Acid and Hypoxia Tandem-Activatable Deep Near-Infrared Nanoprobe for Two-Step Signal Amplification and Early Detection of Cancer

A cascaded amplification carrier-free nanoplatform for synergistic photothermal/ferroptosis therapy via dual antioxidant pathway disruption in cervical cancer

Cellular defense mechanisms against ferroptosis are primarily mediated by antiferroptotic regulators, particularly glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1). Notably, singlet oxygen (1O2) generated through photoactivation of organic small-molecule photosensitizers (PSs) has been demonstrated to deplete both glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH). This dual depletion mechanism effectively disrupts the GSH/GPX4 redox axis and the NADPH/FSP1/ubiquinone (CoQ) antioxidant system, thereby potentiating ferroptosis. In this study, we engineered a tumor-targeting amphiphilic iridium-based photosensitizer nanoplatform (Ir-TCF3P-FA NPs) for synergistic photothermal-ferroptosis therapy. Specifically, GSH depletion and NADPH oxidation by 1O2 produced via Ir-TCF3P-FA NPs at 450 nm can suppress the expression of GPX4 and FSP1, amplifying ferroptosis. Additionally, TCF3P exhibited high photothermal conversion efficiency at 808 nm, which not only can enhance photothermal therapy (PTT) efficacy but also facilitated 1O2 generation. The Ir-TCF3P-FA NPs enable effective tumor-targeted delivery and fluorescence/photoacoustic imaging for in vivo distribution tracking. In vivo studies revealed that dual-laser irradiation of Ir-TCF3P-FA NPs provided potent therapeutic efficacy, significantly inhibiting human cervical cancer progression in murine models. This cascaded amplification carrier-free nanoplatform holds promise for clinical multimodal treatment of cervical cancer.

Stimuli-Responsive Polymeric Nanoprobes for Bioimaging of Cancer Metastasis

Stimuli-responsive polymeric nanoprobes as a type of nanoscale probe can respond to the tumor microenvironment via specific stimuli inside tumors, such as pH, hypoxia, glutathione (GSH), enzymes, aberrant receptors, and high ATP concentration. The ingenious design of the nanoprobes can improve the specificity and sensitivity to distinguish the slight differences between normal tissues and tumors. Thus, the tiny tumor metastasis can be detected by bioimaging of the stimuli-responsive polymeric nanoprobes. This review summarizes the progress and applications of polymeric nanoprobes in the bioimaging of tumor metastasis. The design strategies for the nanoprobes targeting tumor tissues are discussed according to the stimulus types, including tumor pH, hypoxia, glutathione, enzymes, aberrant receptor, and ATP. Moreover, the challenges currently faced in this field are also discussed. This review will provide valuable insights for the design and optimization of stimuli-responsive polymeric nanoprobes to accelerate the development of bioimaging for tumor metastasis and promote the clinical translation.

Tandem Dual-Ratiometric SERS Probe Enables Raman Imaging of Neurological pH Fluctuations in Epilepsy

An imbalance of brain pH is closely associated with biochemical reactions, ion regulation, and electrical activity, serving as a hallmark for various neurological disorders. High-resolution imaging of pH fluctuations in brain disease is crucial for understanding pathological processes. However, current pH probes are inadequate for this purpose due to poor blood-brain barrier (BBB) penetration or insufficient specificity. Herein, we reported a tandem dual-ratiometric surface-enhanced Raman scattering (SERS) probe, RHP@AuS, capable of crossing the BBB to address these challenges. RHP@AuS leveraged dendrimers for the facile one-step synthesis of SERS probes, significantly enhancing signal intensity and reproducibility. RHP@AuS can be sequentially activated by neuroinflammation-associated H2O2 and pH, exhibiting highly selective ratiometric responses to pH fluctuations in brain disease. Dynamic SERS imaging revealed that during neuronal epileptic activity, inflammation increased and local pH dropped sharply to around 6.6. Building on these findings, a drug combination with dual neuroinflammation-mitigating and pH-regulating properties was developed, effectively alleviating epilepsy in mouse models. This study opens new avenues for developing imaging probes for the brain and deepens our understanding of the roles of pH in neurological disorders.

