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Beelee Chua received B.Eng (Hon). and M.Eng. degrees in mechanical engineering from the National University of Singapore in 1999 and 2001 respectively, and Ph.D. degree in electrical engineering from UC Davis in 2005. He was also a member of Berkeley Sensor and Actuator Center (BSAC). From 2006 to 2012, he was with a biomedical device startup company in the San Francisco Bay Area. He is currently an Associate Professor in the School of Electrical Engineering, Korea University, Korea. His research interest revolves around small reactive responsive systems. They currently include high voltage micro devices, micro corona ionizers and applications, wearable diagnostics and therapeutics as well as environmental monitoring systems and devices.
The iconic pipette was integrated with an electrochemical pH sensor for preventing cross-contamination while still enabling pH measurements in industrial fermentation reactors. Contamination is a big financial cost source of the fermentation industry and periodic parameter (such as pH, dissolved oxygen, temperature, etc.) measurements are crucial for a successful fermentation run. Yet, the very act of measuring poses contamination risks to the fermentation reactors. To resolve the dichotomy between the need for pH monitoring and cross-contamination prevention, we developed a pH sensing pipette (composed of an integrated electrochemical polyaniline-based pH sensitive electrode, flowcell, and readout circuit) with a disposable pipette tip for cross-contamination-free pH measurements. This pH sensing pipette achieved a system-level sensitivity of 134.8 mV/pH, a limit of detection of pH 0.029 103, and an average response time of 2.6 - 6.0 s, which is good enough for pH measurements in industrial fermentation reactors. It was then demonstrated to monitor the pH of ethanol fermentation across two days successfully, implying that this device may be used to further prevent cross-contamination risks in industrial fermentation processes.
Saeyoung Kim; Ji-Hoon Han; Beelee Chua; James Jungho Pak. A pH sensing pipette for cross-contamination prevention in industrial fermentation. IEEE Transactions on Industrial Electronics 2021, PP, 1 -1.
AMA StyleSaeyoung Kim, Ji-Hoon Han, Beelee Chua, James Jungho Pak. A pH sensing pipette for cross-contamination prevention in industrial fermentation. IEEE Transactions on Industrial Electronics. 2021; PP (99):1-1.
Chicago/Turabian StyleSaeyoung Kim; Ji-Hoon Han; Beelee Chua; James Jungho Pak. 2021. "A pH sensing pipette for cross-contamination prevention in industrial fermentation." IEEE Transactions on Industrial Electronics PP, no. 99: 1-1.
Principle of an ssDNA paired aptasensor where extra dye binding sites are created to enhance its fluorescence response.
Seo Won Cho; Hyun Jeong Lim; Beelee Chua; Ahjeong Son. Single-stranded DNA probe paired aptasensor with extra dye binding sites to enhance its fluorescence response in the presence of a target compound. RSC Advances 2021, 11, 21796 -21804.
AMA StyleSeo Won Cho, Hyun Jeong Lim, Beelee Chua, Ahjeong Son. Single-stranded DNA probe paired aptasensor with extra dye binding sites to enhance its fluorescence response in the presence of a target compound. RSC Advances. 2021; 11 (35):21796-21804.
Chicago/Turabian StyleSeo Won Cho; Hyun Jeong Lim; Beelee Chua; Ahjeong Son. 2021. "Single-stranded DNA probe paired aptasensor with extra dye binding sites to enhance its fluorescence response in the presence of a target compound." RSC Advances 11, no. 35: 21796-21804.
Chia seeds were used to significantly improve the separation efficiency of polyvinyl chloride (PVC) microplastics from water samples via centrifugation. Upon hydration, the mucilage of chia seeds were able to capture PVC microplastics with sizes ranging from tens to hundreds of micrometers. Since PVC microplastics contained di-2-etylhexyl phthalate (DEHP) as a plasticizer (verified via Fourier transform infrared spectrometry), DEHP was used as an indicator in the subsequent quantification via gas chromatography – mass spectrometry (GC-MS) analysis. Specifically after verifying the DEHP peak in the GC spectrum using DEHP reference standard as a positive control, the GC spectral area of that peak was used to quantify the amount of DEHP in the sample. Using nominal operation settings at 10 min and 1000 rpm with 100 mg of chia seeds, the separation efficiency could be improved by 5 times (500%) as compared to the absence of chia seeds. Furthermore, chia seeds were also compatible with simulated synthetic wastewater samples. Most importantly, the use of chia seeds did not interfere with GC-MS quantification protocol and accuracy. The result suggested the proposed method can be used as a simple screening tool of microplastics entering wastewater treatment plant, even though a series of follow-up studies are needed in future.
