Heat shock protein 70 (HSP70) is an important health related biomarker, being implicated as an early stage cancer marker and as an indicator of cardiac health. It also has important implications in wildlife environmental monitoring, as its levels can be affected by food deprivation, elevated temperatures, and pollution. Therefore, the use of HSP70 as a biomarker is highly desirable, yet the current methods of quantifying HSP70 are time consuming, expensive, and require dedicated labs. In order to facilitate widespread use of the HSP70 biomarker, a quantification tool that can be used at the point-of-care is needed. This implies the development of a simple and inexpensive HSP70 biosensing technique that is highly sensitive and selective. Therefore, in this work a label-free HSP70 biosensor has been designed based on the optical properties of gold nanoparticles (NPs). Gold NPs exhibit a large absorbance peak in the visible spectrum due to localized surface plasmon resonance (LSPR). The peak position is dependent on the local refractive index, which can be employed as a biosensor by selectively capturing the target analyte to the NP surface. To design an LSPR HSP70 sensor, optical and fluidic simulations were developed to determine optimal NP geometries and microchannel dimensions. The results showed optimal response when using 100nmx5nm gold nanotriangles inside of a 100μmx100μm microchannel. Simulations of the sensor performance showed HSP70 detection from 0.92-4000ng/ml with a resolution of 1.1ng/ml, all of which satisfied the design requirements. An LSPR sensor was experimentally tested at the benchtop scale to prove the concept. Gold NPs were fabricated by electron beam lithography and enclosed in a polymer flow cell. For initial testing of the LSPR sensor, the NPs were functionalized with biotin for selective capture of streptavidin. Streptavidin was detected in real time over the range 55-500,000ng/ml. The use of bovine serum albumin (BSA) was shown to be necessary to block non-specific binding sites to ensure a streptavidin-specific response. The LSPR sensor was then demonstrated to detect salmon HSP70 at 4600ng/ml using its synthetic antibody. Overall, these results demonstrate that LSPR can be used to realize an HSP70 biosensor suitable for point-of-care applications.

Affinity-based biosensors, or in short biosensors, are extremely powerful and versatile analytical tools which are used for the detection of a wide variety of bio-molecules. In recent times, there has been a need for developing low-cost and portable affinity-based biosensor platforms. Such systems need to have a high density of detection sites (i.e biosensing elements) in order to simultaneously detect multiple analytes in a single sample. This has led to the creation of integrated biosensors, which make use of integrated circuits (ICs) for bio-molecular detection. In such systems, it has been demonstrated that by taking advantage of the capabilities of semiconductor and very large scale integrated (VLSI) circuit fabrication processes, it is possible to build compact miniaturized biosensors, which can be used in wide variety of applications such as in molecular diagnostics and for environmental monitoring. Among the various detection modalities for biosensors, Electrochemical Impedance Spectroscopy (EIS) permits real-time detection and has label-free detection capabilities. EIS is fully electronic in nature. Hence, it can be implemented using standard IC technologies. The versatility and ease of integration of EIS makes it a promising candidate for developing integrated biosensor platforms. In this thesis, we first examine the underlying principles of EIS method of biosensing. By analyzing an immunosensor assay as an example, we show that EIS based biosensing is a highly sensitive detection method, which can be used for the detection of a wide variety of analytes. Since EIS relies on small impedance changes in order to perform detection, it requires highly accurate models for the electrode-electrolyte systems. Hence, we also introduce a compact modeling technique for the distributed electrode-electrolyte systems with non-uniform electric fields, which is capable of modelling noise and other non-idealities in EIS. In the second part of this thesis, we describe the design and implementation of an integrated EIS biosensor array, built using a standard complementary metal-oxide-semiconductor (CMOS) process. The chip is capable of measuring admittance values as small as 10nS and has a wide dynamic range (90dB) over a wide range of frequencies (10Hz-50MHz). We also report the results obtained from the DNA and protein detection experiments performed using this chip. / text

