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1.
Lab Chip ; 22(9): 1805-1814, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35322844

RESUMO

Antimicrobial susceptibility testing (AST) is a key measure in clinical microbiology laboratories to enable appropriate antimicrobial administration. During an AST, the determination of the minimum inhibitory concentration (MIC) is an important step in which the bacterial responses to an antibiotic at a series of concentrations obtained in separate bacterial growth chambers or sites are compared. However, the preparation of different antibiotic concentrations is time-consuming and labor-intensive. In this paper, we present a microfluidic device that generates a concentration gradient for antibiotics that is produced by diffusion in the laminar flow regime along a series of lateral microwells to encapsulate bacteria for antibiotic treatment. All the AST preparation steps (including bacterium loading, antibiotic concentration generation, buffer washing, and isolated bacterial growth with an antibiotic) can be performed in a single chip. The viable bacterial cells in each microwell after the antibiotic treatment are then quantified by their surface-enhanced Raman scattering (SERS) signals that are acquired after placing a uniform SERS-active substrate in contact with all the microwells. For proof-of-concept, we demonstrated the AST performance of this system on ampicillin (AMP)-susceptible and -resistant E. coli strains. Compared with the parameters for conventional AST methods, the AST procedure based on this chip requires only 20 µL of bacteria solution and 5 h of operation time. This result indicates that this integrated system can greatly shorten and simplify the tedious and labor-intensive procedures required for current standard AST methods.


Assuntos
Antibacterianos , Anti-Infecciosos , Antibacterianos/farmacologia , Bactérias , Escherichia coli , Dispositivos Lab-On-A-Chip , Testes de Sensibilidade Microbiana , Microfluídica/métodos , Análise Espectral Raman
2.
Biosens Bioelectron ; 191: 113463, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34198171

RESUMO

An osmium-coated lensed fiber (OLF) probe combined with a silver-coated black silicon (SBS) substrate was used to generate a dielectrophoretic (DEP) force that traps bacteria and enables Raman signal detection from bacteria. The lensed fiber coated with a 2-nm osmium layer was used as an electrode for the DEP force and also as a lens to excite Raman signals. The black silicon coated with a 150-nm silver layer was used both as the surface-enhanced Raman scattering (SERS) substrate and the counter electrode. The enhanced Raman signal was collected by the same OLF probe and further analyzed with a spectrometer. For Raman measurements, a drop of bacterial suspension was placed between the OLF probe and the SBS substrate. By controlling the frequency of an AC voltage on the OLF probe and SBS substrate, a DEP force at 1 MHz concentrated bacteria on the SBS surface and removed the unbound micro-objects in the solution at 1 kHz. A bacteria concentration of 6 × 104 CFU/mL (colony forming units per mL) could be identified in less than 15 min, using a volume of only 1 µL, by recording the variation of the Raman peak at 740 cm-1.


Assuntos
Técnicas Biossensoriais , Silício , Bactérias , Análise Espectral Raman
3.
Biosens Bioelectron ; 191: 113483, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34246896

RESUMO

Bloodstream infection (BSI) is a serious public health issue worldwide. Timely and effective antibiotics for controlling infection are crucial towards patient outcomes. However, the current culture-based methods of identifying bacteria and antimicrobial susceptibility testing (AST) remain labor-intensive and time-consuming, and are unable to provide early support to physicians in critical hours. To improve the effectiveness of early antibiotic therapy, Surface-enhanced Raman scattering (SERS) technology, has been used in bacterial detection and AST based on its high specificity and label-free features. To simplify sample preparation steps in SERS-AST, we proposed an automated microfluidic control system to integrate all required procedures into a single device. Our preliminary results demonstrated the system can achieve on-chip reagent replacement, bacteria trapping, and buffer exchange. Finally, in-situ SERS-AST was performed within 3.5 h by loading isolates of ampicilin susceptible and resistant E. coli and clear discrimination of two strains under antibiotic treatment was demonstrated. Overall, our system can standardize and simplify the SERS-AST protocol and implicate parallel bacterial detection. This prototypical integration demonstrates timely microbiological support to optimize early antibiotic therapy for fighting bacteremia.


