Se@SiO2@Au-PEG/DOX NCs as a multifunctional theranostic agent efficiently protect normal cells from oxidative damage during photothermal therapy

Multifunctional Inorganic-Organic Composite Carriers for Synergistic Dual Therapy of Melanoma

Many methods for cancer treatment have been developed. Among them photothermal therapy (PTT) has drawn the most significant attention due to its noninvasiveness, remote control activation, and low side effects. However, a limited depth of light penetration of PTT is the main drawback. To improve the therapeutic efficiency, the development of combined PTT with other therapeutic agents is highly desirable. In this work, we have designed multifunctional composite carriers based on polylactic acid (PLA) particles decorated with gold nanorods (Au NRs) as nanoheaters and selenium nanoparticles (Se NPs) for reactive oxygen species (ROS) production in order to perform a combined PTT against B16-F10 melanoma. To do this, we have optimized the synthesis of PLA particles modified with Se NPs and Au NRs (PLA-Se:Au), studied the cellular interactions of PLA particles with B16-F10 cells, and analyzed in vivo biodistribution and tumor inhibition efficiency. The results of in vitro and in vivo experiments demonstrated the synergistic effect from ROS induced by Se NPs and the heating from Au NRs. In melanoma tumor-bearing mice, intratumoral injection of PLA-Se:Au followed by laser irradiation leads to almost complete elimination of tumor tissues. Thus, the optimal photothermal properties and ROS-generating capacity allow us to recommend PLA-Se:Au as a promising candidate for the development of the combined PTT against melanoma.

Nanocatalytic theranostics with intracellular mutual promotion for ferroptosis and chemo-photothermal therapy

The reactive oxygen species (ROS) produced through the Fenton reaction, induces lipid peroxide (LPO), causing cellular structural damage and ultimately triggering ferroptosis. However, the generation of ROS in the tumor microenvironment (TME) is limited by the catalytic efficiency of the Fenton reaction. Herein, a novel hollow mesoporous silica nanoparticle (HMSN) combined with multi-metal sulfide-doped mesoporous silica nanocatalyzers (NCs) was developed, namely MxSy-HMSN NCs (M represents Cu Mn and Fe, S denotes sulfur). The MxSy-HMSN can dramatically enhanced the ferroptosis by: (1) facilitating the conversion of H2O2 to ·OH through Fenton or Fenton-like reactions through co-catalysis; (2) weakening ROS scavenging systems by depleting the over expressed glutathione (GSH) in TME; (3) providing exceptional photothermal therapy to augment ferroptosis. The MxSy-HMSN can also act as smart cargos for anticancer drug-doxorubicin (DOX). The release of DOX is responsive to GSH/pH/Near-infrared Light (NIR) irradiation at the tumor lesion, significantly improving therapeutic outcomes while minimizing side effects. Additionally, the MxSy-HMSN has demonstrated excellent magnetic resonance imaging (MRI) potential. This smart MxSy-HMSN offer a synergetic approach combining ferroptosis with chemo-photothermal therapy and magnetic resonance imaging (MRI) diagnose, which could be an informative guideline for the design of future NCs.

Scavenging ROS and inflammation produced during treatment to enhance the wound repair efficacy of photothermal injectable hydrogel

Injectable hydrogels with near infrared (NIR) photothermal ability show attractive application prospects in the treatment of wound infection and promoting skin defect repair. Nevertheless, excess reactive oxygen species (ROS) and inflammatory responses caused by bacterial infection and photothermal therapy (PTT) would delay tissue regeneration and wound healing. In this study, a novel NIR photothermal injectable hydrogel with anti-oxidation and anti-inflammation by incorporating α-lipoic acid modified palladium nanoparticles into calcium ions crosslinked sodium alginate hydrogel was developed. The resulting hydrogel facilitated to fill perfectly various irregular wounds, and could convert NIR light into local high-heat to kill >80 % of Escherichia coli and Staphylococcus aureus. Remarkably, the hydrogel exhibited excellent anti-oxidant and anti-inflammatory activity, which could scavenge >60 % of ROS in cells and decrease the relative expression level of tumor necrosis factor-alpha and interleukin-1β genes by 52.9 % and 53.3 % respectively. It was found that the NIR photothermal injectable hydrogel with anti-oxidation and anti-inflammation could effectively reduce ROS and inflammation caused by bacterial infection and PPT. Additionally, it could also enhance wound repair efficiency. The hydrogel is expected to be a potential wound dressing for the treatment of clinical skin defects.

