Patent ID: 8007991

Claim:
A three dimensional physiological gel matrix suitable for incubating at least one tissue sample from an animal, said tissue sample comprising cells, wherein said cells or said tissue are suspected of being abnormal, cancerous, or pre-cancerous, wherein said physiological matrix comprises: (A) wherein the physiological matrix comprises collagen fibers adapted and arranged such that the cells, if abnormal, cancerous or pre-cancerous, are enabled to grow away from the sample portion into the matrix, and wherein said collagen fiber is present in a density of from 1.3 mg/ml to 3.3 mg/ml, (B) a sufficient amount of at least one additive providing hydroxyl anions or protons to adjust the pH of the matrix into a range suitable for a particular tissue, cell or tumor, and C) nutrition sufficient to sustain said cells and said tissue in the matrix wherein said physiological matrix is formed from components which are essentially free of bicarbonate during the process of forming a gel.