Reactive Oxygen Correlated Chemiluminescent Imaging of a Semiconducting Polymer Nanoplatform for Monitoring Chemodynamic Therapy

DNA-mediated self-assembly oxidative damage amplifier combined with copper and MTH1 inhibitor for cancer therapy

Chemo-dynamic therapy (CDT) has a great potential in tumor extirpation. It entails producing hypertoxic reactive oxygen species (ROS) that damage the DNA of tumor cells and other biomacromolecules. However, the efficiency of CDT is severely hampered by the massive presence of glutathione (GSH) in tumor cells and the interference of ROS defense systems, such as Mutt homolog 1 (MTH1) protein sanitizes ROS-oxidized nucleotide pools. In this research, DNA-mediated self-assembly nanoparticles (HTCG@TA NPs) were engineered with high-performance amplified oxidative damage and gene therapy effect for synergistic anti-tumor treatment. Cu2+ was converted into Cu + by redox reactions to deplete GSH while H2O2 was catalyzed to generate hydroxyl radicals (·OH). As a result, the ROS level was evidently improved. Moreover, controllable-released TH588 prevented MTH1-mediated DNA repairing, thus aggravated oxidative damage to tumor cells. Meanwhile, the released functional nucleic acid G3139 downregulated the expression of Bcl-2, and accelerated the apoptosis of tumor cells. In conclusion, the HTCG@TA demonstrated significant effect in oxidative damage amplification and tumor inhibition both in vitro and in vivo, which has provided a new outlook for the clinical application of chemo-dynamic tumor treatment and synergistic gene therapy with self-delivery nanoplatforms.

Tailored biomimetic nanoreactor improves glioma chemodynamic treatment via triple glutathione depletion and prompt acidity elevation

Chemodynamic therapy (CDT) is an emerging antitumor strategy utilizing iron-initiated Fenton reaction to destroy tumor cells by converting endogenous H2O2 into highly toxic hydroxyl radical (OH). However, the intratumoral overexpressed glutathione (GSH) and deficient acid greatly reduce CDT efficacy because of OH scavenging and decreased OH production efficiency. Even worse, the various physiological barriers, especially in glioma, further put the brakes on the targeted delivery of Fenton agents. Herein, by exploring the thiol reaction potential of 5,5'-dithiobis-2-nitrobenzoic acid (DTNB), we have constructed a tailored biomimetic nanoreactor to improve glioma CDT efficacy through synchronous GSH exhaustion and acidity elevation. The biomimetic nanoreactor was fabricated by employing DTNB to drive the nano-assembly of BSA molecules, followed by loading the carrier onto the cell surface of neutrophils via disulfide-thiol exchange. Upon sensing the inflammatory signal, the nanoreactor hijacked by neutrophils efficiently targets to the tumor site, which then dually depletes GSH by disulfide bond stabilizing the nanostructure and the following liberated Fe (III). In particular, the simultaneously released DTNB can not only consume the residual GSH, but also produce 5-thio-2-nitrobenzoic acid (TNB) promptly, resulting in accelerated Fenton reaction. Through in vitro and in vivo experiments, we demonstrate the exhaustive and synchronous regulation of Fenton chemistry could potentially serve as a novel CDT strategy for glioma.

Biomaterials enhancing localized cancer therapy activated anti-tumor immunity: a review

Localized cancer therapies such as radiotherapy, phototherapy, and chemotherapy are precise cancer treatment strategies aimed at minimizing systemic side effects. However, cancer metastasis remains the primary cause of mortality among cancer patients in clinical settings, and localized cancer treatments have limited efficacy against metastatic cancer. Therefore, researchers are exploring strategies that combine localized therapy with immunotherapy to activate robust anti-tumor immune responses, thereby eradicating metastatic cancer. Biomaterials, as novel materials, exhibit great potential in biomedical applications and have achieved great progress in clinic translation. This review introduces biomaterials and their applications in research focused on enhancing localized cancer treatment activated anti-tumor immunity. Additionally, the current challenges and future directions of biomaterials are also discussed, providing insights and references for related research.

Studies related to the enhanced the effect of 5-aminolevulinic acid-based photodynamic therapy combined with tirapazamine

OBJECTIVE

5-aminolevulinic acid (5-ALA) is a precursor of the photosensitizer Protoporphyrin IX (PpIX) and photodynamic therapy (PDT) with 5-ALA has been used in clinical practice. However, tumor cellular hypoxia severely affects the efficiency of photodynamic therapy. In this study, photodynamic therapy was combined with tirapazamine to investigate the effects of the combined intervention and the related mechanisms it may involve.

METHODS

Colony formation assays were used to demonstrate cell proliferation. Transwell assays were performed to observe the effect on cell invasion and metastasis after the corresponding intervention. DCFH-DA probe was used to detect the reactive oxygen species content. Flow cytometry was used to detect the effects of the interventions on apoptosis and cell cycle. The relevant pathways that may be involved are explored by examining the expression levels of the relevant proteins and genes.

RESULTS

Colony formation assays indicated that the combined intervention inhibited cell proliferation. Transwell assays demonstrated that PDT combined with TPZ effectively inhibited tumor cell invasion and metastasis. In addition, fluorescence intensity generated by DCFH-DA oxidation was detected indicating that the combined intervention increased the formation of reactive oxygen species. Flow cytometry clearly showed that the combination of PDT and TPZ further increased apoptosis and cell cycle arrest. The results of western blotting and qRT-PCR experiments confirmed that the combination therapy inhibited HIF-1α/VEGF axis and the PI3K/Akt/mTOR pathway activation.

CONCLUSION

5-ALA-PDT combined with TPZ can inhibit cell proliferation, increase apoptosis, and inhibit the PI3K/Akt/mTOR pathway, thus inhibiting tumor growth and metastasis and improving anti-cancer effects.

A universal nanoreactor triggering butterfly effect for encouraging Fenton/Fenton-like reactions and chemodynamic therapy

Fenton/Fenton-like reaction induced chemical dynamic therapy (CDT) has been widely recognized in tumor therapy. Due to the low efficiency of conversion from high-valent metal ions (M(n+1)+) to low-valent ions (Mn+) in the Fenton/Fenton-like catalytic process, enhancing the conversion efficiency safely and effectively would create a great opportunity for the clinical application of CDT. In the study, a universal nanoreactor (NR) consisting of liposome (Lip), tumor cell membrane (CM), and bis(2,4,5-trichloro-6-carboxyphenyl) oxalate (CPPO) is developed to tackle this challenge. The CPPO was first discovered to decompose under weak acidity and H2O2 conditions to generate carboxylic acids (R'COOH) and alcohols (R'OH) with reducibility, which will reduce M(n+1)+ to Mn+ and magnify the effect of CDT. Furthermore, glucose oxidase (GOx) was introduced to decompose glucose in tumor and generate H2O2 and glucose acid, which promote the degradation of CPPO, further strengthening the efficiency of CDT, leading to a butterfly effect. This demonstrated that the butterfly effect triggered by NR and GOx encourages Fenton/Fenton-like reactions of Fe3O4 and MoS2, thereby enhancing the tumor inhibition effect. The strategy of combining GOx and CPPO to strengthen the Fenton/Fenton-like reaction is a universal strategy, which provides a new and interesting perspective for CPPO in the application of CDT, reflecting the exquisite integration of Fenton chemistry and catalytic medicine.

