scholarly journals An aptamer-based magnetic flow cytometer using matched filtering

2020 ◽  
Vol 169 ◽  
pp. 112362
Author(s):  
Chih-Cheng Huang ◽  
Partha Ray ◽  
Matthew Chan ◽  
Xiahan Zhou ◽  
Drew A. Hall
Author(s):  
Chih-Cheng Huang ◽  
Xiahan Zhou ◽  
Da Ying ◽  
Drew A. Hall

2020 ◽  
Author(s):  
Chih-Cheng Huang ◽  
Partha Ray ◽  
Matthew Chan ◽  
Xiahan Zhou ◽  
Drew A. Hall

AbstractFacing unprecedented population-ageing, the management of noncommunicable diseases (NCDs) urgently needs a point-of-care (PoC) testing infrastructure. Magnetic flow cytometers are one such solution for rapid cancer cellular detection in a PoC setting. In this work, we report a giant magnetoresistive spin-valve (GMR SV) biosensor array with a multi-stripe sensor geometry and matched filtering to improve detection accuracy without compromising throughput. The carefully designed sensor geometry generates a characteristic signature when cells labeled with magnetic nanoparticles (MNPs) pass by thus enabling multi-parametric measurement like optical flow cytometers (FCMs). Enumeration and multi-parametric information were successfully measured across two decades of throughput. 10-µm polymer microspheres were used as a biomimetic model where MNPs and MNP-decorated polymer conjugates were flown over the GMR SV sensor array and detected with a signal-to-noise ratio (SNR) as low as 2.5 dB due to the processing gain afforded by the matched filtering. The performance was compared against optical observation, exhibiting a 92% detection efficiency. The system achieved a 95% counting accuracy for biomimetic models and 98% for aptamer-based pancreatic cancer cell detection. This system demonstrates the ability to perform reliable PoC diagnostics towards the benefit for NCD control plans.


1991 ◽  
Vol 66 (03) ◽  
pp. 350-354 ◽  
Author(s):  
Rob Fijnheer ◽  
Christa H E Homburg ◽  
Berend Hooibrink ◽  
Martine N Boomgaard ◽  
Dirk de Korte ◽  
...  

SummaryThrombin-induced changes in cytosolic free Ca2+ ([Ca2+]i) were studied in human platelets that had been stored for up to 6 days. Changes in [Ca2+]i were measured with Indo-1-loaded platelets and quantitated with two different methods: (i) measurement of the changes in total fluorescence; (ii) measurement of the [Ca2+]i changes in individual platelets in a flow cytometer, allowing the detection of non-responding platelets. The maximal concentration of [Ca2+]i after stimulation with 0.5 U of thrombin/ml decreased from 544 ± 58 nM (mean ± SEM, n = 6) on day 0, to 276 ± 9 nM on day 3 and to 203 ± 23 nM on day 6. The percentage of platelets responding to 0.5 U of thrombin/ml declined from 90 ± 2% on day 0 to 72 ± 4% on day 3, and to 47 ± 8% on day 6. Nevertheless, also the responding platelets showed a decreased rise in [Ca2+]i.The study shows that during platelet storage a decrease in the rise in [Ca2+]i upon thrombin stimulation occurs. This decrease is partly due to the formation of a subpopulation of platelets that is completely unresponsive and partly due to a decreased responsiveness in the remainder of the platelets; it is not due to a gradual decline in [Ca2+]i rise in all platelets. This phenomenon provides new insight in the functional defect of stored platelets.


1998 ◽  
Author(s):  
Mark Hyman ◽  
Iskender Sahin ◽  
Thai Nguyen
Keyword(s):  

2015 ◽  
Vol 4 (2) ◽  
pp. 37-50 ◽  
Author(s):  
V.Prabhakara Reddy ◽  
◽  
RAMACHANDRUNI V M S S KIRAN KUMAR ◽  
G.Viswanatha Reddy ◽  
P.Durga Prasad ◽  
...  

Vsyo o myase ◽  
2020 ◽  
pp. 56-60
Author(s):  
Zayko E.V. ◽  
◽  
Kuznetsova O.A. ◽  
Bataeva D.S. ◽  
Grudistova M.A. ◽  
...  

The problem of the uncontrolled use of antibiotics currently remains unresolved. Step-by-step monitoring of meat using modern methods will reduce the risk of using contaminated meat raw materials for food production. Qualitative monitoring will identify samples containing residual antimicrobial substances. The use of methods for identifying groups of antibiotics will help narrow the search for antibiotics by expensive chromatographic methods. A study was carried out of beef, pork and poultry meat, which is used in meat processing plants in the production of raw smoked sausages, using two methods. At the first stage, using a qualitative microbiological method, the raw meat was evaluated for the presence of antimicrobial substances, then their group was determined using a NovoCyte flow cytometer. According to the results of a study on a flow cytometer, it was found that out of 10 groups of antibiotics that can be determined by the tested method, the group of lincosamides was not found in all meat samples. The most common groups of chemotherapy drugs in pork were sulfonamides – 29.6 %, tetracycline group – 18.5 % and beta-lactams – 14.8 %, and in beef aminoglycosides – 36.7 %, phenicols – 30 % and beta-lactams – 13.3 %. In poultry meat samples, the most common were sulfonamides – 23.2 %, fenicols – 23.2 %, and beta-lactams – 16 %. Five groups of antibiotics were found in all studied types of meat: fenicols, β-lactams, macrolides, polypeptide antibiotics, and quinolones. This indicates their widespread use in animal husbandry and poultry farming.


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