To get $SLN to Base, you will need to bridge it.

Some options: 
From ETH: Useto bridge $SLN to Base. 
Official $SLN CA on Base: 0xef0b105b4f2ce61d2a7ae62d03b1f4cb6c4fbeec  

To purchase $SLN on Base, you can use: 
Dodoex:Kyber Swap:2/2
#SLN #SLN #SLN #SLN