Reactive Oxygen-Correlated Photothermal Imaging of Smart COF Nanoreactors for Monitoring Chemodynamic Sterilization and Promoting Wound Healing

Chemodynamic therapy (CDT) has emerged as a promising approach for treating infected diabetic wounds, while reliable imaging technology for simultaneous monitoring of ROS and therapeutic processes is still a formidable challenge. Herein, smart covalent organic framework (COF) nanoreactors (COF NRs) are constructed by hyaluronic acid (HA) packaged glucose oxidase (GOx) covalently linked Fe-COF for diabetic wound healing. Upon the breakdown of the HA protective layer, GOx consumes glucose to produce gluconic acid and hydrogen peroxide (H2O2), resulting in decreased local pH and H2O2 supplementation. Density functional theory (DFT) calculations show that Fe-COF has high catalytic activity towards H2O2, leading to in situ generation of hydroxyl radicals (·OH) for sterilization, and the localized downregulation of glucose effectively improved the microenvironment of diabetic wounds. Meanwhile, based on the near-infrared photothermal imaging of oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB), the authors showed that TMB can be applied for the point-of-care testing of ·OH and glucose, and assessing the sterilization progress in vivo. More significantly, the facile photothermal signaling strategy can be extended to monitor various ROS-mediated therapeutic systems, enabling accurate prediction of treatment outcomes.

Immunological nanomaterials to combat cancer metastasis

Metastasis causes greater than 90% of cancer-associated deaths, presenting huge challenges for detection and efficient treatment of cancer due to its high heterogeneity and widespread dissemination to various organs. Therefore, it is imperative to combat cancer metastasis, which is the key to achieving complete cancer eradication. Immunotherapy as a systemic approach has shown promising potential to combat metastasis. However, current clinical immunotherapies are not effective for all patients or all types of cancer metastases owing to insufficient immune responses. In recent years, immunological nanomaterials with intrinsic immunogenicity or immunomodulatory agents with efficient loading have been shown to enhance immune responses to eliminate metastasis. In this review, we would like to summarize various types of immunological nanomaterials against metastasis. Moreover, this review will summarize a series of immunological nanomaterial-mediated immunotherapy strategies to combat metastasis, including immunogenic cell death, regulation of chemokines and cytokines, improving the immunosuppressive tumour microenvironment, activation of the STING pathway, enhancing cytotoxic natural killer cell activity, enhancing antigen presentation of dendritic cells, and enhancing chimeric antigen receptor T cell therapy. Furthermore, the synergistic anti-metastasis strategies based on the combinational use of immunotherapy and other therapeutic modalities will also be introduced. In addition, the nanomaterial-mediated imaging techniques (e.g., optical imaging, magnetic resonance imaging, computed tomography, photoacoustic imaging, surface-enhanced Raman scattering, radionuclide imaging, etc.) for detecting metastasis and monitoring anti-metastasis efficacy are also summarized. Finally, the current challenges and future prospects of immunological nanomaterial-based anti-metastasis are also elucidated with the intention to accelerate its clinical translation.

Recent Progress in Anti-Tumor Nanodrugs Based on Tumor Microenvironment Redox Regulation

The growth state of tumor cells is strictly affected by the specific abnormal redox status of the tumor microenvironment (TME). Moreover, redox reactions at the biological level are also central and fundamental to essential energy metabolism reactions in tumors. Accordingly, anti-tumor nanodrugs targeting the disruption of this abnormal redox homeostasis have become one of the hot spots in the field of nanodrugs research due to the effectiveness of TME modulation and anti-tumor efficiency mediated by redox interference. This review discusses the latest research results of nanodrugs in anti-tumor therapy, which regulate the levels of oxidants or reductants in TME through a variety of therapeutic strategies, ultimately breaking the original "stable" redox state of the TME and promoting tumor cell death. With the gradual deepening of study on the redox state of TME and the vigorous development of nanomaterials, it is expected that more anti-tumor nano drugs based on tumor redox microenvironment regulation will be designed and even applied clinically.

Recent Advances of Aminopeptidases-Responsive Small-Molecular Probes for Bioimaging

Aminopeptidases, enzymes with critical roles in human body, are emerging as vital biomarkers for metabolic processes and diseases. Aberrant aminopeptidase levels are often associated with diseases, particularly cancer. Small-molecule probes, such as fluorescent, fluorescent/photoacoustics, bioluminescent, and chemiluminescent probes, are essential tools in the study of aminopeptidases-related diseases. The fluorescent probes provide real-time insights into protein activities, offering high sensitivity in specific locations, and precise spatiotemporal results. Additionally, photoacoustic probes offer signals that are able to penetrate deeper tissues. Bioluminescent and chemiluminescent probes can enhance in vivo imaging abilities by reducing the background. This comprehensive review is focused on small-molecule probes that respond to four key aminopeptidases: aminopeptidase N, leucine aminopeptidase, Pyroglutamate aminopeptidase 1, and Prolyl Aminopeptidase, and their utilization in imaging tumors and afflicted regions. In this review, the design strategy of small-molecule probes, the variety of designs from previous studies, and the opportunities of future bioimaging applications are discussed, serving as a roadmap for future research, sparking innovations in aminopeptidase-responsive probe development, and enhancing our understanding of these enzymes in disease diagnostics and treatment.

Chemiluminescent Conjugated Polymer Nanoparticles for Deep-Tissue Inflammation Imaging and Photodynamic Therapy of Cancer

Deep-tissue optical imaging and photodynamic therapy (PDT) remain a big challenge for the diagnosis and treatment of cancer. Chemiluminescence (CL) has emerged as a promising tool for biological imaging and in vivo therapy. The development of covalent-binding chemiluminescence agents with high stability and high chemiluminescence resonance energy transfer (CRET) efficiency is urgent. Herein, we design and synthesize an unprecedented chemiluminescent conjugated polymer PFV-Luminol, which consists of conjugated polyfluorene vinylene (PFV) main chains and isoluminol-modified side chains. Notably, isoluminol groups with chemiluminescent ability are covalently linked to main chains by amide bonds, which dramatically narrow their distance, greatly improving the CRET efficiency. In the presence of pathologically high levels of various reactive oxygen species (ROS), especially singlet oxygen (1O2), PFV-Luminol emits strong fluorescence and produces more ROS. Furthermore, we construct the PFV-L@PEG-NPs and PFV-L@PEG-FA-NPs nanoparticles by self-assembly of PFV-Luminol and amphiphilic copolymer DSPE-PEG/DSPE-PEG-FA. The chemiluminescent PFV-L@PEG-NPs nanoparticles exhibit excellent capabilities for in vivo imaging in different inflammatory animal models with great tissue penetration and resolution. In addition, PFV-L@PEG-FA-NPs nanoparticles show both sensitive in vivo chemiluminescence imaging and efficient chemiluminescence-mediated PDT for antitumors. This study paves the way for the design of chemiluminescent probes and their applications in the diagnosis and therapy of diseases.

