Gold Nanoframeworks with Mesopores for Raman-Photoacoustic Imaging and Photo-Chemo Tumor Therapy in the Second Near-Infrared Biowindow

Gold Nano Frameworks with Mesopores for Synergistic Immune-Thermal Therapy in Hepatic Carcinoma: A Paradigm Shift in Immune Checkpoint Blockade

Immune checkpoint blockade (ICB) therapy, while showing promise in various cancers, exhibits limited effectiveness in hepatic carcinoma due to the tumor's immunosuppressive microenvironment (TME) and challenges associated with immune cell infiltration. Efforts to transform the "cold" TME into an "inflamed" state, notably through chemo-immunotherapy, have sparked interest due to their potential to induce immunogenic cell death and augment the infiltration of cytotoxic T lymphocytes (CTLs). Nonetheless, the efficacy of chemo-immunotherapy is often compromised by suboptimal pharmacokinetics, poor tumor accumulation, and off-target toxicity. Herein, in response, we introduce an innovative, milder thermal therapeutic approach leveraging gold nano frameworks with mesopores for the targeted delivery of the immunostimulant imiquimod and NIR-II photothermal therapy. This strategy employs targeted molecule modifications to ensure precise tumor targeting, guided by photoacoustic imaging. Subsequent to mild thermal treatment, there is a release of immunogenic proteins (CRT and HSP90), enhancing tumor immunogenicity. Assisted by imiquimod, substantial CTL infiltration occurs, accompanied by pro-inflammatory factor release (TNF-α, IL-6), transforming M2 macrophages into the M1 phenotype. Ultimately, the proposed strategy combines PD-L1/PD-1 blockade, imiquimod and mild thermal treatment to synergistically enhance tumor immunogenicity, remodel the TME, and restrain hepatic carcinoma, making strides in ICB synergistic immune-thermal therapy.

Hypoxia Reversion and STING Pathway Activation through Large Mesoporous Nanozyme for Near-Infrared-II Light Amplified Tumor Polymetallic-Immunotherapy

cGAS/STING pathway, which is highly related to tumor hypoxia, is considered as a potential target for remodeling the immunosuppressive microenvironment of solid tumors. Metal ions, such as Mn2+, activate the cGAS/STING pathway, but their efficacy in cancer therapy is limited by insufficient effect on immunogenic tumor cell death of a single ion. Here, we evaluate the association between tumor hypoxia and cGAS/STING inhibition and report a polymetallic-immunotherapy strategy based on large mesoporous trimetal-based nanozyme (AuPdRh) coordinated with Mn2+ (Mn2+@AuPdRh) to activate cGAS/STING signaling for robust adaptive antitumor immunity. Specifically, the inherent CAT-like activity of this polymetallic Mn2+@AuPdRh nanozyme decomposes the endogenous H2O2 into O2 to relieve tumor hypoxia induced suppression of cGAS/STING signaling. Moreover, the Mn2+@AuPdRh nanozyme displays a potent near-infrared-II photothermal effect and strong POD-mimic activity; and the generated hyperthermia and •OH radicals synergistically trigger immunogenic cell death in tumors, releasing abundant dsDNA, while the delivered Mn2+ augments the sensitivity of cGAS to dsDNA and activates the cGAS-STING pathway, thereby triggering downstream immunostimulatory signals to kill primary and distant metastatic tumors. Our study demonstrates the potential of metal-based nanozyme for STING-mediated tumor polymetallic-immunotherapy and may inspire the development of more effective strategies for cancer immunotherapy.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Efficient Photothermal Sensor Based on Coral-Like Hollow Gold Nanospheres for the Sensitive Detection of Sulfonamides

Gold nanoparticles (AuNPs), universally regarded as colorimetric signal reporters, are widely employed in lateral flow immunoassays (LFIAs). However, it is difficult for AuNPs-LFIA to achieve a wide range and sensitive detection. Herein, novel coral-like hollow gold nanospheres (CHGNPs) are synthesized. The growth of gold nanospheres can be regulated to obtain a multibranched and hollow construction. The obtained CHGNPs possess intense broadband absorption across the visible to near-infrared region, exhibiting a high molar extinction coefficient of 14.65 × 1011 M-1 cm-1 and a photothermal conversion efficiency of 79.75%. Thus, the photothermal/colorimetric dual-readout LFIA is developed based on CHGNPs (CHGNPs-PT-LFIA and CHGNPs-CM-LFIA) to effectively improve the detection sensitivity and broaden the detection range in regard to sulfonamides (SAs). The limits of detection of the CHGNPs-PT-LFIA and CHGNPs-CM-LFIA reached 1.9 and 2.8 pg mL-1 for the quantitative detection of sulfaquinoxaline, respectively, which are 6.3-fold and 4.3-fold lower than that of the AuNPs-LFIA. Meanwhile, the CHGNPs-PT-LFIA broadened the detection range to three orders of magnitude, which ranged from 2.5 to 5000 pg mL-1. The synthesized photothermal CHGNPs have been proven effective in improving the performance of the LFIA and provide a potential option for the construction of sensing platforms.

A Novel Multi-Effect Photosensitizer for Tumor Destruction via Multimodal Imaging Guided Synergistic Cancer Phototherapy

Background

How to ingeniously design multi-effect photosensitizers (PSs), including multimodal imaging and multi-channel therapy, is of great significance for highly spatiotemporal controllable precise phototherapy of malignant tumors.

Methods

Herein, a novel multifunctional zinc(II) phthalocyanine-based planar micromolecule amphiphile (ZnPc 1) was successfully designed and synthesized, in which N atom with photoinduced electron transfer effect was introduced to enhance the near-infrared absorbance and nonradiative heat generation. After simple self-assembling into nanoparticles (NPs), ZnPc 1 NPs would exhibit enhanced multimodal imaging properties including fluorescence (FL) imaging (FLI) /photoacoustic (PA) imaging (PAI) /infrared (IR) thermal imaging, which was further used to guide the combined photodynamic therapy (PDT) and photothermal therapy (PTT).

Results

It was that under the self-guidance of the multimodal imaging, ZnPc 1 NPs could precisely pinpoint the tumor from the vertical and horizontal boundaries achieving highly efficient and accurate treatment of cancer.

Conclusion

Accordingly, the integration of FL/PA/IR multimodal imaging and PDT/PTT synergistic therapy pathway into one ZnPc 1 could provide a blueprint for the next generation of phototherapy, which offered a new paradigm for the integration of diagnosis and treatment in tumor and a promising prospect for precise cancer therapy.

Inhomogeneous Au2S for Photoacoustic Imaging and Photodynamic Tumor Therapy Based on Different Forms of Energy Dissipation

Nanomaterials with unique structures and components play a crucial role in nanomedicine. In this study, we discovered that the inhomogeneous Au2S constructed by cation exchange and acid etching could dissipate energy in different forms after absorbing multichromatic light, which could be used to achieve the integrated diagnosis and treatment of tumors, respectively. Folic acid modified Au2S ringed nanoparticles (FA-Au2S RNs) with an assembly-like structure were demonstrated to result in better PA imaging performance and generate more reactive oxygen species (O2·-, ·OH, and 1O2) than folic acid modified Au2S triangular nanoparticles (FA-Au2S TNs). Finite element analyses determined the reason for the high absorbance properties and synergistic enhancement of plasma resonance in the assembly-like structure of Au2S RNs. Both FA-Au2S nanostructures were modified with folic acid and injected into 4T1 tumor-bearing mice via the tail vein. The best PA imaging contrast was obtained under 700 nm laser illumination, and the most effective PDT antitumor activity was achieved under 1064 nm laser illumination. The PA average of the tumor in the FA-Au2S RN group was approximately 2 times higher than that of the FA-Au2S TN group at 24 h of injection. The PA imaging results of intratumorally injected FA-Au2S RNs proved that they were still able to show better PA signal enhancement at 24 h postinjection. Our study demonstrates that FA-Au2S nanomaterials with unique structures and special properties can be reliably produced using strictly controlled chemical synthesis. It further provides a strategy for the construction of highly sensitive PA imaging platforms and efficient PDT antitumor agents that exploit wavelength-dependent energy dissipation mechanisms.

