Click and Detect: Versatile Ampicillin Aptasensor Enabled by Click Chemistry on a Graphene-Alkyne Derivative

Efficient Electrochemical Coupling of Aptamer to Nanoelectrode for In Situ Detection of ATP in Single Cells

Nanoelectrodes, renowned for their small size, rapid mass transport, fast response, and high spatiotemporal resolution, have been recognized as a powerful tool in biosensing, especially for single-cell analysis. However, the nanoelectrode itself has no selectivity and cannot respond to nonelectroactive substances, limiting its wide application to some extent. Herein, we propose a simple and efficient electrochemical conjugation strategy to develop an electrochemical aptamer-coupled (E-AC) sensor for detecting adenosine triphosphate (ATP) in single living cells. Through simple electrochemical conjugation, ferrocene-labeled aptamers could be stably and efficiently coupled onto the surface of carbon fiber electrodes within 5 min. The small size (ca. 400 nm) and biocompatibility of the functionalized nanoelectrodes enabled the E-AC sensors to noninvasively and continuously monitor ATP content in single HeLa cells over 20 min, as well as the cellular ATP fluctuations under glucose starvation. Furthermore, the E-AC sensors exhibit superior specificity, sensitivity, and universality in the application of analysis of ATP in single living Hela cells and MCF-7 cells. They were also versatile for sensing other nonelectroactive targets through modification of the corresponding electroactive marker-labeled aptamers, showing great potential in cell-related physiological processes and drug screening.

Aptamer-modified paper-based analytical devices for the detection of food hazards: Emerging applications and future perspective

Food analysis plays a critical role in assessing human health risks and monitoring food quality and safety. Currently, there is a pressing need for a reliable, portable, and quick recognition element for point-of-care testing (POCT) to better serve the demands of on-site food analysis. Aptamer-modified paper-based analytical devices (Apt-PADs) have excellent characteristics of high portability, high sensitivity, high specificity, and on-site detection, which have been widely used and concerned in the field of food safety. The article reviews the basic components and working principles of Apt-PADs, and introduces their representative applications detecting food hazards. Finally, the advantages, challenges, and future directions of Apt-PADs-based sensing performance are discussed, to provide new directions and insights for researchers to select appropriate Apt-PADs according to specific applications.

CdSSe Nano-Flowers for Ultrasensitive Raman Detection of Antibiotics

Surface-enhanced Raman scattering (SERS) technique is widely used for the highly sensitive detection of trace residues due to its unparalleled signal amplification ability and plays an important role in food safety, environmental monitoring, etc. Herein, CdSSe nano-flowers (CdSSe NFs) are synthesized via the chemical vapor deposition (CVD) method. CdSSe NFs thin film is used as a SERS substrate with an ultralow limit of detection (LOD, 10−14 M), high apparent enhancement factor (EF, 3.62 × 109), and excellent SERS stability (relative standard deviation, RSD = 3.05%) for probe molecules of Rh6G. Further, CdSSe NFs substrate is successfully applied in the sensitive, quantitative, and label-free analysis of ciprofloxacin (CIP) and enrofloxacin (ENR) antibiotics, which exhibit LODs of below 0.5 ppb. This excellent SERS platform may be widely utilized for sensitive life science and environmental sensing.