Displaying publications 1 - 20 of 72 in total

Abstract:
Sort:
  1. James V, Samuel J, Kee CY, Ong GY
    Ultrasound J, 2020 Dec 03;12(1):51.
    PMID: 33270182 DOI: 10.1186/s13089-020-00199-y
    BACKGROUND: The presence of intra-abdominal calcification in the pediatric population can be due to a wide range of conditions. Calcification in the abdomen can be seen in normal or abnormal anatomical structures. In some patients, abnormal calcification points towards the pathology; whereas in others, calcification itself is the pathology. After a thorough history and clinical examination, point-of-care ultrasound (POCUS) would complement the assessment of acute abdominal pain, based on the list of differentials generated as per the abdominal region. The main objective of this article is to review commonly encountered causes of intra-abdominal calcifications in the pediatric population and help in clinical decision-making in a Pediatric Emergency Department.

    CASE PRESENTATION: We describe a series of pediatric patients who presented to the Pediatric Emergency Department with acute abdominal pain, in whom point-of-care ultrasound helped expedite the diagnosis by identifying varying types of calcification and associated sonological findings. For children who present to the Pediatric Emergency Department with significant abdominal pain, a rapid distinction between emergencies and non-emergencies is vital to decrease morbidity and mortality.

    CONCLUSIONS: In a child presenting to the Pediatric Emergency Department with abdominal pain, POCUS and the findings of calcifications can narrow or expand the differential diagnosis when integrated with history and physical exam, to a specific anatomic structure. Integrating these findings with additional sonological findings of an underlying pathology might raise sufficient concerns in the emergency physicians to warrant further investigations for the patient in the form of a formal radiological ultrasound and assist in the patient's early disposition. The use of POCUS might also help to categorize the type of calcification to one of the four main categories of intra-abdominal calcifications, namely concretions, conduit wall calcification, cyst wall calcification, and solid mass-type calcification. POCUS used thoughtfully can give a diagnosis and expand differential diagnosis, reduce cognitive bias, and reduce physician mental load. By integrating the use of POCUS with the history and clinical findings, it will be possible to expedite the management in children who present to the Pediatric Emergency Department with acute abdominal pain.

    Matched MeSH terms: Point-of-Care Systems
  2. Adi O, Fong CP, Azil A, Wahab SFA
    Ultrasound J, 2019 Feb 25;11(1):1.
    PMID: 31359296 DOI: 10.1186/s13089-019-0116-9
    BACKGROUND: We report a case study of fat embolism seen on ultrasound at right internal jugular vein during central venous cannulation in a patient diagnosed with fat embolism syndrome. This case demonstrates the importance of ultrasound for evaluation of trauma cases with suspicion of fat embolism.

    CASE PRESENTATION: A 23-year-old trauma patient with closed fracture of left femoral shaft and left humerus presented to our emergency department (ED). 11 h after admission to ED, patient became confused, hypoxic and hypotensive. He was then intubated for respiratory failure and mechanically ventilated. Transesophageal ultrasound revealed hyperdynamic heart, dilated right ventricle with no regional wall abnormalities and no major aorta injuries. Whole-body computed tomography was normal. During central venous cannulation of right internal jugular vein (IJV), we found free floating mobile hyperechoic spots, located at the anterior part of the vein. A diagnosis of fat embolism syndrome later was made based on the clinical presentation of long bone fractures and fat globulin in the blood. Despite aggressive fluid resuscitation, patient was a non-responder and needed vasopressor infusion for persistent shock. Blood aspirated during cannulation from the IJV revealed a fat globule. Patient underwent uneventful orthopedic procedures and was discharged well on day 5 of admission.

    CONCLUSIONS: Point-of-care ultrasound findings of fat embolism in central vein can facilitate and increase the suspicion of fat embolism syndrome.

    Matched MeSH terms: Point-of-Care Systems
  3. James V, Kee CY, Ong GY
    J Emerg Med, 2019 Apr;56(4):421-425.
    PMID: 30638645 DOI: 10.1016/j.jemermed.2018.12.015
    BACKGROUND: Point-of-care ultrasonography (POCUS) is increasingly used for both diagnostic and guided procedures. Increasingly, POCUS has been used for identification of pneumonia and to assist in the differentiation of pleural effusions, as well as to guide thoracentesis. As such, there is a need for training with ideally high-fidelity lung ultrasound phantoms to ensure ultrasound proficiency and procedural competency. Unfortunately, most commercial ultrasound phantoms remain expensive and may have limited fidelity.