Doyeon Park; Dabin Kim; Hyun Jeong Lim; Chanhyuk Park; Beelee Chua; Jae Woo Lee; Yeomin Yoon; Ahjeong Son. Chia seed-assisted separation and detection of polyvinyl chloride microplastics in water via gas chromatography mass spectrometry. Chemosphere 2021, 273, 129599 .
AMA StyleDoyeon Park, Dabin Kim, Hyun Jeong Lim, Chanhyuk Park, Beelee Chua, Jae Woo Lee, Yeomin Yoon, Ahjeong Son. Chia seed-assisted separation and detection of polyvinyl chloride microplastics in water via gas chromatography mass spectrometry. Chemosphere. 2021; 273 ():129599.
Chicago/Turabian StyleDoyeon Park; Dabin Kim; Hyun Jeong Lim; Chanhyuk Park; Beelee Chua; Jae Woo Lee; Yeomin Yoon; Ahjeong Son. 2021. "Chia seed-assisted separation and detection of polyvinyl chloride microplastics in water via gas chromatography mass spectrometry." Chemosphere 273, no. : 129599.
Principle of ozonation enhanced dsDNA binding dye based fluorescence measurement of total bacterial load in water.
Jiwon Choi; Beelee Chua; Ahjeong Son. Ozonation enhancement of low cost double-stranded DNA binding dye based fluorescence measurement of total bacterial load in water. RSC Advances 2021, 11, 3931 -3941.
AMA StyleJiwon Choi, Beelee Chua, Ahjeong Son. Ozonation enhancement of low cost double-stranded DNA binding dye based fluorescence measurement of total bacterial load in water. RSC Advances. 2021; 11 (7):3931-3941.
Chicago/Turabian StyleJiwon Choi; Beelee Chua; Ahjeong Son. 2021. "Ozonation enhancement of low cost double-stranded DNA binding dye based fluorescence measurement of total bacterial load in water." RSC Advances 11, no. 7: 3931-3941.
Electrical discharge treatment was shown to be a viable substitution for chelating agent in genomic assays.
Hyowon Jin; Yeomin Yoon; Mark R. Liles; Beelee Chua; Ahjeong Son. A simple reagent-less approach using electrical discharge as a substitution for chelating agent in addressing genomic assay inhibition by divalent cations. The Analyst 2020, 145, 6846 -6858.
AMA StyleHyowon Jin, Yeomin Yoon, Mark R. Liles, Beelee Chua, Ahjeong Son. A simple reagent-less approach using electrical discharge as a substitution for chelating agent in addressing genomic assay inhibition by divalent cations. The Analyst. 2020; 145 (21):6846-6858.
Chicago/Turabian StyleHyowon Jin; Yeomin Yoon; Mark R. Liles; Beelee Chua; Ahjeong Son. 2020. "A simple reagent-less approach using electrical discharge as a substitution for chelating agent in addressing genomic assay inhibition by divalent cations." The Analyst 145, no. 21: 6846-6858.
