Using intracellular plasmonics to characterize nanomorphology in human cells

Abstract

Determining the characteristics and localization of nanoparticles inside cells is crucial for nanomedicine design for cancer therapy. Hyperspectral imaging is a fast, straightforward, reliable, and accurate method to study the interactions of nanoparticles and intracellular components. With a hyperspectral image, we could collect spectral information consisting of thousands of pixels in a short time. Using hyperspectral images, in this work, we developed a label-free technique to detect nanoparticles in different regions of the cell. This technique is based on plasmonic shifts taking place during the interaction of nanoparticles with the surrounding medium. The unique optical properties of gold nanoparticles, localized surface plasmon resonance bands, are influenced by their microenvironment. The LSPR properties of nanoparticles, hence, could provide information on regions in which nanoparticles are distributed. To examine the potential of this technique for intracellular detection, we used three different types of gold nanoparticles: nanospheres, nanostars and Swarna Bhasma (SB), an Indian Ayurvedic/Sidha medicine, in A549 (human non-small cell lung cancer) and HepG2 (human hepatocellular carcinoma) cells. All three types of particles exhibited broader and longer bands once they were inside cells; however, their plasmonic shifts could change depending on the size and morphology of particles. This technique, along with dark-field images, revealed the uniform distribution of nanospheres in cells and could provide more accurate information on their intracellular microenvironment compared to the other particles. The region-dependent optical responses of nanoparticles in cells highlight the potential application of this technique for subcellular diagnosis when particles with proper size and morphology are chosen to reflect the microenvironment effects properly.

Near-Infrared Photoactive Theragnostic Gold Nanoflowers for Photoacoustic Imaging and Hyperthermia

“…The intracellular plasmonic literature shows a shift dependence of the LSPR Au-based NP band and its subcellular compartment localization. Some studies revealed a band shift of almost 40 nm once they were inside or outside cells . Although this intracellular plasmonic effect probably did not alter the PTT property of our AuNF because of their broad NIR band, as observed in PTT results.…”

Gold Nano-Bio-Interaction to Modulate Mechanobiological Responses for Cancer Therapy Applications

“…Different responses to nanostars and nanospheres could be associated with different distributions of nanospheres and nanostars in cells. According to the results and our previous study, nanospheres were localized mainly at the periphery of the nucleus where the force is generated and needs to translocate to the adhesion complexes for cell migration, so they could profoundly reduce cell migration compared to nanostars. Different affinities to different subcellular elements may also be an influential factor in the level of impact on mechanobiological properties.…”

“…A549 cells appeared to uptake more nanospheres than nanostars over 24 h, likely due to their relatively smaller size. Our previous study shows that A549 cells take up more nanospheres compared to nanostars …”

“…Our previous study explained thoroughly how hyperspectral images could be used for intracellular diagnosis of NPs and to identify them in or out of cells. , Changes in the LSPR band of gold NPs (with the help of hyperspectral images) can be used to confirm their presence and localization in cells. The properties of solutions can influence the energy associated with electric field oscillation, altering the LSPR band.…”

Nanomaterials in Animal Husbandry: Research and Prospects

“…Compared with non-spherical counterparts, spherical NPs have a higher level of internalization ( Sohrabi Kashani et al, 2020 ). Even though nanospheres are promising candidates for drug delivery, anisotropic nanostructures may be more efficient due to larger surface/volume ratios and the ability to deliver higher drug concentrations to the desired regions ( Sun et al, 2014 ).…”