Tri-stimuli-responsive biodegradable theranostics for mild hyperthermia enhanced chemotherapy

Charge-Reversal Nano-Drug Delivery Systems in the Tumor Microenvironment: Mechanisms, Challenges, and Therapeutic Applications

The charge-reversal nano-drug delivery system (CRNDDS) is a promising system for delivering chemotherapy drugs and has gained widespread application in cancer treatment. In this review, we summarize the recent advancements in CRNDDSs in terms of cancer treatment. We also delve into the charge-reversal mechanism of the CRNDDSs, focusing on the acid-responsive, redox-responsive, and enzyme-responsive mechanisms. This study elucidates how these systems undergo charge transitions in response to specific microenvironmental stimuli commonly found in tumor tissues. Furthermore, this review explores the pivotal role of CRNDDSs in tumor diagnosis and treatment, and their potential limitations. By leveraging the unique physiological characteristics of tumors, such as the acidic pH, specific redox potential, and specific enzyme activity, these systems demonstrate enhanced accumulation and penetration at tumor sites, resulting in improved therapeutic efficacy and diagnostic accuracy. The implications of this review highlight the potential of charge-reversal drug delivery systems as a novel and targeted strategy for cancer therapy and diagnosis.

Polyphosphate-Mediated Crystallographic and Colloidal Stabilization of CuS Nanoparticles: Enhanced NIR-Responsive Chemo-Photothermal Efficacy

Photothermal therapy (PTT) is an emerging treatment modality for cancer management. However, the photothermal agents (PTAs) used in PTT should have sufficient biocompatibility, water dispersibility, and good photoresponsive. In this aspect, water-dispersible and biocompatible linear polyphosphate (LP)-functionalized CuS nanoparticles (LP-CuS NPs) were developed using sodium tripolyphosphate (LP molecule) as a surface passivating agent. The successful formation of the green covellite CuS phase was confirmed by X-ray diffraction and TEM analyses, and its surface functionalization with the LP ligand was evident from X-ray photoelectron spectroscopy, Fourier transform infrared, thermogravimetric analysis, and light scattering measurements. It has been found that the use of LP not only stabilizes the crystallographic covellite CuS phase by overcoming the requirement of a soft ligand but also provides long-term aqueous colloidal stability, which is essential for PTT applications. The aqueous suspension of LP-CuS NPs showed excellent heating efficacy under near infrared (NIR) light irradiation (980 nm) and has a strong binding affinity towards anticancer drug, doxorubicin hydrochloride (DOX). The drug-loaded systems (DOX@LP-CuS NPs) revealed a pH-dependent drug release behavior with higher concentrations in a mild acidic environment. The in vitro studies showed substantial cellular uptake of DOX-loaded systems in cancer cell lines and enhanced toxicity towards them upon irradiation of NIR light through apoptotic induction, suggesting their potential application in chemo-photothermal therapy.

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.

Two-photon fluorescence-guided precise photothermal therapy located in a single cancer cell utilizing bifunctional N-doped carbon quantum dots

The utilization of carbon quantum dots (CQDs) for photothermal therapy has emerged as a hot research topic. However, there has been limited research on killing one single cancer cell which is critical in reducing unnecessary damage to the surrounding healthy tissues. In this work, we developed a two-photon fluorescence-guided precise photothermal therapy in a single human malignant melanoma (A375) cancer cell utilizing bifunctional N-doped CQDs. Resulting from the two-photon fluorescence of the CQDs, one single cancer cell can be located and simultaneously destroyed by the photothermal effect of the same CQDs. Specifically, the balanced two-photon absorption cross-section (7000 GM) and photoluminescence quantum yield (8.4%) of the CQDs enable the fluorescence-guided photothermal treatment to be achieved in only 5 s under the irradiation of 800 nm laser of 27.5 mW, much faster than the control experiment without the guidance of fluorescence. The heat generated by the aggregated CQDs is in sufficient amounts while being confined in a small area, as evidenced by the numerical simulations and photothermal experiments, to limit the range of thermal treatment in the cells. This work provides a new approach for realizing photothermal therapy with minimal damage and establishes a new application scenario of CQDs for precise tumor ablation.

Tumor microenvironment-responsive degradable silica nanoparticles: design principles and precision theranostic applications

Silica nanoparticles have emerged as promising candidates in the field of nanomedicine due to their remarkable versatility and customizable properties. However, concerns about their potential toxicity in healthy tissues and organs have hindered their widespread clinical translation. To address this challenge, significant attention has been directed toward a specific subset of silica nanoparticles, namely degradable silica nanoparticles, primarily because of their excellent biocompatibility and responsive biodegradability. In this review, we provide a comprehensive understanding of degradable silica nanoparticles, categorizing them into two distinct groups: inorganic species-doped and organic moiety-doped silica nanoparticles based on their framework components. Next, the recent progress of tumor microenvironment (TME)-responsive degradable silica nanoparticles for precision theranostic applications is summarized in detail. Finally, current bottlenecks and future opportunities of theranostic nanomedicines based on degradable silica nanoparticles in clinical applications are also outlined and discussed. The aim of this comprehensive review is to shed light on the potential of degradable silica nanoparticles in addressing current challenges in nanomedicine, offering insights into their design, applications in tumor diagnosis and treatment, and paving the way for future advancements in clinical theranostic nanomedicines.

Mn-Doped Nano-Hydroxyapatites as Theranostic Agents with Tumor pH-Amplified MRI-Signal Capabilities for Guiding Photothermal Therapy

Background

The integration of diagnostic and therapeutic functions into a biosafe nanoplatform with intelligent response functions at the tumor microenvironment (TME) is a promising strategy for cancer therapy.

Methods

Mn-doped nano-hydroxyapatite (nHAPMn) nanoparticles were successfully prepared via a simple coprecipitation method for magnetic resonance imaging (MRI)-guided photothermal therapy. This study is the first to report on the use of Mn to render biodegradable hydroxyapatite suitable for MRI and effective photothermal therapy (PTT) simultaneously by regulating the pH of nHAPMn during the preparation process.

Results

Combined with near-infrared (NIR) laser irradiation, a photothermal conversion efficiency of 26% and effective photothermal lethality in vitro were achieved. Moreover, the degradation of nHAPMn led to the release of Mn ions and amplified the MRI signals in an acidic TME, which confirmed that nHAPMn had a good pH-responsive MRI capacity in solid tumors. In animal experiments, tumors in the nHAPMn5+NIR group completely abated after 14 days of treatment, with no significant recurrence during the experiment.

Conclusion

Therefore, nHAPMn is promising as a nanotheranostic agent and can be effective in clinical diagnosis and therapy for treating cancer.

