CXCL12 and neoplasm: They demonstrated the dynamic process of Ag2S QD‐labelled MSC biodistribution and homing in response to SDF‐1α on the cutaneous wound healing.94 Considering high sensitivity and resolution at the cellular level for optical imaging in the SWIR region, researchers also can evaluate the tumour cell deposits in its early stages in addition to monitoring of the dynamic cellular behaviour.150, 151 For this reason, Tao et al have investigated the growth of the tumour in the early stage in the small animal model.