Single-Cell Biodetection by Upconverting Microspinners

This is the peer reviewed version of the following article: Ortiz‐Rivero, E., Prorok, K., Skowickł, M., Lu, D., Bednarkiewicz, A., Jaque, D., & Haro‐González, P. (2019). Single‐Cell Biodetection by Upconverting Microspinners. Small, 15(46), 1904154, which has been published in final form at https://doi.org/10.1002/smll.201904154. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsNear-infrared-light-mediated optical tweezing of individual upconverting particles has enabled all-optical single-cell studies, such as intracellular thermal sensing and minimally invasive cytoplasm investigations. Furthermore, the intrinsic optical birefringence of upconverting particles renders them light-driven luminescent spinners with a yet unexplored potential in biomedicine. In this work, the use of upconverting spinners is showcased for the accurate and specific detection of single-cell and single-bacteria attachment events, through real-time monitoring of the spinners rotation velocity of the spinner. The physical mechanisms linking single-attachment to the angular deceleration of upconverting spinners are discussed in detail. Concomitantly, the upconversion emission generated by the spinner is harnessed for simultaneous thermal sensing and thermal control during the attachment event. Results here included demonstrate the potential of upconverting particles for the development of fast, high-sensitivity, and cost-effective systems for single-cell biodetectionThis work was partially supported by the Ministerio de Economía y Competitividad de España (MAT2016‐75362‐C3‐1‐R) and by the Instituto de Salud Carlos III (PI16/00812), by the Comunidad Autónoma de Madrid (B2017/BMD‐3867RENIMCM), and cofinanced by the European Structural and investment fund Additional funding was provided by COST action CM1403. D.L. thanks the Chinese Scholarship Council for financial support. K.P. acknowledges the support from Foundation for Polish Science (FNP) under START program. A.B. acknowledges financial support from NCN OPUS DEC‐2017/27/B/ST7/01255 gran