-like Janus nanomotor (Au-FeOx, AF NMs) and a photoactive indocyanine green (ICG) dye on the surface. It not only exhibits accelerating cellular internalization (∼4-fold) caused by its attractive US-driven propulsion but also shows good intracellular motion behavior. In addition, this Janus nanomotor shows excellent intracellular ROS generation performance due to the synergistic effect of the "Fenton or Fenton-like reaction" and the "photochemical reaction". As a result, the killing efficiency of actively moving nanomotors on cancer cells is 88% higher than that of stationary nanomotors. Unlike previous passive strategies, this work is a significant step toward accelerating cellular internalization and inducing cancer-cell ferroptosis in an active way. These novel US-propelled Janus nanomotors with strong propulsion, efficient cellular internalization and excellent ROS generation are suitable as a novel cell biology research tool.

Hypoxia-Responsive Polymeric Nanoprodrugs for Combo Photodynamic and Chemotherapy

Hypoxia in most solid tumors is a major challenge for photodynamic therapy (PDT), and the combination of hypoxia-activated chemotherapy and PDT is a promising approach for enhanced anticancer activity. Herein, we designed hypoxia-responsive polymeric nanoprodrug PNPs to co-deliver photosensitizer 5,10,5,20-tetrakis(4-aminophenyl)-porphine (TAPP) and chlorambucil (CB) to improve the overall therapeutic efficacy. Upon laser irradiation, the central TAPP converted oxygen to produce single oxygen (1O2) for PDT and induced PDT-reduced hypoxia environment, which accelerated the release of activated CB for synergetic cancer cell killing. Consequently, these hypoxia-responsive polymeric nanoprodrugs with a considerable drug-loading content and synergistic therapeutic effect of PDT-CT had great potential for tumor therapy.

Molecularly Engineered Room-Temperature Phosphorescence for Biomedical Application: From the Visible toward Second Near-Infrared Window

Phosphorescence, characterized by luminescent lifetimes significantly longer than that of biological autofluorescence under ambient environment, is of great value for biomedical applications. Academic evidence of fluorescence imaging indicates that virtually all imaging metrics (sensitivity, resolution, and penetration depths) are improved when progressing into longer wavelength regions, especially the recently reported second near-infrared (NIR-II, 1000-1700 nm) window. Although the emission wavelength of probes does matter, it is not clear whether the guideline of "the longer the wavelength, the better the imaging effect" is still suitable for developing phosphorescent probes. For tissue-specific bioimaging, long-lived probes, even if they emit visible phosphorescence, enable accurate visualization of large deep tissues. For studies dealing with bioimaging of tiny biological architectures or dynamic physiopathological activities, the prerequisite is rigorous planning of long-wavelength phosphorescence, being aware of the cooperative contribution of long wavelengths and long lifetimes for improving the spatiotemporal resolution, penetration depth, and sensitivity of bioimaging. In this Review, emerging molecular engineering methods of room-temperature phosphorescence are discussed through the lens of photophysical mechanisms. We highlight the roles of phosphorescence with emission from visible to NIR-II windows toward bioapplications. To appreciate such advances, challenges and prospects in rapidly growing studies of room-temperature phosphorescence are described.

Supramolecular Integration of Multifunctional Nanomaterial by Mannose-Decorated Azocalixarene with Ginsenoside Rb1 for Synergistic Therapy of Rheumatoid Arthritis

The complexity and progressive nature of diseases require the exploitation of multifunctional materials. However, introducing a function inevitably increases the complexity of materials, which complicates preparation and decreases reproducibility. Herein, we report a supramolecular integration of multifunctional nanomaterials based on mannose-modified azocalix[4]arene (ManAC4A) and ginsenoside Rb1 (Rb1), which showed advances of simplicity and reproducibility. ManAC4A possesses reactive oxygen species (ROS) scavenging capacity and hypoxia-responsiveness, together with macrophage-targeting and induction functionality. Collectively, the Rb1@ManAC4A assembly simply prepared by two components is integrated with multifunction, including triple targeting (ELVIS targeting, macrophage-targeting, and hypoxia-targeted release) and triple therapy (ROS scavenging, macrophage polarization, and the anti-inflammatory effect of Rb1). The spontaneous assembly and recognition of ManAC4A, with its precise structure and molecular weight, facilitated the simple and straightforward preparation of Rb1@ManAC4A, leading to excellent batch consistency. Progress in simplicity and reproducibility, as directed by this research, will catalyze the clinical translation of multifunctional materials.

Multifunctional Nanoparticles for Enhanced Chemodynamic/Photodynamic Therapy through a Photothermal, H2O2-Elevation, and GSH-Consumption Strategy

Chemodynamic therapy (CDT) has witnessed significant advancements in recent years due to its specific properties. Its association with photodynamic therapy (PDT) has also garnered increased attention due to its mutually reinforcing effects. However, achieving further enhancement of the CDT/PDT efficacy remains a major challenge. In this study, we have developed an integrated nanosystem comprising a Fenton catalyst and multifunctional photosensitizers to achieve triply enhanced CDT/PDT through photothermal effects, H2O2 elevation, and GSH consumption. We prepared nano-ZIF-8 vesicles as carriers to encapsulate ferrocene-(phenylboronic acid pinacol ester) conjugates (Fc-BE) and photosensitizers IR825. Subsequently, cinnamaldehyde-modified hyaluronic acid (HA-CA) was coated onto ZIF-8 through metal coordination interactions, resulting in the formation of active targeting nanoparticles (NPs@Fc-BE&IR825). Upon cellular internalization mediated by CD44 receptors, HA-CA elevated H2O2 levels, while released Fc-BE consumed GSH and catalyzed H2O2 to generate highly cytotoxic hydroxyl radicals (·OH). Furthermore, NIR irradiation led to increased ·OH production and the generation of singlet oxygen (1O2), accompanied by a greater GSH consumption. This accelerated and strengthened amplification of oxidative stress can be harnessed to develop highly effective CDT/PDT nanoagents.