Immunotherapies targeting tumor vasculature: challenges and opportunities

Angiogenesis is a hallmark of cancer biology, and neoadjuvant therapies targeting either tumor vasculature or VEGF signaling have been developed to treat solid malignant tumors. However, these therapies induce complete vascular depletion leading to hypoxic niche, drug resistance, and tumor recurrence rate or leading to impaired delivery of chemo drugs and immune cell infiltration at the tumor site. Achieving a balance between oxygenation and tumor growth inhibition requires determining vascular normalization after treatment with a low dose of antiangiogenic agents. However, monotherapy within the approved antiangiogenic agents' benefits only some tumors and their efficacy improvement could be achieved using immunotherapy and emerging nanocarriers as a clinical tool to optimize subsequent therapeutic regimens and reduce the need for a high dosage of chemo agents. More importantly, combined immunotherapies and nano-based delivery systems can prolong the normalization window while providing the advantages to address the current treatment challenges within antiangiogenic agents. This review summarizes the approved therapies targeting tumor angiogenesis, highlights the challenges and limitations of current therapies, and discusses how vascular normalization, immunotherapies, and nanomedicine could introduce the theranostic potentials to improve tumor management in future clinical settings.

Degradable iron-rich mesoporous dopamine as a dual-glutathione depletion nanoplatform for photothermal-enhanced ferroptosis and chemodynamic therapy

Glutathione (GSH) is a crucial factor in limiting the effects of chemodynamic therapy (CDT) and ferroptosis, an iron-based cell death pathway. Based on this, we constructed iron-rich mesoporous dopamine (MPDA@Fe) nanovehicles with a dual-GSH depletion function by combining MPDA and Fe. Poly (ethylene glycol) (PEG) was further modified to provide desirable stability (PM@Fe) and glucose oxidase (GOx) was grafted onto PM@Fe (GPM@Fe) to address the limitation of hydrogen peroxide (H₂O₂). After the nanoparticles reached the tumor site, the weakly acidic microenvironment promoted the release of Fe. Then Fe^II reacted with H₂O₂ to generate hydroxyl radical (OH) and Fe^III. The generated Fe^III was reduced to Fe^II by GSH, which circularly participated in the Fenton reaction and continuously produced tumor inhibitory free radicals. Meanwhile, GOx consumed glucose to provide H₂O₂ for the reaction. MPDA had also been reported to deplete GSH. Therefore, dual consumption of GSH led to the destruction of intracellular redox balance and inhibition of glutathione-dependent peroxidase 4 (GPX4) expression, resulting in an increase in lipid peroxides (LPO) and further induction of ferroptosis. Additionally, MPDA-mediated photothermal therapy (PTT) raised the temperature of tumor area and produced photothermal-enhanced cascade effects. Hence, the synergistic strategy that combined dual-GSH depletion-induced ferroptosis, enhanced CDT and photothermal cascade enhancement based on MPDA@Fe could provide more directions for designing nanomedicines for cancer treatment.

A Smart Benzothiazole-Based Conjugated Polymer Nanoplatform with Multistimuli Response for Enhanced Synergistic Chemo-Photothermal Cancer Therapy

The combination of chemotherapy and phototherapy has received tremendous attention in multimodal cancer therapy. However, satisfactory therapeutic outcomes of chemo-photothermal therapy (chemo-PTT) still remain challenging. Herein, a biocompatible smart nanoplatform based on benzothiazole-linked conjugated polymer nanoparticles (CPNs) is rationally designed, for effectively loading doxorubicin (DOX) and Mo-based polyoxometalate (POM) through both dynamic chemical bond and intermolecular interactions, with an expectation to obtain new anticancer drugs with multiple stimulated responses to the tumor microenvironment (TME) and external laser irradiation. Controlled drug release of DOX from the obtained nanoformulation (CPNs-DOX-PEG-cRGD-BSA@POM) triggered by both endogenous stimulations (GSH and low pH) and exogenous laser irradiation has been well demonstrated by pharmacodynamics investigations. More intriguingly, incorporating POM into the nanoplatform not only enables the nanomedicine to achieve mild hyperthermia but also makes it exhibit self-assembly behavior in acidic TME, producing enhanced tumor retention. Benefiting from the versatile functions, the prepared CPNs-DOX-PEG-cRGD-BSA@POM exhibited excellent tumor targeting and therapeutic effects in murine xenografted models, showing great potential in practical cancer therapy.

Coiled-coil peptide-based assembly of a plasmonic core-satellite polymer-metal nanocomposite as an efficient photothermal agent for drug delivery applications

Polymer-metal nanocomposites have widespread applications in biomedical fields such as imaging, catalysis, and drug delivery. These particles are characterized by combined organic and inorganic properties. Specifically, photothermal nanocomposites incorporating polymeric and plasmonic nanoparticles (NPs) have been designed for both triggered drug release and as imaging agents. However, the usual design of nanocomposites confers characteristic issues, among which are the decrease of optical properties and resulting low photothermal efficiency, as well as interactions with loaded drugs. Herein, we report the design of a core-satellite polymer-metal nanocomposite assembled by coiled-coil peptides and its superior photothermal efficiency compared to electrostatic-driven nanocomposites which is the standard design. We also found that the orientation of gold nanorods on the surface of polymeric NPs is of importance in the final photothermal efficiency and could be exploited for various applications. Our findings provide an alternative to current wrapping and electrostatic assembly of nanocomposites with the help of coiled-coil peptides and an improvement of the control over core-satellite assemblies with plasmonic NPs. It paves the way to highly versatile assemblies due to the nature of coiled-coil peptides to be easily modified and sensitive to pH or temperature.

A Multifunctional, Highly Biocompatible, and Double-Triggering Caramelized Nanotheranostic System Loaded with Fe3O4 and DOX for Combined Chemo-Photothermal Therapy and Real-Time Magnetic Resonance Imaging Monitoring of Triple Negative Breast Cancer

Purpose

Owing to lack of specific molecular targets, the current clinical therapeutic strategy for triple negative breast cancer (TNBC) is still limited. In recent years, some nanosystems for malignancy treatment have received considerable attention. In this study, we prepared caramelized nanospheres (CNSs) loaded with doxorubicin (DOX) and Fe₃O₄ to achieve the synergistic effect of combined therapy and real-time magnetic resonance imaging (MRI) monitoring, so as to improve the diagnosis and therapeutic effect of TNBC.

