Preparation of near-infrared photoacoustic imaging and photothermal treatment agent for cancer using a modifiable acid-triggered molecular platform.

Ratiometric near-infrared fluorescent pH probes with various pKa values were innovatively designed and synthesized based on cyanine with a diamine moiety. The photochemical properties of these probes were thoroughly evaluated. Among the series, IR-PHA exhibited an optimal pKa value of approximately 6.40, closely matching the pH of cancerous tissues. This feature is particularly valuable for real-time pH monitoring in both living cells and living mice. Moreover, when administered intravenously to tumor-bearing mice, IR-PHA demonstrated rapid and significant enhancement of near-infrared fluorescence and photoacoustic signals within the tumor region. This outcome underscores the probe's exceptional capability for dual-modal cancer imaging utilizing near-infrared fluorescence (NIRF) and photoacoustic (PA) modalities. Concurrently, the application of a continuous-wave near-infrared laser efficiently ablated cancer cells in vivo, attributed to the photothermal effect induced by IR-PHA. The results strongly indicate that IR-PHA is well-suited for NIRF/PA dual-modality imaging and photothermal therapy of tumors. This makes it a promising candidate for theranostic applications involving small molecules.

Cryomicroneedle delivery of nanogold-engineered Rhodospirillum rubrum for photochemical transformation and tumor optical biotherapy.

Tumor metabolite regulation is intricately linked to cancer progression. Because lactate is a characteristic metabolite of the tumor microenvironment (TME), it supports tumor progression and drives immunosuppression. In this study, we presented a strategy for antitumor therapy by developing a nanogold-engineered Rhodospirillum rubrum (R.r-Au) that consumed lactate and produced hydrogen for optical biotherapy. We leveraged a cryogenic micromolding approach to construct a transdermal therapeutic cryomicroneedles (CryoMNs) patch integrated with R.r-Au to efficiently deliver living bacterial drugs. Our long-term storage studies revealed that the viability of R.r-Au in CryoMNs remained above 90%. We found that the CryoMNs patch was mechanically strong and could be inserted into mouse skin. In addition, it rapidly dissolved after administering bacterial drugs and did not produce by-products. Under laser irradiation, R.r-Au effectively enhanced electron transfer through Au NPs actuation into the photosynthetic system of R. rubrum and enlarged lactate consumption and hydrogen production, thus leading to an improved tumor immune activation. Our study demonstrated the potential of CryoMNs-R.r-Au patch as a minimally invasive in situ delivery approach for living bacterial drugs. This research opens up new avenues for nanoengineering bacteria to transform tumor metabolites into effective substances for tumor optical biotherapy.

T cell cascade regulation initiates systemic antitumor immunity through living drug factory of anti-PD-1/IL-12 engineered probiotics.

Immune checkpoint blockade (ICB) has revolutionized cancer therapy but only works in a subset of patients due to the insufficient infiltration, persistent exhaustion, and inactivation of T cells within a tumor. Herein, we develop an engineered probiotic (interleukin [IL]-12 nanoparticle Escherichia coli Nissle 1917 [INP-EcN]) acting as a living drug factory to biosynthesize anti-PD-1 and release IL-12 for initiating systemic antitumor immunity through T cell cascade regulation. Mechanistically, INP-EcN not only continuously biosynthesizes anti-PD-1 for relieving immunosuppression but also effectively cascade promote T cell activation, proliferation, and infiltration via responsive release of IL-12, thus reaching a sufficient activation threshold to ICB. Tumor targeting and colonization of INP-EcNs dramatically increase local drug accumulations, significantly inhibiting tumor growth and metastasis compared to commercial inhibitors. Furthermore, immune profiling reveals that anti-PD-1/IL-12 efficiently cascade promote antitumor effects in a CD8+ T cell-dependent manner, clarifying the immune interaction of ICB and cytokine activation. Ultimately, such engineered probiotics achieve a potential paradigm shift from T cell exhaustion to activation and show considerable promise for antitumor bio-immunotherapy.

