Validation and scalability of homemade polycaprolactone macrobeads grafted with thermo‐responsive poly(N‐isopropylacrylamide) for mesenchymal stem cell expansion and harvesting

Abstract

In this study, polycaprolactone (PCL) macrobeads were prepared by an oil-in-water (o/w) emulsion solvent evaporation method with poly(vinyl alcohol) (PVA) as an emulsifier and conjugated to poly(N-isopropylacrylamide) (PNIPAAm) to be used as cell carriers with noninvasive cell detachment properties (thermo-response).Following previous studies with PCL-PNIPAAm carriers, our objectives were to confirm the successful conjugation on homemade macrobeads and to show the advantages of homemade production over commercial beads to control morphological, biological, and fluidization properties. The effects of PCL concentration on the droplet formation and of flow rate and PVA concentration on the size of the beads were demonstrated. The size of the beads, all spherical, ranged from 0.5 to 3.7 mm with four bead categories based on production parameters. The morphology and size of the beads were observed by scanning electron microscopy to show surface roughness enhancing cell attachment and proliferation compared to commercial beads. The functionalization steps with PNIPAAm were then characterized and confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersion spectroscopy. PNIPAAm-grafted macrobeads allowed mesenchymal stem cells (MSCs) to spread and grow for up to 21 days. By reducing the temperature to 25°C, the MSCs were successfully detached from the PCL-PNIPAAm beads as observed with fluorescence microscopy. Furthermore, we validated the scalability potential of both macrobeads production and conjugation with PCL, to produce easily kilograms of thermo-responsive macrocarriers in a lab environment. This could help moving such approaches towards clinically and industrially relevant processes were cell expansion is needed at very large scale.

Towards Ready-to-Use Iron-Crosslinked Alginate Beads as Mesenchymal Stem Cell Carriers

“…Another advantage is the interconnected macro-porosity of the bead bed when carriers are packed together compared to bulk porous materials hosting closed pores. Moreover, they can be used both as cell carriers in static systems and as fluidized bed in perfused bioreactors to benefit from mechanical signals and automatic nutrients renewal [10][11][12][13]. After cell expansion, cells can either be detached from the bead surface to be injected or used for further tissue-engineering approaches [6], or be implanted with the beads into defects as a hybrid cell/biomaterial composite [14].…”

Preparation of Axially Grafted Temperature-Responsive Chiral Salen MnIII and Application in Asymmetric Epoxidation of Olefins in Water

“…温度响应性高分子聚合物聚 N-异丙基丙烯酰胺 PNIPAAm 具有非常广泛的应用, 可用于生物传感 [1] 、药 物缓释 [2] 、催化载体 [3] 和细胞分离等 [4] . 目前文献已报道 的温度响应性材料中, 聚 N-异丙基丙烯酰胺(PNIP-AAm) 因最低临界温度(32 ℃ ) 接近室温而被广泛应 用 [5][6][7] .…”