Methods

CNSs with biocompatibility and unique optical properties were prepared by hydrothermal method, DOX and Fe₃O₄ were loaded on it to obtain Fe₃O₄/DOX@CNSs nanosystem. Characteristics including morphology, hydrodynamic size, zeta potentials and magnetic properties of Fe₃O₄/DOX@CNSs were evaluated. The DOX release was evaluated by different pH/near-infrared (NIR) light energy. Biosafety, pharmacokinetics, MRI and therapeutic treatment of Fe₃O₄@CNSs, DOX and Fe₃O₄/DOX@CNSs were examined in vitro or in vivo.

Results

Fe₃O₄/DOX@CNSs has an average particle size of 160 nm and a zeta potential of 27.5mV, it demonstrated that Fe₃O₄/DOX@CNSs is a stable and homogeneous dispersed system. The hemolysis experiment of Fe₃O₄/DOX@CNSs proved that it can be used in vivo. Fe₃O₄/DOX@CNSs displayed high photothermal conversion efficiency, extensive pH/heat-induced DOX release. 70.3% DOX release is observed under the 808 nm laser in the pH = 5 PBS solution, obviously higher than pH = 5 (50.9%) and pH = 7.4 (less than 10%). Pharmacokinetic experiments indicated the t1/2β, and AUC_0-t of Fe₃O₄/DOX@CNSs were 1.96 and 1.31 -fold higher than those of DOX solution, respectively. Additionally, Fe₃O₄/DOX@CNSs with NIR had the greatest tumor suppression in vitro and in vivo. Moreover, this nanosystem demonstrated distinct contrast enhancement on T2 MRI to achieve real-time imaging monitoring during treatment.

Conclusion

Fe₃O₄/DOX@CNSs is a highly biocompatible, double-triggering and improved DOX bioavailability nanosystem that combines chemo-PTT and real-time MRI monitoring to achieve integration of diagnosis and treatment of TNBC.

A new chitosan-based thermosensitive nanoplatform for combined photothermal and chemotherapy

Targeting the delivery of anti-cancer drugs to a tumor site is essential for effective treatment and to ensure minimal damage to healthy cells and tissues. In this work, a chitosan-based nanoplatform was constructed for combined photothermal therapy and chemotherapy of breast cancer. The pH-sensitive and biocompatible biopolymer chitosan (CS) was grafted with N-vinylcaprolactam (NVCL) and modified with biotin (Bio), imparting it with temperature sensitive property and also the ability for active targeting. The polymer self-assembled to give nanoparticles (NPs) loaded with indocyanine green (ICG) and doxorubicin (DOX). When the NPs are exposed to near-infrared (NIR) laser irradiation, ICG converts the light to heat, inducing a significant phase transition in the NPs and facilitating the release of the drug cargo. In addition, the solubility of chitosan is increased in the slightly acidic microenvironment of the tumor site, which also promotes drug release. A detailed analysis of the NPs both in vitro and in vivo showed that the carrier system is biocompatible, while the drug-loaded NPs are selectively taken up by cancer cells. Particularly when augmented with NIR irradiation, this leads to potent cell death in vitro and also in an in vivo murine xenograft model of breast cancer.

Antioxidant, Enzyme, and H2O2-Triggered Melanoma Targeted Mesoporous Organo-Silica Nanocomposites for Synergistic Cancer Therapy

The multi-stimuli responsive drug delivery system has recently attracted attention in cancer treatments, since it can reduce several side effects and enhance cancer therapeutic efficacy. Herein, we present the intracellular antioxidant (glutathione, GSH), enzyme (hyaluronidase, HAase), and hydrogen peroxide (H2O2) triggered mesoporous organo-silica (MOS) nanocomposites for multi-modal treatments via chemo-, photothermal, and photodynamic cancer therapies. A MOS nanoparticle was synthesized by two-types of precursors, tetraethyl orthosilicate (TEOS) and bis[3-(triethoxysilyl)propyl] tetrasulfide (BTES), providing large-sized mesopores and disulfide bonds cleavable by GSH. Additionally, we introduced a new β-cyclodextrin-hyaluronic acid (CDHA) gatekeeper system, enabling nanocomposites to form the specific interaction with the ferrocene (Fc) molecule, control the drug release by the HAase and H2O2 environment, as well as provide the targeting ability against the CD44-overexpressing melanoma (B16F10) cells. Indocyanine green (ICG) and doxorubicin (Dox) were loaded in the MOS-Fc-CDHA (ID@MOS-Fc-CDHA) nanocomposites, allowing for hyperthermia and cytotoxic reactive oxygen species (ROS) under an 808 nm NIR laser irradiation. Therefore, we demonstrated that the ID@MOS-Fc-CDHA nanocomposites were internalized to the B16F10 cells via the CD44 receptor-mediated endocytosis, showing the controlled drug release by GSH, HAase, and H2O2 to enhance the cancer therapeutic efficacy via the synergistic chemo-, photothermal, and photodynamic therapy effect.

Stimuli-responsive image-guided nanocarriers as smart drug delivery platforms

INTRODUCTION

In recent years, to improve the precision of drug delivery and reduce toxicity associated from the uncontrolled drug release at off-target locations, extensive efforts have been paid to develop stimuli-responsive nanocarriers, which enable precise control over on-demand drug release due to internal stimuli like pH, redox, enzyme and external stimuli like light, magnetic field, and ultrasound. Moreover, some stimuli-responsive nanocarriers have been strategically incorporated with imaging probes for simultaneous monitoring of the drug delivery process and region of interest for treatment optimization.

AREAS COVERED

In this review, the state-of-art progress in developing stimuli-responsive image-guided nanocarriers are summarized, including their designed strategies, synergistic mechanism, and biomedical applications in cancer therapy, and the current challenges and new perspectives are discussed.

EXPERT OPINION

The stimuli-responsive nanocarriers provide assurance for precise release of drugs and imaging probes, and the molecular imaging techniques can monitor the pharmacokinetics, biodistribution and bioavailability of drugs in vivo, and feedback the drug delivery profile. Therefore, stimuli-responsive image-guided nanocarriers can integrate diagnosis and therapy in one nanoplatform and facilitate optimal therapeutic efficacy.

