Polydopamine-Derivated Hierarchical Nanoplatforms for Efficient Dual-Modal Imaging-Guided Combination in Vivo Cancer Therapy

Hierarchical magneto-colorimetric labels for immediate lateral flow immunoassay of chlorothalonil residues

Quantitative detection of pesticide residues in food and environmental samples using an improved lateral flow immunoassay (LFIA) is of considerable importance for real-time analysis. This paper proposes a highly sensitive LFIA platform based on a hierarchical magneto-colorimetric compact. This compact serves as both the target magnetic enrichment substrate and a photosensitive label. Initially, a large porous dendritic silica template is prepared and doped with superparamagnetic ferric oxide nanoparticles (Fe3O4 NPs) and colloidal gold nanoparticles (AuNPs) at high densities within its vertical channels. The sequential assembly of central-radial channels allow for the three-dimensional integration of these two components, enabling independent control of their discrete functions without mutual interference. Following alkyl organosilicon encapsulation and silica sealing, the composite spheres are then applied in LFIA to detect chlorothalonil residues. Fe3O4 NPs enhance the binding efficiency to target analytes, while AuNPs amplify the signal, leveraging their high loading densities and robust optical properties. The developed LFIA platform exhibited a detection limit of 0.34 ng/mL for chlorothalonil and a linear range of 0.0085-824 ng/mL. The recoveries varied between 85.1 % and 103.1 %, and the relative standard deviations were 1.25%-8.84 %. This LFIA approach demonstrates high sensitivity, specificity, reproducibility and flexible detection modes, making it highly suitable for the on-site monitoring of pesticide residues.

Reconstruction of TNF-α with specific isoelectric point released from SPIONs basing on variable charge to enhance pH-sensitive controlled-release

The clinical application of tumor necrosis factor-α (TNF-α) is limited by its short half-life, subeffective concentration in the targeted area and severe systemic toxicity. In this study, the recombinant polypeptide S4-TNF-α was constructed and coupled with chitosan-modified superparamagnetic iron oxide nanoparticles (S4-TNF-α-SPIONs) to achieve pH-sensitive controlled release and active tumor targeting activity. The isoelectric point (pI) of S4-TNF-α was reconstructed to approach the pH of the tumor microenvironment. The negative-charge S4-TNF-α was adsorbed to chitosan-modified superparamagnetic iron oxide nanoparticles (CS-SPIONs) with a positive charge through electrostatic adsorption at physiological pH. The acidic tumor microenvironment endowed S4-TNF-α with a zero charge, which accelerated S4-TNF-α release from CS-SPIONs. Our studies showed that S4-TNF-α-SPIONs displayed an ideal pH-sensitive controlled release capacity and improved antitumor effects. Our study presents a novel approach to enhance the pH-sensitive controlled-release of genetically engineered drugs by adjusting their pI to match the pH of the tumor microenvironment.

NIR-responsive porous gold nanorod dispersed in a 3D gelatin scaffold for stimulus-responsive drug release and synergistic therapy

Biodegradable porous nanomaterials have emerged as a promising avenue for tumor drug delivery owing to their capacity to encapsulate large quantities of drugs and their compatibility with biological systems.

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.

Hollow-polydopamine-nanocarrier-based near-infrared-light/pH-responsive drug delivery system for diffuse alveolar hemorrhage treatment

Introduction: Diffuse alveolar hemorrhage (DAH) is a serious complication caused by systemic lupus erythematosus (SLE). Tissue damage and changes in immune response are all associated with excessive free radical production. Therefore, removing excess reactive oxygen species are considered a feasible scheme for diffuse alveolar hemorrhage treatment. Cyclophosphamide is often used as the main therapeutic drug in clinics. However, CTX carries a high risk of dose-increasing toxicity, treatment intolerance, and high recurrence rate. The combination of therapeutic drugs and functional nanocarriers may provide an effective solution. PDA is rich in phenolic groups, which can remove the reactive oxygen species generated in inflammatory reactions, and can serve as excellent free radical scavengers. Methods: We developed a hollow polydopamine (HPDA) nanocarrier loaded with CTX by ionization to prepare the novel nanoplatform, CTX@HPDA, for DAH treatment. The monodisperse silica nanoparticles were acquired by reference to the typical Stober method. PDA was coated on the surface of SiO₂ by oxidation self-polymerization method to obtain SiO₂@PDA NPs. Then, HPDA NPs were obtained by HF etching. Then HPDA was loaded with CTX by ionization to prepare CTX@HPDA. Then we tested the photothermal effect, animal model therapeutics effect, and biosafety of CTX@HPDA. Results: Material tests showed that the CTX@ HPDA nanoplatform had a uniform diameter and could release CTX in acidic environments. The vitro experiments demonstrated that CTX@HPDA has good photothermal conversion ability and photothermal stability. Animal experiments demonstrated that the CTX@HPDA nanoplatform had good biocompatibility. The nanoplatform can dissociate in acidic SLE environment and trigger CTX release through photothermal conversion. Combining HPDA, which scavenges oxygen free radicals, and CTX, which has immunosuppressive effect, can treat pulmonary hemorrhage in SLE. Micro-CT can be used to continuously analyze DAH severity and lung changes in mice after treatment. The pulmonary exudation in the various treatment groups improved to varying degrees. Discussion: In this study, we report a photothermal/PH-triggered nanocarrier (CTX@HPDA) for the precise treatment of SLE-DAH. CTX@HPDA is a simple and efficient nanocarrier system for DAH therapy. This work provides valuable insights into SLE treatment.

