Liquid-to-gel transition for visual and tactile detection of biological analytes

Abstract

So far all visual instrument-free methods are based on the color change. However, colorimetric assays cannot be used by blind or color blind people. Here we introduce a liquid-to-gel transition as a general output platform. The signal output (a piece of gel) can be unambiguously distinguished from liquid both visually and by touch. The approach promises to contribute to the development of accessible environment for visually impaired persons.

Towards sustainable diagnostics: replacing unstable H2O2 by photoactive TiO2 in testing systems for visible and tangible diagnostics for use by blind people

“…The buffer contained acetylacetone, H 2 O 2 , 40% acrylamide/bisacrylamide, hemin and a split deoxyribozyme sensor with peroxidase-like activity (PxR). 2 In the presence of the specic analyte sequence (A1 in this study), the sensor hybridized with the analyte and formed PxR, which bound hemin and decomposed H 2 O 2 to ROS. The latter oxidized acetylacetone to the acetylacetone radical, which initiated the polymerization of acrylamide, resulting in liquid-to-gel conversion.…”

“…Recently, we described an alternative output signal that cannot only be detected by sight, but also by touch and applied it in the detection of adenosine triphosphate (ATP) and deoxyribonucleic acid (DNA). 2 The method is based on the analyte-dependent radical polymerization of acrylamide into polyacrylamide in the presence of hydrogen peroxide (H 2 O 2 ). H 2 O 2 serves as a source of radicals.…”

Recent Advances in Polymer Additive Engineering for Diagnostic and Therapeutic Hydrogels

“…Based on these characteristics, researchers have been exploiting new hydrogel-based smart sensors. DNA hydrogels are categorized into either pure DNA hydrogels formed purely by nucleic acid backbone [ 12 , 33 , 34 , 35 ] or hybrid hydrogels [ 27 , 36 , 37 , 38 , 39 , 40 ] composed of both nucleic acid chains and other gel-forming polymers.…”

DNA hydrogel-empowered biosensing

“…PxD1 and PxD2) that upon binding to ATP formed a full G-quadruplex. By adding the hemin cofactor, H 2 O 2 catalyzed the oxidation of acetylacetone to acetylacetone-radical that initiated the polymerization of acrylamide into polyacrylamide accompanied a sol-to-gel transition [37].…”