Highly sensitive protein detection via covalently linked aptamer to MoS₂ and exonuclease-assisted amplification strategy

Abstract

Molybdenum disulfide (MoS 2 ) has shown highly attractive superiority as a platform for sensing. However, DNA physisorption on the surface of MoS 2 was susceptible to nonspecific probe displacement and false-positive signals. To solve these problems, we have developed a novel MoS 2 –aptamer nanosheet biosensor for detecting thrombin using a covalently linked aptamer to the MoS 2 nanosheet. Ten percent Tween 80 was used to prevent thrombin from nonspecific binding and to rapidly form thiol-DNA/gold nanoparticle (AuNP) conjugates. Furthermore, an MoS 2 and exonuclease coassisted signal amplification strategy was developed to improve the detection limit for thrombin. We used the hybridization of the aptamer molecules and the matched strand with a 5′ terminal thiol to immobilize the aptamer molecules on the surface of AuNPs in AuNPs@MoS 2 nanocomposites. Exonuclease digested the single-strand aptamer and released the thrombin, which was then detected in the next recycle. With the coassisted amplification strategy, a 6 fM detection limit was achieved, showing that this method has higher sensitivity than most reported methods for thrombin detection. The results presented in this work show that this method of covalently attaching the aptamer and using the coassisted amplification is a promising technique for the detection of protein in medical diagnostics.

<p>Immunostimulatory Potential of MoS₂ Nanosheets: Enhancing Dendritic Cell Maturation, Migration and T Cell Elicitation</p>

“…The high near infrared ray absorbance, extraordinary electrocatalytic activity, easy surface modification and low biological toxicity make MSNs one of the most promising graphene analogues with wide applications in various fields, especially in nanobiomedicine. 2 To date, MSNs have been developed for use as bio-imaging probes, 3 biosensors, [4][5][6] photothermal therapy agents, [7][8][9] drug carriers [10][11][12] and tissue engineering scaffolds, 13 among other uses. The possibility of using MSNs as immuneregulatory adjuvants to manipulate the immune responses is also a very fascinating and a meaningful research topic.…”

Aptamer-Based Sensors for Thrombin Detection Application

“…In addition, exonuclease (Exo) catalyzed target circulation is also a common method of signal amplification [62]. Li et al, exploited a tactic for the aptamer-MoS 2 sensor based upon the strategy of fluorescence resonance energy transfer (FRET) to detect thrombin [63]. First, the double-stranded DNA (dsDNA) formed by TBA2 modified with carboxyfluorescein (FAM) and its complementary sequence modified with thiol group was immobilized on the Au nanoparticles (AuNPs) adsorbed on the surface of MoS 2 , and AuNPs@MoS 2 nanocomposites quenched the fluorescence of FAM.…”

“…Schematic representation of fluorescent sensors for thrombin detection. (A) The thrombin detection sensor based on aptamer controlling FITC release from mesoporous silicon nanoparticles.Adapted with permission from Ref [63]…”

Recent Developments in Carriers and Non-Aqueous Solvents for Enzyme Immobilization

“…They have been used in drug delivery, bioimaging, molecular sensing, gas and molecular separation, etc. [64][65][66][67]. Therefore, enzymes immobilized on MOFs have drawn increasing attention recently, and MOF materials such as zeolitic imidazolate framework-8 (ZIF-8), Tb-BDC, MIL-88, and HKUST-1 can maintain enzyme activity well [64,68]; for example, Candida antarctica lipase immobilized in B-IRMOFs has up to 1000-fold enhanced activity [69], and the activity of Cyt c embedded in ZIF-8 has been increased 10-fold [70].…”