Contract drug manufacturer Thermo Fisher Scientific said on Tuesday it will buy Solventum's purification and filtration business for about $4.1 billion, sending the latter's shares up around 9%. The deal should allow Thermo to enter the filtration category in bioprocessing,

Waltham-based Thermo is buying the business from Solventum, a Minnesota-based company that spun off from manufacturing conglomerate 3M roughly one year ago.