Activatable MRI-monitoring gene delivery for the theranostic of renal carcinoma

Progress of Nanomaterials Based on Manganese Dioxide in the Field of Tumor Diagnosis and Therapy

As a pivotal transition metal oxide, manganese dioxide (MnO2) has garnered significant attention owing to its abundant reserves, diverse crystal structures and exceptional performance. Nanosizing MnO2 results in smaller particle sizes, larger specific surface areas, optimized material characteristics, and expanded application possibilities. With the burgeoning research efforts in this field, MnO2 has emerged as a promising nanomaterial for tumor diagnosis and therapy. The distinctive properties of MnO2 in regulating the tumor microenvironment (TME) have attracted considerable interest, leading to a rapid growth in research on MnO2-based nanomaterials for tumor diagnosis and treatment. Additionally, MnO2 nanomaterials are also gradually showing up in the regulation of chronic inflammatory diseases. In this review, we mainly summarized the recent advancements in various MnO2 nanomaterials for tumor diagnosis and therapy. Furthermore, we discuss the current challenges and future directions in the development of MnO2 nanomaterials, while also envisaging their potential for clinical translation.

A lateral flow assay for miRNA-21 based on CRISPR/Cas13a and MnO2 nanosheets-mediated recognition and signal amplification

The point-of-care testing (POCT) of miRNA has significant application in medical diagnosis, yet presents challenges due to their characteristics of high homology, low abundance, and short length, which hinders the achievement of quick detection with high specificity and sensitivity. In this study, a lateral flow assay based on the CRISPR/Cas13a system and MnO2 nanozyme was developed for highly sensitive detection of microRNA-21 (miR-21). The CRISPR/Cas13a cleavage system exhibits the ability to recognize the specific oligonucleotide sequence, where two-base mismatches significantly impact the cleavage activity of the Cas13a. Upon binding of the target to crRNA, the cleavage activity of Cas13a is activated, resulting in the unlocking of the sequence and initiating strand displacement, thereby enabling signal amplification to produce a new sequence P1. When applying the reaction solution to the lateral flow test strip, P1 mediates the capture of MnO2 nanosheets (MnO2 NSs) on the T zone, which catalyzes the oxidation of the pre-immobilized colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) on the T zone and generates the blue-green product (ox-TMB). The change in gray value is directly proportional to the concentration of miR-21, allowing for qualitative detection through visual inspection and quantitative measurement using ImageJ software. This method achieves the detection of miR-21 within a rapid 10-min timeframe, and the limit of detection (LOD) is 0.33 pM. With the advantages of high specificity, simplicity, and sensitivity, the lateral flow test strip and the design strategy hold great potential for the early diagnosis of related diseases.

Manganese Dioxide-Based Nanomaterials for Medical Applications

Manganese dioxide (MnO2) nanomaterials can react with trace hydrogen peroxide (H2O2) to produce paramagnetic manganese (Mn2+) and oxygen (O2), which can be used for magnetic resonance imaging and alleviate the hypoxic environment of tumors, respectively. MnO2 nanomaterials also can oxidize glutathione (GSH) to produce oxidized glutathione (GSSG) to break the balance of intracellular redox reactions. As a consequence of the sensitivity of the tumor microenvironment to MnO2-based nanomaterials, these materials can be used as multifunctional diagnostic and therapeutic platforms for tumor imaging and treatment. Importantly, when MnO2 nanomaterials are implanted along with other therapeutics, synergetic tumor therapy can be achieved. In addition to tumor treatment, MnO2-based nanomaterials display promising prospects for tissue repair, organ protection, and the treatment of other diseases. Herein, we provide a thorough review of recent progress in the use of MnO2-based nanomaterials for biomedical applications, which may be helpful for the design and clinical translation of next-generation MnO2 nanomaterials.

Self-Monitoring Theranostic Nanomaterials: Emerging Visual Agents for Real-Time Monitoring of Tumor Treatment Processes

Self-monitoring in tumor therapy is a concept that allows for real-time monitoring of the location and state of applied nanomaterials. This monitoring relies on dynamic signals, such as wave or magnetic signals, which vary in response to changes in the location and state of nanomaterials. Dynamic changes in nanomaterials can be monitored using dynamic signals, making it possible to determine and control the treatment process. Theranostic nanomaterials, which possess unique physical and chemical properties, have recently been explored as a viable option for self-monitoring. With the help of self-monitoring, theranostic nanomaterials can guide themselves to achieve region-selective treatment with higher controllability and safety. In this review, self-monitoring theranostic nanomaterials will be introduced in three parts according to their roles during therapy: tumor accumulation, tumor therapy, and metabolism. The limitations and future challenges of current self-monitoring theranostic nanomaterials will also be discussed.

