Aggregation of Gold Nanoparticles Triggered by Hydrogen Peroxide-Initiated Chemiluminescence for Activated Tumor Theranostics

1D, 3D supramolecular assemblies of a series of cyclometalated platinum(II) complexes with deep-red aggregation-induced phosphorescent emission and anion turn-on sensing via Pt-Pt interaction

Controlling the size and morphology of supramolecular assemblies is still an enormous challenge for the development of novel functional materials. Herein, cyclometalated platinum(II) complexes were designed and used as effective theragnostic supramolecular nano agents. Benzoquinoline was used as the main C^N ligand, and the increased number of aromatic rings in the N^N ligand of Pt complexes could greatly improve lipophilicity and cytotoxicity towards cancer cells over normal cells. Moreover, the morphology of nanoparticles formed by self-assembly of Pta-d could change from one to three-dimensional (1-3D), which can form nanowires and nanospheres. Besides, complexes of Pta-c, the number of aromatic rings in the N^N ligand of which does not exceed 4, all exhibit significant aggregation-induced phosphorescent emission (AIPE) with 100 - 200-fold enhancement in red phosphoresce intensity recorded in the solvent of Pta-1 and Ptb. Pt-Pt interaction induced by coordination and electrostatic interaction between complex and anions, and a new deep red emission improvement was observed in aqueous solution of Pta and Ptb with the presence of ClO4-, and two similar deep red emissions induced by two different interactions can be told by new emerging MMLCT absorption band. Ptd of dppz ligand exhibits the highest efficiency in inducing apoptosis of HeLa and its anticancer mechanism was studied. Our work aims to promote the fundamental comprehension of the self-assembly behavior of cyclometalated platinum complex with AIPE in vitro and living cells.

Nanoparticle-protein interactions: Spectroscopic probing of the adsorption of serum albumin to graphene oxide‑gold nanocomplexes surfaces

Graphene oxide‑gold nanocomposites (GO-AuNCPs) are promising candidates in nanomedicine. They will inevitably bind with biomolecules such as serum albumin (SA) in the body while they enter the organism. The interaction between GO-AuNCPs and human serum albumin (HSA)/bovine serum albumin (BSA) were investigated by using multispectroscopic methods, elucidating the binding principles through molecular simulations. The results of ultraviolet-visible (UV-vis) absorption spectroscopy and steady-state fluorescence spectroscopy indicated that GO-AuNCPs interacted with HSA/BSA with different degrees of interaction. The binding of GO-AuNCPs and HSA/BSA was a spontaneous endothermic reaction, and the quenching mechanism is static quenching. The binding constant (Ka) value of BSA binding to GO-AuNCPs at the same temperature was greater than that for HSA, indicating a stronger affinity of BSA for GO-AuNCPs. Molecular simulation revealed that the binding sites of GO-AuNCPs on HSA/BSA were located within the slits of the subdomains IB and IIIA, rather than within any known binding regions. This significant finding was validated by using of site markers phenylbutazone (PB) and flufenamic acid (FA). Synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, and circular dichroism (CD) spectroscopy showed that the conformation of HSA/BSA was altered upon the addition of GO-AuNCPs, resulting in slight structural changes of tryptophan and tyrosine residues. Although the secondary structure of HSA/BSA was changed, the α-helix remained dominant. The results provide a theoretical and experimental foundation for developing of safe and effective nanomaterials, which is of great theoretical significance.

An ingenious chemiluminescence sensing strategy for recalcitrant triphenyl phosphate based on oxidant-free UV-activated MIL-100(Fe) gel system

BACKGROUND

Organophosphate flame retardants (OPFRs) are notorious emerging contaminants threatening the environment and human health. Triphenyl phosphate (TPHP), which has an extremely serious biotoxicity, is a typical harmful OPFR. Due to its wide use, TPHP has been discovered in various environmental mediums. Moreover, it is pretty recalcitrant to the removal process, resulting in the need for a technique to understand it better. Hence, accurate and quick discrimination of TPHP in the environment is critical to further evaluate its potential effect on ecosystems and human health.

RESULTS

An ingenious oxidant-free chemiluminescence (CL) sensor based on the oxidant-free UV/MIL-100(Fe) gel system was established for TPHP detection. The oxidation of luminol in the UV-activated MIL-100(Fe) gel has resulted in remarkable CL emission, which is contributed by reactive oxygen species (ROS) generated by it. Notably, the CL intensity was inhibited significantly after introducing TPHP. An investigation into the mechanism underlying the effect of CL suppression demonstrated that TPHP competed with luminol to consume ROS from UV-activated MIL-100(Fe) gel, contributing to CL inhibition. The subsequent sensing performance experiments demonstrated the advantages of environmentally friendly, economic efficiency, user-friendly operation, rapid determination, potential for compact size, high selectivity, and sensitivity. Additionally, these investigations confirmed the low limit of detection (210 ng L-1) and wide linear range (10-1000 μg L-1).

SIGNIFICANCE

In this paper, a green, economical, and oxidant-free CL sensing strategy for TPHP has been established. It has the advantage of being rapid, having the potential for compact size, high selectivity, and sensitivity. This ingenious method has promising applications in real-time and online environmental monitoring, and it paves the way for the rapid and environmentally friendly identification of emerging contaminants that are structurally stable and recalcitrant to remove.

Atomically Fe(Ⅲ) anchored metal-organic frameworks-based fluorescent nanozyme for smartphone-adopted chemiluminescence-fluorescence dual-mode analysis of Uric acid

BACKGROUND

Chemiluminescence (CL) analysis is a promising analytical method with advantages including easy operation, high sensitivity and simple instrument. However, the single CL mode usually suffered from poor stability and reproducibility as a result of the flash-type nature of luminescent molecules, leading to false positive or negative results in practical applications. Dual-mode detection is an advanced sensing methodology that identifies analytes through independent output signals. This approach has the ability to circumvent the inherent constraints of individual sensing modes while integrating their respective strengths, thereby yielding a synergistic enhancement in the detection system.

RESULTS

Herein, a chemiluminescence-fluorescence (FL) dual-mode analysis and imaging system is designed by constructing an atomically Fe(Ⅲ) anchored PCN-224 peroxidase-mimicking nanozyme (PCN-224/Fe(Ⅲ)) and achieve an ultrasensitive detection of Uric Acid (UA). The multifunctional PCN-224/Fe(Ⅲ) serves as a high-efficiency co-reaction promoter in the generation of reactive oxygen species (ROS) in both the CL and FL system, while also demonstrating exceptional capabilities as fluorescent nanoprobes. Ultimately, a smartphone-adopted CL imaging device was developed to achieve a visual CL detection through the design of portable paper-based chips. Besides, with the assistance of the TMB-mediated fluorescence energy resonance transfer, the fluorescent PCN-224/Fe(Ⅲ) nanoprobes exhibited good fluorescence detection performance for UA. The limit of detection was achieved as low as 2.45 × 10-10 M and 1.99 × 10-9 M in the CL and FL mode, respectively.

