There is no single detection method used for Alzheimer's diagnostics. Physicians use multiple diagnostic tools to assess patients’ conditions and make a diagnosis. Factors such as blood pressure, pulse, medications used, or diet can be used for a primary assessment by the physician. Moreover, blood or/and urine samples can be taken for a laboratory test that can detect symptoms of dementia. Moreover, neurological and mental cognitive status tests are often performed to evaluate the memory, thinking, and simple problem-solving abilities of the patient as well as the patient's reflex, eye movement, coordination, etc. Mental health conditions such as depression are often associated with the disease.
Finally, different imaging modalities such as Computer Tomography (CT), Magnetic Resonance Imagining (IMR), and Positron Emission Tomography (PET) are used to analyze the structure of the brain and rule out conditions similar to Alzheimer's. These modalities can detect tumors, evidence of stroke, or a buildup of fluid in the brain (How Is Alzheimer’s Disease Diagnosed?, n.d.). Those tests can be repeated over time to measure how the patient’s condition changes over time. People with memory problems should get regularly tested each year.
While there is still no cure for Alzheimer's there are some medications that can prepare patients to better cope with syndromes of the disease. The medications are the most effective in the early and middle stages of the disease. Moreover, early diagnosis may help preserve daily functioning for some time and can help patients and their families prepare to deal with cognitive disorders later on.
One of the biggest challenges associated with early detection of Alzheimer’s is that changes in the brain start to accumulate as early as 10-15 years before cognitive dysfunctions such as dementia can be observed. Patients with very early stage of the disease may show no clinical signs of dementia however, they may experience mood changes, changes in social behavior, depressive episodes etc. The aim of early stage diagnostics is to detect first pathological processes underlying the disease which would therefore enable to modify or even slow down the progression of disease (Bogdanovic, 2018). One of such approaches includes detecting biomarkers present in an early stage disease such as Aβ species.
In 2019, there were over 703 million people aged 65 years and over. By 2050, this number is expected to double - it is predicted that there will be 1.5 billion people aged 65 years and over (United Nations). As high age is the most important known risk factor for Alzheimer's disease (NIH), the size of the population affected by this disease will continue to increase. The elderly population in the Middle East is predicted to rise in the next few decades with a fivefold or higher expected increment in the next in countries like the United Arab Emirates. As the country is undergoing the “Health Transition Phase”, its effect will significantly affect the healthcare system and related services (Abyad).
Our project is thus targeted primarily toward the aging population and particularly the elderly. The device we designed will be able to detect two important biomarkers of Alzheimer's disease: the tau and amyloid beta proteins from the blood samples.
We have designed a non-invasive and highly efficient device that uses aptamer-based technology. The use of aptamers has proven to be more beneficial than the use of antibodies, due to their higher stability, lower cost, and higher sensitivity.
Waste Disposal
The ultimate goal of the project is to design a non-reusable biochip that will detect Alzheimer’s disease using a small sample of blood. Furthemore, the needles used as sample collection method should be used only once.As a result, users will be provided with a recyclable biohazard bag within the toolkit in which they can store the used device and the blood collecting tool until they are able to responsibly dispose of it.
Purity of Sample
The purity of the sample could be easily compromised, especially since the biochip involves drawing blood from the patient. Given the nature of the device, the sample should be taken on the spot. To ensure maximum purity of the sample, it is vital to use a sterile needle to draw blood from the patient and avoid it touching any surface to avoid contamination of the sample. Furthermore, sterile conditions of the needle and the biochip are necessary to ensure the safety and good health of the patient.
Risk factors in sample collection
The samples collected consist of human blood, which is considered biohazardous waste. This is because it could potentially be infected with bloodborne pathogens or microorganisms, which could cause diseases to people in contact with it. Furthermore, blood collection involves the handling of sharp needles to puncture the patient’s body. As a result, it is of vital importance to ensure that the sharp object will be sterilized and used only once, to avoid the spread and infection of any bloodborne pathogen. Finally, the person handling the sharp object should exert extreme caution to avoid causing harm to themselves or others.
Inaccuracy of Testing
The peptide-specific aptamers used in this project have a high sensitivity to detecting and can detect AD-specific biomarkers in a wide dynamic range of concentrations. However, if the concentration of the sample is low and the aptamers do not bind to the peptides, the biochip could produce a false negative or inconclusive result.
Storage and Expiry of Diagnostic Device
The device can be utilized at room temperature, however, the biochip will have the best performance with a sample temperature of around 37° C (human body temperature). This is because usually, the detected biomarkers require specific physical and chemical conditions, such as temperature and pH to preserve a geometry specific to the aptamers immobilized in the biochip, thus ensuring accurate diagnosis. Furthermore, the contents within our diagnostic device may degrade over time and will not generate accurate results. This should be noted and expiry dates should be clearly stated.
