NOVELTY - The structure has porous object with regions arranged adjacent along axis of object. The regions have porous property selected from pore size, porosity and pore orientation. The porous object has rectangular or circular cross-section that is perpendicular to axis, and aspect ratio not less than 4. The cross-section has lateral dimension of not more than 5 microns.    USE - Porous and non-porous nano-structure used in fabrication of nanowire such as drug delivery needle, nanoneedle bar-coded wire and drug delivery vehicle for delivering active agent such as therapeutic agent and imaging agent. Can also be used in electro-optical device, sensor, solar cell, electronic device and nanomechanical device.    ADVANTAGE - The structure can be manufactured effectively so that functionality is improved.    DETAILED DESCRIPTION - The structure has porous object that is selected from porous semiconductor object, silicon porous wire, biodegradable object, ribbon or belt, and is positioned on silicon substrate. The pore size of region is less than 100 nm. The transition region between two regions is less than 10 nm long along the axis of object. The pores of region are provided with nanoparticles having quantum dots. An independent claim is included for method of making a porous object which involves obtaining etchable substrate, forming on surface of substrate patterned porosification assisting metal layer that has opening. The substrate is exposed to etching solution which dissolves patterned porosification assisting layer to form metal containing etching solution. The metal containing etching solution is configured to porosify portion of substrate and to etch out portion of substrate to form porous object having cross-section determined by opening. The substrate is provided with uniform doping level with resistivity of greater than 0.02 Omega cm. A shadow mask that defines cross-section of opening and having porosification assisting metal layer formed over is deposited on surface of substrate by microlithography or nanolithography. The stencil mask is removed to form patterned porosification assisting metal layer. The porosification assisting metal layer is formed over stencil mask by electroless chemical process or physical vapor deposition. The stencil mask is provided with dielectric material made of silicon nitride. The patterned porosification assisting metal is made of noble metal with thickness of less than 50 nm. The opening is provided with lateral dimension of no more than 5 microns. The etching solution is selected from hydrogen fluoride and oxidizer such as hydrogen peroxide and is provided with surfactant such as ethanol. The parameter is selected by selecting concentrations of components of etching solution before exposing.    DESCRIPTION OF DRAWING(S) - The drawing shows a graph illustrating relationship between relative pressure and volume obtained during measurement of pore size.