Rapid diagnosis of infectious disease and timely initiation of proper clinical antibiotic treatment is the determinant in obtaining the optimal clinical outcomes and reducing emergences of multidrug-resistant organisms. In particular, acute infections require the detection to be accomplished in limited time with high sensitivity due to the low concentration of organisms causing the infections. Real-time Polymerase Chain Reaction can provide quantitative identification of specific genetic materials and has revolutionized clinical microbiology laboratory diagnosis. It is becoming a standard for infectious disease detection. However, most real-time PCR instruments on the market are bulky, fragile and costly due to their delicate optical components, which restricted their use to point-of-care application. Modern microfluidic and sensing technology provide a transition from benchtop real-time PCR to miniaturizable, robust, and portable real-time PCR devices to achieve rapid, low-cost, and efficient point-of-care diagnosis. In this work, an innovative electrokinetic PCR (EK-PCR) platform that combines AC electrothermal flow (ACEF) and Joule heating induced temperature gradient to implement thermal cycling for DNA amplification is discussed. In addition, in situ electrochemical sensing is incorporated in the EK-PCR chamber for real-time monitoring of the DNA concentration toward quantification of the initial copies of the DNA template. EK-PCR can improve the energy efficiency with minimized total thermal mass and remain high amplification efficiency. More importantly, it represents a highly integrated strategy for portable point-of-care devices.

Heat shock protein 70 (HSP70) is an important health related biomarker, being implicated as an early stage cancer marker and as an indicator of cardiac health. It also has important implications in wildlife environmental monitoring, as its levels can be affected by food deprivation, elevated temperatures, and pollution. Therefore, the use of HSP70 as a biomarker is highly desirable, yet the current methods of quantifying HSP70 are time consuming, expensive, and require dedicated labs. In order to facilitate widespread use of the HSP70 biomarker, a quantification tool that can be used at the point-of-care is needed. This implies the development of a simple and inexpensive HSP70 biosensing technique that is highly sensitive and selective. Therefore, in this work a label-free HSP70 biosensor has been designed based on the optical properties of gold nanoparticles (NPs). Gold NPs exhibit a large absorbance peak in the visible spectrum due to localized surface plasmon resonance (LSPR). The peak position is dependent on the local refractive index, which can be employed as a biosensor by selectively capturing the target analyte to the NP surface. To design an LSPR HSP70 sensor, optical and fluidic simulations were developed to determine optimal NP geometries and microchannel dimensions. The results showed optimal response when using 100nmx5nm gold nanotriangles inside of a 100μmx100μm microchannel. Simulations of the sensor performance showed HSP70 detection from 0.92-4000ng/ml with a resolution of 1.1ng/ml, all of which satisfied the design requirements. An LSPR sensor was experimentally tested at the benchtop scale to prove the concept. Gold NPs were fabricated by electron beam lithography and enclosed in a polymer flow cell. For initial testing of the LSPR sensor, the NPs were functionalized with biotin for selective capture of streptavidin. Streptavidin was detected in real time over the range 55-500,000ng/ml. The use of bovine serum albumin (BSA) was shown to be necessary to block non-specific binding sites to ensure a streptavidin-specific response. The LSPR sensor was then demonstrated to detect salmon HSP70 at 4600ng/ml using its synthetic antibody. Overall, these results demonstrate that LSPR can be used to realize an HSP70 biosensor suitable for point-of-care applications.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The key research question examined in this thesis was: Could POCT ( point-of-care pathology testing) models that were analytically sound and clinically and culturally effective be established in Australian Indigenous medical services for the prevention and management of diabetes and renal disease? The systematic approach to answer this overarching research question included the scientific validation of the analytical performance of suitable point-of-care (POC) devices, the development of a culturally appropriate education and training program for Aboriginal Health Workers (and nurses) as POCT operators, the implementation of a quality management framework for maintaining surveillance of the analytical quality of POCT results, and an assessment of qualitative and quantitative research outcomes to determine the clinical and cultural effectiveness of POCT. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277656 / Thesis (Ph.D.) -- University of Adelaide, School of Population Health and Clinical Practice, 2007