Developing a Versatile Multiscale Therapeutic Platform for Osteosarcoma Synergistic Photothermo-Chemotherapy with Effective Osteogenicity and Antibacterial Capability

Osteosarcoma is a devastating malignant neoplasm that seriously threatens human health. After an osteosarcoma resection, the simultaneous treatment of tumor recurrence, postoperative infection, and large bone loss remains a formidable challenge clinically. Herein, a versatile multiscale therapeutic platform (Fs-BP-DOX@PDA) is engineered based on NiTi alloys with versatile properties for near-infrared (NIR)-mediated osteosarcoma synergistic photothermo-chemotherapy, bone regeneration, and bacterial elimination. First, an intriguing method for fabricating groovelike micro-nanostructures (Fs-NiTi) through femtosecond laser direct writing to enhance osseointegration with strong contact guidance is proposed. Then, black phosphorus (BP) nanosheets as gratifying photothermal conversion agents, osteogenetic agents, and a drug delivery platform are decorated on Fs-NiTi to construct multiscale hierarchical structures (Fs-BP). Finally, the polydopamine (PDA) modification is utilized to enhance the photothermal performance, biocompatibility, and chemical stability of doxorubicin (DOX)-loaded Fs-BP and endow NIR/pH-dual-responsive DOX release properties. Fs-BP-DOX@PDA effectively induces tumor cell (Saos-2 and MDA-MB-231) death in vitro, completely eradicates osteosarcoma in mice, and observably promotes bone-regeneration bioactivity. Furthermore, it possesses prominent antibacterial efficiencies toward Staphylococcus aureus (99.2%) and Pseudomonas aeruginosa (99.6%). Overall, this work presents a smart comprehensive fabrication methodology to construct a versatile multiscale therapeutic platform for multimodal osteosarcoma treatment and biomedical tissue engineering.

Thermal-Responsive MXene-DNA Hydrogel for Near-Infrared Light Triggered Localized Photothermal-Chemo Synergistic Cancer Therapy

Stimuli-responsive DNA hydrogels are promising candidates for cancer treatment, as they not only possess biocompatible and biodegradable 3D network structures as highly efficient carriers for therapeutic agents but also are capable of undergoing programmable gel-to-solution transition upon external stimuli to achieve controlled delivery. Herein, a promising platform for highly efficient photothermal-chemo synergistic cancer therapy is established by integrating DNA hydrogels with Ti₃ C₂ T_X -based MXene as a photothermal agent and doxorubicin (DOX) as a loaded chemotherapeutic agent. Upon the irradiation of near-infrared light (NIR), temperature rise caused by photothermal MXene nanosheets triggers the reversible gel-to-solution transition of the DOX-loaded MXene-DNA hydrogel, during which the DNA duplex crosslinking structures unwind to release therapeutic agents for efficient localized cancer therapy. Removal of the NIR irradiation results in the re-formation of DNA duplex structures and the hydrogel matrix, and the recombination of free DOX and adaptive hydrogel transformations can also be achieved. As demonstrated by both in vitro and in vivo models, the MXene-DNA hydrogel system, with excellent biocompatibility and injectability, dynamically NIR-triggered drug delivery, and enhanced drug uptake under mild hyperthermia conditions, exhibits efficient localized cancer treatment with fewer side effects to the organisms.

Injectable hyaluronan/MnO2 nanocomposite hydrogel constructed by metal-hydrazide coordinated crosslink mineralization for relieving tumor hypoxia and combined phototherapy

Hydrogel-based drug delivery holds great promise in topical tumor treatment. However, the simple construction of multifunctional therapeutic hydrogels under physiological conditions is still a huge challenge. Herein, for the first time, a multifunctional hyaluronan/MnO₂ nanocomposite (HHM) hydrogel with injectable and self-healing capabilities was constructed under physiological conditions through innovative in situ mineralization-triggered Mn-hydrazide coordination crosslinking. The hydrogel formed from Mn²⁺ and hydrazided hyaluronan under optimized conditions exhibited a high elastic modulus >1 kPa, injectability, self-healing function, stimuli-responsiveness and catalase-like activity. In vitro and in vivo biological experiments demonstrated that our HHM hydrogel could not only efficiently relieve hypoxia by in situ catalytic decomposition of endogenous H₂O₂ into O₂ but also achieve synergistic photodynamic/photothermal therapy of 4T1 breast cancer in a mouse tumor model. This study presented a novel mineralization-driven metal-hydrazide coordination crosslinking approach and developed a multifunctional therapeutic platform for O₂-enhanced efficient topical dual-phototherapy of breast cancer.

Can two-step ablation combined with chemotherapeutic liposomes achieve better outcome than traditional RF ablation? A solid tumor animal study

Objectives: To determine whether two-step ablation using sequential low and high temperature heating can achieve improved outcomes in animal tumor models when combined with chemotherapeutic liposomes (LP). Materials and methods: Balb/c mice bearing 4T1 tumor received paclitaxel-loaded liposomes followed 24 h later by either traditional RFA (70 °C, 5 min) or a low temperature RFA (45 °C, 5 min), or two-step RFA (45 °C 2 min + 70 °C 3 min). Intratumoral drug accumulation and bio-distribution in major organs were evaluated. Periablational drug penetration was evaluated by pathologic staining and the intratumoral interstitial fluid pressure (IFP) was measured directly. For long-term outcomes, mice bearing 4T1 or H22 tumors were randomized into five groups (n = 8 per group): control (no treatment), RFA alone, LP + RFA (45 °C), LP + RFA (70 °C) and LP + RFA (45 + 70 °C). End-point survivals were compared among the different groups. Results: The greater intratumoral drug accumulation (3.35 ± 0.32 vs. 3.79 ± 0.29 × 10⁸ phot/cm²/s at 24 h, p = 0.09), deeper periablational drug penetration (45.7 ± 5.0 vs. 1.6 ± 0.5, p < 0.001), and reduced off-target drug deposition in major organs (liver 96.1 ± 31.6 vs. 47.4 ± 1.5 × 10⁶ phot/cm²/s, p < 0.001) were found when combined with RFA (45 °C) compared to drug alone. For long-term outcomes, 4T1 tumor growth rates for LP + two-step RFA (45 + 70 °C) were significantly slower than those of LP + RFA (70 °C), LP + RFA (45 °C), and RFA alone (P < 0.01 for all comparisons). End point survival for LP + RFA (45 + 70 °C) was also longer than that for LP + RFA (70 °C) (median 16 vs. 10 days, p = 0.003) or LP + RFA 45 °C (11 days, p = 0.009) and RFA alone (8.3 days, p < 0.001) in 4T1 tumor models. The intratumoral IFP after RFA (45 °C) was significantly lower than baseline RFA (3.3 ± 0.8 vs. 19.2 ± 3.1 mmHg, p < 0.001), but was not measurable after RFA (70 °C). Conclusions: A two-step ablation combined with chemotherapeutic liposomes can achieve better survival benefit compared to traditional RFA in animal models.

