Silicon nanoparticles: applications in cell biology and medicine

Abstract

Abstract:In this review, we describe the synthesis, physical properties, surface functionalization, and biological applications of silicon nanoparticles (also known as quantum dots). We compare them against current technologies, such as fl uorescent organic dyes and heavy metal chalcogenide-based quantum dots. In particular, we examine the many different methods that can be used to both create and modify these nanoparticles and the advantages they may have over current technologies that have stimulated research into designing silicon nanoparticles for in vitro and in vivo applications.

Influence of Phase Transformations on Incipient Plasticity of Si-Nanospheres

“…1) matching the experimentally observed elevated yield-point stress of the Si nanospheres [9,10]. This value is almost twice higher than the hardness of the bulk Si [9], while nearly identical to the magnitude of peak stress reached at the point of elastic-plastic transition in previous simulations [15].…”

“…The enhanced hardness of Si nanospheres is consistent with the known phenomenon of yield stress increase due to the decrease of dimensions of deformed volumes [9,10]. However, the reversible plasticity exhibited by the compressed Si nanoparticles [9,10] cannot be justified in the framework of the theories pertinent to the bulk Si surfaces. Gerberich et al [9,10] proposed a model of dislocation-driven onset of plasticity accounting for the unusual behavior of Si nanoparticles.…”

“…In order to model processes initiated in stressed Si nanospheres we performed molecular dynamics (MD) simulations (LAMMPS simulation code) designed to match experimental conditions of previously reported nanocompression tests [9,10]. MD interactions between silicon atoms were modeled using the Stillinger-Weber (S-W) potential [11] accurately reflecting elastic behavior and generation of lattice defects in silicon [12].…”

“…Recent nanoscale compression [9,10] and nanoindentation observations [7] demonstrated that deformation of silicon nanovolumes is markedly different from behavior of the * corresponding author; e-mail: dariusz.chrobak@us.edu.pl bulk material. The enhanced hardness of Si nanospheres is consistent with the known phenomenon of yield stress increase due to the decrease of dimensions of deformed volumes [9,10]. However, the reversible plasticity exhibited by the compressed Si nanoparticles [9,10] cannot be justified in the framework of the theories pertinent to the bulk Si surfaces.…”

“…However, the reversible plasticity exhibited by the compressed Si nanoparticles [9,10] cannot be justified in the framework of the theories pertinent to the bulk Si surfaces. Gerberich et al [9,10] proposed a model of dislocation-driven onset of plasticity accounting for the unusual behavior of Si nanoparticles. Following the latter idea, we provide a detailed atomistic account of stress-driven deformation in Si nanoparticles based on experimental evidence indicating the effect of nanoscale confinement.…”