Redox-Active Ferrocene Quencher-Based Supramolecular Nanomedicine for NIR-II Fluorescence-Monitored Chemodynamic Therapy

Real-time monitoring of hydroxyl radical (⋅OH) generation is crucial for both the efficacy and safety of chemodynamic therapy (CDT). Although ⋅OH probe-integrated CDT agents can track ⋅OH production by themselves, they often require complicated synthetic procedures and suffer from self-consumption of ⋅OH. Here, we report the facile fabrication of a self-monitored chemodynamic agent (denoted as Fc-CD-AuNCs) by incorporating ferrocene (Fc) into β-cyclodextrin (CD)-functionalized gold nanoclusters (AuNCs) via host-guest molecular recognition. The water-soluble CD served not only as a capping agent to protect AuNCs but also as a macrocyclic host to encapsulate and solubilize hydrophobic Fc guest with high Fenton reactivity for in vivo CDT applications. Importantly, the encapsulated Fc inside CD possessed strong electron-donating ability to effectively quench the second near-infrared (NIR-II) fluorescence of AuNCs through photoinduced electron transfer. After internalization of Fc-CD-AuNCs by cancer cells, Fenton reaction between redox-active Fc quencher and endogenous hydrogen peroxide (H2 O2 ) caused Fc oxidation and subsequent NIR-II fluorescence recovery, which was accompanied by the formation of cytotoxic ⋅OH and therefore allowed Fc-CD-AuNCs to in situ self-report ⋅OH generation without undesired ⋅OH consumption. Such a NIR-II fluorescence-monitored CDT enabled the use of renal-clearable Fc-CD-AuNCs for efficient tumor growth inhibition with minimal side effects in vivo.

A ferroptosis-reinforced nanocatalyst enhances chemodynamic therapy through dual H2O2 production and oxidative stress amplification

The existence of a delicate redox balance in tumors usually leads to cancer treatment failure. Breaking redox homeostasis by amplifying oxidative stress and reducing glutathione (GSH) can accelerate cancer cell death. Herein, we construct a ferroptosis-reinforced nanocatalyst (denoted as HBGL) to amplify intracellular oxidative stress via dual H2O2 production-assisted chemodynamic therapy (CDT). Specifically, a long-circulating liposome is employed to deliver hemin (a natural iron-containing substrate for Fenton reaction and ferroptosis), β-lapachone (a DNA topoisomerase inhibitor with H2O2 generation capacity for chemotherapy), and glucose oxidase (which can consume glucose for starvation therapy and generate H2O2). HBGL can achieve rapid, continuous, and massive H2O2 and •OH production and GSH depletion in cancer cells, resulting in increased intracellular oxidative stress. Additionally, hemin can reinforce the ferroptosis-inducing ability of HBGL, which is reflected in the downregulation of glutathione peroxidase-4 and the accumulation of lipid peroxide. Notably, HBGL can disrupt endo/lysosomes and impair mitochondrial function in cancer cells. HBGL exhibits effective tumor-killing ability without eliciting obvious side effects, indicating its clinical translation potential for synergistic starvation therapy, chemotherapy, ferroptosis therapy, and CDT. Overall, this nanocatalytic liposome may be a promising candidate for achieving potentiated cancer treatment.

Dual-Targeting Biomimetic Semiconducting Polymer Nanocomposites for Amplified Theranostics of Bone Metastasis

Bone metastasis is a type of metastatic tumors that involves the spreads of malignant tumor cells into skeleton, and its diagnosis and treatment remain a big challenge due to the unique tumor microenvironment. We herein develop osteoclast and tumor cell dual-targeting biomimetic semiconducting polymer nanocomposites (SPFeNOC ) for amplified theranostics of bone metastasis. SPFeNOC contain semiconducting polymer and iron oxide (Fe3 O4 ) nanoparticles inside core and surface camouflaged hybrid membrane of cancer cells and osteoclasts. The hybrid membrane camouflage enables their targeting to both metastatic tumor cells and osteoclasts in bone metastasis through homologous targeting mechanism, thus achieving an enhanced nanoparticle accumulation in tumors. The semiconducting polymer mediates near-infrared (NIR) fluorescence imaging and sonodynamic therapy (SDT), and Fe3 O4 nanoparticles are used for magnetic resonance (MR) imaging and chemodynamic therapy (CDT). Because both cancer cells and osteoclasts are killed synchronously via the combinational action of SDT and CDT, the vicious cycle in bone metastasis is broken to realize high antitumor efficacy. Therefore, 4T1 breast cancer-based bone metastasis can be effectively detected and cured by using SPFeNOC as dual-targeting theranostic nanoagents. This study provides an unusual biomimetic nanoplatform that simultaneously targets osteoclasts and cancer cells for amplified theranostics of bone metastasis.

Oxygen self-supplied nanoparticle for enhanced chemiexcited photodynamic therapy

Photodynamic therapy (PDT) is a promising strategy for effective cancer treatment. However, it still faces severe challenges, including poor laser penetration and insufficient oxygen (O2) in solid tumors. Here, we constructed intelligent O2self-supplied nanoparticles (NPs) for tumor hypoxia relief as well as effective chemiexcited PDT. Oxygen-carrying NPs (BSA@TCPO NPs) were obtained via the self-assembly of bovine serum albumin (BSA), bis[3,4,6-trichloro2-(pentyloxycarbonyl)phenyl]oxalate (TCPO), perfluorohexane (PFH), and chlorin e6 (Ce6). In H2O2-overexpressed tumor cells, TCPO in the NPs reacted with H2O2, releasing energy to activate the photosensitizer Ce6 and generate cytotoxic singlet oxygen (1O2) to kill tumor cells in a laser irradiation-independent manner. Moreover, the O2carried by PFH not only reduced therapeutic resistance by alleviating tumor hypoxia but also increased1O2generation for enhanced chemiexcited PDT. The remarkable cytotoxicity to various cancer cell lines and A549 tumors demonstrated the advantage of BTPC in alleviating the hypoxic status and inhibiting tumor growth. Our results demonstrate that BTPC is a promising nanoplatform for cancer therapy.

New Perylene-Based Chemiluminescent Polymer Nanoparticles for Highly Selective Detection of the Superoxide Anion In Vivo

The superoxide anion (O2•-) is one of the primary reactive oxygen species in biological systems. Developing a determination system for O2•- in vivo has attracted much attention thanks to its complex biological function. Herein, we proposed a new perylene-based chemiluminescence (CL) probe, the SH-PDI polymer, which was capable of generating strong CL signals with O2•- in comparison with other ROS. The CL mechanism involved was proposed to be a kind of oxidation reaction induced by the breakage of the S-S and S-H bonds into sulfoxide bonds by O2•-. Subsequently, a nanoprecipitation method was introduced, using cumene-terminated poly(styrene-co-maleic anhydride) as the amphiphilic agent, to obtain water-soluble nanoparticles, SPPS NPs, which exhibited not only stronger CL intensity but also higher selectivity toward O2•- than the SH-PDI polymer. Moreover, the CL wavelength of the SPPS-O2•- system was found to be located at 580 and 710 nm, which was conducive to CL imaging. By virtue of these advantages, SPPS NPs were utilized to evaluate the O2•- level in vitro in the range of 0.25-60 μM at pH 7.0, with a detection limit of 8.2 × 10-8 M (S/N = 3). Moreover, SPPS NPs were also capable of imaging O2•- in an LPS-induced acute inflammation mice model and drug-induced acute kidney injury (AKI).