Water-soluble organic macrocycles based on dye chromophores and their applications

Traditional water-soluble organic macrocyclic receptors generally lack photofunctionality, thus monitoring the drug delivery and the phototheranostic applications of these host-guest macrocyclic systems has been greatly restricted. To address this issue, incorporating π-conjugated dye chromophores as building blocks into macrocyclic molecules is a straightforward and promising strategy. This approach not only imparts intrinsic optical features to the macrocycles themselves but also enhances the host-guest binding ability due to the large planar structures of the dyes. In this feature article, we focus on recent advances in water-soluble macrocyclic compounds based on organic dye chromophores, such as naphthalimide (NDI), perylene diimides (PDI), azobenzene (azo), tetraphenylethylene (TPE) and anthracene, and provide an overview of their various applications including molecular recognition, drug release, biological imaging, photothermal therapy, etc. We hope that this article could be helpful and instructive for the design of water-soluble dye-based macrocycles and the further development of their biomedical applications, particularly in combination with drug therapy and phototheranostics.

Polymersome Membrane Engineering with Active Targeting or Controlled Permeability for Responsive Drug Delivery

Polymersomes have been extensively investigated for drug delivery as nanocarriers for two decades due to a series of advantages including high stability under physiological conditions, simultaneous encapsulation of hydrophilic and hydrophobic drugs inside inner cavities and membranes, respectively, and facile adjustment of membrane and surface properties, as well as controlled drug release through incorporation of stimuli-responsive components. Despite these features, polymersome nanocarriers frequently suffer from nontargeting delivery and poor membrane permeability. In recent years, polymersomes have been functionalized for more efficient drug delivery. The surface shells were explored to be modified with diverse active targeting groups to improve disease-targeting delivery. The membrane permeability of the polymersomes was adjusted by incorporation of the stimuli-responsive components for smart controlled transportation of the encapsulated drugs. Therefore, being the polymersome-biointerface, tailorable properties can be introduced by its carefully modulated engineering. This review elaborates on the role of polymersome membranes as a platform to incorporate versatile features. First, we discuss how surface functionalization facilitates the directional journey to the targeting sites toward specific diseases, cells, or intracellular organelles via active targeting. Moreover, recent advances in the past decade related to membrane permeability to control drug release are also summarized. We finally discuss future development to promote polymersomes as in vivo drug delivery nanocarriers.

A general supramolecular adjuvant for pesticides based on host-guest recognition

BACKGROUND

Pesticides are indispensable in agriculture and can effectively improve the yields and quality of crops. Due to their weak water solubility, most pesticides need to be dissolved by adding solubilizing adjuvants. In this work, based on molecular recognition of the macrocyclic host, we developed a novel supramolecular adjuvant, called sulfonated azocalix[4]arene (SAC4A), which significantly improves the water solubility of pesticides.

RESULTS

SAC4A presents multiple advantages, including high water solubility, strong binding affinity, universality, and simple preparation. SAC4A showed an average binding constant value of 1.66 × 105  M-1 for 25 pesticides. Phase solubility results indicated that SAC4A increased the water solubility of pesticides by 80-1310 times. The herbicidal, fungicidal, and insecticidal activities of supramolecular formulations were found to be superior to those of technical pesticides, and the herbicidal effects were even better than those of commercial formulations.

CONCLUSION

Overall results revealed the potential of SAC4A to improve the solubility and effectiveness of pesticides, providing a new development idea for the application of adjuvants in agriculture. © 2023 Society of Chemical Industry.

Self-assembled nanoformulations of paclitaxel for enhanced cancer theranostics

Chemotherapy has occupied the critical position in cancer therapy, especially towards the post-operative, advanced, recurrent, and metastatic tumors. Paclitaxel (PTX)-based formulations have been widely used in clinical practice, while the therapeutic effect is far from satisfied due to off-target toxicity and drug resistance. The caseless multi-components make the preparation technology complicated and aggravate the concerns with the excipients-associated toxicity. The self-assembled PTX nanoparticles possess a high drug content and could incorporate various functional molecules for enhancing the therapeutic index. In this work, we summarize the self-assembly strategy for diverse nanodrugs of PTX. Then, the advancement of nanodrugs for tumor therapy, especially emphasis on mono-chemotherapy, combinational therapy, and theranostics, have been outlined. Finally, the challenges and potential improvements have been briefly spotlighted.

Platelet-mimicking supramolecular nanomedicine with precisely integrated prodrugs for cascade amplification of synergistic chemotherapy

Camptothecin (CPT) and cisplatin (Pt) have shown synergistic effects on a variety of cancers during preclinical and clinical studies. However, the ratio of the two drugs often could not be precisely regulated in different delivery systems, which hinders the desired synergistic effect. In addition, the low delivery efficiency of the two drugs to the tumor further impedes the ideal therapeutic outcomes. Herein, we report that a platelet-mimicking supramolecular nanomedicine (SN) could precisely control of the ratio of CPT and Pt with a high tumor accumulation rate for cascade amplification of synergistic chemotherapy. The SN was fabricated via the host-guest interaction between cucurbit[7]uril conjugated hyaluronic acid (HA-CB[7]) and adamantane (ADA) respectively functionalized CPT- and Pt-based prodrugs. The ratio of CPT and Pt in the SN could be facilely regulated by simply controlling the loading ratio, based on the strong binding affinity between CB[7] and ADA, and SN60 with 60% CPT and 40% Pt showed the highest synergistic effects on 4T1 cells. To improve the tumor accumulation efficiency of SN, 5,6-dimethylxanthenone-4-acetic acid (DMXAA, a tumor vasculature-disruptive agent) was loaded into the optimized SN and then coated with platelet membrane to yield platelet-mimicking supramolecular nanomedicine (D@SN-P). D@SN-P could first passively accumulate in tumors owing to the enhanced permeability and retention (EPR) effect after intravenous administration. The initially release of DMXAA from D@SN-P could induce tumor vascular disruption, and the resultant epithelial collagen exposure around the disrupted tumor vasculature provided a target for further recruitment of platelet-mimicking SN, leading to cascade amplification of tumor accumulation with synergistic chemotherapy. Hence, this platelet-mimicking supramolecular nanomedicine presents a universal supramolecular strategy to finely regulate the ratio of loaded pro-drugs, and improve the accumulation efficiency to amplify chemotherapy via platelet-mimics.

