Shape and surface effects on the cytotoxicity of nanoparticles: Gold nanospheres versus gold nanostars

Abstract

Gold nanoparticles are materials with unique optical properties that have made them very attractive for numerous biomedical applications. With the increasing discovery of techniques to synthesize novel nanoparticles such as star-shaped gold nanoparticles for biomedical applications, the safety and performance of these new nanomaterials must be systematically assessed before use. In this study, gold nanostars (AuNSTs) with multibranched surface structures were synthesized, and their influence on the cytotoxicity of human skin fibroblasts and rat fat pad endothelial cells (RFPECs) were assessed and compared with that of gold nanospheres (AuNSPs) with unbranched surfaces. Results showed that the AuNSPs with diameters of approximately 61.46 nm showed greater toxicity with fibroblast cells and RFPECs compared with the synthesized AuNSTs with diameters of approximately 33.69 nm. The AuNSPs were lethal at concentrations of 40 μg/mL for both cell lines, whereas the AuNSTs were less toxic at higher concentrations (400 μg/mL). The calculated IC50 (50% inhibitory concentration) values of the AuNSPs exposed to fibroblast cells were greater at 1 and 4 days of culture (26.4 and 27.7 μg/mL, respectively) compared with the RFPECs (13.6 and 13.8 μg/mL, respectively), indicating that the AuNSPs have a greater toxicity to endothelial cells. It was proposed that possible factors that could be promoting the reduced toxicity effects of the AuNSTs to fibroblast cells and RFPECs, compared with the AuNSPs may be size, surface chemistry, and shape of the gold nanoparticles. The reduced cell toxicity observed with the AuNSTs suggests that AuNSTs may be a promising material for use in biomedical applications.

Synthesis of a novel glucose capped gold nanoparticle as a better theranostic candidate

“…The present data indicating that higher concentration of citrate capped gold nanoparticles are toxic to HCT 116 cells, is in perfect harmony with the findings of some earlier researchers who reported similar observations and postulated that such toxicity might be associated with the acidic nature of citrate, the capping agent of the concerned nanoparticles [67]. Toxicity imparted by citrate –AuNp may also be due to the spherical shape of the particles supporting some earlier study who reported higher toxicity of gold nanospheres when compared to that of gold nanostars [68]. Interestingly, the present results reflect the potential of two of the synthesized nanoparticles to stimulate cell growth.…”

DLS and zeta potential – What they are and what they are not?

“…Hence, adequate characterization of the nanoparticles (NPs) is essential in order to obtain reliable data with high translatory output. This also becomes pertinent due to the safety concerns which are often attributed to the physical (e.g., particle size [3], surface charge [4], shape [5]) and chemical (e.g., surface functionalization with different ligands including PEGylation [6], impurity [7], crystallinity [8]) properties of NPs. Sufficient characterization helps to explain the NPs as chemical species which are highly reactive and exhibit unprecedented characteristics compared to bulk materials (e.g., conductivity [9], fluorescence [10], magnetism [11]).…”

Shape-dependent antibacterial effects of non-cytotoxic gold nanoparticles

“…27,34,35 As with all NPs, AuNPs have varying degrees of cytotoxicity, which is dependent on their size, [36][37][38] surface chemistry, 35,[39][40][41] shape 34,42,43 and most importantly dosage. 18 Various trends in size-dependent cytotoxicity have been observed, most commonly showing an increased cytotoxicity for smaller sized NPs, particularly those ,5 nm.…”