68Ga-Labeled Magnetic-NIR Persistent Luminescent Hybrid Mesoporous Nanoparticles for Multimodal Imaging-Guided Chemotherapy and Photodynamic Therapy

Current Developments in Emerging Lanthanide-Doped Persistent Luminescent Scintillators and Their Applications

Lanthanide-doped scintillators have the ability to convert the absorbed X-ray irradiation into ultraviolet (UV), visible (Vis), or near-infrared (NIR) light. Lanthanide-doped scintillators with excellent persistent luminescence (PersL) are emerging as a new class of PersL materials recently. They have attracted great attention due to their unique "self-luminescence" characteristic and potential applications. In this review, we comb through and focus on current developments of lanthanide-doped persistent luminescent scintillators (PersLSs), including their PersL mechanism, synthetic methods, tuning of PersL properties (e. g. emission wavelength, intensity, and duration time), as well as their promising applications (e. g. information storage, encryption, anti-counterfeiting, bio-imaging, and photodynamic therapy). We hope this review will provide valuable guidance for the future development of PersLSs.

Persistent luminescent nanophosphors for applications in cancer theranostics, biomedical, imaging and security

The extraordinary and unique properties of persistent luminescent (PerLum) nanostructures like storage of charge carriers, extended afterglow, and some other fascinating characteristics like no need for in-situ excitation, and rechargeable luminescence make such materials a primary candidate in the fields of bio-imaging and therapeutics. Apart from this, due to their extraordinary properties they have also found their place in the fields of anti-counterfeiting, latent fingerprinting (LPF), luminescent markings, photocatalysis, solid-state lighting devices, glow-in-dark toys, etc. Over the past few years, persistent luminescent nanoparticles (PLNPs) have been extensively used for targeted drug delivery, bio-imaging guided photodynamic and photo-thermal therapy, biosensing for cancer detection and subsequent treatment, latent fingerprinting, and anti-counterfeiting owing to their enhanced charge storage ability, in-vitro excitation, increased duration of time between excitation and emission, low tissue absorption, high signal-to-noise ratio, etc. In this review, we have focused on most of the key aspects related to PLNPs, including the different mechanisms leading to such phenomena, key fabrication techniques, properties of hosts and different activators, emission, and excitation characteristics, and important properties of trap states. This review article focuses on recent advances in cancer theranostics with the help of PLNPs. Recent advances in using PLNPs for anti-counterfeiting and latent fingerprinting are also discussed in this review.

Multifunctional mesoporous silica nanoparticles for biomedical applications

Mesoporous silica nanoparticles (MSNs) are recognized as a prime example of nanotechnology applied in the biomedical field, due to their easily tunable structure and composition, diverse surface functionalization properties, and excellent biocompatibility. Over the past two decades, researchers have developed a wide variety of MSNs-based nanoplatforms through careful design and controlled preparation techniques, demonstrating their adaptability to various biomedical application scenarios. With the continuous breakthroughs of MSNs in the fields of biosensing, disease diagnosis and treatment, tissue engineering, etc., MSNs are gradually moving from basic research to clinical trials. In this review, we provide a detailed summary of MSNs in the biomedical field, beginning with a comprehensive overview of their development history. We then discuss the types of MSNs-based nanostructured architectures, as well as the classification of MSNs-based nanocomposites according to the elements existed in various inorganic functional components. Subsequently, we summarize the primary purposes of surface-functionalized modifications of MSNs. In the following, we discuss the biomedical applications of MSNs, and highlight the MSNs-based targeted therapeutic modalities currently developed. Given the importance of clinical translation, we also summarize the progress of MSNs in clinical trials. Finally, we take a perspective on the future direction and remaining challenges of MSNs in the biomedical field.

