1737
The Sierpinski tetrahedron-based antennas were fabricated by two methods , the first involves printing the antenna out of acrylonitrile butadiene styrene ( ABS ) , followed by spin casting a coating of an ABS solution containing graphene flakes produced through electrochemical exfoliation , the second method involves 3D printing the antenna from graphene-impregnated polylactic acid ( PLA ) filament directly without any coating .
 concept or principle: fabricated; material: acrylonitrile butadiene styrene; material: ABS; manufacturing process: casting; application: coating; material: ABS; material: graphene; concept or principle: flakes; concept or principle: electrochemical; manufacturing process: 3D printing; material: polylactic acid; material: PLA; material: filament; application: coating
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: fabricated, acrylonitrile butadiene styrene, ABS, casting, coating, ABS, graphene, flakes, electrochemical, 3D printing, polylactic acid, PLA, filament, coating 
Answer:
 concept or principle: fabricated; material: acrylonitrile butadiene styrene; material: ABS; manufacturing process: casting; application: coating; material: ABS; material: graphene; concept or principle: flakes; concept or principle: electrochemical; manufacturing process: 3D printing; material: polylactic acid; material: PLA; material: filament; application: coating