Piezocatalytic Schottky Junction Treats Atherosclerosis by a Biomimetic Trojan Horse Strategy

The atherosclerotic vulnerable plaque is characterized by the foamy macrophage burden, involving impaired cholesterol efflux and deficient efferocytosis. Correspondingly, piezocatalytic therapy is an emerging solution for eliminating the foamy macrophage burden with satisfactory spatiotemporal controllability and deep penetration depth. Herein, a biomimetic Trojan horse (Au-ZnO@MM) is engineered by coating the macrophage membrane (MM) onto the surface of a rod-like Au-ZnO Schottky Junction to effectively relieve the atherosclerotic progression. These Trojan horses with the coating of MM are actively transported into subsistent foamy macrophages and generate abundant reactive oxygen species (ROS) via ultrasound-activated piezocatalysis. ROS-initiated autophagy and mitochondrial dysfunction induce substantial cell apoptosis, alleviating the burden of subsistent foamy macrophages. The resulting apoptotic fragments further significantly facilitate cholesterol excretion and trigger efferocytosis of intraplaque fresh macrophages. Ultimately, the biomimetic Au-ZnO@MM piezocatalyst not only inhibits the foaming capacity of macrophages, but also improves the function of removing cell debris, which can stabilize atherosclerotic vulnerable plaque. Meanwhile, the plasmon resonance effect of integrated gold nanoparticles enables favorable photoacoustic molecular imaging for real-time image-guided atherosclerotic therapy. This proposed biomimetic Trojan horse strategy provides the paradigm of employing ultrasound-activated piezocatalytic methodology for enhanced atherosclerotic theranostics.

A bubble-enhanced lanthanide-doped up/down-conversion platform with tumor microenvironment response for dual-modal photoacoustic and near-infrared-II fluorescence imaging

As an important tumor diagnosis strategy in precision medicine, multimodal imaging has been widely studied. However, the weak imaging signal with low spatial resolution and the constant signal of lack of specific activation severely limit its disease diagnosis. Herein, a bubble-enhanced lanthanide-based up/down-conversion platform with tumor microenvironment response for dual-mode imaging, LDNP@DMSN-Au@CaCO3 nanoparticles (named as LDAC NPs) were successfully developed. Combining the advantages of photoacoustic imaging (PAI) and the second near-infrared window (NIR-II) fluorescence imaging (FI), significantly improved the accuracy of diseases diagnosis. LDAC NPs with flower-like structure were synthesized through the encapsulation of uniform lanthanide-doped nanoparticles (NaYbF4:Ce,Er@NaYF4 named LDNPs) with dendritic mesoporous silica (DMSN). The gold nanoparticles (Au NPs) were then in situ grown on the surface of DMSN and the surface were finally coated with a layer of calcium carbonate (CaCO3). Under the excitation of the 980 nm laser, LDNPs showed strong emission of NIR-II at 1550 nm due to the doping of Ce and Er ions, showcasing excellent spatial resolution and deep tissue penetration characteristics, while the resulting visible light emission (540 nm) enables Au NPs to generate PAI signals with the aid of LDNPs via the fluorescence resonance energy transfer effect. In acidic tumoral environment, CaCO3 layer could produce CO2 microbubbles, and the PAI signals of LDAC NPs could be further enhanced with the generation of CO2 bubbles due to the bubble cavitation effect. Simultaneously, the NIR-II FI of LDAC NPs was self-enhanced with the degradation of the CaCO3. This intelligent nanoparticle with stimulus-activated dual-mode imaging capability holds great promise in future precision diagnostics.

Pyroelectric-Effect-Assisted Near-Infrared-Driven Photoelectrochemical Biosensor Based on Exponential DNA Amplifier for MicroRNA Detection

Although near-infrared responsive photoelectrochemical (PEC) biosensors have less damage to biological components compared to UV-visible light, they still reveal an inferior response due to the rapid recombination of photogenerated electron-hole. In this study, a near-infrared-driven PEC biosensor is fabricated for microRNA (miRNA) detection via integrating photoelectricity and pyroelectricity. Upon the introduction of target miRNA-21, the exponential DNA amplifier is triggered based on enzyme-assisted strand displacement amplification (SDA), releasing multiple Ag2S reporter probes to hybridize with capture probes immobilized on a CdS-2-mercaptobenzimidazole (2MBI)-modified photoelectrode. As a result, under the stimulation of NIR, the photoelectric conversion of Ag2S NPs generates the photocurrents. In addition, due to the strong hole acceptor ability of MBI, the pyroelectric effect of CdS-2MBI nanocomposites is enhanced, which generates highly pyroelectro-induced charge separation efficiency and induces the pyroelectric current benefited from the spontaneous polarization of CdS-2MBI caused by the temperature variation under the function of Ag2S nanoheaters. Impressively, this PEC biosensor has achieved the sensitive and selective determination of miRNA-21 with a detection limit as low as 54 fM. Overall, this NIR-driven PEC biosensor based on pyroelectric and photoelectric effects opens up a new horizon for bioanalysis and early disease diagnosis.

Natural lipid nanoparticles extracted from Morus nigra L. leaves for targeted treatment of hepatocellular carcinoma via the oral route

The clinical application of conventional medications for hepatocellular carcinoma treatment has been severely restricted by their adverse effects and unsatisfactory therapeutic effectiveness. Inspired by the concept of 'medicine food homology', we extracted and purified natural exosome-like lipid nanoparticles (LNPs) from black mulberry (Morus nigra L.) leaves. The obtained MLNPs possessed a desirable hydrodynamic particle size (162.1 nm), a uniform size distribution (polydispersity index = 0.025), and a negative surface charge (-26.6 mv). These natural LNPs were rich in glycolipids, functional proteins, and active small molecules (e.g., rutin and quercetin 3-O-glucoside). In vitro experiments revealed that MLNPs were preferentially internalized by liver tumor cell lines via galactose receptor-mediated endocytosis, increased intracellular oxidative stress, and triggered mitochondrial damage, resulting in suppressing the viability, migration, and invasion of these cells. Importantly, in vivo investigations suggested that oral MLNPs entered into the circulatory system mainly through the jejunum and colon, and they exhibited negligible adverse effects and superior anti-liver tumor outcomes through direct tumor killing and intestinal microbiota modulation. These findings collectively demonstrate the potential of MLNPs as a natural, safe, and robust nanomedicine for oral treatment of hepatocellular carcinoma.