    OBJECTIVE: Our aim was to create and describe a homemade, high-fidelity ultrasound phantom model for demonstrating pneumonia with pleural effusions for teaching purposes.

    DISCUSSION: An ultrasound phantom was constructed using a water-filled latex glove with a sliver of meat in it, covered over by a palm-sized piece of meat (skin and ribs are optional to increase ultrasonographic details and realism). This would appear like parapneumonic effusions with organized pneumonia under ultrasound examination. Creamer (or talc) can be added to the water in the glove to simulate empyema. The model can also be used to teach simple effusions and for ultrasound-guided thoracentesis and in clinical decision making.

    CONCLUSIONS: Easily prepared, homemade high-fidelity ultrasound phantom models for instructions on identification of pleural effusions and ultrasound-guided pleural tap of parapneumonic effusion were made.

    Matched MeSH terms: Point-of-Care Systems
  4. Osman A, Fong CP, Wahab SFA, Panebianco N, Teran F
    J Emerg Med, 2020 Sep;59(3):418-423.
    PMID: 32591302 DOI: 10.1016/j.jemermed.2020.05.003
    BACKGROUND: Although surface sonography has become an essential diagnostic tool in the evaluation of trauma patients, important limitations of this modality include the evaluation of retroperitoneal hemorrhage and mediastinal pathology, such as blunt traumatic aortic injuries (BTAI). As in other emergency applications where surface sonography can't provide the information needed, focused transesophageal echocardiography (TEE) may represent a valuable diagnostic tool in the evaluation of hemodynamically unstable trauma patients with suspected thoracic pathology such as BTAI.

    CASE SERIES: We present a series of five cases that illustrate the diagnostic value of emergency physician-performed resuscitative TEE in the diagnosis of BTAI in patients presenting with blunt thoracic trauma. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: As the use of point-of-care TEE during resuscitation continues to expand in emergency medicine, the evaluation of patients with BTAI represents a novel application where this emerging modality can allow early diagnosis of these injuries in hemodynamically unstable patients.

