Surface plasmon resonance biosensor using hydrogel-AuNP supramolecular spheres for determination of prostate cancer-derived exosomes

Evolution of Supramolecular Systems Towards Next-Generation Biosensors

“…Three general detection schemes, particularly for sensing systems that generate optical read-outs are the following: 1) direct sensing, whereby a signal output is generated upon the direct binding of an analyte to the receptor (Figure 2A); 2) indicator displacement, which involves the signal change upon the displacement of an indicator by an analyte from the sensory unit (Figure 2B); and 3) aggregation/disaggregation of sensory units in the presence of absence of the analyte (Figure 2C,D). The low energy barrier for disassembly and reassembly of supramolecular structure (Li J. et al, 2020), specifically those that are based on aggregates held by π-π interactions, also support good signal amplification. Curently available supramolecular materials have been made from inorganic systems, organic structures, polymers, hybrid materials, charged molecules, crystals, gels, metallic nanoparticles, and others by combining various types of non-covalent interactions (Martins et al, 2015;Wang et al, 2016).…”

“…This phenomenon occurs when the polarized light is reflected on the surface of metal at the interface of two media at a certain angle ( Figure 4C ). For example, Chen et al used a hydrogel-gold nanoparticle supramolecular sphere to develop a label-free and real-time SPR imaging biosensor and specifically detect prostate cancer cell-derived exosomes ( Chen et al, 2020 ). DNA probes on the gold chip surface modified with antibodies can capture the targets by forming polymers.…”

“…Other biosensors depend on conjugated aromatic compounds known as aggregation-induced emission luminogens (AIEgens), which often consist of flexible molecular moieties that can consume the energy of the excited state upon photoexcitation through intramolecular motion in the dispersed state. The fluorescence of AIEgens can be attributed to the restriction of intermolecular motion (Li J. et al, 2020). Supramolecular materials based on AIEgens could result in high luminescence efficiency and can be constructed easily to (Sierra et al, 2020).…”

“…give controlled and tunable architectures (Li J. et al, 2020). Tang and co-workers reported the first AIEgen using tetraphenylethylene (TPE) as the supramolecular reporter unit (Hong et al, 2008).…”

Surface Plasmon Resonance Biosensor for Sensitive Detection of HER2-positive Exosomes Based on Reformative Tyramine Signal Amplification Activated by Molecular Aptamer Beacon Conversion

“…So far, apart from traditional methods including nanoparticle tracking analysis, western blot, ow cytometry, and enzyme-linked immunosorbent assay [11], various biosensing platforms have been developed for exosomes analysis by targeting their surface proteins using the corresponding antibodies or aptamers [12][13][14][15][16][17]. Among them, surface plasma resonance (SPR) biosensor is receiving extensive attention because it is a rapid, real-time, and label-free diagnostic device [18,19]. The sensing principle of this technique is to measure the change in refractive index around the surface of the metallic sensor chip due to alterations in mass caused by analyte-receptor noncovalent interactions [20,21].…”