The sound of drug delivery: Optoacoustic imaging in pharmacology

Optoacoustic (photoacoustic) imaging offers unique opportunities for visualizing biological function in vivo by achieving high-resolution images of optical contrast much deeper than any other optical technique. The method detects ultrasound waves that are generated inside tissue by thermo-elastic expansion, i.e., the conversion of light absorption by tissue structures to ultrasound when the tissue is illuminated by the light of varying intensity. Listening instead of looking to light offers the major advantage of image formation with a resolution that obeys ultrasonic diffraction and not photon diffusion laws. While the technique has been widely used to explore contrast from endogenous photo-absorbing molecules, such as hemoglobin or melanin, the use of exogenous agents can extend applications to a larger range of biological and possible clinical applications, such as image-guided surgery, disease monitoring, and the evaluation of drug delivery, biodistribution, and kinetics. This review summarizes recent developments in optoacoustic agents, and highlights new functions visualized and potent pharmacology applications enabled with the use of external contrast agents.

Recent Advances in Reactive Oxygen Species (ROS)-Responsive Polyfunctional Nanosystems 3.0 for the Treatment of Osteoarthritis

Osteoarthritis (OA) is an inflammatory and degenerative joint disease with severe effects on individuals, society, and the economy that affects millions of elderly people around the world. To date, there are no effective treatments for OA; however, there are some treatments that slow or prevent its progression. Polyfunctional nanosystems have many advantages, such as controlled release, targeted therapy and high loading rate, and have been widely used in OA treatment. Previous mechanistic studies have revealed that inflammation and ROS are interrelated, and a large number of studies have demonstrated that ROS play an important role in different types of OA development. In this review article, we summarize third-generation ROS-sensitive nanomaterials that scavenge excessive ROS from chondrocytes and osteoclasts in vivo. We only focus on polymer-based nanoparticles (NPs) and do not review the effects of drug-loaded or heavy metal NPs. Mounting evidence suggests that polyfunctional nanosystems will be a promising therapeutic strategy in OA therapy due to their unique characteristics of being sensitive to changes in the internal environment.

Cytocompatibility of pH-sensitive, chitosan-coated Fe3O4 nanoparticles in gynecological cells

Nanoparticles that contact human cells without damaging basic human tissues are becoming more widely used in medicine. Efficient delivery to the intracellular target cell or compartment through the cell membrane must be achieved with minimal cytotoxicity to healthy cells. Fe₃O₄ nanoparticles have been widely used in biomedical research for their magnetic, non-toxic, and biocompatible properties. However, the effects of Fe₃O₄ nanoparticles coated with chitosan (CS) on gynecological cells are unclear. In this study, the Fe₃O₄ nanoparticles were coated with CS to enhance their cytocompatibility and dispersion in water. These CS-Fe₃O₄ nanoparticles were taken up by gynecological cells and did not affect cell viability in vitro. They have greater cytocompatibility in acidic environments than normal Fe₃O₄ nanoparticles and have the potential for drug delivery into gynecological cells.

Numerical simulation of superparamagnetic nanoparticle motion in blood vessels for magnetic drug delivery

A numerical model is developed for the motion of superparamagnetic nanoparticles in a non-Newtonian blood flow under the influence of a magnetic field. The rheological properties of blood are modeled by the Carreau flow and viscosity, and the stochastic effects of Brownian motion and red blood cell collisions are considered. The model is validated with existing data and good agreement with experimental results is shown. The effectiveness of magnetic drug delivery in various blood vessels is assessed and found to be most successful in arterioles and capillaries. A range of magnetic field strengths are modeled using equations for both a bar magnet and a point dipole: it is shown that the bar magnet is effective at capturing nanoparticles in limited cases, while the point dipole is highly effective across a range of conditions. A parameter study is conducted to show the effects of changing the dipole moment, the distance from the magnet to the blood vessel, and the initial release point of the nanoparticles. The distance from the magnet to the blood vessel is shown to play a significant role in determining nanoparticle capture rate. The optimal initial release position is found to be located within the tumor radius in capillaries and arterioles to prevent rapid diffusion to the edges of the blood vessel prior to arriving at the tumor and near the edge of the magnet when a bar magnet is used.