Nanoprobe-based molecular imaging for tumor stratification

The responses of patients to tumor therapies vary due to tumor heterogeneity. Tumor stratification has been attracting increasing attention for accurately distinguishing between responders to treatment and non-responders. Nanoprobes with unique physical and chemical properties have great potential for patient stratification. This review begins by describing the features and design principles of nanoprobes that can visualize specific cell types and biomarkers and release inflammatory factors during or before tumor treatment. Then, we focus on the recent advancements in using nanoprobes to stratify various therapeutic modalities, including chemotherapy, radiotherapy (RT), photothermal therapy (PTT), photodynamic therapy (PDT), chemodynamic therapy (CDT), ferroptosis, and immunotherapy. The main challenges and perspectives of nanoprobes in cancer stratification are also discussed to facilitate probe development and clinical applications.

Unexcited Light Source Imaging for Biomedical Applications

Optical imaging has a wide range of applications in the biomedical field, allowing the visualization of physiological processes and helping in the diagnosis and treatment of diseases. Unexcited light source imaging technologies, such as chemiluminescence imaging, bioluminescence imaging and afterglow imaging have attracted great attention in recent years because of the absence of excitation light interference in their application and the advantages of high sensitivity and high signal-to-noise ratio. In this review, the latest advances in unexcited light source imaging technology for biomedical applications are highlighted. The design strategies of unexcited light source luminescent probes in improving luminescence brightness, penetration depth, quantum yield and targeting, and their applications in inflammation imaging, tumor imaging, liver and kidney injury imaging and bacterial infection imaging are introduced in detail. The research progress and future prospects of unexcited light source imaging for medical applications are further discussed.

Engineering a gold nanoparticles-carbon dots nanocomposite with pH-flexibility for monitoring hydrogen peroxide released from living cells

Constructing nanozymes with satisfactory catalytic efficiency under physiological conditions is still in great demand for facilitating the advancement of biocatalysts. We herein present a gold nanoparticles-carbon dots nanocomposite (Au-CDs) as an efficient photo-activated nanozyme for monitoring H2O2 released from living cells. The integration of CDs with AuNPs remarkably accelerates the catalytic activity at neutral pH via engaging Mn3+ ions as the mediators. Meanwhile, the reserved cyclodextrin cavities also enhance the adsorption capacity towards chromogenic substrates through host-guest interactions. Moreover, taking advantage of the inhibitory effect of H2O2 on the photo-oxidation ability of the Au-CDs nanocomposite, the Au-CDs based colorimetric method was able to realize in situ assessment of the hydrogen peroxide (H2O2) released from living cells. This method paves a new way to establish a promising biosensing platform for unraveling biological events.

Emerging biomedical imaging-based companion diagnostics for precision medicine

The tumor heterogeneity, which leads to individual variations in tumor microenvironments, causes poor prognoses and limits therapeutic response. Emerging technology such as companion diagnostics (CDx) detects biomarkers and monitors therapeutic responses, allowing identification of patients who would benefit most from treatment. However, currently, most US Food and Drug Administration-approved CDx tests are designed to detect biomarkers in vitro and ex vivo, making it difficult to dynamically report variations of targets in vivo. Various medical imaging techniques offer dynamic measurement of tumor heterogeneity and treatment response, complementing CDx tests. Imaging-based companion diagnostics allow for patient stratification for targeted medicines and identification of patient populations benefiting from alternative therapeutic methods. This review summarizes recent developments in molecular imaging for predicting and assessing responses to cancer therapies, as well as the various biomarkers used in imaging-based CDx tests. We hope this review provides informative insights into imaging-based companion diagnostics and advances precision medicine.

Recent development of pH-responsive theranostic nanoplatforms for magnetic resonance imaging-guided cancer therapy

The acidic characteristic of the tumor site is one of the most well-known features and provides a series of opportunities for cancer-specific theranostic strategies. In this regard, pH-responsive theranostic nanoplatforms that integrate diagnostic and therapeutic capabilities are highly developed. The fluidity of the tumor microenvironment (TME), with its temporal and spatial heterogeneities, makes noninvasive molecular magnetic resonance imaging (MRI) technology very desirable for imaging TME constituents and developing MRI-guided theranostic nanoplatforms for tumor-specific treatments. Therefore, various MRI-based theranostic strategies which employ assorted therapeutic modes have been drawn up for more efficient cancer therapy through the raised local concentration of therapeutic agents in pathological tissues. In this review, we summarize the pH-responsive mechanisms of organic components (including polymers, biological molecules, and organosilicas) as well as inorganic components (including metal coordination compounds, metal oxides, and metal salts) of theranostic nanoplatforms. Furthermore, we review the designs and applications of pH-responsive theranostic nanoplatforms for the diagnosis and treatment of cancer. In addition, the challenges and prospects in developing theranostic nanoplatforms with pH-responsiveness for cancer diagnosis and therapy are discussed.

A novel ROS-Related chemiluminescent semiconducting polymer nanoplatform for acute pancreatitis early diagnosis and severity assessment

Acute pancreatitis (AP) is a common and potentially life-threatening inflammatory disease of the pancreas. Reactive oxygen species (ROS) play a key role in the occurrence and development of AP. With increasing ROS levels, the degree of oxidative stress and the severity of AP increase. However, diagnosing AP still has many drawbacks, including difficulties with early diagnosis and undesirable sensitivity and accuracy. Herein, we synthesized a semiconducting polymer nanoplatform (SPN) that can emit ROS-correlated chemiluminescence (CL) signals. The CL intensity increased in solution after optimization of the SPN. The biosafety of the SPN was verified in vitro and in vivo. The mechanism and sensitivity of the SPN for AP early diagnosis and severity assessment were evaluated in three groups of mice using CL intensity, serum marker evaluations and hematoxylin and eosin staining assessments. The synthetic SPN can be sensitively combined with different concentrations of ROS to produce different degrees of high-intensity CL in vitro and in vivo. Notably, the SPN shows an excellent correlation between CL intensity and AP severity. This nanoplatform represents a superior method to assess the severity of AP accurately and sensitively according to ROS related chemiluminescence signals. This research overcomes the shortcomings of AP diagnosis in clinical practice and provides a novel method for the clinical diagnosis of pancreatitis in the future.

Reactive oxygen species in biological media are they friend or foe? Major In vivo and In vitro sensing challenges

The role of Reactive Oxygen Species (ROS) on biological media has been shifting over the years, as the knowledge on the complex mechanism that lies in underneath their production and overall results has been growing. It has been known for some time that these species are associated with a number of health conditions. However, they also participate in the immunoactivation cascade process, and can have an active role in theranostics. Macrophages, for example, react to the presence of pathogens through ROS production, potentially allowing the development of new therapeutic strategies. However, their short lifetime and limited spatial distribution of ROS have been limiting factors to the development and understanding of this phenomenon. Even though, ROS have shown successful theranostic applications, e.g., photodynamic therapy, their wide applicability has been hampered by the lack of effective tools for monitoring these processes in real time. Thus the development of innovative sensing strategies for in vivo monitoring of the balance between ROS concentration and the resultant immune response is of the utmost relevance. Such knowledge could lead to major breakthroughs towards the development of more effective treatments for neurodegenerative diseases. Within this review we will present the current understanding on the interaction mechanisms of ROS with biological systems and their overall effect. Additionally, the most promising sensing tools developed so far, for both in vivo and in vitro tracking will be presented along with their main limitations and advantages. This review focuses on the four main ROS that have been studied these are: singlet oxygen species, hydrogen peroxide, hydroxyl radical and superoxide anion.

