Cell membrane covered polydopamine nanoparticles with two-photon absorption for precise photothermal therapy of cancer

Three musketeers of PDA-based MRI contrasting and therapy

Polydopamine (PDA) stands as a versatile material explored in cancer nanomedicine for its unique properties, offering opportunities for multifunctional drug delivery platforms. This study explores the potential of utilizing a one-pot synthesis to concurrently integrate Fe, Gd and Mn ions into porous PDA-based theranostic drug delivery platforms called Ferritis, Gadolinis and Manganis, respectively. Our investigation spans the morphology, magnetic properties, photothermal characteristics and cytotoxicity profiles of those potent nanoformulations. The obtained structures showcase a spherical morphology, robust magnetic response and promising photothermal behaviour. All of the presented nanoparticles (NPs) display pronounced paramagnetism, revealing contrasting potential for MRI imaging. Relaxivity values, a key determinant of contrast efficacy, demonstrated competitive or superior performance compared to established, used contrasting agents. These nanoformulations also exhibited robust photothermal properties under near infra-red irradiation, showcasing their possible application for photothermal therapy of cancer. Our findings provide insights into the potential of metal-doped PDA NPs for cancer theranostics.

Metal-Coordinated Polydopamine Structures for Tumor Imaging and Therapy

Meticulously engineered nanomaterials achieve significant advances in the diagnosis and therapy of solid tumors by improving tumor delivery efficiency; and thereby, enhancing imaging and therapeutic efficacy. Currently, polydopamine (PDA) attracts widespread attention because of its biocompatibility, simplicity of preparation, abundant surface groups, and high photothermal conversion efficiency, which can be applied in drug delivery, photothermal therapy, theranostics, and other nanomedicine fields. Inspired by PDA structures that are rich in catechol and amino functional groups that can coordinate with various metal ions, which have charming qualities and characteristics, metal-coordinated PDA structures are exploited for tumor theranostics, but are not thoroughly summarized. Herein, this review summarizes the recent progress in the fabrication of metal-coordinated PDA structures and their availabilities in tumor imaging and therapy, with further in-depth discussion of the challenges and future perspectives of metal-coordinated PDA structures, with the aim that this systematic review can promote interdisciplinary intersections and provide inspiration for the further growth and clinical translation of PDA materials.

A functionalized cell membrane biomimetic nanoformulation based on layered double hydroxide for combined tumor chemotherapy and sonodynamic therapy

The development of nanoformulations with simple compositions that can exert targeted combination therapy still remains a great challenge in the area of precision cancer nanomedicine. Herein, we report the design of a multifunctional nanoplatform based on methotrexate (MTX)-loaded layered double hydroxide (LDH) coated with chlorin e6 (Ce6)-modified MCF-7 cell membranes (CMM) for combined chemo/sonodynamic therapy of breast cancer. LDH nanoparticles were in situ loaded with MTX via coprecipitation, and coated with CMM that were finally functionalized with phospholipid-modified Ce6. The created nanoformulation of LDH-MTX@CMM-Ce6 displays good colloidal stability under physiological conditions and can release MTX in a pH-dependent manner. We show that the formulation can homologously target breast cancer cells, and induce their significant apoptosis through arresting the cell cycle via cooperative MTX-based chemotherapy and ultrasound (US)-activated sonodynamic therapy. The assistance of US can not only trigger sonosensitizer Ce6 to produce reactive oxygen species, but also enhance the cellular uptake of LDH-MTX@CMM-Ce6 via an acoustic cavitation effect. Upon intravenous injection and US irradiation, LDH-MTX@CMM-Ce6 displays an admirable antitumor performance towards a xenografted breast tumor mouse model. Furthermore, the modification of Ce6 on the CMM endows the LDH-based nanoplatform with fluorescence imaging capability. The developed LDH-based nanoformulation here provides a general intelligent cancer nanomedicine platform with simple composition and homologous targeting specificity for combined chemo/sonodynamic therapy and fluorescence imaging of tumors.

