Mesoporous Silica-Coated Silver Nanoframes as Drug-Delivery Vehicles for Chemo/Starvation/Metal Ion Multimodality Therapy

Amine-functionalized mesoporous silica nanoparticles decorated by silver nanoparticles for delivery of doxorubicin in breast and cervical cancer cells

Nanocarriers have demonstrated promising potential in the delivery of various anticancer drugs and in improving the efficiency of the treatment. In this study, silver nanoparticles (AgNPs) were green-synthesized using the extracts of different parts of the pomegranate plant, including the peel, flower petals, and calyx. To obtain the most efficient extract used for the green synthesis of AgNPs, all three types of synthesized nanoparticles were characterized. Then, (3-Aminopropyl) triethoxysilane-functionalized mesoporous silica nanoparticles (MSNs-APTES) decorated with AgNPs were fabricated via a one-pot green-synthesis method. AgNPs were directly coated on the surface of MSNs-APTES by adding pomegranate extract enriched with a source of reducing agent leading to converting the silver ion to AgNPs. The MSN-APTES-AgNPs (MSNs-AgNPs) have been thoroughly characterized using nanoparticle characterization techniques. In addition, DNA cleavage and hemolysis activities of the synthesized nanoparticles were analyzed, confirming the biocompatibility of synthesized nanoparticles. The Doxorubicin (DOX, as a breast/cervical anti-cancer drug) loading (42.8%) and release profiles were investigated via UV-visible spectroscopy. The fibroblast, breast cancer, and cervical cancer cells' viability against DOX-loaded nanoparticles were also studied. The results of this high drug loading, uniform shape, and small functionalized nanoparticles demonstrated its great potential for breast and cervical cancer management.

Custom-Design of Multi-Stimuli-Responsive Degradable Silica Nanoparticles for Advanced Cancer-Specific Chemotherapy

Chemotherapy is crucial in oncology for combating malignant tumors but often encounters obatacles such as severe adverse effects, drug resistance, and biocompatibility issues. The advantages of degradable silica nanoparticles in tumor diagnosis and treatment lie in their ability to target drug delivery, minimizing toxicity to normal tissues while enhancing therapeutic efficacy. Moreover, their responsiveness to both endogenous and exogenous stimuli opens up new possibilities for integrating multiple treatment modalities. This review scrutinizes the burgeoning utility of degradable silica nanoparticles in combination with chemotherapy and other treatment modalities. Commencing the elucidation of degradable silica synthesis and degradation mechanisms, emphasis is placed on the responsiveness of these materials to endogenous (e.g., pH, redox reactions, hypoxia, and enzymes) and exogenous stimuli (e.g., light and high-intensity focused ultrasound). Moreover, this exploration delves into strategies harnessing degradable silica nanoparticles in chemotherapy alone, coupled with radiotherapy, photothermal therapy, photodynamic therapy, gas therapy, immunotherapy, starvation therapy, and chemodynamic therapy, elucidating multimodal synergies. Concluding with an assessment of advances, challenges, and constraints in oncology, despite hurdles, future investigations are anticipated to augment the role of degradable silica in cancer therapy. These insights can serve as a compass for devising more efficacious combined tumor treatment strategies.

Advancing Cancer Treatment: Enhanced Combination Therapy through Functionalized Porous Nanoparticles

Cancer remains a major global health challenge, necessitating the development of innovative treatment strategies. This review focuses on the functionalization of porous nanoparticles for combination therapy, a promising approach to enhance cancer treatment efficacy while mitigating the limitations associated with conventional methods. Combination therapy, integrating multiple treatment modalities such as chemotherapy, phototherapy, immunotherapy, and others, has emerged as an effective strategy to address the shortcomings of individual treatments. The unique properties of mesoporous silica nanoparticles (MSN) and other porous materials, like nanoparticles coated with mesoporous silica (NP@MS), metal-organic frameworks (MOF), mesoporous platinum nanoparticles (mesoPt), and carbon dots (CDs), are being explored for drug solubility, bioavailability, targeted delivery, and controlled drug release. Recent advancements in the functionalization of mesoporous nanoparticles with ligands, biomaterials, and polymers are reviewed here, highlighting their role in enhancing the efficacy of combination therapy. Various research has demonstrated the effectiveness of these nanoparticles in co-delivering drugs and photosensitizers, achieving targeted delivery, and responding to multiple stimuli for controlled drug release. This review introduces the synthesis and functionalization methods of these porous nanoparticles, along with their applications in combination therapy.