Application of molecular dynamics simulation in self-assembled cancer nanomedicine

Self-assembled nanomedicine holds great potential in cancer theragnostic. The structures and dynamics of nanomedicine can be affected by a variety of non-covalent interactions, so it is essential to ensure the self-assembly process at atomic level. Molecular dynamics (MD) simulation is a key technology to link microcosm and macroscale. Along with the rapid development of computational power and simulation methods, scientists could simulate the specific process of intermolecular interactions. Thus, some experimental observations could be explained at microscopic level and the nanomedicine synthesis process would have traces to follow. This review not only outlines the concept, basic principle, and the parameter setting of MD simulation, but also highlights the recent progress in MD simulation for self-assembled cancer nanomedicine. In addition, the physicochemical parameters of self-assembly structure and interaction between various assembled molecules under MD simulation are also discussed. Therefore, this review will help advanced and novice researchers to quickly zoom in on fundamental information and gather some thought-provoking ideas to advance this subfield of self-assembled cancer nanomedicine.

Near-infrared absorbing semiconducting polymer nanomedicines for cancer therapy

As a new type of organic optical nanomaterials, semiconducting polymer nanoparticles (SPNs) have the advantages of good optical characteristics and photostability, low toxicity concerns, and relatively simple preparation processes. Particularly, near-infrared (NIR) absorbing SPNs have shown a great promise in biomedicine. In addition to acting as nanoprobes for molecular imaging, these SPNs can produce local heat and reactive oxygen species with the stimulation of NIR light, allowing photothermal therapy (PTT) and photodynamic therapy (PDT), respectively. Herein, we summarize the recent development of SPN-based nanomedicines for cancer therapy. The rational designs of SPNs for enhanced PTT, PDT, or combinational PTT/PDT to achieve effective ablation of tumor tissues are highlighted. Via loading/conjugating SPNs with other therapeutic elements (such as chemotherapeutic drugs and immunotherapeutic agents), phototherapy-combined chemotherapy or immunotherapy can be realized, which is then discussed. In especial, the constructions of SPN-based nanomedicines for NIR photoactivatable chemotherapy and immunotherapy are introduced with representative examples. Finally, we discuss the current challenges and key concerns of SPNs for their biomedical applications and give an outlook for their future clinical translation. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Hollow MnO2-Based Nanoprobes for Enhanced Photothermal/Photodynamic /Chemodynamic Co-Therapy of Hepatocellular Carcinoma

PURPOSE

The effect of monotherapy in cancer is frequently influenced by the tumor's unique hypoxic microenvironment, insufficient drug concentration at the treatment site, and tumour cells' increased drug tolerance. In this work, we expect to design a novel therapeutic nanoprobe with the ability to solve these problems and improve the efficacy of antitumor therapy.

METHODS

We have prepared a hollow manganese dioxide nanoprobes loaded with photosensitive drug IR780 for the photothermal/photodynamic/chemodynamic co-therapy of liver cancer.

RESULTS

The nanoprobe demonstrates efficient thermal transformation ability under a single laser irradiation, and under the synergistic influence of photo heat, accelerates the Fenton/ Fenton-like reaction efficiency based on Mn²⁺ ions to produce more ·OH under the synergistic effect of photo heat. Moreover, the oxygen released under the degradation of manganese dioxide further promotes the ability of photosensitive drugs to produce singlet oxygen (ROS). The nanoprobe has been found to efficiently destroy tumour cells in vivo and in vitro experiments when used in combination with photothermal/photodynamic/ chemodynamic modes of treatment under laser irradiation.

CONCLUSION

In all, this research shows that a therapeutic strategy based on this nanoprobe could be a viable alternative for cancer treatment in the near future.

Reagents for Mass Cytometry

Mass cytometry (cytometry by time-of-flight detection [CyTOF]) is a bioanalytical technique that enables the identification and quantification of diverse features of cellular systems with single-cell resolution. In suspension mass cytometry, cells are stained with stable heavy-atom isotope-tagged reagents, and then the cells are nebulized into an inductively coupled plasma time-of-flight mass spectrometry (ICP-TOF-MS) instrument. In imaging mass cytometry, a pulsed laser is used to ablate ca. 1 μm² spots of a tissue section. The plume is then transferred to the CyTOF, generating an image of biomarker expression. Similar measurements are possible with multiplexed ion bean imaging (MIBI). The unit mass resolution of the ICP-TOF-MS detector allows for multiparametric analysis of (in principle) up to 130 different parameters. Currently available reagents, however, allow simultaneous measurement of up to 50 biomarkers. As new reagents are developed, the scope of information that can be obtained by mass cytometry continues to increase, particularly due to the development of new small molecule reagents which enable monitoring of active biochemistry at the cellular level. This review summarizes the history and current state of mass cytometry reagent development and elaborates on areas where there is a need for new reagents. Additionally, this review provides guidelines on how new reagents should be tested and how the data should be presented to make them most meaningful to the mass cytometry user community.

Catalytically Active Metal-Organic Frameworks Elicit Robust Immune Response to Combination Chemodynamic and Checkpoint Blockade Immunotherapy

Chemodynamic therapy (CDT) strategies rely on the generation of reactive oxygen species (ROS) to kill tumor cells, with hydroxyl radicals (^•OH) serving as the key mediators of cytotoxicity in this setting. However, the efficacy of CDT approaches is often hampered by the properties of the tumor microenvironment (TME) and associated limitations to the Fenton reaction that constrains ROS generation. As such, there is a pressing need for the design of new nanoplatforms capable of improving CDT outcomes. In this study, an Fc-based metal-organic framework (MOF) vitamin k3 (Vk3)-loaded cascade catalytic nanoplatform (Vk3@Co-Fc) was developed. This platform was capable of undergoing TME-responsive degradation without impacting normal cells. After its release, Vk3 was processed by nicotinamide adenine dinucleotide hydrogen phosphate (NAD(P)H) quinone oxidoreductase-1 (NQO1), which is highly expressed in tumor cells, thereby yielding large quantities of H₂O₂ that in turn interact with Fe ions via the Fenton reaction to facilitate in situ cytotoxic ^•OH production. This process leads to immunogenic cell death (ICD) of the tumor, which then promotes dendritic cell maturation and ultimately increases T cell infiltration into the tumor site. When this nanoplatform was combined with programmed death 1 (PD-1) checkpoint blockade approaches, it was sufficient to enhance tumor-associated immune responses in breast cancer as evidenced by increases in the frequencies of CD45⁺ leukocytes and CD8⁺ cytotoxic T lymphocytes, thereby inhibiting tumor metastasis to the lungs and improving murine survival outcomes. Together, this Vk3@Co-Fc cascading catalytic nanoplatform enables potent cancer immunotherapy for breast cancer regression and metastasis prevention.

Semiconducting Polymer Dots for Point-of-Care Biosensing and In Vivo Bioimaging: A Concise Review

In recent years, semiconducting polymer dots (Pdots) have attracted much attention due to their excellent photophysical properties and applicability, such as large absorption cross section, high brightness, tunable fluorescence emission, excellent photostability, good biocompatibility, facile modification and regulation. Therefore, Pdots have been widely used in various types of sensing and imaging in biological medicine. More importantly, the recent development of Pdots for point-of-care biosensing and in vivo imaging has emerged as a promising class of optical diagnostic technologies for clinical applications. In this review, we briefly outline strategies for the preparation and modification of Pdots and summarize the recent progress in the development of Pdots-based optical probes for analytical detection and biomedical imaging. Finally, challenges and future developments of Pdots for biomedical applications are given.

