Plasma-Treated Microplates with Enhanced Protein Recoveries and Minimized Extractables

Abstract

SiO2 Medical Products, Inc. (SiO) has developed a proprietary technology that greatly enhances protein recoveries and reduces extractables from commercial microplates used for bioanalytical assays and storage of biologics. SiO technology is based on plasma treatment that chemically modifies the surface of polypropylene with predominantly hydrogen-bond-acceptor uncharged polar groups. The resultant surface resists nonspecific protein adsorption over a wide range of protein concentrations, thereby eliminating the need to passivate (and hence potentially contaminate) the microplates with blocking proteins. High shelf-life stability and cleanliness of the plasma-treated microplates have been demonstrated using five different proteins for two common microplate formats. The protein recovery performance of plasma-treated microplates is found to be higher compared with commercial low-protein-binding microplates.

Characterization of Extractable Species from Polypropylene Microplates

“…Low-protein-binding microplates supplied by SIO, hereinafter referred to as SIO microplates, were molded from polypropylene and plasma treated with a proprietary process to minimize protein binding. 9 Commercial microplates with and without low-protein-binding characteristics were purchased from various commercial sources, including: (1) Porvair Sciences 96-well, 0.5 mL plates (cat. no.…”

“…The SIO plasma-treated and Eppendorf LoBind plates exhibit lower protein binding than standard polypropylene plates. 9 The Porvair Sciences, Greiner, and Nunc microplates have protein-binding character typical of polypropylene. 9 The commercial microplates underwent no additional treatment or coating.…”

“…Higher recoveries were reported for five model proteins in 1.5 nM solutions and 72 h incubation on SIO plasma-treated microplates as compared to a commercial low-protein-bind microplate on the market today. 9 Furthermore, gas chromatography-mass spectroscopy (GC/MS) and liquid chromatography-mass spectroscopy (LC/MS) analysis was conducted after 72 h extraction with acetonitrile and after 72 h extraction with isopropanol, respectively. The total ion chromatograms indicated that the plasma treatment introduced no new extractables and that the chromatograms of SIO microplate extracts were identical to the isopropanol blank.…”

“…The current extractable study expands on the scope of the prior study 9 by including four more commercial microplates and applying more sensitive LC and GC methods with mass spectral detection. This study used a 24 h extraction with isopropanol, followed by injection of a 1 µL aliquot into GC/MS and LC/MS analytical instruments for extractable compound detection.…”

Evaluation of Crystal Zenith Microtiter Plates for High-Throughput Formulation Screening

“…While the use of commercially available microtiter plates composed of polystyrene, polypropylene, and other plastics is attractive for cost and availability reasons, they have the drawbacks of potential material loss due to the protein nonspecifically adsorbing to the surface, the risk of leachables and extractables from the plastic, and potential for aggregation from surface adsorption-desorption. [11][12][13][14][15][16] Glass inserts that are in a 96-well plate format can be a way around plastic-protein interaction and have been previously studied but have the drawback of high cost. 7 A new type of 96-well, microtiter plates that has not been previously studied for biotherapeutic formulation stability studies are plates composed of Crystal Zenith® (CZ).…”