Multifunctional Upconversion Nanocomposite for Multi-Purpose Cancer Theranostics

In this work, we introduce the upconverting detection nanoprobes UCNP-TPP-GOx based on the upconversion quenching effect recovery for the ultrasensitive, expeditious, quantitative, and in vitro cellular detection of glucose. This nanoplatform consists of upconversion nanoparticles (UCNP), tetraphenyl porphyrin (TPP) and glucose oxidase (GOx). In a nutshell, UCNPs core are linked with cancer-killing TPP via condensation reaction to form UCNP-TPP, subsequently, UCNP-TPP-GOx is fabricated through glucose oxidase (GOx) decoration on the surface of the UCNP-TPP. Additionally, UCNP-TPP-GOx possesses characteristic photophysical property and it is highly suitable for optical detection. Furthermore, UCNP-TPP-GOx shows excellent selectivity toward glucose after only 3-min coincubation and the limit of detection (LOD) for the glucose is calculated as low as 0.86 μg mL−1. Moreover, the differentiation between cancer and normal cells through in vitro confocal imaging is achieved due to the large differences of glucose level in them. More importantly, the significant inhibition on carcinoma cell growth is realized by simply switching to the specific excitation wavelength, followed by the generation of toxic singlet oxygen from TPP moiety. Hence, the developed nanoprobes presenting new possibilities for on-site rapid glucose detection and concurrent theranostics in vitro in a "one stone two birds" strategy.