Development of a portable device for the detection of anti-PEG antibodies in human plasma

The conjugation of biological drugs with polyethylenglycole is widely used to reduce their immunogenicity, thereby enhancing the safety and efficacy of the drugs. For instance, some extended half-life drugs for hemophilia A patients are PEGylated FVIII products. Unfortunately, it was observed that PEG itself, whether derived from PEGylated drugs or present in everyday products (such as cosmetics or medical devices) may induce the production of anti-PEG antibodies, resulting in hypersensitivity reactions and/or loss of efficacy of PEGylated drugs. There is therefore a demand for cost-effective and rapid point-of-care (POC) measurements. To this end, a POC device based on the principle of surface plasmon resonance (SPR) is here presented. The sensor chip is functionalized directly with PEG chains via thiol chemistry and inserted into a holder manufactured in 3D printing technology. The functionalization process has been optimized to recognize anti-PEG antibodies (both IgG and IgM isotypes) and characterized using X-ray Photoelectron Spectroscopy and contact angle measurements. Dose-response curves were obtained using commercially available antibodies, both in buffer solution and in diluted human serum, achieving a limit of detection in the nanomolar range. The reusability of the optical chip was also evaluated and, as proof of concept, plasma from control subjects and hemophilia A patients treated with PEGylated FVIII were measured, comparing the results with standard techniques such as a commercial SPR instrument and an enzyme-linked immunosorbent assay. The results were obtained within 15 min from tenfold diluted human plasma, paving the way for an easy-to-use, small-sized, portable, and low-cost POC device capable of detecting anti-PEG antibodies.