Recent advances in magnetic nanocarriers for tumor treatment

Magnetic nanocarriers are nano-platforms that integrate multiple moieties based on magnetic nanoparticles for diagnostic and therapeutic purposes. In recent years, they have become an advanced platform for tumor treatment due to their wide application in magnetic resonance imaging (MRI), biocatalysis, magneto-thermal therapy (MHT), and photoresponsive therapy. Drugs loaded into magnetic nanocarriers can efficiently be directed to targeted areas by precisely reshaping their structural properties. Magnetic nanocarriers allow us to track the location of the therapeutic agent, continuously control the therapeutic process and eventually assess the efficacy of the treatment. They are typically used in synergistic therapeutic applications to achieve precise and effective tumor treatment. Here we review their latest applications in tumor treatment, including stimuli-responsive drug delivery, MHT, photoresponsive therapy, immunotherapy, gene therapy, and synergistic therapy. We consider reducing toxicity, improving antitumor efficacy, and the targeting accuracy of magnetic nanocarriers. The challenges of their clinical translation and prospects in cancer therapy are also discussed.

Persistent luminescent metal-organic framework nanocomposite enables autofluorescence-free dual modal imaging-guided drug delivery

Molecular imaging-guided therapy was essential for realizing precise cancer intervention, while designing an imaging platform to achieve autofluorescence-free imaging for dual modal imaging-guided drug delivery remains a challenge. Near-infrared persistent luminescence nanoparticles (NIR PLNPs) were promising for tumor imaging due to no background interference from the tissue. Herein, a persistent luminescent metal-organic framework (PLNPs@MIL-100(Fe)) is prepared via a layer-by-layer method for dual-modal imaging-guided drug delivery. The PLNPs@MIL-100(Fe) exhibit NIR persistent luminescence emitting and T₂-weighted signal, achieving precise in vivo dual-modal imaging of tumor-bearing mice by providing high spatial resolution MR imaging and autofluorescence-free NIR imaging. The porous MIL-100(Fe) shell provides PLNPs@MIL-100(Fe) with up to 87.1% drug loading capacity and acid-triggered drug release for drug delivery. We envision that the proposed PLNPs@MIL-100(Fe) platform would provide an effective approach for precise tumor imaging and versatile drug delivery.

Perspective and Prospects on persistent luminescent nanoparticles for biological imaging and tumor therapy

Persistent luminescent nanoparticles (PLNPs) are photoluminescent materials that can still emit luminescence after the cessation of the excitation light source. In recent years, due to their unique optical properties, the PLNPs have attracted extensive attention in the biomedical field. Since the PLNPs effectively eliminate autofluorescence interference from biological tissues, many researchers have contributed a lot of work in the fields of biological imaging and tumor therapy. This article mainly introduces the synthesis methods of the PLNPs and their progress in the application of biological imaging and tumor therapy, as well as the challenges and development prospects.

NIR-II-triggered photothermal therapy with Au@PDA/PEG-PI for targeted downregulation of PSMA in prostate cancer

Although positron emission tomography (PET) imaging products targeting prostate-specific membrane antigen (PSMA) have been approved for marketing, clinical challenges remain in the study of its use as a therapeutic target, such as the complex synthesis process and side effects after treatment. Here, we developed a strategy for targeted photothermal therapy (PTT) using PSMA as the target. The results of molecular docking demonstrated that the synthesized PEG modified urea-based PSMA inhibitor (small molecular PSMA inhibitor, PI) PI-PEG has a high affinity energy (binding energy = - 8.3 kcal mol^-1) for the PSMA target. Therefore, modification of PI-PEG onto the surface of gold@polydopamine (Au@PDA) with NIR-II absorption could enable targeted PTT against PSMA. This work revealed that the prepared Au@PDA/PEG-PI were not only highly selective for PSMA, but also could efficiently ablate PSMA expression by targeted PTT at the maximum permissible exposure (MPE) of the NIR-II laser. Moreover, Au@PDA/PEG-PI also have potential for photoacoustic (PA) imaging and computed tomography (CT) imaging. As the first strategy to downregulate the expression of PSMA and successfully inhibit prostate cancer by targeted PTT, this study case provides a new idea for the clinical translation of PSMA as an integrated target for tumor diagnosis and anti-tumor treatment. STATEMENT OF SIGNIFICANCE: (1) Au@PDA/PEG-PI NPs were the novel PTT agent to target PSMA and successfully down-regulate PSMA expression. (2) Molecular docking results demonstrated that PI-PEG inhibitors have a high affinity energy for PSMA (binding energy = - 8.3 kcal mol^-1). (3) Au@PDA/PEG-PI NPs can be targeted for efficient PTT at the MPE of the NIR-II laser. (4) Au@PDA/PEG-PI NPs also have the potential for PA and CT imaging.

