Carrier-Free Hybrid DNA Nanoparticles for Light-Induced Self-Delivery of Functional Nucleic Acid Enzymes

Efficient delivery of curcumin by functional solid lipid nanoparticles with promoting endosomal escape and liver targeting properties

In the realm of intracellular drug delivery, overcoming the barrier of endosomal entrapment stands as a critical factor influencing the effectiveness of nanodrug delivery systems. This study focuses on the synthesis of an acid-sensitive fatty acid derivative called imidazole-stearic acid (IM-SA). Leveraging the proton sponge effect attributed to imidazole groups, IM-SA was anticipated to play a pivotal role in facilitating endosomal escape. Integrated into the lipid core of solid lipid nanoparticles (SLNs), IM-SA was paired with hyaluronic acid (HA) coating on the surface of SLNs loading with curcumin (CUR). The presence of IM-SA and HA endowed HA-IM-SLNs@CUR with dual functionalities, enabling the promotion of endosomal escape, and specifical targeting of liver cancer. HA-IM-SLNs@CUR exhibited a particle size of ∼228 nm, with impressive encapsulation efficiencies (EE) of 87.5 % ± 2.3 % for CUR. Drugs exhibit significant pH sensitive release behavior. Cellular experiments showed that HA-IM-SLN@CUR exhibits enhanced drug delivery capability. The incorporation of IM-SA significantly improved the endosomal escape of HA-IM-SLN@CUR, facilitating accelerated intracellular drug release and increasing intracellular drug concentration, exhibiting excellent growth inhibitory effects on HepG2 cells. Animal experiments revealed a 3.4-fold increase in CUR uptake at the tumor site with HA-IM-SLNs@CUR over the free CUR, demonstrating remarkable tumor homing potential with the tumor growth inhibition rate of 97.2 %. These findings indicated the significant promise of HA-IM-SLNs@CUR in the realm of cancer drug delivery.

Novel targeting liposomes with enhanced endosomal escape for co-delivery of doxorubicin and curcumin

Effective endosomal escape is crucial for enhancing the efficiency of nanodrug delivery systems. In this study, we developed a novel liposomal system utilizing acid-sensitive N-(3-amino-propyl) imidazole cholesterol (IM-Chol), specifically designed for the targeted co-delivery of doxorubicin (DOX) and curcumin (CUR) to hepatocellular carcinoma (HCC). Designated as GA-IM-LIP@DOX/CUR, this liposomal system incorporates glycyrrhetinic acid (GA) to improve target specificity toward HCC cells. Notably, both drugs exhibited pH-sensitive release profiles, facilitating precise drug release within acidic environments. Our investigation into cellular uptake demonstrated that modified liposomes, GA-IM-LIP@FITC and IM-LIP@FITC, achieved progressively enhanced intracellular accumulation of FITC compared to unmodified liposomes. Competitive inhibition assays utilizing free GA further validated the targeting efficacy of GA. Moreover, the GA-IM-LIP@FITC and IM-LIP@FITC groups exhibited rapid endosomal escape of FITC within the first two hours, in contrast to delayed escape observed in the LIP@FITC group, confirming that the protonation of IM-Chol promotes drug release into the cytosol. In vivo studies substantiated that GA-IM-LIP@DOX/CUR effectively inhibited tumor growth. This research provides significant insights into the design and functionality of the GA-IM-LIP@DOX/CUR liposomal system, underscoring its potential to enhance drug delivery strategies in the treatment of HCC.

Surface engineering of metal-organic framework nanoparticles-based miRNA carrier: Boosting RNA stability, intracellular delivery and synergistic therapy

MicroRNAs (miRNAs) are small noncoding RNAs that are critical for the regulation of multiple physiological and pathological processes, thus holding great clinical potential. However, the therapeutic applications of miRNAs are severely limited by their biological instability and poor intracellular delivery. Herein, we describe a dual-layers surface engineering strategy to design an efficient miRNA delivery nanosystem based on metal-organic frameworks (MOFs) incorporating lipid coating. The resulting nanoparticle system was demonstrated to protect miRNA from ribonuclease degradation, enhance cellular uptake and facilitate lysosomal escape. These ensured effective miRNA mediated gene therapy, which synergized with MOF-specific photodynamic therapy and pre-encapsulated doxorubicin (Dox) chemotherapy to provide a multifunctional with therapeutic effectiveness against cencer cells The mechanisms of miRNA binding and Dox loading were revealed, demonstrating the potential of the present MOFs surface-engineered strategy to overcome their inherent pore-size restriction for macromolecular miRNA carrying, enableefficient co-delivery. In vitro studies revealed the potential of our multifunctional system for miRNA delivery and the demonstrated the therapeutic effectiveness against cancer cells, thereby providing a versatile all-in-one MOFs strategy for delivery of nucleic acids and diverse therapeutic molecules in synergistic therapy.