Rechargeable Afterglow Nanotorches for In Vivo Tracing of Cell-Based Microrobots.

As one of the self-luminescence imaging approaches that require pre-illumination instead of real-time light excitation, afterglow luminescence imaging has attracted increasing enthusiasm to circumvent tissue autofluorescence. In this work, we developed organic afterglow luminescent nanoprobe (nanotorch), which could emit persistent luminescence more than 10 days upon single light excitation. More importantly, the nanotorch could be remote charged by 660 nm light in a non-invasive manner, which showed great potential for real-time tracing the location of macrophage cell-based microrobots.

Bioorthogonal/Ultrasound Activated Oncolytic Pyroptosis Amplifies In Situ Tumor Vaccination for Boosting Antitumor Immunity.

Personalized in situ tumor vaccination is a promising immunotherapeutic modality. Currently, seeking immunogenic cell death (ICD) to generate in situ tumor vaccines is still mired by insufficient immunogenicity and an entrenched immunosuppressive tumor microenvironment (TME). Herein, a series of tetrazine-functionalized ruthenium(II) sonosensitizers have been designed and screened for establishing a bioorthogonal-activated in situ tumor vaccine via oncolytic pyroptosis induction. Based on nanodelivery-augmented bioorthogonal metabolic glycoengineering, the original tumor is selectively remolded to introduce artificial target bicycle [6.1.0] nonyne (BCN) into cell membrane. Through specific bioorthogonal ligation with intratumoral BCN receptors, sonosensitizers can realize precise membrane-anchoring and synchronous click-activation in desired tumor sites. Upon ultrasound (US) irradiation, the activated sonosensitizers can intensively disrupt the cell membrane with dual type I/II reactive oxygen species (ROS) generation for a high-efficiency sonodynamic therapy (SDT). More importantly, the severe membrane damage can eminently evoke oncolytic pyroptosis to maximize tumor immunogenicity and reverse immunosuppressive TME, ultimately eliciting powerful and durable systemic antitumor immunity. The US-triggered pyroptosis is certified to effectively inhibit the growths of primary and distant tumors, and suppress tumor metastasis and recurrence in "cold" tumor models. This bioorthogonal-driven tumor-specific pyroptosis induction strategy has great potential for the development of robust in situ tumor vaccines.

Malachite green: a long-buried water-soluble AIEgen with near-infrared fluorescence for living cell nucleus staining.

Fluorescent imaging probes are crucial for exploring nucleus-related cellular events in live cells. Ideal probes should be photostable, small-sized, highly contrasted, and low in background. Here, we discovered that malachite green is a water-soluble near-infrared luminogen with aggregation-induced emission properties. Importantly, it can be used for living cell nucleus staining in a wash-free manner.

Engineered Extracellular Vesicles Expressing Siglec-10 Camouflaged AIE Photosensitizer to Reprogram Macrophages to Active M1 Phenotype and Present Tumor-Associated Antigens for Photodynamic Immunotherapy.

Cancer immunotherapy has attracted considerable attention due to its advantages of persistence, targeting, and ability to kill tumor cells. However, the efficacy of tumor immunotherapy in practical applications is limited by tumor heterogeneity and complex tumor immunosuppressive microenvironments in which abundant of M2 macrophages and immune checkpoints (ICs) are present. Herein, two type-I aggregation-induced emission (AIE)-active photosensitizers with various reactive oxygen species (ROS)-generating efficiencies are designed and synthesized. Engineered extracellular vesicles (EVs) that express ICs Siglec-10 are first obtained from 4T1 tumor cells. The engineered EVs are then fused with the AIE photosensitizer-loaded lipidic nanosystem to form SEx@Fc-NPs. The ROS generated by the inner type-I AIE photosensitizer of the SEx@Fc-NPs through photodynamic therapy (PDT) can convert M2 macrophages into M1 macrophages to improve tumor immunosuppressive microenvironment. The outer EV-antigens that carry 4T1 tumor-associated antigens directly stimulate dendritic cells maturation to activate different types of tumor-specific T cells in overcoming tumor heterogeneity. In addition, blocking Siglec-10 reversed macrophage exhaustion for enhanced antitumor ability. This study presents that a combination of PDT, immune checkpoints, and EV-antigens can greatly improve the efficiency of tumor immunotherapy and is expected to serve as an emerging strategy to improve tumor immunosuppressive microenvironment and overcome immune escape.