Tumor microenvironment-responsive histidine modified-hyaluronic acid-based MnO2 as in vivo MRI contrast agent

Tumor microenvironment (TME)-responsive manganese dioxide (MnO₂) nanoparticles as a good T₁ contrast agent could reduce unwanted toxicity and improve the accuracy of cancer detection. Despite these distinct advantages of MnO₂-based nanoparticles, their synthesis involves multi-step processes with relatively long synthesis times. In this study, we synthesized histidine-modified hyaluronic acid (HA-His), and the prepared HA-His conjugates quickly reduce permanganate to MnO₂, leading to facile production of HA-His/MnO₂ nanoparticles with good water-dispersibility and stability under biological conditions. The synthesized HA-His/MnO₂ nanoparticles readily responded to the TME (low pH, high H₂O₂, and high glutathione), and they were internalized into SCC7 cells with high CD44 expression. Moreover, the systemically administered HA-His/MnO₂ nanoparticles with biocompatibility were specifically accumulated in tumor tissues, thereby efficiently enhancing T₁ contrast in MRI. Therefore, the HA-His/MnO₂ nanoparticles synthesized herein can be used as a promising T₁ contrast agent for tumor MR imaging.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

Key Parameters for the Rational Design, Synthesis, and Functionalization of Biocompatible Mesoporous Silica Nanoparticles

Over the last few years, research on silica nanoparticles has rapidly increased. Particularly on mesoporous silica nanoparticles (MSNs), as nanocarriers for the treatment of various diseases because of their physicochemical properties and biocompatibility. The use of MSNs combined with therapeutic agents can provide better encapsulation and effective delivery. MSNs as nanocarriers might also be a promising tool to lower the therapeutic dosage levels and thereby to reduce undesired side effects. Researchers have explored several routes to conjugate both imaging and therapeutic agents onto MSNs, thus expanding their potential as theranostic platforms, in order to allow for the early diagnosis and treatment of diseases. This review introduces a general overview of recent advances in the field of silica nanoparticles. In particular, the review tackles the fundamental aspects of silicate materials, including a historical presentation to new silicates and then focusing on the key parameters that govern the tailored synthesis of functional MSNs. Finally, the biomedical applications of MSNs are briefly revised, along with their biocompatibility, biodistribution and degradation. This review aims to provide the reader with the tools for a rational design of biocompatible MSNs for their application in the biomedical field. Particular attention is paid to the role that the synthesis conditions have on the physicochemical properties of the resulting MSNs, which, in turn, will determine their pharmacological behavior. Several recent examples are highlighted to stress the potential that MSNs hold as drug delivery systems, for biomedical imaging, as vaccine adjuvants and as theragnostic agents.

High Drug-Loading Nanomedicines for Tumor Chemo-Photo Combination Therapy: Advances and Perspectives

The combination of phototherapy and chemotherapy (chemo−photo combination therapy) is an excellent attempt for tumor treatment. The key requirement of this technology is the high drug-loading nanomedicines, which can load either chemotherapy drugs or phototherapy agents at the same nanomedicines and simultaneously deliver them to tumors, and play a multimode therapeutic role for tumor treatment. These nanomedicines have high drug-loading efficiency (>30%) and good tumor combination therapeutic effect with important clinical application potential. Although there are many reports of high drug-loading nanomedicines for tumor therapy at present, systematic analyses on those nanomedicines remain lacking and a comprehensive review is urgently needed. In this review, we systematically analyze the current status of developed high drug-loading nanomedicines for tumor chemo−photo combination therapy and summarize their types, methods, drug-loading properties, in vitro and in vivo applications. The shortcomings of the existing high drug-loading nanomedicines for tumor chemo−photo combination therapy and the possible prospective development direction are also discussed. We hope to attract more attention for researchers in different academic fields, provide new insights into the research of tumor therapy and drug delivery system and develop these nanomedicines as the useful tool for tumor chemo−photo combination therapy in the future.

