Beyond 2D: effects of photobiomodulation in 3D tissue-like systems.

Polina Y Bikmulina,Yury A Rochev,Yuri M Efremov,Nastasia V Kosheleva,Vladimir I Yusupov,Anastasia I Shpichka,Peter S Timashev

doi:10.1117/1.jbo.25.4.048001

Abstract

.Significance: Currently, various scaffolds with immobilized cells are widely used in tissue engineering and regenerative medicine. However, the physiological activity and cell viability in such constructs might be impaired due to a lack of oxygen and nutrients. Photobiomodulation (PBM) is a promising method of preconditioning cells to increase their metabolic activity and to activate proliferation or differentiation.Aim: Investigation of the potential of PBM for stimulation of cell activities in hydrogels.Approach: Mesenchymal stromal cells (MSCs) isolated from human gingival mucosa were encapsulated in modified fibrin hydrogels with different thicknesses and concentrations. Constructs with cells were subjected to a single-time exposure to red (630 nm) and near-infrared (IR) (840 nm) low-intensity irradiation. After 3 days of cultivation, the viability and physiological activity of the cells were analyzed using confocal microscopy and a set of classical tests for cytotoxicity.Results: The cell viability in fibrin hydrogels depended both on the thickness of the hydrogels and the concentration of gel-forming proteins. The PBM was able to improve cell viability in hydrogels. The most pronounced effect was achieved with near-IR irradiation at the 840-nm wavelength.Conclusions: PBM using near-IR light can be applied for stimulation of MSCs metabolism and proliferation in hydrogel-based constructs with thicknesses up to 3 mm.

Highlights

The formation of cell-containing structures is one of the approaches of tissue engineering in creating bioequivalent tissues and organs
Bikmulina et al.: Beyond 2D: effects of photobiomodulation in 3D tissue-like systems act as a base of these structures, for example, decellularized tissues[1,2,3] or hydrogels.[4,5,6]
We used three different hydrogel types varying in fibrinogen concentration and final hydrogel thickness in a well (Table 1)

Summary

Introduction

The formation of cell-containing structures is one of the approaches of tissue engineering in creating bioequivalent tissues and organs. The diffusion of oxygen and nutrients in tissues and tissue-engineering constructs is limited by distances of 100 to 200 μm.[9,10] At larger distances, foci of necrosis often occur, and the density of living cells decreases significantly.[11,12] Vascularization of the grafts after transplantation due to the growth of the recipient’s capillaries is a slow process; graft rejection frequently occurs due to insufficient vascularization and oxygen starvation.[6] the lack of vascularization is one of the most common causes of a rejection of the transplants of pancreatic islets.[13,14,15]

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