Recent Advances in Interventional Fluorescence Imaging: Toward the Precise Visualization of Transarterial Mini-Invasive Delivery Systems

Emerging nanomedicines for macrophage-mediated cancer therapy

Tumor-associated macrophages (TAMs) contribute to tumor progression by promoting angiogenesis, remodeling the tumor extracellular matrix, inducing tumor invasion and metastasis, as well as immune evasion. Due to the high plasticity of TAMs, they can polarize into different phenotypes with distinct functions, which are primarily categorized as the pro-inflammatory, anti-tumor M1 type, and the anti-inflammatory, pro-tumor M2 type. Notably, anti-tumor macrophages not only directly phagocytize tumor cells, but also present tumor-specific antigens and activate adaptive immunity. Therefore, targeted regulation of TAMs to unleash their potential anti-tumor capabilities is crucial for improving the efficacy of cancer immunotherapy. Nanomedicine serves as a promising vehicle and can inherently interact with TAMs, hence, emerging as a new paradigm in cancer immunotherapy. Due to their controllable structures and properties, nanomedicines offer a plethora of advantages over conventional drugs, thus enhancing the balance between efficacy and toxicity. In this review, we provide an overview of the hallmarks of TAMs and discuss nanomedicines for targeting TAMs with a focus on inhibiting recruitment, depleting and reprogramming TAMs, enhancing phagocytosis, engineering macrophages, as well as targeting TAMs for tumor imaging. We also discuss the challenges and clinical potentials of nanomedicines for targeting TAMs, aiming to advance the exploitation of nanomedicine for cancer immunotherapy.

Recent Advances in Indocyanine Green-Based Probes for Second Near-Infrared Fluorescence Imaging and Therapy

Fluorescence imaging, a highly sensitive molecular imaging modality, is being increasingly integrated into clinical practice. Imaging within the second near-infrared biological window (NIR-II; 1,000 to 1,700 nm), also referred to as shortwave infrared, has received substantial attention because of its markedly reduced autofluorescence, deeper tissue penetration, and enhanced spatiotemporal resolution as compared to traditional near-infrared (NIR) imaging. Indocyanine green (ICG), a US Food and Drug Administration-approved NIR fluorophore, has long been used in clinical applications, including blood vessel angiography, vascular perfusion monitoring, and tumor detection. Recent advancements in NIR-II imaging technology have revitalized interest in ICG, revealing its extended tail fluorescence beyond 1,000 nm and reaffirming its potential as a clinically translatable NIR-II fluorophore for in vivo imaging and theranostic applications for diagnosing various diseases. This review emphasizes the notable advances in the use of ICG and its derivatives for NIR-II imaging and image-guided therapy from both fundamental and clinical perspectives. We also provide a concise conclusion and discuss the challenges and future opportunities with NIR-II imaging using clinically approved fluorophores.

Enhanced mitochondrial fluorescence imaging through confinement fluorescence effect within a rigid silicon suboxide network

Fluorescence imaging technology has emerged as a powerful tool for studying intricate mitochondrial morphology within living cells. However, the need for fluorophores with stable fluorescence intensity and low phototoxicity poses significant challenges, particularly for long-term live-cell mitochondrial monitoring. To address this, we introduce the confinement fluorescence effect (CFE) into the design of fluorophores. This strategy involves confining small-molecule fluorophores within a silicon suboxide network structure of nanoparticles (CEF-NPs), which restricts molecular rotation, resulting in the suppression of non-radiative transition and the isolation of encapsulated fluorophores from surrounding quenching factors. CFE-NPs (SY2@SiOx) exhibit exceptional properties, such as high fluorescence intensity (80-fold) and reduced phototoxicity (0.15-fold). Furthermore, the TPP + -functionalized CFE-NPs (SY2@SiOxTPP) demonstrated efficacy in mitochondrial imaging and mitochondrial dynamics monitoring. Biochemistry assays indicated that SY2@SiOxTPP exhibits significantly lower phototoxicity to mitochondrial functions compared to both small-molecule fluorophore and commercial Mito Tracker. This approach allows for the long-term dynamic monitoring of mitochondrial morphological changes through fluorescence imaging, without impairing mitochondrial functionality.