Shape-Regulated Photothermal-Catalytic Tumor Therapy Using Polydopamine@Pt Nanozymes with the Elicitation of an Immune Response

Recently, nanozyme-based photothermal-catalytic therapy has emerged as a promising strategy for antitumor treatment. Extensive research has focused on optimizing the catalytic activity and photothermal conversion performance of nanozymes through size, morphology, and surface property regulations. However, the biological effects of nanozymes, such as cellular uptake and cytotoxicity, resulting from their physicochemical properties, remain largely unexplored. In this study, two types of polydopamine/platinum (PDA@Pt) nanozymes, flower-like (FPDA@Pt) and mesoporous spherical-like (MPDA@Pt), to comprehensively compare their enzyme-mimicking activity, photothermal conversion capacity, and antitumor efficiency are designed. These findings revealed that FPDA@Pt exhibited superior peroxidase-like activity and higher photothermal conversion efficiency compared to MPDA@Pt. This led to enhanced production of reactive oxygen species (ROS) and increased heat generation at tumor sites. Importantly, it is observed thatthe flower-like structure of FPDA@Pt facilitated enhanced cellular uptake, leading to an increased accumulation of nanozymes within tumor cells. Furthermore, the light irradiation on tumors also triggered a series of anti-tumor immune responses, further enhancing the therapeutic efficacy. This work provides a possible design orientation for nanozyme-based photothermal-catalytic tumor therapy, highlighting the importance of considering the physicochemical properties of nanozymes to optimize their therapeutic potential in antitumor strategies.

Perspectives on Protein-Nanoparticle Interactions at the In Vivo Level

The distinct features of nanoparticles have provided a vast opportunity of developing new diagnosis and therapy strategies for miscellaneous diseases. Although a few nanomedicines are available in the market or in the translation stage, many important issues are still unsolved. When entering the body, nanomaterials will be quickly coated by proteins from their surroundings, forming a corona on their surface, the so-called protein corona. Studies have shown that the protein corona has many important biological implications, particularly at the in vivo level. For example, they can promote the immune system to rapidly clear these outer materials and prevent nanoparticles from playing their designed role in therapy. In this Perspective, the available techniques for characterizing protein-nanoparticle interactions are critically summarized. Effects of nanoparticle properties and environmental factors on protein corona formation, which can further regulate the in vivo fate of nanoparticles, are highlighted and discussed. Moreover, recent progress on the biomedical application of protein corona-engineered nanoparticles is introduced, and future directions for this important yet challenging research area are also briefly discussed.

Synthesis of Taxifolin-Loaded Polydopamine for Chemo-Photothermal-Synergistic Therapy of Ovarian Cancer

Chemotherapy is a well-established method for treating cancer, but it has limited effectiveness due to its high dosage and harmful side effects. To address this issue, researchers have explored the use of photothermal agent nanoparticles as carriers for precise drug release in vivo. In this study, three different sizes of polydopamine nanoparticles (PDA-1, PDA-2, and PDA-3) were synthesized and evaluated. PDA-2 was selected for its optimal size, encapsulation rate, and drug loading rate. The release of the drug from PDA-2@TAX was tested at different pH and NIR laser irradiation levels. The results showed that PDA-2@TAX released more readily in an acidic environment and exhibited a high photothermal conversion efficiency when exposed to an 808 nm laser. In vitro experiments on ovarian cancer cells demonstrated that PDA-2@TAX effectively inhibited cell proliferation, highlighting its potential for synergistic chemotherapy-photothermal treatment.