Inducing tumor ferroptosis via a pH-responsive NIR-II photothermal agent initiating lysosomal dysfunction.

Ferroptosis is a unique programmed cell death process that was discovered a few years ago and plays an important role in tumor biology and treatment. However, it still remains a challenge to modulate tumor ferroptosis by spatiotemporally controlled cell-intrinsic Fenton chemistry. Herein, a pH activated photothermal sensitizer IR-PE has been designed and synthesized on the basis of cyanine bearing a diamine moiety, which is capable of triggering the lysosomal dysfunction-mediated Fenton pathway under the irradiation of near-infrared light to evoke ferroptosis, thereby improving antitumor efficacy and mitigating systemic side effects.

Biocompatible smart micro/nanorobots for active gastrointestinal tract drug delivery.

INTRODUCTION: Oral delivery is the most commonly used route of drug administration owing to good patient compliance. However, the gastrointestinal (GI) tract contains multiple physiological barriers that limit the absorption efficiency of conventional passive delivery systems resulting in a low drug concentration reaching the diseased sites. Micro/nanorobots can convert energy to self-propulsive force, providing a novel platform to actively overcome GI tract barriers for noninvasive drug delivery and treatment. AREAS COVERED: In this review, we first describe the microenvironments and barriers in the different compartments of the GI tract. Afterward, the applications of micro/nanorobots to overcome GI tract barriers for active drug delivery are highlighted and discussed. Finally, we summarize and discuss the challenges and future prospects of micro/nanorobots for further clinical applications. EXPERT OPINION: Micro/nanorobots with the ability to autonomously propel themselves and to load, transport, and release payloads on demand are ideal carriers for active oral drug delivery. Although there are many challenges to be addressed, micro/nanorobots have great potential to introduce a new era of drug delivery for precision therapy.

A Dual-Biomineralized Yeast Micro-/Nanorobot with Self-Driving Penetration for Gastritis Therapy and Motility Recovery.

Micro-/nanorobots have attracted great interest in the field of drug delivery and treatment, while preparations for biocompatible robots are extremely challenging. Here, a self-driving yeast micro-/nanorobot (Cur@CaY-robot) is designed via dual biomineralization and acid catalysis of calcium carbonate (CaCO3). Inner nano-CaCO3 inside yeast cells (CaY) is biomineralized through cell respiration and provides nanoscaffolds for highly encapsulating curcumin (Cur). Meanwhile, the CaCO3 crystals outside yeast cells (outer-CaCO3) through uniaxial growth offer an asymmetric power source for self-propelled motility. The Cur@CaY-robot displays an efficient motion in gastric acid, with the potential for deep penetration to the thick gastric mucus, which significantly improves the accumulation of drug agents in the stomach wall tissue for robust gastritis therapy. More importantly, Ca2+ cations released from the Cur@CaY-robot also synergistically repair the gastric motility of gastritis mice. Such yeast micro-/nanorobots exhibit desirable biocompatibility and biodegradability with a good loading capacity for drugs. This work provides an idea for the design of micro-/nanorobots through an environmentally friendly biosynthesis strategy for active drug delivery and precise therapy.

AIEgens/Mitochondria Nanohybrids as Bioactive Microwave Sensitizers for Non-Thermal Microwave Cancer Therapy.

