Advanced ELISA-like Biosensing Based on Ultralarge-Pore Silica Microbeads

Abstract

In this work, functionalized porous silica-based materials, widely used in the literature as drug and biomolecule nanocarriers, were innovatively used as an effective three-dimensional (3D) substrate for the development of a specific biomolecular assay showing great versatility in terms of detection performance. One-pot synthesis of ultralarge-pore silica microbeads was optimized to develop an enzyme-linked immunosorbent (ELISA)-like DNA detection assay. Cocondensation synthesis enabled introducing thiol functionalities into the silica framework while preserving both the high specific surface area (560 m 2 /g) and large pore size (17 nm average diameter), which are essential to guaranteeing high loading capability. Indeed, the bead-capturing ability was proved by developing an ELISA-like assay for the detection of short DNA sequences (≈20 bp), both in labeled and label-free configurations. In particular, the suppression of unspecific binding on the bead surface by testing two different blocking agents was a matter of interest. The detection performances were evaluated and compared to the ones obtained by following the same detection protocol on a standard flat surface (two-dimensional, 2D), which is most commonly used for this purpose. The bead-based assay showed a limit of detection two times lower than the flat-surface assay, confirming the promising capturing ability due to the larger active surface area. Furthermore, compared to traditional ELISA, the bead-based assay showed an intrinsic larger dynamic range that can be tailored depending on the final amount of beads used for the colorimetric quantification.

Recent Trends and Innovations in Bead-Based Biosensors for Cancer Detection

“…It enables the detection of cancer biomarkers, specifically nucleosomes and CEA, at concentrations as low as 62.5 and 15.6 pg/mL, respectively [23]. Ultralarge-pore silica microbeads are synthesized via a one-pot method with optimized condensation, this microbeads can be used as a versatile three-dimensional (3D) substrate for the development of an ELISA-like DNA detection, exhibiting superior bead-capturing ability and a two-fold lower LOD compared with a standard flat surface assay or traditional ELISA [102]. This kind of silica beads offer a stable and compatible surface for biomolecule immobilization and are used in various biosensing platforms for cancer-biomarker detection.…”

“…Using an ELISA-like approach, the mesoporous system effectively functions as the dispersed detection phase, demonstrating its capability to accurately measure DNA concentration within the range of 0-1 nM. Reprinted with permission from [102]. Copyright 2020 American Chemical Society.…”

Nanoarchitectured prototypes of mesoporous silica nanoparticles for innovative biomedical applications

“…In addition, the authors demonstrated that this label-free approach presented efficient, and self-signal amplifying detection, requiring no auxiliary labeling with ssDNA. Further, several efforts have been dedicated recently to exploring the applicability of DNA detection using these advanced prototypes of MSNs (Table 3 ) [ 402 – 404 ]. Despite the efficacy, in-depth analysis, and further improvements are significantly required as the fluorescence resonance energy transfer (FRET) procedure possessed similar sensitivity to that of the innovative metal-encapsulated MSNs.…”

Quantitation of Trastuzumab and an Antibody to SARS-CoV-2 in Minutes Using Affinity Membranes in 96-Well Plates

“…However, these kits typically require at least 2 h for analyses. Bead-based ELISAs and automated instrumentation enable such analyses in about 1 h, − although the techniques are labor-intensive or require specialized instrumentation. He et al recently developed miniaturized 96-well plates that require only 5 μL of the sample for each well and minimal equipment (a pipette and a magnet) .…”