We have successfully synthesised one-dimensional single crystals of monoclinic phase titanium dioxide nanostructures (TiO2-B), prepared by a hydrothermal process. Morphological characterization was carried out by atomic force and scanning and transmission electron microscopy techniques. In order to study the crystalline structure, samples were calcined at 500 degrees C in an air-filled chamber. X-ray diffraction results indicated that as-prepared samples presented diffraction patterns of hydrate hydrogen titanate and those calcined at 500 degrees C exhibitedthe TiO2-B and anatase phases, confirmed by Raman spectroscopy. Scanning electron microscopy results showed that the one-dimensional nanostructures had high contrast and uniform widths for those synthesised and calcined, indicating the formation of a phase of monocrystals. Besides, a proof of the antibacterial effect was carried out of the monoclinic phase of TiO2-B on Escherichia coli pure cultures, where the viability of the bacterium decreases in presence of TiO2-B nanostructures plus UV illumination. Monocrystals did not change after photocatalytic tests, suggesting a possible application as long-term antibacterial protection. ; Fundacion Andes C-13876 FONDECYT 1080401 Anillo ACT1204 FIC-R: "Transferencia Desarrollo de Nanotransistores Basados en Cables Bacterianos del Desierto" BIP 30412822-0 DGIP of the Universidad Catolica del Norte