Bone-Targeted Supramolecular Nanoagonist Assembled by Accurate Ratiometric Herbal-Derived Therapeutics for Osteoporosis Reversal

Developing novel strategies for defeating osteoporosis has become a world-wide challenge with the aging of the population. In this work, novel supramolecular nanoagonists (NAs), constructed from alkaloids and phenolic acids, emerge as a carrier-free nanotherapy for efficacious osteoporosis treatment. These precision nanoagonists are formed through the self-assembly of berberine (BER) and chlorogenic acid (CGA), utilizing noncovalent electrostatic, π-π, and hydrophobic interactions. This assembly results in a 100% drug loading capacity and stable nanostructure. Furthermore, the resulting weights and proportions of CGA and BER within the NAs are meticulously controlled with strong consistency when the CGA/BER assembly feed ratio is altered from 1:1 to 1:4. As anticipated, our NAs themselves could passively target osteoporotic bone tissues following prolonged blood circulation, modulate Wnt signaling, regulate osteogenic differentiation, and ameliorate bone loss in ovariectomy-induced osteoporotic mice. We hope this work will open a new strategy to design efficient herbal-derived Wnt NAs for dealing with intractable osteoporosis.

Multifunctional metal-coordinated Co-assembled carrier-free nanoplatform based on dual-drugs for ferroptosis-mediated cocktail therapy of hepatocellular carcinoma growth and metastasis

The heterogeneity of hepatocellular carcinoma (HCC) and the complexity of the tumor microenvironment (TME) pose challenges to efficient drug delivery and the antitumor efficacy of combined or synergistic therapies. Herein, a metal-coordinated carrier-free nanodrug (named as USFe3+ LA NPs) was developed for ferroptosis-mediated multimodal synergistic anti-HCC. Natural product ursolic acid (UA) was incorporated to enhance the sensitivity of tumor cells to sorafenib (SRF). Surface decoration of cell penetration peptide and epithelial cell adhesion molecule aptamer facilitated the uptake of USFe3+ LA NPs by HepG2 cells. Meanwhile, Fe3+ ions could react with intracellular hydrogen peroxide, generating toxic hydroxyl radical (·OH) for chemodynamical therapy (CDT) and amplified ferroptosis by cystine/glutamate antiporter system (System Xc-), which promoted the consumption of glutathione (GSH) and inhibited the expression of glutathione peroxidase 4 (GPX4). Notably, these all-in-one nanodrugs could inhibit tumor metastasis and induced immunogenic cell death (ICD). Last but not least, the nanodrugs demonstrated favorable biocompatibility, augmenting the immune response against the programmed death-ligand 1 (PD-L1) by increasing cytotoxic T cell infiltration. In vivo studies revealed significant suppression of tumor growth and distant metastasis. Overall, our work introduced a novel strategy for applications of metal-coordinated co-assembled carrier-free nano-delivery system in HCC combination therapy, especially in the realms of cancer metastasis prevention and immunotherapy.

Self-assembly of molecular beacons through metal ion coordination for fluorescence imaging of miRNA in living cells

Fluorescence nanosensors based on functional nucleic acids have been explored as a powerful sensing platform for disease-relevant miRNAs. This work developed a new hybrid nanosensor (Zr-B) through coordination-driven self-assembly of Zr ions and beacons. The prepared nanosensor exhibited high loading efficiency of beacons and could achieve sensitive and specific detection for miRNAs. The hybrid nanosensor could transfer beacons into living cells efficiently and maintain high stability and biocompatibility in the biological environment, achieving effective miRNA fluorescence imaging in living cells. Therefore, the resultant nanosensor holds potential for applications in disease diagnostics.

Tunable metal-organic frameworks assist in catalyzing DNAzymes with amplification platforms for biomedical applications

