Micropatterning of Quantum Dots for Biofunctionalization and Nanoimaging

Micron-scale patterning of colloidal quantum dots (QDs) is extremely important for the fabrication of high-performance Quantum dot Light-Emitting Diode (QLED) displays, biosensing, and super-resolution imaging. Thus, several nondestructive methods have been recently proposed, such as spatial self-organization. However, none of them can be useful for biofunctionalization or nanoimaging. To address this limitation, we propose a method to create micropatterns of QDs of any shape and size. UV photolithography assisted by a digital micromirror device (DMD) and silanization allow creating an adhesive layer, on which QDs micropatterns can be assembled with a 2 mu m resolution. The patterns are composed of a monolayer of CdSe/CdS/CdZnS/ZnS core/multishell QDs (7 +/- 1 nm in diameter, emitting at 590 nm) with a high surface density (typically 4000 QDs/mu m2). We also demonstrate that it is possible to reversibly bind any kind of His Tagged proteins on the QDs surface. This is highlighted by measuring FRET (Fo''rster Resonance Energy Transfer) with a dedicated polymer exhibiting on one end Alexa Fluor 647 (AF647) and on the other end eight imidazole cycles, allowing chelation on the quantum dots' surface. Therefore, this patterning protocol provides a path to combine nanoimaging with cell patterning through a relevant biofunctionalization.

Automated summary

Micron-scale patterning of colloidal quantum dots is crucial for various applications. A new method is proposed to create micropatterns of QDs with high resolution using UV photolithography and silanization. The ability to bind proteins on the QDs surface opens up possibilities for biofunctionalization and nanoimaging.