Double-Targeting Explosible Nanofirework for Tumor Ignition to Guide Tumor-Depth Photothermal Therapy

Ultra-small Janus nanoparticle-induced activation of ferroptosis for synergistic tumor immunotherapy

Ferroptosis induced by lipid peroxide (LPO) accumulation is an effective cell death pathway for cancer therapy. However, how to effectively induce ferroptosis at tumor sites and improve its therapeutic effectiveness remains challenging. Here, MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex with tumor-specific targeting and TME response is constructed to overcome immunosuppressive tumor microenvironment (TME) to potentiate the curative effect of ferroptosis by coupling the immune checkpoint indoleamine 2,3-dioxygenase (IDO) inhibitor, NLG919, and hyaluronic acid (HA) to novel ultra-small MnFe2O4@NaGdF4 (MG) nanoparticles with a Janus structure. Firstly, tumor site-precise delivery of MG and NLG919 is achieved with HA targeting. Secondly, MG acts as a magnetic resonance imaging contrast agent, which not only has a good photothermal effect to realize tumor photothermal therapy, but also depletes glutathione and catalyzes the production of reactive oxygen species from endogenous H2O2, which effectively promotes the accumulation of LPO and inhibits the expression of glutathione peroxidase 4, achieving enhanced ferroptosis. Thirdly, NLG919 inhibits the differentiation of Tregs by blocking the tryptophan/kynurenine immune escape pathway, thereby reversing immunosuppressive TME together with the Mn2+-activated cGAS-STING pathway. This work contributes new perspectives for the development of novel ultra-small Janus nanoparticles to reshape immunosuppressive TME and ferroptosis activation. STATEMENT OF SIGNIFICANCE: The Janus structured MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex was synthesized, which can realize the precise delivery of T1/T2 contrast agents MnFe2O4@NaGdF4 (MG) and NLG919 at the tumor site under the ultra-small Janus structural characteristics and targeted molecule HA. The production of ROS, consumption of GSH, and photothermal properties of MGNH make it possible for CDT/PTT activated ferroptosis, and synergistically disrupt and reprogram tumor growth and immunosuppressive tumor microenvironment with NLG919 and Mn2+-mediated activation of cGAS-STING pathway, achieving CDT/PTT/immunotherapy activated by ferroptosis. Meanwhile, ultra-small structural properties of MGNH facilitate subsequent metabolic clearance by the body, allowing for the minimization of potential biotoxicity associated with its prolonged retention.

The dynamic therapeutic effect of a targeted photothermal nanovaccine incorporating toll-like receptor 7 agonist enhanced cancer immunotherapy

Photothermal therapy (PTT) is a noninvasive and effective thermal therapeutic approach. Near-infrared (NIR) light responsive organic nanoparticles (NPs) have been shown to enhance the efficacy of cancer PTT. However, photothermal ablation induced NPs are currently more effective in treating primary and metastatic cancer. Herein, we designed a NIR light responsive theranostic nanosystem that combines PTT with immunotherapy. The caffeic acid doped polyaniline NPs (CA-PANi) were explored for their potential as PTT agents and their ability to mediate immunogenic cell death (ICD). The nano-theranostic agent of CA-PANi functionalized with the RGD (Arg-Gly-Asp) peptide plays a functional role in targeting integrin receptor overexpressed cancer cells. Furthermore, to enhance the immune response in the immune suppressive tumor microenvironment (iTME), imiquimod (R837) a Toll-like receptor 7 agonist that can promote dendritic cell (DC) maturation greatly inhibits tumor growth and tumor recurrence by initiating a strong antitumor immune response. Therefore, combination of PTT and immunotherapy involving CA-PANi-R837-RGD (denoted as CPRR) to improve the therapeutic effect will provide a nanovaccine strategy for targeted antitumor therapy.

Self-assembled thioether-bridged paclitaxel-dihydroartemisinin prodrug for amplified antitumor efficacy-based cancer ferroptotic-chemotherapy