SIGNIFICANCE

This study engineered an atomically Fe(Ⅲ)- MOF-based multifunctional nanozyme and developed an innovative approach for creating CL-FL dual-mode analysis and imaging detection for UA. The proposed CL-FL dual-mode detection system not only provided a portable and sensitive method for UA detection but also offered valuable insights into the mechanism of the co-reaction promoter enhanced CL and FL analysis.

Proximal Anchoring of Nanodrugs through In Situ Generated Radical Hooks with Boosted Autophagy and Immunotherapy

Efficient retention of drugs at tumor sites was always desirable to maximize therapeutic functions, yet the main concern is the dynamic blood clearance induced fast removal from localized lesion. Herein, a tumor microenvironment activated covalently conjugation (self- and proximal conjugation) of tyramine modified Pt nanoclusters (PCMT NPs) was constructed by in situ produced radical hooks, leading to efficient accumulation of PCMT NPs at tumor sites. Such accumulation further aggravated the oxidative stress and provoked autophagy of tumor cells via activating the caspase-3 pathway mediated massive apoptosis, thereby stimulating immunogenic cell death (ICD). As verified by in vivo results, the PCMT NPs effectively suppressed primary and distant tumor growth (with an inhibition rate of 99%) while eliciting immunotherapeutic responses. As such, a new paradigm for boosting drug retention was provided, which enabled specific tumor treatment with synergistic therapeutic outcomes.

Facile synthesis of EGCG modified Au nanoparticles and their inhibitory effects on amyloid protein aggregation

Preventing β-amyloid (Aβ) peptide aggregation by Au nanoparticles (NPs) is a promising strategy for the treatment of Alzheimer's disease. However, construction of Au nanostructures with easy preparation and high therapeutic efficiency is still a challenge. Herein, one-step pulsed laser ablation in water is used to fabricate epigallocatechin-3-gallate (EGCG) modified Au (Au-EGCG) NPs with uniform size. The as-obtained Au-EGCG NPs can effectively inhibit β-amyloid (1-42) peptide (Aβ42) aggregation by the interaction with peptides, which is confirmed by transmission electron microscopy (TEM), fluorescence spectroscopy (thioflavin T (ThT), tyrosine and 8-anilinonaphthalene-1-sulfonic acid (ANS) assays), and Fourier transform infrared (FT-IR) spectroscopy. Besides, they can also effectively attenuate Aβ42-induced cytotoxicity based on the cell viability experiments. This work provides a facile approach to synthesize the surface-functionalized Au NPs for enhanced inhibition of Aβ aggregation and amelioration of Aβ-induced cytotoxicity.

Functional inorganic nanoparticles in cancer: Biomarker detection, imaging, and therapy

Cancer poses a major global public health challenge. Developing more effective early diagnosis methods and efficient treatment techniques is crucial to enhance early detection sensitivity and treatment outcomes. Nanomaterials offer sensitive, accurate, rapid, and straightforward approaches for cancer detection, diagnosis, and treatment. Inorganic nanoparticles are widely used in medicine because of their high stability, large specific surface area, unique surface properties, and unique quantum size effects. Functional inorganic nanoparticles involve modifying inorganic nanoparticles to enhance their physical properties, enrichment capabilities, and drug-loading efficiency and to minimize toxicity. This Review provides an overview of various types of inorganic nanoparticles and their functionalization characteristics. We then discuss the progress of functional inorganic nanoparticles in cancer biomarker detection and imaging. Furthermore, we discuss the application of functional inorganic nanoparticles in radiotherapy, chemotherapy, gene therapy, immunotherapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and combination therapy, highlighting their characteristics and advantages. Finally, the toxicity and potential challenges of functional inorganic nanoparticles are analyzed. The purpose of this Review is to explore the application of functional inorganic nanoparticles in diagnosing and treating cancers, while also presenting a new avenue for cancer diagnosis and treatment.

Turning foes to friends: Advanced "in situ nanovaccine" with dual immunoregulation for enhanced immunotherapy of metastatic triple-negative breast cancer

As a "cold tumor", triple-negative breast cancer (TNBC) exhibits limited responsiveness to current immunotherapy. How to enhance the immunogenicity and reverse the immunosuppressive microenvironment of TNBC remain a formidable challenge. Herein, an "in situ nanovaccine" Au/CuNDs-R848 was designed for imaging-guided photothermal therapy (PTT)/chemodynamic therapy (CDT) synergistic therapy to trigger dual immunoregulatory effects on TNBC. On the one hand, Au/CuNDs-R848 served as a promising photothermal agent and nanozyme, achieving PTT and photothermal-enhanced CDT against the primary tumor of TNBC. Meanwhile, the released antigens and damage-associated molecular patterns (DAMPs) promoted the maturation of dendritic cells (DCs) and facilitated the infiltration of T lymphocytes. Thus, Au/CuNDs-R848 played a role as an "in situ nanovaccine" to enhance the immunogenicity of TNBC by inducing immunogenic cell death (ICD). On the other hand, the nanovaccine suppressed the myeloid-derived suppressor cells (MDSCs), thereby reversing the immunosuppressive microenvironment. Through the dual immunoregulation, "cold tumor" was transformed into a "hot tumor", not only implementing a "turning foes to friends" therapeutic strategy but also enhancing immunotherapy against metastatic TNBC. Furthermore, Au/CuNDs-R848 acted as an excellent nanoprobe, enabling high-resolution near-infrared fluorescence and computed tomography imaging for precise visualization of TNBC. This feature offers potential applications in clinical cancer detection and surgical guidance. Collectively, this work provides an effective strategy for enhancing immune response and offers novel insights into the potential clinical applications for tumor immunotherapy.

Light-Activated In Situ Vaccine with Enhanced Cytotoxic T Lymphocyte Infiltration and Function for Potent Cancer Immunotherapy

In situ cancer vaccination is an attractive strategy that stimulates protective antitumor immunity. Cytotoxic T lymphocytes (CTLs) are major mediators of the adaptive immune defenses, with critical roles in antitumor immune response and establishing immune memory, and are consequently extremely important for in situ vaccines to generate systemic and lasting antitumor efficacy. However, the dense extracellular matrix and hypoxia in solid tumors severely impede the infiltration and function of CTLs, ultimately compromising the efficacy of in situ cancer vaccines. To address this issue, a robust in situ cancer vaccine, Au@MnO2 nanoparticles (AMOPs), based on a gold nanoparticle core coated with a manganese dioxide shell is developed. The AMOPs modulated the unfavorable tumor microenvironment (TME) to restore CTLs infiltration and function and efficiently induced immunogenic cell death. The Mn2+-mediated stimulator of the interferon genes pathway can be activated to further augment the therapeutic efficacy of the AMOPs. Thus, the AMOPs vaccine successfully elicited long-lasting antitumor immunity to considerably inhibit primary, recurrent, and metastatic tumors. This study not only highlights the importance of revitalizing CTLs efficacy against solid tumors but also makes progress toward overcoming TME barriers for sustained antitumor immunity.

