Tackling paper mills requires us to prevent future contamination and clean up the past - the case of the journal Bioengineered.

Taylor & Francis journal Bioengineered has been targeted by paper mills. Our goal is to identify problematic articles published in Bioengineered during the period 2010 to 2024. Dimensions was used to search for articles that contained the terms 'mouse' OR 'mice' OR 'rat' OR 'rats' in title or abstract, published in Bioengineered between January 1st 2010 to December 31st 2024. All articles were assessed by eye and by using software to detect inappropriate image duplication and manipulation. An article was classified as problematic if it contained inappropriate image duplication or manipulation or had been previously retracted. Problematic articles were reported on PubPeer by the authors if they had not been reported previously. All included articles were assessed for post-publication editorial decisions. We have excluded all articles published in 2024 from further analysis, as these were all retraction notices. We assessed the remaining 878 articles, of which 226 (25.7%) were identified as problematic, of which 35 had been previously retracted. One retracted article was later de-retracted. One article received a correction. None of the included articles received an expression of concern or the Taylor & Francis 'under investigation' pop-up. Taylor & Francis' lack of visible editorial action has left the scientific community vulnerable to reading and citing hundreds of problematic articles published in Bioengineered. To uphold scientific integrity, Taylor & Francis should use the findings of this study as a starting point to systematically identify all compromised articles in Bioengineered and take appropriate editorial action.