Various binding modes of tunable metal organic frameworks (MOFs) and functional DNAzymes (Dzs) synergistically catalyze the emergence of abundant functional nanoplatforms. Given their serial variability in formation, structural designability, and functional controllability, Dzs@MOFs tend to be excellent building blocks for the precise "intelligent" manufacture of functional materials. To present a clear outline of this new field, this review systematically summarizes the progress of Dz integration into MOFs (MOFs@Dzs) through different methods, including various surface infiltration, pore encapsulation, covalent binding, and biomimetic mineralization methods. Atomic-level and time-resolved catalytic mechanisms for biosensing and imaging are made possible by the complex interplay of the distinct molecular structure of Dzs@MOF, conformational flexibility, and dynamic regulation of metal ions. Exploiting the precision of DNAzymes, MOFs@Dzs constructed a combined nanotherapy platform to guide intracellular drug synthesis, photodynamic therapy, catalytic therapy, and immunotherapy to enhance gene therapy in different ways, solving the problems of intracellular delivery inefficiency and insufficient supply of cofactors. MOFs@Dzs nanostructures have become excellent candidates for biosensing, bioimaging, amplification delivery, and targeted cancer gene therapy while emphasizing major advancements and seminal endeavors in the fields of biosensing (nucleic acid, protein, enzyme activity, small molecules, and cancer cells), biological imaging, and targeted cancer gene delivery and gene therapy. Overall, based on the results demonstrated to date, we discuss the challenges that the emerging MOFs@Dzs might encounter in practical future applications and briefly look forward to their bright prospects in other fields.

Advance Progress in Assembly Mechanisms of Carrier-Free Nanodrugs for Cancer Treatment

Nanocarriers have been widely studied and applied in the field of cancer treatment. However, conventional nanocarriers still suffer from complicated preparation processes, low drug loading, and potential toxicity of carriers themselves. To tackle the hindrance, carrier-free nanodrugs with biological activity have received increasing attention in cancer therapy. Extensive efforts have been made to exploit new self-assembly methods and mechanisms to expand the scope of carrier-free nanodrugs with enhanced therapeutic performance. In this review, we summarize the advanced progress and applications of carrier-free nanodrugs based on different types of assembly mechanisms and strategies, which involved noncovalent interactions, a combination of covalent bonds and noncovalent interactions, and metal ions-coordinated self-assembly. These carrier-free nanodrugs are introduced in detail according to their assembly and antitumor applications. Finally, the prospects and existing challenges of carrier-free nanodrugs in future development and clinical application are discussed. We hope that this comprehensive review will provide new insights into the rational design of more effective carrier-free nanodrug systems and advancing clinical cancer and other diseases (e.g., bacterial infections) infection treatment.

Coordination-driven FBXW7 DNAzyme-Fe nanoassembly enables a binary switch of breast cancer cell cycle checkpoint responses for enhanced ferroptosis-radiotherapy

Radiotherapy is a mainstream modality for breast cancer treatment that employs ionizing radiation (IR) to damage tumor cell DNA and elevate ROS stress, which demonstrates multiple clinically-favorable advantages including localized treatment and low invasiveness. However, breast cancer cells may activate the p53-mediated cell cycle regulation in response to radiotherapy to repair IR-induced cellular damage and facilitate post-treatment survival. F-Box and WD Repeat Domain Containing 7 (FBXW7) is a promoter of p53 degradation and critical nexus of cell proliferation and survival events. Herein, we engineered a cooperative radio-ferroptosis-stimulatory nanomedicine through coordination-driven self-assembly between ferroptosis-inducing Fe2+ ions and FBXW7-inhibiting DNAzymes and further modification of tumor-targeting dopamine-modified hyaluronic acid (HA). The nanoassembly could be selectively internalized by breast cancer cells and disintegrated in lysosomes to release the therapeutic payload. DNAzyme readily abolishes FBXW7 expression and stabilizes phosphorylated p53 to cause irreversible G2 phase arrest for amplifying post-IR tumor cell apoptosis. Meanwhile, the p53 stabilization also inhibits the SLC7A11-cystine-GSH axis, which combines with the IR-upregulated ROS levels to amplify Fe2+-mediated ferroptotic damage. The DNAzyme-Fe-HA nanoassembly could thus systematically boost the tumor cell damaging effects of IR, presenting a simple and effective approach to augment the response of breast cancer to radiotherapy. STATEMENT OF SIGNIFICANCE: To overcome the intrinsic radioresistance in breast cancer, we prepared co-assembly of Fe2+ and FBXW7-targeted DNAzymes and modified surface with dopamine conjugated hyaluronic acid (HA), which enabled tumor-specific FBXW7-targeted gene therapy and ferroptosis therapy in IR-treated breast cancers. The nanoassembly could be activated in acidic condition to release the therapeutic contents. Specifically, the DNAzymes could selectively degrade FBXW7 mRNA in breast cancer cells to simultaneously induce accumulation of p53 and retardation of NHEJ repair, eventually inducing irreversible cell cycle arrest to promote apoptosis. The p53 stabilization would also inhibit the SLC7A11/GSH/GPX4 axis to enhance Fe2+ mediated ferroptosis. These merits could act in a cooperative manner to induce pronounced tumor inhibitory effect, offering new approaches for tumor radiosensitization in the clinics.