Photothermal-driven micro/nanomotors: From structural design to potential applications

Micro/nanomotors (MNMs) that accomplish autonomous movement by transforming external energy into mechanical work are attractive cargo delivery vehicles. Among various propulsion mechanisms of MNMs, photothermal propulsion has gained considerable attention because of their unique advantages, such as remote, flexible, accurate, biocompatible, short response time, etc. Moreover, besides as a propulsion source, the light has been extensively investigated as an excitation source in bioimaging, photothermal therapy (PTT), photodynamic therapy (PDT) and so on. Furthermore, the geometric topology and morphology of MNMs have a tremendous impact on improving their performance in motion behavior under NIR light propulsion, environmental suitability and functional versatility. Hence, this review article provides a comprehensive overview of structural design principles and construction strategies of photothermal-driven MNMs, and their emerging nanobiomedical applications. Finally, we further provide an outlook towards prospects and challenges during the development of photothermal-driven MNMs in the future. STATEMENT OF SIGNIFICANCE: Photothermal-driven micro/nanomotors (MNMs) that are regarded as functional cargo delivery tools have gained considerable attention because of unique advantages in propulsion mechanisms, such as remote, flexible, accurate and fully biocompatible light manipulation and extremely short light response time. The geometric topology and morphology of MNMs have a tremendous impact on improving their performance in motion behavior under NIR light propulsion, environmental suitability and functional versatility of MNMs. There are no reports about the review focusing on photothermal-driven MNMs up to now. Herein, we systematically review the latest progress of photothermal-driven MNMs including design principle, fabrication strategy of various MNMs with different structures and nanobiomedical applications. Moreover, the summary and outlook on the development prospects and challenges of photothermal-driven MNMs are proposed, hoping to provide new ideas for the future design of photothermal-driven MNMs with efficient propulsion, multiple functions and high biocompatibility.

Plasmonic porous micro- and nano-materials based on Au/Ag nanostructures developed for photothermal cancer therapy: challenges in clinicalization

Photothermal therapy (PTT) has developed in recent decades as a relatively safe method for the treatment of cancers. Recently, various species of gold and silver (Au and Ag) nanostructures have been developed and investigated to achieve PTT due to their highly localized surface plasmon resonance (LSPR) effect. Concisely, the collective oscillation of electrons on the surface of Au and Ag nanostructures upon exposure to a specific wavelength (depending on their size and shape) and further plasmonic resonance leads to the heating of the surface of these particles. Hence, porous species can be equipped with tiny plasmonic ingredients that add plasmonic properties to therapeutic cargoes. In this case, a precise review of the recent achievements is very important to figure out to what extent plasmonic photothermal therapy (PPTT) by Au/Ag-based plasmonic porous nanomedicines successfully treated cancers with satisfactory biosafety. Herein, we classify the various species of LSPR-active micro- and nano-materials. Moreover, the routes for the preparation of Ag/Au-plasmonic porous cargoes and related bench assessments are carefully reviewed. Finally, as the main aim of this study, principal requirements for the clinicalization of Ag/Au-plasmonic porous cargoes and their further challenges are discussed, which are critical for specialists in this field.

Surface-enhanced Raman scattering sensing for detection and mapping of key cellular biomarkers

Cellular biomarkers mainly contain proteins, nucleic acids, glycans and many small molecules including small biomolecule metabolites, reactive oxygen species and other cellular chemical entities. The detection and mapping of the key cellular biomarkers can effectively help us to understand important cellular mechanisms associated with physiological and pathological processes, which greatly promote the development of clinical diagnosis and disease treatment. Surface-enhanced Raman scattering (SERS) possesses high sensitivity and is free from the influence of strong self-fluorescence in living systems as well as the photobleaching of the dyes. It exhibits rich and narrow chemical fingerprint spectra for multiplexed detection, and has become a powerful tool to detect and map cellular biomarkers. In this review, we present an overview of recent advances in the detection and mapping of different classes of cellular biomarkers based on SERS sensing. These advances fully confirm that the SERS-based sensors and sensing methods have great potential for the exploration of biological mechanisms and clinical applications. Additionally, we also discuss the limitations of present research and the future developments of the SERS technology in this field.

Liposome-Templated Green Synthesis of Mesoporous Metal Nanostructures with Universal Composition for Biomedical Application

Porous noble metal nanoparticles have received particular attention recently for their unique optical, thermal, and catalytic functions in biomedicine. However, limited progress has been made to synthesize such porous metallic nanostructures with large mesopores (≥25 nm). Here, a green yet facile synthesis strategy using biocompatible liposomes as templates to mediate the formation of mesoporous metallic nanostructures in a controllable fashion is reported. Various monodispersed nanostructures with well-defined mesoporous shape and large mesopores (≈ 40 nm) are successfully synthesized from mono- (Au, Pd, and Pt), bi- (AuPd, AuPt, AuRh, PtRh, and PdPt), and tri-noble metals (AuPdRh, AuPtRh, and AuPdPt). Along with a successful demonstration of its effectiveness in synthesis of various mesoporous nanostructures, the possible mechanism of liposome-guided formation of such nanostructures via time sectioning of the synthesis process (monitoring time-resolved growth of mesoporous structures) and computational quantum molecular modeling (analyzing chemical interaction energy between metallic cations and liposomes at the enthalpy level) is also revealed. These mesoporous metallic nanostructures exhibit a strong photothermal effect in the near-infrared region, effective catalytic activities in hydrogen peroxide decomposition reaction, and high drug loading capacity. Thus, the liposome-templated method provides an inspiring and robust avenue to synthesize mesoporous noble metal-based nanostructures for versatile biomedical applications.

Photothermal performance of a novel carbon dot and its conjugate with disulfiram for prostate cancer PC3 cell therapy

Aim: To develop and employ a copper, sulfur, nitrogen-carbon quantum dot (C,S,N-CQD) multifunctional platform for synergistic cancer therapy, combining chemotherapy and photothermal treatment with in vitro cancer cell imaging. Materials & methods: Cu,S,N-CQDs were synthesized hydrothermally, loaded with disulfiram (DSF), and characterized through UV-Vis spectrophotometry, photoluminescence, Fourier-transform infrared spectroscopy, high-resolution transmission electron microscopy, dynamic light scattering, x-ray diffraction and EDAX. Results: Cu,S,N-CQD exhibited 5.5% absolute fluorescence quantum yield, 46.0% photothermal conversion efficiency and excellent stability. The release of DSF-loaded Cu,S,N-CQD, photothermal performance, and IC50 on PC3 prostate cancer cells, were evaluated. The impact of cellular glutathione on nanocarrier performance was investigated. Conclusion: Cu,S,N-CQD as a photothermal agent and DSF carrier showed synergy (combination index: 0.71) between chemotherapy and photothermal therapy. The nanocarrier simultaneously employed for in vitro cancer cell imaging due to its unique fluorescence properties.

A Novel Strategy to Improve Tumor Targeting of Hydrophilic Drugs and Nanoparticles for Imaging Guided Synergetic Therapy

The fast renal clearance of hydrophilic small molecular anticancer drugs and ultrasmall nanoparticles (NPs) results in the low utilization rate and certain side effects, thus improving the tumor targeting is highly desired but faces great challenges. A novel and general β-cyclodextrin (CD) aggregation-induced assembly strategy to fabricate doxorubicin (DOX) and CD-coated NPs (such as Au) co-encapsulated pH-responsive nanocomposites (NCs) is proposed. By adding DOX×HCl and reducing pH in a reversed microemulsion system, hydrophilic CD-coated AuNPs rapidly assemble into large NCs. Then in situ polymerization of dopamine and sequentially coordinating with Cu2+ on the surface of NCs provide extra weak acid responsiveness, chemodynamic therapy (CDT), and improved biocompatibility as well as stability. The subsequent tumor microenvironment responsive dissociation notably improves their passive tumor targeting, bioavailability, imaging, and therapeutic capabilities, as well as facilitates their internalization by tumor cells and metabolic clearance, thereby reducing side effects. The combination of polymerized dopamine and assembled AuNPs reinforces photothermal capability, thus further boosting CDT through thermally amplifying Cu-catalyzed Fenton-like reaction. Both in vitro and in vivo studies confirm the desirable outcomes of these NCs as photoacoustic imaging guided trimodal (thermally enhanced CDT, photothermal therapy, and chemotherapy) synergistic tumor treatment agents with minimal systemic toxicity.