Nanomaterials in cancer: Reviewing the combination of hyperthermia and triggered chemotherapy

Nanoparticle mediated hyperthermia has been explored as a method to increase cancer treatment efficacy by heating tumours inside-out. With that purpose, nanoparticles have been designed and their properties tailored to respond to external stimuli and convert the supplied energy into heat, therefore inducing damage to tumour cells. Moreover, the combination of hyperthermia with chemotherapy has been described as a more effective strategy due to the synergy between the high temperature and the drug's effects, also associated with a remote controlled and on-demand drug release. In this review, the methods behind nanoparticle mediated hyperthermia, namely material design, external stimuli response and energy conversion will be discussed and critically analysed. We will address the most relevant studies on hyperthermia and temperature triggered drug release for cancer treatment. Finally, the advantages, difficulties and challenges of this therapeutic strategy will be discussed, while giving insight for future developments.

Metal ions-bridged J aggregation mediated nanoassembly composition for breast cancer phototherapy

Recently, the highly ordered J-aggregates of organic dyes with intriguing optical properties have received considerable attention in biomedical applications. Herein, binary metal ions Mn(II)/Fe(III) are used to induce the formation of indocyanine green (ICG) J-aggregates. Further, the sheet-like J-aggregates are able to act as "carriers" for loading hydrophobic chemotherapeutic gambogic acid (GA), realizing the effect of "killing two birds with one stone" for both treatment and delivery. The as-designed nanoassembly is formed spontaneously in aqueous environment via π-π stacking, electrostatic interaction, and hydrophobic force, exhibiting enhanced photostability of ICG and outstanding reactive oxygen species (ROS) generation ability. Moreover, significant inhibition of tumor growth by the synergetic effect of phototherapy and chemotherapy is verified in a subcutaneous 4T1 tumors model. In conclusion, this work not only presents a facile and green approach to manufacture carrier-free nanodrugs, but also establishes a universal platform that has potential application in the co-delivery of near-infrared dye and hydrophobic molecules.

Novel carrier-free, charge-reversal and DNA-affinity nanodrugs for synergistic cascade cancer chemo-chemodynamic therapy

The combination of chemotherapy (CT) and chemodynamic therapy (CDT) is an emerging therapeutic strategy for tumors; however, its therapeutic efficacy is usually impaired by the shortage of high-efficiency intracellular catalysts for CDT and the poor tumor selectivity of CT. To address this concern, novel carrier-free nanodrugs (CMC-DD2) self-assembled from the natural melanin complex (CMC) with a superior CDT performance, and dehydroabietic acid hexamer (DD2) displaying a potent antitumor activity were proposed for the synergistic combination of CT and CDT. CMC-DD2 preferred to enter tumor cells and localize in the nucleus after lysosome escape due to its pH-dependent charge-reversal properties. Nanodrugs internalized by the nucleus directly bound the DNA and altered its conformation. Then, the dissociation of CMC-DD2 was efficiently triggered by intracellular hydrogen peroxide (H₂O₂) with the release of DNA damaging agents, including nitrate anions, hydroxyl radicals (●OH) and DD2. Finally, severe DNA damage induced mitochondrial apoptosis in HepG2 cells. An in vivo assessment further demonstrated the superior tumor selectivity and suppressor capacity and no/low toxicity of the nanodrugs. Overall, novel carrier-free, charge-reversal, nucleus-targeting, biodegradable, and DNA-affinity nanodrugs represent safe and effective platforms for the combination of CT and CDT.

Establishment of Tumor Treating Fields Combined With Mild Hyperthermia as Novel Supporting Therapy for Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with poor prognosis and limited therapeutic options. Alternating electrical fields with low intensity called "Tumor Treating Fields" (TTFields) are a new, non-invasive approach with almost no side effects and phase 3 trials are ongoing in advanced PDAC. We evaluated TTFields in combination with mild hyperthermia. Three established human PDAC cell lines and an immortalized pancreatic duct cell line were treated with TTFields and hyperthermia at 38.5°C, followed by microscopy, assays for MTT, migration, colony and sphere formation, RT-qPCR, FACS, Western blot, microarray and bioinformatics, and in silico analysis using the online databases GSEA, KEGG, Cytoscape-String, and Kaplan-Meier Plotter. Whereas TTFields and hyperthermia alone had weak effects, their combination strongly inhibited the viability of malignant, but not those of nonmalignant cells. Progression features and the cell cycle were impaired, and autophagy was induced. The identified target genes were key players in autophagy, the cell cycle and DNA repair. The expression profiles of part of these target genes were significantly involved in the survival of PDAC patients. In conclusion, the combination of TTFields with mild hyperthermia results in greater efficacy without increased toxicity and could be easily clinically approved as supporting therapy.

Engineering of magnetic nanoparticles as magnetic particle imaging tracers

Magnetic particle imaging (MPI) has recently emerged as a promising non-invasive imaging technique because of its signal linearly propotional to the tracer mass, ability to generate positive contrast, low tissue background, unlimited tissue penetration depth, and lack of ionizing radiation. The sensitivity and resolution of MPI are highly dependent on the properties of magnetic nanoparticles (MNPs), and extensive research efforts have been focused on the design and synthesis of tracers. This review examines parameters that dictate the performance of MNPs, including size, shape, composition, surface property, crystallinity, the surrounding environment, and aggregation state to provide guidance for engineering MPI tracers with better performance. Finally, we discuss applications of MPI imaging and its challenges and perspectives in clinical translation.

Nanoparticles as a Tool in Neuro-Oncology Theranostics

The rapid growth of nanotechnology and the development of novel nanomaterials with unique physicochemical characteristics provides potential for the utility of nanomaterials in theranostics, including neuroimaging, for identifying neurodegenerative changes or central nervous system malignancy. Here we present a systematic and thorough review of the current evidence pertaining to the imaging characteristics of various nanomaterials, their associated toxicity profiles, and mechanisms for enhancing tropism in an effort to demonstrate the utility of nanoparticles as an imaging tool in neuro-oncology. Particular attention is given to carbon-based and metal oxide nanoparticles and their theranostic utility in MRI, CT, photoacoustic imaging, PET imaging, fluorescent and NIR fluorescent imaging, and SPECT imaging.

