BSA-capped gold nanoclusters are promising theragnostic systems that can be excited to render both fluorescence emission and reactive oxygen species. Although their synthesis and photoluminescence properties are already well described, more accurate information about their use as photosensitizers is required in order to advance towards health applications. In this work, we have obtained BSA-capped gold nanoclusters and characterized their photophysics by different techniques. Singlet oxygen production was detected upon irradiation, which was enough to produce toxicity on two cell lines. Remarkably, an internal energy transfer, probably due to the presence of smaller nanoclusters and the contribution of oxidized residues of BSA in the system, caused fluorescence emission near 640 nm after excitation in the UV range. Additionally, the system was capable of penetrating human skin beyond the stratum corneum, which enhances the potential of these nanoclusters as bifunctional photodynamic therapy effectors and biomarkers with application in a diversity of skin diseases. In the absence of radiation, BSA-capped gold nanoclusters did not cause toxicity in vitro, while their toxic effect on an in vivo model as zebrafish was determined.

BSA封端的金纳米簇是很有前途的睫毛膏系统，可以被激发以产生荧光发射和活性氧。尽管已经很好地描述了它们的合成和光致发光特性，但是需要更准确的信息来将其用作光敏剂，才能迈向健康应用。在这项工作中，我们获得了BSA封端的金纳米团簇，并通过不同技术对其光物理特性进行了表征。辐射后检测到单线态氧的产生，足以在两个细胞系上产生毒性。值得注意的是，内部能量转移可能是由于较小的纳米团簇的存在和系统中BSA氧化残基的作用所致，在紫外线范围内激发后，在640 nm附近发出了荧光。另外，该系统能够穿透角质层以外的人类皮肤，从而增强了这些纳米簇作为双功能光动力疗法效应物和生物标记物的潜力，并应用于多种皮肤疾病。在没有辐射的情况下，BSA封端的金纳米团簇不会引起毒性在体外，同时确定了它们对斑马鱼等体内模型的毒性作用。