Recently, falsified images have been found in papers involved in research misconducts. However, none of existing image  forgery  detection  methods was designed for molecular-biological experiment images.  We developed a fast blind inquiry method, named FBI-GEL, for  integrity  of  images  obtained  from  two  common  sorts  of molecular  experiments,  i.e.,  western  blot  (WB)  and  polymerase chain reaction (PCR). Based on an optimized pseudo-background capable of highlighting local residues, FBI-GEL can reveal vestiges suggesting inappropriate local modifications on WB/PCR images.  Additionally,  because  the  optimized  pseudo-background is derived according to a closed-form solution, FBI-GEL is computationally efficient and thus suitable for large scale inquiry tasks for WB/PCR  image  integrity.  We  applied  FBI-GEL on  several  papers questioned  by  the  public (PUBPEER),  and  our  results  show that  figures  of  those  papers  indeed  contain  doubtful  unnatural patterns.

FBI-Gel performs blind detection by making invisible unnatural patterns just noticeable. Therefore, the contributions of FBI-Gel are threefold.
(1) Extending background analysis to a new realm, FBI-Gel is the first blind inquiry method for  integrity of gel electrophoresis images. 
(2) FBI-Gel is nearly parameter free, and all its inspection results are derived on the same basis. Therefore, FBI-Gel can avoid false-alarms effectively. 
(3) FBI-Gel operates based on the closed-form solution. It is thus computationally fast and suitable for large-scale inquiry tasks.

We developed a fast blind inquiry method, named FBI-Gel, for integrity of images obtained from western blot (WB) and polymerase chain reaction (PCR) results. 
We have to emphasize two points. First, FBI-Gel was not designed for accusing anyone; instead, FBI-Gel was developed for helping academic community identify problematic figures and irreproducible experiments. Second, whether an image with unnatural pattern invalidates its significance in that very field is beyond the scope of this method. 
We hope the proposed FBI-Gel can help research community and editorial offices of journals not be deceived by forging experimental images of molecular biology.