Cucurbit[8]uril-based water-dispersible assemblies with enhanced optoacoustic performance for multispectral optoacoustic imaging

Organic small-molecule contrast agents have attracted considerable attention in the field of multispectral optoacoustic imaging, but their weak optoacoustic performance resulted from relatively low extinction coefficient and poor water solubility restrains their widespread applications. Herein, we address these limitations by constructing supramolecular assemblies based on cucurbit[8]uril (CB[8]). Two dixanthene-based chromophores (DXP and DXBTZ) are synthesized as the model guest compounds, and then included in CB[8] to prepare host-guest complexes. The obtained DXP-CB[8] and DXBTZ-CB[8] display red-shifted and increased absorption as well as decreased fluorescence, thereby leading to a substantial enhancement in optoacoustic performance. Biological application potential of DXBTZ-CB[8] is investigated after co-assembly with chondroitin sulfate A (CSA). Benefiting from the excellent optoacoustic property of DXBTZ-CB[8] and the CD44-targeting feature of CSA, the formulated DXBTZ-CB[8]/CSA can effectively detect and diagnose subcutaneous tumors, orthotopic bladder tumors, lymphatic metastasis of tumors and ischemia/reperfusion-induced acute kidney injury in mouse models with multispectral optoacoustic imaging.

Fluorophore-based host-guest assembly complexes for imaging and therapy

Recently, supramolecular chemistry with its unique properties has received considerable attention in many fields. Supramolecular fluorescent systems constructed on the basis of macrocyclic hosts are not only effective in overcoming the limitations of imaging and diagnostic reagents, but also in enhancing their performances. This paper summarizes the recent advances in supramolecular fluorescent systems based on host-guest interactions and their application in bioimaging and therapy as well as the challenges and prospects in developing novel supramolecular fluorescent systems.

Hyaluronic Acid-based Supramolecular Nanomedicine with Optimized Ratio of Oxaliplatin/Chlorin e6 for Combined Chemotherapy and O2-Economized Photodynamic Therapy

Dual- or multi-modality combination therapy has become one of the most effective strategies to overcome drug resistance in cancer therapy, and the optimized ratio of the therapeutic agents working on the tumor greatly affects the therapeutic outcomes. However, the absence of a facile method to optimize the ratio of therapeutic agents in nanomedicine has, at least in part, impaired the clinical potential of combination therapy. Herein, a new cucurbit[7]uril (CB[7])-conjugated hyaluronic acid (HA) based nanomedicine was developed, in which both chlorin e6 (Ce6) and oxaliplatin (OX) were co-loaded non-covalently at an optimized ratio via facile host-guest complexation, for optimal, combined photodynamic therapy (PDT)/chemotherapy. To maximize the therapeutic efficacy, a mitochondrial respiration inhibitor, atovaquone (Ato), was also loaded into the nanomedicine to limit consumption of oxygen by the solid tumor, sparing oxygen for more efficient PDT. Additionally, HA on the surface of nanomedicine allowed targeted delivery to cancer cells with over-expressed CD44 receptors (such as CT26 cell lines). Thus, this supramolecular nanomedicine platform with an optimal ratio of photosensitizer and chemotherapeutic agent not only provides an important new tool for enhanced PDT/chemotherapy of solid tumors, but also offers a CB[7]-based host-guest complexation strategy to facilely optimize the ratio of therapeutic agents for multi-modality nanomedicine. STATEMENT OF SIGNIFICANCE: Chemotherapy remains the most common modality for cancer treatment in clinical practice. Combination therapy by co-delivery of two or more therapeutic agents has been recognized as one of the most effective strategies to improve therapeutic outcome of cancer treatment. However, the ratio of loaded drugs could not be facilely optimized, which may greatly affect the combination efficiency and overall therapeutic outcome. Herein, we developed a hyaluronic acid based supramolecular nanomedicine with facile method to optimize the ratio of two therapeutic agents for improved therapeutic outcome. This supramolecular nanomedicine not only provides an important new tool for enhanced photodynamic therapy/chemotherapy of solid tumors, but also offers insights in using macrocyclic molecule-based host-guest complexation to facilely optimize the ratio of therapeutic agents in multi-modality nanomedicine.

Investigation into the Photochemical Properties of Methylene Blue-Immobilized Hydroxyapatite Nanoparticles for Theranostic Application

In the biomedical field, there has been a requirement for developing theranostic nanomaterials with higher biosafety, leading to both diagnosis and therapy. Methylene blue (MB⁺) is an organic dye with both photoluminescence (PL) and photosensitization abilities to generate singlet oxygen (¹O₂). However, MB⁺ easily loses its generation ability by hydrogen reduction in vivo or by forming aggregates. In this study, MB⁺ immobilized on biocompatible hydroxyapatite (HA) nanoparticles was applied for the bifunctions of efficient PL and photosensitization. The MB⁺-immobilized HA nanoparticles (MH) formed aggregates with sizes of 80-100 nm in phosphate buffer (PB). The generation amount and efficiency of ¹O₂ from the nanoparticles in PB seem to depend on the immobilized MB⁺ amount and the percentage of the monomer, respectively. Considering the larger immobilized amount and percentage of the MB⁺ monomer, it was found that there was MH with the lower generation amount and efficiency of ¹O₂ to exhibit the highest PL intensity. The photofunctional measurement of MB⁺ revealed the state of MB⁺ molecules on the HA surface, and it was suggested that the MB⁺ molecules immobilized on the MH surface would form more hydrogen bonds to change their excitation states. In the cellular experiments, the Hela cancer cells reacted with the nanoparticles and showed red-color PL, indicating cellular imaging. Furthermore, the adherent cell coverage decreased by ¹O₂ generation, indicating the importance of the immobilization amount of the MB⁺ monomer. Therefore, theranostic nanomaterials with biosafety were successfully synthesized to show two photofunctions, which provide both cellular imaging and photodynamic therapy by the nanohybrid system between HA and MB⁺.

Combinatorial Polydopamine-Liposome Nanoformulation as an Effective Anti-Breast Cancer Therapy

Introduction

Drug delivery systems (DDSs) based on liposomes are potential tools to minimize the side effects and substantially enhance the therapeutic efficacy of chemotherapy. However, it is challenging to achieve biosafe, accurate, and efficient cancer therapy of liposomes with single function or single mechanism. To solve this problem, we designed a multifunctional and multimechanism nanoplatform based on polydopamine (PDA)-coated liposomes for accurate and efficient combinatorial cancer therapy of chemotherapy and laser-induced PDT/PTT.

