Upconversion metal oxide aerogels for diagnostics and sorption of toxicants

IntroductionThe drugs, which are applied in modern methods of cancer and thrombosis treatment, are often lead to fatal outcome of patients because of toxic effect of these. Consequently, the development of materials for both... [ view full abstract ]

Introduction

The drugs, which are applied in modern methods of cancer and thrombosis treatment, are often lead to fatal outcome of patients because of toxic effect of these. Consequently, the development of materials for both diagnostics (imaging, biodetection) and sorption of toxicants from blood is highly actual challenge of today. Aerogels are interesting matrix for such an application, because their surface area is giant, which is suitable for the role of adsorbent. Next, it was decided to produce aerogels with upconversion luminescence in order to provide diagnostic property based on ability to transform, for instance, NIR radiation to visible and UV regions via a nonlinear optical process. ZrO₂, HfO₂ and Ta₂O₅ (preliminary doped by Er³⁺ and Yb³⁺ ions for upconversion effect) were chosen as substrates thanks to their biocompatibility and ability to form stable gels.

Methods

ZrO₂, HfO₂ and Ta₂O₅ aerogels were obtained by controlled hydrolysis and polycondensation of corresponding precursors, followed by drying on supercritical CO₂ extractor. Materials were characterized by HR TEM, XRD, FTIR, N₂ sorption and AFM methods. The optical and upconversion properties of aerogels monoliths were studied, doxorubicinum sorption was measured.

Results and Discussion

Stable metal oxide aerogels doped by Er³⁺ and Yb³⁺ ions where produced. The samples demonstrated upconversion luminescence due to the fact, that rare-earth ions built in crystalline structure of matrices. The materials have also shown high surface area, which resulted in good sorption of doxorubicinum in the corresponding experiment. Overall, it was proved, that upconversion aerogels are perspective candidate for bioimaging, biodetection and adsorption both in vitro and in vivo.