Research progress of organic photothermal agents delivery and synergistic therapy systems

Cancer is currently one of the leading causes of mortality worldwide. Due to the inevitable shortcomings of conventional treatments, photothermal therapy (PTT) has attracted great attention as an emerging and non-invasive cancer treatment method. Photothermal agents (PTAs) is a necessary component of PTT to play its role. It accumulates at the tumor site through appropriate methods and converts the absorbed light energy into heat energy effectively under near-infrared light irradiation, thus increasing the temperature of the tumor area and facilitating ablation of the tumor cells. Compared to inorganic photothermal agents, which have limitations such as non-degradability and potential long-term toxicity in vivo, organic photothermal agents exhibit excellent biocompatibility and biodegradability, thus showing promising prospects for the application of PTT in cancer treatment. And these organic photothermal agents can also be engineered into nanoparticles to improve their water solubility, extend their circulation time in vivo, and specifically target tumors. Moreover, further combination of PTT with other treatment methods can effectively enhance the efficacy of cancer treatment and alleviate the side effects associated with single treatments. This article briefly introduces several common types of organic photothermal agents and their nanoparticles, and reviews the applications of PTT based on organic photothermal agents in combination with chemotherapy, photodynamic therapy, chemodynamic therapy, immunotherapy, and multimodal combination therapy for tumor treatment, which expands the ideas and methods in the field of tumor treatment.

Self-driven bioactive hybrids co-deliver doxorubicin and indocyanine green nanoparticles for chemo/photothermal therapy of breast cancer

Breast cancer is characterized by insidious onset, rapid progression, easy recurrence, and metastasis. Conventional monotherapies are usually ineffective due to insufficient drug delivery. Therefore, the combination of multimodal therapy with tumor microenvironment (TME)-responsive nanoplatforms is increasingly being considered for the targeted treatment of breast cancer. We synthesized bioactive hybrid nanoparticles for synergistic chemotherapy and photothermal therapy. Briefly, doxorubicin (DOX) and indocyanine green (ICG)-loaded nanoparticles (DI) of average particle size 113.58 ± 2.14 nm were synthesized, and their surface were modified with polydopamine (PDA) and attached to the anaerobic probiotic Bifidobacterium infantis (Bif). The bioactive Bif@DIP hybrid showed good photothermal conversion efficiency of about 38.04%. In addition, the self-driving ability of Bif allowed targeted delivery of the PDA-coated DI nanoparticles (DIP) to the hypoxic regions of the tumor. The low pH and high GSH levels in the TME stimulated the controlled release of DOX and ICG from the Bif@DIP hybrid, which then triggered apoptosis of tumor cells and induced immunogenic cell death (ICD), resulting in effective and sustained anti-tumor effect with minimum systemic toxicity. Thus, the self-driven Bif@DIP hybrid is a promising nanodrug for the targeted chemotherapy and photothermal therapy against solid cancers.

Target Design of Multinary Metal-Organic Frameworks for Near-Infrared Imaging and Chemodynamic Therapy

Imaging-guided chemodynamic therapy is widely considered a promising modality for personalized and precision cancer treatment. Combining both imaging and chemodynamic functions in one system conventionally relies on the hybrid materials approach. However, the heterogeneous, ill-defined, and dissociative/disintegrative nature of the composites tends to complicate their action proceedings in biological environments and thus makes the treatment imprecise and ineffective. Herein, a strategy to employ two kinds of inorganic units with different functions─reactive oxygen species generation and characteristic emission─has achieved two single-crystalline metal-organic frameworks (MOFs), demonstrating the competency of reticular chemistry in creating multifunctional materials with atomic precision. The multinary MOFs could not only catalyze the transformation from H2O2 to hydroxyl radicals by utilizing the redox-active Cu-based units but also emit characteristic tissue-penetrating near-infrared luminescence brought by the Yb4 clusters in the scaffolds. Dual functions of MOF nanoparticles are further evidenced by pronounced cell imaging signals, elevated intracellular reactive oxygen species levels, significant cell apoptosis, and reduced cell viabilities when they are taken up by the HeLa cells. In vivo NIR imaging is demonstrated after the MOF nanoparticles are further functionalized. The independent yet interconnected modules in the intact MOFs could operate concurrently at the same cellular site, achieving a high spatiotemporal consistency. Overall, our work suggests a new method to effectively accommodate both imaging and therapy functions in one well-defined material for precise treatment.

