Aptamer-conjugated nanomaterials and their applications

Abstract

The combination of aptamers with novel nanomaterials, including nanomaterial-based aptamer bioconjugates has attracted considerable interest and has led to a wide variety of applications. In this review, we discuss how a variety of nanomaterials, including gold, silica and magnetic nanoparticles, as well as carbon nanotubes, hydrogels, liposomes and micelles, have been used to functionalize aptamers for a variety of applications. These aptamer functionalized materials have led to advances in amplified biosensing, cancer cell-specific recognition, high-efficiency separation, and targeted drug delivery.

Fig. 1

(A) Schematic representation of the ACGNP-based colorimetric assay. (B) Plots depicting the absorption spectra obtained for various samples analyzed using ACGNPs. The spectra illustrate the differences in spectral characteristics observed after the ACGNPs bind to the target cells. (Adapted from Ref. 38)

Fig. 2

Confocal microscopy images of individual NP-aptamer conjugates with three different cells (Toledo, CEM, and Ramos): (A) NP (FAM)-T1, (B) NP (FAM-R6G)-sgc8, and (C) NP (FAM-R6G- ROX)-TDO5. (Adapted from Ref. 55)

Fig. 3

Schematic representation of the multiple extraction procedure with the MNPs being added and extracted stepwise and the corresponding FNPs being added post-magnetic extraction of cell samples. (Adapted from Ref. 66)

Fig. 4

Schematic of an aptamer-photosensitizer-SWNT complex and the regulation of SOG upon target binding: (I) AP and SWNTs were mixed together to form an AP-SWNT complex. The ssDNA aptamer is wrapped on the surface of SWNTs, bringing the photosensitizer close to the SWNTs to quench SOG. (II) Target binding with aptamers disturbs the interaction between AP and SWNTs, resulting in the restoration of SOG. (Adapted from Ref. 76)

Fig. 5

Working principle and photograph of DNA cross-linked hydrogel for signal amplification and visual detection. In the absence of target, (A) shows enzyme (amylase) trapped inside gel on the bottom with substrate (amylose) separated on the top as a solution of the blue amylose–I₂ complex. (B) binding of aptamer with target (cocaine) induces gel dissolution and enzymatic reaction making the solution colorless. (Adapted from Ref. 86)

Fig. 6

Simplified flow channel response to cell-staining assay. (A). Stepwise immobilization scheme of the flow channel. Representative images of the bright field and fluorescent images of control cells (CCRF-CEM) and target cells (Ramos) captured on the flow channel surface incubated with FITC-TDO5-micelle (B), or FITC-library-micelle (C) or free FITC-TDO5 (D) spiked in human whole blood sample under continuous flow at 300 nL/s at 37°C for 5 m. All the scale bars are 100 μm. (Adapted from Ref. 108)