In this paper, we developed a non-equilibrium rapid replacement aptamer (NERRA) assay that performed ultra-fast (in 30 s) quantitative detection of phthalic acid esters (PAEs) without waiting for the reaction to reach equilibrium. NERRA assay employed fluorescence PoPo3 dye intercalated in an ssDNA aptamer to selectively detect and quantify the PAEs in water. As the intercalated dye was replaced by the PAEs and quenched in the water, the rate of fluorescence change became proportional to PAEs concentration. The sensitivity of NERRA assay was first evaluated with a commercial spectrofluorometer. The selectivity for PAE mixture, individual PAEs, and non-phthalate compounds were also investigated. NERRA assay was also able to quantitatively detect the PAEs in a common plastic product (picnic mat), and the results were compared with those of gas chromatography mass spectrometry. Finally, a custom analyzer (8.5 cm × 8.5 cm × 16.5 cm) was built to demonstrate the portability of the NERRA assay. Using a commercial spectrofluorometer, NERRA assay was able to quantitatively detect a PAE mixture in 30 min with an LOQ of 0.1 μg/L. Using the portable custom analyzer, the detection time was shortened to 30 s with a tradeoff in the LOQ (1 μg/L). In both cases, the LOQs remain within the environmentally relevant PAE concentrations of 0.1–1472 μg/L.
Dabin Kim; Hyun Jeong Lim; Yun Gyong Ahn; Beelee Chua; Ahjeong Son. Development of non-equilibrium rapid replacement aptamer assay for ultra-fast detection of phthalic acid esters. Talanta 2020, 219, 121216 .
AMA StyleDabin Kim, Hyun Jeong Lim, Yun Gyong Ahn, Beelee Chua, Ahjeong Son. Development of non-equilibrium rapid replacement aptamer assay for ultra-fast detection of phthalic acid esters. Talanta. 2020; 219 ():121216.
Chicago/Turabian StyleDabin Kim; Hyun Jeong Lim; Yun Gyong Ahn; Beelee Chua; Ahjeong Son. 2020. "Development of non-equilibrium rapid replacement aptamer assay for ultra-fast detection of phthalic acid esters." Talanta 219, no. : 121216.
Biodegradable superabsorbent polymer is used as a battery substitute in a self-powered insulin patch pump. It highlights the possibility of addressing used batteries in medical waste stream and its environmental contamination without compromising on healthcare standards.
Jiaying Shao; King Ho Holden Li; Ahjeong Son; Beelee Chua. A self-powered insulin patch pump with a superabsorbent polymer as a biodegradable battery substitute. Journal of Materials Chemistry B 2020, 8, 4210 -4220.
AMA StyleJiaying Shao, King Ho Holden Li, Ahjeong Son, Beelee Chua. A self-powered insulin patch pump with a superabsorbent polymer as a biodegradable battery substitute. Journal of Materials Chemistry B. 2020; 8 (19):4210-4220.
Chicago/Turabian StyleJiaying Shao; King Ho Holden Li; Ahjeong Son; Beelee Chua. 2020. "A self-powered insulin patch pump with a superabsorbent polymer as a biodegradable battery substitute." Journal of Materials Chemistry B 8, no. 19: 4210-4220.
We have demonstrated the feasibility of a gummy bear-based gnathodynamometer for masticatory diagnostics. Using a gummy bear as a force transducer and bamboo cantilevers as mechanical springs, the masticatory force of a human mandible can be measured via electrical impedance measurement (presented as the output voltage of the gnathodynamometer). The frequency response of the gummy bear is experimentally tested from 0.1 to 100 kHz and shown to be consistent with the analytical model. For a given driving frequency, the output voltage of the gnathodynamometer is experimentally measured for a range of stimulated masticatory forces (˜3.49 to 88.50 N). The masticatory force limit is also adjustable via the driving frequency (10 to 100 kHz) and cantilever length (via sliding datum, L = 95, 75, and 50 mm). This also adjusts the masticatory force sensitivity in the range of ˜17.5 to 40.5 mV/N. The clinical feasibility is also evaluated using three human subjects. The combination of candy (gummy bear) and diagnostics heralds a new class of low-cost medical devices that generate minimum recalcitrant medical waste and that are suitable for developing countries.
Donghyun Lee; Beelee Chua. Gummy bear-based gnathodynamometer for masticatory diagnostics. Sensors and Actuators A: Physical 2019, 290, 80 -89.
AMA StyleDonghyun Lee, Beelee Chua. Gummy bear-based gnathodynamometer for masticatory diagnostics. Sensors and Actuators A: Physical. 2019; 290 ():80-89.
