Development of a capillary flow microfluidic Escherichia coli biosensor with on-chip reagent delivery using water-soluble nanofibers

Jin, Sheng-Quan; Dai, Minhui; Ye, Bang‐Ce; Nugen, Sam R.

doi:10.1007/s00542-013-1742-y

Cited by 20 publications

(20 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11 However, the controlled dissolution of the reagent and on-chip mixing with the added sample is challenging. Especially in applications where the inflowing sample passes a reservoir of the reagent and slowly dissolves or washes out the stored reagent [12][13][14][15] , very precise control of the sample flow and the reagent release process is required. In contrast, mixing between sample and reagents in stopped flow applications can be realized simply by releasing the reagent with sufficient delay after the sample inflow has stopped at the required position on the chip.…”

Section: Introductionmentioning

confidence: 99%

Controlled antibody release from gelatin for on-chip sample preparation

Zhang¹,

Wasserberg²,

Breukers³

et al. 2016

Analyst

View full text Add to dashboard Cite

A practical way to realize on-chip sample preparation for point-of-care diagnostics is to store the required reagents on a microfluidic device and release them in a controlled manner upon contact with the sample. For the development of such diagnostic devices, a fundamental understanding of the release kinetics of reagents from suitable materials in microfluidic chips is therefore essential. Here, we study the release kinetics of fluorophore-conjugated antibodies from (sub-) µm thick gelatin layers and several ways to control the release time. The observed antibody release is well-described by a diffusion model. Release times ranging from ~20 s to ~650 s were determined for layers with thicknesses (in the dry state) between 0.25 µm and 1.5 µm, corresponding to a diffusivity of 0.65 µm 2 /s (in the swollen state) for our standard layer preparation conditions. By modifying the preparation conditions, we can influence the properties of gelatin to realize faster or slower release. Faster drying at increased temperatures leads to shorter release times, whereas slower drying at increased humidity yields slower release. As expected in a diffusive process, the release time increases with the size of the antibody. Moreover, the ionic strength of the release medium has a significant impact on the release kinetics. Applying these findings to cell counting chambers with on-chip sample preparation, we can tune the release to control the antibody distribution after inflow of blood in order to achieve homogeneous cell staining. IntroductionOne of the major fields of applications for microfluidics is in vitro diagnostics, with great potential particularly in point-of-care diagnostics. 1-3 Many process steps and sensing principles have been realized on microfluidic devices. 4 Recently, on-chip sample preparation using reagents stored in microfluidic devices has received more and more attention. 5 On-chip sample preparation can eliminate the dependence on external instrumentation for reagent delivery as well as benchtop sample treatment, thus integrating the complete test into one disposable. 6 To realize on-chip sample preparation, reagents are integrated in microfluidic devices and released upon contact with the inflowing sample. Compared with liquid reagents 7-10 , integrating dry reagents in microfluidic devices is beneficial for long-term storage and convenient for transportation, due to the better stability of reagents in the dry state. 11 However, the controlled dissolution of the reagent and on-chip mixing with the added sample is challenging. Especially in applications where the inflowing sample passes a reservoir of the reagent and slowly dissolves or washes out the stored reagent 12-15 , very precise control of the sample flow and the reagent release process is required. In contrast, mixing between sample and reagents in stopped flow applications can be realized simply by releasing the reagent with sufficient delay after the sample inflow has stopped at the required position on the chip. 16 To realize controlled reagen...

show abstract

Section: Introductionmentioning

confidence: 99%

Controlled antibody release from gelatin for on-chip sample preparation

Zhang¹,

Wasserberg²,

Breukers³

et al. 2016

Analyst

View full text Add to dashboard Cite

show abstract

“…+ 3*S. D. which is considered as the limit of detection), as shown in Table 1, we found that 10 0 cfu/ml has small overlap with the Blank Avg. + 3*S. D. Therefore, the lowest detectable cell concentration is 10 1 cfu/ml, which is comparable to other biosensor detection methods [19][20][21][22][30][31][32], and this method doesn't require sample pretreatment. These results indicate that the tri-nano biosensor design results in a sensitive and rapid detection system.…”

Section: A Functionalization Of Nanoparticlesmentioning

confidence: 58%

“…Sun et al [20] reported the photodeposition of nanoAg at TiO 2 -coated piezoelectric quartz crystal electrode to enhance the detection of E. coli DNA, with the detection limit of eight cells needed before PCR amplification. Cho and Irudayaraj [21] reported using immuno-AuNP network-based enzyme-linked immunosorbent assay (ELISA) biosensor with immuno-magnetic separation, which detected 3 cells/ml of E. [22] using a capillary flow microfluidic biosensor based nanofibers for reagent delivery and magnetic separation, which reported the detection limit of E. coli O157:H7 cells in culture at 10 6 cfu/ml. In this paper, we present an immunosensor consisting of three nanoparticles to detect E. coli O157:H7 cells in culture in 1 h. Signal amplification was conducted through lead sulfide (PbS) nanoparticles which were conjugated to AuNPs via oligonucleotide linkage.…”

mentioning

confidence: 99%

Electrochemical Immunosensor Using Nanoparticle-Based Signal Enhancement for <italic>Escherichia Coli</italic> O157:H7 Detection

2015

View full text Add to dashboard Cite

An electrochemical immunosensor based on the assembly of 3 nanoparticles for the rapid detection of Escherichia coli O157:H7 has been developed. The biosensor assay consists of magnetic separation using antibody-functionalized magnetic nanoparticles (MNPs) and electrochemical reporters using gold nanoparticle (AuNP)-conjugated lead sulfide (PbS) nanoparticles via oligonucleotide linkage. The gold nanoparticles (AuNPs) were also functionalized with polyclonal anti-E. coli O157:H7 antibodies in order to bind the target bacterial cells which were captured and separated from the sample by antibodyfunctionalized MNPs. Because each AuNP was linked to multiple PbS nanoparticles, each binding event to the target resulted in substantial amplification. The signal of PbS was measured on screen-printed carbon electrode (SPCE) by square wave anodic stripping voltammetry (SWASV). Results show that the biosensor could detect E. coli O157:H7 in the range of 10 1 to 10 6 colony forming units per milliliter (cfu/ml) with a signal-to-noise ratio ranging from 2.77 to 4.31. With sample preparation being minimized, results were obtained in 1 h from sample processing to final readout. Due to its high sensitivity, this tri-nano immunosensor has great potential applications in public health, biodefense, and food/water safety monitoring.

show abstract

“…Compared with the passive release scheme, this active release scheme offers better temporal control for the onchip sample preparation and can be beneficial for other biological assays, which requires a series of mixing steps. A similar concept was reported by Jin and co-workers [70], who achieved on-chip antibody release via the dissolution of poly(vinylpyrrolidone) (PVP) nanofibers for E. coli identification. Another approach to trigger the release of reagents for on-chip sample preparation is pH-responsive release.…”

Section: On-chip Immunostaining and Cell Identificationmentioning

confidence: 72%