Low-temperature solution growth of TiO2 films provides unique surface functionalities for base materials. It involves multiple stages of crystal growth at various length scales and is of particular help for the substrates that may not survive high processing temperatures. Having a fundamental understanding of the mechanisms involved in those stages is essential to obtain desirable TiO2 phases and functional performances. In this review, we report four major phases of TiO2 for their nanostructures and photocatalytic activities that are essential in antimicrobial properties. To further improve the photocatalytic activities through more efficient electron–hole separation, the TiO2-based hybrid structures are adopted for creating heterojunction interfaces between heterophases of TiO2 (i.e., rutile, anatase, brookite, TiO2 (B)), between TiO2 and other semiconductor oxides (e.g., ZnO, SnO2, Ce2O3, NiO), or between TiO2 and nanometals (e.g., Cu, Ag, Ni). For such hybrid structures, 1D TiO2 rutile or TiO2 (B) nanowires, nanorods, or nanotubes can be fabricated as a ‘core’ structure using a hydrothermal method or other solution grown processes. To create a hybrid configuration of TiO2 with other semiconductor oxides, the energy level diagrams of oxides are proposed. Metal nanoparticles have been extensively used as an antimicrobial agent, so the hybrid configuration between TiO2 and metal nanoparticles can provide a synergistic effect on the antibacterial performance with additional toxicity modes different from the photocatalytic reactions via generation of reactive oxygen species (ROS). The size and shape of the surface (or ‘shell’) feature in addition to its chemistry seem to play an important role in inactivating the bacterial pathogens, for which nanostructured surface can be optimally designed for the TiO2 core structure. Especially, the brookite and TiO2 (B) phases are much less studied than their rutile and anatase counterparts, thereby providing unique opportunities for further development of antimicrobial surfaces that can be nonselective to types of microorganisms.