# The Value of the Near‐Infrared Fluorescent Probe ErNP@SiO2‐ICG in the Diagnosis of Malignant Pleural Effusion

## TL;DR

A new near-infrared fluorescent probe called ErNP@SiO2-ICG shows promise in accurately diagnosing malignant pleural effusion, a serious condition linked to advanced cancers.

## Contribution

The study introduces and evaluates a novel rare earth nano-probe for diagnosing malignant pleural effusion with high accuracy.

## Key findings

- ErNP@SiO2-ICG demonstrated a high area under the ROC curve (0.814) for fluorescence imaging in detecting malignant pleural effusion.
- The probe showed better diagnostic accuracy compared to traditional cytological assessments of pleural effusions.
- The probe's fluorescence imaging results correlated well with pathological findings (Kappa = 0.629).

## Abstract

Malignant pleural effusions (MPEs) present a significant clinical challenge and are associated with a poor prognosis, frequently observed in patients with advanced malignancies. Conventional diagnostic techniques for identifying MPEs exhibit limitations in both accuracy and sensitivity. To differentiate between benign and MPEs, the clinical applicability of the ErNP@SiO2‐ICG rare earth nano–nano near‐infrared (NIR) fluorescence probe was investigated.

Through solution chemistry processes, vacuum treatment with heat, and the synthesis of a core–shell design, an exceptional rare earth nano NIR fluorescent probe was developed in this study, which showed the capacity to target tumors precisely. After that, a prospective research was conducted with a cohort of 90 patients; 20 of them were excluded because of unclear diagnoses. Every participant had a thoracoscopic biopsy for histological analysis, a cytological assessment of pleural effusions, and an evaluation of the recently developed dyes. R programming, GraphPad Prism, and Microsoft Excel were used when carrying out statistical inspection of the obtained data.

ErNP@SiO2‐ICG particles experienced a size of 176.1 ± 0.2 nm. Their emission peak was located at 550 nm in relation to their fluorescence spectra, and their scanning electron microscopy image demonstrated uniform particle size and distribution with NIR fluorescence characteristics. The optimum time and concentration for color development were 2 μL and 1 h, respectively. The fluorescence imaging and cytological investigation of pleural effusions differed significantly (p < 0.001) in 35 scenarios of MPEs, 35 cases of benign pleural effusions, and 20 cases of unexplained pleural effusions among the 90 participants. The area under the ROC curve for fluorescence imaging of ErNP@SiO2‐ICG was 0.814 (95% confidence interval: 0.708–0.920). The fluorescence imaging sensitivity and specificity of ErNP@SiO2‐ICG were 0.814 (95% CI: 0.652–0.872), while the area under the ROC curve for pleural fluid cytology was 0.729 (95% CI: 0.607–0.850). The area under the ROC curve for the ErNP@SiO2‐ICG NIR fluorescent probe showed good compliance with pathologic findings (Kappa = 0.629, p < 0.001). The results of the confusion matrix constructed based on this threshold showed a positive predictive value of 82.40% and a negative predictive value of 80.60%, with a false‐positive rate of 17.60% and a false‐negative rate of 19.40%.

The ErNP@SiO2‐ICG rare earth‐doped nano‐probe for NIR fluorescence imaging exhibits exceptional accuracy in the detection of MPE, thereby providing an innovative technological approach for the future identification of this condition.