Using intracellular plasmonics to characterize nanomorphology in human cells

Hot-Electron Dynamics Mediated Medical Diagnosis and Therapy

Surface plasmon resonance excitation significantly enhances the absorption of light and increases the generation of "hot" electrons, i.e., conducting electrons that are raised from their steady states to excited states. These excited electrons rapidly decay and equilibrate via radiative and nonradiative damping over several hundred femtoseconds. During the hot-electron dynamics, from their generation to the ultimate nonradiative decay, the electromagnetic field enhancement, hot electron density increase, and local heating effect are sequentially induced. Over the past decade, these physical phenomena have attracted considerable attention in the biomedical field, e.g., the rapid and accurate identification of biomolecules, precise synthesis and release of drugs, and elimination of tumors. This review highlights the recent developments in the application of hot-electron dynamics in medical diagnosis and therapy, particularly fully integrated device techniques with good application prospects. In addition, we discuss the latest experimental and theoretical studies of underlying mechanisms. From a practical standpoint, the pioneering modeling analyses and quantitative measurements in the extreme near field are summarized to illustrate the quantification of hot-electron dynamics. Finally, the prospects and remaining challenges associated with biomedical engineering based on hot-electron dynamics are presented.

Method for nanoparticles uptake evaluation based on double labeled fluorescent cells scanned in enhanced darkfield microscopy

We present a method that integrates the standard imaging tools for locating and detecting unlabeled nanoparticles (NPs) with computational tools for partitioning cell volumes and NPs counting within specified regions to evaluate their internal traffic. The method uses enhanced dark field CytoViva optical system and combines 3D reconstructions of double fluorescently labeled cells with hyperspectral images. The method allows the partitioning of each cell image into four regions: nucleus, cytoplasm, and two neighboring shells, as well as investigations across thin layers adjacent to the plasma membrane. MATLAB scripts were developed to process the images and to localize NPs in each region. Specific parameters were computed to assess the uptake efficiency: regional densities of NPs, flow densities, relative accumulation indices, and uptake ratios. The results of the method are in line with biochemical analyses. It was shown that a sort of saturation limit for intracellular NPs density is reached at high extracellular NPs concentrations. Higher NPs densities were found in the proximity of the plasma membranes. A decrease of the cell viability with increasing extracellular NPs concentration was observed and explained the negative correlation of the cell eccentricity with NPs number.

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

In the present study, we investigate the mechanobiological responses of human lung cancer that may occur through their interactions with two different types of gold nanoparticles: nanostars and nanospheres. Hyperspectral images of nanoparticle-treated cells revealed different spatial distributions of nanoparticles in cells depending on their morphology, with nanospheres being more uniformly distributed in cells than nanostars. Gold nanospheres were also found to be more effective in mechanobiological modulations. They significantly suppressed the migratory ability of cells under different incubation times while lowering the bulk stiffness and adhesion of cells. This in vitro study suggests the potential applications of gold nanoparticles to manage cell migration. Nano-bio-interactions appeared to impact the cytoskeletal organization of cells and consequently alter the mechanical properties of cells, which could influence the cellular functions of cells. According to the results and migratory index model, it is thought that nanoparticle-treated cells experience mechanical changes in their body, which largely reduces their migratory potentials. These findings provide a better understanding of nano-bio-interaction in terms of cell mechanics and highlight the importance of mechanobiological responses in designing gold nanoparticles for cancer therapy.

Nanomaterials in Animal Husbandry: Research and Prospects

Anti-inflammatory, antiviral, and anti-cancer treatments are potential applications of nanomaterials in biology. To explore the latest discoveries in nanotechnology, we reviewed the published literature, focusing on co-assembled nanoparticles for anti-inflammatory and anti-tumor properties, and their applications in animal husbandry. The results show that nanoparticles have significant anti-inflammation and anti-tumor effects, demonstrating broad application prospects in animal breeding. Furthermore, pooled evidence suggests that the mechanism is to have a positive impact on inflammation and tumors through the specific drug loading by indirectly or directly targeting the disease sites. Because the precise regulatory mechanism remains unclear, most studies have focused on regulating particular sites or even specific genes in the nucleus by targeting functional co-assembled nanoparticles. Hence, despite the intriguing scenarios for nanotechnology in farmed animals, most results cannot yet be translated into field applications. Overall, nanomaterials outperformed similar materials in terms of anti-inflammatory and anti-tumor. Nanotechnology also has promising applications in animal husbandry and veterinary care, and its application and development in animal husbandry remain an exciting area of research.

