Brighton failed to sign Tottenham striker Vincent Janssen as the club's deadline day search for a striker proved unsuccessful.
The Seagulls hoped to bring in Janssen, who Spurs bought for £17m last summer, on loan but the 23-year-old Netherlands international turned down the move.
Talks for Deportivo La Coruna forward Florin Andone and Fiorentina striker Khouma Babacar also broke down.
However Newcastle goalkeeper Tim Krul did arrive on a season-long loan.
Krul will be re-united with former Newcastle manager Chris Hughton, who described the 29-year-old Dutchman as "an excellent professional" with "vast experience".
Brighton have also signed former Inter Milan defender Ezequiel Schelotto from Sporting Lisbon for £2.75m.
The Argentina-born right-back, who holds Italian citizenship, has joined the Seagulls on a three-year deal.
Schelotto, 28, played 26 times for Sporting last season, having joined the Portuguese side from Inter in 2015.
"He has played in the Champions League and is the type of experienced player we wanted to add to the squad," Hughton said.
Goalkeeper Krul joined Ajax on loan last season, before switching to fellow Dutch side AZ Alkmaar in January.
He made 16 appearances with Alkmaar and helped them to a sixth-placed finish in the Eredivisie.
Brighton have yet to score in their opening three Premier League games.
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