S9.6 Antibody-Mediated Wireless Portable Biosensor with Multiple Affinity Enhancements for Comprehensive Detection of Nucleic Acid in Serum

Creating biosensors capable of facilely and entirely excluding the influence of interfering biomolecules in complex samples holds profound significance for advancing detection technology and diagnostics. Here, we develop a wireless portable biosensor (WPB) that prevents interference from abundant biomolecules in serum through homogeneous hybridization and S9.6 antibody-mediated multivalent capture. By transferring the hybridization environment from a heterogeneous chip surface to a homogeneous solution, the biosensor maintains consistent hybridization efficiency in serum as in buffer. Additionally, the use of S9.6 antibody-mediated multivalent capture ensures nearly unchanged binding affinity in serum compared to buffer. On the basis of the multiple affinity enhancements, S9.6 antibody-mediated WPB can achieve ultrasensitive detection of nucleic acid in 50% human serum. Specifically, a subtle blocker is designed to eliminate the competitive monovalent S9.6 antibody-heteroduplex binding, ensuring the efficiency of multivalent S9.6 antibody-heteroduplex interactions. The blocker also enables single-step detection. Moreover, the sensing platform utilizes interferents in serum as in situ antifouling biomolecules to prevent nonspecific adsorption. As a result, the proposed WPB achieves a similar limit of detection for nucleic acids in human serum (95 aM) and in buffer (86 aM). This approach inspires a new idea for complex interference elimination and usage and exhibits comprehensive detection performance in complex samples with potential future diagnostic applications.