A Versatile PDA(DOX) Nanoplatform for Chemo-Photothermal Synergistic Therapy against Breast Cancer and Attenuated Doxorubicin-Induced Cardiotoxicity

Photothermal therapy (PTT) is a highly clinical application promising cancer treatment strategy with safe, convenient surgical procedures and excellent therapeutic efficacy on superficial tumors. However, a single PTT is difficult to eliminate tumor cells completely, and tumor recurrence and metastasis are prone to occur in the later stage. Chemo-photothermal synergistic therapy can conquer the shortcomings by further killing residual tumor cells after PTT through systemic chemotherapy. Nevertheless, chemotherapy drugs' extreme toxicity is also a problematic issue to be solved, such as anthracycline-induced cardiotoxicity. Herein, we selected polydopamine nanoparticles (PDA) as the carrier of the chemotherapeutic drug doxorubicin (DOX) to construct a versatile PDA(DOX) nanoplatform for chemo-photothermal synergistic therapy against breast cancer and simultaneously attenuated DOX-induced cardiotoxicity (DIC). The excellent photothermal properties of PDA were used to achieve the thermal ablation of tumors. DOX carried out chemotherapy to kill residual and occult distant tumors. Furthermore, the PDA(DOX) nanoparticles significantly alleviate DIC, which benefits from PDA's excellent antioxidant enzyme activity. The experimental data of the chemotherapy groups showed that the results of the PDA(DOX) group were much better than the DOX group. This study not only effectively inhibits cancer but tactfully attenuates DIC, bringing a new perspective into synergistic therapy against breast cancer.

Fluorescence-free bis(dithiolene)nickel dyes for surface-enhanced resonance Raman imaging in the second near-infrared window

Second near-infrared window (NIR-II, 1000-1700 nm) imaging is one of the foremost optical imaging techniques. However, surface-enhanced Raman scattering (SERS)-based research in this optical region remains in its infancy, mainly because of a lack of suitable NIR-II Raman reporters. Herein, we report the first example of a nickel dithiolene complex as a NIR-II resonance Raman reporter with intense long wavelength absorption (ε = 9.58 × 104 m-1 cm-1 at 1007 nm), fluorescence-free features and ultrahigh affinity to noble metal surfaces with its eight sulfur atoms. Surface-enhanced resonance Raman scattering nanoprobes constructed with such reporters enable high contrast and highly photostable lymph node imaging far superior to that possible with existing NIR-I and NIR-II SERS nanoprobes. The developed NIR-II nanoprobes allow deep optical penetration (8 mm) as well as in vivo SERS detection of deep-seated microtumors in mice.

The Emerging Role of Raman Spectroscopy as an Omics Approach for Metabolic Profiling and Biomarker Detection toward Precision Medicine

Omics technologies have rapidly evolved with the unprecedented potential to shape precision medicine. Novel omics approaches are imperative toallow rapid and accurate data collection and integration with clinical information and enable a new era of healthcare. In this comprehensive review, we highlight the utility of Raman spectroscopy (RS) as an emerging omics technology for clinically relevant applications using clinically significant samples and models. We discuss the use of RS both as a label-free approach for probing the intrinsic metabolites of biological materials, and as a labeled approach where signal from Raman reporters conjugated to nanoparticles (NPs) serve as an indirect measure for tracking protein biomarkers in vivo and for high throughout proteomics. We summarize the use of machine learning algorithms for processing RS data to allow accurate detection and evaluation of treatment response specifically focusing on cancer, cardiac, gastrointestinal, and neurodegenerative diseases. We also highlight the integration of RS with established omics approaches for holistic diagnostic information. Further, we elaborate on metal-free NPs that leverage the biological Raman-silent region overcoming the challenges of traditional metal NPs. We conclude the review with an outlook on future directions that will ultimately allow the adaptation of RS as a clinical approach and revolutionize precision medicine.

NIR-II Responsive Nanohybrids Incorporating Thermosensitive Hydrogel as Sprayable Dressing for Multidrug-Resistant-Bacteria Infected Wound Management

Developing an effective dressing against bacterial infection and synchronously addressing wound complications, such as bleeding, long-term inflammation, and reinfection, are highly desirable in clinical practice. In this work, a second near-infrared (NIR-II) responsive nanohybrid consisting of imipenem encapsulated liposome with gold-shell and lipopolysaccharide (LPS)-targeting aptamer, namely ILGA, is constructed for bacteria elimination. Benefiting from the delicate structure, ILGA exhibits strong affinity and a reliable photothermal/antibiotic therapeutic effect toward multidrug-resistant Pseudomonas aeruginosa (MDR-PA). Furthermore, by incorporating ILGA with a thermosensitive hydrogel poly(lactic-co-glycolic acid)-polyethylene glycol-poly(lactic-co-glycolic acid) (PLGA-PEG-PLGA), a sprayable dressing ILGA@Gel was prepared, which enables a quick on-demand gelation (10 s) for wound hemostasis and offers excellent photothermal/antibiotic efficacy to sterilize the infected wound. Additionally, ILGA@Gel provides satisfactory wound-healing environments by reeducating wound-associated macrophages for inflammation alleviation and forming a gel layer to block exogenous bacterial reinfection. This biomimetic hydrogel reveals excellent bacteria eradication and wound recovery effectiveness, demonstrating its promising potential for managing complicated infected wounds.

Carbon dots-mediated synthesis of gold nanodendrites with extended absorption into NIR-II window for in vivo photothermal therapy

BACKGROUND

Photothermal therapy (PTT) in the second near-infrared (NIR-II) window has attracted extensive attention due to the benefits in high maximum permissible exposure and penetration depth. Current photothermal agents generally show a broadband absorption accompanied by a gradual attenuation of absorption in the NIR-II window, leading to poor effect of PTT. It remains a great challenge to gain photothermal agents with strong and characteristic absorption in NIR-II regions. To overcome this problem, based on carbon dots (CDs)-mediated growth strategy, we proposed a simple and feasible approach to prepare plasmonic gold nanodendrites (AuNDs) with NIR-II absorption to enhance the therapeutic effect of PTT.

RESULTS

By rationally regulating the size and branch length of AuNDs, the AuNDs exhibited a broadband absorption from 300 to 1350 nm, with two characteristic absorption peaks located at 1077 and 1265 nm. The AuNDs demonstrated desired optical photothermal conversion efficiency (38.0%), which was further applied in NIR-II photoacoustic imaging (PAI) and PTT in human colon cancer cells (HCT 116)-tumor-bearing mice model. The tumor cells could be effectively eliminated in vivo under 1064 nm laser irradiation by the guidance of PAI.

CONCLUSIONS

We reported a simple but powerful synthetic method to obtain the unique AuNDs with strong and characteristic absorption peaks in the NIR-II window. This study provides a promising solution to tuning the growth of nanoparticles for bioimaging and phototherapy in the NIR-II window.

Second Near-Infrared Plasmonic Nanomaterials for Photoacoustic Imaging and Photothermal Therapy

Photoacoustic imaging (PAI) and imaging-guided photothermal therapy (PTT) in the second near-infrared window (NIR-II, 1000-1700 nm) have received increasing attention owing to their advantages of greater penetration depth and higher signal-to-noise ratio. Plasmonic nanomaterials with tunable optical properties and strong light absorption provide an alternative to dye molecules, showing great prospects for phototheranostic applications. In this review, the research progress in principally modulating the optical properties of plasmonic nanomaterials, especially affecting parameters such as size, morphology, and surface chemical modification, is introduced. The commonly used plasmonic nanomaterials in the NIR-II window, including noble metals, semiconductors, and heterostructures, are then summarized. In addition, the biomedical applications of these NIR-II plasmonic nanomaterials for PAI and PTT in phototheranostics are highlighted. Finally, the perspectives and challenges for advancing plasmonic nanomaterials for practical use and clinical translation are discussed.

