Organic electrochemical transistors (OECTs) have great potential in the field of portable biosensors due to their low operating voltage, high signal amplification capability, and biocompatibility. However, the dense active layer of traditional OECT severely limits ion permeation and transport efficiency, resulting in insufficient transconductance and sensitivity. Currently, developing portable devices with high sensitivity, selectivity, and the ability to detect trace biomolecules remains a major challenge for early disease warning and precision medicine.

Inspired by the directional ion channel in the human olfactory system, the cooperative team of Professor Huang Jia, Professor Xu Yang and Assistant Professor Zu Guoqing of Tongji University developed the directional nano channel semiconductor aerogel and aerogel based OECT for the first time through the liquid crystal template strategy. The vertical nanochannel structure significantly improves ion transport efficiency, resulting in a transconductance of up to 118.5 mS, which is 4-10 times higher than similar sized OECTs. The detection limits of the microfluidic biosensor system based on this for uric acid (UA), immunoglobulin G (IgG), and DNA are 1 pM, 0.01 fg mL ⁻¹, and 0.1 pM, respectively, which are 1-3 orders of magnitude lower than traditional devices. It can detect trace biomarkers in body fluids such as urine and serum in real time.

Figure 1 shows the bionic design concept: human olfactory neurons achieve efficient transmembrane transmission through vertically arranged ion channels, and the team designed the vertical nano channel aerogel active layer (Figure 1B) to optimize the ion diffusion path. The preparation and structure of the material were revealed: the liquid crystal monomer RM257 formed horizontal or vertical templates under the guidance of the orientation layer (polyimide or DMOAP). After UV photopolymerization and freeze drying, nanochannel aerogels were obtained. The semiconductor polymer is deposited in the template to form an aerogel film. Its vertical channels (pore size 20 – 200 nm) are anisotropic under the polarizing microscope. The scanning electron microscope clearly shows that the channels are perpendicular to the film surface. The nitrogen adsorption test confirmed its high specific surface area (163.8 m ² g ⁻¹) and through-hole structure.