The phrase "act as surrogate" is correct and usable in written English.
It can be used when referring to someone or something that takes the place of another in a specific role or function.
Example: "In the absence of the team leader, I will act as surrogate to ensure the project continues smoothly."
Alternatives: "serve as a substitute" or "function as a proxy".
Surrogate parents for vulnerable children PADEC has appointed 20 volunteers who act as surrogate parents to orphans and vulnerable children.
But Labour criticised the move, saying it would result in doctors and nurses having to act as "surrogate immigration officials".
If there is a common theme between The Sopranos and Springsteen, aside from New Jersey, it is that for Van Zandt both act as surrogate families.
In the French artist's indelible 1960 hybrids of performance and painting, he directed nude women, slathered in blue, to act as surrogate brushes.
Others are more skeptical that the military possesses the finesse, the nuanced understanding of the regional issues, to act as surrogate diplomats.
In the middle are the two circular touch pads, which act as surrogate analogue sticks and do an impressive job of providing more exact controls.
Both groups act as surrogates for al-Qaida.
"We have found lots of women in Bulgaria offered to sell their babies or act as surrogates for cash.
They're tour guides to a foreign realm who act as surrogates for their audiences, but they're also natives of that realm with privileged access to its inner sanctums.
We outline recent evidence describing their use on immunohistochemical panels which may act as surrogates for gene expression profiling when subtyping breast cancers.
In addition, mobile-based analytics can also act as surrogates for official statistics (e.g., on public health and food security) when not available or when more real-time information is needed.