Functional Nucleic Acids-Engineered Bio-Barcode Nanoplatforms for Targeted Synergistic Therapy of Multidrug-Resistant Cancer

Rational design of multifunctional nanomedicines has revolutionized the therapeutic efficacy of cancers. Herein, we have constructed the functional nucleic acids (FNAs)-engineered nanoplatforms based on the concept of a bio-barcode (BBC) for synergistic targeted therapy of multidrug-resistant (MDR) cancer. In this study, the platinum(IV) prodrug is synthesized to covalently link two kinds of FNAs at a rational ratio to fabricate three-dimensional BBC-like DNA nanoscaffolds, accompanied by the one-pot encapsulation of ZnO nanoparticles (NPs) through electrostatic interaction. The multivalent AS1411 aptamers equipped in ZnO@BBCs facilitate specific and efficient endocytosis into MDR human lung adenocarcinoma cells (A549/DDP). In response to the intracellular environment of A549/DDP cells, such as the lysosome-acidic pH and overexpressed GSH, the ZnO NPs are degraded into Zn²⁺ ions for generating reactive oxygen species (ROS), while the Pt(IV) prodrugs are reduced into Pt(II) active species by glutathione (GSH), followed by the release of therapeutic DNAzymes for chemotherapy and gene therapy. In particular, the designed system plays an important role in remodeling the intracellular environment to reverse cancer MDR. On the one hand, the depletion of GSH promotes the downregulation of glutathione peroxidase 4 (GPX4) for amplifying oxidative stress and increasing lipid peroxidation (LPO), resulting in the activation of ferroptosis. On the other hand, the silence of early growth response protein 1 (Egr-1) mRNA by Zn²⁺-dependent DNAzymes directly inhibits the proliferation and migration of MDR cells, which further suppresses the P-glycoprotein (P-gp)-mediated drug efflux. Thus, the proposed nanoplatforms show great promise for the development of versatile therapeutic tools and personalized nanomedicines for MDR cancers.

A Smart Metal-Polyphenol-DNAzyme nanoplatform for Gene-Chemodynamic Synergistic Tumor therapy

DNAzyme-based gene regulation shows great potential for the therapy of many cancers. However, ineffective delivery and insufficient cofactor supply pose challenges for potent gene therapy. In this study, we constructed a smart metal-polyphenol-DNAzyme nanoplatform (TA-Mn@Dz NPs) with intrinsic stability, effective delivery, and cofactor self-supply ability for gene-chemodynamic synergistic tumor therapy. Tannic acid, a plant-derived polyphenol, acts as an intermediate structural unit to mediate the assembly of Mn²⁺/DNAzyme and tumor acid environment-responsive nanocarriers. Intracellularly, the acidic environment triggers the decomposition of TA-Mn@Dz NPs to release DNAzyme and Mn²⁺. The Mn²⁺ ion not only boosts the catalytic cleavage of surviving mRNA for effective gene therapy but also activates chemodynamic therapy (CDT), generating highly toxic ·OH from endogenous H₂O₂. When tail intravenously injected into MCF-7 tumor-bearing mice, the TA-Mn@Dz NPs display desirable synergistic gene-chemodynamic antitumor effects, paving the way for developing DNAzyme-based multifunctional theranostic platforms for biomedical applications. STATEMENT OF SIGNIFICANCE: 1. A smart metal-polyphenol-DNAzyme nanoplatform was constructed for gene-chemodynamic synergistic tumor therapy. 2. Tannic acid act as intermediate structural units to mediate the assembly of Mn²⁺/DNAzyme and tumor acid environment-responsive nanocarriers. 3. The Mn²⁺-ion could not only boost the catalytic cleavage of surviving mRNA for effective gene therapy, but also catalyze endogenous H₂O₂ to form cytotoxic hydroxyl radicals for chemodynamic therapy. 4. Our work paves an extremely simple way to integrate gene therapy with CDT for the dual-catalytic tumor treatment.

Immobilized nanoparticles-mediated enzyme therapy; promising way into clinical development

Enzyme (Enz)-mediated therapy indicated a remarkable effect in the treatment of many human cancers and diseases with an insight into clinical phases. Because of insufficient immobilization (Imb) approach and ineffective carrier, Enz therapeutic exhibits low biological efficacy and bio-physicochemical stability. Although efforts have been made to remove the limitations mentioned in clinical trials, efficient Imb-destabilization and modification of nanoparticles (NPs) remain challenging. NP internalization through insufficient membrane permeability, precise endosomal escape, and endonuclease protection following release are the primary development approaches. In recent years, innovative manipulation of the material for Enz immobilization (EI) fabrication and NP preparation has enabled nanomaterial platforms to improve Enz therapeutic outcomes and provide low-diverse clinical applications. In this review article, we examine recent advances in EI approaches and emerging views and explore the impact of Enz-mediated NPs on clinical therapeutic outcomes with at least diverse effects.