Assuntos
Técnicas Biossensoriais , Microfluídica , Antibacterianos/farmacologia , Escherichia coli , Humanos , Testes de Sensibilidade Microbiana , Análise Espectral Raman
4.
Biosensors (Basel) ; 11(3)2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33800935

RESUMO

Surface Plasmon Resonance (SPR) is widely used in biological and chemical sensing with fascinating properties. However, the application of SPR to detect trace targets is hampered by non-specific binding and poor signal. A variety of approaches for amplification have been explored to overcome this deficiency including DNA aptamers as versatile target detection tools. Hybridization chain reaction (HCR) is a high-efficiency enzyme-free DNA amplification method operated at room temperature, in which two stable species of DNA hairpins coexist in solution until the introduction of the initiator strand triggers a cascade of hybridization events. At an optimal salt condition, as the concentrations of H1 and H2 increased, the HCR signals were enhanced, leading to signal amplification reaching up to 6.5-fold of the detection measure at 30 min. This feature enables DNA to act as an amplifying transducer for biosensing applications to provide an enzyme-free alternative that can easily detect complex DNA sequences. Improvement of more diverse recognition events can be achieved by integrating HCR with a phase-sensitive SPR (pSPR)-tested aptamer stimulus. This work seeks to establish pSPR aptamer system for highly informative sensing by means of an amplification HCR. Thus, combining pSPR and HCR technologies provide an expandable platform for sensitive biosensing.


Assuntos
Técnicas Biossensoriais , Hibridização de Ácido Nucleico , Ressonância de Plasmônio de Superfície , Aptâmeros de Nucleotídeos/química , DNA/química , Ouro/química , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico
5.
Biosensors (Basel) ; 10(12)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33353033

RESUMO

This article reviews optical biosensors and their integration with microfluidic channels. The integrated biosensors have the advantages of higher accuracy and sensitivity because they can simultaneously monitor two or more parameters. They can further incorporate many functionalities such as electrical control and signal readout monolithically in a single semiconductor chip, making them ideal candidates for point-of-care testing. In this article, we discuss the applications by specifically looking into point-of-care testing (POCT) using integrated optical sensors. The requirement and future perspective of integrated optical biosensors for POC is addressed.


Assuntos
Técnicas Biossensoriais , Dispositivos Lab-On-A-Chip , Testes Imediatos , Desenho de Equipamento , Técnicas Analíticas Microfluídicas , Análise de Sequência com Séries de Oligonucleotídeos , Sistemas Automatizados de Assistência Junto ao Leito , Semicondutores
6.
Anal Methods ; 12(26): 3318-3332, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32930218

RESUMO

Whole blood analysis reveals crucial information about various physiological and pathological conditions, including cancer metastasis, infection, and immune status, among others. Despite this rich information, the complex composition of whole blood usually required multiple sample preparation steps to purify targeted analytes. Traditionally, whole blood preparation processes, including centrifugation, lysis, dilution, or staining, are usually manually operated by well-trained technicians using bench-top instruments. This preparation can require a large blood volume and cannot be directly integrated with detection systems. Recently, various studies have integrated microfluidics with electrical sensors for whole blood analysis, with a focus on cell-based analysis, such as cell type, number, morphology, phenotype, and secreted molecules. These miniaturized systems require less sample and shorter reaction times. Besides, the sample processing and analysis can be fully integrated and automated with minimal operations. We believe these systems can transfer the current whole blood analysis from hospitals or laboratories into clinics or home settings to enable real-time and continuous health condition monitoring in point-of-care settings.


Assuntos
Microfluídica , Sistemas Automatizados de Assistência Junto ao Leito , Centrifugação , Testes Hematológicos , Manejo de Espécimes
7.
Analyst ; 145(23): 7654-7661, 2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-32966364