Methods

ICG and DOX were co-incorporated in polyethylene glycol modified liposomes, which were further coated with PDA by a facile two-step method to construct PDA-liposome nanoparticles (PDA@Lipo/DOX/ICG). The safety of nanocarriers was investigated on normal HEK-293 cells, and the cellular uptake, intracellular ROS production capacity, and combinatorial treatment effect of the nanoparticles were assessed on human breast cancer cells MDA-MB-231. In vivo biodistribution, thermal imaging, biosafety assessment, and combination therapy effects were estimated based on MDA-MB-231 subcutaneous tumor model.

Results

Compared with DOX·HCl and Lipo/DOX/ICG, PDA@Lipo/DOX/ICG showed higher toxicity on MDA-MB-231 cells. After endocytosis by target cells, PDA@Lipo/DOX/ICG produced a large amount of ROS for PDT by 808 nm laser irradiation, and the cell inhibition rate of combination therapy reached up to 80.4%. After the tail vein injection (DOX equivalent of 2.5 mg/kg) in mice bearing MDA-MB-231 tumors, PDA@Lipo/DOX/ICG significantly accumulated at the tumor site at 24 h post injection. After 808 nm laser irradiation (1.0 W/cm², 2 min) at this timepoint, PDA@Lipo/DOX/ICG efficiently suppressed the proliferation of MDA-MB-231 cell and even thoroughly ablated tumors. Negligible cardiotoxicity and no treatment-induced side effects were observed.

Conclusion

PDA@Lipo/DOX/ICG is a multifunctional nanoplatform based on PDA-coated liposomes for accurate and efficient combinatorial cancer therapy of chemotherapy and laser-induced PDT/PTT.

Development of stimuli responsive polymeric nanomedicines modulating tumor microenvironment for improved cancer therapy

The complexity of the tumor microenvironment (TME) severely hinders the therapeutic effects of various cancer treatment modalities. The TME differs from normal tissues owing to the presence of hypoxia, low pH, and immune-suppressive characteristics. Modulation of the TME to reverse tumor growth equilibrium is considered an effective way to treat tumors. Recently, polymeric nanomedicines have been widely used in cancer therapy, because their synthesis can be controlled and they are highly modifiable, and have demonstrated great potential to remodel the TME. In this review, we outline the application of various stimuli responsive polymeric nanomedicines to modulate the TME, aiming to provide insights for the design of the next generation of polymeric nanomedicines and promote the development of polymeric nanomedicines for cancer therapy.

Synergistically Enhancing Tumor Chemotherapy Using an Aggregation-Induced Emission Photosensitizer on Covalently Conjugated Molecularly Imprinted Polymer Nanoparticles

Due to the polygenic and heterogeneous nature of the tumorigenesis process, traditional chemotherapy is far from desirable. Fabricating multifunctional nanoplatforms integrating photodynamic effect can synergistically enhance chemotherapy because they can make the cancer cells much sensitive to chemotherapeutics. However, how to assemble different units in nanoplatforms and minimize side effects caused by chemodrugs and photosensitizers (PSs) still needs to be explored. Herein, a nanoplatform CPP/PS-MIP@DOX is developed using a simultaneously covalently conjugated new aggregation-induced emission (AIE) PS and a cell-penetrating peptide (CPP) on the surface of silica-based molecularly imprinted polymer (MIP) nanoparticles, prepared with doxorubicin (DOX) as the template in the water system via a sol-gel technique. CPP/PS-MIP@DOX has good biocompatibility, high DOX-loading ability, promoted cellular uptake, and sustained and pH-sensitive drug release capability. Furthermore, it can efficiently penetrate into tumor tissue, accurately home to, and accumulate at the tumor site. As a result, a better efficacy with lower cytotoxicity is achieved with a smaller dosage of DOX by utilizing either the photodynamic effect or unique characteristics of the MIP. It is the first nanoplatform fabricated by chemically conjugating AIE PSs directly on the surface of the scaffold via the surface-decorated strategy and successfully applied in cancer therapy. This work provides an effective strategy by constructing AIE PS-based cancer nanomedicines with MIPs as scaffolds.

Nanoparticles-based phototherapy systems for cancer treatment: Current status and clinical potential

Remarkable progress in phototherapy has been made in recent decades, due to its non-invasiveness and instant therapeutic efficacy. In addition, with the rapid development of nanoscience and nanotechnology, phototherapy systems based on nanoparticles or nanocomposites also evolved as an emerging hotspot in nanomedicine research, especially in cancer. In this review, first we briefly introduce the history of phototherapy, and the mechanisms of phototherapy in cancer treatment. Then, we summarize the representative development over the past three to five years in nanoparticle-based phototherapy and highlight the design of the innovative nanoparticles thereof. Finally, we discuss the feasibility and the potential of the nanoparticle-based phototherapy systems in clinical anticancer therapeutic applications, aiming to predict future research directions in this field. Our review is a tutorial work, aiming at providing useful insights to researchers in the field of nanotechnology, nanoscience and cancer.

Mechanoresponsive Drug Loading System with Tunable Host-Guest Interactions for Ocular Disease Treatment

Conventional administration of eye drops often requires high dosages and/or repetitive treatments to achieve therapeutic efficacy. This is inefficient and may result in side effects or even toxicity. Although many delivery systems of ophthalmic drugs have been reported, most of them work in a fixed format in which both the type and dose of the loaded drugs cannot be changed upon demand. To overcome this limitation, a hybrid double network hydrogel system composed of methacryloyl gelatin, pluronic F127 diacrylate, and β-cyclodextrin-modified oxidized dextran was developed. The hydrogels presented good mechanical strength and biocompatibility. In vitro assessments demonstrated that the hydrogels loaded with commonly used ophthalmic drugs could sustain the drug release for more than 21 days. This hydrogel system exhibited features of mechanoresponsive drug loading, and the capacity of drug loading could be significantly enhanced by macroscopically mechanical compression. Further in vivo evaluation of the drug delivery capacity showed that a dexamethasone-loaded hydrogel as a fornix insert effectively suppressed upregulation of proangiogenic factors and suture-induced corneal neovascularization in rats. This novel hydrogel system represents a promising drug delivery platform, which could potentially improve the treatments of ocular surface and other diseases.