Aggregable gold nanoparticles for cancer photothermal therapy

Photothermal therapy (PTT) is an important non-invasive cancer treatment method. Enhancing the photothermal conversion efficiency (PCE) of photothermal agents (PTAs) and prolonging their tumor accumulation and retention are effective strategies to enhance the efficiency of cancer PTT. Recently, tremendous progress has been made in developing stimuli-responsive aggregable gold nanoparticles as effective PTAs for PTT. In this review, we discuss the chemical principles underlying gold nanoparticle aggregation and highlight the progress in gold nanoparticle aggregation triggered by different stimuli, especially tumor microenvironment-related factors, for cancer PTT. Covalent condensation reactions, click cycloaddition reactions, chelation reactions, and Au-S bonding, as well as non-covalent electrostatic interactions, hydrophobic interactions, hydrogen bonding, and van der Waals forces play key roles in the aggregation of gold nanoparticles. Enzymes, pH, reactive oxygen species, small molecules, salts, and light drive the occurrence of gold nanoparticle aggregation. Targeted aggregation of gold nanoparticles prolongs tumor accumulation and retention of PTAs and improves PCE, resulting in enhanced tumor PTT. Moreover, the major challenges of aggregable gold nanoparticles as PTAs are pointed out and the promising applications are also prospected at the end. With the deepening of research, we expect aggregable gold nanoparticles to become essential PTAs for tumor therapy.

S-Sulfenylation Driven Antigen Capture Boosted by Radiation for Enhanced Cancer Immunotherapy

Radiotherapy (RT)-induced in situ vaccination greatly promotes the development of personalized cancer vaccines owing to the massive release of antigens initiated by tumor-localized RT eliciting the tumor-specific immune response. However, its broad application in cancer treatment is seriously impeded by poor antigen cross-presentation, low response rate, and short duration of efficacy. Herein, the tumor-antigen-capturing nanosystem dAuNPs@CpG consisting of gold nanoparticles, 3,5-cyclohexanedione (CHD), and immunoadjuvant CpG were fabricated to enhance RT-induced vaccination. Taking advantage of the specific covalent binding between CHD and sulfenic acids of antigen proteins, we show that this nanoplatform has an unexpected potential to capture the sulfenylated tumor-derived protein antigens (TDPAs) induced by RT to in situ generate a vaccination effect, achieving significant growth suppression of both primary and distant tumors in combination with PD-1 blockade. We thus believe that our work presents a powerful and effective means to improve the synergistic tumor radioimmunotherapy.

Cerium Dioxide-Dextran Nanocomposites in the Development of a Medical Product for Wound Healing: Physical, Chemical and Biomedical Characteristics

PURPOSE OF THE STUDY

the creation of a dextran coating on cerium oxide crystals using different ratios of cerium and dextran to synthesize nanocomposites, and the selection of the best nanocomposite to develop a nanodrug that accelerates quality wound healing with a new type of antimicrobial effect.

MATERIALS AND METHODS

Nanocomposites were synthesized using cerium nitrate and dextran polysaccharide (6000 Da) at four different initial ratios of Ce(NO3)3x6H2O to dextran (by weight)-1:0.5 (Ce0.5D); 1:1 (Ce1D); 1:2 (Ce2D); and 1:3 (Ce3D). A series of physicochemical experiments were performed to characterize the created nanocomposites: UV-spectroscopy; X-ray phase analysis; transmission electron microscopy; dynamic light scattering and IR-spectroscopy. The biomedical effects of nanocomposites were studied on human fibroblast cell culture with an evaluation of their effect on the metabolic and proliferative activity of cells using an MTT test and direct cell counting. Antimicrobial activity was studied by mass spectrometry using gas chromatography-mass spectrometry against E. coli after 24 h and 48 h of co-incubation.

RESULTS

According to the physicochemical studies, nanocrystals less than 5 nm in size with diffraction peaks characteristic of cerium dioxide were identified in all synthesized nanocomposites. With increasing polysaccharide concentration, the particle size of cerium dioxide decreased, and the smallest nanoparticles (<2 nm) were in Ce2D and Ce3D composites. The results of cell experiments showed a high level of safety of dextran nanoceria, while the absence of cytotoxicity (100% cell survival rate) was established for Ce2D and C3D sols. At a nanoceria concentration of 10-2 M, the proliferative activity of fibroblasts was statistically significantly enhanced only when co-cultured with Ce2D, but decreased with Ce3D. The metabolic activity of fibroblasts after 72 h of co-cultivation with nano composites increased with increasing dextran concentration, and the highest level was registered in Ce3D; from the dextran group, differences were registered in Ce2D and Ce3D sols. As a result of the microbiological study, the best antimicrobial activity (bacteriostatic effect) was found for Ce0.5D and Ce2D, which significantly inhibited the multiplication of E. coli after 24 h by an average of 22-27%, and after 48 h, all nanocomposites suppressed the multiplication of E. coli by 58-77%, which was the most pronounced for Ce0.5D, Ce1D, and Ce2D.

CONCLUSIONS

The necessary physical characteristics of nanoceria-dextran nanocomposites that provide the best wound healing biological effects were determined. Ce2D at a concentration of 10-3 M, which stimulates cell proliferation and metabolism up to 2.5 times and allows a reduction in the rate of microorganism multiplication by three to four times, was selected for subsequent nanodrug creation.

Physiological Microenvironment Dependent Self-Cross-Linking of Multifunctional Nanohybrid for Prolonged Antibacterial Therapy via Synergistic Chemodynamic-Photothermal-Biological Processes

Herein, a multifunctional nanohybrid (PL@HPFTM nanoparticles) was fabricated to perform the integration of chemodynamic therapy, photothermal therapy, and biological therapy over the long term at a designed location for continuous antibacterial applications. The PL@HPFTM nanoparticles consisted of a polydopamine/hemoglobin/Fe2+ nanocomplex with comodification of tetrazole/alkene groups on the surface as well as coloading of antimicrobial peptides and luminol in the core. During therapy, the PL@HPFTM nanoparticles would selectively cross-link to surrounding bacteria via tetrazole/alkene cycloaddition under chemiluminescence produced by the reaction between luminol and overexpressed H2O2 at the infected area. The resulting PL@HPFTM network not only significantly damaged bacteria by Fe2+-catalyzed ROS production, effective photothermal conversion, and sustained release of antimicrobial peptides but dramatically enhanced the retention time of these therapeutic agents for prolonged antibacterial therapy. Both in vitro and in vivo results have shown that our PL@HPFTM nanoparticles have much higher bactericidal efficiency and remarkably longer periods of validity than free antibacterial nanoparticles.

mRNA-responsive two-in-one nanodrug for enhanced anti-tumor chemo-gene therapy

The combination of chemotherapy and gene therapy holds great promise for the treatment and eradication of tumors. However, due to significant differences in physicochemical properties between chemotherapeutic agents and functional nucleic acid drugs, direct integration into a single nano-agent is hindered, impeding the design and construction of an effective co-delivery nano-platform for synergistic anti-tumor treatments. In this study, we have developed an mRNA-responsive two-in-one nano-drug for effective anti-tumor therapy by the direct self-assembly of 2'-fluoro-substituted antisense DNA against P-glycoprotein (2'F-DNA) and chemo drug paclitaxel (PTX). The 2'-fluoro modification of DNA could significantly increase the interaction between the therapeutic nucleic acid and the chemotherapeutic drug, promoting the successful formation of 2'F-DNA/PTX nanospheres (2'F-DNA/PTX NSs). Due to the one-step self-assembly process without additional carrier materials, the prepared 2'F-DNA/PTX NSs exhibited considerable loading efficiency and bioavailability of PTX. In the presence of endogenous P-glycoprotein mRNA, the 2'F-DNA/PTX NSs were disassembled. The released 2'F-DNA could down-regulate the expression of P-glycoprotein, which decreased the multidrug resistance of tumor cells and enhanced the chemotherapy effect caused by PTX. In this way, the 2'F-DNA/PTX NSs could synergistically induce the apoptosis of tumor cells and realize the combined anti-tumor therapy. This strategy might provide a new tool to explore functional intracellular co-delivery nano-systems with high bioavailability and exhibit potential promising in the applications of accurate diagnosis and treatment of tumors.