Energy-Confinement 3D Flower-Shaped Cages for AI-Driven Decoding of Metabolic Fingerprints in Cardiovascular Disease Diagnosis

Rapid and accurate detection plays a critical role in improving the survival and prognosis of patients with cardiovascular disease, but traditional detection methods are far from ideal for those with suspected conditions. Metabolite analysis based on nanomatrix-assisted laser desorption/ionization mass spectrometry (NMALDI-MS) is considered to be a promising technique for disease diagnosis. However, the performance of core nanomatrixes has limited its clinical application. In this study, we constructed 3D flower-shaped cages based on controllable structured metal-organic frameworks and iron oxide nanoparticles with low thermal conductivity and significant photothermal effects. The elongation of the incident light path through multilayer reflection significantly enhances the effective light absorption area of the nanomatrixes. Concurrently, the alternating layered structure confines the thermal energy, reducing thermal losses. Moreover, the 3D structure increases affinity sites, expanding the detection coverage. This approach effectively enhances the laser ionization and thermal desorption efficiency during the LDI process. We applied this technology to analyze the serum metabolomes of patients with myocardial infarction, heart failure, and heart failure combined with myocardial infarction, achieving cost-effective, high-throughput, highly accurate, and user-friendly detection of cardiovascular diseases. Subsequently, deep analysis of detected serum fingerprints via artificial intelligence models screens potential metabolic biomarkers, providing a new paradigm for the accurate diagnosis of cardiovascular diseases.

Renal Clearable Chiral Manganese Oxide Supraparticles for In Vivo Detection of Metalloproteinase-9 in Early Cancer Diagnosis

In this study, polypeptide TGGGPLGVARGKGGC-induced chiral manganese dioxide supraparticles (MnO2 SPs) are prepared for sensitive quantification of matrix metalloproteinase-9 (MMP-9) in vitro and in vivo. The results show that L-type manganese dioxide supraparticles (L-MnO2 SPs) exhibited twice the affinity for the cancer cell membrane receptor CD47 (cluster of differentiation, integrin-associated protein) than D-type manganese dioxide supraparticles (D-MnO2 SPs) to accumulate at the tumor site after surface modification of the internalizing arginine-glycine-aspartic acid (iRGD) ligand, specifically reacting with the MMP-9, disassembling into ultrasmall nanoparticles (NPs), and efficiently underwent renal clearance. Furthermore, L-MnO2 facilitates the quantification of MMP-9 in mouse tumor xenografts, as demonstrated by circular dichroism (CD) and magnetic resonance imaging (MRI) within 2 h. A strong linear relationship is observed between MMP-9 concentration and both CD and MRI intensity, ranging from 0.01 to 10 ng mL-1. The corresponding limits of detection (LOD) are 0.0054 ng mL-1 for CD and 0.0062 ng mL-1 for MRI, respectively. hese SPs provide a new approach for exploring chiral advanced biosensors for early diagnosis of cancer.

Engineered hypoxia-responsive albumin nanoparticles mediating mitophagy regulation for cancer therapy

Hypoxic tumors present a significant challenge in cancer therapy due to their ability to adaptation in low-oxygen environments, which supports tumor survival and resistance to treatment. Enhanced mitophagy, the selective degradation of mitochondria by autophagy, is a crucial mechanism that helps sustain cellular homeostasis in hypoxic tumors. In this study, we develop an azocalix[4]arene-modified supramolecular albumin nanoparticle, that co-delivers hydroxychloroquine and a mitochondria-targeting photosensitizer, designed to induce cascaded oxidative stress by regulating mitophagy for the treatment of hypoxic tumors. These nanoparticles are hypoxia-responsive and release loaded guest molecules in hypoxic tumor cells. The released hydroxychloroquine disrupts the mitophagy process, thereby increasing oxidative stress and further weakening the tumor cells. Additionally, upon laser irradiation, the photosensitizer generates reactive oxygen species independent of oxygen, inducing mitochondria damage and mitophagy activation. The dual action of simultaneous spatiotemporal mitophagy activation and mitophagy flux blockade results in enhanced autophagic and oxidative stress, ultimately driving tumor cell death. Our work highlights the effectiveness of hydroxychloroquine-mediated mitophagy blockade combined with mitochondria-targeted photosensitizer for cascade-amplified oxidative stress against hypoxic tumors.