Enzyme/GSH/pH-responsive hyaluronic acid grafted porous silica nanocarriers bearing Ag2S QDs for fluorescence imaging and combined therapy

Hyaluronic acid (HA) is a naturally polysaccharide that has been used for drug delivery, but is limited by low drug loading capacity and drug leakage in circulation. To improve drug delivery efficient, HA modified porous silica (pSiO₂) nanocarriers were successfully prepared for drug delivery and combining therapy. pSiO₂ nanocarriers have stable porous structure and high loading capacity, and pSiO₂/HA nanocarriers would possess advantages of HA-based carriers and pSiO₂ nanoparticles. Herein, pSiO₂ nanocarriers were prepared by two-phase process, followed by embedding Ag₂S QDs in the pore walls of pSiO₂ carriers, which render the carriers photothermal effect. pSiO₂ nanocarriers have size of 30 nm, large channels, and high loading capacity (29.3 %). To graft HA, a sensitive linker with alkyl amine and disulfide bond was conjugated on the surface of Ag₂S/pSiO₂ nanocarriers by three-step reaction. After loading doxorubicin (DOX), HA was grafted via sensitive linker onto the surface of Ag₂S/pSiO₂ carriers via the formation of amide bonds to seal the loaded drugs. The interaction between HA and CD44 confers the carrier targeting ability to cancer cells. HA coating can be degraded by hyaluronidase resulting in the release of internal cargo. The Ag₂S/pSiO₂/HA nanocarriers performs responsive drug release and combining photothermal chemotherapy.

Tracking tumor heterogeneity and progression with near-infrared II fluorophores

Heterogeneous cells are the main feature of tumors with unique genetic and phenotypic characteristics, which can stimulate differentially the progression, metastasis, and drug resistance. Importantly, heterogeneity is pervasive in human malignant tumors, and identification of the degree of tumor heterogeneity in individual tumors and progression is a critical task for tumor treatment. However, current medical tests cannot meet these needs; in particular, the need for noninvasive visualization of single-cell heterogeneity. Near-infrared II (NIR-II, 1000-1700 nm) imaging exhibits an exciting prospect for non-invasive monitoring due to the high temporal-spatial resolution. More importantly, NIR-II imaging displays more extended tissue penetration depths and reduced tissue backgrounds because of the significantly lower photon scattering and tissue autofluorescence than traditional the near-infrared I (NIR-I) imaging. In this review, we summarize systematically the advances made in NIR-II in tumor imaging, especially in the detection of tumor heterogeneity and progression as well as in tumor treatment. As a non-invasive visual inspection modality, NIR-II imaging shows promising prospects for understanding the differences in tumor heterogeneity and progression and is envisioned to have the potential to be used clinically.

Second Near-Infrared (NIR-II) Window for Imaging-Navigated Modulation of Brain Structure and Function

For a long time, optical imaging of the deep brain with high resolution has been a challenge. Recently, with the advance in second near-infrared (NIR-II) bioimaging techniques and imaging contrast agents, NIR-II window bioimaging has attracted great attention to monitoring deeper biological or pathophysiological processes with high signal-to-noise ratio (SNR) and spatiotemporal resolution. Assisted with NIR-II bioimaging, the modulation of structure and function of brain is promising to be noninvasive and more precise. Herein, in this review, first the advantage of NIR-II light in brain imaging from the interaction between NIR-II and tissue is elaborated. Then, several specific NIR-II bioimaging technologies are introduced, including NIR-II fluorescence imaging, multiphoton fluorescence imaging, and photoacoustic imaging. Furthermore, the corresponding contrast agents are summarized. Next, the application of various NIR-II bioimaging technologies in visualizing the characteristics of cerebrovascular network and monitoring the changes of the pathology signals will be presented. After that, the modulation of brain structure and function based on NIR-II bioimaging will be discussed, including treatment of glioblastoma, guidance of cell transplantation, and neuromodulation. In the end, future perspectives that would help improve the clinical translation of NIR-II light are proposed.

Hyaluronic acid-covered piezoelectric nanocomposites as tumor microenvironment modulators for piezoelectric catalytic therapy of melanoma

Increasing the formation of reactive oxygen species (ROS) and reducing the elimination of ROS are the two main objectives in the development of novel inorganic sonosensitizers for use in sonodynamic therapy (SDT). Therefore, BTO-Pd-MnO₂-HA nanocomplexes with targeted tumor cells and degradable oxygen-producing shells were designed as piezoelectric sonosensitizers for enhancing SDT. The deposition of palladium particles (Pd NPs) leads to the formation of Schottky junctions, promoting the separation of electron-hole pairs and thereby increasing the efficiency of toxic ROS generation in SDT. The tumor microenvironment (TME) triggers the degradation of MnO₂, and the released Mn²⁺ ions catalyze the generation of hydroxyl radicals (•OH) from H₂O₂ through a Fenton-like reaction. BTO-Pd-MnO₂-HA can continuously consume glutathione (GSH) and generate O₂, thereby improving the efficiency of SDT and chemodynamic therapy (CDT). A multistep enhanced SDT process mediated by the piezoelectric sonosensitizers BTO-Pd-MnO₂-HA was designed, targeted by hyaluronic acid (HA), activated by decomposition in TME, and amplified by deposition of Pd. This procedure not only presents a new alternative for the improvement of sonosensitizers but also widens the application of piezoelectric nanomaterials in biomedicine.

Oxygen vacancy-enhanced catalytic activity of hyaluronic acid covered-biomineralization nanozyme for reactive oxygen species-augmented antitumor therapy

Insufficient hydrogen peroxide content in tumor cells, unsuitable pH and low efficiency of commonly used metal catalysts severely affect the efficiency of chemodynamic therapy, resulting in unsatisfactory efficacy of chemodynamic therapy alone. For this purpose, we designed a composite nanoplatform capable of targeting tumors and selectively degrading in the tumor microenvironment (TME) to address these issues. In this work, we synthesized Au@Co₃O₄ nanozyme inspired by crystal defect engineering. The addition of Au determines the formation of oxygen vacancies, accelerates electron transfer, and enhances redox activity, thus significantly enhancing the superoxide dismutase (SOD)-like and catalase (CAT)-like catalytic activities of the nanozyme. Subsequently, we camouflaged the nanozyme using a biomineralized CaCO₃ shell to avoid damage to normal tissues by the nanozyme while effectively encapsulating the photosensitizer IR820, and finally the tumor targeting ability of the nanoplatform was enhanced by the modification of hyaluronic acid. Under near-infrared (NIR) light irradiation, the Au@Co₃O₄@CaCO₃/IR820@HA nanoplatform not only visualizes the treatment with multimodal imaging, but also plays a photothermal sensitizing role through various strategies, while enhancing the enzyme catalytic activity, cobalt ion-mediated chemodynamic therapy (CDT) and IR820-mediated photodynamic therapy (PDT), and achieving the synergistic enhancement of reactive oxygen species (ROS) generation.

Design and Synthesis of SERS Materials for In Vivo Molecular Imaging and Biosensing

Surface-enhanced Raman scattering (SERS) is a feasible and ultra-sensitive method for biomedical imaging and disease diagnosis. SERS is widely applied to in vivo imaging due to the development of functional nanoparticles encoded by Raman active molecules (SERS nanoprobes) and improvements in instruments. Herein, the recent developments in SERS active materials and their in vivo imaging and biosensing applications are overviewed. Various SERS substrates that have been successfully used for in vivo imaging are described. Then, the applications of SERS imaging in cancer detection and in vivo intraoperative guidance are summarized. The role of highly sensitive SERS biosensors in guiding the detection and prevention of diseases is discussed in detail. Moreover, its role in the identification and resection of microtumors and as a diagnostic and therapeutic platform is also reviewed. Finally, the progress and challenges associated with SERS active materials, equipment, and clinical translation are described. The present evidence suggests that SERS could be applied in clinical practice in the future.

