[Analysis of properties of collagen membranes before and after crosslinked].
OBJECTIVE
To compare the properties of collagen membranes before and after crosslinked and to establish the foundation of application of collagen membranes.


METHODS
Fresh bovine tendons were separated and collagen was extracted by washing, smashing and acetic acid dissolving. The collagen protein was determined by ultraviolet spectrophotometer and its characteristics were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), wavelength scanning and amino acids detecting. Collagen membranes were produced by lyophilization. And then the biocharacteristics of the membranes before and after glutaraldehyde crosslinked were compared. BMSCs separated from volunteer's bone marrow were seeded on collagen membranes before and after crosslinked by 2 x 10(3) in 100 microL medium, seven days after culture, the absorption spectrum of BMSCs was examined, and BMSCs were observed by scanning electron microscope (SEM).


RESULTS
The contents of collagen protein were 2 mg/mL. The maximum absorption wave length appeared at about 230 nm. SDS-PAGE suggested that molecular weight of main bands was more than 66.2 x 10(3), the same as collagen marker from calf skin. There were 21.47% glycine, 12.04% praline and 10.18% hydroxyproline. No tryptophan was found. Before crosslinked, collagen membranes were in shape of white sponges and with big holes and the range of pH value was from 4.5 to 5.0. SEM showed reticular conformation and pore structure of collagen membranes, but the bore diameter was bigger. Their water-absorbing capacity was 61 times as much as their weight. The mechanical strength was 210 g/cm3. The dissolution time of collagenase was 90 minutes. After crossl inked, collagen membranes became thin, colorless, semi-transparent and compact with better tenacity. Under SEM, compact collagen fiber appeared reticular. There was lower water-absorbing capacity and pH value ranged from 6.5 to 7.0. The mechanical strength was 3,400 g/cm3 and the dissolution time of collagenase became longer. BMSCs could grow better either on before-crosslinked collagen membranes or on after-crosslinked ones.


CONCLUSIONS
As biomaterial scaffolds, after crosslinked collagen membranes were better than before-crosslinked ones.
Chen
Lin
L
Institute of Transfusion Medicine, Academy of Military Medical Sciences, Beijing, 100850, P.R. China.
Lv
Yang
Y
Guan
Lidong
L
Wang
Yunfang
Y
He
Lijuan
L
Li
Yanhua
Y
Bai
Cixian
C
Liu
Daqing
D
Pei
Xuetao
X
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001854:Bone Marrow Cells / Q000166:cytology; D002417:Cattle; D049109:Cell Proliferation; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D017364:Collagenases / Q000378:metabolism; D003432:Cross-Linking Reagents; D004548:Elasticity; D005976:Glutaral / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D013234:Stem Cells / Q000166:cytology; D013718:Tensile Strength; D054457:Tissue Scaffolds; D014332:Tropocollagen / Q000737:chemistry / Q000302:isolation & purification
D000596:Amino Acids; D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D008567:Membranes, Artificial; D014332:Tropocollagen; D003094:Collagen; D017364:Collagenases; D005976:Glutaral