Engineering Bio-MOF/polydopamine as a biocompatible targeted theranostic system for synergistic multi-drug chemo-photothermal therapy

In this study, a biodegradable multifunctional photothermal drug delivery nanoparticles (MPH NPs) using curcumin (Cur) as the ligand coated with hyaluronic acid (HA) was successfully prepared, which could simultaneously deliver Cur and doxorubicin hydrochloride (DOX·HCl) to overcome the common drug resistance in cancer cells. Polydopamine (PDA) as a protective shell prevents premature degradation of Cur in physiological environment and enables it to play effective medicinal value. MPH NPs can specifically recognize CD44 receptors on the surface of cancer cells for tumor targeting, with the damage of the partially released DOX to the superficial tumor cells, and then the positively charged Cur released may gradually penetrate into the cells through electron interaction to improve the problem of low permeability. In vitro cell experiments showed that hydrophobic/hydrophilic drugs co-loaded MPDH (MPH loaded with DOX·HCl) could enter the cancer cells through the endocytosis mediated by clathrin / caveolin, and the inhibition rate of MPDH on HeLa cells reached 79.28 % irradiation under 808 nm laser. MPH were composed of safe materials that have been proven to be biodegradable in human body, which avoided the disadvantages that NPs were difficult to discharge and caused damage to normal organs during long-term use.

Micro/Nanosystems for Magnetic Targeted Delivery of Bioagents

Targeted delivery of pharmaceuticals is promising for efficient disease treatment and reduction in adverse effects. Nano or microstructured magnetic materials with strong magnetic momentum can be noninvasively controlled via magnetic forces within living beings. These magnetic carriers open perspectives in controlling the delivery of different types of bioagents in humans, including small molecules, nucleic acids, and cells. In the present review, we describe different types of magnetic carriers that can serve as drug delivery platforms, and we show different ways to apply them to magnetic targeted delivery of bioagents. We discuss the magnetic guidance of nano/microsystems or labeled cells upon injection into the systemic circulation or in the tissue; we then highlight emergent applications in tissue engineering, and finally, we show how magnetic targeting can integrate with imaging technologies that serve to assist drug delivery.

Utilization of metal or non-metal-based functional materials as efficient composites in cancer therapies

There has been great progress in cancer treatment through traditional approaches, even though some of them are still trapped in relative complications such as certain side effects and prospective chances of full recovery. As a conventional method, the immunotherapy approach is regarded as an effective approach to cure cancer. It is mainly promoted by immune checkpoint blocking and adoptive cell therapy, which can utilize the human immune system to attack tumor cells and make them necrose completely or stop proliferating cancer cells. Currently however, immunotherapy shows limited success due to the limitation of real applicable cases of targeted tumor environments and immune systems. Considering the urgent need to construct suitable strategies towards cancer therapy, metallic materials can be used as delivery systems for immunotherapeutic agents in the human body. Metallic materials exhibit a high degree of specificity, effectiveness, diagnostic ability, imaging ability and therapeutic effects with different biomolecules or polymers, which is an effective option for cancer treatment. In addition, these modified metallic materials contain immune-modulators, which can activate immune cells to regulate tumor microenvironments and enhance anti-cancer immunity. Additionally, they can be used as adjuvants with immunomodulatory activities, or as carriers for molecular transport to specific targets, which results in the loading of specific ligands to facilitate specific uptake. Here, we provide an overview of the different types of metallic materials used as efficient composites in cancer immunotherapy. We elaborate on the advancements using metallic materials with functional agents as effective composites in synergistic cancer treatment. Some nonmetallic functional composites also appear as a common phenomenon. Ascribed to the design of the composites themselves, the materials' surface structural characteristics are introduced as the drug-loading substrate. The physical and chemical properties of the functional materials emphasize that further research is required to fully characterize their mechanism, showing appropriate relevance for material toxicology and biomedical applications.

Single and Multiple Stimuli-Responsive Polymer Particles for Controlled Drug Delivery

Polymers that can change their properties in response to an external or internal stimulus have become an interesting platform for drug delivery systems. Polymeric nanoparticles can be used to decrease the toxicity of drugs, improve the circulation of hydrophobic drugs, and increase a drug’s efficacy. Furthermore, polymers that are sensitive to specific stimuli can be used to achieve controlled release of drugs into specific areas of the body. This review discusses the different stimuli that can be used for controlled drug delivery based on internal and external stimuli. Internal stimuli have been defined as events that evoke changes in different characteristics, inside the body, such as changes in pH, redox potential, and temperature. External stimuli have been defined as the use of an external source such as light and ultrasound to implement such changes. Special attention has been paid to the particular chemical structures that need to be incorporated into polymers to achieve the desired stimuli response. A current trend in this field is the incorporation of several stimuli in a single polymer to achieve higher specificity. Therefore, to access the most recent advances in stimuli-responsive polymers, the focus of this review is to combine several stimuli. The combination of different stimuli is discussed along with the chemical structures that can produce it.

