In an article recently published in the open-access MDPI journal nanomaterials, researchers investigated the mechanism of interaction between nanoscale materials and specific cells for biomedical applications, primarily related to targeted delivery and tracing.
Here, the localization, cellular uptake quantity, and response time of gold nanorods in MCF-7 and SKBR-3 breast cancer cells were measured.
The amalgamation of biotechnology and nanotechnology has been a quite fascinating field of research for the last few years.
Currently, nanomaterials are extensively used in biomedical applications such as drug delivery, magnetic or fluorescent bio-imaging, tissue engineering, tracing pathogens in sensitive organs, cancer chemotherapy, and many more. However, each nanomaterial interacts differently with a particular type of cell.
Many studies have shown cellular uptake of gold nanorods by cancer cells. MCF-7 and SKBR-3 cancer cell lines represent HER2-negative and HER2-positive breast cancer models, respectively. These cells intake gold nanorods through a mechanism occurring at the surface of the cell membrane, called endocytosis.
Inductively coupled plasma mass spectrometry (ICP-MS) can measure the efficiency of targeted delivery and cellular uptake of these nanoparticles, while transmission electron microscopy (TEM) can be used to investigate their localization.
Figure 1. Transmission electron microscope images of gold nanorods with aspect ratio around 3 at different magnifications (a–c). (d) UV–visible spectrum analysis of the prepared gold nanorods showing longitudinal and transverse plasmons around 690 nm and 514 nm, respectively. © White, B., White, M., Nima Alsudani, Z., Watanabe, F., Biris, A., Ali, N., (2022)
About the Study
In this article, researchers investigated the interaction mechanism of gold nanorods (Au NRs) in two types of breast cancer cell lines namely, MCF-7 and SKBR-3. More than 200 Au NRs with an average length and diameter of 36 and 12 nm, respectively, were synthesized using the silver ion-assisted seed-mediated method. Subsequently, MCF-7 and SKBR-3 cells were cultured in a conducive medium and allowed to bind with different concentrations of Au NRs for 1 and 2 days.
The excess Au NRs were washed away from the treated cancels using phosphate buffer saline (PBS) solution followed by treating with the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) reagent. Finally, ICP-MS and TEM analyses were performed to investigate the interaction mechanism.
Figure 2. TEM images of AuNRs in SKBR-3 cells at different time points and concentrations. SKBR-3 cells were treated with 5, 25, and 75 μg/mL of AuNRs for 1, 4, 24, and 48 h. Internalization of nanorods was observed starting at 4hourincubation with 75 μg/mL (a). After 24hourof incubation, internalization was observed with the 25 μg/mL (b) and 75 μg/mL concentrations (c). For cells incubated for 48 h, we observed internalization with 5, 25, and 75 μg/mL concentrations (d, e, and f, respectively). Red arrows point to gold nanorods localized in SKBR-3 cells. Electron photomicrographs shown are representative of at least three independent experiments with similar conditions. © White, B., White, M., Nima Alsudani, Z., Watanabe, F., Biris, A., Ali, N., (2022)
TEM images showed Au NRs had longitudinal and transverse plasmon resonances at around 680 and 514 nm, respectively. The average zeta potential of the NRs was −47.18 ± 4.26 mV. Au NRs did not show any cytotoxicity in healthy human cells. MTT methods indicated that the MCF-7 cells were less sensitive to Au NR exposure than the SKBR-3 cells for longer exposure times at higher concentrations. The SKBR-3 cells exhibited a drop in cell vitality due to higher sensitivity, whereas the MCF-7 cells had almost no drop in cell viability.
Both types of cells demonstrated a different pattern in cellular uptake of Au NRs for different exposure times and concentrations. The SKBR-3 cells had a constant cellular uptake between one to four hours, but 25 μg/mL Au NRs concentration had a higher uptake than the 75 μg/mL sample, i.e. lower concentration had a higher cellular uptake. In contrast, in MCF-7 cells, the 75 μg/mL AuNR-treated cell samples exhibited higher cellular uptake than 5 and 25 μg/mL samples, i.e. higher concentration samples had higher cellular uptake than lower concentration samples.
Furthermore, TEM analysis showed that the Au NRs interacted with the cell membrane of both cancer cells starting from one to 48 hours of exposure time. However, the Au NRs entered into the cell (i.e. internalized) for the samples with concentrations of 25 and 75 μg/mL. The 5 μg/mL concentration samples were never internalized. Moreover, the minimum exposure time for internalization was one hour and four hours for the MCF-7 and SKBR-3 cells, respectively.
