聚合酶連鎖反應(PCR)是一種擴增特定 DNA 片段從而檢測和定量特定基因存在的方法，並且自從發明以來便被大量運用在生物醫學領域中。傳統PCR中的熱循環過程主要依靠熱電冷卻器來加熱/冷卻試管內的樣品。然而此方式需要通過許多熱阻達到加熱樣品的目的，因此大幅降低了電功效率以及需要較長的反應時間。近年來提出了一種新穎的PCR加熱機制: 藉由在PCR試劑中加入具光熱轉換性質的奈米材料例如金以及氧化鐵奈米粒子，並藉由光激發來實現內部加熱。此方式除了加速反應時間外也能有效的節省機器的大小。然而金奈米粒子的熱穩定性備受考量以及氧化鐵奈米粒子的製備複雜性使兩者在其進一步應用中受到限制。在此，我們開發了具多巴胺奈米粒子(PDA NPs)作為光分子PCR加熱試劑的替代成分。PDA NPs的磷苯二酚基團使其螯合PCR反應緩衝液中的鎂等多價金屬離子藉此影響反應過程。此外因螯合誘導的DNA吸附在經過PCR後更嚴重的引發聚集。為了克服這些問題，我們發現加入牛血清白蛋白(BSA)能夠在奈米材料外形成蛋白質電暈並阻止金屬螯合以及DNA吸附。此研究不僅提出PDA NPs如何與光分子PCR中的成份相互作用提供了詳細的機制討論，同時做為第一個有機奈米材料應用於光分子PCR啟發了未來其他有機材料的光分子PCR的應用。

Polymerase chain reaction aimed to amplify specific DNA fragments for specific genes’ quantitative detection. Traditional PCR mostly rely on thermoelectric heating/cooling mechanism from outside PCR tubes which compromises power and time efficiency. A novel direct photothermal modulation has revolutionized PCR in accelerating sample-to-data process by “internal heating” using nanomaterials such as Au and Fe3O4 particles. However, the stability and preparation complexity render significant limitations in further applications. Here, we developed a one-pot synthesis of polydopamine (PDA) photothermal nanoparticles for next generation photonic PCR. PDA has multivalent metal ion ligand in catechol group that chelates Mg2+ in PCR reaction buffers thus inhibit the reaction. Further, PDA could absorb DNA and induced serious aggregation in PCR cycles. We discovered that bovine serum albumin (BSA) was able to form protein corona and effectively blocked metal chelation as well as DNA absorption and perform efficient photonic PCR. Detail mechanism was explored including the interaction of PDA with PCR reagent and lasing. This study enlightened the use of organic nanomaterials in accelerated photonic PCR for point-of-care quantitative diagnostics.

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