Sensors and Actuators Reports最新文献

Recombinant adeno-associated viruses (rAAVs) are promising vectors for gene therapy, but their production is hampered by the presence of empty capsids, escalating costs and diminishing safety and efficacy. Traditional methods for assessing capsid content status lack adaptability to in-line production workflows. The lack of in-line methods to monitor rAAV production quality limits efforts seeking to improve production efficiency and subsequent in vivo performance. This study introduces a dual in-plane nanopore sensor fabricated in thermoplastics via replication, which can offer near real-time sensing for potential integration into gene therapy production lines and scalability for high-scale manufacturing at low cost. By leveraging differences in surface charge density and internal capsid content, coupled nanoscale electrophoresis and resistive pulse sensing enabled label-free identification of individual full and empty capsids using supervised machine learning with a neural network. This single-capsid analysis approach may also offer insights into rAAV-host cell interactions and population heterogeneity. We demonstrated using rAAV9 as an example due to its wide use in gene therapies, but establishment of the methodology as delineated in this manuscript will make the technology applicable to other vectors, such as lentiviruses and adenoviruses.

Electroanalysis is a type of analytical method used to study an analyte by measuring its electrical properties in an electrochemical cell. It has been widely used because it is a relatively simple and inexpensive technique, has a low detection limit and is able to measure original electrical signals. Electroanalysis has advanced with the development of nanotechnology, offering new opportunities for analysis. Scanning electrochemical microscopy (SECM) is a probe-based surface analysis instrument that enables real-time surface and interfacial analysis with spatial resolution in an electrochemical environment. In this review, we focus on the use of nanoscale SECM for improved electroanalysis. After introducing the fabrication, characterization, and modification of nanoelectrodes, which are the key to enabling nanoscale SECM, we introduce the instrumentation and fundamental principles of SECM. Several examples are provided to illustrate the advanced electroanalysis of photo-electrocatalysts and biosystems based on nanoscale SECM, which will be utilized as a more powerful electroanalytical tool in the future when combined with other analytical instruments.

Microplastics (MPs) are global pollutants found in various environmental compartments, including oceans, freshwater bodies, soils, and air. Their persistence and potential to adsorb heavy metals raise significant concerns regarding water quality and ecosystem health. Understanding the interaction between MPs and heavy metals is crucial for assessing environmental risks and developing remediation strategies. In this study, we use electroanalytical techniques to investigate the adsorption of heavy metal ions— Cr³⁺, Zn²⁺, and Ni²⁺—by polystyrene MPs with different surface functionalizations: carboxyl, amino, and unfunctionalized. We conducted electrodeposition of metal ions on a gold ultramicroelectrode both before and after mixing with MPs. Following this, we used anodic stripping voltammetry to measure the change in the electrodeposited charge (ΔQ). This charge difference, observed before and after the interaction of ions with MPs, was analyzed to understand the adsorption kinetics and dynamics. Our experiments revealed that carboxyl-functionalized MPs exhibited the highest ΔQ due to strong electrostatic attraction with the metal ions, with values 1.67 ×, 1.50 ×, and 1.22 × greater than those for amino-MPs for Cr³⁺, Zn²⁺, and Ni²⁺, respectively. Amino-MPs displayed considerable ion adsorption, suggesting poor electrostatic repulsion between two positively charged entities. Interestingly, unfunctionalized MPs, which had a negative surface charge similar to carboxyl-MPs, showed different adsorption characteristics, with lower ΔQ values for all metal ions. This study underscores the significant role of surface functionalization on the adsorption efficiency and kinetics of heavy metal ions by MPs. It also demonstrates the utility of electroanalytical techniques in understanding metal ion-MP interactions, offering insights into potential environmental impacts and remediation strategies, as well as in developing electrochemical sensors for detecting heavy metal ions adsorbed on MPs.