Polydopamine-containing nano-systems for cancer multi-mode diagnoses and therapies: A review

Polydopamine (PDA) has fascinating properties such as inherent biocompatibility, simple preparation, strong near-infrared absorption, high photothermal conversion efficiency, and strong metal ion chelation, which have catalyzed extensive research in PDA-containing multifunctional nano-systems particularly for biomedical applications. Thus, it is imperative to overview synthetic strategies of various PDA-containing nanoparticles (NPs) for state-of-the-art cancer multi-mode diagnoses and therapies applications, and offer a timely and comprehensive summary. In this review, we will focus on the synthetic approaches of PDA NPs, and summarize the construction strategies of PDA-containing NPs with different structure forms. Additionally, the application of PDA-containing NPs in bioimaging such as photoacoustic imaging, fluorescence imaging, magnetic resonance imaging and other imaging modalities will be reviewed. We will especially offer an overview of their therapeutic applications in tumor chemotherapy, photothermal therapy, photodynamic therapy, photocatalytic therapy, sonodynamic therapy, radionuclide therapy, gene therapy, immunotherapy and combination therapy. At the end, the current trends, limitations and future prospects of PDA-containing nano-systems will be discussed. This review aims to provide guidelines for new scientists in the field of how to design PDA-containing NPs and what has been achieved in this area, while offering comprehensive insights into the potential of PDA-containing nano-systems used in cancer diagnosis and treatment.

Recent Progress of Photothermal Therapy Based on Conjugated Nanomaterials in Combating Microbial Infections

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to the choice of photothermal agent. Conjugated nanomaterials are potential candidates for photothermal agents because of their easy modification, excellent photothermal conversion efficiency, good photostability, and biodegradability. In this paper, the application of photothermal agents based on conjugated nanomaterials in photothermal antimicrobial treatment is reviewed, including conjugated small molecules, conjugated oligomers, conjugated polymers, and pseudo-conjugated polymers. At the same time, the application of conjugated nanomaterials in the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is briefly introduced. Finally, the research status, limitations, and prospects of photothermal therapy using conjugated nanomaterials as photothermal agents are discussed.

Polydopamine nanoparticles coated with a metal-polyphenol network for enhanced photothermal/chemodynamic cancer combination therapy

Polydopamine nanoparticles (PDA NPs) are commonly used for photothermal therapy (PTT) of cancer because of their good biocompatibility and photothermal conversion capability. However, it is difficult to achieve a good tumor inhibition effect with a single PTT of PDA. Therefore, in this work, we prepared a combined anticancer nanosystem for enhanced chemodynamic therapy (CDT)/PTT by coating PDAs with an (-)-epigallocatechin gallate (EGCG)/iron (Fe) metal-polyphenol network (MPN). The MPN shell of this nanosystem named EGCG@PDA is degraded by the weakly acidic environment intracellular, releasing EGCG and Fe³⁺. EGCG inhibits the expression of heat shock proteins (HSPs) in cancer cells, thus eliminating their thermal protection against cancer cells for enhanced PTT. Meanwhile, the reductive EGCG can also reduce Fe³⁺ to Fe²⁺, to catalyze the decomposition of overexpressed hydrogen peroxide (H₂O₂) in cancer cells to generate strong oxidative hydroxyl radicals (OH), i.e., catalyzing the Fenton reaction, for CDT. After the Fenton reaction, the re-oxidized Fe ions can be reduced again by EGCG and reused to catalyze the Fenton reaction, which can achieve enhanced CDT. Both in vitro and in vivo studies have shown that EGCG@PDA has low dark toxicity and good anticancer effects. It is expected to be used for precision cancer therapy.

Fabrication and properties of multi-functional polydopamine coated Cu/F-codoped hydroxyapatite hollow microspheres as drug carriers

Due to its excellent bone conductivity and drug adsorption as well as pH-responsive drug release property, hydroxyapatite (HAp) is widely used as a drug carrier in bone repair field. Here, we report for the first time a novel multi-functional polydopamine (PDA) coated Cu/F-codoped HAp (Cu/F-HAp-PDA) hollow microspheres. Both Cu²⁺ and F^- were successfully doped into the lattice of HAp and uniformly distributed in the shell of hollow microspheres through a one-step hydrothermal synthesis. Then PDA was coated homogeneously on the outer layer of Cu/F-HAp hollow microspheres. Both Cu/F-HAp and Cu/F-HAp-PDA samples displayed high drug loading efficiency and pH responsive drug release behavior. Moreover, the obtained Cu/F-HAp-PDA hollow microspheres exhibited excellent photothermal conversion efficiency and photothermal stability. The molecular dynamics simulations showed that PDA and HAp can form mutual binding mainly through Ca-O bonding, while doxorubicin (DOX) is mainly bound to PDA molecules through hydrogen bonding and π-π stacking interaction.