Chemiluminescent polymeric nanoprobes for tumor diagnosis: A mini review

Chemiluminescence (CL), a distinct luminescent process by taking advantage of chemical reactions rather than external light source, has recently attracted considerable research interests due to its high sensitivity and low background signal. The sensitivity and specificity of chemiluminescent signals in complex tumor microenvironment provide a sound basis for accurate detection of tumors. Various chemiluminescent nanoprobes with superior performance have been obtained by structural modification of chemiluminescent units or introduction of fluorescent dyes. In this review, we focused on the recent progress of chemiluminescent polymeric systems based on various chromophore substrates, including luminol, peroxyoxalates, 1, 2-dioxetanes and their derivatives for tumor detecting. And we also emphasized the design strategies, mechanisms and diagnostic applications of representative chemiluminescent polymeric nanoprobes. Finally, the critical challenges and perspectives of chemiluminescent systems usage in tumor diagnosis were also discussed.

Research Progress of Nanomedicine-Based Mild Photothermal Therapy in Tumor

With the booming development of nanomedicine, mild photothermal therapy (mPTT, 42-45°C) has exhibited promising potential in tumor therapy. Compared with traditional PTT (>50°C), mPTT has less side effects and better biological effects conducive to tumor treatment, such as loosening the dense structure in tumor tissues, enhancing blood perfusion, and improving the immunosuppressive microenvironment. However, such a relatively low temperature cannot allow mPTT to completely eradicate tumors, and therefore, substantial efforts have been conducted to optimize the application of mPTT in tumor therapy. This review extensively summarizes the latest advances of mPTT, including two sections: (1) taking mPTT as a leading role to maximize its effect by blocking the cell defense mechanisms, and (2) regarding mPTT as a supporting role to assist other therapies to achieve synergistic antitumor curative effect. Meanwhile, the special characteristics and imaging capabilities of nanoplatforms applied in various therapies are discussed. At last, this paper puts forward the bottlenecks and challenges in the current research path of mPTT, and possible solutions and research directions in future are proposed correspondingly.

Selective Nanoblocker of Cellular Stress Response for Improved Drug-Free Tumor Therapy

Nanotechnology-based drug-free therapeutic systems using external stimuli can avoid the inherent side effects of drugs and become an attractive therapeutic strategy. However, the cellular stress responses (CSR) are activated encounter with external stimuli, which greatly weaken the efficacy of the drug-free antitumor. Thus, this work proposes a CSR regulation strategy and synthesizes the glucose oxidase (GOx)-modified Cu₃ BiS₃ nanosheets (CBSG NSs) encapsulated by calcium carbonate (CBSG@CaCO₃ ) as the novel drug-free nanoagent. The CBSG@CaCO₃ not only cause external stimuli such as energy consumption and oxidative stress damage, but also can destroy the CSR mechanism to guarantee optimal efficacy of starvation-chemodynamic therapy (ST-CDT). In tumor cells, the CaCO₃ shell layer of CBSG@CaCO₃ is rapidly degraded, releasing the slowly degradable CBSG NSs with NIR-II photothermal properties that accelerate the production of external stimuli under laser irradiation. Meanwhile, CaCO₃ can block CSR to disrupt the adaptive viability of cancer cells by inhibiting expression of P27 and NRF2. Importantly, the CSR regulation achieves selective treatment on tumor cells based on the difference in physiological conditions between cancer cells and normal cells. This drug-free cancer therapy with selectivity improves the problem of poor efficacy under the action of CSR, which offers a new avenue in the cancer-related disease treatment.

Organic persistent luminescence imaging for biomedical applications

Persistent luminescence is a unique visual phenomenon that occurs after cessation of excitation light irradiation or following oxidization of luminescent molecules. The energy stored within the molecule is released in a delayed manner, resulting in luminescence that can be maintained for seconds, minutes, hours, or even days. Organic persistent luminescence materials (OPLMs) are highly robust and their facile modification and assembly into biocompatible nanostructures makes them attractive tools for in vivo bioimaging, whilst offering an alternative to conventional fluorescence imaging materials for biomedical applications. In this review, we give attention to the existing limitations of each class of OPLM-based molecular bioimaging probes based on their luminescence mechanisms, and how recent research progress has driven efforts to circumvent their shortcomings. We discuss the multifunctionality-focused design strategies, and the broad biological application prospects of these molecular probes. Furthermore, we provide insights into the next generation of OPLMs being developed for bioimaging techniques.

Amorphous Ultra-Small Fe-Based Nanocluster Engineered and ICG Loaded Organo-Mesoporous Silica for GSH Depletion and Photothermal-Chemodynamic Synergistic Therapy

Intracellular oxidative amplification can effectively destroy tumor cells. Additionally, Fe-mediated Fenton reaction often converts cytoplasm H₂ O₂ to generate extensive hypertoxic hydroxyl radical (^• OH), leading to irreversible mitochondrion damage for tumor celleradication, which is widely famous as tumor chemodynamic therapy (CDT). Unfortunately, intracellular overexpressed glutathione (GSH) always efficiently scavenges ^• OH, resulting in the significantly reduced CDT effect. To overcome this shortcoming and improve the oxidative stress in cytoplasm, Fe₃ O₄ ultrasmall nanoparticle encapsulated and ICG loaded organo-mesoporous silica nanovehicles (omSN@Fe-ICG) are constructed to perform both photothermal and GSH depletion to enhance the Fenton-like CDT, by realizing intracellular oxidative stress amplification. After this nanoagents are internalized, the tetrasulfide bonds in the dendritic mesoporous framework can be decomposed with GSH to amplify the toxic ROS neration by selectively converting H₂ O₂ to hydroxyl radicals through the released Fe-based nanogranules. Furthermore, the NIR laser-induced hyperthermia can further improve the Fenton reaction rate that simultaneously destroyed the mitochondria. As a result, the GSH depletion and photothermal assisted CDT can remarkably improve the tumor eradication efficacy.

Meter-scale chemiluminescent carbon nanodot films for temperature imaging

Chemiluminescence (CL), as one class of luminescence driven by chemical reaction, exhibits obvious temperature-dependence in its light emission process. Herein, temperature-dependent CL emission of carbon nanodots (CDs) in the chemical reaction of peroxalate and hydrogen peroxide is demonstrated and temperature imaging based on the temperature-dependent CL has been established for the first time. In detail, the temperature-dependent CL emission of CDs in the chemical reaction of peroxalate and hydrogen peroxide is observed, and the linear relationship between the CL intensity and temperature is demonstrated in both the CL solution and film, enabling their applications in temperature sensing and imaging capabilities. The increase of the CL emission with temperature can be attributed to the accelerated electron exchange between the CDs and intermediate generated in the peroxalate system. Meter-scale chemiluminescent CD films have been constructed. The CL sensor based on the films presents a high spatial resolution of 0.4 mm and an outstanding sensitivity of 0.08 °C^-1, which is amongst the best values for the thermographic luminophores. With the unique temperature response and flexible properties, non-planar, meter-scale and sensitive palm temperature imaging has been achieved. These findings present new opportunities for designing CL-based temperature probes and thermography.

