Optical glucose nanobiosensor encapsulated in erythrocytes

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on March 23, 2009)Vita.Thesis (Ph.D.) University of Missouri-Columbia 2007.An implantable glucose biosensor encapsulated in erythrocytes, Red Blood Cells (RBC), will become a method for continuously measuring blood glucose concentration in diabetics. In 2005, the American Diabetes Association (ADA) reported that 20.8 million people have diabetes, making it the fifth leading cause of death by disease in the USA. This paper focuses on the preparation phase of the glucose sensor. Glucose Binding Protein (GBP) from E. coli was labeled with two fluorophores, Alexa Fluor 680 (AF680), and Alexa Fluor 750 (AF750). This sensor based on Fluorescence Resonance Energy Transfer (FRET). FRET is a distance sensitive technique between the above fluorophores. The initial energy transfer between AF680 and AF750 labeled on the GBP before glucose additions was determined. After glucose additions, the labeled GBP went through conformational change which caused distance between the labeled sites. This change in distance caused a change in the energy transfer. The labeled GBP became the glucose nanobiosensor. The labeled GBP nanobiosensors were encapsulated in erythrocytes, red blood cells (RBCs), by using the Hypo-Osmotic dialysis technique. The encapsulated RBCs responded well to different glucose concentrations ranging form 0-33.16mM. This range covers the normal blood glucose concentration, 4 - 9mM.Includes bibliographical reference

Glucose Binding Protein as a Novel Optical Glucose Nanobiosensor

Development of an in vivo optical sensor requires the utilization of Near Infra Red (NIR) fluorophores due to their ability to operate within the biological tissue window. Alexa Fluor 750 (AF750) and Alexa Fluor 680 (AF680) were examined as potential NIR fluorophores for an in vivo fluorescence resonance energy transfer (FRET) glucose biosensor. AF680 and AF750 found to be a FRET pair and percent energy transfer was calculated. Next, the tested dye pair was utilized in a competitive binding assay in order to detect glucose. Concanavalin A (Con A) and dextran have binding affinity, but in the presence of glucose, glucose displaces dextran due to its higher affinity to Con A than dextran. Finally, the percent signal transfer through porcine skin was examined. The results showed with approximately 4.0 mm porcine skin thickness, 1.98 % of the fluorescence was transmitted and captured by the detector

NIR FRET Fluorophores for Use as an Implantable Glucose Biosensor

Development of an in vivo optical sensor requires the utilization of Near Infra Red (NIR) fluorophores due to their ability to operate within the biological tissue window. Alexa Fluor 750 (AF750) and Alexa Fluor 680 (AF680) were examined as potential NIR fluorophores for an in vivo fluorescence resonance energy transfer (FRET) glucose biosensor. AF680 and AF750 found to be a FRET pair and percent energy transfer was calculated. Next, the tested dye pair was utilized in a competitive binding assay in order to detect glucose. Concanavalin A (Con A) and dextran have binding affinity, but in the presence of glucose, glucose displaces dextran due to its higher affinity to Con A than dextran. Finally, the percent signal transfer through porcine skin was examined. The results showed with approximately 4.0 mm porcine skin thickness, 1.98 % of the fluorescence was transmitted and captured by the detector

A Review of SARS-CoV-2 Disease (COVID-19): Pandemic in Our Time

Development and deployment of biosensors for the rapid detection of the 2019 novel severe acute respiratory syndrome—coronavirus 2 (SARS-CoV-2) are of utmost importance and urgency during this recent outbreak of coronavirus pneumonia (COVID-19) caused by SARS-CoV-2 infection, which spread rapidly around the world. Cases now confirmed in February 2022 indicate that more than 170 countries worldwide are affected. Recent evidence indicates over 430 million confirmed cases with over 5.92 million deaths scattered across the globe, with the United States having more than 78 million confirmed cases and over 920,000 deaths. The US now has many more cases than in China where coronavirus cases were first reported in late December 2019. During the initial outbreak in China, many leaders did not anticipate it could reach the whole world, spreading to many countries and posing severe threats to global health. The objective of this review is to summarize the origin of COVID-19, its biological nature, comparison with other coronaviruses, symptoms, prevention, treatment, potential, available methods for SARS-CoV-2 detection, and post-COVID-19 symptoms

Efficient and Rapid Detection of Salmonella Using Microfluidic Impedance Based Sensing

We present a low cost, easy to fabricate biosensor, which can quickly and accurately detect Salmonella typhimurium. This study also compares the advantages of the microfluidic biosensor over a nonmicrofluidic biosensor. High density interdigitated electrode array was used to detect Salmonella cells inside a microfluidic chip. Monoclonal anti-Salmonella antibodies were allowed to be immobilized on the surface of the electrode array for selective detection of Salmonella typhimurium. An impedance analyzer was used to measure and record the response signal from the biosensor. The biosensor provides qualitative and quantitative results in 3 hours without any enrichment steps. The microfluidic biosensor’s lower detection limit was found to be 3×103 CFU/mL compared to the 3×104 CFU/mL of the nonmicrofluidic biosensor, which shows that the microfluidic biosensor has 10-fold increased sensitivity. The impedance response of microfluidic biosensor was also significantly higher (2 to 2.9 times) compared to the nonmicrofluidic biosensor