Note 8 – Notes Payable

As of June 30, 2026 and December 31, 2025, notes payable consisted of the following:

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Avenue Loan

On June 17, 2025, the Company entered into the Fourth Amendment of the Loan and Security Agreement with Avenue Venture Opportunities Fund, L.P., and Avenue Venture Opportunities Fund, L.P. II (the “Avenue Loan”) which, among other things, extended the maturity date of the loans to July 1, 2028; provided for an interest - only period from July 1, 2025 until January 31, 2027 (principal payments begin in February 2027); and reduced the interest rate from 12.0% to 8.0% (payable half in cash and half in kind). The effective interest rate on the Avenue Loan was 8.5% for each of the three and six months ended June 30, 2026, excluding the amortization of the debt discount, and 9.3% for each of the three and six months ended June 30, 2026, including the amortization of the debt discount.

As of June 30, 2026, total principal under the Avenue Loan consists of original loan principal of $8,158,195, plus $350,294 of paid-in-kind interest.

The Avenue Loan matures as follows and includes $809,341 of paid-in-kind interest accrued through maturity.

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During the three months ended June 30, 2026 and 2025, the Company recorded interest expense related to the Avenue Loan of $226,368 (which includes $55,460 of amortization of debt discount) and $528,410 (which includes $307,536 of amortization of debt discount), respectively. During the three months ended June 30, 2026, interest expense in the amount of $85,454 was added to the principal balance outstanding.

During the six months ended June 30, 2026 and 2025, the Company recorded interest expense related to the Avenue Loan of $449,172 (which includes $110,921 of amortization of debt discount) and $1,109,909 (which includes $585,508 of amortization of debt discount), respectively. During the six months ended June 30, 2026, interest expense in the amount of $169,125 was added to the principal balance outstanding.

FIRST Insurance Funding Loan

On February 24, 2026, the Company issued a note payable in the amount of $598,055 for the purchase of a directors and officers’ liability insurance policy (the “2026 D&O Loan”). The note accrues interest at a rate of 6.15% per year and matures on December 24, 2026. The 2026 D&O Loan is payable in ten monthly payments of $61,504 consisting of principal and interest. Interest expense for the three and six months ended June 30, 2026 was $7,392 and $10,457, respectively.