Manganese-Based Nanotheranostics for Magnetic Resonance Imaging-Mediated Precise Cancer Management

Manganese (Mn)-based magnetic resonance imaging (MRI) has become a competitive imaging modality for cancer diagnosis due to its advantages of non-invasiveness, high resolution and excellent biocompatibility. In recent years, a variety of Mn contrast agents based on different material systems have been synthesized, and a series of multi-purpose Mn nanocomposites have also emerged, showing satisfactory relaxation efficiency and MRI performance thus possess the transformation and application value in MRI-synergized cancer diagnosis and treatment. This tutorial review starts from the classification and properties of Mn-based nanomaterials, and then summarizes various preparation and functionalization strategies of nanosized Mn contrast agents, especially focuses on the latest progress of Mn contrast agents in MRI-synergized precise cancer theranostics. In addition, present review also discusses the current clinical transformation obstacles such as unclear molecular mechanisms, potential nanotoxicity, and scale production constraints. This paper provides evidence-based recommendations about the future prospects of multifunctional nanoplatforms, as well as technical guidance and panoramic expectations for the design of clinically meaningful cancer management programs.

Target-triggered 'colorimetric-fluorescence' dual-signal sensing system based on the versatility of MnO2 nanosheets for rapid detection of uric acid

A simple dual-signal assay that combined colorimetric and fluorometric strategy for uric acid (UA) rapid detection was designed based on the versatility of facile synthesized MnO2 nanosheet. The oxidization of 3,3',5,5'-tetramethylbenzidine (TMB) and the fluorescence quenching of quantum dots (QDs) occurred simultaneously in the presence of MnO2 nanosheet. UA could decompose MnO2 nanosheet into Mn2+, resulting in the fluorescence recovery of QDs, along with the fading of the blue color of ox TMB. Based on the principles above, the detection of UA could be realized by the change of the dual signals (colorimetric and fluorometric). The linear range of the colorimetric mode was 5-60 μmol L-1, and the limit of detection (LOD) was 2.65 μmol L-1; the linear range of the fluorescence mode was wide at 5-120 μmol L-1, and the LOD could be as low as 1.33 μmol L-1. The method was successfully used for analyzing UA levels in human serum samples, indicating that this new dual-signal method could be applied in clinical diagnosis.

Immunomodulatory activity of manganese dioxide nanoparticles: Promising for novel vaccines and immunotherapeutics

Manganese (Mn), a nutrient inorganic trace element, is necessary for a variety of physiological processes of animal body due to their important roles in oxidative regulation effects and other aspects of activities. Moreover, manganese ion (Mn²⁺) has widely reported to be crucial for the regulations of different immunological responses, thus showing promising application as potential adjuvants and immunotherapeutics. Taking the advantages of Mn-based biological and immunological activities, Manganese dioxide nanoparticles (MnO₂ NPs) are a new type of inorganic nanomaterials with numerous advantages, including simple preparation, low cost, environmental friendliness, low toxicity, biodegradable metabolism and high bioavailability. MnO₂ NPs, as a kind of drug carrier, have also shown the ability to catalyze hydrogen peroxide (H₂O₂) to produce oxygen (O₂) under acidic conditions, which can enhance the efficacy of radiotherapy, chemotherapy and other therapeutics for tumor treatment by remodeling the tumor microenvironment. More importantly, MnO₂ NPs also play important roles in immune regulations both in innate and adaptive immunity. In this review, we summarize the biological activities of Manganese, followed by the introduction for the biological and medical functions and mechanisms of MnO₂ NPs. What's more, we emphatically discussed the immunological regulation effects and mechanisms of MnO₂ NPs, as well as their potentials to serve as adjuvants and immunomodulators, which might benefit the development of novel vaccines and immunotherapies for more effective disease control.

