口腔健康是全身健康的重要组成部分。基质金属蛋白酶-2 (MMP-2) 是疾病的潜在生物标志物。在体内和体外准确检测 MMP-2 的能力对于口腔疾病的早期诊断、预后以及治疗评估非常重要。本研究将含有MMP-2特异性肽底物 (PLGVR) 的 Cy3 多肽修饰到二氧化硅包覆上转换荧光纳米颗粒上，构建出基于荧光共振能量转移（FRET）的比率荧光纳米平台（UCNPs @ SiO2 @ Cy3-pep）。UCNPs @ SiO2 的绿色上转换荧光由于 Cy3 被猝灭，而其红色上转换荧光则不受干扰。 当 MMP-2 在 PLGVR 肽段上切割 Cy3 时，它从 UCNPs @ SiO2 的表面分离出来，从而恢复绿色荧光。基于这个原理，我们将 UCNPs @ SiO2 @ Cy3-pep 应用于检测不同口腔疾病样本和模型中 MMP-2 的活性。我们发现，口腔癌患者的唾液 MMP-2 水平比健康个体高10倍。此外，牙周炎和严重龋齿患者的 MMP-2 水平也与健康患者相比有所增加。最后，在 vitro 和 in vivo 成像实验中，我们发现该纳米平台检测 MMP-2 水平十分有效。综上所述，该研发的纳米平台可以成为 MMP-2 相关疾病的医学诊断理想工具。Copyright © 2023 Elsevier B.V. All rights reserved.

Oral health is an essential part of overall health. Matrix metalloproteinase-2 (MMP-2) is a potential biomarker for diseases. The ability to accurately detect MMP-2 in vivo and in vitro is of great importance for the early diagnosis and prognosis, as well as the treatment evaluation, of oral diseases. In this study, cyanine 3 (Cy3) polypeptide containing the specific peptide substrate (PLGVR) of MMP-2 was modified onto SiO2-coated upconversion nanoparticles to fabricate a fluorescence resonance energy transfer (FRET)-based ratiometric fluorescent nanoplatform (UCNPs@SiO2@Cy3-pep). The green upconversion luminescence of UCNPs@SiO2 is quenched by Cy3, while its red upconversion luminescence is undisturbed. After Cy3 is cleaved at the PLGVR peptide by MMP-2, it is detached from the surface of UCNPs@SiO2, resulting in the recovery of green luminescence. Based on this principle, we applied UCNPs@SiO2@Cy3-pep to detect MMP-2 activity in different oral disease samples and models. We found that the level of MMP-2 in saliva of patients with oral cancer was 10 times higher than that of healthy individuals. In addition, the MMP-2 level in patients with periodontitis and severe dental caries also increased to varying degrees compared with that in healthy patients. Finally, in vitro and in vivo imaging experiments revealed that the nanoplatform was effective in monitoring MMP-2 level. Together, the developed nanoplatform can be an ideal tool for medical diagnosis of MMP-2-related diseases.Copyright © 2023 Elsevier B.V. All rights reserved.