Self-assembled GA-Repeated Peptides as a Biomolecular Scaffold for Biosensing with MoS₂ Electrochemical Transistors

Abstract

Biosensors with two-dimensional materials have gained wide interest due to their high sensitivity. Among them, single-layer MoS2 has become a new class of biosensing platform owing to its semiconducting property. Immobilization of bioprobes directly onto the MoS2 surface with chemical bonding or random physisorption has been widely studied. However, these approaches potentially cause a reduction of conductivity and sensitivity of the biosensor. In this work, we designed peptides that spontaneously align into monomolecular-thick nanostructures on electrochemical MoS2 transistors in a non-covalent fashion and act as a biomolecular scaffold for efficient biosensing. These peptides consist of repeated domains of glycine and alanine in the sequence and form self-assembled structures with sixfold symmetry templated by the lattice of MoS2. We investigated electronic interactions of self-assembled peptides with MoS2 by designing their amino acid sequence with charged amino acids at both ends. Charged amino acids in the sequence showed a correlation with the electrical properties of single-layer MoS2, where negatively charged peptides caused a shift of threshold voltage in MoS2 transistors and neutral and positively charged peptides had no significant effect on the threshold voltage. The transconductance of transistors had no decrease due to the self-assembled peptides, indicating that aligned peptides can act as a biomolecular scaffold without degrading the intrinsic electronic properties for biosensing. We also investigated the impact of peptides on the photoluminescence (PL) of single-layer MoS2 and found that the PL intensity changed sensitively depending on the amino acid sequence of peptides. Finally, we demonstrated a femtomolar-level sensitivity of biosensing using biotinylated peptides to detect streptavidin.

Two-Dimensional Layered Nanomaterials Steering Self-Assembly of Dodecapeptides with Three Building Blocks

“…20−22 In contrast to such covalent modification, the peptide self-assembly through physicochemical interactions not only enables to remain the structural integrities of the solid surface but also bestows a method of creating long-range ordered nanopatterns to functionalize the underlying substrates and serve as a scaffold for the immobilization of probe biomolecules. 3,23 Therefore, peptide-based hybrid bionanomaterials via physicochemical interactions, recently, have found wide applications in nanodevices of 2D materials.…”

“…Self-assembly of peptides on solid surfaces through the bottom-up technique, enabling to form long-range ordered two-dimensional (2D) nanocrystal patterns leading to its potential applications for biosensing, − bioelectronics, , and surface coating, − has attracted significant interest in nanoscience and nanotechnology. The accurate formation of nanostructural arrays from smallest unit cells, through molecule-by-molecule lengthening and row-by-row widening in longitudinal and lateral directions, to microscale nanowire (NW) patterns offers insight into the fundamental studies on fibrilizations of amyloid beta peptides, toward understanding the cause of neurodegenerative diseases such as Alzheimer's disease, − and toward providing an available strategy for application in the semiconductor industry. − Generally, self-assembly of synthetic molecules on solid surfaces forming a molecular monolayer is completed via simple chemical binding or say covalent interaction, rather than a physicochemical interaction in the case of peptide–solid surfaces.…”

“…The accurate formation of nanostructural arrays from smallest unit cells, through molecule-by-molecule lengthening and row-by-row widening in longitudinal and lateral directions, to microscale nanowire (NW) patterns offers insight into the fundamental studies on fibrilizations of amyloid beta peptides, toward understanding the cause of neurodegenerative diseases such as Alzheimer's disease, − and toward providing an available strategy for application in the semiconductor industry. − Generally, self-assembly of synthetic molecules on solid surfaces forming a molecular monolayer is completed via simple chemical binding or say covalent interaction, rather than a physicochemical interaction in the case of peptide–solid surfaces. The chemical binding method allows the functionalization of the solid surfaces while lowering the innate performance of the solid surface such as electronics or optics due to structural damages, , especially for the emergence of various single-layer 2D nanomaterials such as graphene, MoS 2 , and WSe 2 . − In contrast to such covalent modification, the peptide self-assembly through physicochemical interactions not only enables to remain the structural integrities of the solid surface but also bestows a method of creating long-range ordered nanopatterns to functionalize the underlying substrates and serve as a scaffold for the immobilization of probe biomolecules. , Therefore, peptide-based hybrid bionanomaterials via physicochemical interactions, recently, have found wide applications in nanodevices of 2D materials.…”

Protein-Assisted Molybdenum Disulfide as Biomimetic Nanozyme for Antibacterial Application

“…Organic compounds including small molecules and polymers process tunable molecular structures, which can induce chemical bonding or physical interactions. − Among them, biomolecules are biocompatible. Their charged groups or active groups can form complexes with molybdenum disulfide to modify their surface properties. − Derived from the objective biological application, the synthesis and modification of molybdenum disulfide can be assisted by biomolecules, paving their way as biomimetic nanozymes.…”

Amplified detection of SARS‐COV‐2 B.1.1.529 (Omicron) gene oligonucleotides based on exonuclease III‐aided MoS2/AIE nanoprobes

“…Among them, 2-(3-cyano-5,5-dimethyl-4-(4-[1,2,2-triphenylvinyl]styryl)furan-2(5H)ylidene)malononitrile (TPE-TCF) (TPET) possesses typical aggregation-induced emission (AIE)-features, with four benzene rings as free rotors providing sufficient motion [12,17]. Besides, new types of acceptors, such as two-dimensional (2D) nanomaterials with unique optical quenching ability and large surface area for biomolecules interacting were highly concerned in recent studies [18,19]. Among them, MoS 2 nanosheets with excellent biocompatibility and nanoscale-surface energy transfer effect have emerged as candidates [20][21][22].…”