Polyvalent Aptamer-Functionalized NIR-II Quantum Dots for Targeted Theranostics in High PD-L1-Expressing Tumors

Ag2S quantum dots (QDs) show superior optical properties in the NIR-II region and display significant clinical potential with favorable biocompatibility. However, inherent defects of low targeting and poor solubility necessitate practical modification methods to achieve the theranostics of Ag2S QDs. Herein, we used rolling circle amplification (RCA) techniques to obtain long single-stranded DNA containing the PD-L1 aptamer and C-rich DNA palindromic sequence. The C-rich DNA palindromic sequences can specifically chelate Ag2+ and thus serve as a template to result in biomimetic mineralization and formation of pApt-Ag2S QDs. These QDs enable specific targeting and illuminate hot tumors with high PD-L1 expression effectively, serving as excellent molecular targeted probes. In addition, due to the high NIR-II absorption of Ag2S QDs, pApt-Ag2S QDs exhibit remarkable photothermal properties. And besides, polyvalent PD-L1 aptamers can recognize PD-L1 protein and effectively block the inhibitory signal of PD-L1 on T cells, enabling efficient theranostics through the synergistic effect of photothermal therapy and immune checkpoint blocking therapy. Summary, we enhance the biological stability and antibleaching ability of Ag2S QDs using long single-stranded DNA as a template, thereby establishing a theranostic platform that specifically targets PD-L1 high-expressing inflamed tumors and demonstrates excellent performance both in vitro and in vivo.

Recent Progress in Peptide-Based Molecular Probes for Disease Bioimaging

Recent strides in molecular pathology have unveiled distinctive alterations at the molecular level throughout the onset and progression of diseases. Enhancing the in vivo visualization of these biomarkers is crucial for advancing disease classification, staging, and treatment strategies. Peptide-based molecular probes (PMPs) have emerged as versatile tools due to their exceptional ability to discern these molecular changes with unparalleled specificity and precision. In this Perspective, we first summarize the methodologies for crafting innovative functional peptides, emphasizing recent advancements in both peptide library technologies and computer-assisted peptide design approaches. Furthermore, we offer an overview of the latest advances in PMPs within the realm of biological imaging, showcasing their varied applications in diagnostic and therapeutic modalities. We also briefly address current challenges and potential future directions in this dynamic field.

Stimuli-triggered Self-Assembly of Gold Nanoparticles: Recent Advances in Fabrication and Biomedical Applications

Gold nanoparticles have been widely used in engineering, material chemistry, and biomedical applications owing to their ease of synthesis and functionalization, localized surface plasmon resonance (LSPR), great chemical stability, excellent biocompatibility, tunable optical and electronic property. In recent years, the decoration and modification of gold nanoparticles with small molecules, ligands, surfactants, peptides, DNA/RNA, and proteins have been systematically studied. In this review, we summarize the recent approaches on stimuli-triggered self-assembly of gold nanoparticles and introduce the breakthrough of gold nanoparticles in disease diagnosis and treatment. Finally, we discuss the current challenge and future prospective of stimuli-responsive gold nanoparticles for biomedical applications.

Bioorthogonal "Click and Release" Reaction-Triggered Aggregation of Gold Nanoparticles Combined with Released Lonidamine for Enhanced Cancer Photothermal Therapy

Cancer has been the most deadly disease, and 13 million cancer casualties are estimated to occur each year by 2030. Gold nanoparticles (AuNPs)-based photothermal therapy (PTT) has attracted great interest due to its high spatiotemporal controllability and noninvasiveness. Due to the trade-off between particle size and photothermal efficiency of AuNPs, rational design is needed to realize aggregation of AuNPs into larger particles with desirable NIR adsorption in tumor site. Exploiting the bioorthogonal "Click and Release" (BCR) reaction between iminosydnone and cycloalkyne, aggregation of AuNPs can be achieved and attractively accompanied by the release of chemotherapeutic drug purposed to photothermal synergizing. We synthesize iminosydnone-lonidamine (ImLND) as a prodrug and choose dibenzocyclooctyne (DBCO) as the trigger of BCR reaction. A PEGylated AuNPs-based two-component nanoplatform consisting of prodrug-loaded AuNPs-ImLND and tumor-targeting peptide RGD-conjugated AuNPs-DBCO-RGD is designed. In the therapeutic regimen, AuNPs-DBCO-RGD are intravenously injected first for tumor-specific enrichment and retention. Once the arrival of AuNPs-ImLND injected later at tumor site, highly photothermally active nanoaggregates of AuNPs are formed via the BCR reaction between ImLND and DBCO. The simultaneous release of lonidamine further enhanced the therapeutic performance by sensitizing cancer cells to PTT.

Nanomaterials for light-mediated therapeutics in deep tissue

Light-mediated therapeutics, including photodynamic therapy, photothermal therapy and light-triggered drug delivery, have been widely studied due to their high specificity and effective therapy. However, conventional light-mediated therapies usually depend on the activation of light-sensitive molecules with UV or visible light, which have poor penetration in biological tissues. Over the past decade, efforts have been made to engineer nanosystems that can generate luminescence through excitation with near-infrared (NIR) light, ultrasound or X-ray. Certain nanosystems can even carry out light-mediated therapy through chemiluminescence, eliminating the need for external activation. Compared to UV or visible light, these 4 excitation modes penetrate more deeply into biological tissues, triggering light-mediated therapy in deeper tissues. In this review, we systematically report the design and mechanisms of different luminescent nanosystems excited by the 4 excitation sources, methods to enhance the generated luminescence, and recent applications of such nanosystems in deep tissue light-mediated therapeutics.

