A simple microfluidic 3D hydrodynamic flow focusing device has been developed and demonstrated quantitative determinations of quantum dot 525 with antibody (QD525-antibody) and hemagglutinin epitope tagged MAX (HA-MAX) protein concentrations. This device had a step depth cross junction structure at a hydrodynamic flow focusing point at which the analyte stream was flowed into a main detection channel and pinched not only horizontally but also vertically by two sheath streams. As a result, a triangular cross-sectional flow profile of the analyte stream was formed and the laser was focused on the top of the triangular shaped analyte stream. Since the detection volume was smaller than the radius of laser spot, a photon burst histogram showed Gaussian distribution, which was necessary for the quantitative analysis of protein concentration. By using this approach, a linear concentration curve of QD525-antibody down to 10 pM was demonstrated. In addition, the concentration of HA-MAX protein in HEK293 cell lysate was determined as 0.283 ± 0.015 nM. This approach requires for only 1 min determining protein concentration. As the best of our knowledge, this is the first time to determinate protein concentration by using single molecule detection techniques.
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http://dx.doi.org/10.1063/1.4730332 | DOI Listing |
Anal Chem
January 2025
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China.
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January 2025
Graduate School of Biotechnology, and College of Life Science, Kyung Hee University, Yongin-Si, 17104, Gyeonggi-Do, Republic of Korea.
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View Article and Find Full Text PDFBMC Urol
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Department of Urology and Guangdong Key Laboratory of Urology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510230, China.
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View Article and Find Full Text PDFJ Fluoresc
January 2025
Department of Applied Physics, School of Applied Natural Sciences, Adama Science and Technology University, PO Box 1888, Adama, Ethiopia.
In this research, the photophysical properties of metformin hydrochloride (MF-HCl) were studied using spectroscopic and molecular docking techniques. The interaction between metformin hydrochloride and caffeine is essential for understanding the pharmacokinetics of metformin, particularly in populations with high caffeine consumption. Metformin is a first-line medication for managing type 2 diabetes, while caffeine is a widely consumed dietary stimulant.
View Article and Find Full Text PDFProbiotics Antimicrob Proteins
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Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
The emergence of multidrug-resistant pathogens presents a significant global health challenge, which is primarily fuelled by overuse and misuse of antibiotics. Bacteria-derived antimicrobial metabolites offer a promising alternative strategy for combating antimicrobial resistance issues. Bacillus velezensis PD9 (BvPD9), isolated from stingless bee propolis, has been reported to have antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA).
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