Inserting a special character from an alternate font

I am trying to write chemical equations in the program I am tasked with updating. In the past, the student before me switched to a font called Chemistry Sansserif to input an equilibrium symbol before switching back to Helvetica which is what the rest of the GUI uses. I have been unable to replicate what this student did in the past so I am wondering what syntax is required to create a string with text/symbols from mixed fonts.

Thanks in advance for any help.

[Walter Roberson]

What context is this in? There is some amount of font changes that can be done in TeX / LaTex for strings written using text(), but you cannot mix fonts within one uicontrol()