Which of the following is not included in Route 1 of gas foaming methods?

Route 1 of gas foaming methods typically involves a specific sequence of steps to create porous scaffolds in tissue engineering applications. This process starts with the introduction of a foam-forming agent, such as ammonium bicarbonate, which decomposes during the foaming process to create gas bubbles within the polymer matrix.

In this route, the use of high pressure CO2 is indeed a crucial step, as it facilitates the dissolution of gas within the polymer and prepares the material for subsequent foaming. This is followed by a rapid decrease in pressure to atmospheric levels, which leads to the expansion of the dissolved gas and ultimately the formation of pores in the material. Both high pressure CO2 and the rapid decrease in pressure are integral components of Route 1, emphasizing their importance in achieving the desired structure of the porous scaffold.

Therefore, the inclusion of ammonium bicarbonate as a foam-forming agent is relevant and necessary for this method, while options regarding high pressure CO2 and rapid pressure decrease are fundamental to the process itself. Thus, the correct understanding of the methods shows that none of these components are outside the standard procedure for Route 1, validating the choice that options b and c, which refer to critical steps in the process, are indeed involved.