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Zhang X, Wasserberg D, Breukers C, Connell BJ, Schipper PJ, van Dalum J, Baeten E, van den Blink D, Bloem AC, Nijhuis M, Wensing AMJ, Terstappen LWMM, Beck M. An inkjet-printed polysaccharide matrix for on-chip sample preparation in point-of-care cell counting chambers. RSC Adv 2020; 10:18062-18072. [PMID: 35517228 PMCID: PMC9053629 DOI: 10.1039/d0ra01645d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/28/2020] [Indexed: 01/28/2023] Open
Abstract
On-chip sample preparation in self-contained microfluidic devices is a key element to realize simple, low-cost, yet reliable in vitro diagnostics that can be carried out at the point-of-care (POC) with minimal training requirements by unskilled users. To address this largely unmet POC medical need, we have developed an optimized polysaccharide matrix containing the reagents which substantially improves our fully printed POC CD4 counting chambers for the monitoring of HIV patients. The simply designed counting chambers allow for capillary-driven filling with unprocessed whole blood. We carefully tailored a gellan/trehalose matrix for deposition by inkjet printing, which preserves the viability of immunostains during a shelf life of at least 3 months and enables controlled antibody release for intense and homogeneous immunofluorescent cell staining throughout the complete 60 mm2 image area within 30 min. Excellent agreement between CD4 counts obtained from our fully printed CD4 counting chambers and the gold standard, flow cytometry, is demonstrated using samples both from healthy donors and HIV-infected patients. Gellan/trehalose layers were tailored to optimize on-chip storage and release of antibodies in a simple point-of-care CD4 counting chip with excellent agreement with standard methods.![]()
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Wasserberg D, Zhang X, Breukers C, Connell BJ, Baeten E, van den Blink D, S O L À Benet È, Bloem AC, Nijhuis M, Wensing AMJ, Terstappen LWMM, Beck M. All-printed cell counting chambers with on-chip sample preparation for point-of-care CD4 counting. Biosens Bioelectron 2018; 117:659-668. [PMID: 30005387 DOI: 10.1016/j.bios.2018.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/27/2018] [Accepted: 07/01/2018] [Indexed: 12/19/2022]
Abstract
We demonstrate the fabrication of fully printed microfluidic CD4 counting chips with complete on-chip sample preparation and their applicability as a CD4 counting assay using samples from healthy donors and HIV-infected patients. CD4 counting in low-income and resource-limited point-of-care settings is only practical and affordable, if disposable tests can be fabricated at very low cost and all manual sample preparation is avoided, while operation as well as quantification is fully automated and independent of the skills of the operator. Here, we show the successful use of (inkjet) printing methods both to fabricate microfluidic cell counting chambers with controlled heights, and to deposit hydrogel layers with embedded fluorophore-labeled antibodies for on-chip sample preparation and reagent storage. The maturation process of gelatin after deposition prevents antibody wash-off during blood inflow very well, while temperature-controlled dissolution of the matrix ensures complete antibody release for immunostaining after the inflow has stopped. The prevention of antibody wash-off together with the subsequent complete antibody release guarantees a homogeneous fluorescence background, making rapid and accurate CD4 counting possible. We show the successful application of our fully printed CD4 counting chips on samples from healthy donors as well as from HIV-infected patients and find an excellent agreement between results from our method and from the gold standard, flow cytometry, in both cases.
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Affiliation(s)
- Dorothee Wasserberg
- Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Xichen Zhang
- Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Christian Breukers
- Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Bridgette J Connell
- University Medical Center Utrecht, Department of Medical Microbiology, Virology, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Ellen Baeten
- University Medical Center Utrecht, Laboratory of Translational Immunology, Section Diagnostics, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Dorine van den Blink
- University Medical Center Utrecht, Laboratory of Translational Immunology, Section Diagnostics, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Èlia S O L À Benet
- Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Andries C Bloem
- University Medical Center Utrecht, Laboratory of Translational Immunology, Section Diagnostics, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Monique Nijhuis
- University Medical Center Utrecht, Department of Medical Microbiology, Virology, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Annemarie M J Wensing
- University Medical Center Utrecht, Department of Medical Microbiology, Virology, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Leon W M M Terstappen
- Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Markus Beck
- Medical Cell Biophysics, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, PO Box 217, 7500 AE Enschede, The Netherlands.
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Zhang X, Wasserberg D, Breukers C, Terstappen LWMM, Beck M. Temperature-Switch Cytometry-Releasing Antibody on Demand from Inkjet-Printed Gelatin for On-Chip Immunostaining. ACS APPLIED MATERIALS & INTERFACES 2016; 8:27539-27545. [PMID: 27684590 DOI: 10.1021/acsami.6b09206] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Complete integration of all sample preparation steps in a microfluidic device greatly benefits point-of-care diagnostics. In the most simplistic approach, reagents are integrated in a microfluidic chip and dissolved upon filling with a sample fluid by capillary force. This will generally result in at least partial reagent wash-off during sample inflow. However, many applications, such as immunostaining-based cytometry, strongly rely on a homogeneous reagent distribution across the chip. The concept of initially preventing release (during inflow), followed by a triggered instantaneous and complete release on demand (after filling is completed) represents an elegant and simple solution to this problem. Here, we realize this controlled release by embedding antibodies in a gelatin layer integrated in a microfluidic chamber. The gelatin/antibody layer is deposited by inkjet printing. Maturation of this layer during the course of several weeks, due to the ongoing physical cross-linking of gelatin, slows down the antibody release, thereby reducing antibody wash-off during inflow, and consequently helping to meet the requirement for a homogeneous antibody distribution in the filled chamber. After inflow, complete antibody release is obtained by heating the gelatin layer above its sol-gel transition temperature, which causes the rapid dissolution of the entire gelatin/antibody layer at moderate temperatures. We demonstrate uniform and complete on-chip immunostaining of CD4 positive (CD4+) T-lymphocytes in whole blood samples, which is critical for accurate cell counts. The sample preparation is realized entirely on-chip, by applying temperature-switched antibody release from matured gelatin/antibody layers.
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Affiliation(s)
- Xichen Zhang
- Medical Cell Biophysics Group, MIRA Institute for Biomedical Engineering and Technical Medicine, Faculty of Science and Technology, University of Twente , Enschede 7522 NB, The Netherlands
| | - Dorothee Wasserberg
- Medical Cell Biophysics Group, MIRA Institute for Biomedical Engineering and Technical Medicine, Faculty of Science and Technology, University of Twente , Enschede 7522 NB, The Netherlands
| | - Christian Breukers
- Medical Cell Biophysics Group, MIRA Institute for Biomedical Engineering and Technical Medicine, Faculty of Science and Technology, University of Twente , Enschede 7522 NB, The Netherlands
| | - Leon W M M Terstappen
- Medical Cell Biophysics Group, MIRA Institute for Biomedical Engineering and Technical Medicine, Faculty of Science and Technology, University of Twente , Enschede 7522 NB, The Netherlands
| | - Markus Beck
- Medical Cell Biophysics Group, MIRA Institute for Biomedical Engineering and Technical Medicine, Faculty of Science and Technology, University of Twente , Enschede 7522 NB, The Netherlands
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