HKUST-1 nano metal-organic frameworks combined with ZnGa2O4:Cr3+ near-infrared persistent luminescence nanoparticles for in vivo imaging and tumor chemodynamic and photothermal synergic therapy

The multifunctional theranostic nanoplatform based on the combination of persistent luminescent nanoparticles (PLNPs) and metal-organic frameworks (MOFs) has both in vivo imaging and tumor therapeutic drug-loading functions, providing a new strategy for accurate and effective tumor diagnosis and treatment. Herein, the near-infrared (NIR) PLNP SiO₂@Zn_1.05Ga_1.9O₄:Cr was combined with HKUST-1 MOFs to form a core-shell structure theranostic nanoplatform which possessed the triple function of autofluorescence-free NIR PersL bioimaging, tumor chemodynamic therapy (CDT), and tumor photothermal therapy (PTT). Also, the photothermal conversion efficiency reached 58.7%, which is superior to the reported nano metal-organic framework (NMOF) photothermal reagents. We demonstrated that the nanoplatform could enter the tumors of mice within 0.5 h and could be target-activated by H₂O₂ and H₂S in the tumor cells, resulting in effective PTT and CDT synergistic treatment. Tumor-bearing mice experiments showed that the tumor could be completely cured without harming normal tissue. This theranostic nanoplatform may provide a promising strategy showing imaging, PTT, and CDT synergistic treatment tri-mode for clinical cancer therapy.

Multifunction in One Nanoparticle for Anticancer Therapy: Bowl-Shaped Au@PDA Yolk-Shell NPs

Multifunctional nanoparticles (NPs) with simultaneous multimodal therapeutic and imaging capabilities are very necessary for biomedical applications. We successfully prepared bowl-shaped gold@polydopamine yolk-shell NPs (bowl-shaped Au@PDA YNPs) by a novel and facile method. The unique bowl-like structure enables a drug loading rate of 92% (920 μg mg^-1). The bowl-shaped Au@PDA YNPs are biocompatible, have good photothermal conversion and strong near-infrared (NIR) absorption, and can control drug release under pH/NIR dual response. Bowl-shaped Au@PDA YNPs can also be employed as contrast agents for computed tomography/photoacoustic imaging for dual-modal imaging-guided chemotherapy and photothermal therapy due to the presence of Au NPs.

Persistent Luminescence-Based Theranostics for Real-Time Monitoring and Simultaneously Launching Photodynamic Therapy of Bacterial Infections

External light irradiation is usually required in bacterial infection theranostics; however, it is always accompanied by limited light penetration, imaging interference, and incomplete bacterial destruction. Herein, a feasible "image-launching therapy" strategy is developed to integrate real-time optical imaging and simultaneous photodynamic therapy (PDT) of bacterial infections into persistent luminescence (PL) nanoparticles (NPs). Mesoporous silica NPs are used as a substrate for in situ deposition of PL nanodots of ZnGa₂ O₄ :Cr³⁺ to obtain mPL NPs, followed by surface grafting with silicon phthalocyanine (Si-Pc) and electrostatic assembly of cyanine 7 (Cy7) to fabricate mPL@Pc-Cy NPs. The PL emission of light-activated mPL@Pc-Cy NPs is quenched by Cy7 assembly at physiological conditions through the fluorescence resonance energy transfer effect, but is rapidly restored after disassembly of Cy7 in response to bacterial infections. The self-illuminating capabilities of NPs avoid tissue autofluorescence under external light irradiation and achieve real-time colorimetric imaging of bacterial infections. In addition, the afterglow of mPL NPs can persistently excite Si-Pc photosensitizers to promote PDT efficacy for bacterial elimination and accelerate wound full recovery with normal histologic features. Thus, this study expands the theranostic strategy for precise imaging and simultaneous non-antibiotic treatment of bacterial infections without causing side effects to normal tissues.