Silencing the Catalase Gene with SiRNA for Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) has been emerging as a promising strategy for cancer treatment. But the CDT efficiency is restricted by the insufficient intracellular hydrogen peroxide (H2O2) level. Herein, we present a method for H2O2 accumulation in tumor cells by silencing the catalase (CAT) gene with siRNA to achieve enhanced CDT. Cu-siRNA nanocomposites are fabricated by self-assembly of Cu2+ and CAT siRNA and then modified with hyaluronic acid (HA) for active tumor targeting. After tumor cell uptake, the released Cu2+ is reduced by highly expressed glutathione (GSH) to Cu+, which then catalyzes H2O2 to produce toxic hydroxyl radicals (•OH) to kill tumor cells. CAT siRNA can efficiently silence the CAT mRNA to inhibit the consumption of H2O2, resulting in H2O2 accumulation. The Cu2+-mediated GSH elimination and siRNA-induced endogenous H2O2 enrichment both potentiate CDT. Cu-siRNA@HA exhibits good biocompatibility and therapeutic efficiency. This work thus paves a new way to supply H2O2 in CDT and may hold potential for clinical application.

Red fluorescent AIEgens based multifunctional nonviral gene vectors for the efficient combination of gene therapy and photodynamic therapy in anti-cancer

Precise molecular engineering of AIEgens-based cationic delivery systems for high transfection efficiency (TE) and effective photodynamic therapy (PDT) holds a huge potential for cancer treatment. Herein, three amphiphiles (DT-C_6/8/12-M) consisting of di(triazole-[12]aneN₃) (M) and 1,1-dicyano-2-phenyl-2-(4-diphenylamino)phenyl-ethylene (DT) units have been developed to achieve luminescent tracking, efficient TE, and effective PDT in vitro and in vivo. These compounds exhibited strong aggregated induced emission (AIE) at 630 nm and mega Stokes shifts of up to 160 nm. They were able to bind DNA into nanoparticles with suitable sizes, positive surface potential, and good biocompatibility in the presence of DOPE. Among them, vector DT-C₁₂-M/DOPE with n-dodecyl linker achieved a transfection efficiency as high as 42.3 folds that of Lipo2000 in PC-3 cell lines. DT-C₁₂-M/DOPE exhibited the capability of successful endo/lysosomal escape and rapid nuclear delivery of pDNA, and the gene delivery process was clearly monitored via confocal laser scanning microscopy. Moreover, efficient reactive oxygen species (ROS) generation by DT-C₁₂-M upon light irradiation led to effective PDT in vitro . We further show that combination of p53 gene therapy and PDT dramatically enhanced cancer therapeutic outcome in vivo. This "three birds, one stone" strategy offers a novel and promising approach for real-time tracking of gene delivery and better cancer treatment.

Structure and functions of Aggregation-Induced Emission-Photosensitizers in anticancer and antimicrobial theranostics

Photosensitizers with Aggregation-Induced Emission (AIE) can allow the efficient light-mediated generation of Reactive Oxygen Species (ROS) based on their complex molecular structure, while interacting with living cells. They achieve better tissue targeting and allow penetration of different wavelengths of Ultraviolet-Visible-Infrared irradiation. Not surprisingly, they are useful for fluorescence image-guided Photodynamic Therapy (PDT) against cancers of diverse origin. AIE-photosensitizers can also function as broad spectrum antimicrobials, capable of destroying the outer wall of microbes such as bacteria or fungi without the issues of drug resistance, and can also bind to viruses and deactivate them. Often, they exhibit poor solubility and cellular toxicity, which compromise their theranostic efficacy. This could be circumvented by using suitable nanomaterials for improved biological compatibility and cellular targeting. Such dual-function AIE-photosensitizers nanoparticles show unparalleled precision for image-guided detection of tumors as well as generation of ROS for targeted PDT in living systems, even while using low power visible light. In short, the development of AIE-photosensitizer nanoparticles could be a better solution for light-mediated destruction of unwanted eukaryotic cells and selective elimination of prokaryotic pathogens, although, there is a dearth of pre-clinical and clinical data in the literature.