Recent advances and trends in nanoparticles based photothermal and photodynamic therapy

Light-mediated therapies, including photodynamic therapy (PDT) and photothermal therapy (PTT) have been exploited as minimally invasive techniques for ablation of various tumors., Both modalities may eradicate tumors with minimal side effects to normal tissues and organs. Moreover, developments of light-mediated approaches using nanoparticles (NPs) and photosensitizer (PS) as diagnostic and therapeutic agents may have a crucial role in achieving successful cancer treatment. In recent years, novel nanoplatforms and strategies have been investigated to boost the therapeutic effect.. In this regard, gold, iron oxide, graphene oxide nanoparticles and hybrid nanocomposites have attracted attention.. Moreover, the combination of these materials with PS, in the form of hybrid NPs, reduces in vitro and in vivo normal tissue cytotoxicity, improves their solubility property in the biological environment and enhances the therapeutic effects. In this review, we look into the basic principles of PTT and PDT with their strengths and limitations to treat cancers. We also will discuss light-based nanoparticles and their PTT and PDT applications in the preclinical and clinical translation. Also, recent advances and trends in this field will be discussed along with the clinical challenges of PTT and PDT.

Biodegradable Hollow Polydopamine@manganese Dioxide as an Oxygen Self-Supplied Nanoplatform for Boosting Chemo-photodynamic Cancer Therapy

Photodynamic therapy (PDT) has attracted extensive attention in the clinical treatment of malignant tumor. However, the acidic and hypoxic conditions of the tumor microenvironment (TME) limit the further application of PDT in the clinic. Herein, we fabricate a new nanoplatform─HPDA@MnO₂@Ce6/DOX@PEG-RGD (HPMRCD)─by means of coating hollow polydopamine nanoparticles (HPDA) with manganese dioxide (MnO₂), which is modified by cyclic RGD functionalized poly(ethylene glycol) (PEG) and further co-loaded with a photosensitizer, Chlorin e6 (Ce6), and a chemotherapy drug, doxorubicin (DOX). This nanoplatform could be enriched in tumor tissues, then instantly dissociated under an acidic and H₂O₂-rich TME. The dual-responsive release of Mn²⁺ ions and oxygen (O₂) can relieve tumor hypoxia, which can be used as a magnetic resonance contrast agent and the latter can enhance the PDT effect. Furthermore, the degradation of HPMRCD leads to an efficient loaded therapeutic molecule release, thus yielding a potential therapy to enhance tumor suppression by adopting the combined chemo-photodynamic therapy.

Trivalent Cations Detection of Magnetic-Sensitive Microcapsules by Controlled-Release Fluorescence Off-On Sensor

A pyrene-based derivative, 2-((pyrene-1-ylmethylene)amino)ethanol (PE) nanoparticle, was encapsulated via water-in-oil-in-water (W/O/W) double emulsion with the solvent evaporation method by one-pot reaction and utilized as a fluorescence turn-on sensor for detecting Fe³⁺, Cr³⁺, and Al³⁺ ions. Magnetic nanoparticles (MNPs) embedded in polycaprolactone (PCL) were used as the magnetic-sensitive polyelectrolyte microcapsule-triggered elements in the construction of the polymer matrix. The microcapsules were characterized by ultraviolet–visible (UV–Vis) and photoluminescence (PL) titrations, quantum yield (Φ_f) calculations, ¹H nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and superconducting quantum interference device magnetometry (SQUID) studies. This novel responsive release of the microcapsule fluorescence of the turn-on sensor for detecting trivalent cations was due to the compound PE and the MNPs being incorporated well within the whole system, and an effective thermal and kinetic energy transfer between the core and shell structure efficiently occurred in the externally oscillating magnetic field. The magnetic-sensitive fluorescence turn-on microcapsules show potential for effective metal ion sensing in environmental monitoring and even biomedical applications. Under the optimal controlled-release probe fluorescence conditions with high-frequency magnetic field treatment, the limit of detection (LOD) reached 1.574–2.860 μM and recoveries ranged from 94.7–99.4% for those metals in tap water.

