Gold Nanoparticles
Gold nanoparticles are considered to be an important platform for pharmaceutical and biomedical applications. This is due to their physicochemical properties. The inert core does not produce any cytotoxicity. Gold nanoparticles absorb and scatter under
Figure 8.9 Subcellular localization of single quantum dots (QDs). Polyethylene glycol—QDs were conjugated to localization peptides, which allow active targeting to nucleus (A) and mitochondria (B). These nanoconstructs were delivered to 3T3 fibroblast cells via microinjection. (C) Quantum dots remain fluorescent even after 8 min of mercury lamp exposure. (D) Conventional mitotracker dye photo bleaches at similar exposure. (Published with permission from John Wiley and Sons.)
![Properties and potential applications of gold nanoparticles in biology and medicine [73]](/htm/img/39/532/89.png)
Figure 8.10 Properties and potential applications of gold nanoparticles in biology and medicine [73].
Table 8.1 Comparison of gold nanoparticles subcellular localization using different methods of cellular delivery [73]
|
Method |
Gold core size (nm) |
Capping |
Subcellular localization |
Toxicity |
References |
|
CPP |
16 |
94% PEG, 2% Tat, 2% NLS, 2% penetratin |
Cytoplasmic and nuclear |
Not reported |
[14] |
|
CPP |
~20 |
Nuclear localization sequence and receptor-mediated endocytosis peptides |
Nucleus |
~5% death |
[74] |
|
CPP |
12 |
Sweet arrow peptide |
Endosomal |
Not reported |
[71] |
|
CPP |
2.8 |
Tat peptide |
Cytosolic around the mitochondria and in nucleus |
Low cytotoxicity below 10 pM |
[67,70] |
|
CPP |
20 |
BiotinylatedTat- HA2, PEG-SH, antiactin antibodies |
Cytoskeleton (cytoplasm) |
Not reported |
[75] |
|
PEI |
4 |
PEI |
Mainly endosomal and some nuclear localization |
20-30% death |
[76] |
|
SLO toxin |
5 and 10 |
90% CALNN-10% CALNN-PEG |
Endosomal and cytosolic |
Toxicity controlled by protocol optimization |
Shaheen et al., unpublished data |
|
Liposomes |
1.4 |
Phospholipid |
Lysosomes near the nuclear membrane |
Not reported |
[77] |
|
Transferrin |
14-100 |
Transferrin |
Endosomal |
Nontoxic |
[56,78] |
|
Ultrasound |
100 |
DDPE |
Endosomal |
Nontoxic |
[79] |
|
Microinjection |
11-32 |
Nucleoplasms |
Nuclear and cytoplasmic |
Not reported |
[80] |
CPP, cell-penetrating peptide; NLS, nuclear localization signal; PEG, polyethylene glycol.
resonance light both at the visible and near-infrared spectrum [71]. The plasmon resonance of these bands can be optimized over a wide spectral range. It is done by modification of parameters such as component of the particles, size, and shape [72]. Light scattering property ofgold nanoparticle is strong enough to be easily detected. The signal is stronger than most fluorophores and like quantum dots does not undergo photobleach- ing [73]. For nanoparticles below 30 nm, light absorption is more than its scattering. This phenomenon can be utilized for imaging by photothermal microscopy. It can also be easily imaged by transmission as well as scanning electron microscopy. Hence gold nanoparticles are better suited to study mechanism and kinetics of particle movement across the nucleopore complex [73].
The potential applications of gold nanoparticles include but are not limited to bioimaging, single molecule tracking, biosensing, drug delivery, transfection, and diagnosis. Bioconjugation of relevant ligands to gold nanoparticle leads to specific targeting of tumor cells with minimal uptake into normal cells. It has the potential to provide efficient diagnostic and therapeutic strategies in neoplastic disorders. Fig. 8.10 depicts the different significant applications of gold nanoparticles. Table 8.1 depicts different subcellular localization of gold nanoparticles when conjugated with various ligands.
