GSH-responsive self-healable conductive hydrogel of highly sensitive strain-pressure sensor for cancer cell detection

Abstract

Herein, a selective strain- and pressure-sensitive hydrogel-based wireless soft-electronic skin sensor with self-healing properties was designed for detection of cancer cells. The polydopamine-loaded glutathione-responsive polymer dot (PDA@PD) selectivity towards CD44 receptor in hydrogel matrix was identified to play vital role in strain-pressure selectivity as well as self-healing behavior in the presence of cancer cells. The hydrogen bonding released PDA from disulfide cross-linked PD affected controllable conductivity of PDA@PD-PAAm hydrogel in different cellular microenvironments. Under applied strain and pressure, this sensor could distinguish electronic signals from cancer cell-treated hydrogels by producing higher electronic signals (ΔR/R0 ≈ 23%) compared to normal cell-treated hydrogel (ΔR/R0 ≈ 15%). Moreover, the presence of cancer cells could be indicated by self-healing phenomenon that did not occur in normal cell-treated hydrogel. This sensor demonstrated excellent selectivity towards various cancer cell types, with distinct strain and pressure responses, even in cancer-normal cell co-culture with various ratios. Additionally, real-time electronic signal from strain-pressure response and self-healing can be monitored easily by using wireless devices and smartphones. Therefore, wireless soft skin sensor has the potential to be used for simple and sensitive cancer detection, such as for circulating tumor cells (CTC) or tumor tissue during surgery, allowing for point-of-care diagnostics.