Advanced Nanoscale Approaches to Single-(Bio)entity Sensing and Imaging

Abstract

Individual (bio)chemical entities could show a very heterogeneous behaviour under the same conditions that could be relevant in many biological processes of significance in the life sciences. Conventional detection approaches are only able to detect the average response of an ensemble of entities and assume that all entities are identical. From this perspective, important information about the heterogeneities or rare (stochastic) events happening in individual entities would remain unseen. Some nanoscale tools present interesting physicochemical properties that enable the possibility to detect systems at the single-entity level, acquiring richer information than conventional methods. In this review, we introduce the foundations and the latest advances of several nanoscale approaches to sensing and imaging individual (bio)entities using nanoprobes, nanopores, nanoimpacts, nanoplasmonics and nanomachines. Several (bio)entities such as cells, proteins, nucleic acids, vesicles and viruses are specifically considered. These nanoscale approaches provide a wide and complete toolbox for the study of many biological systems at the single-entity level.

Nanoscale Electrochemical Mapping

“…16 The popularity of SECM, in particular, and SEPM in general, for single cell electrochemical imaging and life sciences applications, is reflected in a number of recent review articles. [17][18][19][20][21][22] SEPM is a key enabling technology for the emerging fields of single entity electrochemistry and electrochemistry at nano-interfaces, for which there were seminal Faraday Discussion meetings in 2016 and 2018, respectively. The published volumes of these meetings 23, 24 contain not only original papers, but also extensive discussions of key issues.…”

Electrochemical Detection and Characterization of Nanoparticles with Printed Devices

“…Electrochemical detection of nanoparticles by the nanoimpact method [120,121] is an emergent strategy for the characterization and quantification of individual nanoparticles and even enables the detection of single entities of biochemical species [122]. This method entails the stochastic detection of particles colliding against an electrode surface, providing information about individual entities instead of average ensembles of particles, such as in the conventional methods previously described.…”

“…Different electrochemical strategies to detect collisions of individual nanoparticles and the typical stochastic amperometric response recorded when nanoparticles collide with the electrode. Adapted with permission (CC BY 4.0 license) from [122] MDPI.…”

P-N Junction-Based Si Biochips with Ring Electrodes for Novel Biosensing Applications

“…Thus, the biochips can be helpful for the disease diagnosis with high reliability and time efficiency. Biochips possess many advantages such as mass production, simple immobilization, high density, and high throughput [3].…”