Ferroptosis has been proposed as one form of iron-dependent cell death, overgeneration of high-toxicity hydroxyl radicals (˙OH) tumor sites via Fenton reactions induced cell membrane damage. However, the insufficient intracellular concentrations of both iron and H₂O₂ limited the anticancer performance of ferroptosis. In this study, ROS-sensitive prodrug nanoassemblies composed of a PEG2000-ferrous compound and a single thioether bond bridged dihydroartemisinin-paclitaxel prodrug were constructed, which fully tapped ex/endogenous iron, ferroptosis inducers, and chemotherapeutic agents. Following cellular uptake, the intracellular oxidizing environment accelerated the self-destruction of nanoassemblies and triggered drug release. In addition to the chemotherapeutic effect, the activated dihydroartemisinin was capable of acting as a toxic ˙OH amplifier via the reinforced Fenton reaction, simultaneously depleting intracellular GSH, as well as inducing glutathione peroxidase 4 inactivation, further enhancing ferroptosis-dependent cancer cell proliferation inhibition. Meanwhile, the ROS generation-inductive and cell cycle arrest effect from the paclitaxel augmented synergetic ferroptotic-chemotherapy of cancer. Thus, the prodrug integrating dihydroartemisinin with paclitaxel via a single thioether bond represents a potent nanoplatform to exert amplified ferroptotic-chemotherapy for improved anticancer efficacy.

Surface Engineering of Lanthanide Nanoparticles for Oncotherapy

Surface-modified lanthanide nanoparticles have been widely developed as an emerging class of therapeutics for cancer treatment because they exhibit several unique properties. First, lanthanide nanoparticles exhibit a variety of diagnostic capabilities suitable for various image-guided therapies. Second, a large number of therapeutic molecules can be accommodated on the surface of lanthanide nanoparticles, which can simultaneously achieve combined cancer therapy. Third, multivalent targeting ligands on lanthanide nanoparticles can be easily modified to achieve high affinity and specificity for target cells. Last but not least, lanthanide nanoparticles can be engineered for spatially and temporally controlled tumor therapy, which is critical for developing precise and personalized tumor therapy. Surface-modified lanthanide-doped nanoparticles are widely used in cancer phototherapy. This is due to their unique optical properties, including large anti-Stokes shifts, long-lasting luminescence, high photostability, and the capacity for near-infrared or X-ray excitation. Upon near-infrared irradiation, these nanoparticles can emit ultraviolet to visible light, which activates photosensitizers and photothermal agents to destroy tumor cells. Surface modification with special ligands that respond to tumor microenvironment changes, such as acidic pH, hypoxia, or redox reactions, can turn lanthanide nanoparticles into a smart nanoplatform for light-guided tumor chemotherapy and gene therapy. Surface-engineered lanthanide nanoparticles can include antigens that elicit tumor-specific immune responses, as well as immune activators that boost immunity, allowing distant and metastatic tumors to be eradicated. The design of ligands and surface chemistry is crucial for improving cancer therapy without causing side effects. In this Account, we classify surface-modified lanthanide nanoparticles for tumor therapy into four main domains: phototherapy, radiotherapy, chemotherapy, and biotherapy. We begin by introducing fundamental bioapplications and then discuss recent developments in tumor phototherapy (photodynamic therapy and photothermal therapy), radiotherapy, chemotherapy, and biotherapy (gene therapy and immunotherapy). We also assess the viability of a variety of strategies for eliminating tumor cells through innovative pathways. Finally, future opportunities and challenges for the development of more efficient lanthanide nanoprobes are discussed.

Application of lanthanide-doped upconversion nanoparticles for cancer treatment: a review

With the excellent ability to transform near-infrared light to localized visible or UV light, thereby achieving deep tissue penetration, lanthanide ion-doped upconversion nanoparticles (UCNP) have emerged as one of the most striking nanoscale materials for more effective and safer cancer treatment. Up to now, UCNPs combined with photosensitive components have been widely used in the delivery of chemotherapy drugs, photodynamic therapy and photothermal therapy. Applications in these directions are reviewed in this article. We also highlight microenvironmental tumor monitoring and precise targeted therapies. Then we briefly summarize some new trends and the existing challenges for UCNPs. We hope this review can provide new ideas for future cancer treatment based on UCNPs.

Efficient near-infrared anionic conjugated polyelectrolyte for photothermal therapy

In this work, an anionic conjugated polyelectrolyte (PCP-SO3K), in which the backbone contains alternating 4,4-bis-alkyl-4H-cyclopenta-[2,1-b;3,4-b']-dithiophene and benzene structural units and the charges are provided by pendant sulfonate groups, was synthesized. The ionic nature of PCP-SO3K renders it soluble in water, and PCP-SO3K aqueous solution exhibits good photostability, with two main absorbance bands centered at 490 nm and 837 nm before and after laser irradiation. Its NIR absorption in water, negligible photoluminescence and insignificant intersystem crossing endow PCP-SO3K with efficient photothermal therapy performance, and an effective photothermal conversion efficiency of 56.7% was realized. Thus, PCP-SO3K aqueous solution can be used as an effective photothermal agent for in vivo applications as its photoactivity can be triggered by NIR light and can convert laser energy into thermal energy in a water environment. Of particular importance is the fact that complete tumor remission without recurrence in 4T1 tumor-bearing mice was realized after intravenous injection of PCP-SO3K aqueous solution and laser irradiation (2.0 W cm-2, 808 nm). The results indicate that the application of anionic conjugated polyelectrolytes as photothermal agents in photothermal therapy provides a new platform for the design of photothermal agents for clinical cancer treatment.