Compact Magneto-Fluorescent Colloids by Hierarchical Assembly of Dual-Components in Radial Channels for Sensitive Point-of-Care Immunoassay

Exploring signal amplification strategies to enhance the sensitivity of lateral flow immunoassay (LFIA) is of great significance for point-of-care (POC) testing of low-concentrated targets in the field of in vitro diagnostics. Here, a highly-sensitive LFIA platform using compact and hierarchical magneto-fluorescent assemblies as both target-enrichment substrates and optical sensing labels is demonstrated. The large-pored dendritic templates are utilized for high-density incorporation of both superparamagnetic iron oxide nanoparticles (IOs) and quantum dots (QDs) within the vertical channels. The hierarchical structure is built via affinity-driven assembly of IOs and QDs from organic phase with silica surface and mercapto-organosilica intermediate layer, respectively. The sequential assembly with central-radial channels enables 3D loading of dual components and separately controlling of discrete functionalities. After the alkyl-organosilica encapsulation and silica sealing, the composite spheres exhibit high stabilities and compatibility with LFIA for procalcitonin (PCT) detection. With the assistance of liquid-phase antigen-capturing, magnetic enrichment, and fluorescence-signal amplification, a limit of detection of 0.031 ng mL^-1 for PCT is achieved with a linear range from 0.012 to 10 ng mL^-1 . The current LFIA is robust and validated for PCT detection in real serum, which holds great diagnostic significance for precise guidance of antibiotic therapy with POC manner.

An MRI-trackable therapeutic nanovaccine preventing cancer liver metastasis

Cancer vaccines consisting of tumor-associated antigens (TAAs) can initiate a powerful antitumor immune response through antigen-presenting cells, such as dendritic cells (DCs) and macrophages, and have shown great potential in cancer prevention and therapy. However, poor anticancer efficacy and an uncertain immunization process have hitherto limited the application of cancer vaccines. Herein, a multifunctional nanovaccine comprising ovalbumin (OVA), MnO₂, and polydopamine (OMPN) was prepared by a facile one-pot method. OMPN displayed excellent anticancer efficacy against an orthotopic melanoma and could also prevent liver metastasis in a tumor re-challenge mice model. Additionally, the migration behavior of DCs in the inguinal lymph node after vaccination was tracked by MRI contrasted with OMPN, indicating successful DC activation and immune response. The superior anticancer efficacy, especially the high efficiency against tumor metastasis, and the capability of tracking the immunization process make OMPN a very promising multifunctional nanovaccine for cancer therapy.

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.

Cartilage-targeting peptide-modified dual-drug delivery nanoplatform with NIR laser response for osteoarthritis therapy

Cartilage-targeting delivery of therapeutic agents is still an effective strategy for osteoarthritis (OA) therapy. Recently, scavenging for reactive oxygen species (ROS) and activating autophagy have been increasingly reported to treat OA effectively. In this study, we designed, for the first time, a dual-drug delivery system based on metal organic framework (MOF)-decorated mesoporous polydopamine (MPDA) which composed of rapamycin (Rap) loaded into the mesopores and bilirubin (Br) loaded onto the shell of MOF. The collagen II-targeting peptide (WYRGRL) was then conjugated on the surface of above nanocarrier to develop a cartilage-targeting dual-drug delivery nanoplatform (RB@MPMW). Our results indicated the sequential release of two agents from RB@MPMW could be achieved via near-infrared (NIR) laser irritation. Briefly, the rapid release of Br from the MOF shell exhibited excellent ROS scavenging ability and anti-apoptosis effects, however responsively reduced autophagy activity, to a certain extent. Meanwhile, following the NIR irradiation, Rap was rapidly released from MPDA core and further enhanced autophagy activation and chondrocyte protection. RB@MPMW continuously phosphorylated AMPK and further rescued mitochondrial energy metabolism of chondrocytes following IL-1β stimulation via activating SIRT1-PGC-1α signaling pathway. Additionally, the cartilage-targeting property of peptide-modified nanocarrier could be monitored via Magnetic Resonance (MR) and IVIS imaging. More significantly, RB@MPMW effectively delayed cartilage degeneration in ACLT rat model. Overall, our findings indicated that the as-prepared dual-drug delivery nanoplatform exerted potent anti-inflammation and anti-apoptotic effects, rescued energy metabolism of chondrocytes in vitro and prevented cartilage degeneration in vivo, which thereby showed positive performance for OA therapy.

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Collagen type II-targeting peptide and positive surface potential endow RB@MPMW with a fine cartilage affinity ability.

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RB@MPMW possess superb biological functions of scavenging free radicals and autophagy induction.

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RB@MPMW effectively promotes chondrocyte mitochondrial energy metabolism in the inflammatory microenvironment.

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RB@MPMW has a good MR imaging ability, which could monitor its therapeutic effects in vivo.