MXene Quantum Dot/Zeolitic Imidazolate Framework Nanocarriers for Dual Stimulus Triggered Tumor Chemo-Phototherapy

It is critical to construct stimuli-responsive multifunctional nanoparticles for the drug delivery system for cancer treatment. Zeolitic imidazolate framework-8 (ZIF-8) has a large specific surface area and decomposes quickly under acidic conditions, which presents an excellent potential in pH-sensitive drug carriers. However, the mere chemotherapeutic drug loaded into ZIF-8 is a monotherapy and may restrict the therapeutic efficacy of malignancies. In this work, an effective nanoparticle-based delivery platform is established to simultaneously encapsulate doxorubicin (DOX) and MXene quantum dot (MQD) in ZIF-8 nanoparticles (MQD@ZIF-8/DOX). Under near-infrared (NIR) laser (808 nm) and UV light (365 nm) irradiation, MQD@ZIF-8 demonstrates a high photothermal conversion efficiency and reactive oxygen species (ROS) production, which shows excellent photothermal therapy and photodynamic therapy effects. Furthermore, the release of DOX-loaded into MQD@ZIF-8 nanoparticles is significantly increased under NIR laser irradiation and at pH 5.6, indicating that acidic conditions and NIR laser irradiation can be effectively combined to stimulate the drug release. The cellular experiments show that MQD@ZIF-8/DOX has an obvious killing effect on HeLa cells and achieves the combined anti-tumor effect of chemotherapy and phototherapy.

Tumor microenvironment responsive self-cascade catalysis for synergistic chemo/chemodynamic therapy by multifunctional biomimetic nanozymes

Chemodynamic therapy (CDT) is an emerging approach to treat cancer based on the tumor microenvironment (TME), but its limited content of endogenous hydrogen peroxide (H₂O₂) weakens the anticancer effects. Herein, a multifunctional biomimetic nanozyme (Se@SiO₂-Mn@Au/DOX, named as SSMA/DOX) is fabricated, which undergoes TME responsive self-cascade catalysis to facilitate MRI guided enhanced chemo/chemodynamic therapy. The SSMA/DOX nanocomposites (NCs) responsively degrade in acidic conditions of tumor to release Se, DOX, Au and Mn²⁺. Mn²⁺ not only enables MRI to guided therapy, but also catalyzes the endogenous H₂O₂ into hydroxyl radical (˙OH) for CDT. In addition, the Au NPs continuously catalyze glucose to generate H₂O₂, enhancing CDT by supplementing a sufficiently reactive material and cutting off the energy supply of the tumor by consuming glucose. Simultaneously, Se enhances the chemotherapy of doxorubicin hydrochloride (DOX) and CDT by upregulating ROS in the tumor cells, achieving remarkable inhibition effect towards tumor. Moreover, SSMA/DOX NCs have good biocompatibility and degradability, which avoid long-term toxicity and side effects. Overall, the degradable SSMA/DOX NCs provide an innovative strategy for tumor microenvironment responsive self-cascade catalysis to enhance tumor therapy.

NIR-responsive sandwich drug loading system for tumor targeting and multiple combined treatment

A novel drug loading system, Au@Si–NN–Si@SiO2, is constructed by a layer-by-layer assembly approach.

