Preparation of Aptamer Responsive DNA Functionalized Hydrogels for the Sensitive Detection of α-Fetoprotein Using SERS Method

Abstract

Hepatocellular carcinoma (HCC), which is one of the three major cancers, has attracted growing attention due to its high mortality, health care cost, and circumscribed therapeutic methods. Hence, the development of a fast, accurate, and flexible method to detect α-fetoprotein (AFP), the specific marker of HCC, is significant for diagnosis and treatment of cancer. Here, we constructed a novel SERS biosensing platform combining the target-responsive DNA hydrogel for the sensitive detection of AFP. The linker strand in DNA hydrogel is an aptamer that can specifically recognize AFP and accurately control the release of immunoglobulin G (IgG) encapsulated in hydrogel. In the presence of AFP, the hydrogels were disentangled and the IgG was released. Thereafter, the released IgG was captured by SERS probes and biofunctional magnetic beads through formation of sandwich-like structures, resulting in the signal of Raman tags decreasing in the supernatant after magnetic separation. Due to the ultrahigh sensitivity of the SERS biosensor, the proposed method has a wide detection linear range (50 pg/mL to 0.5 μg/mL) and a detection limit down to 50 pg/mL. Moreover, the sequence of the linker strand in the DNA hydrogel can be specifically encoded into a new aptamer that responds to other cancer markers. This convenient and inexpensive detection method provides a new strategy for the detection of tumor markers.

Towards practical and sustainable SERS: a review of recent developments in the construction of multifunctional enhancing substrates

“…The surface of SERS enhancing nanomaterials can also be functionalized with a self-assembled monolayer of biomolecules, in particular aptamers and antibodies, which selectively capture target analytes mixed within complex samples. [168][169][170][171] To introduce the sample and facilitate target recognition the functionalized enhancing particles are typically used in combination with carefully designed paper substrates to form separation-enhancement-in-one lateral flow assay platforms. 134,[172][173][174] For example, Wang and Wang, et al designed a lateral flow assay platform which utilized SERS active magnetic nanoparticles for rapid simultaneous detection of two respiratory viruses, influenza A (H1N1) and human adenovirus (HAdV), in real biological samples, as illustrated in Figure 11D.…”

Design, Bioanalytical, and Biomedical Applications of Aptamer-Based Hydrogels

“…Because the binding affinities of aptamers to their target analytes are much stronger than that of simple hybridization, the network structure may deform or disintegrate when the specific target analytes are presented. The deformation of the aptamer-based hydrogel network can be easily detected with naked eyes or various colorimetric or fluorescence agents including, silver, gold nanoparticles, iodine, fluorescent dyes, and quantum dots (83,(100)(101)(102)(103)(104)(105)(106)(107). The constructed hydrogel biosensor may achieve visual detection easily.…”

“…The ultra-trace aptamer DNA hydrogel (0.01 ml) detected cocaine directly with a low detection limitation (1.17 nM) and excellent selectivity as ( Figure 1B). A novel SERS biosensing platform was constructed by combining the targetresponsive DNA hydrogel for the sensitive detection of αfetoprotein (AFP) (83). The aptamer as a linker strand in DNA hydrogel specifically recognized AFP and accurately controlled the release of immunoglobulin G (IgG) encapsulated in hydrogel.…”

Recent Advancements in Aptamer-Based Surface Plasmon Resonance Biosensing Strategies

“…Consequently, by incorporating these nucleic acid aptamers into various sensing platforms, it is possible to subject these probes to repeated use without loss of functionality, thereby allowing a device to be potentially recyclable. Numerous aptamer-based approaches have been reported for chemical and biological detection, such as surface-enhanced Raman spectroscopy [40,41], SPR [42,43], fluorescence [44,45], colorimetry [46,47], and electrochemistry [48,49].…”