Melanin-like nanoparticles: advances in surface modification and tumour photothermal therapy

Currently, tumor treatments are characterized by intelligence, diversity and personalization, but the therapeutic reagents used are often limited in clinical efficacy due to problems with water solubility, targeting, stability and multidrug resistance. To remedy these shortcomings, the application of multifunctional nanotechnology in the biomedical field has been widely studied. Synthetic melanin nanoparticles (MNPs) surfaces which contain highly reactive chemical groups such as carboxyl, hydroxyl and amine groups, can be used as a reaction platform on which to graft different functional components. In addition, MNPs easily adhere to substrate surface, and serve as a secondary reaction platform to modify it. The multifunctionality and intrinsic biocompatibility make melanin-like nanoparticles promising as a multifunctional and powerful nanoplatform for oncological applications. This paper first reviews the preparation methods, polymerization mechanisms and physicochemical properties of melanin including natural melanin and chemically synthesized melanin to guide scholars in MNP-based design. Then, recent advances in MNPs especially synthetic polydopamine (PDA) melanin for various medical oncological applications are systematically and thoroughly described, mainly focusing on bioimaging, photothermal therapy (PTT), and drug delivery for tumor therapy. Finally, based on the investigated literature, the current challenges and future directions for clinical translation are reasonably discussed, focusing on the innovative design of MNPs and further elucidation of pharmacokinetics. This paper is a timely and comprehensive and detailed study of the progress of MNPs in tumor therapy, especially PTT, and provides ideas for the design of personalized and customizable oncology nanomedicines to address the heterogeneity of the tumor microenvironment.

Recent advances in near-infrared-II hollow nanoplatforms for photothermal-based cancer treatment

Near-infrared-II (NIR-II, 1000–1700 nm) light-triggered photothermal therapy (PTT) has been regarded as a promising candidate for cancer treatment, but PTT alone often fails to achieve satisfactory curative outcomes. Hollow nanoplatforms prove to be attractive in the biomedical field owing to the merits including good biocompatibility, intrinsic physical-chemical nature and unique hollow structures, etc. On one hand, hollow nanoplatforms themselves can be NIR-II photothermal agents (PTAs), the cavities of which are able to carry diverse therapeutic units to realize multi-modal therapies. On the other hand, NIR-II PTAs are capable of decorating on the surface to combine with the functions of components encapsulated inside the hollow nanoplatforms for synergistic cancer treatment. Notably, PTAs generally can serve as good photoacoustic imaging (PAI) contrast agents (CAs), which means such kind of hollow nanoplatforms are also expected to be multifunctional all-in-one nanotheranostics. In this review, the recent advances of NIR-II hollow nanoplatforms for single-modal PTT, dual-modal PTT/photodynamic therapy (PDT), PTT/chemotherapy, PTT/catalytic therapy and PTT/gas therapy as well as multi-modal PTT/chemodynamic therapy (CDT)/chemotherapy, PTT/chemo/gene therapy and PTT/PDT/CDT/starvation therapy (ST)/immunotherapy are summarized for the first time. Before these, the typical synthetic strategies for hollow structures are presented, and lastly, potential challenges and perspectives related to these novel paradigms for future research and clinical translation are discussed.

Non-covalent small molecule partnership for redox-active films: Beyond polydopamine technology

HYPOTHESIS

The possibility to use hexamethylenediamine (HMDA) to impart film forming ability to natural polymers including eumelanins and plant polyphenols endowed with biological activity and functional properties has been recently explored with the aim to broaden the potential of polydopamine (PDA)-based films overcoming their inherent limitations. 5,6-dihydroxyindole-2-carboxylic acid, its methyl ester (MeDHICA) and eumelanins thereof were shown to exhibit potent reducing activity.

