Desenvolvimento e validação de dispositivos de transporte e armazenamento de saliva a seco (DTASS) para recuperação de metabólitos da fração lipídica salivar utilizando espectrometria de massas

Abstract

Introduction: The use of saliva as a diagnostic biofluid has attracted growing scientific interest due to its simplicity, speed, safety, non-invasiveness, and ease of storage, and it has the potential to reflect metabolic changes occurring in the body. Furthermore, the presence of various metabolites and lipids makes this fluid a promising source for the investigation of biomarkers associated with diferente physiological and pathological conditions. Objective: To develop and optimize a dry saliva transport and storage device (DTASS) for the recovery of metabolites from the lipid-rich fraction of saliva, evaluating different extraction conditions based on mixtures of dichloromethane and methanol. Method: This is a cross-sectional study conducted with healthy individuals treated at the Endocrinology Outpatient Clinic of the Hospital de Clínicas of the Federal University of Uberlândia. Samples of unstimulated saliva were collected using a standardized method and applied to different paper supports designed for drying and preserving the sample. Subsequently, different extraction conditions were tested using combinations of dichloromethane and methanol in various ratios, with the aim of identifying the most efficient strategy for recovering lipid compounds. After the preparation step, the extracts obtained were analyzed by liquid chromatography coupled with mass spectrometry, allowing for the characterization of the metabolic and lipid profiles of the samples. Results: The 1:1 ratio (dichloromethane:methanol) showed greater efficiency in the recovery of lipid metabolites compared to the 2:1 ratio, both on NuPAD paper (70.5%) and on Whatman 903 (69.8%). In the comparison between the platforms under the 1:1 condition, Whatman 903 showed higher relative abundance for 56.3% of the identified metabolites, while NuPAD showed higher abundance for 43.7%. Despite the slight superiority of Whatman 903, NuPAD demonstrated similar analytical performance, highlighting its potential as a low-cost alternative for metabolomic analyses of the lipid fraction. Conclusions: DTASS is a promising tool for dry-saliva-based lipidomic applications, offering an accessible and efficient approach to the preservation of biological samples. Its use may contribute to the expansion of studies aimed at biomarker discovery, facilitating the development of more practical diagnostic strategies and broadening the scope of precision medicine applications in various clinical and scientific contexts.