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Peptide-biphenyl hybrid-capped AuNPs: stability and biocompatibility under cell culture conditions.

Connolly M, Pérez Y, Mann E, Herradón B, Fernández-Cruz ML, Navas JM - Nanoscale Res Lett (2013)

Bottom Line: Moreover, these AuNPs have unique biological effects on Hep G2 cells while showing low toxicity.The production of ROS along with supporting optical microscopy images suggests cellular interaction/uptake of these particular AuNPs.Future research efforts should further test this hypothesis, as such interaction/uptake is highly relevant in drug delivery systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departamento de Medio Ambiente, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de la Coruña Km 7,5, Madrid 28040, Spain. yolanda.cortes@urjc.es.

ABSTRACT
In this study, we explored the biocompatibility of Au nanoparticles (NPs) capped with peptide-biphenyl hybrid (PBH) ligands containing glycine (Gly), cysteine (Cys), tyrosine (Tyr), tryptophan (Trp) and methionine (Met) amino acids in the human hepatocellular carcinoma cell line Hep G2. Five AuNPs, Au[(Gly-Tyr-Met)2B], Au[(Gly-Trp-Met)2B], Au[(Met)2B], Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B], were synthesised. Physico-chemical and cytotoxic properties were thoroughly studied. Transmission electron micrographs showed isolated near-spherical nanoparticles with diameters of 1.5, 1.6, 2.3, 1.8 and 2.3 nm, respectively. Dynamic light scattering evidenced the high stability of suspensions in Milli-Q water and culture medium, particularly when supplemented with serum, showing in all cases a tendency to form agglomerates with diameters approximately 200 nm. In the cytotoxicity studies, interference caused by AuNPs with some typical cytotoxicity assays was demonstrated; thus, only data obtained from the resazurin based assay were used. After 48-h incubation, only concentrations ≥50 μg/ml exhibited cytotoxicity. Such doses were also responsible for an increase in reactive oxygen species (ROS). Some differences were observed among the studied NPs. Of particular importance is the AuNPs capped with the PBH ligand (Gly-Tyr-TrCys)2B showing remarkable stability in culture medium, even in the absence of serum. Moreover, these AuNPs have unique biological effects on Hep G2 cells while showing low toxicity. The production of ROS along with supporting optical microscopy images suggests cellular interaction/uptake of these particular AuNPs. Future research efforts should further test this hypothesis, as such interaction/uptake is highly relevant in drug delivery systems.

No MeSH data available.


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Optical microscope images of the morphology of Hep G2 cells. (a) untreated (b) after 24-h incubation with chloramine-T (positive control) and after 24-h exposure to AuNP preparations (c) Au[(Gly-Trp-Met)2B], (d) Au[(Gly-Tyr-TrCys)2B], (e) Au[(Gly-Tyr-Met)2B], (f) Au[(Met)2B] and (g) Au[(TrCys)2B] in EMEM/S-; asterisk and bold letters are used to signal the most stable AuNP.
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Figure 10: Optical microscope images of the morphology of Hep G2 cells. (a) untreated (b) after 24-h incubation with chloramine-T (positive control) and after 24-h exposure to AuNP preparations (c) Au[(Gly-Trp-Met)2B], (d) Au[(Gly-Tyr-TrCys)2B], (e) Au[(Gly-Tyr-Met)2B], (f) Au[(Met)2B] and (g) Au[(TrCys)2B] in EMEM/S-; asterisk and bold letters are used to signal the most stable AuNP.

Mentions: An optical microscope was used to view the cells and NPs in EMEM/S- at various time points throughout the exposure. The study was performed only for exposures using EMEM/S- because of evidence of higher instability and toxicity of AuNPs under these conditions. Figure 10 shows Hep G2 cells after 24 h of incubation with NP concentrations of 100 μg/ml. The AuNPs Au[(Met)2B] formed large agglomerates that covered almost the entire well (Figure 10f). While this phenomenon made it difficult to view the cells, evidence of cell rounding was observed when compared to the untreated cells (Figure 10a). However, the cells most dramatically affected were those exposed to Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B] (Figure 10d,g, respectively). Unique and distinct dark assemblages in the cells exposed to Au[(Gly-Tyr-TrCys)2B] (Figure 10d) were evident. The size of Au[(Gly-Tyr-TrCys)2B] agglomerates did not permit NP visualisation in a cell-free Au[(Gly-Tyr-TrCys)2B] suspension (Figure 8). This observation led us to believe that the assemblies, visible when Au[(Gly-Tyr-TrCys)2B] was in contact with cells (Figure 10d), are a result of cell damage or are formed from cellular interaction with these AuNPs. The cells exposed to Au[(TrCys)2B] (Figure 10g) showed the characteristic appearance of cells treated with chloramine-T (Figure 10b), the chemical used in this study as a positive control. The cells rounded completely into a blister-like structure. However, the AuNPs did not appear to interact with the cells and instead were suspended in the medium. The morphology of Hep G2 cells incubated with Au[(Gly-Trp-Met)2B] was comparable with that of untreated cells, despite the presence of some dark assemblages (Figure 10c). Cells exposed to Au[(Gly-Tyr-Met)2B] (Figure 10e) also seemed to retain healthy cellular features, with NPs settled on clear areas of the 96-well plate, thereby suggesting limited NP-cellular interaction.


