with the group a b and c samples we can analyze the quantity of the cells 4 b galactosidase from the testing of the b galactosidase in the cells cultivated together with the group a b and c samples we can measure the senescence of the cells 5 chromosome aberration a giemsa stain is used to test the chromosome aberration cultivated together with the group a b and c samples we can know about the genetic toxicity of the group a b and c samples to the cells the testing results are listed in the following table wherein the control group in the table is the aforementioned standard collagen solution from the table above we can observe that the group a b and c samples the mitochondrial enzyme activity mtt lactate dehydrogenase ldh total dna content b galactosidase and chromosome aberration are statistically consistent and thus it shows that group a b and c samples do not contain cell poison and cause a change of chromosomes and these samples have a good biocompatibility from the data as shown in the table the main difference between the long lasting collagen of the invention and the conventional collagen resides on that 1 the invention complies with the novelty and improvement requirements of a patent application in the present invention the u03b3 polyglutarmic acid u03b3 pga is added into a collagen and gone through a crosslinking process twice to obtain the long lasting collagen so as to overcome the shortcomings of the conventional collagen having a short storage time and requiring a frequent resupply of collagen by injection 2 the invention complies with the practicability requirement of a patent application in the.