EXPERIMENTS

MeDHICA and HMDA were reacted in aqueous buffer, pH 9.0 in the presence of different substrates to assess the film forming ability. The effect of different reaction parameters (pH, diamine chain length) on film formation was investigated. Voltammetric and AFM /SEM methods were applied for analysis of the film redox activity and morphology. HPLC, MALDI-MS and ¹HNMR were used for chemical characterization. The film reducing activity was evaluated in comparison with PDA by chemical assays and using UV stressed human immortalized keratinocytes (HaCat) cells model.

FINDINGS

Regular and homogeneous yellowish films were obtained with moderately hydrophobic properties. Film deposition was optimal at pH 9, and specifically induced by HMDA. The film consisted of HMDA and monomeric MeDHICA accompanied by dimers/small oligomers, but no detectable MeDHICA/HMDA covalent conjugation products. Spontaneous assembly of self-organized networks held together mainly by electrostatic interactions of MeDHICA in the anion form and HMDA as the dication is proposed as film deposition mechanism. The film displayed potent reducing properties and exerted significant protective effects from oxidative stress on HaCaT.

PDA-Based Drug Delivery Nanosystems: A Potential Approach for Glioma Treatment

Glioma is characterized by high mortality and low postoperative survival. Despite the availability of various therapeutic approaches and molecular typing, the treatment failure rate and the recurrence rate of glioma remain high. Given the limitations of existing therapeutic tools, nanotechnology has emerged as an alternative treatment option. Nanoparticles, such as polydopamine (PDA)-based nanoparticles, are embodied with reliable biodegradability, efficient drug loading rate, relatively low toxicity, considerable biocompatibility, excellent adhesion properties, precisely targeted delivery, and strong photothermal conversion properties. Therefore, they can further enhance the therapeutic effects in patients with glioma. Moreover, polydopamine contains pyrocatechol, amino and carboxyl groups, active double bonds, catechol, and other reactive groups that can react with biofunctional molecules containing amino, aldehyde, or sulfhydryl groups (main including, self-polymerization, non-covalent self-assembly, π-π stacking, electrostatic attraction interaction, chelation, coating and covalent co-assembly), which form a reversible dynamic covalent Schiff base bond that is extremely sensitive to pH values. Meanwhile, PDA has excellent adhesion capability that can be further functionally modified. Consequently, the aim of this review is to summarize the application of PDA-based NPs in glioma and to acquire insight into the therapeutic effect of the drug-loaded PDA-based nanocarriers (PDA NPs). A wealthy understanding and argument of these sides is anticipated to afford a better approach to develop more reasonable and valid PDA-based cancer nano-drug delivery systems. Finally, we discuss the expectation for the prospective application of PDA in this sphere and some individual viewpoints.

Recent advances in nanoparticle-based photothermal therapy for breast cancer

Breast cancer is one of the most common cancers among women that is associated with high mortality. Conventional treatments including surgery, radiotherapy, and chemotherapy, which are not effective enough and have disadvantages such as toxicity and damage to healthy cells. Photothermal therapy (PTT) of cancer cells has been took great attention by researchers in recent years due to the use of light radiation and heat generation at the tumor site, which thermal ablation is considered a minimally invasive method for the treatment of breast cancer. Nanotechnology has opened up a new perspective in the treatment of breast cancer using PTT method. Through NIR light absorption, researchers applied various nanostructures because of their specific nature of penetrating and targeting tumor tissue, increasing the effectiveness of PTT, and combining it with other treatments. If PTT is used with common cancer treatments, it can dramatically increase the effectiveness of treatment and reduce the side effects of other methods. PTT performance can also be improved by hybridizing at least two different nanomaterials. Nanoparticles that intensely absorb light and increase the efficiency of converting light into heat can specifically kill tumors through hyperthermia of cancer cells. One of the main reasons that have increased the efficiency of nanoparticles in PTT is their permeability and durability effect and they can accumulate in tumor tissue. Targeted PTT can be provided by incorporating specific ligands to target receptors expressed on the surface of cancer cells on nanoparticles. These nanoparticles can specifically target cancer cells by maintaining the surface area and increasing penetration. In this study, we briefly introduce the performance of light therapy, application of metal nanoparticles, polymer nanoparticles, carbon nanoparticles, and hybrid nanoparticles for use in PTT of breast cancer.

