This would be a very complex undertaking, even without taking into account the institutional context which would necessarily involve intervention in 17 countries. But the ECB has taken a number of measures on this front too. Banks have for some time been able to use credit claims as collateral when obtaining funding from the ECB.
And we should not underestimate the effectiveness of traditional monetary policy when general conditions change. As mentioned, the Governing Council of the ECB cut interest rates to 0.5% at its last meeting, bringing them to a historic low after eight months in which they had been unchanged at 0.75%.