Assessing Wound Healing in Vivo Using a Dual-Function Phosphorescent Probe Sensitive to Tissue Oxygenation and Regenerating Collagen

Levels of tissue oxygenation and collagen regeneration are critical indicators in the early evaluation of wound healing. Traditionally, these factors have been assessed using separate instruments and different methodologies. Here, we adopt the spatially averaged phosphorescence lifetime approach using ReI-diimine complexes (ReI-probe) to enable simultaneous quantification of these two critical factors in healing wounds. The topically applied, biocompatible ReI-probe penetrates wound tissue effectively and selectively binds to collagen fibers. During collagen regeneration, the phosphorescence lifetimes of the collagen-bound probe significantly extend from an initial range of 4.5-6.5 μs on day 0 to 5.5-8.5 μs by day 7. Concurrently, unbound probes in the tissue interstitial spaces exhibit a phosphorescence lifetime of 4.5-5.2 μs, revealing the oxygenation states. Using phosphorescence lifetime imaging microscopy (PLIM) and a frequency domain phosphorescence lifetime measurement (FD-PLM) system, we validated the dual-functionality of this ReI-probe in differentiating healing stages in chronic wounds. With its noninvasive, quantitative measurement capabilities for cutaneous wounds, this ReI-probe-based approach offers promising potential for early wound healing diagnosis.

NIR-II Ratiometric Optical Theranostic Capsule for In Situ Diagnosis and Precise Therapy of Intestinal Inflammation

Capsules were widely used in clinical settings for the oral delivery of various drugs, although it remains challenging to trace real-time drug release behavior and adjust dosages based on the therapeutic effect. To address these issues, we developed theranostic capsules that loaded two kinds of fluorescence nanoparticles, H2O2-responsive Janus Ag/Ag2S nanoparticles (Ag/Ag2S JNPs) and the downconversion nanoparticles (DCNPs), and the dexamethasone (Dex) drug. The Ag/Ag2S JNPs exhibit a highly sensitive fluorescence (FL) signal at 1250 nm in response to H2O2, while the FL signal from the DCNPs at 1550 nm remains stable under physiological conditions. The ratio of these two FL signals formed the ratiometric FL signal, which shows correlation with the H2O2 concentration with a detection limit of 1.7 μM. Moreover, the capsules can be precisely delivered into the intestine, where they release the JNPs and DCNPs simultaneously. The H2O2-triggered ratiometric FL signals and images can diagnose inflammation and indicate its location. Meanwhile, the encapsulated Dex is released in the disease region, with ratiometric imaging allowing for real-time tracking of therapeutic efficacy and providing guidance for ongoing treatment. The theranostic capsule system provides an approach for quantitative detection of disease biomarkers and further localized release of therapeutics, thereby avoiding overdose and reducing side effects.

Comprehensive review of drug resistance in mammalian cancer stem cells: implications for cancer therapy

Cancer remains a significant global challenge, and despite the numerous strategies developed to advance cancer therapy, an effective cure for metastatic cancer remains elusive. A major hurdle in treatment success is the ability of cancer cells, particularly cancer stem cells (CSCs), to resist therapy. These CSCs possess unique abilities, including self-renewal, differentiation, and repair, which drive tumor progression and chemotherapy resistance. The resilience of CSCs is linked to certain signaling pathways. Tumors with pathway-dependent CSCs often develop genetic resistance, whereas those with pathway-independent CSCs undergo epigenetic changes that affect gene regulation. CSCs can evade cytotoxic drugs, radiation, and apoptosis by increasing drug efflux transporter activity and activating survival mechanisms. Future research should prioritize the identification of new biomarkers and signaling molecules to better understand drug resistance. The use of cutting-edge approaches, such as bioinformatics, genomics, proteomics, and nanotechnology, offers potential solutions to this challenge. Key strategies include developing targeted therapies, employing nanocarriers for precise drug delivery, and focusing on CSC-targeted pathways such as the Wnt, Notch, and Hedgehog pathways. Additionally, investigating multitarget inhibitors, immunotherapy, and nanodrug delivery systems is critical for overcoming drug resistance in cancer cells.

