The nose is comprised of 3 parts, bone, upper lateral cartilages and lower lateral cartilages. Nasal bone and upper lateral cartilages are not movable, but lower lateral cartilages(nasal tip portion) are freely movable.
Aloplastic material such as silicone or gore-tex can be used for dorsal portion(bone and ulcs), but, I think it's not good idea to used aloplastic material for tip surgery. For tip surgery, autologous material such as earlobe cartilage or septal cartilage is the choice.
Personally, as a cosmetic surgeon, I use silicone or gore-tex for dosal potion augmentation, and septal cartilage for tip surgery with endonasal approach (with no columellar cut).