diff --git a/src/resources.py b/src/resources.py
index bf1e137..2ee8ec7 100644
--- a/src/resources.py
+++ b/src/resources.py
@@ -99,7 +99,7 @@ class SampleResource(Resource):
         :return:
         """
         samples = SampleMetadata.query.all()
-        return self.samplemetadataschema.dumps(list(samples)), 200
+        return self.samplemetadataschema.dump(list(samples)), 200
 
 
 class SampleParameterResource(Resource):
@@ -116,4 +116,4 @@ class SampleParameterResource(Resource):
         :return:
         """
         sample = SampleMetadata.query.filter_by(tag=tag).first_or_404()
-        return self.samplemetadataschema.dumps(sample), 200
+        return self.samplemetadataschema.dump(sample), 200