Peptide-biphenyl hybrid-capped AuNPs: stability and biocompatibility under cell culture conditions.

Connolly M, Pérez Y, Mann E, Herradón B, Fernández-Cruz ML, Navas JM - Nanoscale Res Lett (2013)

Optical microscope images of the morphology of Hep G2 cells. (a) untreated (b) after 24-h incubation with chloramine-T (positive control) and after 24-h exposure to AuNP preparations (c) Au[(Gly-Trp-Met)2B], (d) Au[(Gly-Tyr-TrCys)2B], (e) Au[(Gly-Tyr-Met)2B], (f) Au[(Met)2B] and (g) Au[(TrCys)2B] in EMEM/S-; asterisk and bold letters are used to signal the most stable AuNP.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3716793&req=5

Figure 10: Optical microscope images of the morphology of Hep G2 cells. (a) untreated (b) after 24-h incubation with chloramine-T (positive control) and after 24-h exposure to AuNP preparations (c) Au[(Gly-Trp-Met)2B], (d) Au[(Gly-Tyr-TrCys)2B], (e) Au[(Gly-Tyr-Met)2B], (f) Au[(Met)2B] and (g) Au[(TrCys)2B] in EMEM/S-; asterisk and bold letters are used to signal the most stable AuNP.
Mentions: An optical microscope was used to view the cells and NPs in EMEM/S- at various time points throughout the exposure. The study was performed only for exposures using EMEM/S- because of evidence of higher instability and toxicity of AuNPs under these conditions. Figure 10 shows Hep G2 cells after 24 h of incubation with NP concentrations of 100 μg/ml. The AuNPs Au[(Met)2B] formed large agglomerates that covered almost the entire well (Figure 10f). While this phenomenon made it difficult to view the cells, evidence of cell rounding was observed when compared to the untreated cells (Figure 10a). However, the cells most dramatically affected were those exposed to Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B] (Figure 10d,g, respectively). Unique and distinct dark assemblages in the cells exposed to Au[(Gly-Tyr-TrCys)2B] (Figure 10d) were evident. The size of Au[(Gly-Tyr-TrCys)2B] agglomerates did not permit NP visualisation in a cell-free Au[(Gly-Tyr-TrCys)2B] suspension (Figure 8). This observation led us to believe that the assemblies, visible when Au[(Gly-Tyr-TrCys)2B] was in contact with cells (Figure 10d), are a result of cell damage or are formed from cellular interaction with these AuNPs. The cells exposed to Au[(TrCys)2B] (Figure 10g) showed the characteristic appearance of cells treated with chloramine-T (Figure 10b), the chemical used in this study as a positive control. The cells rounded completely into a blister-like structure. However, the AuNPs did not appear to interact with the cells and instead were suspended in the medium. The morphology of Hep G2 cells incubated with Au[(Gly-Trp-Met)2B] was comparable with that of untreated cells, despite the presence of some dark assemblages (Figure 10c). Cells exposed to Au[(Gly-Tyr-Met)2B] (Figure 10e) also seemed to retain healthy cellular features, with NPs settled on clear areas of the 96-well plate, thereby suggesting limited NP-cellular interaction.

Bottom Line: Moreover, these AuNPs have unique biological effects on Hep G2 cells while showing low toxicity.The production of ROS along with supporting optical microscopy images suggests cellular interaction/uptake of these particular AuNPs.Future research efforts should further test this hypothesis, as such interaction/uptake is highly relevant in drug delivery systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departamento de Medio Ambiente, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de la Coruña Km 7,5, Madrid 28040, Spain. yolanda.cortes@urjc.es.

ABSTRACT
In this study, we explored the biocompatibility of Au nanoparticles (NPs) capped with peptide-biphenyl hybrid (PBH) ligands containing glycine (Gly), cysteine (Cys), tyrosine (Tyr), tryptophan (Trp) and methionine (Met) amino acids in the human hepatocellular carcinoma cell line Hep G2. Five AuNPs, Au[(Gly-Tyr-Met)2B], Au[(Gly-Trp-Met)2B], Au[(Met)2B], Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B], were synthesised. Physico-chemical and cytotoxic properties were thoroughly studied. Transmission electron micrographs showed isolated near-spherical nanoparticles with diameters of 1.5, 1.6, 2.3, 1.8 and 2.3 nm, respectively. Dynamic light scattering evidenced the high stability of suspensions in Milli-Q water and culture medium, particularly when supplemented with serum, showing in all cases a tendency to form agglomerates with diameters approximately 200 nm. In the cytotoxicity studies, interference caused by AuNPs with some typical cytotoxicity assays was demonstrated; thus, only data obtained from the resazurin based assay were used. After 48-h incubation, only concentrations ≥50 μg/ml exhibited cytotoxicity. Such doses were also responsible for an increase in reactive oxygen species (ROS). Some differences were observed among the studied NPs. Of particular importance is the AuNPs capped with the PBH ligand (Gly-Tyr-TrCys)2B showing remarkable stability in culture medium, even in the absence of serum. Moreover, these AuNPs have unique biological effects on Hep G2 cells while showing low toxicity. The production of ROS along with supporting optical microscopy images suggests cellular interaction/uptake of these particular AuNPs. Future research efforts should further test this hypothesis, as such interaction/uptake is highly relevant in drug delivery systems.

No MeSH data available.


Related in: MedlinePlus