Alginate gelation-induced cell death during laser-assisted cell printing

Abstract

Modified laser-induced forward transfer has emerged as a promising bioprinting technique. Depending on the operating conditions and cell properties, laser cell printing may cause cell injury and even death, which should be carefully elucidated for it to be a viable technology. This study has investigated the effects of alginate gelation, gelation time, alginate concentration, and laser fluence on the post-transfer cell viability of NIH 3T3 fibroblasts. Sodium alginate and calcium chloride are used as the gel precursor and gel reactant solution to form cell-laden alginate microspheres. It is found that the effects of gelation depend on the duration of gelation. Two-minute gelation is observed to increase the cell viability after 24 h incubation, mainly due to the protective cushion effect of the forming gel membrane during droplet landing. Despite the cushion effect from 10 min gelation, it is observed that the cell viability decreases after 24 h incubation because of the forming thick gel membrane that reduces nutrient and oxygen diffusion from the culture medium. In addition, the cell viability after 24 h incubation decreases as the laser fluence or alginate concentration increases.

Identification of optimal printing conditions for laser printing of alginate tubular constructs

“…It is noted that 8% alginate is way too high for cell printing. As reported (Gudapati et al, 2014), the post-printing sodium alginate concentration is significantly influenced by the sodium alginate concentration, and even when using a 3% sodium alginate solution, the resulting cell viability is barely above 50%. It is expected that the methodology developed herein applies to the process optimization of the printing of lowly concentrated alginate-cell suspensions under a sacrificial energy absorbing layer such as gelatin as well as other soft non-cellular structures.…”

Importance of Alginate Bioink for 3D Bioprinting in Tissue Engineering and Regenerative Medicine

“…In the past years, drug delivery carriers draw huge interest because of large biomacromolecules like genes and proteins as well as low-molecule weight drugs which can be delivered in a targeted or a localized manner [36,37]. Because of its biodegradable and biocompatible nature, alginate is used as a carrier for encapsulating and immobilizing drugs, cells, proteins, and bioactive molecules [38,39]. Currently, alginate-based carriers like colloidal particles, polyelectrolyte, and hydrogels are under examination; few of them are practically used.…”

Bioprinting: Uncovering the Utility Layer-By-Layer

“…For example, the heat from the laser energy may damage cells and affect their functionality if printing parameters are suboptimal [35]. Accordingly, the cell viability in LAB is generally lower when compared with inkjet or extrusionbased bioprinting [36]. Moreover, LAB is severely limited in the third dimension, which defines the height of the bioprinted construct [37].…”