Finding a highest megapixel camera for PC
Your best bet is a DSLR with a lens mount for the microscope.  It goes in places of the eyepiece and generally does not have the diopter from an eyepiece (so magnification is a bit lower, but you can also zoom in).  Among standard size DSLRs, the highest megapixel one I'm aware of at this time is the Nikon D800 at 35 megapixels, but there may be bigger out there now.