Lanthanum-loaded ZIF nanomaterials for caries prevention

Abstract

Dental caries represents one of the most widespread oral health challenges worldwide, impacting people of every age demographic. Traditional anticaries strategies primarily rely on fluoride, yet its chronic overuse may lead to health issues such as dental fluorosis. Lanthanum (La), a rare earth element, has emerged as a promising fluoride alternative due to its low toxicity and strong anticaries activity. However, studies have shown that the direct use of free lanthanum under physiological conditions may cause cellular structural damage, dose-dependent hemolytic reactions, and even liver and kidney fibrosis, highlighting the urgent need to optimize its delivery method. In this study, zeolitic imidazolate framework nanoparticles (La@ZIF) were used to encapsulate lanthanum, enabling its controlled and sustained release, thereby proposing a novel fluoride-free anticaries strategy. Three La@ZIF nanoparticles with varying La incorporation levels (20%, 40%, and 60%) were synthesized via a one-pot method and systematically characterized. Results demonstrated their excellent degradation performance and acid-neutralizing capacity under acidic conditions. In vitro experiments confirmed the favorable biocompatibility of La@ZIF and its ability to effectively promote enamel remineralization and restore surface hardness, achieving comparable efficacy to traditional fluoride treatments. In vivo studies further validated the remineralization potential of La@ZIF in a rat model, with no adverse effects observed on major organs. La@ZIF nanoparticles exhibit remarkable anticaries performance and biosafety, offering a new direction for developing fluoride-free anticaries materials.