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Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro

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ABSTRACT

Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material.

No MeSH data available.


Ag-NP effects on purified cathepsin B and L enzymes. Ag-NPs were incubated with purified cathepsin B (a) or L (b) enzymes. The amount of cathepsin activity in the treatment groups is expressed as percent control and plotted as the mean +/- SEM. Fluorescence was determined using a fluorescent plate reader (*P < 0.05, n = 6).
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Figure 4: Ag-NP effects on purified cathepsin B and L enzymes. Ag-NPs were incubated with purified cathepsin B (a) or L (b) enzymes. The amount of cathepsin activity in the treatment groups is expressed as percent control and plotted as the mean +/- SEM. Fluorescence was determined using a fluorescent plate reader (*P < 0.05, n = 6).

Mentions: To determine whether the Ag-NPs were influencing the cell signaling or the enzyme directly, the Ag-NPs were also incubated with purified cathepsin B or L, which were then assayed for activity. A significant decrease was seen in the activity of the purified cathepsin B enzyme with the 10-nm Ag-NPs at 10 μg/ml and even greater at 50 μg/ml, regardless of the presence or absence of the PS coating (Figure 4a). The 25-nm uncoated Ag-NPs had little effect on cathepsin B activity at 10 μg/ml, but exhibited similar affects as the 10-nm particles at a dose of 50 μg/ml (Figure 4a). The 25-nm PS-Ag displayed a similar effect as the 25-nm uncoated Ag-NP, with no effect at 10 μg/ml and a significant decrease in cathepsin B activity at 50 μg/ml, however, the decrease with this particle was much less than that with the uncoated 25-nm Ag-NP (Figure 4a). When the purified cathepsin L enzyme was treated with Ag-NPs, the effect on activity was also much more significant than the effect on purified cathepsin B (Figure 4). All four Ag-NPs tested caused a significant decrease in cathepsin L activity at both the 10 and 50 μg/ml doses, with the 10-nm Ag-NPs (uncoated and PS-coated) causing a more pronounced effect (Figure 4b).


Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro
Ag-NP effects on purified cathepsin B and L enzymes. Ag-NPs were incubated with purified cathepsin B (a) or L (b) enzymes. The amount of cathepsin activity in the treatment groups is expressed as percent control and plotted as the mean +/- SEM. Fluorescence was determined using a fluorescent plate reader (*P < 0.05, n = 6).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211222&req=5

Figure 4: Ag-NP effects on purified cathepsin B and L enzymes. Ag-NPs were incubated with purified cathepsin B (a) or L (b) enzymes. The amount of cathepsin activity in the treatment groups is expressed as percent control and plotted as the mean +/- SEM. Fluorescence was determined using a fluorescent plate reader (*P < 0.05, n = 6).
Mentions: To determine whether the Ag-NPs were influencing the cell signaling or the enzyme directly, the Ag-NPs were also incubated with purified cathepsin B or L, which were then assayed for activity. A significant decrease was seen in the activity of the purified cathepsin B enzyme with the 10-nm Ag-NPs at 10 μg/ml and even greater at 50 μg/ml, regardless of the presence or absence of the PS coating (Figure 4a). The 25-nm uncoated Ag-NPs had little effect on cathepsin B activity at 10 μg/ml, but exhibited similar affects as the 10-nm particles at a dose of 50 μg/ml (Figure 4a). The 25-nm PS-Ag displayed a similar effect as the 25-nm uncoated Ag-NP, with no effect at 10 μg/ml and a significant decrease in cathepsin B activity at 50 μg/ml, however, the decrease with this particle was much less than that with the uncoated 25-nm Ag-NP (Figure 4a). When the purified cathepsin L enzyme was treated with Ag-NPs, the effect on activity was also much more significant than the effect on purified cathepsin B (Figure 4). All four Ag-NPs tested caused a significant decrease in cathepsin L activity at both the 10 and 50 μg/ml doses, with the 10-nm Ag-NPs (uncoated and PS-coated) causing a more pronounced effect (Figure 4b).

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material.

No MeSH data available.