β-Galactosidase-Activated and Red Light-Induced RNA Modification Strategy for Prolonged NIR Fluorescence/PET Bimodality Imaging

Improving the retention of small-molecule-based therapeutic agents in tumors is crucial to achieve precise diagnosis and effective therapy of cancer. Herein, we propose a β-galactosidase (β-Gal)-activated and red light-induced RNA modification (GALIRM) strategy for prolonged tumor imaging. A β-Gal-activatable near-infrared (NIR) fluorescence (FL) and positron emission tomography (PET) bimodal probe 68Ga-NOTA-FCG consists of a triaaza triacetic acid chelator NOTA for 68Ga-labeling, a β-Gal-activated photosensitizer CyGal, and a singlet oxygen (1O2)-susceptible furan group for RNA modification. Studies have demonstrated that the probe emits an activated NIR FL signal upon cleavage by endogenous β-Gal overexpressed in the lysosomes, which is combined with the PET imaging signal of 68Ga allowing for highly sensitive imaging of ovarian cancer. Moreover, the capability of 68Ga-NOTA-FCG generating 1O2 under 690 nm illumination could be simultaneously unlocked, which can trigger the covalent cross-linking between furan and nucleotides of cytoplasmic RNAs. The formation of the probe-RNA conjugate can effectively prevent exocytosis and prolong retention of the probe in tumors. We thus believe that this GALIRM strategy may provide entirely new insights into long-term tumor imaging and efficient tumor treatment.

Self-propelled assembly of nanoparticles with self-catalytic regulation for tumour-specific imaging and therapy

Targeted assembly of nanoparticles in biological systems holds great promise for disease-specific imaging and therapy. However, the current manipulation of nanoparticle dynamics is primarily limited to organic pericyclic reactions, which necessitate the introduction of synthetic functional groups as bioorthogonal handles on the nanoparticles, leading to complex and laborious design processes. Here, we report the synthesis of tyrosine (Tyr)-modified peptides-capped iodine (I) doped CuS nanoparticles (CuS-I@P1 NPs) as self-catalytic building blocks that undergo self-propelled assembly inside tumour cells via Tyr-Tyr condensation reactions catalyzed by the nanoparticles themselves. Upon cellular internalization, the CuS-I@P1 NPs undergo furin-guided condensation reactions, leading to the formation of CuS-I nanoparticle assemblies through dityrosine bond. The tumour-specific furin-instructed intracellular assembly of CuS-I NPs exhibits activatable dual-modal imaging capability and enhanced photothermal effect, enabling highly efficient imaging and therapy of tumours. The robust nanoparticle self-catalysis-regulated in situ assembly, facilitated by natural handles, offers the advantages of convenient fabrication, high reaction specificity, and biocompatibility, representing a generalizable strategy for target-specific activatable biomedical imaging and therapy.

Recent Advances in Metallic Nanostructures-assisted Biosensors for Medical Diagnosis and Therapy

The field of nanotechnology has witnessed remarkable progress in recent years, particularly in its application to medical diagnosis and therapy. Metallic nanostructures-assisted biosensors have emerged as a powerful and versatile platform, offering unprecedented opportunities for sensitive, specific, and minimally invasive diagnostic techniques, as well as innovative therapeutic interventions. These biosensors exploit the molecular interactions occurring between biomolecules, such as antibodies, enzymes, aptamers, or nucleic acids, and metallic surfaces to induce observable alterations in multiple physical attributes, encompassing electrical, optical, colorimetric, and electrochemical signals. These interactions yield measurable data concerning the existence and concentration of particular biomolecules. The inherent characteristics of metal nanostructures, such as conductivity, plasmon resonance, and catalytic activity, serve to amplify both sensitivity and specificity in these biosensors. This review provides an in-depth exploration of the latest advancements in metallic nanostructures-assisted biosensors, highlighting their transformative impact on medical science and envisioning their potential in shaping the future of personalized healthcare.

Hafnium (Hf)-Chelating Porphyrin-Decorated Gold Nanosensitizers for Enhanced Radio-Radiodynamic Therapy of Colon Carcinoma

X-ray-induced radiodynamic therapy (RDT) that can significantly reduce radiation dose with an improved anticancer effect has emerged as an attractive and promising therapeutic modality for tumors. However, it is highly significant to develop safe and efficient radiosensitizing agents for tumor radiation therapy. Herein, we present a smart nanotheranostic system FA-Au-CH that consists of gold nanoradiosensitizers, photosensitizer chlorin e6 (Ce6), and folic acid (FA) as a folate-receptor-targeting ligand for improved tumor specificity. FA-Au-CH nanoparticles have been demonstrated to be able to simultaneously serve as radiosensitizers and RDT agents for enhanced computed tomography (CT) imaging-guided radiotherapy (RT) of colon carcinoma, owing to the strong X-ray attenuation capability of high-Z elements Au and Hf, as well as the characteristics of Hf that can transfer radiation energy to Ce6 to generate ROS from Ce6 under X-ray irradiation. The integration of RT and RDT in this study demonstrates great efficacy and offers a promising therapeutic modality for the treatment of malignant tumors.

Prolonging Treatment Window of Photodynamic Therapy with Self-Amplified H2 O2 -Activated Photodynamic/Chemo Combination Therapeutic Nanomedicines

Photodynamic therapy (PDT) is a promising approach to cancer therapy. However, the relatively short tumor retention time of photosensitizers (PSs) makes it difficult to catch the optimal treatment time and restricts multiple PDT within a single injection. In this study, a tumor-specific phototheranostic nanomedicine (DPPa NP) is developed for photodynamic/chemo combination therapy with a prolonged PDT treatment window. DPPa NP is prepared via encapsulating a hydrophobic oxidized bovine serum albumin (BSA-SOH)-conjugatable PS DPPa with amphiphilic H2 O2 -activatable chlorambucil (CL) prodrug mPEG-TK-CL. The released CL under H2 O2 treatment can not only kill tumor cells but also upregulate reactive oxygen species levels within tumor cells, leading to the almost full release of cargoes. The released DPPa may conjugate with overexpressed BSA-SOH, which results in the recovery of the fluorescence signal and photodynamic effect. More importantly, such conjugation transfers DPPa from a small molecule PS into a macromolecular PS with a long tumor retention time and treatment window of PDT, which enables multiple PDT. This study thus provides an effective strategy to prolong the treatment window of PDT and enables tumor-specific fluorescence imaging-guided combination therapy.

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.

Escherichia coli-Based In Situ Triggerable Probe as an Amplifier for Sensitive Diagnosis and Penetrated Therapy of Cancer

Escherichia coli (E. coli) was used for cancer therapy due to the tumor-targeting, catalytic, and surface-reducing properties. Effective diagnosis combined with treatment of cancer based on E. coli, however, was rarely demonstrated. In this study, E. coli was used to surface reduce HAuCl4 and as a carrier to modify riboflavin (Rf) and luminol (E-Au@Rf@Lum). After targeted delivery to tumor, the E-Au@Rf@Lum probe could actively emit 425 nm blue-violet chemiluminescence (CL) to achieve cell imaging for cancer diagnosis. Furthermore, this light could in situ trigger the photosensitizer (Rf) through CL resonance energy transfer, which produces reactive oxygen species (ROS) for accurate photodynamic therapy. In return, the excessive ROS enhanced the blue-violet light which was further absorbed by Rf, and ROS production was cyclically amplified. Abundant ROS broke down the dense extracellular matrix network and penetrated deep into tumors. Besides, E. coli with excellent catalytic property could decompose H2O2 to O2 to relieve tumor hypoxia for a long time and enhance the photosensitized process of Rf. By self-illumination, effective penetration, and tumor hypoxia relief, this work opens a self-amplified therapy modality to tumor.

