C# Excel Replace text in a range
 

Hi all! I am using C# to access Excel. I have the following situation.

I have a cell with the following text: "Some text {a} and another text
{b}"
I want to replace {a} and {b} with a specific string and this string
to be with a specific Font. I am using get_characters to change the
font only for these characters. But when I replace {b} and change the
font of its replacement, the other text font in the cell is set to
default (including the replacement of {a}). My question is how can I
workaround this problem? How can I replace {a} and {b} and change the
font of their replacement?