Chicago/Turabian StyleDonghyun Lee; Beelee Chua. 2019. "Gummy bear-based gnathodynamometer for masticatory diagnostics." Sensors and Actuators A: Physical 290, no. : 80-89.
We have developed a quantum dot aptasensor (QD-aptasensor) and its accompanying portable analyzer for the detection of di-2-ethylhexyl phthalate (DEHP). This sensor is based on a newly screened aptamer (60-mer) via SELEX and shows a binding affinity of 213 nmol/L with DEHP. The 60-mer aptamer together with its three shorter truncated aptamers (45, 28, and 22-mer) as well as three different DNA probes (12, 9, and 13-mer) were further investigated to form the best combination for the QD-aptasensor. Using a 22-mer-truncated aptamer and a 12-mer DNA probe combination, the QD-aptasensor demonstrated excellent DEHP sensitivity with an LOQ = 0.5 pg/mL as well as good selectivity in the presence of other phthalate analogs. The binding between the truncated aptamers and DEHP was also characterized. Finally, a QD-aptasensor-based portable analyzer was also developed, and its equivalence to the laboratory protocol was established with a correlation coefficient r = 0.86 for DEHP concentrations ranging from 0.0005 to 100 ng/mL.
Hyun Jeong Lim; A-Ru Kim; Moon-Young Yoon; Youngmin You; Beelee Chua; Ahjeong Son. Development of quantum dot aptasensor and its portable analyzer for the detection of di-2-ethylhexyl phthalate. Biosensors and Bioelectronics 2018, 121, 1 -9.
AMA StyleHyun Jeong Lim, A-Ru Kim, Moon-Young Yoon, Youngmin You, Beelee Chua, Ahjeong Son. Development of quantum dot aptasensor and its portable analyzer for the detection of di-2-ethylhexyl phthalate. Biosensors and Bioelectronics. 2018; 121 ():1-9.
Chicago/Turabian StyleHyun Jeong Lim; A-Ru Kim; Moon-Young Yoon; Youngmin You; Beelee Chua; Ahjeong Son. 2018. "Development of quantum dot aptasensor and its portable analyzer for the detection of di-2-ethylhexyl phthalate." Biosensors and Bioelectronics 121, no. : 1-9.
In this paper, we have demonstrated the feasibility of using microorganism-ionizing respirators with reduced breathing resistance to remove airborne bacteria. Using a miniaturized corona ionizer and two pairs of separator electrodes, airborne bacteria were ionized and removed from the airflow. Two microorganism-ionizing respirator designs were experimentally evaluated with flow rates ranging from ∼10 to 20 L/min and yielded airborne bacterial removal efficiencies of ∼75%–100%. Further, they were in close agreement with the analytical airborne particle removal efficiencies, at a similar range of flow rates. These flow rates also correspond to the breathing rates of standing and walking adults. More importantly, the breathing resistance could be reduced by more than 50% for flow rates of ∼200 L/min. Using manganese (IV) oxide coated mesh, the ozone concentration in the air outflow was reduced to less than 0.1 ppm, at a flow rate of ∼20 L/min, thus enabling safe use. The power consumption was less than 1 W.
Miri Park; Ahjeong Son; Beelee Chua. Microorganism-ionizing respirator with reduced breathing resistance suitable for removing airborne bacteria. Sensors and Actuators B: Chemical 2018, 276, 437 -446.
AMA StyleMiri Park, Ahjeong Son, Beelee Chua. Microorganism-ionizing respirator with reduced breathing resistance suitable for removing airborne bacteria. Sensors and Actuators B: Chemical. 2018; 276 ():437-446.
Chicago/Turabian StyleMiri Park; Ahjeong Son; Beelee Chua. 2018. "Microorganism-ionizing respirator with reduced breathing resistance suitable for removing airborne bacteria." Sensors and Actuators B: Chemical 276, no. : 437-446.
