This study aimed to develop novel, biodegradable, antiseptic-loaded and low-cost scaffolds using a direct ink writing (DIW) technique for antibacterial applications. Polylactic acid/cellulose acetate (PLA/CA) mixtures with different composition ratios were prepared, and the effect of CA content on the rheological behaviors of the inks was investigated. The printability of the prepared DIW inks was improved with the addition of the appropriate amount of CA, since the formation of hydrogen bonding 3D network between PLA and CA. As a result, a liquid form ink consisting of majority of PLA and minority of CA which was prepared and printed for the first time through DIW technique. Afterwards, the antimicrobial agent, 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC) was incorporated into the inks for preventing bacterial infections, which showed excellent stability and effective antibacterial activity against S. aureus and E. coli O157:H7 in a short time. Owning the ease of fabrication and the biocidal property, our 3D printed scaffolds will have a wide range of potential applications in the field of food packaging, communal facilities, medical equipments, and biomedical materials.