RESUMO

Inflammation is a complex biological response of the human body to external or internal stimuli, such as invading pathogens, defective cells, or irritating substances. One important indicator of inflammatory conditions or the progress of various diseases, such as cancer, cardiovascular diseases, neurological diseases, connective tissue diseases, sepsis, or Alzheimer's disease, is the concentration level of inflammatory biomarkers, including immunoglobulins, cytokines, and C-reactive protein (CRP). Since inflammatory biomarkers are highly correlated with each other, it is important to measure them simultaneously. To enable continuous and dynamic inflammatory biomarker detection, we utilized localized surface plasmon resonance (LSPR) to perform label-free molecule sensing. Since the LSPR sensing mechanism requires only a small sensing area with simplified optical setup, it can be easily integrated with a microfluidic device. To simplify reagent operation complexity, we developed an automated microfluidic control system to control reagent guiding and switching in the immunoassay with less manual processes and potential operation errors. Our results successfully demonstrated multiplex IgG, TNF-α, and CRP measurement with only 60 µL assay volume and 3.5 h assay time. In each test, 20 sensing spot measurements under four different reagent conditions can be performed. Overall, we envision that the LSPR sensor integrated automated microfluidic control system could perform rapid, multiplex, and multiparallel continuous inflammatory biomarker detection, which would be beneficial for various applications, such as immune status monitoring, diagnosis and prognosis of inflammatory diseases.


Assuntos
Técnicas Biossensoriais , Ressonância de Plasmônio de Superfície , Biomarcadores , Ouro , Humanos , Imunoensaio , Dispositivos Lab-On-A-Chip , Microfluídica
8.
Lab Chip ; 20(14): 2520-2528, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32542276

RESUMO

The antibiotic susceptibility test (AST) is a general laboratory procedure for bacterial identification and characterization and can be utilized to determine effective antimicrobials for individual patients. Due to the low bacterial concentration, conventional AST usually requires a prolonged bacterial culture time and a labor-intensive sample pretreatment process. Therefore, it cannot perform timely diagnosis or treatment, which results in a high mortality rate for seriously infected patients. To address this problem, we developed a microfluidic microwell device integrating surface-enhanced Raman scattering (SERS) technology, or the so called the Microwell-SERS system, to enable a rapid and high-throughput AST. Our results show that the Microwell-SERS system can successfully encapsulate bacteria in a miniaturized microwell with a greatly increased effective bacteria concentration, resulting in a shorter bacterial culture time. By attaching a microchannel onto the microwell, a smooth liquid and air exchange can purify the surrounding buffer and isolate bacteria in an individual microwell for independent SERS measurement. For proof-of-concept, we demonstrated a 2 h AST on susceptible and resistant E. coli and S. aureus with a concentration of 103 CFU mL-1 in the Microwell-SERS system, whereas the previous SERS-AST method required 108 CFU mL-1 bacterial suspension droplets dispensing on a SERS substrate. Based on the above features, we envision that the Microwell-SERS system could achieve highly sensitive, label-free, bacteria detection and rapid AST to enable timely and accurate bacterial infection disease diagnosis.


Assuntos
Análise Espectral Raman , Staphylococcus aureus , Antibacterianos/farmacologia , Bactérias , Escherichia coli , Humanos , Microfluídica
9.
Anal Chem ; 91(17): 10988-10995, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31387345

RESUMO

Antibiotic susceptibility test (AST) is essential in clinical diagnosis of serious bacterial infection, such as sepsis, while it typically takes 2-5 days for sample culture, antibiotic treatment, and reading result. Detecting metabolites secreted from bacteria with surface-enhanced Raman scattering (SERS) enables rapid determination of antibiotic susceptibility, reducing the AST time to 1-2 days. However, it still requires 1 day of culture time to obtain sufficient quantity of bacteria for sample washing, bacterial extraction, and antibiotic treatment. Additionally, the whole procedure, manually performed in open environment, often suffers from contamination and human error. To address the above problems, a microfluidic system integrating membrane filtration and the SERS-active substrate (MF-SERS) was developed to perform on-chip bacterial enrichment, metabolite collection, and in situ SERS measurements for antibiotic susceptibility test. Using Escherichia coli as the prototype bacterium, the lowest SERS detection limit of bacterial concentration of the MF-SERS system is 103 CFU/mL, which is 4 orders of magnitude lower than that using centrifugation-purification procedure, significantly shortening the bacterial culture time. The bacteria and secreted metabolites are enclosed during bacterial trapping, metabolite filtration, and SERS detection, thus minimizing possible contamination and human errors. Finally, the successful demonstration of AST on E. coli with a concentration of 103 CFU/mL is presented. Overall, the MF-SERS system with a miniature size and well-confined microenvironment allows the integration of multiple bacteria processes for bacterial enrichment, culture, and determination of AST.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Canamicina/farmacologia , Dispositivos Lab-On-A-Chip , Testes de Sensibilidade Microbiana/instrumentação , Análise Espectral Raman/métodos , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Filtração/métodos , Limite de Detecção , Membranas Artificiais , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/metabolismo
10.
Biomicrofluidics ; 13(1): 014105, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30867876