A Bioresponsive Diselenide-functionalized Hydrogel with Cascade Catalytic Activities for Enhanced Local Starvation- and Hypoxia-Activated Melanoma Therapy

Glutathione (GSH) consumption-enhanced cancer therapies represent important potential cancer treatment strategies. Herein, we developed a new multifunctional diselenide-crosslinked hydrogel with glutathione peroxidase (GPx)-like catalytic activity for GSH depletion-enhanced glucose oxidase (GOx)-mediated tumor starvation and hypoxia-activated chemotherapy. By increasing acid and H₂O₂ during GOx-induced tumor starvation, the degradation of the multiresponsive scaffold could be promoted, which led to accelerated release of the loaded drugs. Meanwhile, the overproduced H₂O₂ led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H₂O₂ and subsequent multimodal cancer treatment. Following the GOx-induced amplification of hypoxia, tirapazamine (TPZ) was transformed into the highly toxic benzotriazinyl radical (BTZ·), exhibiting enhanced antitumor activity. This GSH depletion-augmented cancer treatment strategy effectively boosted GOx-mediated tumor starvation and activated the hypoxia drug, leading to significantly enhanced local anticancer efficacy. STATEMENT OF SIGNIFICANCE: There has been a growing interest in depleting intracellular GSH as a potential strategy for improving ROS-based cancer therapy. Herein, a bioresponsive diselenide-functionalized dextran-based hydrogel with GPx-like catalytic activity was developed for GSH consumption-enhanced local starvation- and hypoxia-activated melanoma therapy. Results showed that the overproduced H₂O₂ led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H₂O₂ and subsequent multimodal cancer treatment.

Glucose Metabolism Intervention-Facilitated Nanomedicine Therapy

Ordinarily, cancer cells possess features of abnormally increased nutrient intake and metabolic pathways. The disorder of glucose metabolism is the most important among them. Therefore, starvation therapy targeting glucose metabolism specifically, which results in metabolic disorders, restricted synthesis, and inhibition of tumor growth, has been developed for cancer therapy. However, issues such as inadequate targeting effectiveness and drug tolerance impede their clinical transformation. In recent years, nanomaterial-assisted starvation treatment has made significant progress in addressing these challenges, whether as a monotherapy or in combination with other medications. Herein, representative researches on the construction of nanosystems conducting starvation therapy are introduced. Elaborate designs and interactions between different treatment mechanisms are meticulously mentioned. Not only are traditional treatments based on glucose oxidase involved, but also newly sprung small molecule agents targeting glucose metabolism. The obstacles and potential for advancing these anticancer therapies were also highlighted in this review.

Liposomal Glucose Oxidase for Enhanced Photothermal Therapy and Photodynamic Therapy against Breast Tumors

Organic near-infrared fluorescent dye mediated photothermal therapy (PTT) and photodynamic therapy (PDT) suffer from heat shock response, since, heat shock proteins (HSPs) are overexpressed and can repair the proteins damaged by PTT and PDT. Starvation therapy by glucose oxide (GOx) can inhibit the heat shock response by limiting the energy supply. However, the delivery of sufficient and active GOx remains a challenge. To solve this problem, we utilize liposomes as drug carriers and prepare GOx loaded liposome (GOx@Lipo) with a high drug loading content (12.0%) and high enzymatic activity. The successful delivery of GOx shows excellent inhibition of HSPs and enhances PTT and PDT. Additionally, we apply the same liposome formulation to load near-infrared dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbo cyanine iodide (DiR) and prepare DiR contained liposomes (DiR@Lipo) for PTT and PDT. The liposomal formulation substantially enhances the PTT and PDT properties of DiR as well as the cellular uptake and tumor accumulation. Finally, the combination therapy shows excellent tumor inhibition on 4T1 tumor-bearing mice. Interestingly, we also find that the starvation therapy can efficiently inhibit tumor metastasis, which is probably due to the immunogenic effect. Our work presents a biocompatible and effective carrier for the combination of starvation therapy and phototherapy, emphasizing the importance of auxiliary starvation therapy against tumor metastasis and offering important guidance for clinical PTT and PDT.

