Characterisation of aptamer-anchored poly(EDMA-co-GMA) monolith for high throughput affinity binding

Abstract

Immobilisation of aptameric ligands on solid stationary supports for effective binding of target molecules requires understanding of the relationship between aptamer-polymer interactions and the conditions governing the mass transfer of the binding process. Herein, key process parameters affecting the molecular anchoring of a thrombin-binding aptamer (TBA) onto polymethacrylate monolith pore surface, and the binding characteristics of the resulting macroporous aptasensor were investigated. Molecular dynamics (MD) simulations of the TBA-thrombin binding indicated enhanced Guanine 4 (G4) structural stability of TBA upon interaction with thrombin in an ionic environment. Fourier-transform infrared spectroscopy and thermogravimetric analyses were used to characterise the available functional groups and thermo-molecular stability of the immobilised polymer generated with Schiff-base activation and immobilisation scheme. The initial degradation temperature of the polymethacrylate stationary support increased with each step of the Schiff-base process: poly(Ethylene glycol Dimethacrylate-co-Glycidyl methacrylate) or poly(EDMA-co-GMA) [196.0 °C (±1.8)]; poly(EDMA-co-GMA)-Ethylenediamine [235.9 °C (±6.1)]; poly(EDMA-co-GMA)-Ethylenediamine-Glutaraldehyde [255.4 °C (±2.7)]; and aptamer-modified monolith [273.7 °C (±2.5)]. These initial temperature increments reflected in the associated endothermic energies were determined with differential scanning calorimetry. The aptameric ligand density obtained after immobilisation was 480 pmol/μL. Increase in pH and ionic concentration affected the surface charge distribution and the binding characteristics of the aptamer-modified disk-monoliths, resulting in the optimum binding pH and ionic concentration of 8.0 and 5 mM Mg2+, respectively. These results are critical in understanding and setting parametric constraints indispensable to develop and enhance the performance of aptasensors.

Translational control of enzyme scavenger expression with toxin-induced micro RNA switches

“…Most of the recent approaches use an aptamer element to engineer ligand-responsiveness and to regulate gene expression [23][24][25][26]44 . Aptamers are widely used, due to their high binding affinity against their respective target and their specificity [70][71][72][73][74][75][76][77][78][79][80][81][82] . In principal, the process of SELEX (Systematic Evolution of Ligands by Exponential enrichment) allows aptamer selection against any small molecule of interest 83,84 .…”

Neuroblastoma GD2 Expression and Computational Analysis of Aptamer-Based Bioaffinity Targeting

“…This method combines the principles of cytology with the specificity of immunological reactions to perform localization and/or quantification of cells with antigens of interest. In other words, the method thrives on the presence and development of antibodies or other high-affinity agents such as aptamers [51,52]. Although aptamers promise to overcome some of the limitations associated (in terms of selection difficulties, selectivity problems, preparation difficulties, high costs of production, stability, and cross-reactivity issues), there is little to no research reports on their application for GD2 characterization.…”

“…Aptamers are single-stranded oligonucleotides (RNA or DNA) capable of binding to specific target molecules [52,60]. Its application in the detection and treatment of several types of malignancy has been studied extensively with impressive results in binding specificities to various types of small molecules including antigens and toxins [61][62][63][64].…”

Optimisation of a gold nanoparticle-based aptasensor integrated with image processing for the colorimetric detection of acephate using response surface methodology

“…49 Moreover, molecular interactions between aptamers and their target molecules are affected by physicochemical conditions of the binding environment, including both ionic concentration and pH. 45,[50][51][52][53][54][55] Li et al (2021) developed a label-free target binding induced aptamer structure switch colorimetric sensor for ultrasensitive detection of kanamycin based on Exo Iassisted signal amplication and polycationic protamine mediated aggregation of negatively charged AuNPs with a low detection limit of 2.8 Â 10 À14 M under optimal conditions. 44 Besides that, many studies have used AuNPs based aptasensors for the detection of OPs, which resulted in notable low limits of detection (LOD).…”