All-Fibre Label-Free Nano-Sensor for Real-Time in situ Early Monitoring of Cellular Apoptosis

TL;DR

This paper introduces a compact, all-fibre, label-free nano-sensor that enables real-time, in situ monitoring of cellular apoptosis with high sensitivity, minimal cytotoxicity, and potential applications in cell biochemistry research.

Contribution

The study presents a novel all-fibre nano-sensor combining a fibre taper and zinc oxide nano-gratings for long-term, label-free cellular monitoring, advancing in situ cell analysis techniques.

Findings

Detected gradual increase in nuclear refractive index during apoptosis

Demonstrated high sensitivity and minimal cytotoxicity of the sensor

Enabled long-term in situ tracking of cellular apoptosis

Abstract

The achievement of all-fibre functional nano-modules for subcellular label-free measurement has long been pursued due to the limitations of manufacturing techniques. In this paper, a compact all-fibre label-free nano-sensor composed of a fibre taper and zinc oxide nano-gratings is designed and applied for the early monitoring of apoptosis in single living cells. Because of its nanoscale dimensions, mechanical flexibility and minimal cytotoxicity to cells, the sensing module can be loaded in cells for long-term in situ tracking with high sensitivity. A gradual increase in the nuclear refractive index during the apoptosis process is observed, revealing the increase in molecular density and the decrease in cell volume. The strategy used in this study not only contributes to the understanding of internal environmental variations during cellular apoptosis but also provides a new platform for non-fluorescent all-fibre devices to investigate cellular events and to promote new progress in fundamental cell biochemical engineering.