Safe, effective, and convenient administration of therapeutic nanomaterials is one of the greatest difficulties in nanomedicine. To tackle this challenge, a system which couples multi-enzyme mimicking CeO 2 nanoparticles with clinically approved montmorillonite (MMT) for inflammatory bowel disease (IBD) therapy is reported. CeO 2 exhibits superoxide dismutase- and catalase-like activities, and hydroxyl radical scavenging activity, making it more efficient at scavenging reactive oxygen species (ROS) than non-catalytic antioxidants while being more stable than free enzymes. In addition, negatively-charged MMT can be orally administered and specifically adsorbed onto positively-charged inflamed colon tissue via electrostatic interactions for targeted delivery. When the two are assembled together by in situ growth of CeO 2 onto MMT, the optimized CeO 2 @MMT(1:9) is stable in the stomach for oral delivery, targets the inflamed colon through electrostatic interactions, and reduces inflammation through ROS scavenging, all without any significant systemic exposure as demonstrated by the relief of murine IBD in vivo.
The exciting success of NBTXR3 in the clinic has triggered a tumult of activities in the design and development of hafnium-based nanoparticles. However, due to the concerns of nondegradation and limited functions, the biomedical applications of Hf-based nanoparticles mainly focus on tumors. Herein, tannic acid capped hafnium disulfide (HfS2@TA) nanosheets, a 2D atomic crystal of hafnium-based materials prepared by liquid-phase exfoliation, were explored as high-performance anti-inflammatory nanoagents for the targeted therapy of inflammatory bowel disease (IBD). Benefiting from the transformation of the S2–/S6+ valence state and huge specific surface area, the obtained HfS2@TA nanosheets were not only capable of effectively eliminating reactive oxygen species/reactive nitrogen species and downregulating pro-inflammatory factors but also could be excreted via kidney and hepatointestinal systems. Unexpectedly, HfS2@TA maintained excellent targeting capability to an inflamed colon even in the harsh digestive tract environment, mainly attributed to the electrostatic interactions between negatively charged tannic acid and positively charged inflamed epithelium. Encouragingly, upon oral or intravenous administration, HfS2@TA quickly inhibited inflammation and repaired the intestinal mucosa barrier in both dextran sodium sulfate and 2,4,6-trinitrobenzenesulfonic acid induced IBD models. This work demonstrated that ultrathin HfS2@TA atomic crystals with enhanced colon accumulation were promising for the targeted therapy of IBD.