The mechanism for the cellular uptake of the Au NRs was primarily micropinocytosis instead of receptor-mediated endocytosis. These Au NRs-carrying macropinosomes further interacted with the lysosomes inside the cells.
Figure 3. TEM images showing localization of gold nanorods in macropinosomes and lysosomes in both SKBR-3 and MCF-7 cell lines. AuNR localization in (a) macropinosomes (MA) and (b) lysosomes (Ly) of SKBR-3 cells. (c) Macropinosomes (MA) containing gold nanorods in MCF-7 and (d) lysosomes (Ly) containing gold nanorods in MCF-7. Red arrows point out macropinosomes and lysosomes containing gold nanorods in each image. Electron photomicrographs shown are representative of at least three independent experiments with similar conditions. © White, B., White, M., Nima Alsudani, Z., Watanabe, F., Biris, A., Ali, N., (2022)
To conclude, the researchers of this study investigated the interaction of Au NRs in two types of breast cancer cell lines, i.e. MCF-7 and SKBR-3. The shape, size, and zeta potential of Au NRs had different effects on cell vitality and toxicity of different cancer cells. Additionally, both cell types had different patterns of cellular uptake for Au NRs at different concentrations and exposure times.
The Au NRs did not enter into the cancer cells for samples with lower concentrations of NRs or lower exposure time. Also, the cellular uptake mechanism was primarily driven by micropinocytosis. These findings will help improve biomedical applications related to targeted drug delivery, tracing, and bio-imaging involving nanomaterials.
As they grow, solid tumors surround themselves with a thick, hard-to-penetrate wall of molecular defenses. Getting drugs past that barricade is notoriously difficult. Now, scientists at UT Southwestern have developed nanoparticles that can break [...]
In an article recently published in the journal Talanta, researchers demonstrated a new approach to enable the specific detection of biomarkers in human tear by employing an aptamer-based graphene affinity nanosensor. The ability to detect [...]
Selenium (Se) is an essential element found in aquatic feeds that promotes the proper development, wellbeing, and fitness of marine animals. Selenium can be transformed into nanomaterials that are more easily accessible, absorbed, and consumed by [...]
In an article recently published in the journal Nanotechnology, researchers employed a single particle imaging method for fluorescence excitation with moderate intensity to achieve spatial resolution. Here, the semiconductor nanocrystals were accessed, whose emission lifetimes [...]
Grinding is an essential manufacturing process, yet the heat due to friction associated with the process causes damage to the part being processed. Lubrication is used to reduce friction; however, traditional petroleum-based lubricants can [...]
A team of researchers from HSE University, Skoltech, MPGU, and MISIS have developed a nanophotonic-microfluidic sensor whose potential applications include cancer detection, monitoring and treatment response assessment. Today, the device can identify gases and [...]
Researchers have made a scientific breakthrough with the development of ‘nanomachines’ that can kill cancerous cells. The research team headed by Dr Youngdo Jeong from the Center for Advanced Biomolecular Recognition at the Korea Institute of Science and Technology (KIST) has engineered [...]
A novel freeze-dissolving approach has been devised that offers greater efficiency and sustainability compared to the classic freeze-drying process to make superfine powder or nanoparticles. In the research published in the journal ACS Sustainable Chemistry & Engineering, sphere-shaped [...]
Participants wanted for study on the regulation of what future AI-driven nanomedicines should look like
Would you like to help in some research on the regulation of what future AI-driven nanomedicines should look like? If so, researchers at the University of Bristol are looking for volunteers to discuss ethical [...]
In an article recently published in the journal Applied Surface Science, the researchers synthesized green fluorescent carbon dots (G-CDs) from 3,5-diaminobenzoic acid and citric acid. The as-prepared G-CDs were used to target the nucleolus and [...]
Doxorubicin (DOX) is a powerful anti-cancer medication, and efforts have been made to design nanostructures for delivering it to cancerous cells. The nanostructures increase the cytotoxic effects of DOX on cancerous cells, while reducing the negative effects [...]
A team of Brown University researchers has developed a new responsive material that is able to release encapsulated cargo only when pathogenic bacteria are present. The material could be used to make wound dressings [...]
Novel three-drug regimen used to manage life-threatening developments. In April 2021, a 42-year-old man reached out to Brian Hill, MD, PhD, for a second opinion after being diagnosed with hairy cell leukemia following a bone [...]