In Vivo Aggregation of Clearable Bimetallic Nanoparticles with Interlocked Surface Motifs for Cancer Therapeutics Amplification

Organotropic Engineering of Luminescent Gold Nanoclusters for In Vivo Imaging of Lung Orthotopic Tumors

Gold nanoclusters (AuNCs) are emerging as promising functional probes for bioapplications. However, because of rapid renal clearance, it is a challenge to tailor their biofate and improve their disease-targeting ability in vivo. Herein, we report an efficient strategy to tailor their organotropic actions by rationally designing AuNC assemblies. The nanocluster assembly is established based on the moderate electrostatic interaction or strong coordination between AuNCs, enabled by solely chitosan (CS) or the coadded chelating metal ions (e.g., Gd3+). We show that AuNCs-CS is rapidly excreted into urine, while further coordination of Gd3+ confers assemblies with liver and lung accumulation capabilities, dependent on Gd3+ contents. The organotropic actions are unraveled to result from their tunable stability in vivo and binding capability to cells/proteins. We also demonstrate that lung-targeting assemblies can enable specific NIR-II luminescence imaging of lung orthotopic tumors, which cannot be realized by employing discrete AuNCs. We anticipate that these findings will offer insights into the design principles of metal nanocluster probes and related bioapplications.

Induction of Non-Canonical Ferroptosis by Targeting Clusters Suppresses Glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive brain tumor. There is a pressing need to develop novel treatment strategies due to the poor targeting effect of current therapeutics. Here, a gold cluster coated with optimized GBM-targeting peptide is engineered, namely NA. NA can efficiently target GBM both in vitro and in vivo. Interestingly, the uptake of NA significantly sensitizes GBM cells to ferroptosis, a form of programmed cell death that can bypass the tumor resistance to apoptosis. This effect is exerted through regulating the HO-1-dependent iron ion metabolism, which is the non-canonical pathway of ferroptosis. The combined treatment of a ferroptosis inducer and NA profoundly inhibited tumor growth in both the GBM spheroid model and a syngeneic mouse model with enhanced ferroptosis levels and excellent biosafety. Importantly, the infiltration of tumoricidal lymphocytes is also significantly increased within tumor. Therefore, NA presents a potential novel nanomaterial-based strategy for GBM treatment.

Intrarenal pH-Responsive Self-Assembly of Luminescent Gold Nanoparticles for Diagnosis of Early Kidney Injury

Metabolic acidosis-induced kidney injury (MAKI) is asymptomatic and lack of clinical biomarkers in early stage, but rapidly progresses to severe renal fibrosis and ultimately results in end-stage kidney failure. Therefore, developing rapid and noninvasive strategies direct responsive to renal tubular acidic microenvironment rather than delayed biomarkers are essential for timely renoprotective interventions. Herein, we develop pH-responsive luminescent gold nanoparticles (p-AuNPs) in the second near-infrared emission co-coated with 2,3-dimethylaleic anhydride conjugated β-mercaptoethylamine and cationic 2-diethylaminoethanethiol hydrochloride, which showed sensitive pH-induced charge reversal and intrarenal self-assembly for highly sensitive and long-time (~24 h) imaging of different stages of MAKI. By integrating advantages of pH-induced intrarenal self-assembly and enhanced interactions between pH-triggered positively charged p-AuNPs and renal tubular cells, the early- and late-stage MAKI could be differentiated rapidly within 10 min post-injection (p.i.) with contrast index (CI) of 3.5 and 4.3, respectively. The corresponding maximum CI could reach 5.1 and 9.2 at 12 h p.i., respectively. Furthermore, p-AuNPs were demonstrated to effectively real-time monitor progressive recovery of kidney injury in MAKI mice after therapy, and also exhibit outstanding capabilities for drug screening. This pH-responsive strategy showed great promise for feedback on kidney dysfunction progression, opening new possibilities for early-stage diagnosis of pH-related diseases.

Self-Assembly of 2D Polyphthalocyanine in Lysosome Enables Multienzyme Activity Enhancement to Induce Tumor Ferroptosis

Nanozymes show great potential in facilitating tumor ferroptosis by upregulation of reactive oxygen species (ROS) and downregulation of glutathione (GSH). However, mild acidity (pH 6.5-6.9) of tumor microenvironment severely restricts the activity of nanozymes. Although lysosomes as acidic organelles (pH = 3.5-5.5) are hopeful for improving enzyme-like activity, most reported nanozymes are not capable of effectively accumulating in the lysosomes. Herein, an acid-responsive self-assembly strategy based on iron phthalocyanine-rich covalent organic framework nanosheets (COFFePc NSs) is developed, which enables lysosomal targeting aggregation of COFFePc NSs due to the existence of abundant negative hydroxyl groups and rigid structure. Meanwhile, COFFePc NSs display exceptional multienzyme-mimic performance at lower pH to efficiently generate ROS to cause lysosome damage and apoptosis by synergistic photothermal effect. Subsequently, the released COFFePc with GSH oxidase-mimicking activity can consume GSH to promote ferroptosis. This is the first report of a 2D COF using its own properties to achieve lysosomal self-assembly. Overall, the work provides a new paradigm for the development of lysosome-targeted nanosystems.

Unveiling the Impact of Light-Induced Acceptor-Generated ROS on Device Stability in Organic Photovoltaics

The intrinsic stability of the acceptor is a crucial component of the photovoltaic device stability. In this study, we investigated the efficiency and stability of the nonfused-ring acceptors LC8 and BC8 under indoor light conditions. Interestingly, we found that devices based on BC8 with terminal side chains exhibited a higher indoor efficiency and stability. Through accelerated aging experiments, we discovered that the acceptors generate singlet oxygen under light exposure with BC8 demonstrating lower levels of ROS compared to LC8. We attribute this difference to the modulation of the acceptor aggregation orientation. Furthermore, the generated reactive oxygen species (ROS) further deteriorate the acceptor structure, and this phenomenon is also observed in high-efficiency acceptor structures, such as Y6. Our research reveals important mechanisms of acceptor photo-oxidation processes, providing a theoretical basis for enhancing the intrinsic stability of acceptors.