1、LOGOMultiple and High-Throughput Droplet Reactions via Combination of Microsampling Technique and Microfluidic ChipMembers:李娜 冯双霞 徐秋燕 刘婷婷 聂怀军ContentsBackground ExperimentABSTRACTDiscussionABSTRACTMicrodroplets offer unique compartments for accommodating a large number of chemical and biological reac
2、tions in tiny volume with precise control.A major concern in droplet-based microfluidics is the difficulty to address droplets individually and achieve high throughput at the same time.Here,we have combined an improved cartridge sampling technique with a microfluidic chip to perform droplet screenin
3、gs and aggressive reaction with reagent consumption.Our combined device provides a simple model to utilize multiple droplets for various reactions with low reagent consumption and high throughput.BackgroundA large number of reactions can be independently miniaturized into tiny droplets ranging from
4、nanoliter to picoliter sizes without having to increase the chip size and complexity.Microfluidic chips have provided a powerful platform for accomplishing droplet formation and manipulation within one chip of only a few square centimeters in size.AdvantagesOver the past few years,droplet-based micr
5、ofluidics has attracted increasing attention.BackgroundBackground Droplet generation for multiple samplesDroplet generation for multiple samples is limited by the“world-to-chip”is limited by the“world-to-chip”interface problem and cannot be interface problem and cannot be addressed individually addr
6、essed individually Droplet generation and manipulationDroplet generation and manipulation functions within one chip can easily functions within one chip can easily interfere with each other and are difficult interfere with each other and are difficult To balance,despite being separated To balance,de
7、spite being separated by a long,winding channel.by a long,winding channel.Drawback Passive droplet formation methods:InnovatevThis context shows a hybrid device:This context shows a hybrid device:the the cartridge droplet generation technique cartridge droplet generation technique combined with a mi
8、crofluidic bined with a microfluidic chip.vThey improved the cartridge technique They improved the cartridge technique with a novel movement scheme:the with a novel movement scheme:the capillary,instead of the multiwell plate,was capillary,instead of the multiwell plate,was moved by a digital and au
9、tomatic moved by a digital and automatic manipulator to aspirate different samples manipulator to aspirate different samples or the covering oilor the covering oil.vThe hybrid droplet device for generation and manipulation consists of four major components.v(a)manipulatorv(b)multiwell platev(c)capil
10、laryv(d)PDMS chipThree general steps load the multiwell plate with different samples,cover with a layer of oil,and input theparameters of the desired droplet array into the controller via a PC start the controller to aspirate certain volumes of samples and oil into the Capillary sequentially introdu
11、ce the generated droplets into the PDMS chip for merging,mixing,detection,or other manipulation.Laboratory reagent v silicone oil,FeCl24H2O(SigmaAldrich),FeCl36H2O(Acros Organics),ammonium hydroxide solution(28%NH3 Fluka),and hydrochloric acid(37%HCl,Acros Organics)Improved Sampling Technique Combin
12、ed Droplet Device Performance High-Throughput Droplet Screening Aggressive Droplet Reaction Improved Sampling TechniqueThe capillary aspirates the oil when the cantilever remains in the“up”state.When the cantilever is triggered to stay in the“down”state,the capillary aspirates the sample.The residen
13、ce time in the oil(TO)and sample(TS)could be adjusted respectively to generate droplets with desired distance and volume.(c)Relative intensity was measured along the channel starting from top right corner.The intensity of fluorescein and DI water droplet does not decrease or increase,which indicates
14、 that no cross-contamination between these two samples was detected.(b)Droplet array was generated by sequentially aspirating 50 uM fluorescein and DI water.Combined Droplet Device PerformanceHere,the merging of droplets was demonstrated in a PDMS chip.The droplets fusion does not depend on droplet
15、distance but droplet velocity and Vd/Vc.After mixing completely,the merged droplet was output to a sinuous channel for display and detection.In the first application,a series of Ai and Bm,n(i=1 2,m=1 3,and n=1 6)were generated.A1and A 2 are Fluo-4 and Rhod-2 solutions with the same concentration(10.
16、8 M),which are indicators that exhibit an increase in fluorescence(green/red)upon metal ion bonding.A value of m=1 3 represent metalsion solutions of LaIII,Yb III,and YIII,respectively,while n=1 6 are six different metal ion concentrations(0,2.5,5,10,20,and40 M)of these solutions.The droplet array c
17、ontains 72 1-nLdropletsHigh-Throughput Droplet ScreeningThe 36 pairs of droplet reactions used 72 nL of solutionand required 1.8 min to complete.Therefore,the reagentconsumption for each measurement could be reduced to 1 nL per sample,and the reaction throughput is 1200 is 1200 h1,h1,which can be mu
18、ch faster much faster by increasing the flow velocity.The screening droplets could be stored in the PDMS chip after we stopped the vacuum.Aggressive Droplet Reaction From these images,we found that the coprecipitation is so fast that it immediately forms particles when two droplets come into contact
19、 with each other.Moreover,in each volume ratio,the precipitation initiated bythe fusion of two droplets did not block the microchannel at such high concentrations.Such flexible,controllable and miniaturized reaction conditions are extremely suitable for aggressive,fast,or even explosive reactions th
20、at generate precipitation or heat.Discussionv The cartridge droplet generation method provides an efficient way for introducing different nanoliter droplets into the microfluidic chip.v the microfluidic chip offers a platform for delicate manipulation such as merging.This feature is valuable for red
21、ucing the reaction screening and optimization cost and time and is particularly useful for drug screening.Compared with the other cartridge droplet generation,our design used a digital and automatic manipulator to move the capillary instead of the multiwell plate.DiscussionSubsequently,the covering
22、oil was ingeniously used as a carrier fluid(continuous-phase)to avoid evaporation and cross-contamination.The droplet generation throughputs in our sampling device increased to 1 5 s per droplet,which is efficient and versatile for arbitrary,multiple,and high-throughput droplet generation and could
23、be increased by increasing the flow velocity.This improved cartridge technique and microfluidic chip were integrated to make use of their respective advantages for performing response calibrations and aggressive reaction and screening multiple reaction conditions with minimal(nL)reagent consumption.LOGO2019.11.19docin/sanshengshiyuandoc88/sanshenglu 更多精品资源请访问更多精品资源请访问
