In-Silico Prediction on the MSAMS-Assisted Immobilization of Bovine Serum Albumin on 10 MHz Piezoelectric Immunosensors

The biological sensing interface on the active area of a piezo transducer is responsible for the sensitivity, specificity, reusability, and reproducibility of these devices. Among the approaches used to functionalize piezo transducers, mixed self-assembled monolayers (MSAMs) are one of the most successful, given that they allow the obtaining of semi-crystalline molecular arrays and the arrangement of a bioreceptor on the surface. But, to deploy MSAMs on a substrate effectively, one must optimize and characterize the structural ratio between them and the bioreceptor. In this paper, we developed a molecular model of the interaction between Bovine Serum Albumin (BSA) and MSAMs-functionalized gold substrates. First, we evaluated the conditions for the functionalization of the substrates and found that a 50:1 16-mercaptohexadecaonic acid (MHDA) to 11 mercapto-1-undecanol (MUA) ratio produced the best features on the surface. We also evaluated the specific conditions to immobilize BSA on MSAMs (using the afore-established ratio) via Atomic Force Microscopy (AFM), and then on a 10 MHz quartz crystal microbalance (QCM), and with the data obtained we concluded that a structural ratio of 0.005 (MSAM/BSA) is obtained when 1 mu M MHDA and 200 mu g/mL BSA were used, provided the most suitable conditions for the functionalization of a piezo transducer.