Synergic Antitumor Effect of Photodynamic Therapy and Chemotherapy Mediated by Nano Drug Delivery Systems

This review provides a summary of recent progress in the development of different nano-platforms for the efficient synergistic effect between photodynamic therapy and chemotherapy. In particular, this review focuses on various methods in which photosensitizers and chemotherapeutic agents are co-delivered to the targeted tumor site. In many cases, the photosensitizers act as drug carriers, but this review, also covers different types of appropriate nanocarriers that aid in the delivery of photosensitizers to the tumor site. These nanocarriers include transition metal, silica and graphene-based materials, liposomes, dendrimers, polymers, metal–organic frameworks, nano emulsions, and biologically derived nanocarriers. Many studies have demonstrated various benefits from using these nanocarriers including enhanced water solubility, stability, longer circulation times, and higher accumulation of therapeutic agents/photosensitizers at tumor sites. This review also describes novel approaches from different research groups that utilize various targeting strategies to increase treatment efficacy through simultaneous photodynamic therapy and chemotherapy.

Combinatorial Therapeutic Approaches with Nanomaterial-Based Photodynamic Cancer Therapy

Photodynamic therapy (PDT), in which a light source is used in combination with a photosensitizer to induce local cell death, has shown great promise in therapeutically targeting primary tumors with negligible toxicity and minimal invasiveness. However, numerous studies have shown that noninvasive PDT alone is not sufficient to completely ablate tumors in deep tissues, due to its inherent shortcomings. Therefore, depending on the characteristics and type of tumor, PDT can be combined with surgery, radiotherapy, immunomodulators, chemotherapy, and/or targeted therapy, preferably in a patient-tailored manner. Nanoparticles are attractive delivery vehicles that can overcome the shortcomings of traditional photosensitizers, as well as enable the codelivery of multiple therapeutic drugs in a spatiotemporally controlled manner. Nanotechnology-based combination strategies have provided inspiration to improve the anticancer effects of PDT. Here, we briefly introduce the mechanism of PDT and summarize the photosensitizers that have been tested preclinically for various cancer types and clinically approved for cancer treatment. Moreover, we discuss the current challenges facing the combination of PDT and multiple cancer treatment options, and we highlight the opportunities of nanoparticle-based PDT in cancer therapies.

Bacterial microenvironment-responsive dual-channel smart imaging guided on-demand self-regulated photodynamic/chemodynamic synergistic sterilization and wound healing

Bacterial infections pose a serious threat to public health. The integration of photodynamic therapy (PDT) and chemodynamic therapy (CDT) has emerged as a promising means to combat bacterial infection. However,...

Polydopamine-coated UiO-66 nanoparticles loaded with perfluorotributylamine/tirapazamine for hypoxia-activated osteosarcoma therapy

Background

Hypoxia is a characteristic of solid tumors that can lead to tumor angiogenesis and early metastasis, and addressing hypoxia presents tremendous challenges. In this work, a nanomedicine based on oxygen-absorbing perfluorotributylamine (PFA) and the bioreductive prodrug tirapazamine (TPZ) was prepared by using a polydopamine (PDA)-coated UiO-66 metal organic framework (MOF) as the drug carrier.

Results

The results showed that TPZ/PFA@UiO-66@PDA nanoparticles significantly enhanced hypoxia, induced cell apoptosis in vitro through the oxygen-dependent HIF-1α pathway and decreased oxygen levels in vivo after intratumoral injection. In addition, our study demonstrated that TPZ/PFA@UiO-66@PDA nanoparticles can accumulate in the tumor region after tail vein injection and effectively inhibit tumor growth when combined with photothermal therapy (PTT). TPZ/PFA@UiO-66@PDA nanoparticles increased HIF-1α expression while did not promote the expression of CD31 in vivo during the experiment.

