title: Influence of Cross-Linker Concentration on the Functionality of Carbodiimide Cross-Linked Gelatin Membranes for Retinal Sheet Carriers.
abstract: Carbodiimide cross-linking can easily regulate the functionality of gelatin carriers used for retinal sheet delivery. This paper investigates the effect of cross-linker concentrations (0-0.4 mmol EDC/mg gelatin membrane (GM)) on the properties of the chemically-modified GMs. ATR-FT-IR and ninhydrin analyses results consistently indicated that the EDC cross-linking reaction approaches saturation at concentrations around 0.02 mmol EDC/mg GM. The thermal stability and resistance to water dissolution and collagenase digestion were significantly enhanced with increasing cross-linker concentration from 0.001 to 0.02 mmol EDC/mg GM. In addition, the chemical cross-linking did not affect the ability to form a tissue-encapsulating structure at 37°C. Irrespective of their cross-linking degree, the GMs had an appropriate degradation rate sufficient to allow tissue integration. It was noted that, although high cross-linker concentrations can be used to improve the delivery efficiency of gelatin samples, the treatment with 0.1-0.4 mmol EDC/mg GM may lead to poor biocompatibility. Results of Live/Dead and pro-inflammatory cytokine expression analyses showed that the exposure of ARPE-19 cultures to the test materials cross-linked with a concentration ≥0.1 mmol EDC/mg GM induces significant cytotoxicity and high levels of interleukin-1β and interleukin-6. However, the presence of EDC cross-linked gelatin membranes in the culture medium had no effect on the glutamate uptake capacity. It is concluded that among the cross-linked gelatin samples studied, 0.02 mmol EDC/mg GM is the best cross-linker concentration for preparation of retinal sheet delivery carriers.
authors.affiliation: a Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China; Biomedical Engineering Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China; Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China.
authors.forename: Jui-Yang
authors.initials: JY
authors.lastname: Lai
authors.forename: Ya-Ting
authors.initials: YT
authors.lastname: Li
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002234:Carbodiimides / Q000737:chemistry; D016923:Cell Death / Q000502:physiology; D002460:Cell Line; D017364:Collagenases / Q000737:chemistry; D016207:Cytokines / Q000378:metabolism; D005780:Gelatin / Q000737:chemistry; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D007910:Lenses, Intraocular; D008422:Materials Testing; D023421:Models, Animal; D011817:Rabbits; D012160:Retina / Q000502:physiology / Q000601:surgery / Q000637:transplantation; D017550:Spectroscopy, Fourier Transform Infrared; D046509:Tissue Culture Techniques; D054457:Tissue Scaffolds / Q000737:chemistry; D044366:Transition Temperature; D014867:Water / Q000737:chemistry
chemical_list: D002234:Carbodiimides; D016207:Cytokines; D014867:Water; D018698:Glutamic Acid; D005780:Gelatin; D017364:Collagenases