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Acoustic Wave-Driven Functionalized Particles for Aptamer-Based Target Biomolecule Separation
Ahmad, Raheel,Destgeer, Ghulam,Afzal, Muhammad,Park, Jinsoo,Ahmed, Husnain,Jung, Jin Ho,Park, Kwangseok,Yoon, Tae-Sung,Sung, Hyung Jin American Chemical Society 2017 ANALYTICAL CHEMISTRY - Vol.89 No.24
<P>We developed a hybrid microfluidic device that utilized acoustic waves to drive functionalized microparticles inside a continuous flow microchannel and to separate particle-conjugated target proteins from a complex fluid. The acoustofluidic device is composed of an interdigitated transducer that produces high-frequency surface acoustic waves (SAW) and a polydimethylsiloxane (PDMS) microfluidic channel. The SAW interacted with the sample fluid inside the microchannel and deflected particles from their original streamlines to achieve separation. Streptavidin-functionalized polystyrene (PS) microparticles were used to capture aptamer (single-stranded DNA) labeled at one end with a biotin molecule. The free end of the customized aptamer15 (apt15), which was attached to the microparticles via streptavidin–biotin linkage to form the PS–apt15 conjugate, was used to capture the model target protein, thrombin (th), by binding at exosite I to form the PS–apt15–th complex. We demonstrated that the PS–apt15 conjugate selectively captured thrombin molecules in a complex fluid. After the PS–apt15–th complex was formed, the sample fluid was pumped through a PDMS microchannel along with two buffer sheath flows that hydrodynamically focused the sample flow prior to SAW exposure for PS–apt15–th separation from the non-target proteins. We successfully separated thrombin from mCardinal2 and human serum using the proposed acoustofluidic device.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2017/ancham.2017.89.issue-24/acs.analchem.7b03474/production/images/medium/ac-2017-03474b_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac7b03474'>ACS Electronic Supporting Info</A></P>
Ahmad, Raheel,Jang, Hyowon,Batule, Bhagwan S.,Park, Hyun Gyu American Chemical Society 2017 ANALYTICAL CHEMISTRY - Vol.89 No.17
<P>We have devised a barcode DNA-mediated signal amplifying strategy for ultrasensitive biomolecular detection by utilizing matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). As a model target, thrombin was first captured by specific aptamer15 functionalized on magnetic beads (MBs-apt15) and sandwiched through the simultaneous interaction with gold nanoparticles modified with another specific aptamer29 and barcode DNA molecules (apt29-AuNPs-bcDNAs). The sandwiched complex was collected by convenient magnetic separation and then treated with potassium cyanide (KCN) to dissolve the gold nanoparticles (AuNPs) and consequently release the barcode DNA molecules (bcDNAs), which were then again magnetically separated and analyzed by using MALDI-TOF MS. Under optimized conditions, this strategy revealed an excellent sensitivity with a limit of detection of 0.89 aM in a wide linear detection range from 0 aM to 0.1 nM and exhibited an acceptable recovery for thrombin detection in complex biological matrices. This signal amplifying strategy based on MALDI-TOF MS could greatly enable the ultrasensitive detection of various low abundant biomolecules.</P>
Evaluation of Tinda Gourd (Praecitrullus fistulosu) Germplasm's Yield
RAHEEL, Asfand,KHAN, Nasir Ahmad,BABAR, Raheel,ULLAH, Muhammad Arshad,ZAFFAR, Ali,IQBAL, Maouz,ASHRAF, Usman Korea FoodHealth Convergence Association 2019 식품보건융합연구 (KJFHC) Vol.5 No.3
The field experiment was conducted in vegetable area, Institute of Horticultural Sciences in University of Agriculture, Faisalabad in order to recognize morphological and fruit growth pattern and yield of Tinda (Praecitrullus fistulosus) gourd germplasm lines. Sixteen germplasm lines in which one line is used as check are included were sown and grown on flat beds in field. The field experiment was arranged as randomized complete block design (RCBD) with three replications. Data on days to maturity, fruit per vine, fruit weight in grams, fruit diameter and total yield obtained were recorded. The fruit texture is marked as phenotype parameter. All parameters were collected and then analyzed statistically. All lines and replications showed different results among each other according to parameter. The maximum DTM (days to maturity), F/P (fruit per plant), FW (fruit weight), FD (fruit diameter) and Yield were recorded was $L_0$ (68.66), $L_3$ (1.66), $L_{10}$ (248.33), $L_{13}$ (8.50) and $L_0$ (599.33) and the minimum were recorded was $L_1$ (56), $L_{11}$ (0.33), $L_0$ (198), $L_9$ (7) and $L_4$ (421) grams respectively. All lines showed smooth texture of fruits with no hairs when mature at harvesting stage.
