Hundreds of patient samples are tested every day in large hospitals. This is frequently done using fully automatic laboratory systems capable of measuring up to 150 parameters of a single blood sample. However, immunosuppressants such as Tacrolimus and Sirolimus have so far not been among these measured values, as they first had to be extracted from a blood sample before it was possible to reliably determine their concentration – a time-consuming process. Wei, a biochemist, therefore developed a series of processes that enable the concentration of these medications to be determined directly in a Siemens laboratory system, without the need for time-consuming extraction steps.

The immunosuppressive medications bind to proteins in the blood. As a result, it was previously impossible to determine their dose in a blood sample using a fully automatic process, as the laboratory system’s spectrometer no longer recognized them. Wei therefore developed an analog of the medication – an ingredient with a structure similar to that of the medication itself, but with different chemical and biological properties. This analog also binds to proteins, but not to the antibodies that determine the blood level of the medication. Therefore, it can free up the medication from proteins by displacement. The freed medication then becomes measurable by the antibodies. The assay developed by Wei contains magnetic particles that are coated with molecules of the medication. A portion of the antibodies binds to the medication from the patient’s blood sample, and the remaining portion binds to the magnetic particles, and can thus be removed using a magnet. The amount of medication bound to antibodies is directly proportional to that of the medication. The antibodies are chemically linked to a marker molecule that is recognized by the spectrometer of the Dimension® laboratory system developed by Siemens. This is the first fully automatic measurement process for determining these medications.

In order to be able to accurately determine the level of the medication, however, Wei had to solve a further problem. During analysis of a blood sample, the molecules of the medications were absorbed especially well by molecular complexes of so-called lipoproteins – the blood fats. The higher the patient’s cholesterol level, the more difficult it is to obtain an accurate measurement of the medications. Wei therefore went looking for a way to prevent the molecules of the medication from being absorbed by lipoprotein compounds. He found the answer in a detergent that changes the surface tension of the molecules. This detergent prevents lipoproteins from attracting the molecules of the medication, so that the medication is no longer absorbed into the lipoproteins, but remains free and available for measurement.

Wei also made a third invention, in the form of an organic compound that enables the laboratory system to more effectively distinguish original molecules of the medication from those that have already been metabolically changed.  In the measurement of the medication, co-measurement of its metabolic products is generally undesirable. This organic compound increases the solubility of the medication in water, but not so much the solubility of the metabolic products of the medication. Therefore, the medication was made more accessible to the antibodies in the measurement system. As a result, the signal is primarily from the molecules of the medication rather than their metabolic products.

“Life is a fascinating phenomenon for me,” says Wei, “and I personally regard the sciences that concern themselves with human existence as the most important ones.” In order to study the mechanisms of human life, Wei chose biochemistry as his subject of study in his Chinese homeland. He studied for his bachelor’s degree at Nankai University in Tianjin and followed it up with his master’s at the Chinese Academy of Science in Beijing. Wei then worked at the Clinical Research Institute at the Sino-Japan Friendship Hospital in Beijing from 1986 to 1988. He traveled to the Medical Center of the University of Illinois in Chicago for his doctoral work. In 1995, Wei started work as a biochemist for Siemens in Newark, in the US state of Delaware. From the beginning of his work there, his research focused on the fully automatic Dimension® laboratory system. Since 2008 he has been the research director responsible for new developments for fully automatic laboratory analyses. He has 16 inventions and seven granted individual patents issued in 14 IPR families to his name.

Wei lives with his wife, who is also a scientist at Siemens, and their two children in Wilmington, Delaware.