Stimuli-responsive polydopamine-based smart materials

This review provides in-depth insight into the structural engineering of PDA-based materials to enhance their responsive feature and the use of them in construction of PDA-based stimuli-responsive smart materials.

Metal-Containing Polydopamine Nanomaterials: Catalysis, Energy, and Theranostics

Polydopamine (PDA) is a major type of artificial melanin material with many interesting properties such as antioxidant activity, free-radical scavenging, high photothermal conversion efficiency, and strong metal-ion chelation. The high affinity of PDA to a wide range of metals/metal ions has offered a new class of functional metal-containing polydopamine (MPDA) nanomaterials with promising functions and extensive applications. Understanding and controlling the metal coordination environment is vital to achieve desirable functions for which such materials can be exploited. MPDA nanomaterials with metal/metal ions as the active functions are reviewed, including their synthesis and metal coordination environment and their applications in catalysis, batteries, solar cells, capacitors, medical imaging, cancer therapy, antifouling, and antibacterial coating. The current trends, limitations, and future directions of this area are also explored.

Nanoparticles modified by polydopamine: Working as "drug" carriers

Inspired by the mechanism of mussel adhesion, polydopamine (PDA), a versatile polymer for surface modification has been discovered. Owing to its unique properties like extraordinary adhesiveness, excellent biocompatibility, mild synthesis requirements, as well as distinctive drug loading approach, strong photothermal conversion capacity and reactive oxygen species (ROS) scavenging facility, various PDA-modified nanoparticles have been desired as drug carriers. These nanoparticles with diverse nanostructures are exploited in multifunctions, consisting of targeting, imaging, chemical treatment (CT), photodynamic therapy (PDT), photothermal therapy (PTT), tissue regeneration ability, therefore have attracted great attentions in plenty biomedical applications. Herein, recent progress of PDA-modified nanoparticle drug carriers in cancer therapy, antibiosis, prevention of inflammation, theranostics, vaccine delivery and adjuvant, tissue repair and implant materials are reviewed, including preparation of PDA-modified nanoparticle drug carriers with various nanostructures and their drug loading strategies, basic roles of PDA surface modification, etc. The advantages of PDA modification in overcoming the existing limitations of cancer therapy, antibiosis, tissue repair and the developing trends in the future of PDA-modified nanoparticle drug carriers are also discussed.

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Multifunctional PDA-modified drug systems are introduced in terms of classification, synthesis and drug loading strategies.

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Basic roles of PDA surface modification in the drug systems are discussed.

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Biomedical applications and unique advantages of the PDA-modified nanoparticle working as drug carriers are illustrated.

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Challenges and perspectives for future development are proposed.

NIR/Thermoresponsive Injectable Self-Healing Hydrogels Containing Polydopamine Nanoparticles for Efficient Synergistic Cancer Thermochemotherapy

Injectable and self-healing hydrogels with thermoresponsiveness as smart hydrogels displayed injectability, automatic healing, and phase and volume changes as well. Here, the thermoresponsive self-healing hydrogel was prepared via the formation of dynamic covalent enamine bonds between the amino groups in polyetherimide (PEI) and the acetoacetate groups in the four-armed star-shaped poly(2-(dimethylamino)ethyl methacrylate-co-2-hydroxyethyl methacrylate) modified with tert-butyl acetoacetate (t-BAA), SP(DMAEMA-co-HEMA-AA). After adding polydopamine nanoparticles (PDA NPs), the SP(DMAEMA-co-HEMA-AA)/PEI/PDA-NP nanocomposite hydrogel presented phase change and volume shrinkage under near-infrared (NIR) irradiation. The thermoresponsive nanocomposite hydrogel loaded with the anticancer drug doxorubicin (DOX) could be injected into the 4T1 tumor by intratumoral injection. After NIR laser irradiation, the temperature of the hydrogel increased because of the photothermal effect of PDA NPs inducing local hyperthermia. Because the hydrophilicity-hydrophobicity transition of the hydrogel occurred, DOX molecules were squeezed out from the hydrogel at temperatures higher than its lower critical solution temperature (LCST) and the tumor cells suffered from internal stress from the shrunk hydrogel. The injectable nanocomposite hydrogel not only demonstrated the synergism of highly efficient thermochemotherapy but also showed the function of improving drug utilization and precise treatment to reduce the side effects of drugs.

cRGD-Conjugated Fe3O4@PDA-DOX Multifunctional Nanocomposites for MRI and Antitumor Chemo-Photothermal Therapy

BACKGROUND

Photothermal therapy (PTT) has great potential in the clinical treatment of tumors. However, most photothermal materials are difficult to apply due to their insufficient photothermal conversion efficiencies (PCEs), poor photostabilities and short circulation times. Furthermore, tumor recurrence is likely to occur using PTT only. In the present study, we prepared cyclo (Arg-Gly-Asp-d-Phe-Cys) [c(RGD)] conjugated doxorubicin (DOX)-loaded Fe3O4@polydopamine (PDA) nanoparticles to develop a multifunctional-targeted nanocomplex for integrated tumor diagnosis and treatment.