DNA hybridization-based assays are well known for their ability to detect and quantify specific bacteria. Assays that employ DNA hybridization include a NanoGene assay, fluorescence in situ hybridization, and microarrays. Involved in DNA hybridization, fragmentation of genomic DNA (gDNA) is necessary to increase the accessibility of the probe DNA to the target gDNA. However, there has been no thorough and systematic characterization of different fragmented gDNA sizes and their effects on hybridization efficiency. An optimum fragmented size range of gDNA for the NanoGene assay is hypothesized in this study. Bacterial gDNA is fragmented via sonication into different size ranges prior to the NanoGene assay. The optimum size range of gDNA is determined via the comparison of respective hybridization efficiencies (in the form of quantification capabilities). Different incubation durations are also investigated. Finally, the quantification capability of the fragmented (at optimum size range) and unfragmented gDNA is compared.
Xiaofang Wang; Beelee Chua; Ahjeong Son. The Implications of Fragmented Genomic DNA Size Range on the Hybridization Efficiency in NanoGene Assay. Sensors 2018, 18, 2646 .
AMA StyleXiaofang Wang, Beelee Chua, Ahjeong Son. The Implications of Fragmented Genomic DNA Size Range on the Hybridization Efficiency in NanoGene Assay. Sensors. 2018; 18 (8):2646.
Chicago/Turabian StyleXiaofang Wang; Beelee Chua; Ahjeong Son. 2018. "The Implications of Fragmented Genomic DNA Size Range on the Hybridization Efficiency in NanoGene Assay." Sensors 18, no. 8: 2646.
The NanoGene assay is an inhibitor-resistant gene quantification assay based on magnetic bead and quantum dot nanoparticles. It employs a set of probe and signaling probe DNAs to capture target DNA via hybridization. Using simple DNA preparation that bypasses conventional DNA extraction, it was able to detect and quantify specific bacterial genes in environmental sample. In this study, the vulnerability of the NanoGene assay to the presence of various environmental factors was investigated. A total of 43 soil samples were inoculated with 109 CFU/mL of Pseudomonas putida prior to DNA isolation without purification. Subsequently, the NanoGene assay was performed for quantitative detection of P. putida with respect to 12 soil properties including pH, moisture, humic acids, organic matter, sand, silt, clay, cation exchange capability, sodium, potassium, magnesium, and calcium. Using multiple linear regression, the NanoGene assay was found to be particularly vulnerable to the presence of Mg2+, which was selected as a major variable (P = 0.001). The vulnerability of the NanoGene assay to Mg2+ was further explored by atomic force microscopy, which indicated significant Mg2+-mediated DNA aggregation. The inhibition of the NanoGene assay from some soil samples as a consequence of DNA aggregation could therefore be prevented by the use of Mg2+ chelators such as EDTA, enabling application of this method across diverse soil types.
Xiaofang Wang; Hyojin Kweon; Seokho Lee; Hyejin Shin; Beelee Chua; Mark R. Liles; Ming-Kuo Lee; Ahjeong Son. Vulnerability of DNA hybridization in soils is due to Mg2+ ion induced DNA aggregation. Soil Biology and Biochemistry 2018, 125, 300 -308.
AMA StyleXiaofang Wang, Hyojin Kweon, Seokho Lee, Hyejin Shin, Beelee Chua, Mark R. Liles, Ming-Kuo Lee, Ahjeong Son. Vulnerability of DNA hybridization in soils is due to Mg2+ ion induced DNA aggregation. Soil Biology and Biochemistry. 2018; 125 ():300-308.
Chicago/Turabian StyleXiaofang Wang; Hyojin Kweon; Seokho Lee; Hyejin Shin; Beelee Chua; Mark R. Liles; Ming-Kuo Lee; Ahjeong Son. 2018. "Vulnerability of DNA hybridization in soils is due to Mg2+ ion induced DNA aggregation." Soil Biology and Biochemistry 125, no. : 300-308.
Sangbin Jeon; Beelee Chua. Conductive polylactic-acid filament for dose monitoring in syringe-less wearable infusion pump. Sensors and Actuators B: Chemical 2018, 258, 1080 -1089.
