Responsive hydrogel sensor for monitoring antibody production
September 23-26, 2018
Precise control over the biomanufacturing process is crucial for maximizing yield and quality of monoclonal antibodies (mAbs); however, the industry does not have sensors capable of continuously monitoring either mAb yield or quality. Consequently, this production is plagued with poor quality control, reduced productivity, and increased costs. To develop such a sensor, we investigated the use of aptamers selective to human immunoglobulin G (IgG, sub-type of mAbs). First, we investigated the physiochemical properties of six different aptamers that bind to two distinct regions of the protein as well as tested their the binding affinity to human IgG, before and after standard sterilization procedures (autocalve and gamma irradation), using surface plasmon resonance (SPR, Figure 1). Chemical modification procedures were developed for immobilization of the aptamers onto a biotin capture sensor chip for use in SPR. Based on these results, two aptamers were selected which bind to separate regions of IgG, which have optimal physiochemical properties and have strong binding affinity to IgG. Similarly, the aptamers were modified to covalently bond and incorporate into a hydrogel network creating an IgG-sensitive hydrogel. In the presence of IgG in solution, both immobilized aptamers bind to the IgG molecule and form a new crosslink which subsequently causes shrinking (volume reduction) of the hydrogel . This change in volume is monitored using our patent-pending magnetic transduction technique . The degree of hydrogel shrinkage is measured using a magnetometer chip and fixing a permanent magnet to the hydrogel surface. An electronic reader with the magnetometer transduces the hydrogel response into an electrical signal. Response tests using this setup were performed in four different complex environments including industrial cell culture medium. The results show that this IgG-sensitive hydrogel is stable to autoclave and gamma irradition and responds to increasing and decreasing concentrations of IgG in various solutions (Figure 2). The magnitude of hydrogel response is used to correlate the change in IgG concentraion.
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Nicholas Frazier, Seunghei Cho, Yoonsung Goo, Prashant Tathireddy, Rohit Sharma, and Jules J. Magda, "Responsive hydrogel sensor for monitoring antibody production" in "Single-Use Technologies III: Scientific and Technological Advancements", Weibing Ding, Amgen Martina Micheletti, University College London Robert Repetto, Pfizer Eds, ECI Symposium Series, (2018). http://dc.engconfintl.org/sut_iii/51