奈米結構工程為一種強大且有用的技術，可以透過合成生產出具有多功能性的材料並且可應用在多方面的領域中；特別是針對具有獨特的局部表面等離子體共振的等離子體之核-殼奈米結構，它主要藉由表面增強拉曼散射（SERS）使訊號大幅地提升，使它可以偵測至分子級的超高敏感度檢測。
近期，石墨烯量子點（GQDs）是一種獨特的石墨烯衍生物，由於其優異的性能，包括低毒性，光穩定性，生物相容性和優異的溶解性，引起了很多關注。通過塗佈GQD殼可明顯地改變其光學性質和電子結構。此外，高生物相容性的金奈米粒子 (AuNPs) 結構可以在奈米結構周圍的空間狹窄區域引導有效濃度的入射光進而產生強大的電磁場，並且為SERS檢測提供強烈的共振行為。因此，GQD/AuNP核-殼奈米結構的開發可以為高靈敏度SERS檢測創造出合理設計的活性材料。然而，使用一般常規方法製備這種奈米複合物的製程通常複雜，耗時，低效率，並且需要在高溫的條件下才可以使反應進行。
在這裡，我們通過使用大氣常壓微電漿展示了GQD/AuNP複合物的快速合成方法。微電漿被定義為在電極中之幾何形狀形成的氣體放電，其尺寸至少小於1mm，使它在大氣壓下使用液態化學合成技術也可以穩定操作。另外，在微電漿中形成的高能量物質能夠引發溶液中的電化學反應和成核成奈米顆粒而無需加入額外的化學還原劑進行反應。我們可以經由詳細的顯微鏡和光譜特徵分析得知，合成的GQDs/AuNPs核-殼奈米結構的形態和尺寸分佈可以通過改變反應條件來控制。通過導入不同發光波長的GQDs或調整GQDs/AuNPs的核-殼尺寸比，可以進一步探索其奈米結構的光學性質並於SERS光譜作分析，進一步地顯示GQDs/AuNPs異質結構複合物可以作為SERS之有效基材並在生物分子傳感檢測方面具有一定相當潛力之應用價值。

Nanostructure engineering has been proposed as a powerful and useful technology to fabricate functional materials for varying applications. In particular, plasmonic core-shell nanostructures with unique localized surface plasmon resonance, allowing surface-enhanced Raman scattering (SERS) occurred for an ultra-sensitive molecular-level detection.

Recently, graphene quantum dot (GQDs), a unique type of graphene derivatives, has stimulated a lot of attentions due to their exceptional properties including low toxicity, photostability, biocompatibility and excellent solubility. By coating a GQDs shell can significantly modify the optical properties and electronic structure. Moreover, bio-compatible Au nanostructures can generate great electromagnetic fields, leading a effective concentration of the incident light at the spatially narrow region around the nanostructures, providing a strong resonant behavior for SERS detection. Hence, the development of GQD/AuNP core-shell nanostructures can create a rational design of active materials for high sensitive SERS detection. However, the conventional approaches to prepare such nanohybrids are usually complicated, time consuming, inefficiency, and high temperature required.

Here we demonstrate a rapid synthesis method of GQD/AuNP by using atmospheric-pressure microplasmas. Microplasmas are defined as gaseous discharges formed in electrode geometries where at least one dimension is less than 1mm, which can be operated stably with an aqueous solution at atmospheric pressure. Energetic species formed in the microplasma are capable to initiating electrochemical reactions and nucleating particles in solution without chemical reducing agents. Detailed microscopic and spectroscopic characterizations indicate that the morphology and size distribution of as-produced GQDs/AuNPs core-shell nanostructures can be controlled via changing the reaction conditions. By sourcing different emissions of GQDs or adjusting core to shell ratio of GQDs/AuNPs nanostructure can further explore their optical properties for the SERS spectroscopic analysis and suggest that GQDs/AuNPs heterostructures can performed as an effective material for SERS-based biomolecular sensing.

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