Thermoresponsive Poly(2-propyl-2-oxazoline) Surfaces of Glass for Nonenzymatic Cell Harvesting

Abstract

As one of the nonenzymatic cell-harvesting technologies, a thermal-responsive surface based on poly­(2-oxazoline)­s has achieved initial success in supporting the adhesion and thermal-induced detachment of animal cells. However, because of the laborious preparation procedure, this technique was only limited to research purposes. In this work, through using poly­(glycidyl methacrylate) (PGMA) as the anchor layer, poly­(2-propyl-2-oxazoline)­s (PPOx) were grafted onto glass wafers through a facile two-step coating and annealing procedure for nonenzymatic cell harvesting. In the first step, the piranha solution-activated glass wafers were immersed into the chloroform solution of PGMA and then annealed for a given period of time to immobilize PGMA onto the glass wafers through the bonding between epoxy groups and hydroxyl groups. In the second step, the PGMA-coated glass wafers were further immersed into the chloroform solution of carboxyl-functionalized PPOx. After annealing, PPOx were immobilized onto the PGMA layer through the bonding between carboxyl groups and the residual epoxy groups. Atomic force microscopy, X-ray photoelectron spectroscopy, and ellipsometry were used to characterize the modified glass wafers. The results of cytocompatibility evaluation showed that the PPOx-coated glass wafers were almost nontoxic and were able to support the adhesion and proliferation of L929 cells well. By lowering the temperature to 8 °C, L929 and Vero cells were successfully detached from the PPOx-coated glass wafers without any enzymatic treatment. Further cultivation has demonstrated that the cooling procedure had little effect on cell viability, and the cells still retained good viability after harvesting.

Temperature-Controlled Screening of Catechol Groups in Poly(N-Isopropylacrylamide-co-Dopamine Methacrylamide) for Cell Detachment

“…Cell viability was analyzed using the CCK-8 assay as previously described . The L929 cells or rBMSCs (40,000 cells/mL) were seeded onto the thermally responsive surface for 200 μL per well.…”

“…Cell viability was analyzed using the CCK-8 assay as previously described. 30 The L929 cells or rBMSCs (40,000 cells/mL) were seeded onto the thermally responsive surface for 200 μL per well. After incubation (24,48, and 72 h), 20 μL of CCK-8 was placed in each well and incubated at 37 °C for 2 h. Finally, 100 μL of supernatant was then added to a new 96-well plate, and the absorbance of each well was measured at 450 nm.…”

“…Scanning electron microscopy (Ultra Plus, Zeiss, Germany) was used to examine the morphology of the cells in the adhered and detached states. After incubation for 24 h, the L929 cells were fixed in paraformaldehyde and dehydrated in an ethanol gradient (30,70,80,90,95, and 100% for 10 min each). Afterward, the dehydrated cells were dried at ambient temperature and then observed by using SEM.…”

A journey towards responsive and circular polymer brushes : design and applications

“…This contrasts with the research on switchable adhesives in non-biological media, detailed in The evaluation of bioadhesive performance typically involves bringing biomaterials into contact with synthetically modified surfaces. These biomaterials may be directly attached to counter-surfaces [252][253][254][255][269][270][271][272][274][275][276]278,279 or used in the form of solvents containing proteins or bacteria. 252,275,277,280,284 In the context of cell harvesting and release, bioadhesive coatings undergo reversible exposure to specific stimuli, with their effectiveness assessed through live/dead tests or cell counts using fluorescence microscopy and other non-invasive techniques.…”

“…These biomaterials may be directly attached to counter-surfaces [252][253][254][255][269][270][271][272][274][275][276]278,279 or used in the form of solvents containing proteins or bacteria. 252,275,277,280,284 In the context of cell harvesting and release, bioadhesive coatings undergo reversible exposure to specific stimuli, with their effectiveness assessed through live/dead tests or cell counts using fluorescence microscopy and other non-invasive techniques. 252,253,279,282 Within this field, PNIPAM-based interfaces are commonly used.…”