A printing system which includes a printer connected with at least one user terminal by a wire or wirelessly to print printing data transmitted from the user terminal, prevents printing of data before a special printing job and a printing method for the same. Optical tweezers based on one or more Fresnel zone plates may be integrated with a microfluidic structure of various geometries so as to form one or more optical traps within a fluid medium contained by the microfluidic structure. The method includes preparing a polymeric polysaccharide in a buffer to create a polymer solution or gel suspending particles in the gel and selecting a rheology profile for the desired tissue region.