Weighted samples in Tensorflow for convolutional neural networks
Same as in case of the weighted classes, you have to account on sample weights in your loss function.

If you use Tensorflow in combination with Keras, you can simply use the sample_weight argument of the model.fit function.

As an alternative, you can implement your own loss function. However, 
depending on your setup/framework it can get tricky to determine sample indices from inside the loss function.