Mixed Self-Assembled Aptamer and Newly Designed Zwitterionic Peptide as Antifouling Biosensing Interface for Electrochemical Detection of alpha-Fetoprotein

Abstract

A sensitive and low-fouling aptasensor for alpha-fetoprotein (AFP) was developed based on mixed self-assembled aptamers and newly designed zwitterionic peptides, where densely immobilized peptides formed an antifouling layer to resist nonspecific protein adsorption, and sparsely attached aptamers acted as the recognizing layer to achieve target binding. The obtained biosensing interface responded to the target AFP with a strikingly selective and sensitive manner, exhibited excellent protein-resistant performance even in complex human serum solution, and showed promising feasibility for the quantitative analysis of AFP in real human serum samples.

Antifouling (Bio)materials for Electrochemical (Bio)sensing

“…Peptides are prospective candidates among antifouling materials because, apart from their ease design and synthesis, they are composed of natural amino acids which are zwitterionic molecules in biological systems and, therefore, possess inherently outstanding biocompatibility [36]. Besides superior biocompatibility and coordination ability, particularly designed peptides with strong hydrophilicity and neutral charge [37,38,39] help to prevent nonspecific protein adsorption through hydrophobic interaction and charge attraction, respectively [5,6].…”

“…Cui et al [6] reported a low-fouling aptasensor for the determination of alpha-fetoprotein (AFP) using mixed self-assembled aptamers and newly designed zwitterionic peptides. The long-chained AFP-specific aptamers acted as the recognizing layer and the designed short-chained zwitterionic peptides (with good hydrophilicity, nearly electrical neutrality) endowed biocompatibility and antifouling ability against nonspecific protein adsorption.…”

“…Schematic illustration of antifouling aptasensing interfaces developed through self-assembly of zwitterionic peptides and the specific aptamers for ( a ) alpha-fetoprotein (AFP) determination onto a gold electrode and ( b ) IgE onto a macroporous Au substrate electrochemically fabricated on a GCE. Reprinted from (a) [6] and (b) [5] with permission.…”

“…However, most antifouling strategies involve the use of a modified electrode with improved fouling resistance than the nonmodified electrode. Efficient efforts to minimize surface (bio)fouling have focused mainly on constructing antifouling biosensing electrochemical interfaces by using materials such as polymers, hydrogels, peptides, and thiolated self-assembled monolayers (SAMs) [5,6].…”

Beyond Sensitive and Selective Electrochemical Biosensors: Towards Continuous, Real-Time, Antibiofouling and Calibration-Free Devices

“…Although these are considered as the “gold standard” materials, they show various defects such as their oxidative damage, poor water-solubility, and low protein resistance at high temperature. Peptides have come up as possible alternative antifouling materials in electrochemical affinity biosensors [ 30 , 31 , 32 ], providing additional advantages of biocompatibility, tunable and simple structure and synthesis [ 24 ].…”