Optical tweezers have been proved to be an efficient tool for micro-objects manipulating and has found lots of applications mainly in biology. However applications of this unique method both in solid state physics are not so wide-spread. The main idea of optical tweezering lies in the trapping of microobjects utilizing forces of optical pressure. If the trapped particle is transparent this method turns out to be non-disturbing way of diagnostics of single objects of micrometer scale. Microparticle is usually placed into cavity with liquid and is trapped by strongly focused beam. Physical properties of single functional micro- and nanoparticles, for example, magnetic ones can differ significantly from the properties of both bulk samples and thin films, and at the same time are of the greatest interest in the whole range of applications connected with novel micromagnetic devices. It makes the problem of single microparticles diagnostics really challenging. In this presentation new advantages and new applications of optical tweezers are discussed. First, application of optical tweezers for magnetic micro- and nanoparticles diagnostics and planar nanostructures fabrication is presented. The ability of magnetic field manipulation of the trapped particles is demonstrated. It is demonstrated that such approach turns out to be a unique tool for revealing magnetic properties of ferrimagnetic nanosized objects which can't be obtained by conventional techniques such as for example magnetic force microscopy or VSM measurements of bulk samples. The ways of optical torque translation from input radiation to the trapped particles is considered. Second, experimental analysis of recoil effects induced by fluorescence photons is presented. The momentum transfer to a scatterer from fluorescence photons was detected using an optical system that permits one to simultaneously measure the radiation force exerted on and fluorescence emission from the scatterer. Finally, new applications of optical tweezers as photonic force microscope for direct measurements of red blood cell (dis)aggregation forces is discussed. Quantitative measurements of piconewton-range interaction forces between RBCs in pair aggregates are performed. Statistical analysis of disaggregation induced by optical trap movement reveals four scenarios of disaggregation, depending on the aggregation properties of RBCs. Experimental dependence of aggregation forces on the distance between two disaggregating RBCs is in a good agreement with the model of ringshaped interaction surfaces of RBCs in the pair aggregate.