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Background: Cell penetrating peptides (CPPs) can enter a cell through the cell membrane, and used in the fields of drug delivery, gene therapy, and cancer therapy by their property transporting various molecules into cytoplasm. Gold nanospheres (GNSs) are a useful tool for molecular imaging, because they are not cytotoxic and have high solubility, excellent light scattering property and ease of synthesis. We constructed a drug delivery system by developing gold nanospheres conjugated to MCaUF1-9-C, a CPP derived from maurocalcine (MCa) scorpion toxin. We examined the applicability of this cell-selective anti-cancer drug delivery system by evaluating its cell-penetrating and cell death activities. Methods: Cell viability of HeLa and MDA-MB-231 cells, against 500 nanomolar concentration of doxorubicin (DOX)-conjugated gold nanoparticles (DOX-GNPs, and DOX-MCaUF1–9-C-GNP) were evaluated using MTT assay. Cell penetrability of MCaUF1-9-C peptide conjugated to gold nanoparticles investigated using of dark field imaging and atomic absorption spectroscopy (AAS). Results: HeLa cell viability was about 87% when treated with DOX-GNP and DOX-MCaUF1-9-C-GNP, whereas DOX-MCaUF1–9-C-GNP induced high cytotoxicity in MDA-MB-231 cells (30%). Dark field imaging demonstrated higher affinity of MCaUF1–9-C-GNP for the MDA-MB-231 cell compared with HeLa cells. Moreover, atomic absorption spectrometry data analysis showed that 33% of the total amounts of the applied MCaUF1–9-C-GNP were internalized in MDA-MB-231 cells. Conclusion: These results demonstrated that peptide conjugated GNP would be a useful tool for the development of a cell-selective drug delivery system.

Background: Reduced toxicity and ease of modification make gold nanoparticles (GNPs) suitable for targeted delivery and bioimaging via conjugating cell-penetrating peptides (CPPs). This study aimed to assess the enhanced penetration of gold nanoparticles into cells via using TAT peptide as a cell-penetrating peptide. Methods: Gold nanoparticles and TAT-conjugated gold nanoparticles (TAT-C-GNP) were characterized using ultraviolet-visible spectrophotometry, dynamic light scattering, zeta potential method, and transmission electron microscopy. The cytotoxicity effects of nanoparticles on HeLa, and A431 cell lines were studied. Uptake of TAT-conjugated gold nanoparticles was tested in cells, using dark field microscopy. Findings: Gold nanoparticles and TAT-conjugated gold nanoparticles had little to no effect on cell viability. Upon exposure to gold nanoparticles, TAT-conjugated gold nanoparticles displayed higher uptake than gold nanoparticles in A431 cell line; whereas none of the nanoparticles showed penetration in HeLa cell. Conclusion: Thus, TAT-conjugated gold nanoparticles have enhanced cellular internalization and are suitable for various biomedical applications as nanoconjugates.

Background and aims: Recently, in addition to numerous molecular methods available for diagnosis, methods based on the design of various biosensors considered. Some of these biosensors are Lateral flow tests based on gold nanoparticles. Considering the importance of the application of gold nanoparticles as markers in biosensors and also the need for the use of sugars in the construction of biosensors, this study was aimed to investigate the effects of various sugars (monosaccharides and disaccharides) on gold nanoparticles for the development of diagnostic biosensors. Methods: In this experimental study, after synthesis of gold nanoparticles chemically, by size, assessed maximum absorption at 520 nm, and concentration of nanoparticles by spectrophotometer and DLS method. Then, considering the importance of using sugars in the manufacture of biosensors, a concentration gradient of 5 to 500 mM glucose, fructose, sucrose, and trehalose, and their absorption spectra, after exposure to gold nanoparticles at 450 to 700 nm was detected. Results: The results of the spectrophotometric spectrum of synthesized nanoparticles in the presence and absence of sugars of monosaccharide and disaccharide indicate a decrease in the maximum absorption of nanoparticles after the application of a steady slope of sugar types on them and also concentration gradient of glucose, sucrose and trehalose sugars had no effect on the accumulation and aggregation of gold nanoparticles, while fructose at concentrations up to 50 mM leads to the accumulation of gold nanoparticles. Conclusion: Due to the necessity of using sugars in the production of bionanosensors, it seems that the use of ketone sugars, such as fructose, at concentrations of 50 mM upwards is not suitable for making biosensors. [ABSTRACT FROM AUTHOR]