Quantitative detection of α1-acid glycoprotein (AGP) level in blood plasma using SERS and CNN transfer learning approach

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive tool in medical diagnostics and bioanalysis fields, aimed at the qualitative detection of relevant biomolecules. However, quantitative SERS analysis of complex (bio)samples is a more challenging and, in many cases, almost impossible task, requiring functional SERS substrates or advanced spectral data analysis. In this work, we propose the combination of a functional SERS substrate, capable of trapping target biomolecules, with CNN transfer learning for quantitative detection of the relevant alpha 1-acid glycoprotein (AGP, also known as orosomucoid) in human serum. As a SERS substrate, the plasmonic gold grating was functionalized with boronic acid moieties to entrap target AGP. The functionality of the substrate was tested on two model solutions: a solution containing saccharides as competing molecules and human serum with added AGP, which is close to real samples. The convolution neural network (CNN) was previously trained on a huge number of (bio)samples. Then CNN transfer learning was used to quantify AGP concentration in model samples, as well as in human serum. Developed strategy is able to identify the alarming increase of AGP concentration in an express and medically decentralized way, on short time and under lack of spectral data. Generally, the proposed combination of SERS and machine transfer learning could be expanded to a range of alternative cases, where the collection of real samples is restricted and can be substituted by the measurements of similar model systems, without loss of analysis reliability.

Automated summary

In this study, a combination of functional SERS substrate and CNN transfer learning was proposed for quantitative detection of a specific biomolecule in human serum. The method allows for quick and decentralized identification of increased biomolecule concentration, making it a valuable tool for analysis in the absence of spectral data.