Layered and orthogonal assembly of hydrophilic drugs and hydrophobic photosensitizers for enhanced cancer therapy

Combinatorial tumor therapy including chemotherapy and photodynamic therapy (PDT) can compensate for the limitations of each other and significantly increase the therapeutic effect. However, considering the differences of water-soluble characteristics between chemotherapeutic drugs and photosensitizers for photodynamic therapy, simply loading these substances into the same cavities of nanocarriers is rather difficult, leading to the reduced drug loading efficiency. Here, we reported a layered and orthogonal assembly of hydrophilic drugs doxorubicin (Dox) and hydrophobic photosensitizers Chlorin e6 (Ce6) for enhancing the effect of synergistic therapeutics. The assembly was based on polydopamine (PDA) modified with β-cyclodextrin (β-CD) through the addition reaction of -HS in HS-β-CD and-C=C in PDA, then DOX and Ce6 were loaded on the PDA and in the hydrophobic cavities of β-CDs respectively with superior drug loading efficiencies (38.8 ± 0.8% and 5.4 ± 0.3% for DOX and Ce6). PDA was hydrolyzed completely under the lysosomal acidic condition, leading to the controlled release of DOX. Under NIR irradiations, DOX-based chemotherapy was successfully integrated with PDA-based photothermal and Ce6-based photodynamic therapy. Tumor specific aptamer AS1411-modified assembly provides ideal antitumor effects in vitro and in vivo with excellent biocompatibility. Collectively, this layered and orthogonal assembly offers a generalizable solution for delivering matters with distinct aqueous solubility would find broad applications not only in drug delivery but also in bio-nanotechnology.

Role of Solvent in Electron-Phonon Relaxation Dynamics in Core-Shell Au-SiO2 Nanoparticles

Relaxation dynamics of plasmons in Au-SiO₂ core-shell nanoparticles have been followed by femtosecond pump-probe technique. The effect of excitation pump energy and surrounding medium on the time constants associated with the hot electron relaxation has been elucidated. A gradual increase in the electron-phonon relaxation time with pump energy is observed and can be attributed to the higher perturbation of the electron distribution in AuNPs at higher pump energy. Variation in time constants for the electron-phonon relaxation in different solvents is rationalized on the basis of their thermal conductivities, which govern the rate of dissipation of heat of photoexcited electrons in the nanoparticles. On the other hand, phonon-phonon relaxation is found to be much less effective than electron-phonon relaxation for the dissipation of energy of the excited electron and the time constants associated with it remain unaffected by thermal conductivity of the solvent.

Synthesis of Noble Metal M@YSiO2 Yolk-Shell Nanoparticles with Thin Organic/Inorganic Hybrid Outer Shells via an Aqueous Medium Phase

A simple method is proposed for the synthesis of noble metal M@YSiO₂ (M = Au, Pd, Ag) yolk-shell nanoparticles. The effects of synthesis conditions on the preparation of yolk-shell nanoparticles were discussed in detail. According to the different corrosion resistances between inorganic silica and organosilicone in a selective etching solution, yolk-shell nanoparticles with large cavity and thin shell were prepared using the same aqueous medium in a step-by-step synthesis process. Different from traditional methods, this method is facile and efficient because the main synthesis process is carried out in an aqueous phase. This extended method may benefit the synthesis and application of other nanomaterials with a similar yolk-shell structure.