Shining New Light on Biological Systems: Luminescent Transition Metal Complexes for Bioimaging and Biosensing Applications

Luminescence imaging is a powerful and versatile technique for investigating cell physiology and pathology in living systems, making significant contributions to life science research and clinical diagnosis. In recent years, luminescent transition metal complexes have gained significant attention for diagnostic and therapeutic applications due to their unique photophysical and photochemical properties. In this Review, we provide a comprehensive overview of the recent development of luminescent transition metal complexes for bioimaging and biosensing applications, with a focus on transition metal centers with a d6, d8, and d10 electronic configuration. We elucidate the structure-property relationships of luminescent transition metal complexes, exploring how their structural characteristics can be manipulated to control their biological behavior such as cellular uptake, localization, biocompatibility, pharmacokinetics, and biodistribution. Furthermore, we introduce the various design strategies that leverage the interesting photophysical properties of luminescent transition metal complexes for a wide variety of biological applications, including autofluorescence-free imaging, multimodal imaging, organelle imaging, biological sensing, microenvironment monitoring, bioorthogonal labeling, bacterial imaging, and cell viability assessment. Finally, we provide insights into the challenges and perspectives of luminescent transition metal complexes for bioimaging and biosensing applications, as well as their use in disease diagnosis and treatment evaluation.

Multidimensional Interactive Cascading Nanochips for Detection of Multiple Liver Diseases via Precise Metabolite Profiling

It is challenging to detect and differentiate multiple diseases with high complexity/similarity from the same organ. Metabolic analysis based on nanomatrix-assisted laser desorption/ionization mass spectrometry (NMALDI-MS) is a promising platform for disease diagnosis, while the enhanced property of its core nanomatrix materials has plenty of room for improvement. Herein, a multidimensional interactive cascade nanochip composed of iron oxide nanoparticles (FeNPs)/MXene/gold nanoparticles (AuNPs), IMG, is reported for serum metabolic profiling to achieve high-throughput detection of multiple liver diseases. MXene serves as a multi-binding site and an electron-hole source for ionization during NMALDI-MS analysis. Introduction of AuNPs with surface plasmon resonance (SPR) properties facilitates surface charge accumulation and rapid energy conversion. FeNPs are integrated into the MXene/Au nanocomposite to sharply reduce the thermal conductivity of the nanochip with negligible heat loss for strong thermally-driven desorption, and construct a multi-interaction proton transport pathway with MXene and AuNPs for strong ionization. Analysis of these enhanced serum fingerprint signals detected from the IMG nanochip through a neural network model results in differentiation of multiple liver diseases via a single pass and revelation of potential metabolic biomarkers. The promising method can rapidly and accurately screen various liver diseases, thus allowing timely treatment of liver diseases.

A Journey of Challenges and Victories: A Bibliometric Worldview of Nanomedicine since the 21st Century

Nanotechnology profoundly affects the advancement of medicine. Limitations in diagnosing and treating cancer and chronic diseases promote the growth of nanomedicine. However, there are very few analytical and descriptive studies regarding the trajectory of nanomedicine, key research powers, present research landscape, focal investigative points, and future outlooks. Herein, articles and reviews published in the Science Citation Index Expanded of Web of Science Core Collection from first January 2000 to 18th July 2023 are analyzed. Herein, a bibliometric visualization of publication trends, countries/regions, institutions, journals, research categories, themes, references, and keywords is produced and elaborated. Nanomedicine-related academic output is increasing since the COVID-19 pandemic, solidifying the uneven global distribution of research performance. While China leads in terms of publication quantity and has numerous highly productive institutions, the USA has advantages in academic impact, commercialization, and industrial value. Nanomedicine integrates with other disciplines, establishing interdisciplinary platforms, in which drug delivery and nanoparticles remain focal points. Current research focuses on integrating nanomedicine and cell ferroptosis induction in cancer immunotherapy. The keyword "burst testing" identifies promising research directions, including immunogenic cell death, chemodynamic therapy, tumor microenvironment, immunotherapy, and extracellular vesicles. The prospects, major challenges, and barriers to addressing these directions are discussed.