Targeted Lymphoma Therapy Using a Gold Nanoframework-Based Drug Delivery System

Precision nanomedicine can be employed as an alternative to chemo- or radiotherapy to overcome challenges associated with the often narrow therapeutic window of traditional treatment approaches, while safely inducing effective, targeted antitumor responses. Herein, we report the formulation of a therapeutic nanocomposite comprising a hyaluronic acid (HA)-coated gold nanoframework (AuNF) delivery system and encapsulated IT848, a small molecule with potent antilymphoma and -myeloma properties that targets the transcriptional activity of nuclear factor kappa B (NF-κB). The porous AuNFs fabricated via a liposome-templated approach were loaded with IT848 and surface-functionalized with HA to formulate the nanotherapeutics that were able to efficiently deliver the payload with high specificity to myeloma and lymphoma cell lines in vitro. In vivo studies characterized biodistribution, pharmacokinetics, and safety of HA-AuNFs, and we demonstrated superior efficacy of HA-AuNF-formulated IT848 vs free IT848 in lymphoma mouse models. Both in vitro and in vivo results affirm that the AuNF system can be adopted for targeted cancer therapy, improving the drug safety profile, and enhancing its efficacy with minimal dosing. HA-AuNF-formulated IT848 therefore has strong potential for clinical translation.

Genetically edited T-cell membrane coated AIEgen nanoparticles effectively prevents glioblastoma recurrence

Glioblastoma stem cells (GSCs) are subpopulations of tumor-initiating cells responsible for glioblastoma (GBM) tumorigenesis and recurrence. Dual inhibition of vascular endothelium and GSCs is still a challenge due to their different pathological features. Here we present a combined all-in-control strategy to realize a local photothermal therapy (PTT). We designed T-cell-mimic nanoparticles with aggregation-induced emission (AIE) characteristics by coating the genetically engineered T cell membrane (CM) onto AIE nanoparticles (CM@AIE NPs). The CM shell was designed against CD133 and epidermal growth factor receptor (EGFR) which provides the possibility to target both GBM cells and GSCs for cancer therapy. CM@AIE NPs can serve as the tight junction (TJ) modulators to trigger an intracellular signaling cascade, causing TJ disruption and actin cytoskeleton reorganization to allow CM@AIE NPs to cross the blood-brain barrier (BBB) silently. The 980 nm excitation-triggered PTT can completely inhibit tumorigenesis and recurrence. The combination of CM-coating nanotechnology and genetic editing technique can inspire further development of synergetic techniques for preventing GBM recurrence.

Recent Advances in Contrast-Enhanced Photoacoustic Imaging: Overcoming the Physical and Practical Challenges

For decades now, photoacoustic imaging (PAI) has been investigated to realize its potential as a niche biomedical imaging modality. Despite its highly desirable optical contrast and ultrasonic spatiotemporal resolution, PAI is challenged by such physical limitations as a low signal-to-noise ratio (SNR), diminished image contrast due to strong optical attenuation, and a lower-bound on spatial resolution in deep tissue. In addition, contrast-enhanced PAI has faced practical limitations such as insufficient cell-specific targeting due to low delivery efficiency and difficulties in developing clinically translatable agents. Identifying these limitations is essential to the continuing expansion of the field, and substantial advances in developing contrast-enhancing agents, complemented by high-performance image acquisition systems, have synergistically dealt with the challenges of conventional PAI. This review covers the past four years of research on pushing the physical and practical challenges of PAI in terms of SNR/contrast, spatial resolution, targeted delivery, and clinical application. Promising strategies for dealing with each challenge are reviewed in detail, and future research directions for next generation contrast-enhanced PAI are discussed.

Innovative nanotheranostics: Smart nanoparticles based approach to overcome breast cancer stem cells mediated chemo- and radioresistances

The alarming increase in the number of breast cancer patients worldwide and the increasing death rate indicate that the traditional and current medicines are insufficient to fight against it. The onset of chemo- and radioresistances and cancer stem cell-based recurrence make this problem harder, and this hour needs a novel treatment approach. Competent nanoparticle-based accurate drug delivery and cancer nanotheranostics like photothermal therapy, photodynamic therapy, chemodynamic therapy, and sonodynamic therapy can be the key to solving this problem due to their unique characteristics. These innovative formulations can be a better cargo with fewer side effects than the standard chemotherapy and can eliminate the stability problems associated with cancer immunotherapy. The nanotheranostic systems can kill the tumor cells and the resistant breast cancer stem cells by novel mechanisms like local hyperthermia and reactive oxygen species and prevent tumor recurrence. These theranostic systems can also combine with chemotherapy or immunotherapy approaches. These combining approaches can be the future of anticancer therapy, especially to overcome the breast cancer stem cells mediated chemo- and radioresistances. This review paper discusses several novel theranostic systems and smart nanoparticles, their mechanism of action, and their modifications with time. It explains their relevance and market scope in the current era. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Tea leaf-derived exosome-like nanotherapeutics retard breast tumor growth by pro-apoptosis and microbiota modulation

While several artificial nanodrugs have been approved for clinical treatment of breast tumor, their long-term applications are restricted by unsatisfactory therapeutic outcomes, side reactions and high costs. Conversely, edible plant-derived natural nanotherapeutics (NTs) are source-widespread and cost-effective, which have been shown remarkably effective in disease treatment. Herein, we extracted and purified exosome-like NTs from tea leaves (TLNTs), which had an average diameter of 166.9 nm and a negative-charged surface of - 28.8 mV. These TLNTs contained an adequate slew of functional components such as lipids, proteins and pharmacologically active molecules. In vitro studies indicated that TLNTs were effectively internalized by breast tumor cells (4T1 cells) and caused a 2.5-fold increase in the amount of intracellular reactive oxygen species (ROS) after incubation for 8 h. The high levels of ROS triggered mitochondrial damages and arrested cell cycles, resulting in the apoptosis of tumor cells. The mouse experiments revealed that TLNTs achieved good therapeutic effects against breast tumors regardless of intravenous injection and oral administration through direct pro-apoptosis and microbiota modulation. Strikingly, the intravenous injection of TLNTs, not oral administration, yielded obvious hepatorenal toxicity and immune activation. These findings collectively demonstrate that TLNTs can be developed as a promising oral therapeutic platform for the treatment of breast cancer.

Copperphosphotungstate Doped Polyanilines Nanorods for GSH-Depletion Enhanced Chemodynamic/NIR-II Photothermal Synergistic Therapy

Introduction

The high concentration of glutathione (GSH) and hydrogen peroxide (H₂O₂) levels within the tumor microenvironment (TME) are the major obstacle to induce the unsatisfactory anticancer treatment efficiency. The synergistic cancer therapy strategies of the combination the GSH depletion enhanced chemodynamic therapy (CDT) with photothermal therapy (PTT) have been proved to be the promising method to significantly improve the therapeutic efficacy.

Methods

The copperphosphotungstate was incorporated into polyanilines to design copperphosphotungstate doped polyaniline nanorods (CuPW@PANI Nanorods) via chemical oxidant polymerization of aniline. The low long-term toxicity and biocompatibility were evaluated. Both in vitro and in vivo experiments were carried out to confirm the GSH depletion enhanced CDT/NIR-II PTT synergistic therapy.