Aggregation-induced emission luminogens (AIEgens) are widely used as photosensitizers for image-guided photodynamic therapy (PDT). Due to the limited penetration depth of light in biological tissues, the treatments of deep-seated tumors by visible-light-sensitized aggregation-induced emission (AIE) photosensitizers are severely hampered. Microwave dynamic therapy attracts much attention because microwave irradiation can penetrate very deep tissues and sensitize the photosensitizers to generate reactive oxygen species (ROS). In this work, a mitochondrial-targeting AIEgen (DCPy) is integrated with living mitochondria to form a bioactive AIE nanohybrid. This nanohybrid can not only generate ROS under microwave irradiation to induce apoptosis of deep-seated cancer cells but also reprogram the metabolism pathway of cancer cells through retrieving oxidative phosphorylation (OXPHOS) instead of glycolysis to enhance the efficiency of microwave dynamic therapy. This work demonstrates an effective strategy to integrate synthetic AIEgens and natural living organelles, which would inspire more researchers to develop advanced bioactive nanohybrids for cancer synergistic therapy.

Magnetic-Acoustic Sequentially Actuated CAR T Cell Microrobots for Precision Navigation and In Situ Antitumor Immunoactivation.

Despite its clinical success, chimeric antigen receptor T (CAR T)-cell immunotherapy remains limited in solid tumors, owing to the harsh physical barriers and immunosuppressive microenvironment. Here a CAR-T-cell-based live microrobot (M-CAR T) is created by decorating CAR T with immunomagnetic beads using click conjugation. M-CAR Ts are capable of magnetic-acoustic actuation for precision targeting and in situ activation of antitumor immune responses. Sequential actuation endows M-CAR Ts with magnetically actuated anti-flow and obstacle avoidance as well as tissue penetration driven by acoustic propulsion, enabling efficient migration and accumulation in artificial tumor models. In vivo, sequentially actuated M-CAR Ts achieves long-distance targeting and accumulate at the peritumoural area under programmable magnetic guidance, and subsequently acoustic tweezers actuate M-CAR Ts to migrate into deep tumor tissues, resulting in a 6.6-fold increase in accumulated exogenous CD8+ CAR T cells compared with that without actuation. Anti-CD3/CD28 immunomagnetic beads stimulate infiltrated CAR T proliferation and activation in situ, significantly enhancing their antitumor efficacy. Thus, this sequential-actuation-guided cell microrobot combines the merits of autonomous targeting and penetration of intelligent robots with in situ T-cell immunoactivation, and holds considerable promise for precision navigation and cancer immunotherapies.

Twin-bioengine self-adaptive micro/nanorobots using enzyme actuation and macrophage relay for gastrointestinal inflammation therapy.

A wide array of biocompatible micro/nanorobots are designed for targeted drug delivery and precision therapy largely depending on their self-adaptive ability overcoming complex barriers in vivo. Here, we report a twin-bioengine yeast micro/nanorobot (TBY-robot) with self-propelling and self-adaptive capabilities that can autonomously navigate to inflamed sites for gastrointestinal inflammation therapy via enzyme-macrophage switching (EMS). Asymmetrical TBY-robots effectively penetrated the mucus barrier and notably enhanced their intestinal retention using a dual enzyme-driven engine toward enteral glucose gradient. Thereafter, the TBY-robot was transferred to Peyer's patch, where the enzyme-driven engine switched in situ to macrophage bioengine and was subsequently relayed to inflamed sites along a chemokine gradient. Encouragingly, EMS-based delivery increased drug accumulation at the diseased site by approximately 1000-fold, markedly attenuating inflammation and ameliorating disease pathology in mouse models of colitis and gastric ulcers. These self-adaptive TBY-robots represent a safe and promising strategy for the precision treatment of gastrointestinal inflammation and other inflammatory diseases.

Cleavable collagenase-assistant nanosonosensitizer for tumor penetration and sonodynamic therapy.

