Optimization of ultraviolet ozone treatment process for improvement of polycaprolactone (PCL) microcarrier performance

Abstract

Growing cells on microcarriers may have overcome the limitation of conventional cell culture system. However, the surface functionality of certain polymeric microcarriers for effective cell attachment and growth remains a challenge. Polycaprolactone (PCL), a biodegradable polymer has received considerable attention due to its good mechanical properties and degradation rate. The drawback is the non-polar hydrocarbon moiety which makes it not readily suitable for cell attachment. This report concerns the modification of PCL microcarrier surface (introduction of functional oxygen groups) using ultraviolet irradiation and ozone (UV/O) system and investigation of the effects of ozone concentration, the amount of PCL and exposure time; where the optimum conditions were found to be at 60,110.52 ppm, 5.5 g PCL and 60 min, respectively. The optimum concentration of carboxyl group (COOH) absorbed on the surface was 1495.92 nmol/g and the amount of gelatin immobilized was 320 ± 0.9 µg/g on UV/O treated microcarriers as compared to the untreated (26.83 ± 3 µg/g) microcarriers. The absorption of functional oxygen groups on the surface and the immobilized gelatin was confirmed with the attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR) and the enhancement of hydrophilicity of the surface was confirmed using water contact angle measurement which decreased (86.93°-49.34°) after UV/O treatment and subsequently after immobilization of gelatin. The attachment and growth kinetics for HaCaT skin keratinocyte cells showed that adhesion occurred much more rapidly for oxidized surfaces and gelatin immobilized surface as compared to untreated PCL.

Enhancing Cell Proliferation and Osteogenic Differentiation of MC3T3-E1 Pre-osteoblasts by BMP-2 Delivery in Graphene Oxide-Incorporated PLGA/HA Biodegradable Microcarriers

“…Bone tissue engineering, which shows great potential in developing bone grafts to induce bone tissue regeneration, has thus attracted considerable attention. Cell microcarriers composed of biodegradable polymers, such as poly (lactide) (PLA), polycaprolactone (PCL) and poly (lactide-co-glycolide) (PLGA), are among the most effective candidates due to their unique properties for bone tissue regeneration 5 – 7 . Furthermore, the main advantage of biodegradable microcarriers is that they provide a large number of cells for the field of cell therapy and can be administered using 10 to 16-gauge needles at the bone defect site 8 , 9 .…”

The Effect of Ozone Treatment on the Physicochemical Properties and Biocompatibility of Electrospun Poly(ε)caprolactone Scaffolds

“…The ATR-FTIR spectra ( Figure 4 a) of untreated and O 3 -treated scaffolds featured typical peaks for PCL: 2943 cm −1 asymmetric CH 2 stretching; 2865 cm −1 symmetric CH 2 stretching; 1721 cm −1 carbonyl (C=O) stretching; 1294 cm −1 C–O and C–C stretching in the crystalline phase; 1159 cm −1 C–O and C–C stretching in the amorphous phase; 1241 cm −1 asymmetric C–O–C stretching; 1185 cm −1 OC–O stretching. Such spectra have been registered in earlier studies [ 42 ]. …”

Light‐Induced Surface Modification of Natural Plant Microparticles: Toward Colloidal Science and Cellular Adhesion Applications

“…Major peaks in untreated (0 min) pollen were assigned from previous FTIR studies on sporopollenin, with peak attributions being hydroxyl (3300 cm −1 ), aliphatic (2925 cm −1 ), carbonyl (1670 cm −1 ) aromatics (1515 cm −1 , 1425 cm −1 ), and COR (1028 cm −1 ) ( Figure a and Figure S7a, Supporting Information) . Subtracting UV–O treated spectra from untreated spectra suggested reductions in absorption for most major peaks of interest, and highlighted a relatively large increase in the shoulder peak at 1718 cm −1 (Figure b), which may be attributed to CO and correlates to the increased R 2 CO binding observed from the XPS analysis.…”

“…However, ultraviolet–ozone (UV–O) treatment is a more easily implementable surface modification process, which also leads to improved surface wetting of polymers, and potential enhancements in polymer/cell adhesion . Studies with polymer microparticles have shown UV–O treatment to easily and successfully modify the chemistry and interfacial properties of polystyrene and polycaprolactone microparticles leading to improved wetting, particle self‐assembly, polymer binding, and particle/cell adhesion …”