    Matched MeSH terms: Point-of-Care Systems
  5. Balakrishnan P, Saravanan S, Vignesh R, Shankar EM
    Indian J Med Res, 2023 Nov 01;158(5&6):447-450.
    PMID: 38063301 DOI: 10.4103/ijmr.ijmr_1616_23
    Matched MeSH terms: Point-of-Care Systems*
  6. Choi JR, Hu J, Gong Y, Feng S, Wan Abas WA, Pingguan-Murphy B, et al.
    Analyst, 2016 05 10;141(10):2930-9.
    PMID: 27010033 DOI: 10.1039/c5an02532j
    Lateral flow assays (LFAs) have been extensively explored in nucleic acid testing (NAT) for medical diagnostics, food safety analysis and environmental monitoring. However, the amount of target nucleic acid in a raw sample is usually too low to be directly detected by LFAs, necessitating the process of amplification. Even though cost-effective paper-based amplification techniques have been introduced, they have always been separately performed from LFAs, hence increasing the risk of reagent loss and cross-contaminations. To date, integrating paper-based nucleic acid amplification into colorimetric LFA in a simple, portable and cost-effective manner has not been introduced. Herein, we developed an integrated LFA with the aid of a specially designed handheld battery-powered system for effective amplification and detection of targets in resource-poor settings. Interestingly, using the integrated paper-based loop-mediated isothermal amplification (LAMP)-LFA, we successfully performed highly sensitive and specific target detection, achieving a detection limit of as low as 3 × 10(3) copies of target DNA, which is comparable to the conventional tube-based LAMP-LFA in an unintegrated format. The device may serve in conjunction with a simple paper-based sample preparation to create a fully integrated paper-based sample-to-answer diagnostic device for point-of-care testing (POCT) in the near future.
    Matched MeSH terms: Point-of-Care Systems
  7. Britton S, Cheng Q, Grigg MJ, William T, Anstey NM, McCarthy JS
    Am J Trop Med Hyg, 2016 07 06;95(1):120-2.
    PMID: 27162264 DOI: 10.4269/ajtmh.15-0670
    The simian parasite Plasmodium knowlesi is now the commonest cause of malaria in Malaysia and can rapidly cause severe and fatal malaria. However, microscopic misdiagnosis of Plasmodium species is common, rapid antigen detection tests remain insufficiently sensitive and confirmation of P. knowlesi requires polymerase chain reaction (PCR). Thus available point-of-care diagnostic tests are inadequate. This study reports the development of a simple, sensitive, colorimetric, high-throughput loop-mediated isothermal amplification assay (HtLAMP) diagnostic test using novel primers for the detection of P. knowlesi. This assay is able to detect 0.2 parasites/μL, and compared with PCR has a sensitivity of 96% for the detection of P. knowlesi, making it a potentially field-applicable point-of-care diagnostic tool.
    Matched MeSH terms: Point-of-Care Systems
  8. Adi O, Fong CP, Sum KM, Ahmad AH
    Am J Emerg Med, 2021 04;42:263.e1-263.e4.
    PMID: 32994082 DOI: 10.1016/j.ajem.2020.09.011
    Airway assessment is important in emergency airway management. A difficult airway can lead to life-threatening complications. A perfect airway assessment tool does not exist and unanticipated difficulty will remain unforeseen. Current bedside clinical predictors of the difficult airway are unreliable but airway ultrasound can be used as an adjunct to predict difficult laryngoscopy. We report a case of a 60-year-old man presenting to the emergency department with shortness of breath, hoarseness of voice and stridor. Airway ultrasound revealed a large laryngeal mass narrowing the upper airway, extending to bilateral vocal cords with heterogenous echogenicity. In view of impending complete upper airway obstruction, acute respiratory distress and airway ultrasound findings, urgent emergency tracheostomy was chosen as definitive airway over endotracheal intubation or surgical cricothyroidotomy. Point of care ultrasound (POCUS) was used to evaluate this patient with severe upper airway obstruction. A laryngeal mass was detected by ultrasound and this pointed towards the presence of a difficult airway. POCUS was a good non-invasive tool used for airway assessment in this uncooperative and unstable patient. Ultrasound predictors of the difficult airway include the inability to visualize the hyoid bone, short hyomental distance ratio, high pretracheal anterior neck thickness and large tongue size. Besides airway assessment, ultrasound can also help to predict endotracheal tube size, confirm intubation and guide emergency airway procedures such as cricothyroidotomy and tracheostomy. Point of care ultrasound of the upper airway can be used in airway assessment to identify distorted airway anatomy, pathological lesions and guide treatment decisions.
    Matched MeSH terms: Point-of-Care Systems*
  9. Citartan M, Tang TH
    Talanta, 2019 Jul 01;199:556-566.
    PMID: 30952298 DOI: 10.1016/j.talanta.2019.02.066
    Aptamers are nucleic acid-based molecular recognition elements that are specific and have high binding affinity against their respective targets. On account of their target recognition capacity, aptamers are widely utilized in a number of applications including diagnostics. This review aims to highlight the recent developments of aptasensors expedient for point-of-care (POC) diagnostics. Significant focus is given on the primary assay formats of aptamers such as fluorescence, electrochemical, surface plasmon resonance (SPR) and colorimetric assays. A potpourri of platforms such as paper-based device, lateral flow assay, portable electrodes, portable SPR and smart phones expedient for point-of-care (POC) diagnostics are discussed. Emphasis is also given on the technicalities and assay configurations associated with the sensors.
    Matched MeSH terms: Point-of-Care Systems*
  10. Citartan M
    Talanta, 2021 Sep 01;232:122436.
    PMID: 34074421 DOI: 10.1016/j.talanta.2021.122436
