Exhibit 10.23

CERTAIN INFORMATION IDENTIFIED IN THIS DOCUMENT, MARKED BY BRACKETS AND ASTERISKS (“[***]”), HAS BEEN EXCLUDED PURSUANT TO ITEM 601(B)(10) OF REGULATION S-K UNDER THE SECURITIES ACT OF 1933, AS AMENDED, BECAUSE IT IS (I) NOT MATERIAL AND (II) WOULD LIKELY CAUSE COMPETITIVE HARM TO THE REGISTRANT IF PUBLICLY DISCLOSED.

FOURTH AMENDMENT TO

RESEARCH FUNDING AND OPTION AGREEMENT

This Fourth Amendment to that certain Research Funding and Option Agreement (the “Fourth Amendment”) is entered into as of November 1, 2025 (the “Fourth Amendment Effective Date”) by and between The Scripps Research Institute, a California nonprofit public benefit corporation located at 10550 North Torrey Pines Road, La Jolla, California 92037 (“TSRI”), and Xenetic Biosciences, a for-profit corporation located at 945 Concord Street, Framingham, Massachusetts 01701 (“Sponsor”).

Recitals

Whereas, TSRI and Sponsor entered into that certain Research Funding and Option Agreement dated March 10, 2023, and that certain First Amendment dated June 1, 2024, and that certain Second Amendment dated November 1, 2024, and that certain Third Amendment dated May 1, 2025 (together the “Agreement”);

Whereas, TSRI and Sponsor wish to amend the Agreement in the manner set forth in this Fourth Amendment.

Agreement

Now Therefore, in consideration of the mutual promises set forth, the parties hereto agree as follows:

In Witness Whereof, the parties have executed this Fourth Amendment as of the Fourth Amendment Effective Date.

Exhibit A

Research Program