Sulfonated Perylene as Three-in-One STING Agonist for Cancer Chemo-Immunotherapy

Activation of stimulator of interferon genes (STING) by cyclic dinucleotides (CDNs) has been considered as a powerful immunotherapy strategy. While promising, the clinical translation of CDNs is still overwhelmed by its limited biostability and the resulting systemic immunotoxicity. Being differentiating from current application of exogenous CDNs to address these challenges, we herein developed one perylene STING agonist PDIC-NS, which not only promotes the production of endogenous CDNs but also inhibits its hydrolysis. More significantly, PDIC-NS can well reach lung-selective enrichment, and thus mitigates the systemic immunotoxicity upon intravenous administration. As a result, PDIC-NS had realized remarkable in vivo antitumor activity, and backward verified on STING knock out mice. Overall, this study states that PDIC-NS can function as three-in-one small-molecule STING agonist characterized by promoting the content and biostability of endogenous CDNs as well as possessing good tissue specificity, and hence presents an innovative strategy and platform for tumor chemo-immunotherapy.

Oxygen and pH responsive theragnostic liposomes for early-stage diagnosis and photothermal therapy of solid tumours

The development of cancer treatment is of great importance, especially in the early stage. In this work, we synthesized a pH-sensitive amphiphilic ruthenium complex containing two alkyl chains and two PEG chains, which was utilized as an oxygen sensitive fluorescent probe for co-assembly with lipids to harvest a liposomal delivery system (RuPC) for the encapsulation of a photothermal agent indocyanine green (ICG). The resultant ICG encapsulated liposome (RuPC@ICG) enabled the delivery of ICG into cells via a membrane fusion pathway, by which the ruthenium complex was localized in the cell membrane for better detection of the extracellular oxygen concentration. Such characteristics allowed ratiometric imaging to distinguish the tumour location from normal tissues just 3 days after cancer cells were implanted, by monitoring the hypoxia condition and tracing the metabolism. Moreover, the pH sensitivity of the liposomes favoured cell uptake, and improved the anti-tumour efficiency of the formulation in vivo under NIR irradiation. Assuming liposomal systems have fewer safety issues, our work not only provides a facile method for the construction of a theragnostic system by combining phototherapy with photoluminescence imaging, but hopefully paves the way for clinical translation from bench to bedside.

A Rare-Earth Near-Infrared Nanoprobe for the Identification of Small Cell Lung Cancer

Background

Small cell lung cancer (SCLC) is a common subtype of lung cancer, and there is currently no established method for the early identification of SCLC. We prepared a novel rare-earth near-infrared (NIR) downconversion nanoprobe to identify SCLC cells.

Methods

The shell precursors Gd-OA and Na-TFA-OA were prepared, and the NaYF4:Nd@NaGdF4-ProGRP antibody probe was obtained after synthesizing downconversion fluorescent nanocrystals. The probe was used for NIR identification of cancer cells and subcutaneous tumors in nude mice. The biotoxicity of the probe to SCLC cells and nude mice was studied.

Results

The NaYF4:Nd@NaGdF4-ProGRP antibody probe was successfully prepared, with a size of 44 nm, an NIR emission peak at approximately 1060 nm, and a concentration of 40 μmol/mL. The probe could achieve accurate NIR identification of SCLC cells and subcutaneous tumors in nude mice. Optimal images of the subcutaneous tumor model were obtained approximately 10 minutes after probe injection. There was no significant change in the hematology indices, respiratory rate, or heart rate of nude mice after the probe was injected (all P > 0.05).

Conclusion

We have successfully prepared a low-toxicity probe that can identify SCLC cells, which may be useful for the early detection of SCLC. And conduct theoretical exploration for non-invasive identification and identification of some early metastatic lesions without pathological sampling in the future.