    Dot blot assays have always been associated with antibodies as the main molecular recognition element, which are widely employed in a myriad of diagnostic applications. With the rising of aptamers as the equivalent molecular recognition elements of antibodies, dot blot assays are also one of the diagnostic avenues that should be scrutinized for their amenability with aptamers as the potential surrogates of antibodies. In this review, the stepwise procedures of an aptamer-based dot blot assays are underscored before reviewing the existing aptamer-based dot blot assays developed so far. Most of the applications center on monitoring the progress of SELEX and as the validatory assays to assess the potency of aptamer candidates. For the purpose of diagnostics, the current effort is still languid and as such possible suggestions to galvanize the move to spur the aptamer-based dot blot assays to a point-of-care arena are discussed.
    Matched MeSH terms: Point-of-Care Systems
  11. Hu J, Yew CT, Chen X, Feng S, Yang Q, Wang S, et al.
    Talanta, 2017 Apr 01;165:419-428.
    PMID: 28153277 DOI: 10.1016/j.talanta.2016.12.086
    The identification and quantification of chemicals play a vital role in evaluation and surveillance of environmental health and safety. However, current techniques usually depend on costly equipment, professional staff, and/or essential infrastructure, limiting their accessibility. In this work, we develop paper-based capacitive sensors (PCSs) that allow simple, rapid identification and quantification of various chemicals from microliter size samples with the aid of a handheld multimeter. PCSs are low-cost parallel-plate capacitors (~$0.01 per sensor) assembled from layers of aluminum foil and filter paper via double-sided tape. The developed PCSs can identify different kinds of fluids (e.g., organic chemicals) and quantify diverse concentrations of substances (e.g., heavy metal ions) based on differences in dielectric properties, including capacitance, frequency spectrum, and dielectric loss tangent. The PCS-based method enables chemical identification and quantification to take place much cheaply, simply, and quickly at the point-of-care (POC), holding great promise for environmental monitoring in resource-limited settings.
    Matched MeSH terms: Point-of-Care Systems
  12. Iqhbal M, Noor JM, Karim NA, Ismail I, Sanib H, Mokhtar MA, et al.
    Sultan Qaboos Univ Med J, 2018 May;18(2):e219-e222.
    PMID: 30210855 DOI: 10.18295/squmj.2018.18.02.017
    The use of ultrasonography in acute and critical care medicine is becoming increasingly common. However, use of an airway ultrasound as an adjunct to determine the type of intervention needed and assess complications is not common practice. We report a 56-year-old male who presented to the Emergency Department of the Sungai Buloh Hospital, Selangor, Malaysia, in 2015 with hoarseness, stridor and impending respiratory failure. A point-of-care ultrasound performed to assess the neck and vocal cords indicated a heterogeneous echogenic mass in the larynx, thus ruling out a cricothyroidotomy. The patient was therefore referred for an emergency tracheostomy. This case highlights the importance of point-of-care airway ultrasonography in the assessment of patients with stridor. This imaging technique not only helps to detect the cause of the stridor, but also to determine the feasibility of a cricothyroidotomy in emergency cases.
    Matched MeSH terms: Point-of-Care Systems*
  13. Thiha A, Ibrahim F
    Sensors (Basel), 2015;15(5):11431-41.
    PMID: 25993517 DOI: 10.3390/s150511431
    The enzyme-linked Immunosorbent Assay (ELISA) is the gold standard clinical diagnostic tool for the detection and quantification of protein biomarkers. However, conventional ELISA tests have drawbacks in their requirement of time, expensive equipment and expertise for operation. Hence, for the purpose of rapid, high throughput screening and point-of-care diagnosis, researchers are miniaturizing sandwich ELISA procedures on Lab-on-a-Chip and Lab-on-Compact Disc (LOCD) platforms. This paper presents a novel integrated device to detect and interpret the ELISA test results on a LOCD platform. The system applies absorption spectrophotometry to measure the absorbance (optical density) of the sample using a monochromatic light source and optical sensor. The device performs automated analysis of the results and presents absorbance values and diagnostic test results via a graphical display or via Bluetooth to a smartphone platform which also acts as controller of the device. The efficacy of the device was evaluated by performing dengue antibody IgG ELISA on 64 hospitalized patients suspected of dengue. The results demonstrate high accuracy of the device, with 95% sensitivity and 100% specificity in detection when compared with gold standard commercial ELISA microplate readers. This sensor platform represents a significant step towards establishing ELISA as a rapid, inexpensive and automatic testing method for the purpose of point-of-care-testing (POCT) in resource-limited settings.
    Matched MeSH terms: Point-of-Care Systems*
  14. Yap BK, M Soair SN, Talik NA, Lim WF, Mei I L
    Sensors (Basel), 2018 Aug 10;18(8).
    PMID: 30103424 DOI: 10.3390/s18082625
    Over the past 20 years, rapid technological advancement in the field of microfluidics has produced a wide array of microfluidic point-of-care (POC) diagnostic devices for the healthcare industry. However, potential microfluidic applications in the field of nutrition, specifically to diagnose iron deficiency anemia (IDA) detection, remain scarce. Iron deficiency anemia is the most common form of anemia, which affects billions of people globally, especially the elderly, women, and children. This review comprehensively analyzes the current diagnosis technologies that address anemia-related IDA-POC microfluidic devices in the future. This review briefly highlights various microfluidics devices that have the potential to detect IDA and discusses some commercially available devices for blood plasma separation mechanisms. Reagent deposition and integration into microfluidic devices are also explored. Finally, we discuss the challenges of insights into potential portable microfluidic systems, especially for remote IDA detection.
    Matched MeSH terms: Point-of-Care Systems*
  15. Zainol Abidin AS, Rahim RA, Md Arshad MK, Fatin Nabilah MF, Voon CH, Tang TH, et al.
    Sensors (Basel), 2017 May 22;17(5).
    PMID: 28531146 DOI: 10.3390/s17051180