RESUMO

The primary cilium plays an important role in mechanosensation in mammalian cells. To understand mechanosensation in the primary cilium, we combined a microfluidic device with super-resolution microscopy to study the primary cilium phenotypes. The microfluidic system enabled the precise control of the flow shear within a well-confined cell-culture environment. In addition, in situ cilia fixation was possible by switching from the culture medium to the fixation buffer instantaneously, which preserved the real-time cilium phenotype under the flow shear. After fixation, multiple cilium-specific proteins were immunostained to quantify the cilia bending behavior. We found that >50% of the primary cilia of mouse inner medullary collecting duct cells were highly aligned with the direction of flow under 11 Pa shear stress. Finally, we used super-resolution microscopy to observe the redistribution of two major cilium-specific proteins under flow shear, acetylated alpha-tubulin, and intraflagellar transport protein 88. To the best of our knowledge, this is the first platform to combine a microfluidic device with super-resolution microscopy to enable flow stimulation and in situ fixation for the observation of ciliary protein. This system can potentially be applied to the future development of a stimulation-enabled organ-on-a-chip to observe the intercellular signaling of primary cilia or for the analysis of disease mechanisms associated with ciliary mutations at the organ level.

11.
Sci Rep ; 8(1): 15345, 2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30337656

RESUMO

This study reports a microfluidic device for whole blood processing. The device uses the bifurcation law, cross-flow method, and hydrodynamic flow for simultaneous extraction of plasma, red blood cells, and on-chip white blood cell trapping. The results demonstrate successful plasma and red blood cell collection with a minimum dilution factor (0.76x) and low haemolysis effect. The extracted red blood cells can also be applied for blood type tests. Moreover, the device can trap up to ~1,800 white blood cells in 20 minutes. The three components can be collected simultaneously using only 6 µL of whole blood without any sample preparation processes. Based on these features, the microfluidic device enables low-cost, rapid, and efficient whole blood processing functionality that could potentially be applied for blood analysis in resource-limited environments or point-of-care settings.


Assuntos
Separação Celular/instrumentação , Eritrócitos/química , Dispositivos Lab-On-A-Chip/normas , Leucócitos/química , Técnicas Analíticas Microfluídicas/instrumentação , Plasma/química , Desenho de Equipamento , Contagem de Eritrócitos , Humanos
12.
Analyst ; 143(6): 1367-1377, 2018 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-29423467

RESUMO

In this study, we developed an automated microfluidic DNA microarray (AMDM) platform for point mutation detection of genetic variants in inherited arrhythmic diseases. The platform allows for automated and programmable reagent sequencing under precise conditions of hybridization flow and temperature control. It is composed of a commercial microfluidic control system, a microfluidic microarray device, and a temperature control unit. The automated and rapid hybridization process can be performed in the AMDM platform using Cy3 labeled oligonucleotide exons of SCN5A genetic DNA, which produces proteins associated with sodium channels abundant in the heart (cardiac) muscle cells. We then introduce a graphene oxide (GO)-assisted DNA microarray hybridization protocol to enable point mutation detection. In this protocol, a GO solution is added after the staining step to quench dyes bound to single-stranded DNA or non-perfectly matched DNA, which can improve point mutation specificity. As proof-of-concept we extracted the wild-type and mutant of exon 12 and exon 17 of SCN5A genetic DNA from patients with long QT syndrome or Brugada syndrome by touchdown PCR and performed a successful point mutation discrimination in the AMDM platform. Overall, the AMDM platform can greatly reduce laborious and time-consuming hybridization steps and prevent potential contamination. Furthermore, by introducing the reciprocating flow into the microchannel during the hybridization process, the total assay time can be reduced to 3 hours, which is 6 times faster than the conventional DNA microarray. Given the automatic assay operation, shorter assay time, and high point mutation discrimination, we believe that the AMDM platform has potential for low-cost, rapid and sensitive genetic testing in a simple and user-friendly manner, which may benefit gene screening in medical practice.


