Magdy Elnashar, who studied for a PhD at Leeds University, is thought to have links to a flat in Leeds being searched by anti-terrorist officers.
He was detained in a suburb of Cairo following a worldwide search involving the FBI, Interpol and other agencies.
Leeds University said Elnashar came to Leeds to study for a PhD in the school of biochemistry in October 2000.
His subject was "Development of a novel matrix for the immobilisation of enzymes for biotechnology" and he was sponsored by the National Research Centre in Cairo.
He was awarded his PhD on May 6 this year.
"We understand he was seeking a post-doctoral position in the UK, and that his visa was updated by the Home Office early this year. He has not been seen on the campus since the beginning of July," the university said.
He was working on a project backed by a regional development agency Yorkshire Forward which gave him access to £30,000 but that was not taken up.
A man who knew the scientist told the Yorkshire Post: "He was extremely charming and very intelligent, a very typical Egyptian with perfect manners. He was obviously quite a brilliant chemist."
The man said there was "nothing remotely sinister" about his work.
"It's like making margarine. It's straightforward and highly commercial," he told the paper."
* An Islamic bookshop was the latest property in Leeds to be raided by police investigating the London suicide bombs. Officers sealed off the Iqra learning centre in the Beeston area of Leeds at around midday. The building, in Bude Road, is around the corner from the home of Shehzad Tanweer, who killed seven people in the Aldgate blast.
According to signs outside the shop, the centre provides not only Islamic literature but media services, youth activities, orphan sponsorship and seminars and presentations.