A blended FC-V-50 and TZ-001 polymer-based microdisk laser was fabricated by the ink-jet printing method and used for biosensing applications. The FC-V-50 polymer has a negative charge due to the presence of carboxyl functional groups, and the TZ-001 polymer has a positive charge due to the tertiary amine group at a pH of seven. In biosensing applications, non-specific adsorption due to opposite charges of biomolecules and microdisk surfaces can adversely affect the performance of the biosensor. By mixing FC-V-50 and TZ-001 polymers in different ratios, the microdisk surface charge was controlled, and the non-specific adsorption of bovine serum albumin and lysozyme was studied. In addition, the label-free biosensing of streptavidin was demonstrated using a blended polymer-based microdisk laser. This work reports, to the best of our knowledge, the first demonstration of a blended polymer microdisk laser for controlling the non-specific adsorption of biomolecules.