Raheel Ahmad,Ghulam Destgeer,Muhammad Afzal,Husnain Ahmed,Jin Ho Jung,Jinsoo Park,Kwangseok Park,Hyung Jin Sung 한국가시화정보학회 2017 한국가시화정보학회 학술발표대회 논문집 Vol.2017 No.5
We designed a robust bio-chemo-mechanical hybrid system capable to capture and separate specific target molecules. The system composed of aptamer15 modified streptavidin-coated polystyrene microsphere (PSMs-apt15) and acoustofluidic device to show non-destructive target molecule separation. In this study, thrombin is selected as target molecule. First, the thrombin was captured by target-specific aptamer15 functionalized on PSMs (PSMs-apt15-thrombin) from a mixture of protein solution and separated with acoustofluidic device which consist of single-layered starting polydimethylsiloxane (PDMS) microchannel with interdigital transducer (IDT) patterned on lithium niobate (LiNbO3) substrate to produce high frequency (130 MHz) travelling surface acoustic waves (TSAWs). Once the IDT was actuated, the thrombin captured complex (PSMs-apt15-thrombin) were separated from the proteins solution due to the vertical component of acoustic radiation force, as >1 for green fluorescent microsphere and collected at outlet 2 by sheath focusing, while other proteins solution with some unbound thrombin passed through outlet 1. This hybrid system based on TSAWs could greatly enable the separation of various low abundant protein biomarkers.
Saeed Ahmad,Muhamad Aslam Pervez,Raheel Anwar,AnthonyKeth Thompson 한국원예학회 2006 Horticulture, Environment, and Biotechnology Vol.47 No.5
This research was carried out to investigate the effect of different thickness of polyethylene bags on ripening behavior and quality of ripe banana fruit. It was observed that bananas ripened in polyethylene packaging showed attractive fresh appearance with good eating quality. The effectiveness of ethylene in hastening of ripening was not reduced with CO₂ levels less than 5% and O₂ levels greater than 5% in polyethylene bags. Softness of banana fruits packed in polyethylene bags was directly proportional to weight loss. Packaging of fruit in polyethylene bags produced firmer bananas which could be beneficial in avoiding mechanical injury and some fungal infection and also extends the shelf life. Total soluble solids showed no significant difference regarding the polyethylene thickness. Packaging of bananas in 0.050 mm polyethylene bags extended the storage life of banana, but these received lower scores by panelists than those which were packed in 0.025 and 0.037 mm polyethylene bags. Packaging of bananas in 0.025 and 0.037 mm polyethylene bags was effective in achieving a more attractive appearance, freshness, and good flavor of ripe fruit than unpacked fruit and those packed in 0.050 mm polyethylene bags.
On-demand acoustic droplet splitting and steering in a disposable microfluidic chip
Park, Jinsoo,Jung, Jin Ho,Park, Kwangseok,Destgeer, Ghulam,Ahmed, Husnain,Ahmad, Raheel,Sung, Hyung Jin GENERAL AND APPLIED CHEMISTRY JOURNALS 2018 LAB ON A CHIP Vol. No.
<P>On-chip droplet splitting is one of the fundamental droplet-based microfluidic unit operations to control droplet volume after production and increase operational capability, flexibility, and throughput. Various droplet splitting methods have been proposed, and among them the acoustic droplet splitting method is promising because of its label-free operation without any physical or thermal damage to droplets. Previous acoustic droplet splitting methods faced several limitations: first, they employed a cross-type acoustofluidic device that precluded multichannel droplet splitting; second, they required irreversible bonding between a piezoelectric substrate and a microfluidic chip, such that the fluidic chip was not replaceable. Here, we present a parallel-type acoustofluidic device with a disposable microfluidic chip to address the limitations of previous acoustic droplet splitting devices. In the proposed device, an acoustic field is applied in the direction opposite to the flow direction to achieve multichannel droplet splitting and steering. A disposable polydimethylsiloxane microfluidic chip is employed in the developed device, thereby removing the need for permanent bonding and improving the flexibility of the droplet microfluidic device. We experimentally demonstrated on-demand acoustic droplet bi-splitting and steering with precise control over the droplet splitting ratio, and we investigated the underlying physical mechanisms of droplet splitting and steering based on Laplace pressure and ray acoustics analyses, respectively. We also demonstrated droplet tri-splitting to prove the feasibility of multichannel droplet splitting. The proposed on-demand acoustic droplet splitting device enables on-chip droplet volume control in various droplet-based microfluidic applications.</P>