Nanoparticles offer numerous advantages in various fields of science, particularly in medicine. Over recent years, the use of nanoparticles in disease diagnosis and treatments has increased dramatically by the development of stimuli-responsive nano-systems, which can respond to internal or external stimuli. In the last 10 years, many preclinical studies were performed on physically triggered nano-systems to develop and optimize stable, precise, and selective therapeutic or diagnostic agents. In this regard, the systems must meet the requirements of efficacy, toxicity, pharmacokinetics, and safety before clinical investigation. Several undesired aspects need to be addressed to successfully translate these physical stimuli-responsive nano-systems, as biomaterials, into clinical practice. These have to be commonly taken into account when developing physically triggered systems; thus, also applicable for nano-systems based on nanomaterials. This review focuses on physically triggered nano-systems (PTNSs), with diagnostic or therapeutic and theranostic applications. Several types of physically triggered nano-systems based on polymeric micelles and hydrogels, mesoporous silica, and magnets are reviewed and discussed in various aspects.

A new catalytic system based on palladium nanoparticles supported on polymeric N-heterocyclic carbene-grafted silica (Si–PNHC–Pd) is introduced. Aminopropylsilica was reacted with benzoylchloride to form acrylamidopropylsilica. Onto this functionalized silica, vinylimidazole monomer was copolymerized by free radical polymerization. Poly(vinylimidazole)-grafted silica was treated with methyl iodide to form a quaternary salt of poly(vinylimidazole). Si–PNHC–Pd was obtained by subsequent treatment of imidazolium salt with PdCl₂. Determination of Pd content was performed using an inductively coupled plasma (ICP) analyzer and the crystalline character was determined by an XRD technique. The topography and particle size of the catalyst was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). TEM images showed that palladium was dispersed through the polymer surface in nano particle size. This catalytic system exhibited excellent activity in Heck and Sonogashira coupling reactions with various aryl halides. The catalyst was successfully re-used up to 12 runs without appreciable change in its activity. High efficiency of the catalyst along with high yields of products, easy purification, large scale synthesis and high TON and TOF are among the advantages of this heterogeneous catalyst.