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The key research question examined in this thesis was: Could POCT ( point-of-care pathology testing) models that were analytically sound and clinically and culturally effective be established in Australian Indigenous medical services for the prevention and management of diabetes and renal disease? The systematic approach to answer this overarching research question included the scientific validation of the analytical performance of suitable point-of-care (POC) devices, the development of a culturally appropriate education and training program for Aboriginal Health Workers (and nurses) as POCT operators, the implementation of a quality management framework for maintaining surveillance of the analytical quality of POCT results, and an assessment of qualitative and quantitative research outcomes to determine the clinical and cultural effectiveness of POCT. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277656 / Thesis (Ph.D.) -- University of Adelaide, School of Population Health and Clinical Practice, 2007

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The key research question examined in this thesis was: Could POCT ( point-of-care pathology testing) models that were analytically sound and clinically and culturally effective be established in Australian Indigenous medical services for the prevention and management of diabetes and renal disease? The systematic approach to answer this overarching research question included the scientific validation of the analytical performance of suitable point-of-care (POC) devices, the development of a culturally appropriate education and training program for Aboriginal Health Workers (and nurses) as POCT operators, the implementation of a quality management framework for maintaining surveillance of the analytical quality of POCT results, and an assessment of qualitative and quantitative research outcomes to determine the clinical and cultural effectiveness of POCT. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277656 / Thesis (Ph.D.) -- University of Adelaide, School of Population Health and Clinical Practice, 2007

Protein biomarkers are important diagnostic tools for detection of non-communicable diseases, such as cancer and cardiovascular conditions. In order to be used as diagnostic tools they need to be detected at very low concentrations in biological samples (e.g. whole blood, serum or urine). This has been currently performed in central laboratories using expensive, bulky equipment and time consuming assays.

Globally, the microbe Neisseria gonorrhoeae (NG) causes 106 million newly documented sexually transmitted infections each year. Once appropriately diagnosed, NG infections can be treated with readily available antibiotics, but patients in low-resource settings often do not return to the clinic for results. As current NG diagnostic gold standards suffer from slow turnaround time to result, a rapid, sensitive molecular diagnostic would help increase appropriate treatment at the point-of-care. Here, we report on the design and development of a minimally-instrumented paper-fluidic POC diagnostic that incorporates patient swab sample lysis, isothermal nucleic acid capture, thermophilic helicase-dependent amplification (tHDA), an internal amplification control (NGIC), and lateral flow visual detection. Limits of NG detection for the NG/NGIC multiplex tHDA assay were determined within the device, and device clinical performance was validated retroactively against qPCR-quantified patient samples in a proof-of-concept sensitivity and specificity study. This proof-of-principle paper-fluidic diagnostic, which can be completed within 80 minutes, selectively amplifies and detects NG in multiplex with NGIC. It has a clinically relevant limit of detection of 1000 NG cells per device. In urethral swab sample trials (N=20), the device approaches current gold standard NG diagnostic capabilities with 90% sensitivity and 100% specificity and vaginal swab sample trials (N=20) surpass the gold standard with 100% sensitivity and 100% specificity.

Background: Acute heart failure and chronic obstructive pulmonary disease (COPD) exacerbation are common, and are sometimes difficult to differentiate in the emergency department (ED). Objectives: To determine the clinical impact of Point-of-Care Ultrasonography (POCUS) in ED patients with suspected acute heart failure or COPD. Methods: We conducted a prospective health records review with 1:3 matching, and analyzed time to events using time-dependent Cox regression analyses, classification performance, and adverse events. Results: There were 81 patients with lung POCUS and 243 matched patients. No differences were found in ED length of stay or length of care, nor adverse events. Significance was found for time to treatment (P=0.03). Lung POCUS had high sensitivity (92.5%) and specificity (85.7%) for identifying acute heart failure. Conclusions: Lung POCUS could result in faster treatments for patients with suspected acute heart failure and COPD, and has high accuracy in identifying acute heart failure.