Intelligent gold nanoparticles for malignant tumor treatment via spontaneous copper manipulation and on-demand photothermal therapy based on copper induced click chemistry

The excessive copper in tumor cells is crucial for the growth and metastasis of malignant tumor. Herein, we fabricated a nanohybrid to capture, convert and utilize the overexpressed copper in tumor cells, which was expected to achieve copper dependent photothermal damage of primary tumor and copper-deficiency induced metastasis inhibition, generating accurate and effective tumor treatment. The nanohybrid consistsed of 3-azidopropylamine, 4-ethynylaniline and N-aminoethyl-N'-benzoylthiourea (BTU) co-modified gold nanoparticles (AuNPs). During therapy, the BTU segment would specifically chelate with copper in tumor cells after endocytosis to reduce the intracellular copper content, causing copper-deficiency to inhibit the vascularization and tumor migration. Meanwhile, the copper was also rapidly converted to be cuprous by BTU, which further catalyzed the click reaction between azido and alkynyl on the surface of AuNPs, resulting in on-demand aggregation of these AuNPs. This process not only in situ generated the photothermal agent in tumor cells to achieve accurate therapy avoiding unexpected damage, but also enhanced its retention time for sustained photothermal therapy. Both in vitro and in vivo results exhibited the strong tumor inhibition and high survival rate of tumor-bearing mice after application of our nanohybrid, indicating that this synergistic therapy could offer a promising approach for malignant tumor treatment. STATEMENT OF SIGNIFICANCE: The distinctive excessive copper in tumor cells is crucial for the growth and metastasis of tumor. Therefore, we fabricated intelligent gold nanoparticles to simultaneously response and reverse this tumorigenic physiological microenvironment for the synergistic therapy of malignant tumor. In this study, for the first time we converted and utilized the overexpressed Cu2+ in tumor cells to trigger intracellular click chemistry for tumor-specific photothermal therapy, resulting in accurate damage of primary tumor. Moreover, we effectively manipulated the content of Cu2+ in tumor cells to suppress the migration and vascularization of malignant tumor, resulting in effective metastasis inhibition.

Multifunctional nano-system for multi-mode targeted imaging and enhanced photothermal therapy of metastatic prostate cancer

Prostate cancer (PCa) routinely employs magnetic resonance (MR) imaging, while metastatic PCa needs more complicated detection methods for precise localization. The inconvenience of using different methods to detect PCa and its metastases in patients and the limitations of single-mode imaging have brought great challenges to clinicians. Meanwhile, clinical treatments for metastatic PCa are still limited. Herein, we report a targeted theranostic platform of Au/Mn nanodots-luteinising hormone releasing hormone (AMNDs-LHRH) nano-system for multi-mode imaging guided photothermal therapy of PCa. The nano-system not only can simultaneously target Gonadotropin-Releasing Hormone Receptor (GnRH-R) positive PCa and its metastases for accurate preoperative CT/MR diagnosis, but also possesses fluorescence (FL) visualization navigated surgery, demonstrating its potential application in clinical cancer detection and surgery guidance. Meanwhile, the AMNDs-LHRH with promising targeting and photothermal conversion ability significantly improve the photothermal therapy effect of metastatic PCa. The AMNDs-LHRH nano-system guarantees the diagnostic accuracy and enhanced therapeutic effect, which provides a promising platform for clinical diagnosis and treatment of metastatic PCa. STATEMENT OF SIGNIFICANCE: Accurate clinical diagnosis and treatment of prostate cancer and its metastases is challenging. A targeted theranostic platform of AMNDs-LHRH nano-system for multi-mode imaging (FL/CT/MR) guided photothermal therapy of metastatic prostate cancer has been reported. The nano-system not only can simultaneously target prostate cancer and its metastases for accurate preoperative CT/MR diagnosis, but also possesses fluorescence visualization navigated surgery, demonstrating its potential application in clinical cancer detection and surgery guidance. The nano-system with great targeting and photothermal conversion ability significantly improve the photothermal therapy effect of metastatic prostate cancer. Overall, the AMNDs-LHRH nano-system integrates tumor targeting, multi-mode imaging and enhanced therapeutic effect, which can provide an effective strategy for the clinical diagnosis and treatment of metastatic PCa.

Light-initiated aggregation of gold nanoparticles for synergistic chemo-photothermal tumor therapy

The combination of chemotherapy with photothermal therapy (PTT) has attracted extensive attention due to its excellent synergetic effect attributing to the fact that hyperthermia can effectively promote the tumor uptake of chemotherapeutic drugs. Herein, we propose a light-initiated gold nanoparticle (AuNP) aggregation boosting the uptake of chemotherapeutic drugs for enhanced chemo-photothermal tumor therapy. Novel light-responsive AuNPs (tm-AuNPs) were rationally designed and fabricated by conjugating both 2,5-diphenyltetrazole (Tz) and methacrylic acid (Ma) onto the surface of AuNPs with small size (∼20 nm). Upon the irradiation of 405 nm laser, AuNPs could be initiated to form aggregates specifically within tumors through the covalent cycloaddition reaction between Tz and Ma. Taking advantage of the controllable photothermal effect of Au aggregates under NIR excitation, improved enrichment of doxorubicin (DOX) in tumor tissues was realized, combined with PTT, resulting in outstanding synergetic anti-tumor efficacy in living mice. We thus believe that this light-initiated AuNP aggregation approach would offer a valuable and powerful tool for precisely synergistic chemo-photothermal tumor therapy.

Activatable dual-functional molecular agents for imaging-guided cancer therapy

Theranostics has attracted great attention due to its ability to combine the real-time diagnosis of cancers with efficient treatment modalities. Activatable dual-functional molecular agents could be synthesized by covalently conjugating imaging agents, therapeutic agents, stimuli-responsive linkers and/or targeting molecules together. They could be selectively activated by overexpressed physiological stimuli or external triggers at the tumor sites to release imaging agents and cytotoxic drugs, thus offering many advantages for tumor imaging and therapy, such as a high signal-to-noise ratio, low systemic toxicity, and improved therapeutic effects. This review summarizes the recent advances of dual-functional molecular agents that respond to various physiological or external stimuli for cancer theranostics. The molecular designs, synthetic strategies, activatable mechanisms, and biomedical applications of these molecular agents are elaborated, followed by a brief discussion of the challenges and opportunities in this field.

Peroxidase-Mimicking Hierarchically Organized Gold Particles for Glucose Detection

In this work, we synthesize a series of hierarchically organized gold nanoparticles (Au HOPs-X) with peroxidase (POD)-like catalytic activity by the in situ reduction of Au-thiolate hierarchically organized particles (Au HOPs). The initial Au HOPs show little POD-like catalytic activity. However, after the reduction of the particles, the Au HOPs-X showed enhanced POD-like catalytic activity, where X represents the reduction degree of Au HOPs. The reasons are as follows: (1) the Au-thiolate complexes on the surface of the Au HOPs-X were reduced into Au nanoparticles, and the active Au⁰ content increases with the increase of the reduction degree; (2) the specific surface area of Au HOPs-X becomes larger. Based on this, the Au HOPs-10 with the highest catalytic activity were combined with glucose oxidase to obtain a standard curve as a function of glucose concentrations. The color of the solutions was captured by mobile phone photos to determine their saturation, and the rapid detection of glucose was achieved through the standard curve of glucose concentration and saturation determined in this study.