    Anxiety is a psychological problem that often emerges during the normal course of human life. The detection of anxiety often involves a physical exam and a self-reporting questionnaire. However, these approaches have limitations, as the data might lack reliability and consistency upon application to the same population over time. Furthermore, there might be varying understanding and interpretations of the particular question by the participant, which necessitating the approach of using biomarker-based measurement for stress diagnosis. The most prominent biomarker related to stress, hormone cortisol, plays a key role in the fight-or-flight situation, alters the immune response, and suppresses the digestive and the reproductive systems. We have taken the endeavour to review the available aptamer-based biosensor (aptasensor) for cortisol detection. The potential point-of-care diagnostic strategies that could be harnessed for the aptasensing of cortisol were also envisaged.
    Matched MeSH terms: Point-of-Care Systems*
  16. Ismail NF, Lim TS
    Sci Rep, 2016 Jan 19;6:19338.
    PMID: 26782912 DOI: 10.1038/srep19338
    Antibody labelling to reporter molecules is gaining popularity due to its many potential applications for diagnostics and therapeutics. However, non-directional bioconjugation methods which are commonly used often results in the loss of target binding capabilities. Therefore, a site-specific enzymatic based bioconjugation such as sortase-mediated transpeptidation allows for a more rapid and efficient method of antibody conjugation for diagnostic applications. Here we describe the utilization of sortase A bioconjugation to conjugate a single chain fragment variable (scFv) to the extracellular invertase (invB) from Zymomonas mobilis with the aim of developing an invertase based immunoassay. In addition, conjugation to enhanced green fluorescent protein (eGFP) was also validated to show the flexibility of the method. The invertase conjugated complex was successfully applied for the detection of antibody-antigen interaction using a personal glucose meter (PGM) for assay readout. The setup was used in both a direct and competitive assay highlighting the robustness of the conjugate for assay development. The method provides an alternative conjugation process to allow easy exchange of antibodies to facilitate rapid development of diagnostic assays for various diseases on the PGM platform.
    Matched MeSH terms: Point-of-Care Systems
  17. Tan MK, Siddiqi A, Yeo LY
    Sci Rep, 2017 07 27;7(1):6652.
    PMID: 28751783 DOI: 10.1038/s41598-017-07025-x
    The Miniaturised Lab-on-a-Disc (miniLOAD) platform, which utilises surface acoustic waves (SAWs) to drive the rotation of thin millimeter-scale discs on which microchannels can be fabricated and hence microfluidic operations can be performed, offers the possibility of miniaturising its larger counterpart, the Lab-on-a-CD, for true portability in point-of-care applications. A significant limitation of the original miniLOAD concept, however, is that it does not allow for flexible control over the disc rotation direction and speed without manual adjustment of the disc's position, or the use of multiple devices to alter the SAW frequency. In this work, we demonstrate the possibility of achieving such control with the use of tapered interdigitated transducers to confine a SAW beam such that the localised acoustic streaming it generates imparts a force, through hydrodynamic shear, at a specific location on the disc. Varying the torque that arises as a consequence by altering the input frequency to the transducers then allows the rotational velocity and direction of the disc to be controlled with ease. We derive a simple predictive model to illustrate the principle by which this occurs, which we find agrees well with the experimental measurements.
    Matched MeSH terms: Point-of-Care Systems
  18. Tan AF, Thota P, Sakam SSB, Lew YL, Rajahram GS, William T, et al.
    Sci Rep, 2023 Mar 23;13(1):4760.
    PMID: 36959462 DOI: 10.1038/s41598-023-31839-7
    Plasmodium knowlesi is the major cause of zoonotic malaria in Southeast Asia. Rapid and accurate diagnosis enables effective clinical management. A novel malaria diagnostic tool, Gazelle (Hemex Health, USA) detects haemozoin, a by-product of haem metabolism found in all Plasmodium infections. A pilot phase refined the Gazelle haemozoin identification algorithm, with the algorithm then tested against reference PCR in a larger cohort of patients with P. knowlesi mono-infections and febrile malaria-negative controls. Limit-of-detection analysis was conducted on a subset of P. knowlesi samples serially diluted with non-infected whole blood. The pilot phase of 40 P. knowlesi samples demonstrated 92.5% test sensitivity. P. knowlesi-infected patients (n = 203) and febrile controls (n = 44) were subsequently enrolled. Sensitivity and specificity of the Gazelle against reference PCR were 94.6% (95% CI 90.5-97.3%) and 100% (95% CI 92.0-100%) respectively. Positive and negative predictive values were 100% and 98.8%, respectively. In those tested before antimalarial treatment (n = 143), test sensitivity was 96.5% (95% CI 92.0-98.9%). Sensitivity for samples with ≤ 200 parasites/µL (n = 26) was 84.6% (95% CI 65.1-95.6%), with the lowest parasitaemia detected at 18/µL. Limit-of-detection (n = 20) was 33 parasites/µL (95% CI 16-65%). The Gazelle device has the potential for rapid, sensitive detection of P. knowlesi infections in endemic areas.
    Matched MeSH terms: Point-of-Care Systems
  19. Kho SS, Chan SK, Yong MC, Cheah HM, Lee YG, Tie ST
    Respir Investig, 2020 Sep;58(5):367-375.
    PMID: 32107195 DOI: 10.1016/j.resinv.2020.01.004
    BACKGROUND: Tuberculous pleural effusions (TBEs) and parapneumonic pleural effusion (PPEs) have similar clinical presentations and fluid biochemistry. A pleural biopsy is usually required to diagnose TBE but complete fluid evacuation may not be necessary, contrasting with complicated PPE (CPPE). A point-of-care test that distinguishes between TBE and CPPE enables the appropriate procedures to be performed during the initial diagnostic thoracentesis. Lactate is a metabolic product measurable by a blood-gas analyzer. This study measured pleural fluid (Pf) lactate levels in TBE and compared them with those in PPE/CPPE. We hypothesized that Pf lactate would be significantly higher in PPE because of active metabolic activities than in TBE which is driven by delayed hypersensitivity.