Upconversion Luminescence-Boosted Escape of DNAzyme from Endosomes for Enhanced Gene-Silencing Efficacy

Despite the enormous potential of DNAzyme for gene therapy, its efficacy is hampered by the limited endosomal escape capability. Here, we develop a near-infrared (NIR) light-controlled DNAzyme delivery platform to achieve enhanced gene-silencing efficacy. The nanoplatform is composed of therapeutic DNAzyme, photosensitizers (PSs) and upconversion nanoparticles (UCNPs) that can convert NIR light to visible light. The system allows NIR light-activatable generation of cytotoxic reactive oxygen species due to the energy transfer from the UCNPs to PSs, which boosts the endosomal escape of DNAzyme for an improved gene-silencing efficacy. We demonstrate that the nanocomposites represent a promising platform to integrate DNAzyme-based gene therapy with NIR light-triggered photodynamic therapy for combinational tumor treatment. This work highlights a robust approach to combat the current limitations of DNAzyme delivery systems.

Aggregation-Induced Emission Luminogens for Cell Death Research

Cell death is closely related to various diseases, and monitoring and controlling cell death is a promising strategy to develop efficient therapy. Aggregation-induced emission luminogens (AIEgens) are ideal candidates for developing novel theranostic agents because of their intriguing properties in the aggregate state. The rational application of AIE materials in cell death-related research is still in its infancy but has shown great clinical potential. This review discussed the research frontier and our understanding of AIE materials in various subroutines of cell death, including apoptosis, necrosis, immunogenic cell death, pyroptosis, autophagy, lysosome-dependent cell death, and ferroptosis. We hope that the new insights can be offered to this growing field and attract more researchers to provide valuable contributions.

Living Bacteria-Based Immuno-Photodynamic Therapy: Metabolic Labeling of Clostridium butyricum for Eradicating Malignant Melanoma

Due to the complexity, aggressiveness, and heterogeneity of malignant melanoma, it is difficult to eradicate the whole tumor through conventional treatment. Herein, a strategy of metabolic engineering labeled anaerobic oncolytic bacteria (Clostridium butyricum) is demonstrated to achieve the ablation of melanoma. In this system, the metabolic substrate of C. butyricum d-alanine (d-Ala) is first conjugated with a photosensitizer (TPApy) showing aggregation-induced emission (AIE). The yielded metabolic substrate of d-Ala-TPAPy can be metabolically incorporated into bacterial peptidoglycan to form engineered C. Butyricum. Once the engineered C. butyricum is injected into melanoma, the bacteria can only proliferate in an anaerobic zone, stimulate the tumor immune microenvironment, and ablate the tumor hypoxia region. Following that, the relatively rich oxygen content in the peripheral area can induce the death of C. butyricum. The photosensitizer (PS) on the bacteria can subsequently exert a photodynamic effect in the oxygen-rich region and further remove the melanoma residue under light irradiation. Prominent in vivo melanoma ablation results revealed that the engineering oncolytic bacteria can provide a promising regime for solid tumor eradication.

[12]aneN3-Conjugated AIEgens with Two-Photon Imaging Property for Synergistic Gene/Photodynamic Therapy in Vitro and in Vivo

Six amphiphiles (TTC-L-M-1/2/3/4/5/6), each consisting of hydrophilic macrocyclic polyamine triazole-[12]aneN3 (M) and hydrophobic photosensitizer tetraphenylethenethiophene modified cyanoacrylate (TTC) moiety linked with alkyl chains (L), have been designed and synthesized for...

Delivery of therapeutic oligonucleotides in nanoscale

Therapeutic oligonucleotides (TOs) represent one of the most promising drug candidates in the targeted cancer treatment due to their high specificity and capability of modulating cellular pathways that are not readily druggable. However, efficiently delivering of TOs to cancer cellular targets is still the biggest challenge in promoting their clinical translations. Emerging as a significant drug delivery vector, nanoparticles (NPs) can not only protect TOs from nuclease degradation and enhance their tumor accumulation, but also can improve the cell uptake efficiency of TOs as well as the following endosomal escape to increase the therapeutic index. Furthermore, targeted and on-demand drug release of TOs can also be approached to minimize the risk of toxicity towards normal tissues using stimuli-responsive NPs. In the past decades, remarkable progresses have been made on the TOs delivery based on various NPs with specific purposes. In this review, we will first give a brief introduction on the basis of TOs as well as the action mechanisms of several typical TOs, and then describe the obstacles that prevent the clinical translation of TOs, followed by a comprehensive overview of the recent progresses on TOs delivery based on several various types of nanocarriers containing lipid-based nanoparticles, polymeric nanoparticles, gold nanoparticles, porous nanoparticles, DNA/RNA nanoassembly, extracellular vesicles, and imaging-guided drug delivery nanoparticles.