Biomimetic smart mesoporous carbon nanozyme as a dual-GSH depletion agent and O2 generator for enhanced photodynamic therapy

Photodynamic therapy (PDT) has been thriving in the theranostics of cancer in recent years. However, due to a series of problems such as high concentration of GSH and insufficient O₂ partial pressure in the tumor micro-environment, it is difficult to achieve the desired therapeutic effects with single PDT. Mesoporous carbon (MC-COOH) has been widely used in photothermal therapy (PTT) due to its high photothermal conversion efficiency and drug loading. In addition, we have discovered that MC-COOH owned high-efficiency glutathione oxidase-like activity for intracellular lasting GSH consumption. Hence, a smart mesoporous carbon nanozyme (CCM) was designed as a dual-GSH depletion agent and O₂ generator combined with PTT to overcome the dilemma of PDT. MnO₂-doped carbon nanozyme (MC-Mn) was developed as the photothermal vehicles for the efficient loading of photosensitizer (Ce6). Subsequently, 4T1 membrane-coated nanozyme (Ce6/CCM) was constructed to achieve homologous targeting capability. The carbon nanozyme owned the sustained dual-GSH depletion function through MC-COOH and MnO₂, which greatly destroyed the antioxidant system of the tumor. Meanwhile, MnO₂ could produce affluent O₂ in the presence of H₂O₂, thereby alleviating the hypoxic state of tumor tissues and further promoting the generation of ROS. In addition, the novel carbon nanozyme was designed as photoacoustic imaging (PAI) agent and magnetic resonance imaging (MRI) contrast for real-time imaging during tumor therapy. In summary, this work showed that the biomimetic carbon nanozyme could be used as dual-GSH depletion agent and O₂ generator for dual-mode imaging-guided PTT-PDT. STATEMENT OF SIGNIFICANCE: - MC-COOH with highly efficient GSH-OXD activity was first discovered and applied in PDT. - MnO₂ acted as an O₂ generator and GSH depletion agent to enhance PDT. - The tumor-targeting ability of the nanozyme was improved by cell membrane camouflage. - CCM nanozyme possesses both PAI and MRI dual-mode imaging modalities to guide PDT/PTT.

Photothermal interference urease-powered polydopamine nanomotor for enhanced propulsion and synergistic therapy

Enzyme-powered nanomotors with active motion have opened a new door in design of biocompatible drug delivery systems for cancer treatment. However, the movement of them still faces huge challenges due to the viscous physiological environment. To address this issue, we developed a photothermal interference (PTI) urease-modified polydopamine (PDA) nanomotor (PDA@HSA@Ur) for deeper-penetration of doxorubicin (DOX) through improved motion. The urease-powered nanomotors can generate self-propulsion via catalyzing decomposition of biocompatible urea into carbon dioxide and ammonia through a self-diffusiophoretic. Meanwhile, when exposed to near-infrared (NIR) laser, the increased temperature of tumors microenvironment from nanomotors can not only induce tumor cell apoptosis but also enhance the biocatalytic activity of urease to improve the motion of nanomotors. Compared to the nanomotors propelled only by urea, PTI nanomotors realize highly effective self-propulsion with improved cellular uptake in vitro. Furthermore, PTI nanomotors display an enhanced anticancer efficiency owing to synergistic photothermal and chemotherapy effect. The PTI reported in this manuscript is the first to provide a thermally assisted method for highly efficient cancer treatment with urease-powered nanomotors in a complex physiological environment through enhanced motion and synergistic therapy.