Set the ion-radio as required

Question

I am mounting a dynamic form using ionic2, but multiple choice components do not accept the property required how would I do that on Ionic? The component I’m trying to put property required is the ion-radio I have tried with the ion-checkbox.

Example of the code used.

<ion-list radio-group>
<ion-item *ngFor="‪#‎option‬ of pergunta.lista">
<ion-label>{{option.label}}</ion-label>
<ion-radio value="{{option.label}}" required></ion-radio>
</ion-item>
</ion-template>
</ion-list>

What might be going on?