The efficiency of photothermal action of gold shell-isolated nanoparticles against tumor cells depends on membrane interactions

Photoinduced hyperthermia with nanomaterials has been proven effective in photothermal therapy (PTT) of tumor tissues, but a precise control in PTT requires determination of the molecular-level mechanisms. In this paper, we determined the mechanisms responsible for the action of photoexcited gold shell-isolated nanoparticles (AuSHINs) in reducing the viability of MCF7 (glandular breast cancer) and especially A549 (lung adenocarcinoma) cells in vitro experiments, while the photoinduced damage to healthy cells was much smaller. The photoinduced effects were more significant than using other nanomaterials, and could be explained by the different effects from incorporating AuSHINs on Langmuir monolayers from lipid extracts of tumoral (MCF7 and A549) and healthy cells. The incorporation of AuSHINs caused similar expansion of the Langmuir monolayers, but Fourier-transform infrared spectroscopy (FTIR) data of Langmuir-Schaefer films (LS) indicated distinct levels of penetration into the monolayers. AuSHINs penetrated deeper into the A549 extract monolayers, affecting the vibrational modes of polar groups and carbon chains, while in MCF7 monolayers penetration was limited to the surroundings of the polar groups. Even smaller insertion was observed for monolayers of the healthy cell extract. The photochemical reactions were modulated by AuSHINs penetration, since upon irradiation the surface area of A549 monolayer decreased owing to lipid chain cleavage by oxidative reactions. For MCF7 monolayers, hydroperoxidation under illumination led to a ca. 5% increase in surface area. The monolayers of healthy cell lipid extract were barely affected by irradiation, consistent with the lowest degree of AuSHINs insertion. In summary, efficient photothermal therapy may be devised by producing AuSHINs capable of penetrating the chain region of tumor cell membranes.

A biocompatible theranostic agent based on stable bismuth nanoparticles for X-ray computed tomography/magnetic resonance imaging-guided enhanced chemo/photothermal/chemodynamic therapy for tumours

Cancer is a leading cause of death worldwide and seriously threatens the health of humans. The current clinical treatments for cancer are not efficient and always lead to significant side effects. Herein, a biocompatible and powerful theranostic agent (Bi@mSiO₂@MnO₂/DOX) is fabricated using a facile stepwise reaction method. The Bi nanoparticles (NPs) are coated by mesoporous silica to protect the Bi NPs from oxidation, which guarantees the stable photothermal effect of the Bi NPs. When the Bi@mSiO₂@MnO₂/DOX nanocomposites (NCs) accumulate in the tumour site, hyperthermia is generated by Bi NPs under near-infrared (NIR) light irradiation for photothermal therapy (PTT), and the generated heat triggers the release of DOX for chemotherapy in the tumour. In addition, the MnO₂ of the NCs responsively catalyses endogenous H₂O₂ to generate O₂, raising the oxygen level to enhance the effect of chemotherapy in the tumour microenvironment (TME), and consumes glutathione (GSH) to produce Mn²⁺ for magnetic resonance (MR) imaging. Under acidic TME conditions, H₂O₂ and Mn²⁺ also produce toxic hydroxyl radical (·OH) for chemodynamic therapy (CDT). Furthermore, the Bi NPs can also be used as excellent contrast agents for X-ray computed tomography (CT) imaging of tumours with a high CT value (6.865 HU mM^-1). The Bi@mSiO₂@MnO₂/DOX NCs exhibit a powerful theranostic performance for CT/MR imaging-guided enhanced PTT/CDT/chemotherapy, which opens a new prospect to rationally design theranostic agents for tumour imaging.

Responsive Degradable Theranostic Agents Enable Controlled Selenium Delivery to Enhance Photothermal Radiotherapy and Reduce Side Effects

Radiotherapy (RT) is a popular clinical therapy method for extending cancer patient survival, but is hampered by severe side effects and the weak therapy effect. Herein, responsive degradable selenium (Se) theranostic agents (Se@SiO₂ @Bi nanocomposites (NCs)) are fabricated, which combine computed tomography (CT) imaging and simultaneously enhance the therapeutic effects of photothermal therapy (PTT) and RT, while reducing the side effects of radiation. The Se@SiO₂ @Bi theranostic agents can accumulate at the tumor site, and responsively decompose to releease Se, avoiding systemic toxicity by the element. Se enhances the effect of PTT/RT, simultaneously reducing the side effects of RT. The Se@SiO₂ @Bi NCs as CT agents also exhibit significantly enhanced contrast imaging performance due to the high atomic number of Bi. More importantly, the Se@SiO₂ @Bi NCs can be rapidly excreted without long-term toxicity, owing to responsive degradation into ultrasmall particles (<5 nm) at the tumor site. In vitro and in vivo results show that the Se@SiO₂ @Bi NCs can remarkably inhibit tumor cells, without causing appreciable toxicity during the treatment. This study opens a new perspective in rationally designing responsive degradable theranostic agents for future tumor therapy with enhanced therapeutic efficacy and lesser side effects.

