**4. Conclusions**

In this study, we developed an experimental setup, a program for collecting and displaying data, and an experimental technique for assessing the concentration of green indocyanine in various solutions. The experimental studies involved measurements with an aqueous dye, an albumin solution, and blood plasma correlated with the data from a commercial DU® 800 UV/Visible spectrophotometer. The main (advantages) of a device are cost-effectiveness, simplicity of use and quick real-time presentation of the results. The developed system will make it possible to diagnose liver function and predict its recovery with higher accuracy compared with existing approaches.

**Author Contributions:** Funding acquisition, supervision, E.V.; methodology, formal analysis, V.O.; investigation, I.K.; experiment in Russian Research Center for Radiology and Surgical Technologies, L.K.; writing—original draft preparation, E.S. and I.K.; and machine learning consultation and data evaluation, Z.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research work was supported by Peter the Great St. Petersburg Polytechnic University in the framework of the Program "5-100-2020".

**Acknowledgments:** We express our gratitude to the Russian Research Center for Radiology and Surgical Technologies for providing biological samples, to S.V. Ermak for comprehensive assistance and valuable scientific advice, and to E.K. Nepomnyashchaya for illustration design.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders/sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
