Lab on a tip: Single-Cell manipulation within tissues using Noncontact Multiphysics Probe

Cells are minimal functional units in biological phenomena, and therefore single-cell analysis is needed to understand the molecular behavior leading to cellular function in organisms. The field of personalized medicine has steadily advanced through the elucidation of bulk tissue or fluid biomarkers, there is exciting potential for new discoveries if there are reliable techniques that are capable of identifying rare cell populations, associating cellular subsets with disease onset and/or treatment response. To achieve this, several methods such as micromanipulation and fluorescence-activated cell sorting method have been developed for single-cell isolation. Lately, thanks to advances in technology, these methods have incorporated microfluidic technologies that have improved their capability to manipulate operations due to the use of laminar flows, dielectrophoresis, microfluidic droplets as well as micro-and nanowells. For instance, these developments have provided more insights into DNA regulatory variations and genetic expressions. Unfortunately, while these techniques can resolve heterogeneity, they mainly contain the extraction of target cells from the tissues and thus lose the most important spatiotemporal resolutions used in the study of cellular networks. This can be partly attributed to the transient nature of most cellular processes like differentiation, proliferation and reprogramming. To this end, developing effective techniques with robust spatiotemporal profiling of cellular processes is urgent. This requires analyzing the single-cell dynamics in their natural physiological tissue environment, or in vitro tissue cultures, while retaining their spatial configurations.

To address these issues, Professor Mohammad A. Qasaimeh and his team from New York University Abu Dhabi designed a noncontact multiphysics probe (NMP) that can be accurately controlled for genetical manipulation and analysis of living single-cells within their natural physiological environment. Being a multifunctional tool combining contactless scanning probes, electropermealization and hydrodynamic flow confinement concepts, NMP can effectively achieve spatiotemporal resolved single-cell manipulation. It consisted of bump-shaped electrodes and fluidic apertures that simultaneously confined the electrical signals and reagents within the single-cell resolution to facilitate the manipulation operations while maintaining the spatial configurations of the cellular networks. The NMP’s spatial adjustable capability was evaluated by transfecting single-cells with different DNA plasmid vectors, enabling the characterization of the cell molecular transfer response in their adherent state. The original research article is now published in the research journal, Small.

The research team demonstrated the ability of the newly proposed NMP technology to perform a wide range of multiphysics-based single-cell manipulation and analysis with high precision. It also retained the spatial configurations of the living cells within their tissue culture, which also played a significant role in improving the study of their native heterogeneity. Its application for noncontact transfer of extracellular macromolecules was successfully demonstrated, and it displayed target macromolecule delivery in precise patterns. Similarly, the authors characterized electropermeabilization of the cells within their adherent state and discovered new insights into the influence of electropermeabilization on the cell morphology, which is relevant for electro-chemotherapy studies. Remarkably, the findings also showed that NMP could be used to perform controllable extraction of cytoplasm from adherent living single-cells, within their tissue culture arrangement, and without interfering with the cell viability or the integrity of the extracted RNA.

In a statement to Advances in Engineering, Dr. Ayoola T. Brimmo, the first author of the study said “This is synonymous to collecting blood samples from a patient without any physical contact between the needle and the skin — however, in the case of the NMP, the patient is a single mammalian cells, and the “needle” is the tiny NMP that uses electrical signals to puncture through the cell membrane invasively.

In summary, the authors successfully developed a new NMP technology with multiple spatiotemporal resolved capabilities for noncontact single-cell manipulation and analysis. Its remarkable performance was attributed to its unique properties that allowed for simultaneous confining of electric fields and reagents to single-cells within their tissue culture. This technology is an invaluable tool for collecting subcellular compartments of single-cell targets and could benefit organ development processes. Additionally, NMP can aid heat-driven enzymic dissociation of single-cells for accurate genomic expression assays. In a statement to Advances in Engineering, Professor Qasaimeh, the corresponding author said the newly innovative technique offers an invaluable tool for precise spatiotemporal single-cell manipulation and analysis, which will significantly contribute to advance research in cell biology. He further added that their current efforts are focused toward increasing the tool’s experimental throughput and precision, for enabling deeper insights on the fundamental internal workings of cells.