Is there a way to get an Action taking in any Type as only parameter from a Delegate?

I create a Delegate from an method I know only takes one parameter and later call it using a DynamicInvoke, but I was wondering if it was possible to get an Action to invoke directly.

Here is what I have currently:

private Delegate CreateDelegate(MethodInfo method) {
    Type requestType = method.GetParameters()[0].ParameterType,
         actionType = typeof(Action<>).MakeGenericType(requestType);

    return Delegate.CreateDelegate(actionType, this, method);
}

public void Invoke(string json) {
    var requestType = MyDelegate.Method.GetParameters()[0].ParameterType;
    var o = Deserialize(json, requestType);

    MyDelegate.DynamicInvoke(o);
}

Using an Action, not only would it be faster but it would look much neater. The following code doesn't work but there must be a way to get something similar:

private Action CreateAction(MethodInfo method) {
    Type requestType = method.GetParameters()[0].ParameterType,
         actionType = typeof(Action<>).MakeGenericType(requestType);

    return (Action) Delegate.CreateDelegate(actionType, this, method);
}

public void Invoke(string json) {
    Type requestType = MyAction.GetParameters()[0].ParameterType;
    var o = Deserialize(json, requestType);

    MyAction(o);
}