Aptamer-conjugated nanomaterials for specific cancer cell recognition and targeted cancer therapy

Abstract

Based on their unique advantages, increasing interest has been shown in the use of aptamers as target ligands for specific cancer cell recognition and targeted cancer therapy. Recently, the development of aptamer-conjugated nanomaterials has offered new therapeutic opportunities for cancer treatment with better efficacy and lower toxicity. We highlight some of the promising classes of aptamer-conjugated nanomaterials for the specific recognition of cancer cells and targeted cancer therapy. Recent developments in the use of novel strategies that enable sensitive and selective cancer cell recognition are introduced. In addition to targeted drug delivery for chemotherapy, we also review how aptamer-conjugated nanomaterials are being incorporated into emerging technologies with significant improvement in efficiency and selectivity in cancer treatment.

Keywords: aptamer; cancer therapy; cell recognition; nanomaterials.

Figure 1

Construction of fluorescent DNA nanodevices on target living cell surfaces based on an aptamer-tethered DNA nanodevice platform, where (a) three types of fluorescent DNA nanodevices, preformed via hybridization chain reaction (HCR)-based self-assembly upon initiation by aptamer-tethered trigger probes, are anchored on target cell surfaces, or (b) aptamer seed probes initiate in situ self-assembly of fluorescent DNA nanodevices on target cell surfaces by either (i) cascading alternative hybridization of two partially complementary monomers or (ii) HCR (adapted from Zhu et al.).

Figure 2

Schematic illustration of aptamer-micelle formation (a). Stepwise immobilization scheme of the flow channel (b). 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 (c), or FITC-library-micelle (d) or free FITC-TDO5 (e) spiked in a human whole-blood sample under continuous flow at 300 nl s⁻¹ at 37 °C for 5 min. All the scale bars are 100 μm (adapted from Wu et al.).

Figure 3

Synthesis and characterization of smart multifunctional nanostructures (SMNs). (a) Schematic illustration of the synthesis of SMNs. TEM images of (b) iron-magnetite core-shell nanoparticles (IMNPs), (c) hollow magnetite nanoparticles (HMNPs) and (d) porous hollow magnetite nanoparticles (PHMNPs). The inset of d shows an enlarged image of a representative PHMNP. The scale bars are 100 nm (10 nm for the inset). (e) Dispersibility of PHMNPs (left) and PEGylated PHMNPs (PPHMNPs; right) in hexane and water. (f) Fluorescence intensity of PPHMNPs and SMNs (excitation: 545 nm). (adapted from Chen et al.).

Figure 4

Schematic diagram illustrating the formation of an aptamer-functionalized core-shell nanogel (a). DNA sequences and linkages in the nanogel (b) (adapted from Kang et al.). Au-Ag NR, Au-Ag nanorod.

Figure 5

Working scheme of DNA aptamer circuit on cell membrane. (a) Scheme of the circuit without catalyst. (b) Scheme of the circuit on the cell membrane. (c) Scheme of detailed reaction of DNA hairpins A₁ and A₂ catalyzed by C sequence. Different domains are labeled with different colors. All x domains are complementary to x* (adapted from Han et al.).

Figure 6

Schematic diagram of aptamer-conjugated AuNR-Ce6 complex for targeted cancer therapy (adapted from Wang et al.).