Emerging Strategies in Stimuli-Responsive Prodrug Nanosystems for Cancer Therapy

Prodrugs are chemically modified drug molecules that are inactive before administration. After administration, they are converted in situ to parent drugs and induce the mechanism of action. The development of prodrugs has upgraded conventional drug treatments in terms of bioavailability, targeting, and reduced side effects. Especially in cancer therapy, the application of prodrugs has achieved substantial therapeutic effects. From serendipitous discovery in the early stage to functional design with pertinence nowadays, the importance of prodrugs in drug design is self-evident. At present, studying stimuli-responsive activation mechanisms, regulating the stimuli intensity in vivo, and designing nanoscale prodrug formulations are the major strategies to promote the development of prodrugs. In this review, we provide an outlook of recent cutting-edge studies on stimuli-responsive prodrug nanosystems from these three aspects. We also discuss prospects and challenges in the future development of such prodrugs.

A smart nanoplatform for enhanced photo-ferrotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Emerging therapies, such as ferroptosis mediated cancer therapy and phototherapy, offer new opportunities for HCC treatment. The combination of multiple treatments is often more effective than monotherapy, but many of the current treatments are prone to serious side effects, resulting in a serious decline in patients’ quality of life. Therefore, the combination therapy of tumor in situ controllable activation will improve the efficacy and reduce side effects for precise treatment of tumor. Herein, we synthesized a GSH-activatable nanomedicine to synergize photothermal therapy (PTT) and ferrotherapy. We utilized a near-infrared dye SQ890 as both an iron-chelating and a photothermal converter agent, which was encapsulated with a GSH-sensitive polymer (PLGA-SS-mPEG), to attain the biocompatible SQ890@Fe nanoparticles (NPs). In the tumor microenvironment (TME), SQ890@Fe NPs showed a GSH-activated photothermal effect that could increase the Fenton reaction rate. Meanwhile, the depletion of GSH could further increase ferroptosis effect. In turn, the increasing radical generated by ferrotherapy could impair the formation of heat shock proteins (HSPs) which could amplify PTT effects by limiting the self-protection mechanism. Overall, the intelligent nanomedicine SQ890@Fe NPs combines ferrotherapy and PTT to enhance the efficacy and safety of cancer treatment through the mutual promotion of the two treatment mechanisms, providing a new dimension for tumor combination therapy.

Folic Acid-Modified Cyclodextrin Multivalent Supramolecular Assembly for Photodynamic Therapy

The construction of supramolecular multivalent assemblies with unique photoluminescence behaviors and biological functions has become a research hot spot recently in the biomaterial field. Herein, we report an adaptive supramolecular assembly via a multivalent co-assembly strategy prepared in two stages by using an adamantane-connected pyrenyl pyridinium derivative (APA2), sulfonated aluminum phthalocyanine (PcS), and folic acid-modified β-cyclodextrin (FA-CD) for efficient dual-organelle targeted photodynamic cancer cell ablation. Benefiting from π-π and electrostatic interactions, APA2 and PcS could first assemble into non-fluorescent irregular nanoaggregates because of the heterodimer aggregation-induced quenching and then secondarily assemble with FA-CD to afford targeted spherical nanoparticles (NPs) with an average diameter of around 50 nm, which could be specifically taken up by HeLa cancer cells through endocytosis in comparison with 293T normal cells. Intriguingly, such multivalent NPs could adaptively disaggregate in an intracellular physiological environment of cancer cells and further respectively and selectively accumulate in mitochondria and lysosomes, which not only displayed near-infrared two-organelle localization in situ but also aroused efficient singlet oxygen generation under light irradiation to effectively eliminate cancer cells up to 99%. This supramolecular multivalent assembly with an adaptive feature in a specific cancer cell environment provides a feasible strategy for precise organelle-targeted imaging and an efficiently synergetic photodynamic effect in situ for cancer cell ablation.

Laser-responsive multi-functional nanoparticles for efficient combinational chemo-photodynamic therapy against breast cancer

Herein, novel laser-responsive multi-functional nanoparticles (NPs-Lip@PTX/CyA/Ce6) were fabricated with bovine serum albumins (BSA) based nanoparticles, which simultaneously carried chemotherapeutic drug paclitaxel (PTX) and P-gp inhibitor cyclosporin A (CyA), as core and photosensitizer agent Chlorin e6 (Ce6) loaded Tf-modified liposomal bilayer as shell. NPs-Lip@PTX/CyA/Ce6 exhibited apparent core-shell structure morphology with particle size of 160.9 ± 1.7 nm and zeta potential of - 26.7 ± 0.6 mV, indicating their excellent stability in aqueous solution. Besides, NPs-Lip@PTX/CyA/Ce6 possessed laser-responsive release profiles upon laser irradiation at specific wavelength, which was favor to exert efficient combinatorial chemo-photodynamic therapy and effectively reverse the multiple drug resistance (MDR). Under laser irradiation, as expected, NPs-Lip@PTX/CyA/Ce6 demonstrated superb intracellular ROS productivity and fantastic in vitro and in vivo anti-cancer therapy effect but absent of systemic toxicity. In conclusion, the nano-drug delivery system would be prospectively applied in clinic as resultful therapeutic tactic for investing compositional chemo-photodynamic therapy synergistically.

Research Progress of Conjugated Nanomedicine for Cancer Treatment

The conventional cancer therapeutic modalities include surgery, chemotherapy and radiotherapy. Although immunotherapy and targeted therapy are also widely used in cancer treatment, chemotherapy remains the cornerstone of tumor treatment. With the rapid development of nanotechnology, nanomedicine is believed to be an emerging field to further improve the efficacy of chemotherapy. Until now, there are more than 17 kinds of nanomedicine for cancer therapy approved globally. Thereinto, conjugated nanomedicine, as an important type of nanomedicine, can not only possess the targeted delivery of chemotherapeutics with great precision but also achieve controlled drug release to avoid adverse effects. Meanwhile, conjugated nanomedicine provides the platform for combining several different therapeutic approaches (chemotherapy, photothermal therapy, photodynamic therapy, thermodynamic therapy, immunotherapy, etc.) with the purpose of achieving synergistic effects during cancer treatment. Therefore, this review focuses on conjugated nanomedicine and its various applications in synergistic chemotherapy. Additionally, the further perspectives and challenges of the conjugated nanomedicine are also addressed, which clarifies the design direction of a new generation of conjugated nanomedicine and facilitates the translation of them from the bench to the bedside.