Erythrocyte membrane camouflaged siRNA/chemodrug nanoassemblies for cancer combination therapy

Erythrocyte membrane camouflaged nanoassemblies of siRNA/chemodrugs were constructed, in which cationic amphiphilic chemodrugs interact with negatively charged siRNA and self-assemble into siRNA/chemodrug nanoparticles for combination cancer therapy.

A DNA Nanocomplex Containing Cascade DNAzymes and Promoter-Like Zn-Mn-Ferrite for Combined Gene/Chemo-dynamic Therapy

Sequential control of exogenous chemical events inside cells is a promising way to regulate cell functions and fate. Herein we report a DNA nanocomplex containing cascade DNAzymes and promoter-like Zn-Mn-Ferrite (ZMF), achieving combined gene/chemo-dynamic therapy. The promoter-like ZMF decomposed in response to intratumoral glutathione to release a sufficient quantity of metal ions, thus promoting cascade DNA/RNA cleavage and free radical generation. Two kinds of DNAzymes were designed for sequential cascade enzymatic reaction, in which metal ions functioned as cofactors. The primary DNAzyme self-cleaved the DNA chain with Zn²⁺ as cofactor, and produced the secondary DNAzyme; the secondary DNAzyme afterwards cleaved the EGR-1 mRNA, and thus downregulated the expression of target EGR-1 protein, achieving DNAzyme-based gene therapy. Meanwhile, the released Zn²⁺ , Mn²⁺ and Fe²⁺ induced Fenton/Fenton-like reactions, during which free radicals were catalytically generated and efficient chemo-dynamic therapy was achieved. In a breast cancer mouse model, the administration of DNA nanocomplex led to a significant therapeutic efficacy of tumor growth suppression.

Aggregation-Induced Emission Luminogens with Photoresponsive Behaviors for Biomedical Applications

Fluorescent biomedical materials can visualize subcellular structures and therapy processes in vivo. The aggregation-induced emission (AIE) phenomenon helps suppress the quenching effect in the aggregated state suffered by conventional fluorescent materials, thereby contributing to design strategies for fluorescent biomedical materials. Photoresponsive biomedical materials have attracted attention because of the inherent advantages of light; i.e., remote control, high spatial and temporal resolution, and environmentally friendly characteristics, and their combination with AIE facilitates development of fluorescent molecules with efficient photochemical reactions upon light irradiation. In this review, organic compounds with AIE features for biomedical applications and design strategies for photoresponsive AIE luminogens (AIEgens) are first summarized briefly. Applications are then reviewed, with the employment of photoresponsive and AIE-active molecules for photoactivation imaging, super-resolution imaging, light-induced drug delivery, photodynamic therapy with photochromic behavior, and bacterial targeting and killing being discussed at length. Finally, the future outlook for AIEgens is considered with the aim of stimulating innovative work for further development of this field.

Photoactivatable Biomedical Materials Based on Luminogens with Aggregation-Induced Emission (AIE) Characteristics

Fluorescence probes with aggregation-induced emission (AIE) property are fascinating and vital in biological fields due to their bright fluorescence in the solid state. In contrast, traditional AIE materials are obscured by the off-target effects and lack of spatial and temporal control. Photoactivatable materials with AIE characteristics, whose physicochemical behaviors can be remotely activated by light, provide great potential in biochemical information acquisition with high spatial and temporal resolution. By using AIE-featured photoactivatable fluorescence probes, accurate analysis of the targets of interest is possible. For example, where, when, and to what extent a process is started or stopped by manipulating the non-invasive light accurately. Thus, many researchers are enthusiastic about developing AIE-featured photoactivatable materials and mainly focus on developing novel molecules by rational molecular structure design, and exploring advanced applications by appropriate molecular functionalization. In this review, the recent achievements of photoactivatable materials with AIE characteristics from the aspects involving inherent mechanism of photoactivity, molecular design strategy, and the corresponding applications in biological fields, are summarized. The biological applications are highlighted and discussed, including photoactivatable bioimaging, diagnosis, and photo-controlled therapy. Finally, the challenges and prospects of the AIE-featured photoactivatable materials are also outlined and discussed.

