Extracellular matrix (ECM) stiffness is correlated to malignancy and invasiveness of cancer cells. Although the mechanism of change is unclear, mechanical signals from the ECM may affect physical properties of cells such as their density profile. The current methods, such as Percoll density‐gradient centrifugation, are unable to detect minute density differences. A magnetic levitation device is developed (i.e., MagDense platform) where cells are levitated in a magnetic gradient allowing them to equilibrate to a levitation height that corresponds to their unique cellular density. In application of this system, MDA‐MB‐231 breast and A549 lung cancer cells are cultured and overall differences in cell density are observed in response to increasing collagen fiber density. Overall, density values are significantly more spread out for MDA‐MB‐231 cells extracted from the 1.44 mg mL−1 collagen gels compared to those from 0.72 mg mL−1 collagen, whereas no significant difference with A549 cell lines is observed. The MagDense platform can determine differences in cellular densities under various microenvironmental conditions. The imaging of cancer cells in a magnetic levitation device serves as a unique tool to observe changes in phenotypic properties of cancer cells as they relate to micromechanical cues encoded by the ECM.

The cornea is critical for vision, and corneal healing after trauma is fundamental in maintaining its transparency and function. Through the study of corneal injury models, researchers aim to enhance their understanding of how the cornea heals and develop strategies to prevent and manage corneal opacities. Chemical injury is one of the most popular injury models that has extensively been studied on mice.Most previous investigators have used a flat paper soaked in sodium hydroxide to induce corneal injury. However, inducing corneal and limbal injury using flat filter paper is unreliable, since the mouse cornea is highly curved. Here, we present a new instrument, a modified biopsy punch, that enables the researchers to create a well-circumscribed, localized, and evenly distributed alkali injury to the murine cornea and limbus. This punch-trephine method enables researchers to induce an accurate and reproducible chemical burn to the entire murine cornea and limbus while leaving other structures, such as the eyelids, unaffected by the chemical. Moreover, this study introduces an enucleation technique that preserves the medial caruncle as a landmark for identifying the nasal side of the globe. The bulbar and palpebral conjunctiva, and lacrimal gland are also kept intact using this technique. Ophthalmologic examinations were performed via slit lamp biomicroscope and fluorescein staining on days 0, 1, 2, 6, 8, and 14 post-injury. Clinical, histological, and immunohistochemical findings confirmed limbal stem cell deficiency and ocular surface regeneration failure in all experimental mice. The presented alkali corneal injury model is ideal for studying limbal stem cell deficiency, corneal inflammation, and fibrosis. This method is also suitable for investigating pre-clinical and clinical efficacies of topical ophthalmologic medications on the murine corneal surface.

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