Sonodynamic therapy (SDT), a combination of low-intensity ultrasound with a sonosensitizer, has been explored as a promising alternative for cancer therapy. However, condensed extracellular matrix (ECM) resulting in poor perfusion and extreme hypoxia in solid tumor potentially compromises effective SDT. Herein, we develop a novel cleavable collagenase-assistant and O2-supplied nanosonosensitizer (FePO2@HC), which is embedded through fusing collagenase (CLG) and human serum albumin (HSA), followed by encapsulating Ferric protoporphyrin (FeP) and dioxygen. As a smart carrier, HSA is stimuli-responsive and collapsed by reduced glutathione (GSH) overexpressed in tumor, resulting to the release of the components in FePO2@HC. The released CLG acting as an artificial scissor, degrades the collagen fibers in tumor, thus, breaking tumor tissue and enhancing FePO2 accumulation in tumor inner with higher than that without CLG. Simultaneously, oxygen molecules are released from FePO2 in hypoxic environment and alleviate the tumor hypoxia. As a sonosensitizer, FeP is subsequently irradiated by ultrosound wave (US) and activates surrounding dioxygen to generate amount of singlet oxygen (1O2). Contributed from the ECM-degradation, such SDT-based nanosystem with increased sonosensitizer permeability and oxygen content highly improved the tumor inhibition efficacy without toxic effects. This study presents a new paradigm for ECM depletion-based strategy of deep-seated penetration, and will expand the nanomedicine application of metalloporphyrin sonosensitizers in SDT.

Cell surface-nanoengineering for cancer targeting immunoregulation and precise immunotherapy.

Living cells have become ideal therapeutic agents for cancer treatment owing to their innate activities, such as efficient tumor targeting and delivery, easy engineering, immunomodulatory properties, and fewer adverse effects. However, cell agents are often fragile to rigorous tumor microenvironment (TME) and limited by inadequate therapeutic responses, leading to unwanted treatment efficacy. Cell nanomodification, particularly the cell surface-nanoengineering has emerged as reliable and efficient strategy that not only combines cell activity properties with nanomaterials but also endows them with extra novel functions, enabling to achieve remarkable treatment results. In this review, we systematically introduce two major strategies have been adopted to develop cell surface engineering with nanomaterials, mainly including living cell nano-backpacks and cell membrane-mimicking nanoparticles (NPs). Based on various functional NPs and cell types, we focus on reviewing the cell-surface nanoengineering for targeted drug delivery, immune microenvironment regulation, and precisely antitumor therapy. The advances and challenges of cell surface-nanoengineered antitumor agents for cancer therapy applications are further discussed in future clinical practice. This review provides an overview of the advances in cell surface-engineering for targeting immunoregulation and treatment and could contribute to the future of advanced cell-based antitumor therapeutic applications. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Cells at the Nanoscale.

Biomimetic Nanosonosensitizers Combined with Noninvasive Ultrasound Actuation to Reverse Drug Resistance and Sonodynamic-Enhanced Chemotherapy against Orthotopic Glioblastoma.

Glioblastoma (GBM) is the most devastating brain tumor and highly resistant to conventional chemotherapy. Herein, we introduce biomimetic nanosonosensitizer systems (MDNPs) combined with noninvasive ultrasound (US) actuation for orthotopic GBM-targeted delivery and sonodynamic-enhanced chemotherapy. MDNPs were fabricated with biodegradable and pH-sensitive polyglutamic acid (PGA) and the chemotherapeutic agent and sonosensitizer doxorubicin (DOX), camouflaged with human GBM U87 cell membranes. MDNPs presented homologous targeting accumulation and in vivo long-term circulation ability. They effectively passed through the blood-brain barrier (BBB) under US assistance and reached the orthotopic GBM site. MDNPs exhibited controllable US-elicited sonodynamic effect by generation of reactive oxygen species (ROS). ROS not only induced cancer cell apoptosis but also downregulated drug-resistance-related factors to disrupt chemoresistance and increase sensitivity to chemotherapy. The in vivo study of orthotopic GBM treatments further proved that MDNPs exhibited US-augmented synergistic antitumor efficacy and strongly prolonged the survival rate of mice. The use of low-dose DOX and the safety of US enabled repeated treatment (4 times) without obvious cardiotoxicity. This effective and safe US-enhanced chemotherapy strategy with the advantages of noninvasive brain delivery and high drug sensitivity holds great promise for deep-seated and drug-resistant tumors.