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

Branched anisotropic gold nanostructures present distinguished performance acting both as contrast agents for photoacoustic imaging and as active agents for photothermal therapies. Despite advances in their fabrication methods, the synthesis of such gold nanomaterials in a simple and reproducible way is still a challenge. In this paper, we report the development of branched anisotropic gold nanoparticles, the so-called gold nanoflowers (AuNFs), as near-infrared active theragnostic materials for cancer therapy and diagnosis. In situ chemical synthesis of the AuNFs was optimized to obtain monodisperse nanoflowers with controllable size and optical properties. Upon varying the temperature and gold ion concentrations, it was possible to tune the optical activity of the nanoparticles from 590 to 960 nm. The AuNFs exhibited good stability in the cell culture medium, and under laser irradiation. Photoacoustic imaging revealed that the NFs could be imaged in phantom systems even at low concentrations. In vitro tests revealed that the nanoflowers were effective in the photothermal therapy of a rat hepatocarcinoma (HTC) cell lineage. In addition, no toxicity was observed to mouse fibroblast (FC3H) cells incubated with the AuNFs. Our results reveal a simple method to synthesize branched anisotropic gold nanostructures, which is a promising platform for photothermal and photoacoustic therapies.

Cancer-Nano-Interaction: From Cellular Uptake to Mechanobiological Responses

With the advancement of nanotechnology, the nano-bio-interaction field has emerged. It is essential to enhance our understanding of nano-bio-interaction in different aspects to design nanomedicines and improve their efficacy for therapeutic and diagnostic applications. Many researchers have extensively studied the toxicological responses of cancer cells to nano-bio-interaction, while their mechanobiological responses have been less investigated. The mechanobiological properties of cells such as elasticity and adhesion play vital roles in cellular functions and cancer progression. Many studies have noticed the impacts of cellular uptake on the structural organization of cells and, in return, the mechanobiology of human cells. Mechanobiological changes induced by the interactions of nanomaterials and cells could alter cellular functions and influence cancer progression. Hence, in addition to biological responses, the possible mechanobiological responses of treated cells should be monitored as a standard methodology to evaluate the efficiency of nanomedicines. Studying the cancer-nano-interaction in the context of cell mechanics takes our knowledge one step closer to designing safe and intelligent nanomedicines. In this review, we briefly discuss how the characteristic properties of nanoparticles influence cellular uptake. Then, we provide insight into the mechanobiological responses that may occur during the nano-bio-interactions, and finally, the important measurement techniques for the mechanobiological characterizations of cells are summarized and compared. Understanding the unknown mechanobiological responses to nano-bio-interaction will help with developing the application of nanoparticles to modulate cell mechanics for controlling cancer progression.

DMD-based hyperspectral microscopy with flexible multiline parallel scanning

As one of the most common hyperspectral microscopy (HSM) techniques, line-scanning HSM is currently utilized in many fields. However, its scanning efficiency is still considered to be inadequate since many biological and chemical processes occur too rapidly to be captured. Accordingly, in this work, a digital micromirror device (DMD) based on microelectromechanical systems (MEMS) is utilized to demonstrate a flexible multiline scanning HSM system. To the best of our knowledge, this is the first line-scanning HSM system in which the number of scanning lines N can be tuned by simply changing the DMD's parallel scanning units according to diverse applications. This brilliant strategy of effortless adjustability relies only on on-chip scanning methods and totally exploits the benefits of parallelization, aiming to achieve nearly an N-time improvement in the detection efficiency and an N-time decrease in the scanning time and data volume compared with the single-line method under the same operating conditions. To validate this, we selected a few samples of different spectral wavebands to perform reflection imaging, transmission imaging, and fluorescence imaging with varying numbers of scanning lines. The results show the great potential of our DMD-based HSM system for the rapid development of cellular biology, material analysis, and so on. In addition, its on-chip scanning process eliminates the inherent microscopic architecture, making the whole system compact, lightweight, portable, and not subject to site constraints.