Discussion

Molecularly imprinted polymers (MIPs), often called plastic antibodies or synthetic receptors, are synthetic alternatives to antibodies in diagnostics, sensors and separations. MIPs offer significant advantages in terms of cost, stability and lead time. Moreover, due to their synthetic nature, they do not require any cold chain storage and can be easily integrated with detection functionalities (e.g. coloured, electro-active, fluorescent, etc.) during synthesis, without affecting their recognition capabilities. MIP nanoparticles (nanoMIPs) are considered to be a robust alternative to antibodies. Whilst antibodies often exhibit batch-to-batch variability, poor performance in non-physiological conditions and, in some cases, short shelf-life, the synthesis of nanoMIPs can be tightly quality controlled. Despite the advantages of nanoMIPs, their production is often time-consuming and laborious. To solve this issue, we developed an automated reactor for a reproducible, controlled and scalable production of nanoMIPs. It relies on the immobilisation of the template molecules onto a solid support which is placed inside the reactor. Process parameters are under computer control, thus requiring minimal manual intervention. NanoMIPs with narrow size distribution and nanomolar Kd are obtained in a matter of hours. Thanks to their excellent affinity and specificity for the target molecule, nanoMIPs can be applied in different fields, ranging from sensors and assays to imaging application. Herein we show that nanoMIPs can be used as synthetic antibodies in competitive ELISA-like assays and can be easily integrated within sensors for quantification of a wide range of molecules. Moreover, fluorescent nanoMIPs targeted towards two different overexpressed proteins present on the cell membrane of senescent and cancer cells were able to selectively bind their target proteins. Currently, such imprinted NPs are being tested as potential drug delivery systems, in order for the drug molecule to be specifically received by the target cell population.