Magnetically-driven 2D cells organization on superparamagnetic micromagnets fabricated by laser direct writing

Abstract

We demonstrate a proof of concept for magnetically-driven 2D cells organization on superparamagnetic micromagnets fabricated by laser direct writing via two photon polymerization (LDW via TPP) of a photopolymerizable superparamagnetic composite. The composite consisted of a commercially available, biocompatible photopolymer (Ormocore) mixed with 4 mg/mL superparamagnetic nanoparticles (MNPs). The micromagnets were designed in the shape of squares with 70 µm lateral dimension. To minimize the role of topographical cues on the cellular attachment, we fabricated 2D microarrays similar with a chessboard: the superparamagnetic micromagnets alternated with non-magnetic areas of identical shape and lateral size as the micromagnets, made from Ormocore by LDW via TPP. The height difference between the superparamagnetic and non-magnetic areas was of ~ 6 µm. In the absence of a static magnetic field, MNPs-free fibroblasts attached uniformly on the entire 2D microarray, with no preference for the superparamagnetic or non-magnetic areas. Under a static magnetic field of 1.3 T, the fibroblasts attached exclusively on the superparamagnetic micromagnets, resulting a precise 2D cell organization on the chessboard-like microarray. The described method has significant potential for fabricating biocompatible micromagnets with well-defined geometries for building skin grafts adapted for optimum tissue integration, starting from single cell manipulation up to the engineering of whole tissues.

Iron Oxide Nanoparticles in Regenerative Medicine and Tissue Engineering

“…In vitro cell culture with murine NIH 3T3 fibroblasts showed that the composite fibers not only exhibited low cytotoxicity, but also provided a suitable scaffold for cell adhesion and may potentially be used for skin tissue engineering. Paun et al demonstrated a proof of concept of magnetically driven 2D cell organization on superparamagnetic micromagnets fabricated by laser direct writing by two-photon polymerization of a photopolymerizable superparamagnetic composite [ 619 ]. Under a static magnetic field, fibroblasts adhered exclusively to the micromagnets, resulting in precise 2D cell organization on the chessboard-like microarray, suggesting a potential suitability skin tissue engineering.…”

Recent Advances on Nanocomposite Resists With Design Functionality for Lithographic Microfabrication

“…Superparamagnetic NPs have also been added to microstrucured surfaces for applications in bioscience. Paun et al used 5 nm maghemite (γ-Fe 2 O 3 ) NPs as NFs added to the commercial photo-polymer Ormocore (Paun et al, 2019;Paun et al, 2020). Films of the NCPR were submitted to DLW through TPL to pattern 3D scaffolds or surfaces where cell cultures were grown.…”

“…This was attributed to an interplay of topological (i.e., extra roughness due to presence of BTNPs) and piezoelectric phenomena (Marino et al, 2015b). Scaffolds have also been fabricated through TPL of superparamagnetic NCPRs (Paun et al, 2019;Paun et al, 2020). Several works in this direction do not employ NCPRs but are nevertheless interesting (Klein et al, 2011;Rasoulianboroujeni et al, 2019;Yu et al, 2019a;Yang et al, 2020c).…”

In Vitro Magnetic Techniques for Investigating Cancer Progression

“…When the substrate was not exposed to a magnetic field, seeded fibroblasts spread throughout both areas in a traditional monolayer. However, when a static magnetic field was produced using permanent magnets underneath the device, the fibroblasts were only observed on the squares with magnetic nanoparticles, demonstrating a proof-of-concept patterning of cells into specific culture areas [99]. Fu et al similarly magnetized polyethylene glycol-diacrylate and used it as a removable block to pattern cells into specific shapes.…”