H₂O₂ and Phosphorylated Peptide Dual-Responsive Nanochannel Device

Abstract

Oxidation and protein phosphorylation are critical mechanisms involved in regulating various cellular activities. Increasing research has suggested that oxidative stress could affect the activities of specific kinases or phosphatases, leading to alterations in the phosphorylation status of certain proteins. Ultimately, these alterations can affect cellular signaling pathways and gene expression patterns. However, the relationship between oxidation and protein phosphorylation remains complex and not yet fully understood. Therefore, the development of effective sensors capable of detecting both oxidation and protein phosphorylation simultaneously presents an ongoing challenge. To address this need, we introduce a proof-of-concept nanochannel device that is dual-responsive to both H2O2 and phosphorylated peptide (PP). Specifically, we design a peptide GGGCEG­(GPGGA)4CEGRRRR, which contains an H2O2-sensitive unit CEG, an elastic peptide fragment (GPGGA)4, and a phosphorylation site recognition fragment RRRR. When the peptides are immobilized on the inner walls of conical nanochannels in a polyethylene terephthalate membrane, this peptide-modified nanochannel device exhibits a sensitive response to both H2O2 and PPs. The peptide chains undergo a random coil-to-α-helix transition in response to H2O2, which leads to a close-to-open transition of the nanochannel, accompanied with a remarkable increase in the transmembrane ionic current. In contrast, binding of the peptides with PPs shields the positive charge of the RRRR fragments, causing a decrease of the transmembrane ionic current. These unique features enable the sensitive detection of reactive oxygen species released by 3T3-L1 cells stimulated by platelet-derived growth factor (PDGF) as well as PDGF-induced change in the PP level. Real-time kinase activity monitoring further confirms the device’s potential utility for kinase inhibitor screening.

DNA–Peptide Interaction-Modulated Charge Reversal in Biomimetic Nanochannels for Simple and Efficient Detection of Histone Deacetylases

“…In recent years, researchers have developed biomimetic nanochannel systems capable of converting biochemical reactions into ion signals, offering versatile applications in bioengineering and biosensing. − Notably, a recent development involves the utilization of peptides to modulate the properties of nanochannels for enhanced biosensing capabilities. − For instance, Li et al introduced the charged peptide assembly into a nanoconfined space for the modulation of ion current rectification (ICR) . This is because peptides can be composed of naturally charged amino acids, allowing them to regulate the ICR, ,, which is a distinctive feature of biological ion channels. , ICR is evident in asymmetric current–voltage ( I–V ) curves, where the absolute current values under two opposing voltages differ, indicating a preferred direction of ion flow. , ICR reversal results in more substantial changes in both the I–V curves and the corresponding ICR ratios, enabling a more comprehensive analysis of biochemical information and thereby providing a powerful tool for biosensing.…”