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Synthesis and Surface Modification of Porous Silicon Quantum Dots with Enhanced Photoluminescence for Bioimaging Applications

CSEF · 2023 Chemistry Fourth Award

Zhang Jocelyn · 11

Overview

Around 50% of cancers are only diagnosed at late stages, due to a lack of early cancer detection techniques. Quantum dots (QDs) have emerged as a new class of fluorescent labels for ultra high sensitivity bioimaging, as an important tool for early cancer detection. However, most quantum dots and current fluorescent material have high metal content with toxicity concerns, and photoluminescence (PL) intermittency issues, they tend to blink off during operation, which still causes inaccuracies. The objective of this study is to synthesize and modify the porous silicon quantum dots(PSiQDs) to suppress the QDs PL blink off issue and establish QDs PL recovery capability, to provide the prolonged QDs’ PL life, which can significantly improve the bioimaging accuracy by differentiating from tissue autofluorescence. In this study, the porous silicon nanostructure with photoluminescence was first achieved through the electrochemical etching process experiments. The second phase experiment was conducted to form Si-SiO2 core shell structure, to improve QDs PL stability and increase PL lifespan. In the third phase, a test setup is established to reliably emulate and measure the QDs blink effect, then the photoluminescence recovery experiments are conducted and compared through different thermal heating processes. The last phase is to apply the enhanced porous silicon quantum dots with prolonged PL lifespan to improve bioimaging accuracy, with time gated study. The results show that a significant improvement in photoluminescence stability has been achieved through the porous silicon nanostructure and Si-SiO2 core-shell structure formed. The modified PSiQDs’ PL blink off issue is greatly suppressed, compared with non-coated QDs. The elevated temperatures consistently recovered the QDs PL after blink off, which further extended the quantum dots’ stability. This is also the first study on QDs blink off recovery through a thermal heating process. The study will be beneficial for cancer early detection and high sensitive bioimaging application, by providing an enhanced silicon quantum dots with high accuracy, a prolonged PL life and stability, as a biodegradable and non-toxic fluorescent material.

Source coverage

This record comes from a published award list, not a complete project archive. Its abstract comes from CSEF's public project showcase as archived by the Internet Archive before judging (https://web.archive.org/web/20230401224130/https://ca-csef.zfairs.com/showcase/ShowcaseInfo?f=838e60b7-ea75-46e8-865c-fde4864244b3); the version presented may differ.

Awards (1)

Competition history

  • CSEF 2023 Chemistry · Entry S0615

Resources

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