AMA StyleSangbin Jeon, Beelee Chua. Conductive polylactic-acid filament for dose monitoring in syringe-less wearable infusion pump. Sensors and Actuators B: Chemical. 2018; 258 ():1080-1089.
Chicago/Turabian StyleSangbin Jeon; Beelee Chua. 2018. "Conductive polylactic-acid filament for dose monitoring in syringe-less wearable infusion pump." Sensors and Actuators B: Chemical 258, no. : 1080-1089.
We have demonstrated the detection of cyanobacteria in eutrophic water samples using a portable electrocoagulator and NanoGene assay. The electrocoagulator is designed to pre-concentrate cyanobacteria from water samples prior to analysis via NanoGene assay. Using Microcystis aeruginosa laboratory culture and environmental samples (cell densities ranging from 1.7 × 105 to 4.1 × 106 and 6.5 × 103 to 6.6 × 107 cells·mL-1, respectively), the electrocoagulator was evaluated and compared with a conventional centrifuge. Varying the operation duration from 0 to 300 s with different cell densities was first investigated. Pre-concentration efficiencies (obtained via absorbance measurement) and dry cell weight of pre-concentrated cyanobacteria were then obtained and compared. For laboratory samples at cell densities from 3.2 × 105 to 4.1 × 106 cells·mL-1, the pre-concentration efficiencies of electrocoagulator appeared to be stable at ~60%. At lower cell densities (1.7 and 2.2 × 105 cells·mL-1), the pre-concentration efficiencies decreased to 33.9 ± 0.2 and 40.4 ± 5.4%, respectively. For environmental samples at cell densities of 2.7 × 105 and 6.6 × 107 cells·mL-1, the electrocoagulator maintained its pre-concentration efficiency at ~60%. On the other hand, the centrifuge’s pre-concentration efficiencies decreased to non-detectable and below 40%, respectively. This shows that the electrocoagulator outperformed the centrifuge when using eutrophic water samples. Finally, the compatibility of the electrocoagulator with the NanoGene assay was verified via the successful detection of the microcystin synthetase D (mcyD) gene in environmental samples. The viability of the electrocoagulator as an in situ compatible alternative to the centrifuge is also discussed.
Eun-Hee Lee; Beelee Chua; Ahjeong Son. Detection of Cyanobacteria in Eutrophic Water Using a Portable Electrocoagulator and NanoGene Assay. Environmental Science & Technology 2018, 52, 1375 -1385.
AMA StyleEun-Hee Lee, Beelee Chua, Ahjeong Son. Detection of Cyanobacteria in Eutrophic Water Using a Portable Electrocoagulator and NanoGene Assay. Environmental Science & Technology. 2018; 52 (3):1375-1385.
Chicago/Turabian StyleEun-Hee Lee; Beelee Chua; Ahjeong Son. 2018. "Detection of Cyanobacteria in Eutrophic Water Using a Portable Electrocoagulator and NanoGene Assay." Environmental Science & Technology 52, no. 3: 1375-1385.
We have demonstrated a palm-size NanoAptamer analyzer capable of detecting bisphenol A (BPA) at environmentally relevant concentrations (<1ng/mL or ppb). It is designed for performing reaction and fluorescence measurement on single cuvette sample. Modified NanoGene assay was used as the sensing mechanism where signaling DNA and QD was tethered to QD and magnetic bead via the aptamer. Aptamer affinity with BPA resulted in the release of the signaling DNA and QD from the complex and hence corresponding decrease in QD fluorescence measurement signal. Baseline characterization was first performed with empty cuvettes, quantum dots and magnetic beads under near-ideal conditions to establish essential functionality of the NanoAptamer analyzer. Duration of incubation time, number of rinse cycles, and necessity of cuvette vibration were also investigated. In order to demonstrate the capability of the NanoAptamer analyzer to detect BPA, samples with BPA concentrations ranging from 0.0005 to 1.0ng/mL (ppb) were used. The performance of the NanoAptamer analyzer was further examined by using laboratory protocol and commercial spectrofluorometer as reference. Correlation between NanoAptamer analyzer and laboratory protocol as well as commercial spectrofluorometer was evaluated via correlation plots and correlation coefficients.
