北京生物醫(yī)學(xué)工程

數(shù)字PCR中微滴生成尺寸與頻率的數(shù)值模擬

Numerical simulation of the size and frequency ofmicro-droplets in digital PCR

作者：張森馮繼宏張弘高辛未

單位：北京工業(yè)大學(xué)生命科學(xué)與生物工程學(xué)院(北京100124)

關(guān)鍵詞：數(shù)字PCR；微流體；兩相流；微液滴；流動(dòng)聚焦

分類(lèi)號(hào)：R318.04

出版年·卷·期（頁(yè)碼）：2017·36·4（361-365）

摘要：

目的微滴合成是數(shù)字PCR中的關(guān)鍵技術(shù)，但其中兩相流速與生成微滴大小和頻率的關(guān)系尚不明確。本文采用VOF模型研究數(shù)字PCR系統(tǒng)中生成微滴的尺寸、頻率與兩相流速的關(guān)系。方法將氟化油作為連續(xù)相，反應(yīng)液(水)作為離散相，通過(guò)求解整體的動(dòng)量方程和各自相的體積分?jǐn)?shù)連續(xù)方程來(lái)實(shí)現(xiàn)相與相間的界面追蹤，模擬出微通道內(nèi)兩相的流動(dòng)情況，對(duì)不同兩相流速下微通道內(nèi)微滴生成的尺寸和頻率進(jìn)行研究。結(jié)果在不同的流速條件下，微通道內(nèi)會(huì)出現(xiàn)彈狀流、滴狀流和管狀流3種流型。并且，對(duì)于彈狀流和滴狀流，隨著連續(xù)相流速的增加，微液滴的生成尺寸減小，生成頻率增加；而隨著離散相流速的增加，微液滴的生成尺寸和頻率都會(huì)增加。結(jié)論在滴狀流狀態(tài)下，當(dāng)連續(xù)相流速為0.048~0.064m/s，并且離散相流速為0.016~0.032m/s時(shí)，可高效生成數(shù)字PCR微滴。

Objective Micro-droplets formation is one of key technologies in the digital PCR.However,the relationship between the two-phase flow rate and the size and frequency of produced micro-droplets is undeveloped.In this paper,we simulate this relationship with the volume of fluid (VOF) model in the digital PCR system.Methods We used fluorinated oil as the continuous phase and reactants (water) as the disperse phase.Through solving the momentum equation of the whole system and volume fraction equation,we monitored the profiles of produced droplets and simulated the two-phase flow in the crossing micro-channel.We mainly focused on the size and frequency of the produced droplets.Results Under different two-phase flow rates,there were three typical flow patterns:bubbly,slug and annular flow.Moreover,with the increasing of the continuous flow rate of slug flow and bubbly flow,the droplet size decreased and the frequency increased.And as the dispersed flow rate rising up,the size and the frequency of the produced micro-droplets increased accordingly.Conclusions Under slug flow,we can effectively produce micro-droplets for digital PCR when the continuous flow rate is at 0.048m/s to 0.064m/s and dispersed flow rate is at 0.016m/s to 0.032m/s,respectively.

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