The paper presents a short overview of the theoretical, numerical and experimental works on the critical behaviour of a dilute polymer solution of long-flexible polymer chains confined in semi-infinite space restricted by a surface or in a slit geometry of two parallel walls with different adsorbing or repelling properties in respect for polymers as well as in a solution of mesoscopic spherical colloidal particles of one sort or two different sorts. We discuss the application of the massive field theory approach in a fixed space dimensions d = 3 up to one loop order for such topics as: (a) the investigation of the elastic properties of real polymer chain immersed in a good solvent and anchored by one end to the surface and with other end being under tension of the external applied force as it is usually takes place in the single -molecule force spectroscopy experiments; (b) the calculation of the monomer density profiles, the depletion interaction potentials and the depletion forces which arise in a dilute polymer solution immersed in confined geometries, like slit of two parallel walls with different adsorbing or repelling properties in respect for polymers; (c) the investigation of monomer density profiles and the depletion forces which arise in the polymer-colloid mixtures in the case of the mesoscopic spherical colloidal particles of one sort or two different sorts. The presented results give possibility better to understand the complexity of physical effects arising from confinement and indicate about the interesting and nontrivial behavior of linear polymer chains in confined geometries and are in good qualitative and quantitative agreement with previous theoretical investigations, results of Density Functional Theory (DFT), Monte Carlo (MC) simulations and experimental data based on the single molecular atomic force spectroscopy (AFM) and the total internal reflection microscopy (TIRM). Besides, the obtained results have important practical applications for better understanding of the elastic properties of the individual macromolecules, networks, gels and brush layers as well as indicate about possibility of application in production of new types of nano-and micro-electromechanical devices.