Collagen Membranes with Ribonuclease Inhibitors for Long-Term Stability of Electrochemical Aptamer-Based Sensors Employing RNA

Electrochemical aptamer-based (E-AB) sensors offer advantageous analytical detection abilities due to their rapid response time (seconds to minutes), specificity to a target, and selectivity to function in complex media. Ribonucleic acid (RNA) aptamers employed in this class of sensor offer favorable binding characteristics resulting from the ability of RNA to form stable tertiary folds aided by long-range intermolecular interactions. As a result, RNA aptamers can fold into three-dimensional structures more complex than those of their DNA counterparts and consequently exhibit better binding ability to target analytes. Unfortunately, RNA aptamers are susceptible to degradation by nucleases, and for this reason, RNA-based sensors are scarce or require significant sample pretreatment before use in clinically relevant media. Here, we combine the usefulness of a collagen I hydrogel membrane with entrapped ribonuclease inhibitors (RI) to protect small molecule RNA E-AB sensors from endogenous nucleases in complex media. More specifically, the biocompatibility of the naturally polymerized hydrogel with encapsulated RI promotes the protection of an aminoglycoside-binding RNA E-AB sensor up to 6 h, enabling full sensor function in nuclease-rich environments (undiluted serum) without the need for prior sample preparation or oligonucleotide modification. The use of collagen as a biocompatible membrane represents a general approach to compatibly interface E-AB sensors with complex biological samples.