Highly water-dispersible PCN nanosheets as light-controlled lysosome self-promoting escape type non-cationic gene carriers for tumor therapy

The construction of non-viral gene delivery faces two major challenges: cytotoxicity caused by high cationic charge units and easy degradation by lysosomes. Herein, highly water-dispersible polymeric carbon nitride (PCN) nanosheets were utilized as the core to construct a light-controlled non-cationic gene delivery system with sufficient lysosomal escape ability. In this system, these nanosheets exhibited efficient DNA condensation, outstanding biocompatibility, transfection tracking, light responsiveness and high transfection efficiency. Once PCN-DNA was taken up by the tumor cells, the accumulated ROS generated by photosensitizers (PSs) under light irradiation would destroy the structure of lysosomes, promote the escape of PCN-DNA and increase the efficiency of gene transfection. Simultaneously, the gene transfection process could be tracked in real time through fluorescence imaging technology, which was conducive to investigate the transfection mechanism. In vitro and in vivo experiments further confirmed that PCN nanosheets loaded with the P53 gene were beneficial to the regeneration of the P53 apoptotic pathway, increased tumor sensitivity to PSs, and further induced tumor cell apoptosis. In summary, the highly water-dispersible PCN nanosheets were applied to light-controlled self-escaping gene delivery for the first time, and tumor gene therapy was successfully realized.

A Hybrid Supramolecular Polymeric Nanomedicine for Cascade-Amplified Synergetic Cancer Therapy

Supramolecular nanomedicines have shown great merits in cancer therapy, but their clinical translation is hampered by monotonous therapeutic modality and unsatisfactory antitumor performance. Herein, a hybrid supramolecular polymeric nanomedicine (SNPs) is developed based on β-cyclodextrin/camptothecin (CPT) host-guest molecular recognition and iron-carboxylate coordination. Iron ions stabilizing SNPs catalyze the conversion of intracellular hydrogen peroxide into highly toxic hydroxyl radical through a Fenton reaction, which further cleaves the thioketal linker of the supramolecular monomer to release potent CPT, thus amplifying the therapeutic efficacy by combining chemodynamic therapy and chemotherapy. The combination therapy stimulates antitumor immunity and promotes intratumoral infiltration of cytotoxic T lymphocytes by triggering immunogenic cell death. In synergy with PD-L1 checkpoint blockade, SNPs enables enhanced immune therapy and a long-term tumor remission.

On-Demand Generation of Peroxynitrite from an Integrated Two-Dimensional System for Enhanced Tumor Therapy

Nanosystem-mediated tumor radiosensitization strategy combining the features of X-ray with infinite penetration depth and high atomic number elements shows considerable application potential in clinical cancer therapy. However, it is difficult to achieve satisfactory anticancer efficacy using clinical radiotherapy for the majority of solid tumors due to the restrictions brought about by the tumor hypoxia, insufficient DNA damage, and rapid DNA repair during and after treatment. Inspired by the complementary advantages of nitric oxide (NO) and X-ray-induced photodynamic therapy, we herein report a two-dimensional nanoplatform by the integration of the NO donor-modified LiYF₄:Ce scintillator and graphitic carbon nitride nanosheets for on-demand generation of highly cytotoxic peroxynitrite (ONOO^-). By simply adjusting the Ce³⁺ doping content, the obtained nanoscintillator can realize high radioluminescence, activating photosensitive materials to simultaneously generate NO and superoxide radical for the formation of ONOO^- in the tumor. Obtained ONOO^- effectively amplifies therapeutic efficacy of radiotherapy by directly inducing mitochondrial and DNA damage, overcoming hypoxia-associated radiation resistance. The level of glutamine synthetase (GS) is downregulated by ONOO^-, and the inhibition of GS delays DNA damage repair, further enhancing radiosensitivity. This work establishes a combinatorial strategy of ONOO^- to overcome the major limitations of radiotherapy and provides insightful guidance to clinical radiotherapy.

Chemiexcitation-Triggered Prodrug Activation for Targeted Carbon Monoxide Delivery

Photolysis-based prodrug strategy can address some critical drug delivery issues, which otherwise are very challenging to tackle with traditional prodrug strategy. However, the need for external light irradiation significantly hampers its in vivo application due to the poor light accessibility of deep tissue. Herein, we propose a new strategy of chemiexcitation-triggered prodrug activation, wherein a photoresponsive prodrug is excited for drug payload release by chemiexcitation instead of photoirradiation. As such, the bond-cleavage power of photolysis can be employed to address some critical drug delivery issues while obviating the need for external light irradiation. We have established the proof of concept by the successful development of a chemiexcitation responsive carbon monoxide delivery platform, which exhibited specific CO release at the tumor site and pronounced tumor suppression effects. We anticipate that such a concept of chemiexcitation-triggered prodrug activation can be leveraged for the targeted delivery of other small molecule-based drug payloads.

Self-boosting stimulus activation of a polyprodrug with cascade amplification for enhanced antitumor efficacy

The use of polyprodrugs, which bind drugs to polymer chains through responsive linkers, is a potential technique for cancer therapy; however, a lack of endogenous triggering factors limits drug activation in tumor tissue. Herein, we rationally created a reactive oxygen species (ROS)-sensitive polyprodrug (TS_CA/DOX) with cascade amplification of triggering agents and drug activation by incorporating both an ROS signal amplifier (TA_CA) and a drug activation amplifier (SIP_DOX) into a delivery system. Endogenous ROS as a triggering mechanism kicked off the initial circulation phase to increase intracellular ROS signals. Subsequently, the enhanced ROS initiated the second degradation step, allowing the polyprodrug SIP_DOX to fracture spontaneously in a domino-like fashion, resulting in self-accelerated drug activation in tumor tissue. Therefore, the polyprodrug created in this study with cascade amplification of drug activation holds great promise for effective cancer treatment.