A novel self-coated polydopamine nanoparticle for synergistic photothermal-chemotherapy

The combination of photothermal therapy (PTT) and chemotherapy is a promising strategy to overcome the shortcomings of monotherapy. For the first time, we designed a self-coated nanoparticle formed by mesoporous polydopamine (MPDA) core and polydopamine (PDA) shell, which was used to load docetaxel and modified with hyaluronic acid (HA). The obtained nanoparticle can achieve targeted drug delivery and further exert the synergistic effect of PTT and chemotherapy. The MPDA core has high drug loading due to mesopores, and the PDA shell can prevent the drug from releasing in the non-target-site because of the pH-sensitivity of the PDA. Compared with other PDA coated nanoparticle, self-coated nanoparticle has a simpler composition and can avoid the potential toxicity caused by the introduction of other materials. Experimental results showed that it had good photothermal conversion ability both in vivo and in vitro, and could be actively targeted into tumor cells through HA-mediated targeting. Under laser irradiation, it ablated the tumors. Simple ingredient and preparation, good compatibility and obvious therapeutic effect make it have a broad application prospect in tumor therapy.

Nanostructures based on vanadium disulfide growing on UCNPs: simple synthesis, dual-mode imaging, and photothermal therapy

It remains a great challenge to integrate effective photothermal therapeutic materials with upconversion nanoparticles (UCNPs) into one structure with small size. Herein, a new and simple method was developed to combine the luminescent UCNPs with vanadium disulfide (VS2) heterogeneously growing on the UCNPs. VS2 was grown directly on the surface of UCNPs to obtain oil-soluble nanocomposites, UCNPs@VS2. Then polyethylene glycol (mPEG) was functionalized on the surface of the nanocomposites to improve the water solubility, resulting in the integrated nanostructure UCNPs@VS2-mPEG (with an approximate size of 25 nm) for bioimaging and photothermal therapy in vitro. Importantly, cytotoxicity test results show that the final nanostructure has good biocompatibility. Furthermore, due to the excellent photothermal effects of VS2 and the unique imaging function of UCNPs, the nanostructure shows effective photothermal therapy for HeLa cells and was successfully applied in magnetic resonance imaging and upconversion luminescence imaging in vitro. Therefore, this study demonstrates a simple yet powerful method of growing VS2 on the surface of UCNPs, which provides an effective method to establish one integrated nanostructure with a nanoscale advantage for dual-model bioimaging and treatment.

A redox-sensitive core-crosslinked nanosystem combined with ultrasound for enhanced deep penetration of nanodiamonds into tumors

Nanodiamonds (NDs) as drug delivery vehicles are of great significance in anticancer therapy through enhancing drug retention. However, the major barrier to clinical application of NDs is insufficient tumor penetration owing to their strong aggregation and low passive penetration efficiency. Herein, the core-crosslinked pullulan carrier, assembled using the visible light-induced diselenide (Se-Se) bond crosslinking method for encapsulating nanodiamonds-doxorubicin (NDX), is proposed to improve monodispersity. Furthermore, the core-crosslinked diselenide bond provides the nanosystem with redox-responsive capability and improved structural stability in a physiological environment, which prevents premature drug leakage and achieves tumor site-specific controlled release. What's more, ultrasound (US) is utilized to promote nanosystem intratumoral penetration via enlarged tumor vascular endothelium cell gaps. As expected, the nanosystem combined with ultrasound can enhance anti-tumor efficacy with deep penetration and excellent retention performance in a HepG2 xenograft mouse model. This study highlights the ability of the integrated therapeutic paradigm to overcome the limitation of nanodiamonds and the potential for further application in cancer therapy.

