Wang Jingyi, Gil-Herrera Luz Karime, Akbulut Ozge, Dumanli Ahu Gümrah
Department of Materials, The University of Manchester Oxford Road Manchester M13 9PL UK
Henry Royce Institute, The University of Manchester Oxford Road Manchester M13 9PL UK.
RSC Adv. 2025 May 15;15(21):16281-16291. doi: 10.1039/d5ra01045d.
Immobilisation of fluorescent carbon dots (C-dots) in a hydrogel matrix, such as alginates, prevents fluorescence quenching in bioimaging and biosensing applications. However, critical parameters influencing the fluorescence, including the diffusion kinetics of C-dots and their distribution within the hydrogel matrix, remain unexplored. Herein, we investigated two distinct methods for immobilising C-dots within alginate hydrogel beads: (i) adsorption and (ii) premixing the C-dots prior to hydrogel cross-linking. Our batch adsorption experiments and kinetic model fittings revealed rapid, concentration-dependent diffusion from the external solution to the beads, along with their binding to surface active sites. The rate-determining step was the diffusion into interconnecting layers within the matrix, which impacts both diffusion rates and the overall distribution of C-dots within the beads. The fluorescence signal in the hydrogel matrix from the adsorption method exhibited limited penetration depth compared to the premixed method, which showed a more uniform distribution. We demonstrated that C-dots are well-immobilised and interact effectively with the hydrogel matrix, exhibiting stable fluorescence intensities and improved structural integrity. Our findings provide valuable insights into the interaction and diffusion of C-dots in hydrogel systems and will help advance research on the fluorescence properties of C-dots for bioimaging and bio-sensing applications.
将荧光碳点（C点）固定在水凝胶基质（如藻酸盐）中，可防止其在生物成像和生物传感应用中发生荧光猝灭。然而，影响荧光的关键参数，包括C点的扩散动力学及其在水凝胶基质中的分布，仍未得到探索。在此，我们研究了两种将C点固定在藻酸盐水凝胶珠内的不同方法：（i）吸附法和（ii）在水凝胶交联之前将C点预混合。我们的批量吸附实验和动力学模型拟合表明，C点从外部溶液快速扩散到珠子中，扩散过程与浓度有关，同时它们会与表面活性位点结合。限速步骤是扩散到基质内的互连层中，这会影响扩散速率以及C点在珠子内的整体分布。与预混合法相比，吸附法在水凝胶基质中的荧光信号穿透深度有限，预混合法显示出更均匀的分布。我们证明了C点被很好地固定，并与水凝胶基质有效相互作用，表现出稳定的荧光强度和改善的结构完整性。我们的研究结果为C点在水凝胶系统中的相互作用和扩散提供了有价值的见解，并将有助于推动用于生物成像和生物传感应用的C点荧光特性的研究。