    METHODS: All patients undergoing an initial diagnostic thoracentesis over 18 months with Pf lactate measured using a calibrated point-of-care blood gas analyzer were assessed.

    RESULTS: The diagnoses of the enrolled patients (n = 170) included TBE (n = 49), PPE (n = 47), malignancy (n = 63), and transudate (n = 11). Pf lactate level in TBE, median 3.70 (inter-quartile range 2.65-4.90) mmol/l, was significantly lower than in PPE and CPPE. In the subgroup of TBE and CPPE patients whose initial Pf pH and glucose could suggest either condition, Pf lactate was significantly higher in those with CPPE. Pf lactate (cutoff ≥7.25 mmol/l) had a sensitivity of 79.3%, specificity 100%, positive predictive value 100%, and negative predictive value 89.1% for discriminating CPPE from TBE (area under the curve 0.947, p Point-of-care Pf lactate measurements may have practical value in early separation of TBE or CPPE during initial thoracentesis, and warrants further investigation.

    Matched MeSH terms: Point-of-Care Systems*
  20. Balakrishnan SR, Hashim U, Gopinath SC, Poopalan P, Ramayya HR, Iqbal Omar M, et al.
    PLoS One, 2015;10(9):e0137891.
    PMID: 26368287 DOI: 10.1371/journal.pone.0137891
    Human chorionic gonadotropin (hCG), a glycoprotein hormone secreted from the placenta, is a key molecule that indicates pregnancy. Here, we have designed a cost-effective, label-free, in situ point-of-care (POC) immunosensor to estimate hCG using a cuneated 25 nm polysilicon nanogap electrode. A tiny chip with the dimensions of 20.5 × 12.5 mm was fabricated using conventional lithography and size expansion techniques. Furthermore, the sensing surface was functionalized by (3-aminopropyl)triethoxysilane and quantitatively measured the variations in hCG levels from clinically obtained human urine samples. The dielectric properties of the present sensor are shown with a capacitance above 40 nF for samples from pregnant women; it was lower with samples from non-pregnant women. Furthermore, it has been proven that our sensor has a wide linear range of detection, as a sensitivity of 835.88 μA mIU(-1) ml(-2) cm(-2) was attained, and the detection limit was 0.28 mIU/ml (27.78 pg/ml). The dissociation constant Kd of the specific antigen binding to the anti-hCG was calculated as 2.23 ± 0.66 mIU, and the maximum number of binding sites per antigen was Bmax = 22.54 ± 1.46 mIU. The sensing system shown here, with a narrow nanogap, is suitable for high-throughput POC diagnosis, and a single injection can obtain triplicate data or parallel analyses of different targets.
    Matched MeSH terms: Point-of-Care Systems*
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links