A tumor-targetable NIR probe with photoaffinity crosslinking characteristics for enhanced imaging-guided cancer phototherapy

Spatiotemporally manipulating the in situ immobilization of theranostic agents within cancer cells to improve their bioavailability is highly significant yet challenging in tumor diagnosis and treatment. Herein, as a proof-of concept, we for the first time report a tumor-targetable near-infrared (NIR) probe DACF with photoaffinity crosslinking characteristics for enhanced tumor imaging and therapeutic applications. This probe possesses great tumor-targeting capability, intensive NIR/photoacoustic (PA) signals, and a predominant photothermal effect, allowing for sensitive imaging and effective photothermal therapy (PTT) of tumors. Most notably, upon 405 nm laser illumination, DACF could be covalently immobilized within tumor cells through a photocrosslinking reaction between photolabile diazirine groups and surrounding biomolecules resulting in enhanced tumor accumulation and prolonged retention simultaneously, which significantly facilitates the imaging and PTT efficacy of tumor in vivo. We therefore believe that our current approach would provide a new insight for achieving precise cancer theranostics.

Fluorescence, ultrasonic and photoacoustic imaging for analysis and diagnosis of diseases

Biomedical imaging technology, which allows us to peer deeply within living subjects and visually explore the delivery and distribution of agents in living things, is producing tremendous opportunities for the early diagnosis and precise therapy of diseases. In this feature article, based on reviewing the latest representative examples of progress together with our recent efforts in the bioimaging field, we intend to introduce three typical kinds of non-invasive imaging technologies, i.e., fluorescence, ultrasonic and photoacoustic imaging, in which optical and/or acoustic signals are employed for analyzing various diseases. In particular, fluorescence imaging possesses a series of outstanding advantages, such as high temporal resolution, as well as rapid and sensitive feedback. Hence, in the first section, we will introduce the latest studies on developing novel fluorescence imaging methods for imaging bacterial infections, cancer and lymph node metastasis in a long-term and real-time manner. However, the issues of imaging penetration depth induced by photon scattering and light attenuation of biological tissue limit their widespread in vivo imaging applications. Taking advantage of the excellect penetration depth of acoustic signals, ultrasonic imaging has been widely applied for determining the location, size and shape of organs, identifying normal and abnormal tissues, as well as confirming the edges of lesions in hospitals. Thus, in the second section, we will briefly summarize recent advances in ultrasonic imaging techniques for diagnosing diseases in deep tissues. Nevertheless, the absence of lesion targeting and dependency on a professional technician may lead to the possibility of false-positive diagnosis. By combining the merits of both optical and acoustic signals, newly-developed photoacoustic imaging, simultaneously featuring higher temporal and spatial resolution with good sensitivity, as well as deeper penetration depth, is discussed in the third secretion. In the final part, we further discuss the major challenges and prospects for developing imaging technology for accurate disease diagnosis. We believe that these non-invasive imaging technologies will introduce a new perspective for the precise diagnosis of various diseases in the future.

Novel strategies for tumor radiosensitization mediated by multifunctional gold-based nanomaterials

Radiotherapy (RT) is one of the most effective and commonly used cancer treatments for malignant tumors. However, the existing radiosensitizers have a lot of side effects and poor efficacy, which limits the curative effect and further application of radiotherapy. In recent years, emerging nanomaterials have shown unique advantages in enhancing radiosensitization. In particular, gold-based nanomaterials, with high X-ray attenuation capacity, good biocompatibility, and promising chemical, electronic and optical properties, have become a new type of radiotherapy sensitizer. In addition, gold-based nanomaterials can be used as a carrier to load a variety of drugs and immunosuppressants; in particular, its photothermal therapy, photodynamic therapy and multi-mode imaging functions aid in providing excellent therapeutic effect in coordination with RT. Recently, many novel strategies of radiosensitization mediated by multifunctional gold-based nanomaterials have been reported, which provides a new idea for improving the efficacy and reducing the side effects of RT. In this review, we systematically summarize the recent progress of various new gold-based nanomaterials that mediate radiosensitization and describe the mechanism. We further discuss the challenges and prospects in the field. It is hoped that this review will help researchers understand the latest progress of gold-based nanomaterials for radiosensitization, and encourage people to optimize the existing methods or explore novel approaches for radiotherapy.

Biomimetic macrophage membrane-coated gold-quantum dots with tumor microenvironment stimuli-responsive capability for tumor theranostic

Tumor microenvironment (TME) is intently related to tumor growth, progression and invasion, leading to drug resistance and insufficient therapeutic efficacy. However, remodeling TME and utilizing TME for exploring intelligent nanomaterials that can realize tumor theranostic is still challenging. Nowadays, the theranostic based on chemotherapy exposes some deficiencies, such as low targeting, weak permeability and premature clearance. Furthermore, it is challenging to cure drug-resistant tumors effectively. For the sake of solving these problems, a biomimetic decomposable nano-theranostic (MMV-Au-CDs-DOX) was well-established in this work. The Au-CDs are coated with macrophage-derived microvesicle to realize drug release accurately and enhance the biocompatibility of internal nanoparticles. Furthermore, MMV-Au-CDs-DOX would locate in the inflammation position of tumor, and disintegrate correspondingly into pieces with certain different functions stimulated by TME. Subsequently, the released anti-tumor nanodrugs were used for multimodal therapy, including chemotherapy and hemodynamic therapy. In addition, combined with the ability of Au-CDs to recognize GSH specifically, the off-on fluorescent probe was constructed to monitor the GSH of tumor cells and provided information on chemotherapy resistance.

Cascade Catalytically Released Nitric Oxide-Driven Nanomotor with Enhanced Penetration for Antibiofilm

Nanodrugs are becoming increasingly important in the treatment of bacterial infection, but their low penetration ability to bacterial biofilm is still the main challenge hindering their therapeutic effect. Herein, nitric oxide (NO)-driven nanomotor based on L-arginine (L-Arg) and gold nanoparticles (AuNPs) loaded dendritic mesoporous silica nanoparticles (AG-DMSNs) is fabricated. AG-DMSNs have the characteristics of cascade catalytic reaction, where glucose is first catalyzed by the asymmetrically distributed AuNPs with their glucose oxidase (GOx)- mimic property, which results in unilateral production of hydrogen peroxide (H₂ O₂ ). Then, L-Arg is oxidized by the produced H₂ O₂ to release NO, leading to the self-propelled movement. It is found that the active movement of nanomotor promotes the AG-DMSNs ability to penetrate biofilm, thus achieving good biofilm clearance in vitro. More importantly, AG-DMSNs nanomotor can eliminate the biofilm of methicillin-resistant Staphylococcus aureus (MRSA) in vivo without causing damage to normal tissues. This nanomotor provides a new platform for the treatment of bacterial infections.

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.