Results

CuPW@PANI Nanorods feature biosafety and biocompatibility, strong NIR-II absorbance, and high photothermal-conversion efficiency (45.14%) in NIR-II bio-window, making them highly applicable for photoacoustic imaging and NIR-II PTT. Moreover, CuPW@PANI Nanorods could consume endogenous GSH to disrupt redox homeostasis and perform a Fenton-like reaction with H₂O₂ to produce cytotoxic •OH for the enhanced CDT. Furthermore, NIR-II photothermal-induced local hyperthermia accelerates •OH generation to enhance CDT, which realizes high therapeutic efficacy in vivo.

Conclusion

This study provides a proof of concept of GSH-depletion augmented chemodynamic/NIR-II photothermal therapy.

Synergistic Reinforcing of Immunogenic Cell Death and Transforming Tumor-Associated Macrophages Via a Multifunctional Cascade Bioreactor for Optimizing Cancer Immunotherapy

Immunogenic cell death (ICD) has aroused widespread attention because it can reconstruct a tumor microenvironment and activate antitumor immunity. This study proposes a two-way enhancement of ICD based on a CaO₂ @CuS-MnO₂ @HA (CCMH) nanocomposite to overcome the insufficient damage-associated molecular patterns (DAMPs) of conventional ICD-inducers. The near-infrared (NIR) irradiation (1064 nm) of CuS nanoparticles generates ¹ O₂ through photodynamic therapy (PDT) to trigger ICD, and it also damages the Ca²⁺ buffer function of mitochondria. Additionally, CaO₂ nanoparticles react with H₂ O to produce a large amount of O₂ and Ca²⁺ , which respectively lead to enhanced PDT and Ca²⁺ overload during mitochondrial damage, thereby triggering a robust ICD activation. Moreover, oxidative-damaged mitochondrial DNA, induced by PDT and released from tumor cells, reprograms the immunosuppressive tumor microenvironment by transforming tumor-associated macrophages to the M1 subphenotype. This study shows that CCMH with NIR-II irradiation can elicit adequate DAMPs and an active tumor-immune microenvironment for both 4T1 and CT26 tumor models. Combining this method with an immune checkpoint blockade can realize an improved immunotherapy efficacy and long-term protection effect for body.

Phosphotungstate Acid Doped Polyanilines Nanorods for in situ NIR-II Photothermal Therapy of Orthotopic Hepatocellular Carcinoma in Rabbit

Introduction

Second near-infrared photothermal therapy (NIR-II PTT) has become a promising strategy for treating cancer in terms of safety and potency. However, the application of NIR-II PTT was limited in the treatment of deep-buried solid tumors due to the low dose of NIR-II absorption nanomaterials and the inadequate laser energy in the deep tumor.

Methods

Herein, the authors report the engineering of NIR-II absorbing polyaniline nanorods, termed HPW@PANI Nanorods, for in situ NIR-II PTT based on optical fibers transmission of laser power and transarterial infusion for the treatment of orthotopic hepatocellular carcinoma in the rabbit. HPW@PANI Nanorods were prepared via chemical oxidant polymerization of aniline under phosphotungstic acid, which exhibited effective NIR-II absorption for hyperthermia ablation cells.

Results

HPW@PANI Nanorods were fast and efficiently deposited into primary orthotopic transplantation VX2 tumor in rabbits via transarterial infusion. Furthermore, an optical fiber was interventionally inserted into the primary VX2 tumor to transmit 1064nm laser energy for in situ NIR-II PTT, which could ablate primary tumor, inhibit distant tumor, and suppress peritoneal metastasis.

Conclusion

This study provides new insights into the application of in situ NIR-II PTT based on optical fibers transmission of laser power and transarterial injection of NIR-II absorption nanomaterials to treat deep-buried tumors.

Biomedical Photoacoustic Imaging for Molecular Detection and Disease Diagnosis: "Always-On" and "Turn-On" Probes

Photoacoustic (PA) imaging is a nonionizing, noninvasive imaging technique that combines optical and ultrasonic imaging modalities to provide images with excellent contrast, spatial resolution, and penetration depth. Exogenous PA contrast agents are created to increase the sensitivity and specificity of PA imaging and to offer diagnostic information for illnesses. The existing PA contrast agents are categorized into two groups in this review: "always-on" and "turn-on," based on their ability to be triggered by target molecules. The present state of these probes, their merits and limitations, and their future development, is explored.

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

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

Recent advances in porous nanomaterials-based drug delivery systems for cancer immunotherapy

Cancer immunotherapy is a novel therapeutic regimen because of the specificity and durability of immune modulations to treat cancers. Current cancer immunotherapy is limited by some barriers such as poor response rate, low tumor specificity and systemic toxicities. Porous nanomaterials (PNMs) possess high loading capacity and tunable porosity, receiving intense attention in cancer immunotherapy. Recently, novel PNMs based drug delivery systems have been employed in antitumor immunotherapy to enhance tissue or organ targeting and reduce immune-related adverse events. Herein, we summarize the recent progress of PNMs including inorganic, organic, and organic–inorganic hybrid ones for cancer immunotherapy. The design of PNMs and their performance in cancer immunotherapy are discussed in detail, with a focus on how those designs can address the challenges in current conventional immunotherapy. Lastly, we present future directions of PNMs for cancer immunotherapy including the challenges and research gaps, providing new insights about the design of PNMs for efficient cancer immunotherapy with better performance as powerful weapons against tumors. Finally, we discussed the relevant challenges that urgently need to be addressed in clinical practice, coupled with corresponding solutions to these problems.

Biomimetic Lipopolysaccharide-Free Bacterial Outer Membrane-Functionalized Nanoparticles for Brain-Targeted Drug Delivery

The blood-brain barrier (BBB) severely blocks the intracranial accumulation of most systemic drugs. Inspired by the contribution of the bacterial outer membrane to Escherichia coli K1 (EC-K1) binding to and invasion of BBB endothelial cells in bacterial meningitis, utilization of the BBB invasion ability of the EC-K1 outer membrane for brain-targeted drug delivery and construction of a biomimetic self-assembled nanoparticle with a surface featuring a lipopolysaccharide-free EC-K1 outer membrane are proposed. BBB penetration of biomimetic nanoparticles is demonstrated to occur through the transcellular vesicle transport pathway, which is at least partially dependent on internalization, endosomal escape, and transcytosis mediated by the interactions between outer membrane protein A and gp96 on BBB endothelial cells. This biomimetic nanoengineering strategy endows the loaded drugs with prolonged circulation, intracranial interstitial distribution, and extremely high biocompatibility. Based on the critical roles of gp96 in cancer biology, this strategy reveals enormous potential for delivering therapeutics to treat gp96-overexpressing intracranial malignancies.

Listening to drug delivery and responses via photoacoustic imaging

Administrating pharmaceutic agents efficiently to achieve the therapeutic effect is the aim of all drug delivery techniques. Recent drug delivery systems aim to deliver high doses of drugs to disease sites accurately while maximizing therapeutic effects and minimizing potential side effects. Key approaches apply image guidance techniques for the quantification of drug biodistribution and pharmacokinetic parameters during drug delivery. This review highlights recent research on image-guided drug delivery systems based on photoacoustic imaging, which has been attracting attention for its non-invasiveness, non-ionizing radiation, and real-time imaging functions. Photoacoustic imaging based on the photothermal conversion efficiency of agents can be easily combined with various phototherapeutics, making them highly suitable for drug delivery therapy platforms. Here, we summarize and compare the characteristics of various types of photoacoustic imaging systems, focus on contrast-enhanced photoacoustic imaging and controlled release of therapeutics in drug delivery systems for synergistic therapies.