Assuntos
Arritmias Cardíacas/genética , Técnicas Analíticas Microfluídicas , Análise de Sequência com Séries de Oligonucleotídeos , Arritmias Cardíacas/diagnóstico , Análise Mutacional de DNA , Humanos , Canal de Sódio Disparado por Voltagem NAV1.5/genética , Hibridização de Ácido Nucleico , Oligonucleotídeos , Mutação Puntual
13.
J Formos Med Assoc ; 117(9): 841-848, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29129647

RESUMO

BACKGROUND/PURPOSE: This study aimed at screening the diagnostic potential of salivary biomarkers and pairing them to establish a prediction model with higher accuracy in diagnosing periodontitis in the Taiwanese population. METHODS: Fifty-seven participants were divided into a non-periodontitis group and a periodontitis group. Salivary biomarkers CRP, IL-6, IL-8, IL-1ß, IL-1ra, lactoferrin, MMP-8, MMP-9, PDGF-BB, TNF-α, and VEGF, were analyzed. The potential and reliability of the biomarkers for diagnosing periodontitis were analyzed dichotomously. The correlation of individual biomarkers with periodontitis was assessed using the Spearman rank correlation coefficient with logistic regression. The combinational prediction model was evaluated using the area under the receiver operating characteristic curve (AUC). RESULTS: Regarding individual biomarkers, IL-1ß and MMP-9 levels were significantly higher, and TNF-α was significantly lower in the periodontitis group. IL-1ß, MMP-8, and MMP-9 exhibited a greater odds ratio with statistical significance in the dichotomous table. The combination of three biomarkers yielded AUCs of 0.821-0.853, and the combination of IL-1ß, IL-1ra, and MMP-9 exhibited the highest AUC (0.853), with high sensitivity (73.3%) and specificity (88.9%). CONCLUSION: Regarding individual biomarkers, IL-1ß, MMP-8, and MMP-9 showed potential for identifying patients with periodontitis. The combination of IL-1ß, IL-1ra, and MMP-9 might be feasible for developing a future point-of-care device for diagnosing periodontitis.


Assuntos
Biomarcadores/análise , Periodontite/diagnóstico , Saliva/química , Adulto , Idoso , Feminino , Humanos , Proteína Antagonista do Receptor de Interleucina 1/análise , Interleucina-1beta/análise , Modelos Logísticos , Masculino , Metaloproteinase 9 da Matriz/análise , Pessoa de Meia-Idade , Curva ROC , Reprodutibilidade dos Testes , Taiwan , Adulto Jovem
14.
Sensors (Basel) ; 17(12)2017 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-29186872

RESUMO

Coronary artery disease and its related complications pose great threats to human health. In this work, we aim to clinically evaluate a CMOS field-effect biomolecular sensor for cardiac biomarkers, cardiac-specific troponin-I (cTnI), N-terminal prohormone brain natriuretic peptide (NT-proBNP), and interleukin-6 (IL-6). The CMOS biosensor is implemented via a standard commercialized 0.35 µm CMOS process. To validate the sensing characteristics, in buffer conditions, the developed CMOS biosensor has identified the detection limits of IL-6, cTnI, and NT-proBNP as being 45 pM, 32 pM, and 32 pM, respectively. In clinical serum conditions, furthermore, the developed CMOS biosensor performs a good correlation with an enzyme-linked immuno-sorbent assay (ELISA) obtained from a hospital central laboratory. Based on this work, the CMOS field-effect biosensor poses good potential for accomplishing the needs of a point-of-care testing (POCT) system for heart disease diagnosis.


Assuntos
Técnicas Biossensoriais , Biomarcadores , Doença da Artéria Coronariana , Humanos , Peptídeo Natriurético Encefálico , Fragmentos de Peptídeos , Troponina I
15.
Nanomaterials (Basel) ; 7(5)2017 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-28468325

