Target-responsive DNA hydrogel for non-enzymatic and visual detection of glucose

Abstract

We have successfully developed a target-responsive aptamer cross-linked hydrogel for the visual detection of glucose, an important biomedical analyte. In this work, the glucose-responsive hydrogel was prepared using the target aptamer and its two short complementary DNA strands grafted onto a linear polyacrylamide chain as cross-linkers. Gold nanoparticles (AuNPs) modified with thiol-PEG were encapsulated in the gel and used as the output signal for visible detection. The complex of glucose and its ligand of boronic acid derivatives (Shinkai's receptor) can bind with the aptamer to disrupt the hydrogel, leading to the release of AuNPs with a distinct red colour in the supernatant. By this method glucose can be detected with the naked eye, and the sensor has a detection limit of 0.44 mM in buffer with the help of UV-Vis spectrophotometry. Furthermore, glucose spiked in 50% urine and 30% serum could also be detected respectively with the naked eye, and glucose was quantitatively detected in 50% urine. The hydrogel system provides a non-enzymatic and visual method for glucose detection, and offers promising applications in biotechnology and biomedicine.

DNA hydrogel-empowered biosensing

“…Addition of adenosine induced aptamer deformation and separated the crosslinks and disassembled the gel. To provide a colorimetric signal, AuNPs were entrapped inside the gel that were released in the presence of adenosine [42,43]. In a similar work, a thrombin-binding aptamer was incorporated in the gel.…”

“…A) Mechanism of the thrombin responsive gel that incorporated EtBr to generate a fluorescent signal, adapted from ref. [43]. (B) Detection of AMP and ATP metabolites by disruption of the hybridization between DNA-functionalized gold nanoparticles and DNA-functionalized hydrogels followed by the release of gold nanoparticles resulting in the disappearance of the gel color, adapted from ref [44].…”

Morpholino Target Molecular Properties Affect the Swelling Process of Oligomorpholino-Functionalized Responsive Hydrogels

“…DNA-based responsive hydrogels are a promising group of materials capable of adapting their properties to the presence of various molecular targets in their environment, ranging from DNA [1][2][3] and other organic molecules [4][5][6], through ions [7][8][9][10] to viruses [11] and cells [12,13]. The mechanism of recognition relies on the ability to synthesize a custom DNA base sequence, which controls the structure of the DNA molecule down to the nanolevel, and on the Watson-Crick complementarity rules that govern the base pairing and interactions with other DNA or non-DNA (via aptamer interactions) molecules.…”

“…DNA thus offers remarkable sensitivity and specificity in its interactions and the hydrogel provides a means to amplify the molecular signal to a microscopic length scale. The possible applications are in sensing [4,10,14,15], targeted drug delivery [16][17][18], as well as in tissue engineering and as soft devices [1,[19][20][21].…”

Nanomaterial based aptasensors for clinical and environmental diagnostic applications

“…12,13 These receptors called aptamers (a term with Latin and Greek origins: aptus meaning t and meros meaning part) have shown notable moldable selectivity for diverse target analytes, ranging from small inorganic molecules, ions, sugars, proteins, and viruses to cells. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Such a varied target range is lacking in antibody generation due to the restriction of target receptor exposure in their native forms. This is more evident in whole cells where the surface antigens contain certain hidden trans-membrane regions, a fact which is generally not accounted for during the maturation of antibodies.…”