Well-to-well transfer of HaloTag ligand 6-chlorohexan-1-ol and formaldehyde in a multi-well plate.

When volatile organic compounds are handled in multi-well plates, their volatilization is known to affect non-treated wells in the plate. In this paper, we report two cases in which the HaloTag ligand 6-chlorohexan-1-ol and formaldehyde were volatilized and transferred to other wells in a multi-well plate. We found that competition between the HaloTag-targeting PROTAC and 6-chlorohexan-1-ol affected the other wells of the plate. A multifaceted analysis revealed that this phenomenon resulted from well-to-well transfer of 6-chlorohexan-1-ol into untreated wells on the plate. In addition, the formaldehyde used for cell fixation was toxic to cells in the surrounding wells. Therefore, even these reagents, which are widely used in life science research, require careful handling in multi-well plates.