MATERIALS AND METHODS

Cytotoxicity of Fe3O4@PDA-PEG-cRGD-DOX against HCT-116 cells was determined by cck-8 assay. Cellular uptake was measured by confocal laser scanning microscope (CLSM). Pharmacokinetic performance of DOX was evaluated to compare the differences between free DOX and DOX in nanocarrier. Performance in magnetic resonance imaging (MRI) and antitumor activity of complex nanoparticles were evaluated in tumor-bearing nude mice.

RESULTS

Fe3O4@PDA-PEG-cRGD-DOX has a particle size of 200-300 nm and a zeta potential of 22.7 mV. Further studies in vitro and in vivo demonstrated their excellent capacity to target tumor cells and promote drug internalization, and significantly higher cytotoxicity with respect to that seen in a control group was shown for the nanoparticles. In addition, they have good thermal stability, photothermal conversion efficiencies (PCEs) and pH responsiveness, releasing more DOX in a mildly acidic environment, which is very conducive to their chemotherapeutic effectiveness in the tumor microenvironment. Fe3O4@PDA-PEG-cRGD-DOX NPs were used in a subcutaneous xenograft tumor model of nude mouse HCT-116 cells showed clear signal contrast in T2-weighted images and effective anti-tumor chemo-photothermal therapy under NIR irradiation.

CONCLUSION

According to our results, Fe3O4@PDA-PEG-cRGD-DOX had a satisfactory antitumor effect on colon cancer in nude mice and could be further developed as a potential integrated platform for the diagnosis and treatment of cancer to improve its antitumor activity against colon cancer.

A polydopamine-based platform for anti-cancer drug delivery

Cancer is the second leading cause of death in the world with around 9.6 million deaths in 2018, approximately 70% of which occurred in the middle- and low-income countries; moreover, the economic impact of cancer is significant and escalating day by day. The total annual economic cost of cancer treatment in 2010 was estimated at approximately US$ 1.16 trillion. Researchers have explored cancer mitigation therapies such as chemo-thermal therapy, chemo-photothermal therapy and photodynamic-photothermal therapy. These combinational therapies facilitate better control on the tunability of the carrier for effectively diminishing cancer cells than individual therapies such as chemotherapy, photothermal therapy and targeted therapy. All these therapies come under novel drug delivery systems in which anti-cancer drugs attack the cancerous cells due to various stimuli (e.g. pH, thermal, UV, IR, acoustic and magnetic)-responsive properties of the anti-cancer drug carriers. Compared to conventional drug delivery systems, the novel drug delivery systems have several advantages such as targeted drug release, sustained and consistent blood levels within the therapeutic window, and decreased dosing frequency. Among the numerous polymeric carriers developed for drug delivery, polydopamine has been found to be more suitable as a carrier for these drug delivery functions due to its easy and cost-effective fabrication, excellent biocompatibility, multi-drug carrier capacity and stimuli sensitivity. Therefore, in this review, we have explored polydopamine-based carriers for anti-cancer drug delivery systems to mitigate cancer and simultaneously discussed basic synthesis routes for polydopamine.

Tumor Microenvironment-Responsive Nanoshuttles with Sodium Citrate Modification for Hierarchical Targeting and Improved Tumor Theranostics

Enhancement of permeability and the retention effect is one of the main pathways for the accumulation of nanomaterials in tumor sites, but poor cellular internalization and rapid clearance of nanomaterials always hamper the efficacy of imaging diagnosis and treatment. With the consideration of both high tumor accumulation and cellular internalization, positively charged nanomaterials can adhere to the tumor cell membrane by an electrostatic force, which is conducive to cellular internalization, but they are easily recognized and cleared during blood circulation. However, negatively charged nanomaterials show an enhanced stealth-like effect and possess a long blood circulation time, which is conducive to tumor accumulation. Therefore, in this work, on the basis of the shielding effect of citrate ions to positive charge and the protonation under an acidic tumor microenvironment, pH-sensitive sodium citrate-modified polyaniline nanoshuttles (NSs) with negative charge during blood circulation but positive charge in tumor sites are designed. With this hierarchical targeting strategy, the blood circulation half-life increases from 4.35 to 7.33 h, and the retention rate of NSs in tumors increases from 5.29 to 8.57% ID/g. Because the retention rate of NSs is increased, the magnetic resonance imaging resolution and signal intensity are significantly improved. A synergistic treatment of tumors is further achieved by means of photothermal therapy with laser irradiation and chemotherapy via heat-stimulated drug release.