Sequence-Defined Nanotubes Assembled from IR780-Conjugated Peptoids for Chemophototherapy of Malignant Glioma

Near-infrared (NIR) laser-induced phototherapy through NIR agents has demonstrated the great potential for cancer therapy. However, insufficient tumor killing due to the nonuniform heat or cytotoxic singlet oxygen (1O2) distribution over tumors from phototherapy results in tumor recurrence and inferior outcomes. To achieve high tumor killing efficacy, one of the solutions is to employ the combinational treatment of phototherapy with other modalities, especially with chemotherapeutic agents. In this paper, a simple and effective multimodal therapeutic system was designed via combining chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT) to achieve the polytherapy of malignant glioma which is one of the most aggressive tumors in the brain. IR-780 (IR780) dye-labeled tube-forming peptoids (PepIR) were synthesized and self-assembled into crystalline nanotubes (PepIR nanotubes). These PepIR nanotubes showed an excellent efficacy for PDT/PTT because the IR780 photosensitizers were effectively packed and separated from each other within crystalline nanotubes by tuning IR780 density; thus, a self-quenching of these IR780 molecules was significantly reduced. Moreover, the efficient DOX loading achieved due to the nanotube large surface area contributed to an efficient and synergistic chemotherapy against glioma cells. Given the unique properties of peptoids and peptoid nanotubes, we believe that the developed multimodal DOX-loaded PepIR nanotubes in this work offer great promises for future glioma therapy in clinic.

Low-Temperature Photothermal Therapy: Strategies and Applications

Although photothermal therapy (PTT) with the assistance of nanotechnology has been considered as an indispensable strategy in the biomedical field, it still encounters some severe problems that need to be solved. Excessive heat can induce treated cells to develop thermal resistance, and thus, the efficacy of PTT may be dramatically decreased. In the meantime, the uncontrollable diffusion of heat can pose a threat to the surrounding healthy tissues. Recently, low-temperature PTT (also known as mild PTT or mild-temperature PTT) has demonstrated its remarkable capacity of conquering these obstacles and has shown excellent performance in bacterial elimination, wound healing, and cancer treatments. Herein, we summarize the recently proposed strategies for achieving low-temperature PTT based on nanomaterials and introduce the synthesis, characteristics, and applications of these nanoplatforms. Additionally, the combination of PTT and other therapeutic modalities for defeating cancers and the synergistic cancer therapeutic effect of the combined treatments are discussed. Finally, the current limitations and future directions are proposed for inspiring more researchers to make contributions to promoting low-temperature PTT toward more successful preclinical and clinical disease treatments.

Biodegradable MnFe-hydroxide nanocapsules to enable multi-therapeutics delivery and hypoxia-modulated tumor treatment

Developing drug delivery platforms that can modulate a tumor microenvironment and deliver multiple therapeutics to targeted tumors is critical for efficient cancer treatment. Achieving these platforms still remains a great challenge. Herein, biodegradable nanocapsules based on MnFe hydroxides (H-MnFe(OH)x) have been developed as a new type of cargo delivery with high loading capacity and catalytic activity, enabling synergetic therapy with promoted efficacy by relieving hypoxia in tumor tissues. As a proof of concept, a photosensitizer (indocyanine green, ICG) and a chemotherapeutic drug (doxorubicin, DOX) are co-loaded in nanocapsules and selectively released upon degradation of the nanocapsules in the acidic tumor microenvironment, and are promoted by near infrared irradiation. Meanwhile, Mn2+/Fe3+ ions released from the degradation of nanocapsules catalyze the conversion of H2O2 in a tumor microenvironment into oxygen, which modulates tumor hypoxia and dramatically boosts multimodal therapies. Remarkable synergistic anticancer outcomes have been demonstrated both in vitro and in vivo, paving the way towards future multifunctional therapeutic platforms.

Engineered non-invasive functionalized dendrimer/dendron-entrapped/complexed gold nanoparticles as a novel class of theranostic (radio)pharmaceuticals in cancer therapy

Nanomedicine represents a very significant contribution in current cancer treatment; in addition to surgical intervention, radiation and chemotherapeutic agents that unfortunately also kill healthy cells, inducing highly deleterious and often life-threatening side effects in the patient. Of the numerous nanoparticles used against cancer, gold nanoparticles had been developed for therapeutic applications. Inter alia, a large variety of dendrimers, i.e. soft artificial macromolecules, have turned up as non-viral functional nanocarriers for entrapping drugs, imaging agents, and targeting molecules. This review will provide insights into the design, synthesis, functionalization, and development in biomedicine of engineered functionalized hybrid dendrimer-tangled gold nanoparticles in the domain of cancer theranostic. Several aspects are highlighted and discussed such as 1) dendrimer-entrapped gold(0) hybrid nanoparticles for the targeted imaging and treatment of cancer cells, 2) dendrimer encapsulating gold(0) nanoparticles (Au DENPs) for the delivery of genes, 3) Au DENPs for drug delivery applications, 4) dendrimer encapsulating gold radioactive nanoparticles for radiotherapy, and 5) dendrimer/dendron-complexed gold(III) nanoparticles as technologies to take down cancer cells.

BSA/Silver Nanoparticle-Loaded Hydrogel Film for Local Photothermal Treatment of Skin Cancer

PURPOSE

To develop a hydrogel film containing bovine serum albumin (BSA)-coated silver nanoparticles (BSA/AgNP) and evaluate its applicability for topical photothermal treatment (PTT) of skin cancer.

METHODS

BSA/AgNP-loaded hydrogel films were prepared and their swelling, bioadhesive, mechanical, and photothermal properties were characterized in vitro and in vivo.

RESULTS

The synthesized BSA/AgNP exhibited a narrow size distribution with good size stability and, notably, possessed great photothermal activity that could stably maintain through repetitive laser irradiation. The BSA/AgNP-loaded hydrogel films showed favorable swelling, bioadhesive, tensile, and photothermal properties. Based on these results, when tested the anti-cancer effects in B16F10 s.c. tumor-bearing mice, the PTT with the topical treatment of BSA/AgNP-loaded hydrogel films could significantly inhibit the tumor growth by a single treatment with no apparent toxicity.

CONCLUSIONS

Overall, the results of this study demonstrated that the BSA/AgNP-loaded hydrogel films may serve as an effective but safe topical PTT agent for the treatment of skin cancer.

Advances in Multiple Stimuli-Responsive Drug-Delivery Systems for Cancer Therapy

Nanomedicines afford unique advantages in therapeutic intervention against tumors. However, conventional nanomedicines have failed to achieve the desired effect against cancers because of the presence of complicated physiological fluids and the tumor microenvironment. Stimuli-responsive drug-delivery systems have emerged as potential tools for advanced treatment of cancers. Versatile nano-carriers co-triggered by multiple stimuli in different levels of organisms (eg, extracorporeal, tumor tissue, cell, subcellular organelles) have aroused widespread interest because they can overcome sequential physiological and pathological barriers to deliver diverse therapeutic “payloads” to the desired targets. Furthermore, multiple stimuli-responsive drug-delivery systems (MSR-DDSs) offer a good platform for co-delivery of agents and reversing multidrug resistance. This review affords a comprehensive overview on the “landscape” of MSR-DDSs against tumors, highlights the design strategies of MSR-DDSs in recent years, discusses the putative advantage of oncotherapy or the obstacles that so far have hindered the clinical translation of MSR-DDSs.