Development of a novel anti-tumor theranostic platform: a near-infrared molecular upconversion sensitizer for deep-seated cancer photodynamic therapy

Upconversion-based photon-initiated therapeutic modalities, photodynamic therapy (PDT) in particular, have shown significant clinical potential in deep-seated tumor treatment. However, traditional multiphoton upconversion materials involving lanthanide (ion)-doped upconversion nanoparticles (UCNPs) and two-photon absorption (TPA) dyes often suffer from lots of inherent problems such as unknown systematic toxicity, low reproducibility, and extremely high irradiation intensity for realization of multiphoton upconversion excitation. Herein, for the first time, we report a one-photon excitation molecular photosensitizer (FUCP-1) based on a frequency upconversion luminescence (FUCL) mechanism. Under anti-Stokes (808 nm) excitation, FUCP-1 showed excellent photostability and outstanding upconversion luminescence quantum yield (up to 12.6%) for imaging-guided PDT. In vitro cellular toxicity evaluation presented outstanding inhibition of 4T1 cells by FUCP-1 with 808 nm laser irradiation (the half maximal inhibitory concentration was as low as 2.06 μM). After intravenous injection, FUCP-1 could specifically accumulate at tumor sites and obviously suppress the growth of deep-seated tumors during PDT. More importantly, FUCP-1 could be fully metabolized from the body within 24 h, thus dramatically minimizing systemic toxicity. This study might pave a new way for upconversion-based deep-seated cancer PDT.

Recent Advances in Small Copper Sulfide Nanoparticles for Molecular Imaging and Tumor Therapy

Small copper sulfide nanoparticles (s-Cu_2-xS NPs, 0 < x < 1) with a core size of less than 5.5 nm have unique physicochemical characteristics and pharmacokinetic properties and have attracted substantial attention from researchers in the field of biomedicine in recent years. After exposure to near-infrared (NIR) light, s-Cu_2-xS NPs can rapidly convert light energy into heat for photoacoustic imaging (PAI) and photothermal therapy (PTT). In addition, the potential for magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging, along with the low toxicity and low cost, makes s-Cu_2-xS NPs a promising multifunctional diagnostic reagent. This Review outlines recent advances in s-Cu_2-xS NPs for molecular imaging and tumor therapy and discusses the challenges associated with successful clinical translation.

Recent advances in nanomaterials for enhanced photothermal therapy of tumors

Nowadays, photothermal therapy (PTT) utilizing photothermal conversion agents (PTAs) to generate sufficient heat under near-infrared (NIR) light irradiation for tumor ablation has attracted extensive research attention. Despite the great advancement, the therapeutic efficacy of PTT in tumor treatment is still compromised by several obstacles, such as low photothermal conversion efficiency, poor stability of PTAs, inadequate tumor accumulation and cellular uptake, and thermal-resistance of tumors, as well as tumor recurrence and metastasis. In this review, we highlight recent advances in nanomaterials that focus on overcoming the above obstacles and thus enhancing the therapeutic outcome of PTT. PTAs with improved photothermal performance and modification strategies for efficient PTT are summarized, which are further classified into three main types, utilizing activatable PTAs, improving the local concentration of PTAs, and overcoming intrinsic drawbacks of PTT (e.g., heat shock responses). Furthermore, the limitations and challenges of nanomaterials for enhanced PTT are also discussed.

Multifunctional Supramolecular Materials Constructed from Polypyrrole@UiO-66 Nanohybrids and Pillararene Nanovalves for Targeted Chemophotothermal Therapy

Multifunctional supramolecular nanomaterials capable of targeted and multimodal therapy hold great potential to improve the efficiency of cancer therapeutics. Herein, we report a proof-of-concept nanoplatform for effective chemophotothermal therapy via the integration of folic acid-based active targeting and supramolecular nanovalves-based passive targeting. Inspired by facile surface engineering and designable layer-by-layer assembly concept, we design and synthesize PPy@UiO-66@WP6@PEI-Fa nanoparticles (PUWPFa NPs) to achieve efficient synergistic chemophotothermal therapy, taking advantage of the desirable photothermal conversion capability of polypyrrole nanoparticles (PPy NPs) and high drug-loading capacity of hybrid scaffolds. Significantly, pillararene-based pseudorotaxanes as pH/temperature dual-responsive nanovalves allow targeted drug delivery in pathological environment with sustained release over 4 days, which is complementary to photothermal therapy, and folic acid-conjugated polyethyleneimine (PEI-Fa) at the outmost layer through electrostatic interactions is able to enhance tumor-targeting and therapeutic efficiency. Such PUWPFa NPs showed efficient synergistic chemophotothermal therapy of cervical cancer both in vitro and in vivo. The present strategy offers not only the distinctly targeted drug delivery and release, but also excellent tumor inhibition efficacy of simultaneous chemophotothermal therapy, opening a new avenue for effective cancer treatment.