Rod-shape MSN@MoS2 Nanoplatform for FL/MSOT/CT Imaging-Guided Photothermal and Photodynamic Therapy

Rod-shape nanoplatform have received tremendous attention owing to their enhanced ability for cell internalization and high capacity for drug loading. MoS2, widely used in electronic devices, electrocatalysis, sensor and energy-storage, has been studied as photothermal agents over the years. However, the efficacy of rod-shape MoS2 based photothermal agents for photothermal therapy has not been studied before. Here, a near-infrared (NIR) light-absorbing MoS2 nanosheets coated mesoporous silica nanorods with human serum albumin (HSA) modifying and Ce6 loading (MSNR@MoS2-HSA/Ce6) were constructed for combined photothermal and photodynamic therapy. Methods: The near-infrared (NIR) light was used to trigger the synergistic anti-tumor therapy. In addition, breast cancer cell line was applied to evaluate the in vitro anti-tumor activity. The multi-modal imaging capacity and tumor-killing efficiency of the designed nanocomposites in vivo was also demonstrated with the 4T1 tumor-bearing mouse model. Results: These nanocomposites could not only perform NIR light triggered photodynamic therapy (PDT) and photothermal therapy (PTT), but also achieve in vivo fluorescence (FL) /multispectral optical tomography (MSOT)/X-ray computed tomography (CT) triple-model bioimaging. What's more, the rod-shape nanoplatform could be endowed with better anti-tumor ability based on the EPR effect and HSA-mediated active tumor targeting. At the same time, the hyperthermia generated by MoS2 could synergistically improve the PDT effect with the acceleration of the blood flow, leading to the increase of the oxygen level in tumor tissue. Conclusion: MSNR@MoS2-HSA/Ce6 proves to be a promising multi-functional nanoplatform for effective treatment of tumor.

Receptor-Mediated and Tumor-Microenvironment Combination-Responsive Ru Nanoaggregates for Enhanced Cancer Phototheranostics

Although phototherapy has been considered as an emerging and promising technology for cancer therapy, its therapeutic specificity and efficacy are severely limited by nonspecific uptake by normal tissues, tumor hypoxia, and so on. Herein, combination-responsive strategy (CRS) is applied to develop one kind of hyaluronic acid-hybridized Ru nanoaggregates (HA-Ru NAs) for enhanced cancer phototherapy via the reasonable integration of receptor-mediated targeting (RMT) and tumor-microenvironment responsiveness (TMR). In this nanosystem, the HA component endows HA-Ru NAs with RMT characteristic to selectively recognize CD44-overexpressing cancer cells, whereas the Ru nanocomponent makes HA-Ru NAs have TMR therapy activity. Specially, the Ru nanocomponent not only has near-infrared-mediated photothermal and photodynamic functions but also can catalyze H₂O₂ in tumor tissue to produce O₂ for the alleviation of tumor hypoxia and toxic •OH for chemodynamic therapy. Benefitting from these, HA-Ru NAs can be considered as a promising kind of CRS nanoplatforms for synergistic photothermal/photodynamic/chemodynamic therapies of cancer, which will not only effectively improve the phototherapeutic specificity and efficacy but also simplify the therapeutic nanosystems. Meanwhile, HA-Ru NAs can serve as a photoacoustic and computed tomography imaging contrast agent to monitor tumors. Such CRS nanoplatforms hold significant potential in improving therapeutic specificity and efficacy for enhanced cancer phototheranostics.

An anti-inflammatory nanoagent for tumor-targeted photothermal therapy

An anti-inflammatory nanoagent based on polydopamine nanospheres was developed to achieve highly efficient photothermal therapy, which can effectively kill cancer cells and simultaneously eliminate photothermal therapy-induced inflammation.

A polydopamine-coated LAPONITE®-stabilized iron oxide nanoplatform for targeted multimodal imaging-guided photothermal cancer therapy

A novel targeted theranostic nanoplatform (LAP–Fe₃O₄@PDA–PEG–PBA) is constructed for magnetic resonance and photoacoustic imaging-guided photothermal therapy of cancer cells overexpressing sialic acid.

Magnetic Drug Delivery: Where the Field Is Going

Targeted delivery of anticancer drugs is considered to be one of the pillars of cancer treatment as it could allow for a better treatment efficiency and less adverse effects. A promising drug delivery approach is magnetic drug targeting which can be realized if a drug delivery vehicle possesses a strong magnetic moment. Here, we discuss different types of magnetic nanomaterials which can be used as magnetic drug delivery vehicles, approaches to magnetic targeted delivery as well as promising strategies for the enhancement of the imaging-guided delivery and the therapeutic action.