Me. Rev. Stat. tit. 20-A, § 1315

A contract made by the school directors in a school administrative district during the term of a member who is pecuniarily interested in that contract, either directly or indirectly, shall be void, unless the board of directors has advertised for sealed bids for that contract and that advertisement for sealed bids has been published at least 5 days prior to the date set for closing of bids in a newspaper having general circulation within the school administrative unit.