Hsp90 inhibitor-loaded IR780 micelles for mitochondria-targeted mild-temperature photothermal therapy in xenograft models of human breast cancer

Mitochondria-targeted mild-temperature photothermal therapy (MT-PTT) is a promising strategy that can maximize anticancer effects and reduce adverse reactions. Here, a novel photosensitizer with mitochondrial targeting based on IR780 iodide and heat shock protein 90 inhibitor (BIIB021), which can passively accumulate in MCF-7 cells and achieve effective MT-PTT effect is synthesized. The prepared PEG-IR780-BIIB021 nano-micelles possess considerable biocompatibility and biological stability, with an encapsulation efficiency of about 84% for BIIB021. They can selectively enrich in mitochondria, and release BIIB021 after NIR irradiation to reduce cell tolerance to heat, thereby reducing the mitochondrial membrane potential and rapidly affecting key intrinsic apoptotic factors (Cyt-C, Caspase-9, Bcl-2 and Bax) to achieve the effect of MT-PTT. It is believed that mitochondria-targeted MT-PTT generated by the PEG-IR780-BIIB021 nano-micelles is a promising therapeutic strategy in clinical practice.

Fabrication of doxorubicin-gated mesoporous polydopamine nanoplatforms for multimode imaging-guided synergistic chemophotothermal therapy of tumors

A versatile theranostic agent that integrated with therapeutic and diagnostic functions is extremely essential for cancer theranostic. Herein, a multifunctional theranostic nanoplatform (PFP@MPDA-DOX) based on perfluoropentane (PFP) encapsulated mesoporous polydopamine (MPDA) is elaborately designed, followed by gating of drug doxorubicin (DOX) for preventing cargo leaking. The MPDA with pH-responsive biodegradation behavior was served as nanocarrier, which also endows the nanoplatform with a large cavity for PFP filling. The nanoparticles were then gated with DOX molecule by Michael addition and/or Schiff base reaction to shield the leaking of PFP during the blood circulation before the tumor tissue is reached. Also, such nanotheranostic exhibits high photothermal conversion efficiency of 45.6%, which can act as an intelligent nanosystem for photothermal therapy (PTT) and photoacoustic (PA) imaging. Moreover, the liquid-gas phase transition of PFP arising upon exposure to an 808 nm laser and thus produced the bubbles for ultrasound (US) imaging. The subsequent PFP@MPDA-DOX-mediated synergetic chemotherapy (contributed by the DOX gatekeeper) and PTT (contributed by the MPDA) shows excellent anticancer activity, which has been systematically evaluated both in vitro and in vivo. All these positive results certify that the facile incorporation of the antitumor drug gatekeeper and MPDA into one theranostic nanoplatform shows general potential for multimode PA/US imaging and combination chemotherapy/PTT of tumors.

Folate functionalized pH-sensitive photothermal therapy traceable hollow mesoporous silica nanoparticles as a targeted drug carrier to improve the antitumor effect of doxorubicin in the hepatoma cell line SMMC-7721

In this paper, we prepared doxorubicin-loaded folic acid-functionalized pH-sensitive photothermal therapy (PTT) traceable hollow mesoporous silica nanoparticles (DOX-HPCF) as a drug carrier for liver cancer treatment. According to TEM characterization, hollow mesoporous silica nanoparticles (HMSN) are monodispersed spherical particles with hollow structure. In vitro drug release experiments showed that HPCF exhibited pH-sensitive release. Cell uptake experiments showed that HPCF was successfully absorbed by SMMC-7721 cells. In addition, DOX-HPCF significantly inhibited the proliferation of SMMC-7721 cells, and the near-infrared (NIR) light group showed a more obvious inhibitory effect. In vivo anti-tumor experiments showed that DOX-HPCF-assisted PTT inhibited tumor growth significantly. Therefore, HPCF is a promising photothermotherapy carrier for the treatment of liver cancer.

The Coppery Age: Copper (Cu)-Involved Nanotheranostics

As an essential trace element in the human body, transitional metal copper (Cu) ions are the bioactive components within the body featuring dedicated biological effects such as promoting angiogenesis and influencing lipid/glucose metabolism. The recent substantial advances of nanotechnology and nanomedicine promote the emerging of distinctive Cu-involved biomaterial nanoplatforms with intriguing theranostic performances in biomedicine, which are originated from the biological effects of Cu species and the physiochemical attributes of Cu-composed nanoparticles. Based on the very-recent significant progresses of Cu-involved nanotheranostics, this work highlights and discusses the principles, progresses, and prospects on the elaborate design and rational construction of Cu-composed functional nanoplatforms for a diverse array of biomedical applications, including photonic nanomedicine, catalytic nanotherapeutics, antibacteria, accelerated tissue regeneration, and bioimaging. The engineering of Cu-based nanocomposites for synergistic nanotherapeutics is also exemplified, followed by revealing their intrinsic biological effects and biosafety for revolutionizing their clinical translation. Finally, the underlying critical concerns, unresolved hurdles, and future prospects on their clinical uses are analyzed and an outlook is provided. By entering the "Copper Age," these Cu-involved nanotherapeutic modalities are expected to find more broad biomedical applications in preclinical and clinical phases, despite the current research and developments still being in infancy.

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.

Mesoporous Silica Nanoparticles as Theranostic Antitumoral Nanomedicines

Nanoparticles have become a powerful tool in oncology not only as carrier of the highly toxic chemotherapeutic drugs but also as imaging contrast agents that provide valuable information about the state of the disease and its progression. The enhanced permeation and retention effect for loaded nanocarriers in tumors allow substantial improvement of selectivity and safety of anticancer nanomedicines. Additionally, the possibility to design stimuli-responsive nanocarriers able to release their payload in response to specific stimuli provide an excellent control on the administered dosage. The aim of this review is not to present a comprehensive revision of the different theranostic mesoporous silica nanoparticles (MSN) which have been published in the recent years but just to describe a few selected examples to offer a panoramic view to the reader about the suitability and effectiveness of these nanocarriers in the oncology field.

