**Abstract**

Optical fiber tweezers, as a versatile tool for optical trapping and manipulation, have attracted much attention in cell trapping, manipulation, and detection. Particularly, assembly of living cells using optical fiber tweezes has become a significant attention. Advanced achievements have been made on the assembly of fully biocompatible photonic probes with biological cells, enabling optical detection in biological environment in a highly compatible manner. Therefore, in this chapter, we discuss the use of optical fiber tweezers for assembly of living photonic probes. Living photonic probes can be assembled by the trapping and assembly of multiple cells using optical fiber tweezers. These photonic probes exhibit high biocompatibility and show great promise for the bio-applications in bio-microenvironments.

**Keywords:** Optical fiber tweezers, living photonic probes, optical trapping, optical manipulation, cell assembly

## **1. Introduction**

The development of optical fiber tweezers (OFTs) makes it a versatile candidate for optical trapping and manipulation of targets ranging from different dielectric particles to biological cells and biomolecules [1–3]. This is because OFTs possess exceptional advantages in manipulation flexibility, due to the simple structure with only optical fibers. This simple structure also avoids the use of a high numericalaperture objective which is necessary for the light focusing in conventional optical tweezers system [4, 5]. It is much easier to handle and manipulate the microscopic objects after trapped with OFTs [6, 7]. And it is much more suitable for practical use such as in trapping, levitating and rotating of microscopic particles in different environments [8–10]. The OFTs tip can be inserted into thick samples and turbid media, which greatly increases the sample applicability. In addition, OFTs exhibit a low-cost manipulation technique and can also be integrated into small devices, such as optofluidic channels [11]. OFTs enable the trapping and manipulation of different single targets. For the further biological detection in bio-environments, it is highly desired to form biocompatible photonic probes that can minimize the physical damage to the biological samples. Unfortunately, most photonic probes are made from inorganic and artificial materials, which are incompatible and invasive when interfacing with biological systems. It is still a big challenge to find out a biomaterial to assemble biophotonic probes that are noninvasive and highly biocompatible to

biological systems. Fortunately, it is found that living cells, which are abundant in the natural world, show the capability for light manipulation and propagation with high biocompatibility, and can thus be used for the assembly of living photonic probes. In this chapter, recent advances of OFTs in trapping and manipulating of cells, particularly in assembly of living photonic probes based on biological cells, were discussed. These formed living photonic probes provide a promising approach for bio-detection in biological environments with highly biocompatibility [12, 13].