Emerging Biomaterials Imaging Antitumor Immune Response

Immunotherapy is one of the most promising clinical modalities for the treatment of malignant tumors and has shown excellent therapeutic outcomes in clinical settings. However, it continues to face several challenges, including long treatment cycles, high costs, immune-related adverse events, and low response rates. Thus, it is critical to predict the response rate to immunotherapy by using imaging technology in the preoperative and intraoperative. Here, the latest advances in nanosystem-based biomaterials used for predicting responses to immunotherapy via the imaging of immune cells and signaling molecules in the immune microenvironment are comprehensively summarized. Several imaging methods, such as fluorescence imaging, magnetic resonance imaging, positron emission tomography imaging, ultrasound imaging, and photoacoustic imaging, used in immune predictive imaging, are discussed to show the potential of nanosystems for distinguishing immunotherapy responders from nonresponders. Nanosystem-based biomaterials aided by various imaging technologies are expected to enable the effective prediction and diagnosis in cases of tumors, inflammation, and other public diseases.

Hemin-loaded black phosphorus-based nanosystem for enhanced photodynamic therapy and a synergistic photothermally/photodynamically activated inflammatory immune response

The biocompatible nanosystem integrating hemin into black phosphorus nanosheets was ingeniously constructed through the easy modified strategy. Taking advantage of the enhanced permeability and retention (EPR) effect, the designed nanosystem could accumulate into the tumor location, leading to attractive cytotoxicity through the enhanced photodynamic therapy (PDT) ascribing to the catalytic oxygen supply and GSH depletion of hemin. Simultaneously, combining PDT and photothermal therapy (PTT) showed an apparent promotion in anti-tumor effect. Moreover, inflammatory response and immune activation amplified anti-tumor effect, which could compensate limitations of exogenous therapy (i.e., limited tissue depth and intensity-dependent curation effect) and potentiate the efficiency of the endogenous immune-activating behavior. Especially, the designed nanosystem degraded followed by being metabolized in the blood circulation. By and large, this constructed nanosystem provides the new insight into designing biocompatible nanomaterials and paves the ideal way for anti-tumor therapy. STATEMENT OF SIGNIFICANCE: Biocompatible nanomaterials-based synergistic tumor therapy offers the potential application prospect. Taking advantage of degradable black phosphorus, the nanosystem integrating hemin into black phosphorus for the enhanced photodynamic therapy and synergistic photothermal-photodynamic activating inflammation-immune response was developed and the results demonstrate that tumor growth was inhibited followed by activating inflammatory factors and leading to satisfactory immune response.

Nanotrains of DNA Copper Nanoclusters That Triggered a Cascade Fenton-Like Reaction and Glutathione Depletion to Doubly Enhance Chemodynamic Therapy

Many current chemodynamic therapy (CDT) strategies suffer from either low therapeutic efficiency or the deficiency of poor targeting. The low therapeutic efficiency is mainly ascribed to the intracellular antioxidant system and the inefficient Fenton reaction in the weakly acidic tumor microenvironment (TME). Herein, by exploitation of the diverse function and programmability of functional nucleic acid, aptamer-tethered nanotrains of DNA copper nanoclusters (aptNTDNA-CuNCs) were assembled to simultaneously achieve targeted recognition, loading, and delivery of CDT reagents into tumor cells without an external carrier. The intracellular hydrogen peroxide (H₂O₂) oxidized nanotrains of DNA-CuNCs to produce a lot of Cu²⁺ and Cu⁺ ions, which can generate reactive oxygen species (ROS) in the weakly acidic TME based on the pH-independent Fenton-like reaction of Cu⁺/H₂O₂. Meanwhile, the redox reaction between intracellular glutathione (GSH) and Cu²⁺ depleted GSH and generated Cu⁺ ions, which weakened the antioxidant ability of cancer cells and further enhanced the Fenton-like reaction of Cu⁺/H₂O₂, respectively. Thus, the cascade Fenton-like reaction and GSH depletion doubly improved the efficacy of CDT. The in vivo and in vitro study solidly confirmed that aptNTDNA-CuNCs have excellent antitumor efficacy and no cytotoxicity to healthy cells. Therefore, aptNTDNA-CuNCs can act as CDT reagents to achieve highly efficient, biocompatible, and targeted CDT.

Supramolecular Self-Assemblies with Self-Supplying H2O2 and Self-Consuming GSH Property for Amplified Chemodynamic Therapy

Fe-based chemodynamic therapy (CDT) has become one potential method for cancer therapy due to its lower side effect and tumor-specific property. During the process of CDT, the lack of active targeting and biodegradable ability, insufficient endogenous H₂O₂, and overexpressed GSH in the tumor were responsible for the unsatisfactory therapeutic performance. Hence, we report host-guest interaction-based supramolecular polymers (HGSPs) that were constructed with the biomacromolecule β-cyclodextrin-grafted hyaluronic acid (HA-CD) as the active targeting host unit and hydrophobic ROS-responsive ferrocene-(phenylboronic acid pinacol ester) (Fc-BE) as the guest unit. HGSPs can further self-assemble into self-assemblies (HGSAs) and encapsulate PA as the prooxidant. After CD44-receptor-mediated cellular internalization, HGSAs could disassemble and release PA to elevate the H₂O₂ level for the production of higher cytotoxic hydroxyl radicals (^•OH) through the Fc-induced Fenton reaction. Moreover, quinone methide (QM) was generated to downregulate antioxidant GSH. The enhancement of H₂O₂ and consumption of GSH were favorable for CDT due to the amplified oxidative stress. In vivo experimental results indicated that HGSAs@PA might be used as an active targeting amplified CDT agent.

Synergetic Dual-Site Atomic Catalysts for Sensitive Chemiluminescent Immunochromatographic Test Strips

In view of the outstanding catalytic efficiency, single-atom catalysts (SACs) have shown great promise for the construction of sensitive chemiluminescent (CL) platforms. However, the low loading amount of active sites dramatically obstructs the improved catalytic activity of these metal SACs. Benefiting from the exceedingly unique catalytic properties of the metal-metal bonds, atomic clusters may give rise to enhancing the catalytic properties of SACs based on the synergistic effects of dual atomic-scale sites. Inspired by this, atomic Co₃N clusters-assisted Co SACs (Co₃N@Co SACs) were synthesized through a facile doping method. Through X-ray absorption spectroscopy, the active metal sites in the synergetic dual-site atomic catalysts of Co₃N@Co SACs were confirmed to be Co-O₄ and Co₃-N moieties. Co₃N@Co SACs served as a superior co-reactant to remarkably enhance the luminol CL signal by 2155.0 times, which was prominently superior to the boosting effect of the pure Co SACs (98.4 times). The synergetic dual-site atomic catalysts contributed to accelerating the decomposition of H₂O₂ into singlet oxygen as well as superoxide radical anions to display superb catalytic performances. For a concept employment, Co₃N@Co SACs were attempted to utilize as CL probes for establishing a sensitive immunochromatographic assay to quantitate pesticide residues, in which imidacloprid was adopted as the model analyte. The quantitative range of imidacloprid was 0.05-10 ng mL^-1 with a detection limit of 1.7 pg mL^-1 (3σ). Furthermore, the satisfactory recovery values in mock herbal medicine samples demonstrated the effectiveness of the proposed Co₃N@Co SAC-based CL platform. In the proof-of-concept work, synergetic dual-site atomic catalysts show great perspectives on trace analysis and luminescent biosensing.