RESUMO

Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR)-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins detection. However, the sensor fabrication process is usually slow and complicated, so it is not accessible for large-area and batch fabrication. Herein, we report a large-area (2 cm × 2 cm) nanofabrication method using physical vapor deposition followed by a rapid thermal annealing treatment. To optimize the sensor performance, we systematically characterized three fabrication conditions, including (1) the deposition thickness; (2) the maximum annealing temperature, and (3) the annealing time. The corresponding absorbance spectrum profile and surface morphology of the nanostructures were observed by a UV-VIS spectrometer and atomic force microscopy. We then tested the sensitivity of the sensor using a glucose solution at different concentrations. The results showed that the sensor with 10 nm gold deposition thickness under 5-min 900 °C rapid thermal annealing can achieve the highest sensitivity (189 nm RIU-1). Finally, we integrated this nanoplasmonic sensor with a microchannel and a motorized stage to perform a 10-spot immunoglobulin detection in 50 min. Based on its real-time, dynamic and multi-point analyte detection capability, the nanoplasmonic sensor has the potential to be applied in high-throughput or multiplex immunoassay analysis, which would be beneficial for disease diagnosis or biomedical research in a simple and cost-effective platform.

16.
Lab Chip ; 16(16): 3105-13, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27314254

RESUMO

The hemoglobin-A1c test, measuring the ratio of glycated hemoglobin (HbA1c) to hemoglobin (Hb) levels, has been a standard assay in diabetes diagnosis that removes the day-to-day glucose level variation. Currently, the HbA1c test is restricted to hospitals and central laboratories due to the laborious, time-consuming whole blood processing and bulky instruments. In this paper, we have developed a microfluidic device integrating dual CMOS polysilicon nanowire sensors (MINS) for on-chip whole blood processing and simultaneous detection of multiple analytes. The micromachined polymethylmethacrylate (PMMA) microfluidic device consisted of a serpentine microchannel with multiple dam structures designed for non-lysed cells or debris trapping, uniform plasma/buffer mixing and dilution. The CMOS-fabricated polysilicon nanowire sensors integrated with the microfluidic device were designed for the simultaneous, label-free electrical detection of multiple analytes. Our study first measured the Hb and HbA1c levels in 11 clinical samples via these nanowire sensors. The results were compared with those of standard Hb and HbA1c measurement methods (Hb: the sodium lauryl sulfate hemoglobin detection method; HbA1c: cation-exchange high-performance liquid chromatography) and showed comparable outcomes. Finally, we successfully demonstrated the efficacy of the MINS device's on-chip whole blood processing followed by simultaneous Hb and HbA1c measurement in a clinical sample. Compared to current Hb and HbA1c sensing instruments, the MINS platform is compact and can simultaneously detect two analytes with only 5 µL of whole blood, which corresponds to a 300-fold blood volume reduction. The total assay time, including the in situ sample processing and analyte detection, was just 30 minutes. Based on its on-chip whole blood processing and simultaneous multiple analyte detection functionalities with a lower sample volume requirement and shorter process time, the MINS device can be effectively applied to real-time diabetes diagnostics and monitoring in point-of-care settings.


Assuntos
Análise Química do Sangue/instrumentação , Dispositivos Lab-On-A-Chip , Nanofios/química , Algoritmos , Biomarcadores/sangue , Simulação por Computador , Diabetes Mellitus/sangue , Desenho de Equipamento , Hemoglobina A Glicada/análise , Hemoglobinas/análise , Humanos , Microscopia Eletrônica de Varredura , Nanofios/ultraestrutura , Reprodutibilidade dos Testes , Compostos de Silício/química , Propriedades de Superfície
17.
Adv Drug Deliv Rev ; 95: 90-103, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26408791

RESUMO

Systemic inflammatory disorders resulting from infection, trauma, surgery, and severe disease conditions pose serious threats to human health leading to organ dysfunction, organ failure, and mortality. The highly complex and dynamic nature of the immune system experiencing acute inflammation makes immunomodulatory therapy blocking pro-inflammatory cytokines very challenging. Successful therapy requires the ability to determine appropriate anti-cytokine drugs to be delivered at a right dose in a timely manner. Label-free micro- and nano-biosensors hold the potential to overcome the current challenges, enabling cytokine-targeted treatments to be tailored according to the immune status of an individual host with their unique cytokine biomarker detection capabilities. This review studies the recent progress in label-free cytokine biosensors, summarizes their performances and potential merits, and discusses future directions for their advancements to meet challenges towards personalized anti-cytokine drug delivery.