Smart PdH@MnO2 Yolk-Shell Nanostructures for Spatiotemporally Synchronous Targeted Hydrogen Delivery and Oxygen-Elevated Phototherapy of Melanoma

Hydrogen therapy, an emerging therapeutic strategy, has recently attracted much attention in anticancer medicine. Evidence suggests that hydrogen (H₂) can selectively reduce intratumoral overexpressed hydroxyl radicals (•OH) to break the redox homeostasis and thereby lead to redox stress and cell damage. However, the inability to achieve stable hydrogen storage and efficient hydrogen delivery hinders the development of hydrogen therapy. Furthermore, oxygen (O₂) deficiency in the tumor microenvironment (TME) and the electron-hole separation inefficiency in photosensitizers have severely limited the efficacy of photodynamic therapy (PDT). Herein, a smart PdH@MnO₂/Ce6@HA (PHMCH) yolk-shell nanoplatform is designed to surmount these challenges. PdH tetrahedrons combine stable hydrogen storage and high photothermal conversion efficiency of palladium (Pd) nanomaterials with near-infrared-controlled hydrogen release. Subsequently, the narrow bandgap semiconductor manganese dioxide (MnO₂) and the photosensitizer chlorin e6 (Ce6) are introduced into the PHMCH nanoplatform. Upon irradiation, the staggered energy band edges in heterogeneous materials composed of MnO₂ and Ce6 can efficiently facilitate electron-hole separation for increasing singlet oxygen (¹O₂). Moreover, MnO₂ nanoshells generate O₂ in TME for ameliorating hypoxia and further improving O₂-dependent PDT. Finally, the hyaluronic acid-modified PHMCH nanoplatform shows negligible cytotoxicity and selectively targets CD44-overexpressing melanoma cells. The synergistic antitumor performance of the H₂-mediated gas therapy combined with photothermal and enhanced PDT can explore more possibilities for the design of gas-mediated cancer therapy.

Engineering single-atom catalysts toward biomedical applications

Due to inherent structural defects, common nanocatalysts always display limited catalytic activity and selectivity, making it practically difficult for them to replace natural enzymes in a broad scope of biologically important applications. By decreasing the size of the nanocatalysts, their catalytic activity and selectivity will be substantially improved. Guided by this concept, the advances of nanocatalysts now enter an era of atomic-level precise control. Single-atom catalysts (denoted as SACs), characterized by atomically dispersed active sites, strikingly show utmost atomic utilization, precisely located metal centers, unique metal-support interactions and identical coordination environments. Such advantages of SACs drastically boost the specific activity per metal atom, and thus provide great potential for achieving superior catalytic activity and selectivity to functionally mimic or even outperform natural enzymes of interest. Although the size of the catalysts does matter, it is not clear whether the guideline of "the smaller, the better" is still correct for developing catalysts at the single-atom scale. Thus, it is clearly a new, urgent issue to address before further extending SACs into biomedical applications, representing an important branch of nanomedicine. This review begins by providing an overview of recent advances of synthesis strategies of SACs, which serve as a basis for the discussion of emerging achievements in improving the enzyme-like catalytic properties at an atomic level. Then, we carefully compare the structures and functions of catalysts at various scales from nanoparticles, nanoclusters, and few-atom clusters to single atoms. Contrary to conventional wisdom, SACs are not the most catalytically active catalysts in specific reactions, especially those requiring multi-site auxiliary activities. After that, we highlight the unique roles of SACs toward biomedical applications. To appreciate these advances, the challenges and prospects in rapidly growing studies of SACs-related catalytic nanomedicine are also discussed in this review.

Self-Rectifiable and Hypoxia-Assisted Chemo-Photodynamic Nanoinhibitor for Synergistic Cancer Therapy

Photodynamic therapy (PDT) can eradicate cancer cells under light irradiation, mainly because of reactive singlet oxygen (¹O₂) being transformed from intratumoral oxygen. Nonetheless, the consumption of oxygen during PDT results in serious hypoxic conditions and an elevated hypoxia-inducing factor-1α (HIF-1α) level that hamper further photodynamic efficacy and induce tumor metastasis. To address this problem, we developed hypoxia-assisted NP-co-encapsulating Ce6 (photosensitizer) and YC-1 (HIF-1α inhibitor) as a self-rectifiable nanoinhibitor for synergistic antitumor treatment. PDT-aggravated intracellular hypoxic stress facilitated NP dissociation to release the drug (YC-1), which achieved tumor killing and HIF-1α inhibition to further enhance the therapeutic effect of PDT and prevent tumor metastasis. Besides, in vivo studies revealed that the HC/PI@YC-1 NPs afforded synergistic anticancer efficacy with minimal toxicity. Therefore, this study provides a prospective approach against PDT drawbacks and combination cancer therapy.

Surface-enhanced Raman probes based on gold nanomaterials for in vivo diagnosis and imaging

Surface-enhanced Raman scattering (SERS) has received considerable attention from researchers due to its high molecular specificity, high sensitivity, non-invasive and multiplexing. Recently, various metal substrates have been exploited for SERS analysis and imaging. Among them, gold nanomaterials are important SERS substrates with outstanding surface plasmon resonance effects, structural adjustability and good biocompatibility, making them widely used in biomedical diagnosis and clinical fields. In this minireview, we discuss the latest progress about the application of gold-based nanomaterials as SERS probes in biomedical research, primarily for in vivo disease diagnosis and imaging. This review mainly includes the basic shapes and morphologies of gold based SERS probes, such as gold nanoparticles (AuNPs), gold nanorods (AuNRs), gold nanostars (AuNSs), as well as other gold nanostructures. Finally, a brief outlook for the future development of SERS technique in the context of efficient diagnostics and therapy guidance is provided. We hope that this minireview will facilitate the design and future development of Surface-enhanced Raman probes based on gold nanomaterials.

NIR-II Functional Materials for Photoacoustic Theranostics

Photoacoustic imaging (PAI) has attracted great attention in the diagnosis and treatment of diseases due to its noninvasive properties. Especially in the second near-infrared (NIR-II) window, PAI can effectively avoid the interference of tissue spontaneous fluorescence and light scattering, and obtain high resolution images with deeper penetration depth. Because of its ideal spectral absorption and high conversion efficiency, NIR-II PA contrast agents overcome the absorption or emission of NIR-II light by endogenous biomolecules. In recent years, a series of NIR-II PA contrast agents have been developed to improve the performance of PAI in disease diagnosis and treatment. In this paper, the research progress of NIR-II PA contrast agents and their applications in biomedicine are reviewed. PA contrast agents are classified according to their composition, including inorganic contrast agents, organic contrast agents, and hybrid organic-inorganic contrast agents. The applications of NIR-II PA contrast agents in medical imaging are described, such as cancer imaging, inflammation detection, brain disease imaging, blood related disease imaging, and other biomedical application. Finally, the research prospects and breakthrough of NIR-II PA contrast agents are discussed.

Au-on-Ag nanostructure forin-situSERS monitoring of catalytic reactions

Dual-functionality Au-on-Ag nanostructures (AOA) were fabricated on a silicon substrate by first immobilizing citrate-reduced Ag nanoparticles (Ag NPs, ∼43 nm in diameter), followed by depositing ∼7 nm Au nanofilms (Au NFs) via thermal evaporation. Au NFs were introduced for their catalytic activity in concave-convex nano-configuration. Ag NPs underneath were used for their significant enhancement factor (EF) in surface-enhanced Raman scattering (SERS)-based measurements of analytes of interest. Rhodamine 6G (R6G) was utilized as the Raman-probe to evaluate the SERS sensitivity of AOA. The SERS EF of AOA is ∼37 times than that of Au NPs. Using reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH₄) as a model reaction, we demonstrated the robust catalytic activity of AOA as well as its capacity to continuously monitor via SERS the disappearance of reactant 4-NTP, emergence and disappearance of intermediate 4,4'-DMAB, and the appearance of product 4-ATP throughout the reduction process in real-time andin situ.