Interactions between Liquid Metal Droplets and Bacterial, Fungal, and Mammalian Cells

Abstract

Liquid metals (LMs) have emerged as novel materials for biomedical applications. Here, the interactions taking place between cells and LMs are reported, presenting a unique opportunity to explore and understand the LM‐biological interface. Several high‐resolution imaging techniques are used to characterize the interaction between droplets of gallium LM and bacterial, fungal, and mammalian cells. Adhesive interactions between cells and LM droplets are observed, causing deformation of the LM droplet surface, resulting in surface wrinkling and in some cases, breakage of the native oxide layer present on the LM droplet surface. In many instances, the cell wall deforms to intimately contact the LM droplets. Single‐cell force spectroscopy is performed to quantify the adhesion forces between cells and LM and characterize the nature of the adhesion. It is proposed that the flexible nature of the cell enables multiple adhesion sites with the LM droplets, imparting tensile forces on the LM droplet surface, which results in surface wrinkling on the LM droplets due to their liquid nature. Molecular dynamics simulations also suggest that flexible biomolecules on the cell surface can disrupt the Ga2O3 layer formed at the LM droplet surface. This study reveals a unique biointerfacial interaction and provides insights into the mechanisms involved.

Antibacterial Longevity of a Novel Gallium Liquid Metal/Hydroxyapatite Composite Coating Fabricated by Plasma Spray

“…Gallium has long been recognized as an efficient antibacterial agent in the treatment of infections, with in vitro and in vivo studies demonstrating a beneficial effect in intracellular and biofilm-forming bacteria. − Gallium has chemical characteristics similar to Fe, with identical ionic radii between Fe 3+ and Ga 3+ , in which biological systems respond similarly . It is critical to disrupt Fe metabolism since Fe is a key ingredient that promotes bacterial growth and functioning and the creation of biofilms .…”

Gallium-Based Liquid Metal Materials for Antimicrobial Applications

“…In addition to the physical damage caused by LMNPs to bacteria, which is commonly considered at this stage, there are also researchers who have explored the biological interactions between Ga particles and cells, aiming to further illustrate and validate the antibacterial mechanism of LMNPs. In Samuel et al’s work [ 104 ], they investigated the interactions between LM and five different cell types, including bacteria, fungi, and mammalian cells. Using super-resolution confocal laser scanning microscope (CLSM), they observed the morphological changes when cells interacted with Ga droplets in solution ( Figure 5 a) and found that there was folding wrinkle or even rupture of the oxide layer on the surface of the LM droplets after cell contact ( Figure 5 b).…”

Gallium Nanodroplets are Anti-Inflammatory without Interfering with Iron Homeostasis

“…With the progress of nanotechnology, it has become more possible to deliver and release drugs in specific sites with the assistance of nanomaterials. − In particular, recent reports have shown the peculiarity of Ga nanodroplets (GNDs) in such applications. − Gallium bulk and Ga-based alloys, in their liquid form, can be mechanically broken down into smaller submicron or nanodroplets . These droplets can interact with living cells, and they have been incorporated in biomedical applications including drug delivery, − cancer therapy, − medical imaging, , ion channel regulation, biosensing, and pathogen treatment, − by taking advantage of their properties such as low cytotoxicity and high thermal and electrical conductivities and their ability to respond to electric and magnetic fields and infrared (IR) stimulation. , In alignment with such demonstrations, here we investigate that delivering Ga, in the form of submicron or nanodroplets, into immune cells is potentially a promising strategy to modulate discrete signaling pathways, while avoiding the adverse effects of using traditional Ga 3+ . It is hypothesized that the submicron or nano sized Ga particles may be engulfed into the cells directly, without relying on the transferrin receptor (TfR).…”

“…10−13 Gallium bulk and Ga-based alloys, in their liquid form, can be mechanically broken down into smaller submicron or nanodroplets. 14 These droplets can interact with living cells, 15 and they have been incorporated in biomedical applications including drug delivery, 16−18 cancer therapy, 19−21 medical imaging, 22,23 ion channel regulation, 22 biosensing, 24 and pathogen treatment, 25−27 by taking advantage of their properties such as low cytotoxicity and high thermal and electrical conductivities and their ability to respond to electric and magnetic fields 6 and infrared (IR) stimulation. 22,28 In alignment with such demonstrations, here we investigate that delivering Ga, in the form of submicron or nanodroplets, into immune cells is potentially a promising strategy to modulate discrete signaling pathways, while avoiding the adverse effects of using traditional Ga 3+ .…”