Dried reagents for multiplex genotyping by tag-array minisequencing to be used in microfluidic devices

Ahlford, Annika; Kjeldsen, Bastian Gaardsvig; Reimers, Jakob Leffland; Lundmark, Anders; Romani, Massimo; Wolff, Anders; Syvänen, Ann Christine; Brivio, Monica

doi:10.1039/c0an00321b

Cited by 22 publications

(17 citation statements)

References 26 publications

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“…Hence, antibody denaturation most likely caused lower capture efficiency and detection sensitivity than the BWH results as we had anticipated. As a solution to this problem, it has been shown that sensitive immunologic and biochemical reagents in microfluidic systems (e.g., antibodies) can be lyophilized to significantly increase the shelf life of the test system [22], [23].…”

Section: Discussionmentioning

confidence: 99%

Enumeration of CD4+ T-Cells Using a Portable Microchip Count Platform in Tanzanian HIV-Infected Patients

et al. 2011

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BackgroundCD4+ T-lymphocyte count (CD4 count) is a standard method used to monitor HIV-infected patients during anti-retroviral therapy (ART). The World Health Organization (WHO) has pointed out or recommended that a handheld, point-of-care, reliable, and affordable CD4 count platform is urgently needed in resource-scarce settings.MethodsHIV-infected patient blood samples were tested at the point-of-care using a portable and label-free microchip CD4 count platform that we have developed. A total of 130 HIV-infected patient samples were collected that included 16 de-identified left over blood samples from Brigham and Women's Hospital (BWH), and 114 left over samples from Muhimbili University of Health and Allied Sciences (MUHAS) enrolled in the HIV and AIDS care and treatment centers in the City of Dar es Salaam, Tanzania. The two data groups from BWH and MUHAS were analyzed and compared to the commonly accepted CD4 count reference method (FACSCalibur system).ResultsThe portable, battery operated and microscope-free microchip platform developed in our laboratory (BWH) showed significant correlation in CD4 counts compared with FACSCalibur system both at BWH (r = 0.94, p<0.01) and MUHAS (r = 0.49, p<0.01), which was supported by the Bland-Altman methods comparison analysis. The device rapidly produced CD4 count within 10 minutes using an in-house developed automated cell counting program.ConclusionsWe obtained CD4 counts of HIV-infected patients using a portable platform which is an inexpensive (<$1 material cost) and disposable microchip that uses whole blood sample (<10 µl) without any pre-processing. The system operates without the need for antibody-based fluorescent labeling and expensive fluorescent illumination and microscope setup. This portable CD4 count platform displays agreement with the FACSCalibur results and has the potential to expand access to HIV and AIDS monitoring using fingerprick volume of whole blood and helping people who suffer from HIV and AIDS in resource-limited settings.

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Section: Discussionmentioning

confidence: 99%

Enumeration of CD4+ T-Cells Using a Portable Microchip Count Platform in Tanzanian HIV-Infected Patients

et al. 2011

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“…[28,47] Moreover, most products are provided as a lyophilized premix rather than liquid and separated components. [48][49][50][51] Compared with liquid reagents, lyophilized premix products have two advantages. First, lyophilized reagents can be preserved at room temperature, which decreases the requirement for cold chain transportation and storage.…”

Section: Poctmentioning

confidence: 99%

Nucleic Acid Testing for Coronavirus Disease 2019: Demand, Research Progression, and Perspective

Zhang

Wang

et al. 2020

Critical Reviews in Analytical Chemistry

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The current coronavirus disease 2019 (COVID-19) outbreak, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a public health emergency of international concern. There has been a surge in demand for COVID-19 diagnostic reagents, as timely detection of virus carriers is one of the most important components of disease prevention and control. Nucleic acid testing (NAT), with high sensitivity and specificity, is considered the "gold standard" for the diagnosis of COVID-19. Therefore, more than 700 research units and companies have been devoted to developing NAT reagents. To date, nearly 600 research units and companies have claimed to have completed the development of NAT reagents. The use of these products has a positive effect on disease prevention and control; however, exaggerated claims and inadequate understanding of the products have led to improper access to reagents and equipment in clinics. This has resulted in chaos in the clinical diagnosis of COVID-19. Herein, we have overviewed the COVID-19 NAT products, including their principles, corresponding advantages and disadvantages, relevant circumstances for application, and respective roles in epidemic containment. Our comments may provide some references for assay developers and aid clinical staff in choosing the appropriate class of test from the different tests available.

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“…Freeze-drying (lyophilization) is a low-temperature dehydration process mainly used for stabilizing of heat-labile biological drug substances contained in aqueous solutions [8]. Removing most of the water can prolong the shelf-life of the product as water drives many destabilization pathways [9,10]. Because freeze-dried reagents typically contain all of the necessary components for testing (at appropriate concentrations), errors associated with improper handling of wet reagents can also be reduced.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature-storable PCR mixes for SARS-CoV-2 detection

Wang

Zhong

et al. 2020

Clinical Biochemistry

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A novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) emerged in late 2019, causing an outbreak of pneumonia [coronavirus disease 2019 (COVID-19)] globally. Although the use of ready-made reaction mixes can enable more rapid PCR-based diagnosis of COVID-19, the need to transport and store these mixes at low temperatures presents challenges to already overburdened logistics networks. Methods: Here, we present an optimized freeze-drying procedure that allows SARS-CoV-2 PCR mixes to be transported and stored at ambient temperatures, without loss of activity. Additive-supplemented PCR mixes were freeze-dried. The residual moisture of the freeze-dried PCR mixes was measured by Karl-Fischer titration. Results: We found that the freeze-dried PCR mixes with~1.2% residual moisture are optimal for storage, transport, and reconstitution. The sensitivity, specificity, and repeatability of the freeze-dried reagents were similar to those of freshly prepared, wet reagents. The freeze-dried mixes retained activity at room temperature (18~25°C) for 28 days, and for 14 and 10 days when stored at 37°C and 56°C, respectively. Conclusion: The uptake of this approach will ease logistical challenges faced by transport networks and make more cold storage space available at diagnosis and hospital laboratories.

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Dried reagents for multiplex genotyping by tag-array minisequencing to be used in microfluidic devices

Cited by 22 publications

References 26 publications

Enumeration of CD4+ T-Cells Using a Portable Microchip Count Platform in Tanzanian HIV-Infected Patients

Enumeration of CD4+ T-Cells Using a Portable Microchip Count Platform in Tanzanian HIV-Infected Patients

Nucleic Acid Testing for Coronavirus Disease 2019: Demand, Research Progression, and Perspective

Room-temperature-storable PCR mixes for SARS-CoV-2 detection

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