A Review of Mesoporous Silica Nanoparticle Delivery Systems in Chemo-Based Combination Cancer Therapies

Chemotherapy is an important anti-tumor treatment in clinic to date, however, the effectiveness of traditional chemotherapy is limited by its poor selectivity, high systemic toxicity, and multidrug resistance. In recent years, mesoporous silica nanoparticles (MSNs) have become exciting drug delivery systems (DDS) due to their unique advantages, such as easy large-scale production, adjustable uniform pore size, large surface area and pore volumes. While mesoporous silica-based DDS can improve chemotherapy to a certain extent, when used in combination with other cancer therapies MSN based chemotherapy exhibits a synergistic effect, greatly improving therapeutic outcomes. In this review, we discuss the applications of MSN DDS for a diverse range of chemotherapeutic combination anti-tumor therapies, including phototherapy, gene therapy, immunotherapy and other less common modalities. Furthermore, we focus on the characteristics of each nanomaterial and the synergistic advantages of the combination therapies. Lastly, we examine the challenges and future prospects of MSN based chemotherapeutic combination therapies.

Carbon nanocage-based nanozyme as an endogenous H2O2-activated oxygenerator for real-time bimodal imaging and enhanced phototherapy of esophageal cancer

Intelligent phototherapy by theranostic nanosystems that can be activated by a tumor microenvironment has high sensitivity and specificity. However, hypoxia and low drug accumulation in tumors greatly limit its clinical application. Herein, we have designed a cage-like carbon-manganese nanozyme, which effectively relieves tumor hypoxia and delivers numerous photosensitizers (PSs) to the tumor site, for real-time imaging and enhanced phototherapy of esophageal cancer. Specifically, bovine serum albumin (BSA) was used as a template and reducing agent for preparing a BSA-MnO2 nanozyme; then a BSA-MnO2/IR820@OCNC (BMIOC) nanosystem was successfully synthesized by crosslinking BSA-MnO2 on the surface of IR820-loaded carboxylated carbon nanocages (OCNCs). Abundant PSs were successfully delivered to tumor sites via hollow OCNCs, and the final loading rate of IR820 reached 42.8%. The intratumor BMIOC nanosystem can be initiated by a tumor microenvironment to switch on its magnetic resonance (MR) imaging signal, and photothermal therapy (PTT) and photodynamic therapy (PDT) functions. Notably, the BSA-MnO2 nanozyme, with intrinsic catalase (CAT)-like activity, catalyzed endogenous H2O2 for oxygen generation to overcome tumor hypoxia and enhance PDT, thereby leading to more efficient therapeutic effects in combination with OCNC-elevated PTT. In addition, the H2O2-activated and acid-enhanced properties enable our nanosystem to be specific to tumors, protecting normal tissues from damage. By integrating a high drug loading capacity, a hypoxia regulation function, an enlarged phototherapy effect, and bimodal imaging into a nanozyme-mediated nanoreactor, this work realizes a "one for all" system and represents promising clinical translation for efficient esophageal cancer theranostics.

Nanoplatform-based cascade engineering for cancer therapy

Various therapeutic techniques have been studied for treating cancer precisely and effectively, such as targeted drug delivery, phototherapy, tumor-specific catalytic therapy, and synergistic therapy, which, however, evoke numerous challenges due to the inherent limitations of these therapeutic modalities and intricate biological circumstances as well. With the remarkable advances of nanotechnology, nanoplatform-based cascade engineering, as an efficient and booming strategy, has been tactfully introduced to optimize these cancer therapies. Based on the designed nanoplatforms, pre-supposed cascade processes could be triggered under specific conditions to generate/deliver more therapeutic species or produce stronger tumoricidal effects inside tumors, aiming to achieve cancer therapy with increased anti-tumor efficacy and diminished side effects. In this review, the recent advances in nanoplatform-based cascade engineering for cancer therapy are summarized and discussed, with an emphasis on the design of smart nanoplatforms with unique structures, compositions and properties, and the implementation of specific cascade processes by means of endogenous tumor microenvironment (TME) resources and/or exogenous energy inputs. This fascinating strategy presents unprecedented potential in the enhancement of cancer therapies, and offers better controllability, specificity and effectiveness of therapeutic functions compared to the corresponding single components/functions. In the end, challenges and prospects of such a burgeoning strategy in the field of cancer therapy will be discussed, hopefully to facilitate its further development to meet the personalized treatment demands.