Coexistence of multiferroic orders attached increasing attentions on its potential applications in multiple-state memory, switch, and computing, but it is still challenging to design the single-phase crystalline materials hosting multiferroic...

Proteins, due to their binding selectivity, are promising candidates for fabricating nanoscale bio-sensors. However, the influence of structural change on protein conductance caused by specific protein-ligand interactions and disease-induced degeneration still remains unknown. Here, we excavated the relationship between circular dichroism (CD) spectroscopy and conductive atomic force microscopy (CAFM) to reveal the effect of the protein secondary structures changes on conductance. The secondary structure of bovine serum albumin (BSA) was altered by the binding of drugs, like amoxicillin (Amox), cephalexin (Cefa), and azithromycin (Azit). The CD spectroscopy shows that the α-helical and β-sheet content of BSA, which varied according to the molar ratio between the drug and BSA, changed by up to 6%. The conductance of BSA monolayers in varying drug concentrations was further characterized via CAFM. We found that BSA conductance has a monotonic relation with α-helical content. Moreover, BSA conductance seems to be in connection with the binding ability of drugs and proteins. This work elucidates that protein conductance variations caused by secondary structure transitions are triggered by drug-binding and indicate that electrical methods are of potential application in protein secondary structure analysis.

Implementing stretchable memory is the key toward an intelligent device possessing wearability and implantability. In this work, we construct a stretchable ferroelectric field effect transistor (Fe-FET) based on buckled poly(vinylidene fluoride-trifluoroethylene)/poly(3-hexyl thiophene) [P(VDF-TrFE)/P3HT] bilayers. The fabrication procedure avoids complicated etching steps and photolithography process, which significantly reduce the need for equipment and prevent harm to the polymers. Multilevel storage capacity and photomodulated resistance are achieved in the stretchable Fe-FET, in which the conductance of the P3HT layer can be continuously adjusted by the polarization of the P(VDF-TrFE) layer. The stored information remains stable under 20% tensile deformation and is retained even after 2000 stretching/releasing cycles. The good mechanical stability and multilevel storage capacity make this stretchable Fe-FET potential for utilization in smart labels, epidermal systems, and even biointegrated artificial synapses.

The high stability to maintain stored information under mechanical deformation is an essential requirement for the practical applications of stretchable electronics. In addition to storage stability, large deformation and easy fabrication are also desirable features for stretchable devices. In this work, we use wavy P(VDF-TrFE) nanoribbons to achieve a mechanical deformation of more than 20%, and the fabricating procedure eliminates the need for complicated etching steps and lithographic masks. The stored information, which is written on the ribbons in the form of ferroelectric domains, is able to remain unchanged after large mechanical deformation. After 10 000 stretching/releasing cycles, the polarization orientation remains the same with very little change of the intensity. These P(VDF-TrFE) nanoribbons with large deformation and high stability demonstrate great potential for the enhanced storage performance of future stretchable electronics.