Engineered Escherichia coli as a Controlled-Release Biocarrier for Electrochemical Immunoassay

Abstract

Micro/nanocarriers hold great potential in bioanalysis for molecular recognition and signal amplification but are frequently hampered by harsh synthesis conditions and timeconsuming labeling processes. Herein, we demonstrate that Escherichia coli (Ec) can be engineered as an efficient biocarrier for electrochemical immunoassay, which can load ultrahigh amounts of redox indicators and simultaneously be decorated with detection antibodies via a facile polydopamine (PDA)mediated coating approach. Compared with conventional carrier materials, the entire preparation of the Ec biocarrier is simple, highly sustainable, and reproducible. Moreover, immune recognition and electrochemical transduction are performed independently, which eliminates the accumulation of biological interference on the electrode and simplifies electrode fabrication. Using human epidermal growth factor receptor 2 (HER2) as the model target, the proposed immunosensor exhibits excellent analytical performance with a low detection limit of 35 pg/mL. The successful design and deployment of Ec biocarrier may provide new guidance for developing biohybrids in biosensing applications.

Target-Triggered Aggregation of Modified E. coli for Diagnosis of Ovarian Cancer

“…As a kind of microorganism, bacteria respond continuously to the external environment. − For the spectrum of bacterial behaviors, the bacterial surface layer assumes a pivotal role. − For example, functioning as the outermost barrier, the surface layer regulates bacterial shape, coordinates interactions with the environment, and shields prokaryotic cells from predators or phages. , Molecules on the surface layer predominantly govern bacterial interactions with the external environment . Moreover, modifications to the bacterial surface layer can artificially endow bacteria with many functions naturally unattainable. − There are commonly three modification methods. First, expressing certain specific protein or peptide tags through synthetic bioengineering has been the most common strategy .…”

An extracellular electron transfer enhanced electrochemiluminescence aptasensor for Escherichia coli analysis

“…17–19 The extracellular electron transfer (EET) process dominated by EAMs is critical for the survival and metabolism of these microorganisms, as well as for various biotechnological applications, such as energy generation, bioremediation, and biotechnology. 20–23 However, with the EET efficiency of traditional EAMs being low, many scholars have strengthened the electron transfer flux and efficiency through various disciplines. 24–26 It is usually achieved by using nano-engineered materials or biofilm-based systems, and plays an important role in microbial electrochemical technologies.…”

Controllable Assembly of a Quantum Dot-Based Aptasensor Guided by CRISPR/Cas12a for Direct Measurement of Circulating Tumor Cells in Human Blood

“…It should be noted that these strategies usually involve pre-amplification of nucleic acids and a subsequent cleavage reaction catalyzed by the activated Cas protein, , which is strongly dependent on the cleavage of high-cost fluorophore/quencher dual-modified reporter probes. Semiconductor quantum dots (QDs) have attracted more attention in the biosensing community due to their unparalleled optical and electronic properties (e.g., high brightness, narrow emission and broad absorption spectra, color tunability, and large surface-to-volume ratio). − The QDs can function as the centralized scaffolds in the assembly of multiple acceptor fluorophores, facilitating the construction of Förster resonance energy transfer (FRET)-based biosensors for the analysis of biomolecular interactions and various biomolecules. − Herein, we demonstrate the controllable assembly of a QD-based aptasensor for direct measurement of CTCs in human blood by integrating CRISPR/Cas12a-catalyzed generation of active primers with TdT-assisted template-free polymerization extension. This aptasensor can detect CTCs with high sensitivity and reliable accuracy.…”