Conclusions

By using TPZ and PFA and the enhanced permeability and retention effect of nanoparticles, TPZ/PFA@UiO-66@PDA can target tumor tissues, enhance hypoxia in the tumor microenvironment, and activate TPZ. Combined with PTT, the growth of osteosarcoma xenografts can be effectively inhibited.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01013-0.

Biodegradable manganese engineered nanocapsules for tumor-sensitive near-infrared persistent luminescence/magnetic resonance imaging and simultaneous chemotherapy

Rationale: Near-Infrared persistent luminescence (NIR-PL) nanomaterials that can continually emit low-energy photons after ceasing excitation has emerged as a new generation of theranostic nanoparticle drug delivery systems (NDDSs) for imaging-guided cancer therapy, which stems from their special ability to completely avoid tissue autofluorescence interference. However, unresponsive diagnostic capability, inefficient drug delivery, and poor biodegradability limit the efficacy of most reported NIR-PL-based NDDSs. Methods: Herein, a multifaceted tumor microenvironment (TME)-degradable theranostic drug delivery nanocapsule based on an ultrasmall persistent phosphor with a hollow mesoporous manganese-doped, DOX-loaded silica shell (Mn-ZGOCS-PEG) is developed to overcome the above drawbacks. Results: We demonstrate that the well-designed nanocapsule enables tumor-responsive controlled drug release with ameliorated therapeutic efficacy, TME-responsive autofluorescence interference-free NIR-PL tracing, and manganese-enhanced magnetic resonance (Mn-MR) monitoring for practical dual-modality image-guided antitumor treatment in vivo. Conclusion: Our results indicate that Mn-ZGOCS-PEG nanocapsules enable tumor-targeting augmented chemotherapy under the guidance of TME-responsive dual-MR/NIR-PL-modality imaging in vivo. We believe that our work provides a new paradigm for the development of smart NIR-PL-based NDDSs with ultrasensitive multimodal diagnostic capability, enhanced anticancer effect, and efficient biodegradability.

An Update on Mesoporous Silica Nanoparticle Applications in Nanomedicine

The efficient and safe delivery of therapeutic drugs, proteins, and nucleic acids are essential for meaningful therapeutic benefits. The field of nanomedicine shows promising implications in the development of therapeutics by delivering diagnostic and therapeutic compounds. Nanomedicine development has led to significant advances in the design and engineering of nanocarrier systems with supra-molecular structures. Smart mesoporous silica nanoparticles (MSNs), with excellent biocompatibility, tunable physicochemical properties, and site-specific functionalization, offer efficient and high loading capacity as well as robust and targeted delivery of a variety of payloads in a controlled fashion. Such unique nanocarriers should have great potential for challenging biomedical applications, such as tissue engineering, bioimaging techniques, stem cell research, and cancer therapies. However, in vivo applications of these nanocarriers should be further validated before clinical translation. To this end, this review begins with a brief introduction of MSNs properties, targeted drug delivery, and controlled release with a particular emphasis on their most recent diagnostic and therapeutic applications.

Recent Progress of Near-Infrared Persistent Phosphors in Bio-related and Emerging Applications

Near-infrared persistent phosphors (NIR-PPs) are an emerging category of luminescent materials that can continuously emit NIR luminescence with super-long decay time of minutes, hours, or even days after the excitation ceases. Their unique excitation-free long-lasting afterglow, together with the NIR emission, has not only attracted wide research interests in the areas of photochemistry, photophysics, spectroscopy, and materials science, but also stimulated advanced applications in biosensing, bioimaging, biomedicine, and therapy in the past decade. Beyond these bio-related applications, the active research field triggers a number of novel applications recently. In this review, a brief outline of NIR-PPs including the luminescence mechanism, main material systems, and how they were applied into various fields was depicted. Particular emphasis was put on the emerging applications outside the field of biology. Future perspectives in this exploration research area were also presented. We hope this review can help researchers grab the latest information in the fast-growing field of NIR-PPs.