In Vitro Therapeutic Attributes of Luminescent Hydroxyapatite Nanoparticles in Codelivery Module

Imminent prospects of clinical importance have been accomplished through divergent treatment modalities implemented using nanoscale platforms. In the present study, hydroxyapatite nanoparticles doped with copper nanoclusters (HAPs) were explored for codelivery of a hydrophobic drug, namely, norfloxacin (NX), and a hydrophilic photosensitizer, such as methylene blue (MB). NX and MB were successfully homed into HAPs (MB-NX-HAPs), which further exhibited a pH-dependent release of both. With the objective of attaining an enhanced effect, MB-NX-HAPs were evaluated for combination therapy, involving chemotherapy and photodynamic therapy (PDT) with irradiation at 640 nm. The combinatorial therapy approach was initially applied for antibacterial therapy, which suggested a considerable reduction in bacterial growth of Gram-negative strain Pseudomonas aeruginosa MTCC 2488. Thereafter, the antiproliferative study performed in cancer cell lines (HeLa and MCF-7) revealed the efficiency of MB-NX-HAPs in bestowing a combinatorial effect through chemotherapy and PDT (irradiation at 640 nm). The combined effect exerted through MB-NX-HAPs subsequently induced reactive oxygen species (ROS) generation, cell cycle alteration, and apoptosis activation in cancer cells. The biocompatible nature of MB-NX-HAPs was appreciably shown through their minimal effect on the normal cell line (HEK-293). Additionally, HAPs through luminescence of copper nanoclusters were suggested to aid in bioimaging of cancer cell lines.

Self-assembled Pt(II) metallacycles enable precise cancer combination chemotherapy

Coadministration of drug molecules in adequate combinations for cancer treatment reduces the doses of each constituent, overcomes resistance mechanisms, and reduces the influence of tumor heterogeneity. Here we utilize coordination-driven self-assembly to prepare platinum(II) metallacycles comprising two drug molecules with distinct anticancer mechanisms in precise ratios. Nanoformulations fabricated by encapsulating the metallacycles into amphiphilic diblock copolymers efficiently enter cancer cells and release the active drug molecules at the exact loading ratio in the reductive cancer microenvironments, leading to a synergistic anticancer effect and therefore a favorable treatment outcome. This study provides a promising supramolecular methodology for the precise organization and delivery of bioactive molecules for inducing synergistic biological effects that maximize therapeutic efficacy.

Combination chemotherapy, which involves the simultaneous use of multiple anticancer drugs in adequate combinations to disrupt multiple mechanisms associated with tumor growth, has shown advantages in enhanced therapeutic efficacy and lower systemic toxicity relative to monotherapy. Herein, we employed coordination-driven self-assembly to construct discrete Pt(II) metallacycles as monodisperse, modular platforms for combining camptothecin and combretastatin A4, two chemotherapy agents with a disparate mechanism of action, in precise arrangements for combination chemotherapy. Formulation of the drug-loaded metallacycles with folic acid–functionalized amphiphilic diblock copolymers furnished nanoparticles with good solubility and stability in physiological conditions. Folic acids on the surface of the nanoparticles promote their internalization into cancer cells. The intracellular reductive environment of cancer cells induces the release of the drug molecules at an exact 1:1 ratio, leading to a synergistic anticancer efficacy. In vivo studies on tumor-bearing mice demonstrated the favorable therapeutic outcome and minimal side effects of the combination chemotherapy approach based on a self-assembled metallacycle.

A Calixarene Assembly Strategy of Combined Anti-Neuroinflammation and Drug Delivery Functions for Traumatic Brain Injury Therapy

Excessive inflammatory reaction aggravates brain injury and hinders the recovery of neural function in nervous system diseases. Microglia, as the major players of neuroinflammation, control the progress of the disease. There is an urgent need for effective non-invasive therapy to treat neuroinflammation mediated by microglia. However, the lack of specificity of anti-inflammatory agents and insufficient drug dose penetrating into the brain lesion area are the main problems. Here, we evaluated a series of calixarenes and found that among them the self-assembling architecture of amphiphilic sulfonatocalix[8]arene (SC8A12C) had the most potent ability to suppress neuroinflammation in vitro and in vivo. Moreover, SC8A12C assemblies were internalized into microglia through macropinocytosis. In addition, after applying the SC8A12C assemblies to the exposed brain tissue, we observed that SC8A12C assemblies penetrated into the brain parenchyma and eliminated the inflammatory factor storm, thereby restoring neurobiological functions in a mouse model of traumatic brain injury.

Two-Dimensional Nanomaterial-based catalytic Medicine: Theories, advanced catalyst and system design

Two-dimensional nanomaterial-based catalytic medicines that associate the superiorities of novel catalytic mechanisms with nanotechnology have emerged as absorbing therapeutic strategies for cancer therapy. Catalytic medicines featuring high efficiency and selectivity have been widely used as effective anticancer strategies without applying traditional nonselective and highly toxic chemodrugs. Moreover, two-dimensional nanomaterials are characterized by distinctive physicochemical properties, such as a sizeable bandgap, good conductivity, fast electron transfer and photoelectrochemical activity. The introduction of two-dimensional nanomaterials into catalytic medicine provides a more effective, controllable, and precise antitumor strategy. In this review, different types of two-dimensional nanomaterial-based catalytic nanomedicines are generalized, and their catalytic theories, advanced catalytic pathways and catalytic nanosystem design are also discussed in detail. Notably, future challenges and obstacles in the design and further clinical transformation of two-dimensional nanomaterial-based catalytic nanomedicine are prospected.

Cyclodextrin-Activated Porphyrin Photosensitization for Boosting Self-Cleavable Drug Release

Supramolecular prodrugs that combine the merits of stimuli-responsiveness and targeting ability in a controllable manner have shown appealing prospects in disease diagnostics and therapeutics. Herein, we report that a new theranostic agent with the host-guest-binding-activated photosensitization has been fabricated by a binary supramolecular assembly consisting of the permethyl-β-cyclodextrin-grafted hyaluronic acid and a combretastatin A-4-appended porphyrin derivative. Illuminated by a red-light source, the production efficiency of singlet oxygen (¹O₂) pronouncedly increases by ∼60-fold once the porphyrin core is encapsulated by cyclodextrins. Consequently, the cell-selective fluorescence emission is dramatically enhanced, the microtubule-targeted drug is rapidly and completely released, and the ¹O₂-involved combinational treatment is simultaneously achieved both in vitro and in vivo. To be envisaged, this complexation-boosted light-activatable photosensitizing prodrug delivery system with improved photophysical performance and remarkable phototheranostic outcomes will make a significant contribution to the creation of more advanced stimulus-based biomaterials.

pH/ROS dual-responsive supramolecular polypeptide prodrug nanomedicine based on host-guest recognition for cancer therapy