Facile Interfacial Synthesis of Densely Spiky Gold Nano-Chestnuts With Full Spectral Absorption for Photothermal Therapy

The gold nanostructure is regarded as the most promising photothermal agent due to its strong localized surface plasma resonance (LSPR) effect. In particular, the gold nanostructures with sharp spikes on the surface have higher optical signal enhancement, owing to the sharp tips drastically enhancing the intense nanoantenna effect. However, current approaches for the synthesis of spiky gold nanostructures are either costly, complicated, or uncontrollable. Herein, we report a novel strategy to synthesize gold nano-chestnuts (SGNCs) with sharp spikes as an excellent photothermal agent. The SGNCs were prepared by a facile one-pot interfacial synthetic method, and their controllable preparation mechanism was acquired. The SGNCs exhibited ideal full-spectrum absorption and showed excellent photothermal effect. They have a photothermal conversion efficiency (η) as high as 52.9%, which is much higher than traditional photothermal agents. The in vitro and in vivo results show that the SGNCs could efficiently ablate the tumor cells. Thus, the SGNCs have great potential in photothermal therapy applied in malignant tumors.

Rapid synthesis of a Bi@ZIF-8 composite nanomaterial as a near-infrared-II (NIR-II) photothermal agent for the low-temperature photothermal therapy of hepatocellular carcinoma

Hepatocellular carcinoma is the fourth leading cause of cancer-related deaths globally. Advanced nanomaterials have emerged as effective approaches to liver cancer therapy such as photothermal therapy. However, limited penetration depth of photothermal agents (PTAs) activated in the NIR-I bio-window and thermoresistance due to heat shock proteins restrict the therapeutic efficacy of PTT in HCC. Herein, we prepared a Bi@ZIF-8 (BZ) nanomaterial by a simple one-step reduction method. Then, gambogic acid, a natural inhibitor of Hsp90, was efficiently loaded onto the BZ nanomaterial via physical mixing. The characterization of the nanomaterial and release of GA due to pH change or NIR-light irradiation were separately studied. Photothermal conversion efficiency was calculated, and therapeutic studies were carried out in vitro and in vivo. This nanomaterial exhibited a significantly enhanced drug release rate when the temperature was increased under acidic conditions and had good light stability under laser irradiation and a photothermal conversion efficiency of about 24.4%. In addition, this novel nanomaterial achieved good therapeutic effects with less toxicity in vitro. The BZ nanomaterial loaded with GA caused tumor shrinkage as well as disappearance and effectively downregulated Hsp90 expression in tumors in vivo. Moreover, this novel nanomaterial exhibited good biocompatibility and potential for application in low-temperature PTT with excellent tumor destruction efficacy.

A smart theranostic agent based on Fe-HPPy@Au/DOX for CT imaging and PTT/chemotherapy/CDT combined anticancer therapy

We herein explored a smart Fe-HPPy@Au/DOX theranostic agent for CT diagnosis and PTT/chemotherapy/CDT synergistic treatment of cancer. When the Fe-HPPy@Au/DOX theranostic agent entered the tumor, the tumor environment accelerated the trapped Fe ions release to catalyze the production of ˙OH for CDT. NIR irradiation drove the PTT, and at the same time improved the CDT by increasing the production of ˙OH and triggered DOX release for chemotherapy. In addition, the Au nanoparticles on the surface of Fe-HPPy@Au nanocomposites could be used as a CT imaging agent and catalyzer to produce H₂O₂ for enhanced CDT.

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.