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Another important feature of bone implants is the permeability of the porous metal since the transportation of cells , nutrients and growth factors require the flow of blood through the porous scaffolds .
 engineering feature: feature; application: bone implants; machanical property: permeability; material: porous metal; application: cells; engineering feature: porous scaffolds
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 engineering feature: feature; application: bone implants; machanical property: permeability; material: porous metal; application: cells; engineering feature: porous scaffolds