Uptake and Toxicity Studies of Poly‐Acrylic Acid Functionalized Silicon Nanoparticles in Cultured Mammalian Cells

Abstract

Poly‐acrylic acid (PAAc) terminated silicon nanoparticles (SiNPs) have been synthesized and employed as a synchronous fluorescent signal indicator in a series of cultured mammalian cells: HHL5, HepG2 and 3T3‐L1. Their biological effects on cell growth and proliferation in both human and mouse cell lines have been studied. There was no evidence of in vitro cytotoxity in the cells exposed to PAAc terminated SiNPS when assessed by cell morphology, cell proliferation and viability, and DNA damage assays. The uptake of the nanocrystals by both HepG2 and 3T3‐L1 cells was investigated by confocal microscopy and flow cytometry, which showed a clear time‐dependence at higher concentrations. Reconstructed 3‐D confocal microscope images exhibited that the PAAc‐SiNPs were evenly distributed throughout the cytosol rather than attached to outer membrane. This study provides fundamental evidence for the safe application and further modification of silicon nanoparticles, which could broaden their application as cell markers in living systems and in micelle encapsulated drug delivery systems.

Small Silicon, Big Opportunities: The Development and Future of Colloidally‐Stable Monodisperse Silicon Nanocrystals

“…Silicon was first used to demonstrate in vitro biological imaging in 2004, using water‐soluble polyacrylic acid‐terminated ncSi 80. Since then, a variety of developments have been reported for the use of ncSi in biomedical applications including studies of cytotoxicity, cellular uptake and accumulation, and in vivo targeting and imaging 8, 9, 14, 81, 82. Our group also recently contributed to this growing field,39 reporting key changes to our straightforward synthesis involving the thermal processing of sol‐gel polymers, HF etching, and hydrosilylation,37 in order to achieve NIR emitting ncSi for biological fluorescence imaging.…”

“…The effects of quantum and spatial confinement result in the widening of the electronic bandgap and a blue shift in photoluminescence for particles with decreasing size, and as a result, the archetypical CdSe and PbS nanocrystals have shown great promise in various optoelectronic and biomedical devices 4–7. Silicon, which has the potential to be similarly promising in a variety of applications, offers the added benefits of being earth abundant, relatively inexpensive, purportedly less toxic,8, 9 and compatible with silicon electronics. As a result, the discovery of colour‐tunable emission from “small” silicon ignited the development and study of a variety of luminescent forms of silicon for applications such as light‐emitting diodes (LEDs), lasers, thermoelectrics, solar cells, and biomedical imaging 10–14.…”

Size-Dependent Oxidation of Monodisperse Silicon Nanocrystals with Allylphenylsulfide Surfaces

“…Luminescent, colloidally stable silicon nanocrystals are a new class of materials with a wide range of applications from medical imaging to optoelectronics such as light emitting diodes (LEDs) and solar cells . In contrast to II–VI and III–V semiconductor nanocrystals, the advantage of silicon, the element that dominates the microelectronics and photovoltaic industry, is its nontoxicity, earth abundance and low cost.…”

Structural, spectroscopic and cytotoxicity studies of TbF3@CeF3 and TbF3@CeF3@SiO2 nanocrystals

“…Increased optical response, higher luminescence and longer decay times have been observed when the cores of luminescent Ln 3+ -doped materials are covered by SiO 2 shells (Wang et al 2009). As a result, biological effects of silica nanoparticles have become the subject of growing interest in recent years (Wang et al 2012). …”