Traditionally, CNPs directly obtained from nanosecond pulsed laser ablation (ns-PLA) in an organic solvent like ethanol, isopropyl alcohol and acetone, possess toxic characteristics with excellent fluorescent properties. However, water-soluble CNPs are found to be non-toxic with weak fluorescent properties. In this study, a post-ablation method was utilized to achieve water-soluble fluorescent CNPs. Initially, the colloidal Eth-CNPs solution was obtained from ns-PLA of charcoal powder in the ethanol, which was subsequently dried at room temperature and then dispersed in water to achieve the final water-soluble CNPs (W-CNPs). The High-resolution Transmission Electron Microscopy (HRTEM) image analysis of W-CNPs shows quasi-spherical size particle distribution with an average particle size found to be around 21 nm. XPS studies of charcoal powder and W-CNPs confirm the creation of fluorescent emissive defects state on the surface of W-CNPs under laser ablation in ethanol. Photoluminescence studies of W-CNPs demonstrated the wavelength-dependent PL emission, with peak PL emission in the blue region of the visible spectrum. In vitro studies indicated the non-toxic nature of the W-CNPs at low and high concentration (1, 5 and 10% v/v) in human cardiomyocytes. Herein, the W-CNPs obtained from post-ns-PLA was found to exhibit both blue and green fluorescence in the cardiomyocytes and hence, it can be exploited as a fluoro probe in bioimaging applications.

传统上，由纳秒脉冲激光烧蚀（ns-PLA）直接在有机溶剂（如乙醇，异丙醇和丙酮）中获得的CNP具有毒性和荧光特性。然而，发现水溶性CNP是无毒的，具有弱的荧光性质。在这项研究中，后消融方法被用来实现水溶性荧光CNP。最初，从乙醇中木炭粉的ns-PLA获得胶体Eth-CNPs溶液，随后将其在室温下干燥，然后分散在水中以得到最终的水溶性CNP（W-CNPs）。W-CNP的高分辨率透射电子显微镜（HRTEM）图像分析显示了准球形粒径分布，平均粒径约为21 nm。对木炭粉和W-CNPs的XPS研究证实，在乙醇中进行激光烧蚀后，W-CNPs表面产生了荧光发射缺陷状态。W-CNP的光致发光研究表明，波长依赖的PL发射，在可见光谱的蓝色区域具有峰值PL发射。体外研究表明，低浓度和高浓度（1、5％和10％v / v）的W-CNP对人心肌细胞无毒。在此，发现从ns-PLA后获得的W-CNP在心肌细胞中同时显示蓝色和绿色荧光，因此，可以将其用作生物成像应用中的荧光探针。