diff --git a/eBlocks_design.py b/eBlocks_design.py
index 0f717b1678e7f94680962bc3584aa1cf38426ea7..321428363ed034faa31e43d91876a5498cccbe18 100755
--- a/eBlocks_design.py
+++ b/eBlocks_design.py
@@ -170,7 +170,7 @@ def add_bsaI(block_dict: dict, output_path: str = None) -> dict:
 def add_buffer(block_dict: str, output_path: str = None) -> dict:
     """
     add a buffering zone around each block
-    just pick some payload of an other block, the buffer will be removed in biology
+    just pick some payload of another block, the buffer will be removed in biology
     buff1  + B1  + buff2
     ...
     buff19 + B10 + buff20
@@ -187,8 +187,8 @@ def add_buffer(block_dict: str, output_path: str = None) -> dict:
     for i, frag_name in enumerate(list(block_dict.keys())):
         mid_block_index = len(block_list[i+1])//2
         
-        start_buffer = block_list[i+1][mid_block_index-buffer_size:mid_block_index-1]
-        stop_buffer = block_list[i+1][mid_block_index:mid_block_index+buffer_size-1]
+        start_buffer = dfr.reverse_complement(block_list[i+1][mid_block_index-buffer_size:mid_block_index-1])
+        stop_buffer = dfr.reverse_complement(block_list[i+1][mid_block_index:mid_block_index+buffer_size-1])
         
         #the addition of the buffer can create homopolymere
         #set a base different from extremity and start of buffer in between