Hyun Jeong Lim; Beelee Chua; Ahjeong Son. Detection of bisphenol A using palm-size NanoAptamer analyzer. Biosensors and Bioelectronics 2017, 94, 10 -18.
AMA StyleHyun Jeong Lim, Beelee Chua, Ahjeong Son. Detection of bisphenol A using palm-size NanoAptamer analyzer. Biosensors and Bioelectronics. 2017; 94 ():10-18.
Chicago/Turabian StyleHyun Jeong Lim; Beelee Chua; Ahjeong Son. 2017. "Detection of bisphenol A using palm-size NanoAptamer analyzer." Biosensors and Bioelectronics 94, no. : 10-18.
We demonstrated the detection of airborne bacteria by a disposable bio-precipitator and NanoGene assay combination. The bio-precipitator employed micro corona discharge at 1960 V and at less than 35 µA to simultaneously charge, capture and lyse the airborne bacteria. This was enabled by the use of a 15 μL liquid anode. Using a custom exposure setup, the target bacterium Bacillus subtilis in the atomization solution was rendered airborne. After exposure, the liquid anode in the bio-precipitator was subsequently measured for DNA concentration and analyzed with the NanoGene assay. As the bacterial concentration increased from 0.0104 to 42.6 g-DCW/L the released DNA concentration in the liquid anode increased from 2.10±1.57 to 75.00±7.15 ng/μL. More importantly, the NanoGene assay showed an increase in normalized fluorescence (gene quantification) from 18.03±1.18 to 49.71±1.82 as the bacterial concentrations increased from 0.0104 to 42.6 g-DCW/L. the electrical power consumption of the bio-precipitator was shown to be amenable for portable use. In addition, the detection limit of bio-precipitator and NanoGene assay combination in the context of environmentally relevant levels of airborne bacteria was also discussed.
Eun-Hee Lee; Beelee Chua; Ahjeong Son. Detection of airborne bacteria with disposable bio-precipitator and NanoGene assay. Biosensors and Bioelectronics 2016, 83, 205 -212.
AMA StyleEun-Hee Lee, Beelee Chua, Ahjeong Son. Detection of airborne bacteria with disposable bio-precipitator and NanoGene assay. Biosensors and Bioelectronics. 2016; 83 ():205-212.
Chicago/Turabian StyleEun-Hee Lee; Beelee Chua; Ahjeong Son. 2016. "Detection of airborne bacteria with disposable bio-precipitator and NanoGene assay." Biosensors and Bioelectronics 83, no. : 205-212.
We have demonstrated the sensing of airborne nanoparticles using a miniaturized Whipple double condenser (MWDC). Each condenser (17 mm long, 2.2 mm wide, and 1 mm tall) was fabricated using photolithography and copper electroplating. The MWDC was theoretically shown to function within the laminar flow regime and capable of detecting 10and 20-nm particles at a flow rate of 0.3 LPM. Monodispersed isopropyl alcohol and oleic acid airborne nanoparticles (10 and 20 nm) were generated using a TSI Model 9302 Single Jet Atomizer and TSI 3080 Electrostatic Classifier, and were electrically charged with 85 Kr isotope. The calculated and experimental particle pass through ratio (PPR) agreed reasonably well. Using a Keithley 616 electrometer, similar threshold condenser voltage (maximum second condenser current) was observed in both experimental PPR as well as the second condenser current versus condenser voltage plot. The MWDC also displayed characteristic Whipple curves in its experimental I/V versus kc plots. These data demonstrate the feasibility of the microfabricated double condenser design as the basis of a miniaturized nanoparticle sizing and counting device.
Terence Barrett; Beelee Chua; Britt A. Holmen. Sensing of Airborne Nanoparticles Using Miniaturized Whipple Double Condenser. IEEE Sensors Journal 2016, 16, 6990 -6996.
AMA StyleTerence Barrett, Beelee Chua, Britt A. Holmen. Sensing of Airborne Nanoparticles Using Miniaturized Whipple Double Condenser. IEEE Sensors Journal. 2016; 16 (18):6990-6996.
