Development of multilayered cell‐hydrogel composites using an acoustic focusing technique

Abstract

Multi-layered composites composed of mammalian cells arranged in a hydrogel have been prepared using an acoustic focusing technique. Acoustic focusing is a simple, non-chemical technique that allows for the fast arrangement of cells in matrices where the control of cell geometry is beneficial. Breast cancer cells (MDA-MB231), were dispersed in a 30 wt % solution of poly(ethylene glycol) diacrylate (PEGDA) of molecular weight 400 at a density of 5 × 10 6 cells per ml of PEGDA solution. An ultrasonic field was used to organize the cells into multiple layers prior to polymerization of PEGDA. Disk-shaped hydrogel composites, typically 1 cm in diameter and 2 mm thick were prepared based on a PEGDA solution volume of 130 uL. At an acoustic frequency of 2.32 MHz, composites were fabricated, where concentric rings/layers of cells were interspersed with cell-free hydrogel. The cells were located in annuli approximately 80 μm thick and about 300 μm apart. The structure and viability of the cells within these constructs were studied using a fluorescent LIVE/DEAD assay. The viability of the cells was on the order of 50%. Cell death was primarily attributed to exposure of cells to the PEGDA solution prior to polymerization, rather than adverse effects of polymerization or the sound field itself.

Two-dimensional single-cell patterning with one cell per well driven by surface acoustic waves

“…While this is sufficient for many long-term cell culture studies, for other applications such as the trapping and analysis of rare cells it is desirable to dictate both the time and duration of capture in addition to the location of cell trapping. A number of active techniques have been used for particle and cell manipulation and patterning, including optical 14 15 , magnetic 16 , electrical 17 and acoustic 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 forces, although these differ in their suitability to the patterning of individual, isolated cells. High-frequency acoustic forces—where periodically fluctuating pressure conditions result in time-averaged forces that push suspended matter towards acoustic nodes/antinodes—are generally biocompatible and have demonstrated potential for long-term cell observation 22 .…”

Ultrasound assisted particle and cell manipulation on-chip

“…They later used this technique to organise endothelial cells so as to form a vascular-like bed within the matrix [93]. Mazzoccoli et al also worked in hydrogels to form concentric cylindrical arrangements of a breast cancer cell line (MDA-MB231) [94].…”

Acoustophoretic Control of Microparticle Transport Using Dual-Wavelength Surface Acoustic Wave Devices

“…Pure and controllable acoustic forces involved in the acoustic manipulation method produce little or no damage to the viability and functionality of biological cells [7]. A trend in acoustic manipulation methods involves creating a standing acoustic-wave field across a microfluidic channel and employing the resulting acoustic pressure field to transport, trap, separate, pattern or sort microparticles or bio-cells suspended in microfluids [8,9,10,11,12,13,14,15]. Various types of acoustic-wave modes have been utilized to produce the desired acoustic pressure fields, including ultrasonic bulk acoustic waves (BAWs) [16,17,18,19,20,21], surface acoustic waves (SAWs) [22,23,24,25,26,27,28,29,30] and Lamb waves (LWs) [31,32,33].…”