Both males were picked up by gardai from Ballyfermot and Clondalkin who conducted a number of searches this morning.
Both of them have been detained at Garda stations in west Dublin under the provisions of Section 4 of the Criminal Justice Act 1984.
Alanna and her friend were set upon at the Civic Centre on the Ballyfermot Road at approximately 9.30pm on December 30.
She suffered horrific facial injuries including broken bones in her cheek and eye socket, and broken teeth, but the worst injury was to her right eye which was ruptured in the attack.
Her male friend suffered stab wounds as he tried to fend off the aggressors and help her.
After surgery Alanna was told there was just a 10pc chance she would see with her eye again.
She is now home from hospital but is facing further surgery to her eye, as well as an operation to repair the damage to her cheek bones and eye socket.
Alanna’s mother Jamie revealed how her daughter was feeling nauseous and cannot eat. “I got her jars of baby food today hoping she’ll be able to take that and help get her strength back.
"At least she’s here now and we can all take care of her, and her friends can call. It was difficult when she was in hospital because she was only allowed one visitor.”
A GoFundMe page launched to raise funds for Alanna and her friend has now reached more than €50,000.
“I don’t even know how to express my gratitude to each and every person,” Jamie said. “Not only for the donations – the love and encouragement is just as appreciated.”
Last Thursday, Alanna and a friend were attacked after getting off a bus. The friend was injured while defending her.
It is understood that CCTV from Ballyfermot and the bus network will provide crucial evidence in the investigation.
Gardaí at Ballyfermot are appealing for witness who may not yet have come forward and in particular motorists who may have dash cam footage from Ballyfermot Road between approximately 9.15pm and 10pm on December 30 to contact them at Ballyfermot Garda Station 6667200 or the Garda Confidential line 1800 666 111.