Surface-enhanced Raman spectroscopy analysis of glucose in spent embryo culture medium: correlation with embryo developmental potential.

IntroductionAccurate and non-invasive assessment of early embryonic metabolic biomarkers and their association with developmental potential remains a major challenge in assisted reproductive technology (ART). Glucose is a key metabolic component associated with embryo developmental competence, and its residual level in spent embryo culture medium (SECM) may reflect embryonic metabolic activity and provide valuable information for embryo assessment.MethodsIn this study, surface-enhanced Raman spectroscopy (SERS) was used for the relative quantification of residual glucose in SECM. A mouse model was applied to compare residual glucose levels between blastocyst-forming and non-blastocyst-forming groups. In addition, quantitative SERS (qSERS) stratification based on an optimized threshold was performed to evaluate the association between residual glucose levels and blastocyst developmental outcomes.ResultsThe results demonstrated the feasibility and analytical performance of the SERS-based metabolic analysis, with an analytical repeatability relative standard deviation (RSD) of 1.22% and a regression goodness-of-fit R 2 of 0.996. In the mouse model, residual glucose levels differed significantly between the blastocyst-forming and non-blastocyst-forming groups, indicating that glucose utilization is associated with blastocyst formation. Furthermore, qSERS stratification using the optimized threshold supported the association between residual glucose levels and blastocyst developmental outcomes, with a mean accuracy of 69.13%.DiscussionThese findings suggest that residual glucose in SECM is an informative extracellular metabolic feature for evaluating embryo developmental potential. However, the predictive capacity of glucose alone remains limited, and future embryo assessment should integrate additional metabolic or morphokinetic indicators for a more comprehensive evaluation. Overall, this SERS-based glucose sensing strategy provides a technical basis for future non-invasive and multi-parametric embryo assessment in ART.