DNA Tetrahedron Framework Guided Conjugation and Assembly of Gold Nanoparticles

Au nanoparticles (AuNPs) have been extensively used to assemble programmable structures that feature various functions. One central challenge of precisely directed assembly is to make valence-programmable building blocks. Herein, we use the DNA tetrahedron framework to stoichiometrically conjugate to Au nanoparticles, which results in monovalent building blocks at nanometer scale. We further fabricated high-order Au-tetrahedron structures to verify the ability of the blocks for building assemblies. These structures represent an exploration of an avenue to monovalent AuNPs, and provide the feasibility of precisely manipulating nanoparticles into prescribed assemblies.

Oxygen Vacancy-Dependent Chemiluminescence: A Facile Approach for Quantifying Oxygen Defects in ZnO

Defect engineering is an effective strategy to improve the catalytic activity of metal oxides, and quantitative characterization of surface defects is thus vital to the understanding and application of metal oxide catalysts. Herein, we found that ZnO nanoparticles with oxygen vacancy could trigger the luminol-H₂O₂ system to emit a strong chemiluminescence (CL), and the CL intensity was strongly dependent on the oxygen vacancy of the ZnO nanoparticles. The mechanism of this CL reaction was discussed by means of the electron-spin resonance spectrum, X-ray photoelectron spectrum (XPS), and CL spectrum. The oxygen vacancy-dependent CL was attributed to the ability of the oxygen vacancy to readily adsorb and further dissociate H₂O₂ into active ^•OH radicals. Taking advantage of this oxygen vacancy-dependent CL, we presented one method for quantifying the oxygen defects in ZnO. Compared with the current evaluation techniques (XPS and Raman spectroscopy), this CL method is rapid, low-cost, and easy to operate. This work introduces the CL technique into the field of material structure-property evaluation, and provides a new approach for exploring the defect function in ZnO defect engineering.

Intracellular miRNA-Triggered Surface-Enhanced Raman Scattering Imaging and Dual Gene-Silencing Therapy of Cancer Cell

Development of theranostic nanosystems integrating cascaded surface-enhanced Raman scattering (SERS) imaging and gene silencing therapy for accurate cancer diagnosis and treatment is still a big challenge and rarely reported. Herein, a novel Au nanoparticles (AuNPs)-based theranostic nanosystem containing AuNP-Ys and AuNP-Ds for highly sensitive and specific cancer diagnosis and treatment was proposed for cascaded SERS imaging of intracellular cancer-related miR-106a and miR-106a-triggered DNAzyme-based dual gene-silencing therapy of cancer cells. The AuNP-Ys were prepared by modifying the AuNPs with specially designed Y-motifs, and the AuNP-Ds were obtained by colabeling Raman molecules and dsDNA linkers on AuNPs. When identifying the intracellular cancer-related miRNAs, the Y-motifs and dsDNA linkers undergoes miRNA-triggered ATP-driven conformational transitions and releases the miRNA for recycling, which results in the formation of AuNP network nanostructures to generate significantly enhanced SERS signals for sensitive identification of the cancer cells as well as the amplification and specific activation of DNAzymes to catalyze the Mg²⁺-assisted cleavage of the Survivin and c-Jun mRNAs for effective dual gene-silencing therapy of cancer cells. The AuNP-based theranostic nanosystem achieves the synergism of target-triggered SERS imaging and DNAzyme-based dual gene-silencing therapy with enhanced specificity, sensitivity, and curative effect, which can be a powerful tool for accurate diagnosis and efficient treatment of cancers.

AuNCs-LHRHa nano-system for FL/CT dual-mode imaging and photothermal therapy of targeted prostate cancer

As the most common cancer in men worldwide, prostate cancer has a serious impact on people's health. Until now, the development of a platform for integrating tumor targeting, imaging and an effective treatment for prostate cancer has remained challenging. Herein, a nano-system is designed to improve both diagnosis and treatment for prostate cancer. We successfully synthesized an AuNCs-LHRHa nano-system by combining PEI-modified gold nanoclusters (AuNCs) with LHRH analogues (LHRHa). Due to the good tunable optical properties and photothermal properties of AuNCs, the nano-system can not only achieve efficient fluorescence/computed tomography dual-mode imaging, but can also be used for photothermal therapy (PTT). After modifying the LHRHa antibody of a prostate tumor, AuNCs-LHRHa can be more effectively recognized by the gonadotropin-releasing hormone receptors (GnRH-R) on the membrane of RM-1 cells, enhancing the tumor cell uptake of the nano-system, improving the targeting accuracy and PTT therapy efficacy for prostate cancer. It is hoped that the nano-system, which combines dual-mode imaging and targeted therapy, will provide a promising strategy for the integration of FL/CT diagnosis and PTT therapy for GnRH-R positive prostate cancer.

Rigid metal/liquid metal nanoparticles: Synthesis and application for locally ablative therapy

Locally ablative therapy, as the main therapy for advanced tumors, has fallen into a bottleneck in recent years. The breakthrough of metal nanoparticles provides a novel approach for ablative therapy. Previous studies have mostly focused on the combined field of rigid metal nanoparticles and ablation. However, with the maturity of the preparation process of liquid metal nanoparticles, liquid metal nanoparticles not only have metallic properties but also have fluid properties, showing the potential to be combined with ablation. At present, there is no review on the combination of liquid metal nanoparticles and ablation. In this article, we first review the preparation, characterization and application characteristics of rigid metal and liquid metal nanoparticles in ablation applications, and then summarize the advantages, disadvantages and possible future development trends of rigid and liquid metal nanoparticles.

Polymeric agents for activatable fluorescence, self-luminescence and photoacoustic imaging

Numerous polymeric agents have been widely applied in biology and medicine by virtue of the facile chemical modification, feasible nano-engineering approaches and fine-tuned pharmacokinetics. To endow polymeric imaging agents with ability to monitor and measure subtle molecular or cellular alterations at diseased sites, activatable polymeric probes that can elicit signal changes in response to biomolecular interactions or the analytes of interest have to be developed. Herein, this review aims to provide a systemic interpretation and summarization of the design methodology and imaging utility of recently emerged activatable polymeric probes. An introduction of activatable probes allowing for precise imaging and classification of polymeric imaging agents is reported first. Then, we give a detailed discussion of the contemporary design approaches toward activatable polymeric probes in diverse imaging modes for the detection of various stimuli and their imaging applications. Finally, current challenges and future advances are discussed and highlighted.

When imaging meets size-transformable nanosystems

Imaging techniques, including magnetic, optical, acoustic and nuclear imaging, are gaining popularity as a research tool and clinical diagnostics. The advent of imaging agents-incorporated nanosystems (NSs), with sufficient contrast and high resolution, facilitates better monitoring of disease progression, targeted delivery and therapeutic process. Of note, the size of NSs remarkably affects imaging performance, while both large and small NSs enjoy respective features and superiority for imaging aspect, including penetration depth, signal-to-background ratio and spatiotemporal resolution. In this review, after a systematic summary of the basic knowledge of imaging techniques and its relation with size-tunable strategies, we further provide insights into the opportunities and challenges facing size-transformable NSs of the future for bio-imaging application and clinical translation.