Recent Development to Explore the Use of Biodegradable Periodic Mesoporous Organosilica (BPMO) Nanomaterials for Cancer Therapy

Porous nanomaterials can be used to load various anti-cancer drugs efficiently and deliver them to a particular location in the body with minimal toxicity. Biodegradable periodic mesoporous organosilica nanoparticles (BPMOs) have recently emerged as promising candidates for disease targeting and drug delivery. They have a large functional surface and well-defined pores with a biodegradable organic group framework. Multiple biodegradation methods have been explored, such as the use of redox, pH, enzymatic activity, and light. Various drug delivery systems using BPMO have been developed. This review describes recent advances in the biomedical application of BPMOs.

NIR Stimulus-Responsive PdPt Bimetallic Nanoparticles for Drug Delivery and Chemo-Photothermal Therapy

The combination of chemotherapy and phototherapy has attracted increasing attention for cancer treatment in recent years. In the current study, porous PdPt bimetallic nanoparticles (NPs) were synthesized and used as delivery carriers for the anti-cancer drug doxorubicin (DOX). DOX@PdPt NPs were modified with thiol functionalized hyaluronic acid (HA-SH) to generate DOX@PdPt@HA NPs with an average size of 105.2 ± 6.7 nm. Characterization and in vivo and in vitro assessment of anti-tumor effects of DOX@PdPt@HA NPs were further performed. The prepared DOX@PdPt@HA NPs presented a high photothermal conversion efficiency of 49.1% under the irradiation of a single 808 nm near-infrared (NIR) laser. Moreover, NIR laser irradiation-induced photothermal effect triggered the release of DOX from DOX@PdPt@HA NPs. The combined chemo-photothermal treatment of NIR-irradiated DOX@PdPt@HA NPs exerted a stronger inhibitory effect on cell viability than that of DOX or NIR-irradiated PdPt@HA NPs in mouse mammary carcinoma 4T1 cells in vitro. Further, the in vivo combination therapy, which used NIR-irradiated DOX@PdPt@HA NPs in a mouse tumor model established by subcutaneous inoculation of 4T1 cells, was demonstrated to achieve a remarkable tumor-growth inhibition in comparison with chemotherapy or photothermal therapy alone. Results of immunohistochemical staining for caspase-3 and Ki-67 indicated the increased apoptosis and decreased proliferation of tumor cells contributed to the anti-tumor effect of chemo-photothermal treatment. In addition, DOX@PdPt@HA NPs induced negligible toxicity in vivo. Hence, the developed nanoplatform demonstrates great potential for applications in photothermal therapy, drug delivery and controlled release.

Biodegradable Mesoporous Organosilica Nanosheets for Chemotherapy/Mild Thermotherapy of Cancer: Fast Internalization, High Cellular Uptake, and High Drug Loading

The choice of nanocarriers is crucial to fabricate ideal therapeutic nanoplatform in the treatment of cancer. Considering the advantages brought by the two-dimensional (2D) materials with atomic thickness in drug loading and cellular uptake, herein, novel 2D biodegradable mesoporous organosilica nanosheets (MONSs) are presented, and their application in chemotherapy/mild thermotherapy of cancer is studied by loading chemotherapy drug doxorubicin (DOX) and conjugating ultrasmall CuS nanoparticles. It is found that the loading of DOX in MONSs is as high as 859 μg/mg due to their large surface area and intermediate void structure. The release of DOX from MONSs is intelligently controlled by pH value, glutathione (GSH) concentration, and laser irradiation. Excitingly, in comparison with traditional spherical mesoporous organosilica nanoparticles, as-prepared MONSs not only show more rapid degradation but also exhibit faster internalization and higher cellular uptake efficiency due to their larger aspect ratios and unique cellular internalization approach of 2D materials. A mild thermotherapy induced by ultrasmall CuS nanoparticles can further promote the cellular uptake and improve chemotherapy efficacy. The in vitro and in vivo experimental results reveal that the theranostic nanoplatform based on degradable MONSs has excellent biocompatibility and anticancer effects. Therefore, MONSs are expected to be a competitive alternative to existing silica-based nanomaterials in antitumor treatment.

Programmable NIR-II Photothermal-Enhanced Starvation-Primed Chemodynamic Therapy using Glucose Oxidase-Functionalized Ancient Pigment Nanosheets

Chemodynamic therapy (CDT) has attracted considerable attention recently, but the poor reaction kinetics restrict its practical utility in clinic. Herein, glucose oxidase (GOx) functionalized ancient pigment nanosheets (SrCuSi₄ O₁₀ , SC) for programmable near-infrared II (NIR-II) photothermal-enhanced starvation primed CDT is developed. The SC nanosheets (SC NSs) are readily exfoliated from SC bulk suspension in water and subsequently functionalized with GOx to form the nanocatalyst (denoted as SC@G NSs). Upon laser irradiation, the photothermal effect of SC NSs can enhance the catalytic activity of GOx for NIR-II photothermal-enhanced starvation therapy, which effectively eliminates intratumoral glucose and produces abundant hydrogen peroxide (H₂ O₂ ). Importantly, the high photothermal-conversion efficiency (46.3%) of SC@G NSs in second biological window permits photothermal therapy of deep-seated tumors under the guidance of NIR-II photoacoustic imaging. Moreover, the acidity amplification due to gluconic acid generation will in turn accelerate the degradation of SC NSs, facilitating the release of strontium (Sr) and copper (Cu) ions. Both the elevated H₂ O₂ and the released ions will prime the Cu²⁺ /Sr²⁺ -H₂ O₂ reaction for enhanced CDT. Thus, a programmable NIR-II photothermal-enhanced starvation primed CDT is established to combat cancer with minimal side effects.

Rational design of semiconducting polymer brushes as cancer theranostics

Photonic theranostics (PTs) generally contain optical agents for the optical sensing of biomolecules and therapeutic components for converting light into heat or chemical energy. Semiconducting polymer nanoparticles (SPNs) as advanced PTs possessing good biocompatibility, stable photophysical properties, and sensitive and tunable optical responses from the ultraviolet to near-infrared (NIR) II window (300-1700 nm) have recently aroused great interest. Although semiconducting polymers (SPs) with various building blocks have been synthesized and developed to meet the demands of biophotonic applications, most of the SPNs were made by a nanoprecipitation method that used amphiphilic surfactants to encapsulate SPs. Such binary SP micelles usually exhibit weakened photophysical properties of SPs and undergo dissociation in vivo. SP brushes (SPBs) are products of functional post-modification of SP backbones, which endows unique features to SPNs (e.g. enhanced optical properties and multiple chemical reaction sites for the conjunction of organic/inorganic imaging agents and therapeutics). Furthermore, the SPB-based SPNs can be highly stable due to supramolecular self-assembly and/or chemical crosslinking. In this review, we highlight the recent progress in the development of SPBs for advanced theranostics.