Chicago/Turabian StyleTerence Barrett; Beelee Chua; Britt A. Holmen. 2016. "Sensing of Airborne Nanoparticles Using Miniaturized Whipple Double Condenser." IEEE Sensors Journal 16, no. 18: 6990-6996.
To demonstrate and characterize a portable lysis apparatus for rapid single-step bacterial DNA extraction. Our portable lysis apparatus employed a novel design consisting of an annular piezo-element with perforated diaphragm. Using Bacillus subtilis as target bacteria, our portable lysis apparatus was able to achieve a normalized percent lysis as high as 66% within 30 sec. This is comparable to that by microprobe ultrasonication and almost 7 times higher than that by conventional bead beating. The effect from adding glass beads was predictable. However the results from the addition of sodium dodecyl sulfate (SDS) were counter-intuitive because a further increase from 0.5 to 1% concentration reduced the lysis performance. The portable lysis apparatus is also at least 1.5 to 5 times more power efficient than microprobe ultrasonication. Our portable lysis apparatus is capable of rapidly extracting bacterial DNA and is more power efficient than microprobe ultrasonication. The addition of glass beads or SDS concentration (up to 0.5%) improves its performance. The portable lysis apparatus provides a standalone, rapid, low cost and power efficient way of obtaining genomic constituents prior to a variety of bioassays used in the field of environmental, biomedical and other applied microbiology. This article is protected by copyright. All rights reserved.
Hyun Jeong Lim; Eun‐Hee Lee; Yeomin Yoon; Beelee Chua; Ahjeong Son. Portable lysis apparatus for rapid single-step DNA extraction of Bacillus subtilis. Journal of Applied Microbiology 2016, 120, 379 -387.
AMA StyleHyun Jeong Lim, Eun‐Hee Lee, Yeomin Yoon, Beelee Chua, Ahjeong Son. Portable lysis apparatus for rapid single-step DNA extraction of Bacillus subtilis. Journal of Applied Microbiology. 2016; 120 (2):379-387.
Chicago/Turabian StyleHyun Jeong Lim; Eun‐Hee Lee; Yeomin Yoon; Beelee Chua; Ahjeong Son. 2016. "Portable lysis apparatus for rapid single-step DNA extraction of Bacillus subtilis." Journal of Applied Microbiology 120, no. 2: 379-387.
A disposable bacterial lysis cartridge (BLC) and a sample handling system for the lysis ofBacillus subtiliswere constructed.
Eun-Hee Lee; Hyun Jeong Lim; Ahjeong Son; Beelee Chua. A disposable bacterial lysis cartridge (BLC) suitable for an in situ water-borne pathogen detection system. The Analyst 2015, 140, 7776 -7783.
AMA StyleEun-Hee Lee, Hyun Jeong Lim, Ahjeong Son, Beelee Chua. A disposable bacterial lysis cartridge (BLC) suitable for an in situ water-borne pathogen detection system. The Analyst. 2015; 140 (22):7776-7783.
Chicago/Turabian StyleEun-Hee Lee; Hyun Jeong Lim; Ahjeong Son; Beelee Chua. 2015. "A disposable bacterial lysis cartridge (BLC) suitable for an in situ water-borne pathogen detection system." The Analyst 140, no. 22: 7776-7783.
Eun-Hee Lee; Beelee Chua; Ahjeong Son. Micro corona discharge based cell lysis method suitable for inhibitor resistant bacterial sensing systems. Sensors and Actuators B: Chemical 2015, 216, 17 -23.
AMA StyleEun-Hee Lee, Beelee Chua, Ahjeong Son. Micro corona discharge based cell lysis method suitable for inhibitor resistant bacterial sensing systems. Sensors and Actuators B: Chemical. 2015; 216 ():17-23.
Chicago/Turabian StyleEun-Hee Lee; Beelee Chua; Ahjeong Son. 2015. "Micro corona discharge based cell lysis method suitable for inhibitor resistant bacterial sensing systems." Sensors and Actuators B: Chemical 216, no. : 17-23.