Molecular Engineering of Ultrabright Biomimetic NanoGhost for Site-Selective Tumor Imaging and Biodistribution

Optically active ultrabright imaging agents are shown to delineate tumor location with deep tissue visualization in pre noclinical tumor models. NanoGhosts (NGs) particles are reconstructed from the cell membrane and integrated with organic fluorophores to attain ultra-brightness for solid tumor imaging. Moreover, the integration of amphiphilic and lipophilic molecules reveals structural characteristics of NGs (≈70 nm), which also alter their brightness. Upon intravenous administration (10 mg kg-1 single dose), these ultrabright NGs (778 MESF) enable the high-resolution of tumor site and real-time tracking of vital organs with high-contrast fluorescence signals. Engineered biomimetic NGs demonstrates better resolution and tissue penetration as compared to the clinically approved indocyanine green (ICG). High precision in tumor detection (0.5 h) and strong tumor retention (24 h which is further up to 30th day) without affecting healthy tissues ensure the future scope of NGs in early-stage cancer imaging. These findings suggest that these NGs mimic the biological characteristics of native cells, enabling them to evade immune clearance and target the solid tumor naturally.

Three-in-One: Molecular Engineering of D-A-π-A Featured Type I and Type II Near-Infrared AIE Photosensitizers for Efficient Photodynamic Cancer Therapy and Bacteria Killing

Bacterial infections are closely correlated with the genesis and progression of cancer, and the elimination of cancer-related bacteria may improve the efficacy of cancer treatment. However, the combinatorial therapy that utilizes two or more chemodrugs will increase potential adverse effects. Image-guided photodynamic therapy is a highly precise and potential therapy to treat tumor and microbial infections. Herein, four donor-acceptor-π-bridge-acceptor (D-A-π-A) featured near-infrared (NIR) aggregation-induced emission luminogens (AIEgens) (TQTPy, TPQTPy, TQTC, and TPQTC) with type I and type II reaction oxygen species (ROS) generation capabilities are synthesized. Notably, TQTPy shows mitochondria targeted capacity, the best ROS production efficiency, long-term tumor retention capacity, and more importantly, the three-in-one fluorescence imaging guided therapy against both tumor and microbial infections. Both in vitro and in vivo results validate that TQTPy performs well in practical biomedical application in terms of NIR-fluorescence imaging-guided photodynamic cancer diagnosis and treatment. Moreover, the amphiphilic and positively charged TQTPy is able to specific and ultrafast discrimination and elimination of Gram-positive (G+) Staphylococcus aureus from Gram-negative (G-) Escherichia coli and normal cells. This investigation provides an instructive way for the construction of three-in-one treatment for image-guided photodynamic cancer therapy and bacteria elimination.

Supercritical Fluids: An Innovative Strategy for Drug Development

Nanotechnology plays a pivotal role in the biomedical field, especially in the synthesis and regulation of drug particle size. Reducing drug particles to the micron or nanometer scale can enhance bioavailability. Supercritical fluid technology, as a green drug development strategy, is expected to resolve the challenges of thermal degradation, uneven particle size, and organic solvent residue faced by traditional methods such as milling and crystallization. This paper provides an insight into the application of super-stable homogeneous intermix formulating technology (SHIFT) and super-table pure-nanomedicine formulation technology (SPFT) developed based on supercritical fluids for drug dispersion and micronization. These technologies significantly enhance the solubility and permeability of hydrophobic drugs by controlling the particle size and morphology, and the modified drugs show excellent therapeutic efficacy in the treatment of hepatocellular carcinoma, pathological scarring, and corneal neovascularization, and their performance and efficacy are highlighted when administered through multiple routes of administration. Overall, supercritical fluids have opened a green and efficient pathway for clinical drug development, which is expected to reduce side effects and enhance therapeutic efficacy.

Oral exosome-like nanovesicles from Phellinus linteus suppress metastatic hepatocellular carcinoma by reactive oxygen species generation and microbiota rebalancing

The biomedical application of nanotechnology in cancer treatment has demonstrated significant potential for improving treatment efficiencies and ameliorating adverse effects. However, the medical translation of nanotechnology-based nanomedicines faces challenges including hazardous environmental effects, difficulties in large-scale production, and possible excessive costs. In the present study, we extracted and purified natural exosome-like nanoparticles (ELNs) from Phellinus linteus. These nanoparticles (denoted as P-ELNs) had an average particle size of 154.1 nm, displayed a negative zeta potential of -31.3 mV, and maintained stability in the gastrointestinal tract. Furthermore, P-ELNs were found to contain a diverse array of functional components, including lipids and pharmacologically active small-molecule constituents. In vitro investigations suggested that they exhibited high internalization efficiency in liver tumor cells (Hepa 1-6) and exerted significant anti-proliferative, anti-migratory, and anti-invasive effects against Hepa 1-6 cells. Strikingly, the therapeutic outcomes of oral P-ELNs were confirmed in an animal model of metastatic hepatocellular carcinoma by amplifying reactive oxygen species (ROS) and rebalancing the gut microbiome. These findings demonstrate the potential of P-ELNs as a promising oral therapeutic platform for liver cancer treatment.