Mussel-inspired multifunctional hydrogel dressing with hemostasis, hypoglycemic, photothermal antibacterial properties on diabetic wounds

To meticulously establish an efficient photothermal multifunctional hydrogel dressing is a prospective strategy for the treatment of diabetic chronic wounds. Herein, glucose oxidase (GOx) was added to polydopamine/acrylamide (PDA/AM) hydrogels to reduce hyperglycemia to a normal level (3.9-6.1 mmol L^-1) and enhance compressive properties (55 kPa) and adhesive properties (32.69 kPa), which are capable of hemostasis in the wound. Then, MnO₂ nanoparticles were encapsulated into a polydopamine/acrylamide (PDA/AM) hydrogel, endowing it with excellent antibacterial properties (E. coli and S. aureus were 97.87% and 99.99%) under the irradiation of 808 nm NIR; meanwhile, the biofilm was eliminated completely. Besides, O₂ was generated (18 mg mL^-1) by the decomposition of H₂O₂ under the catalysis of MnO₂, which could accelerate the formation of angiogenesis and promote the crawling and proliferation of cells. Furthermore, the diabetic wound in vivo treated with the PDA/AM/GOx/MnO₂ hydrogel had a less inflammatory response and faster healing speed, which was completely healed in 14 days. Therefore, the multifunctional hydrogels with the capability of high compressible, hemostasis, antibacterial, hyperglycemia manipulation, and O₂ generation, demonstrate promise in diabetic chronic wound dressing.

Applications of Magnetic Particle Imaging in Biomedicine: Advancements and Prospects

Magnetic particle imaging (MPI) is a novel emerging noninvasive and radiation-free imaging modality that can quantify superparamagnetic iron oxide nanoparticles tracers. The zero endogenous tissue background signal and short image scanning times ensure high spatial and temporal resolution of MPI. In the context of precision medicine, the advantages of MPI provide a new strategy for the integration of the diagnosis and treatment of diseases. In this review, after a brief explanation of the simplified theory and imaging system, we focus on recent advances in the biomedical application of MPI, including vascular structure and perfusion imaging, cancer imaging, the MPI guidance of magnetic fluid hyperthermia, the visual monitoring of cell and drug treatments, and intraoperative navigation. We finally optimize MPI in terms of the system and tracers, and present future potential biomedical applications of MPI.

Near Infrared-Triggered Theranostic Nanoplatform with Controlled Release of HSP90 Inhibitor for Synergistic Mild Photothermal and Enhanced Nanocatalytic Therapy with Hypoxia Relief

Mild photothermal therapy (PTT, <45 °C) can prevent tumor metastasis and heat damage to normal tissue, compared with traditional PTT (>50 °C). However, its therapeutic efficacy is limited owing to the hypoxic tumor environment and tumor thermoresistance owing to the overproduction of heat shock proteins (HSPs). Herein, a near-infrared (NIR)-triggered theranostic nanoplatform (GA-PB@MONs@LA) is designed for synergistic mild PTT and enhanced Fenton nanocatalytic therapy against hypoxic tumors. The nanoplatform is fabricated by the confined formation of Prussian blue (PB) nanoparticles in mesoporous organosilica nanoparticles (MONs), followed by the loading of gambogic acid (GA), an HSP90 inhibitor, and coating with thermo-sensitive lauric acid (LA). Upon NIR irradiation, the photothermal effect (44 °C) of PB not only induces apoptosis of tumor cells but also triggers the on-demand release of GA, inhibiting the production of HSP90. Moreover, the delivered heat simultaneously enhances the catalase-like and Fenton activity of PB@MONs@LA in an acidic tumor microenvironment, relieving the tumor hypoxia and promoting the generation of highly toxic •OH. In addition, the nanoplatform enables magnetic resonance/photoacoustic dual-modal imaging. Thus, this study describes a distinctive paradigm for the development of NIR-triggered theranostic nanoplatforms for enhanced cancer therapy.

Ultrasound-triggered reactive oxygen species effector nanoamplifier for enhanced combination therapy of mutant p53 tumors

Reactive oxygen species (ROS) damage is a crucial method with which to inhibit tumor cell proliferation; however, tumor cells can reduce ROS damage by modulating multiple repair mechanisms, thus, reducing the efficacy of ROS damage in tumor therapy. In this study, we built an ultrasound-triggered ROS damage nanoamplifier using a synergistic strategy consisting of ROS damage and decreased tumor self-protection capability to enhance the treatment efficacy of mutant p53 tumors. A ROS damage nanoamplifier (PT@PTGA) was fabricated using amphiphilic polyglutamic acid (PTGA) to load with a sonosensitizer (protoporphyrin IX, PpIX) and an MTH1 inhibitor (TH287). Under ultrasonic excitation, PpIX catalyzes oxygen to produce singlet oxygen and release TH287 to inhibit MTH1 activity, thereby causing the accumulation of 8-oxo-dGTP, which enhances DNA damage and further induces cell apoptosis. In addition, TH287 allies with ROS to eliminate the mutated p53 protein in tumor cells, thus reducing the self-protective capacity of tumor cells. As a result, the "internal and external" aspects were combined to enhance sensitization for mutant p53 tumor therapy. The construction of a ROS nanoamplifier not only provides an effective strategy for the treatment of mutant p53 tumors but also supplies an integrated platform for tumor diagnosis and therapy.

A bright chemiluminescence conjugated polymer-mesoporous silica nanoprobe for imaging of colonic tumors in vivo

Hypochlorite acid (ClO^-) is one of the major reactive oxygen species (ROS) in colon cancer, providing an effective target for colonic tumor in vivo imaging. For detection of ClO^- and tumor imaging, poly[(9,9-di(2-ethylhexyl)-9H-fluorene-2,7-vinylene)-co-(1-methoxy-4-(2-ethylhexyloxy)-2,5-phenylenevinylene)] (PFV-co-MEHPV, namely CP1) was encapsulated in mesoporous silica nanoparticles (MSNs) that were pre-modified with polyphenylenevinylene (PPV) via in situ polymerization to construct bright PPV@MSN-CP1 nanoparticles. The synthesized nanoparticles were size-stable and not cytotoxic as confirmed by FE-TEM, FE-SEM, and MTT assay. Hypochlorite oxidizes the vinylidene bond of CP1 through π²-π² cycloaddition to form PPV-dioxetane intermediates to generate photons. The CL quantum yield of PPV@MSN-CP1 was 16.7 times higher than that of Pluronic F-127 wrapped CP1. CL nanoparticles PPV@MSN-CP1 have good selectivity for hypochlorite detection among biological oxidants (mainly ROS). The linear range and the LOD of PPV@MSN@CP1 for ClO^- detection are 4-90 and 1.02 μM, respectively. Subsequently, we further coated PPV@MSN@CP1 with folic acid for tumor targeting by phospholipid wrapping. PPV@MSN-CP1@FA was successfully applied for in vivo imaging of endogenously produced ClO^- of tumor tissue in living animals.