As far as I know there is nothing predefined. But what you can do is, to add a lookahead to the word boundary, to check if it is the start or the end of the word.
\<
would be then \b(?=\w)
. This checks if after the word boundary a word character is following ==> start of the word. See this as example on regexr
\>
would be then \b(?!\w)
. This checks if after the word boundary not a word character is following ==> end of the word