Metal-Based Aggregation-Induced Emission Theranostic Systems

Efficient theranostic systems can realize better outcomes in disease treatment because of precise diagnosis and the concomitant effective therapy. Aggregation-induced emission luminogens (AIEgens) are a unique type of organic emitters with intriguing photophysical properties in the aggregate state. Among the AIEgens studied for biomedical applications, so far, metal-based AIE systems have shown great potential in theranostics due to the enhanced multimodal bioimaging ability and therapeutic effect. This research field has been growing rapidly, and many rationally designed systems with promising activities to cancer and other diseases have been reported recently. In this review, we summarized the recent progress of metal-based AIE materials in bioimaging and biological theranostics, and deciphered the pertinent design strategies. We hope that this review can offer new insights into the development of this growing field.

Carrier Free Photodynamic Synergists for Oxidative Damage Amplified Tumor Therapy

Tumor cells adapt to excessive oxidative stress by actuating reactive oxygen species (ROS)-defensing system, leading to a resistance to oxidation therapy. In this work, self-delivery photodynamic synergists (designated as PhotoSyn) are developed for oxidative damage amplified tumor therapy. Specifically, PhotoSyn are fabricated by the self-assembly of chlorine e6 (Ce6) and TH588 through π-π stacking and hydrophobic interactions. Without additional carriers, nanoscale PhotoSyn possess an extremely high drug loading rate (up to 100%) and they are found to be fairly stable in aqueous phase with a uniform size distribution. Intravenously injected PhotoSyn prefer to accumulate at tumor sites for effective cellular uptake. More importantly, TH588-mediated MTH1 inhibition could destroy the ROS-defensing system of tumor cells by preventing the elimination of 8-oxo-2'-deoxyguanosine triphosphate (8-oxo-dG), thereby exacerbating the oxidative DNA damage induced by the photodynamic therapy (PDT) of Ce6 under light irradiation. As a consequence, PhotoSyn exhibit enhanced photo toxicity and a significant antitumor effect. This amplified oxidative damage strategy improves the PDT efficiency with a reduced side effect by increasing the lethality of ROS without generating superabundant ROS, which would provide a new insight for developing self-delivery nanoplatforms in photodynamic tumor therapy in clinic.

Metal-Coordinated Supramolecular Self-Assemblies for Cancer Theranostics

Metal-coordinated supramolecular nanoassemblies have recently attracted extensive attention as materials for cancer theranostics. Owing to their unique physicochemical properties, metal-coordinated supramolecular self-assemblies can bridge the boundary between traditional inorganic and organic materials. By tailoring the structural components of the metal ions and binding ligands, numerous multifunctional theranostic nanomedicines can be constructed. Metal-coordinated supramolecular nanoassemblies can modulate the tumor microenvironment (TME), thus facilitating the development of TME-responsive nanomedicines. More importantly, TME-responsive organic-inorganic hybrid nanomaterials can be constructed in vivo by exploiting the metal-coordinated self-assembly of a variety of functional ligands, which is a promising strategy for enhancing the tumor accumulation of theranostic molecules. In this review, recent advancements in the design and fabrication of metal-coordinated supramolecular nanomedicines for cancer theranostics are highlighted. These supramolecular compounds are classified according to the order in which the coordinated metal ions appear in the periodic table. Furthermore, the prospects and challenges of metal-coordinated supramolecular self-assemblies for both technical advances and clinical translation are discussed. In particular, the superiority of TME-responsive nanomedicines for in vivo coordinated self-assembly is elaborated, with an emphasis on strategies that enhance the accumulation of functional components in tumors for an ideal theranostic outcome.

Spherical Nucleic Acids for Near-Infrared Light-Responsive Self-Delivery of Small-Interfering RNA and Antisense Oligonucleotide

Herein, we developed a photolabile spherical nucleic acid (PSNA) for carrier-free and near-infrared (NIR) photocontrolled self-delivery of small-interfering RNA (siRNA) and antisense oligonucleotide (ASO). PSNA comprised a hydrophilic siRNA shell with a hydrophobic core containing a peptide nucleic acid-based ASO (pASO) and NIR photosensitizer (PS). The incorporation of a singlet oxygen (¹O₂)-cleavable linker between the siRNA and pASO allowed on-demand disassembly of PSNA in tumor cells once ¹O₂ was produced by the inner PS upon NIR light irradiation. The generated ¹O₂ could also concurrently promote lysosomal escape of the released siRNA and pASO to reach cytosolic targets. Both in vitro and in vivo results demonstrated that, under NIR light irradiation, PSNA could suppress hypoxia inducible factor-1α (HIF-1α) and B-cell lymphoma 2 (Bcl-2) for gene therapy (GT), which further combined photodynamic therapy (PDT) favored by the released PS to inhibit tumor cell growth. Given its carrier-free, NIR-sensitive, designable, and biocompatible merits, PSNA represents a promising self-delivery nanoplatform for cancer therapy.