Assuntos
Técnicas Biossensoriais , Citocinas/imunologia , Inflamação/terapia , Humanos , Imunoensaio , Inflamação/imunologia , Microfluídica , Nanomedicina , Medicina de Precisão
18.
Technology (Singap World Sci) ; 2(2): 176, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25083509

RESUMO

Quantitative measurement of protein biomarkers is critical for biomarker validation and early disease detection. Current multiplex immunoassays are time consuming costly and can suffer from low accuracy. For example, multiplex ELISAs require multiple, tedious, washing and blocking steps. Moreover, they suffer from nonspecific antibody cross-reactions, leading to high background and false-positive signals. Here, we show that co-localizing antibody-bead pairs in an aqueous two-phase system (ATPS) enables multiplexing of sensitive, no-wash, homogeneous assays, while preventing nonspecific antibody cross-reactions. Our cross-reaction-free, multiplex assay can simultaneously detect picomolar concentrations of four protein biomarkers ((C-X-C motif) ligand 10 (CXCL10), CXCL9, interleukin (IL)-8 and IL-6) in cell supernatants using a single assay well. The potential clinical utility of the assay is demonstrated by detecting diagnostic biomarkers (CXCL10 and CXCL9) in plasma from 88 patients at the onset of the clinical symptoms of chronic graft-versus-host disease (GVHD).

19.
Lab Chip ; 14(7): 1230-45, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24525555

RESUMO

Cellular analysis plays important roles in various biological applications, such as cell biology, drug development, and disease diagnosis. Conventional cellular analysis usually measures the average response from a whole cell group. However, bulk measurements may cause misleading interpretations due to cell heterogeneity. Another problem is that current cellular analysis may not be able to differentiate various subsets of cell populations, each exhibiting a different behavior than the others. Single-cell analysis techniques are developed to analyze cellular properties, conditions, or functional responses in a large cell population at the individual cell level. Integrating optics with microfluidic platforms provides a well-controlled microenvironment to precisely control single cell conditions and perform non-invasive high-throughput analysis. This paper reviews recent developments in optofluidic technologies for various optics-based single-cell analyses, which involve single cell manipulation, treatment, and property detection. Finally, we provide our views on the future development of integrated optics with microfluidics for single-cell analysis and discuss potential challenges and opportunities of this emerging research field in biological applications.


Assuntos
Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/métodos , Técnicas Analíticas Microfluídicas/tendências , Retratos como Assunto
20.
ACS Nano ; 8(3): 2667-76, 2014 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-24568576

RESUMO

Localized surface plasmon resonance (LSPR) nanoplasmonic effects allow for label-free, real-time detection of biomolecule binding events on a nanostructured metallic surface with simple optics and sensing tunability. Despite numerous reports on LSPR bionanosensing in the past, no study thus far has applied the technique for a cytokine secretion assay using clinically relevant immune cells from human blood. Cytokine secretion assays, a technique to quantify intercellular-signaling proteins secreted by blood immune cells, allow determination of the functional response of the donor's immune cells, thus providing valuable information about the immune status of the donor. However, implementation of LSPR bionanosensing in cellular functional immunoanalysis based on a cytokine secretion assay poses major challenges primarily owing to its limited sensitivity and a lack of sufficient sample handling capability. In this paper, we have developed a label-free LSPR biosensing technique to detect cell-secreted tumor necrosis factor (TNF)-α cytokines in clinical blood samples. Our approach integrates LSPR bionanosensors in an optofluidic platform that permits trapping and stimulation of target immune cells in a microfluidic chamber with optical access for subsequent cytokine detection. The on-chip spatial confinement of the cells is the key to rapidly increasing a cytokine concentration high enough for detection by the LSPR setup, thereby allowing the assay time and sample volume to be significantly reduced. We have successfully applied this approach first to THP-1 cells and then later to CD45 cells isolated directly from human blood. Our LSPR optofluidics device allows for detection of TNF-α secreted from cells as few as 1000, which translates into a nearly 100 times decrease in sample volume than conventional cytokine secretion assay techniques require. We achieved cellular functional immunoanalysis with a minimal blood sample volume (3 µL) and a total assay time 3 times shorter than that of the conventional enzyme-linked immunosorbent assay (ELISA).


Assuntos
Citocinas/sangue , Imunoensaio/métodos , Nanotecnologia/métodos , Ressonância de Plasmônio de Superfície/métodos , Calibragem , Desenho de Equipamento , Humanos , Imunoensaio/instrumentação , Técnicas Analíticas Microfluídicas , Nanotecnologia/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação
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