Supramolecular nanomedicine assembly combined with polypeptide prodrug could become a powerful strategy to minimize drug leakage in blood circulation and trigger sufficient drug release at tumor tissue. Here, we developed a charge-reversal amphiphilic pillar[5]arene-modified polypeptide (P5-PLL-DMA), and reactive oxygen species (ROS)-sensitive polypeptide prodrug (P-PLL-DOX) including a ROS-cleavable thioketal (TK) linker between doxorubicin (DOX) and poly(_L-lysine) (PLL), which could assemble via pillar[5]arene host-guest recognition, and further encapsulate chlorin e6 (Ce6) to obtain a supramolecular polypeptide prodrug (SPP-DOX/Ce6). The chemical conjugation to load drugs of DOX and the negatively charge of SPP-DOX/Ce6 could prevent premature drug leakage, and reduce undesirable interaction with serum proteins to enhance stability under physiological conditions (pH 7.4). Simultaneously, the carried charge of SPP-DOX/Ce6 reversed from negative to positive could effectively enhance the cellular internalization for efficient DOX delivery under acidic tumor microenvironment (pH 6.5). Upon 660 nm near-infrared light (NIR) irradiation, the ROS generated by encapsulated Ce6 rapidly cleaved the TK linker to release activated DOX, inducing the tumor-specific drug delivery. This intelligent supramolecular polypeptide prodrug based on pillar[5]arene host-guest recognition represents new avenues to develop stimulus responsive prodrug for enhanced cancer therapy with minimized the side effect. STATEMENT OF SIGNIFICANCE: In this work, a pH/ROS dual-sensitive supramolecular polypeptide prodrug (SPP-DOX/Ce6) was developed to minimize drug leakage in blood circulation and trigger sufficient drug release at tumor tissue. The chemical conjugation to load drugs of DOX via a ROS-cleavable thioketal (TK) linker and the distinctive charge-reversal capacity of SPP-DOX/Ce6 significantly enhances the stability under physiological conditions (pH 7.4), while facilitates cellular uptake at tumor site (pH 6.8). Upon 660 nm near-infrared light (NIR) irradiation, the ROS generated by encapsulated Ce6 induces the rapid cleavage of TK linker to release activated DOX, achieving a tumor-specific drug delivery. This intelligent supramolecular polypeptide prodrug SPP-DOX/Ce6 provides an effective strategy to construct stimulus responsive prodrug for enhanced cancer therapy.

Stimulus-responsive self-assembled prodrugs in cancer therapy

Small-molecule prodrugs have become the main toolbox to improve the unfavorable physicochemical properties of potential therapeutic compounds in contemporary anti-cancer drug development. Many approved small-molecule prodrugs, however, still face key challenges in their pharmacokinetic (PK) and pharmacodynamic (PD) properties, thus severely restricting their further clinical applications. Self-assembled prodrugs thus emerged as they could take advantage of key benefits in both prodrug design and nanomedicine, so as to maximize drug loading, reduce premature leakage, and improve PK/PD parameters and targeting ability. Notably, temporally and spatially controlled release of drugs at cancerous sites could be achieved by encoding various activable linkers that are sensitive to chemical or biological stimuli in the tumor microenvironment (TME). In this review, we have comprehensively summarized the recent progress made in the development of single/multiple-stimulus-responsive self-assembled prodrugs for mono- and combinatorial therapy. A special focus was placed on various prodrug conjugation strategies (polymer-drug conjugates, drug-drug conjugates, etc.) that facilitated the engineering of self-assembled prodrugs, and various linker chemistries that enabled selective controlled release of active drugs at tumor sites. Furthermore, some polymeric nano-prodrugs that entered clinical trials have also been elaborated here. Finally, we have discussed the bottlenecks in the field of prodrug nanoassembly and offered potential solutions to overcome them. We believe that this review will provide a comprehensive reference for the rational design of effective prodrug nanoassemblies that have clinic translation potential.

Reactive Oxygen Species-Responsive Nanococktail With Self-Amplificated Drug Release for Efficient Co-Delivery of Paclitaxel/Cucurbitacin B and Synergistic Treatment of Gastric Cancer

Application of drug combinations is a powerful strategy for the therapy of advanced gastric cancer. However, the clinical use of such combinations is greatly limited by the occurrence of severe systemic toxicity. Although polymeric-prodrug-based nanococktails can significantly reduce toxicity of drugs, they have been shown to have low intracellular drug release. To balance between efficacy and safety during application of polymeric-prodrug-based nanococktails, a reactive oxygen species (ROS)-responsive nanococktail (PCM) with self-amplification drug release was developed in this study. In summary, PCM micelles were co-assembled from ROS-sensitive cucurbitacin B (CuB) and paclitaxel (PTX) polymeric prodrug, which were fabricated by covalently grafting PTX and CuB to dextran via an ROS-sensitive linkage. To minimize the side effects of the PCM micelles, a polymeric-prodrug strategy was employed to prevent premature leakage. Once it entered cancer cells, PCM released CuB and PTX in response to ROS. Moreover, the released CuB further promoted ROS generation, which in turn enhanced drug release for better therapeutic effects. In vivo antitumor experiments showed that the PCM-treated group had lower tumor burden (tumor weight was reduced by 92%), but bodyweight loss was not significant. These results indicate that the developed polymeric prodrug, with a self-amplification drug release nanococktail strategy, can be an effective and safe strategy for cancer management.

Light-Triggered Polymersome-Based Anticancer Therapeutics Delivery

Polymersomes are biomimetic cell membrane-like model structures that are self-assembled stepwise from amphiphilic copolymers. These polymeric (nano)carriers have gained the scientific community’s attention due to their biocompatibility, versatility, and higher stability than liposomes. Their tunable properties, such as composition, size, shape, and surface functional groups, extend encapsulation possibilities to either hydrophilic or hydrophobic cargoes (or both) and their site-specific delivery. Besides, polymersomes can disassemble in response to different stimuli, including light, for controlling the “on-demand” release of cargo that may also respond to light as photosensitizers and plasmonic nanostructures. Thus, polymersomes can be spatiotemporally stimulated by light of a wide wavelength range, whose exogenous response may activate light-stimulable moieties, enhance the drug efficacy, decrease side effects, and, thus, be broadly employed in photoinduced therapy. This review describes current light-responsive polymersomes evaluated for anticancer therapy. It includes light-activable moieties’ features and polymersomes’ composition and release behavior, focusing on recent advances and applications in cancer therapy, current trends, and photosensitive polymersomes’ perspectives.