Aggregation-Induced-Emission Photosensitizer-Loaded Nano-Superartificial Dendritic Cells with Directly Presenting Tumor Antigens and Reversed Immunosuppression for Photodynamically Boosted Immunotherapy.

The success of tumor immunotherapy highlights the potential of harnessing immune system to fight cancer. Activating both native T cells and exhausted T cells is a critical step for generating effective antitumor immunity, which is determined based on the efficient presentation of tumor antigens and co-stimulatory signals by antigen-presenting cells, as well as immunosuppressive reversal. However, strategies for achieving an efficient antigen presentation process and improving the immunosuppressive microenvironment remain unresolved. Here, aggregation-induced-emission (AIE) photosensitizer-loaded nano-superartificial dendritic cells (saDC@Fs-NPs) are developed by coating superartificial dendritic cells membranes from genetically engineered 4T1 tumor cells onto nanoaggregates of AIE photosensitizers. The outer cell membranes of saDC@Fs-NPs are derived from recombinant lentivirus-infected 4T1 tumor cells in which peptide-major histocompatibility complex class I, CD86, and anti-LAG3 antibody are simultaneously anchored. These saDC@Fs-NPs could directly stimulate T-cell activation and reverse T-cell exhaustion for cancer immunotherapy. The inner AIE-active photosensitizers induce immunogenic cell death to activate dendritic cells and enhance T lymphocyte infiltration by photodynamic therapy, promoting the transformation of "cold tumors" into "hot tumors," which further boosts immunotherapy efficiency. This work presents a powerful photoactive and artificial antigen-presenting platform for activating both native T cells and exhausted T cells, as well as facilitating tumor photodynamic immunotherapy.

Biomimetic Active Materials Guided Immunogenic Cell Death for Enhanced Cancer Immunotherapy.

Despite immunotherapy emerging as a vital approach to improve cancer treatment, the activation of efficient immune responses is still hampered by immunosuppression, especially due to the low tumor immunogenicity. Immunogenic cell death (ICD) is a promising strategy to reshape the tumor microenvironment (TME) for achieving high immunogenicity. Various stimuli are able to effectively initiate their specific ICD by utilizing the corresponding ICD-inducer. However, the ICD-guided antitumor immune effects are usually impaired by various biological barriers and TME-associated immune resistance. Biomimetic active materials are being extensively explored as guided agents for ICD due to their unique advantages. In this review, two major strategies are systematically introduced that have been employed to exploit biomimetic active materials guided ICD for cancer immunotherapy, mainly including naive organism-derived nanoagents and engineered bioactive platforms. This review outlines the recent advances in the field at biomimetic active materials guided physiotherapy, chemotherapy, and biotherapy for ICD induction. The advances and challenges of biomimetic active materials guided ICD for cancer immunotherapy applications are further discussed in future clinical practice. This review provides an overview of the advances of biomimetic active materials for targeting immunoregulation and treatment and can contribute to the future of advanced antitumor combination therapy.

Rational Design, Synthesis of Fluorescence Probes for Quantitative Detection of Amyloid-ß in Alzheimer's Disease Based on Rhodamine-Metal Complex.

The efficient detection and monitoring of amyloid-ß plaques (Aß42) can greatly promote the diagnosis and therapy of Alzheimer's disease (AD). Fluorescence imaging is a promising method for this, but the accurate determination of Aß42 still remains a challenge. The development of a reliable fluorescent probe to detect Aß42 is essential. Herein, we report a rational design strategy for Aß42 fluorescence probes based on rhodamine-copper complexes, Rho1-Cu-Rho4-Cu, among them Rho4-Cu exhibits the best performance including high sensitivity (detection limit = 24 nM), high affinity (Kd = 23.4 nM), and high selectivity; hence, Rho4-Cu is selected for imaging Aß42 in AD mice, and the results showed that this probe can differentiate normal mice and AD mice effectively.