Research trends in biomedical applications of two-dimensional nanomaterials over the last decade - A bibliometric analysis

Two-dimensional (2D) nanomaterials with versatile properties have been widely applied in the field of biomedicine. Despite various studies having reviewed the development of biomedical 2D nanomaterials, there is a lack of a study that objectively summarizes and analyzes the research trend of this important field. Here, we employ a series of bibliometric methods to identify the development of the 2D nanomaterial-related biomedical field during the past 10 years from a holistic point of view. First, the annual publication/citation growth, country/institute/author distribution, referenced sources, and research hotspots are identified. Thereafter, based on the objectively identified research hotspots, the contributions of 2D nanomaterials to the various biomedical subfields, including those of biosensing, imaging/therapy, antibacterial treatment, and tissue engineering are carefully explored, by considering the intrinsic properties of the nanomaterials. Finally, prospects and challenges have been discussed to shed light on the future development and clinical translation of 2D nanomaterials. This review provides a novel perspective to identify and further promote the development of 2D nanomaterials in biomedical research.

DNA aptamer-based dual-responsive nanoplatform for targeted MRI and combination therapy for cancer

Accurate drug delivery is a common topic, and it has always been an aim that scientists strive to achieve. To address this need, multifunctional and stimulus-sensitive nanoplatforms have attracted significant attention. Here we fabricated a glutathione (GSH) and adenosine-5'-triphosphate (ATP) dual-sensitive nanoplatform for controlled drug release and activatable MRI of tumors based on DNA aptamer and manganese dioxide (MnO2) nanosheets. Cleverly utilizing the DNA tunability, AS1411 aptamer which binds nucleolin, a protein specifically expressed on tumor-associated endothelial cells, was designed with ATP aptamer and its cDNA to load the anticancer drug, doxorubicin (Dox). The formed DNA-Dox complex was delivered to the tumor region with the help of MnO2 nanosheets and AS1411 aptamer. Then, the on-demand drug release in tumor cells was realized with the co-effect of the ATP aptamer and GSH reduction. It was found that without the structure of the MnO2 nanosheets being broken by GSH, Dox almost could not be released even in the presence of ATP. Similarly, without ATP, Dox was still maintained in the duplex even with GSH. Further combining the MRI ability and chemodynamic therapy of the produced Mn2+, an improved effect of the inhibition of tumor growth and imaging was achieved. Our designed DNA aptamer-based dual-responsive nanoplatform can realize the targeted drug delivery and MRI of breast tumor cells both in vitro and in vivo.

Recent Advances of Manganese-Based Hybrid Nanomaterials for Cancer Precision Medicine

Cancer precision medicine (CPM) could tailor the best treatment for individual cancer patients, while imaging techniques play important roles in its application. With the characteristics of noninvasion, nonionized, radiation-free, multidimensional imaging function, and real-time monitoring, magnetic resonance imaging (MRI) is an effective way for early tumor detection, and it has become a tower of strength in CPM imaging techniques. Due to linkage with nephrogenic systemic fibrosis (NSF), gadolinium (Gd)-based contrast agent (CA), which was long used in MRI, has been restricted by the Food and Drug Administration (FDA). In this review, we would like to introduce the manganese (Mn)-based CAs that could significantly increase the safety of MRI CAs by realizing more superior performance and functions simultaneously in the diagnosis and treatment of tumors. Also, recent advances in Mn-based hybrid nanomaterials for CPM are summarized and discussed.

Nanostructured manganese dioxide for anticancer applications: preparation, diagnosis, and therapy

Nanostructured manganese dioxide (MnO₂) has attracted extensive attention in the field of anticancer applications. As we all know, the tumor microenvironment is usually characterized by a high glutathione (GSH) concentration, overproduced hydrogen peroxide (H₂O₂), acidity, and hypoxia, which affect the efficacy of many traditional treatments such as chemotherapy, radiotherapy, and surgery. Fortunately, as one kind of redox-active nanomaterial, nanostructured MnO₂ has many excellent properties such as strong oxidation ability, excellent catalytic activity, and good biodegradability. It can be used effectively in diagnosis and treatment when it reacts with some harmful substances in the tumor site. It can not only enhance the therapeutic effect but also adjust the tumor microenvironment. Therefore, it is necessary to present the recent achievements and progression of nanostructured MnO₂ for anticancer applications, including preparation methods, diagnosis, and treatment. Special attention was paid to photodynamic therapy (PDT), bioimaging and cancer diagnosis (BCD), and drug delivery systems (DDS). This review is expected to provide helpful guidance on further research of nanostructured MnO₂ for anticancer applications.