Proteomics, Genomics & Microarrays
Single-molecule detections at point-of-care: is this a dream? Professor Luisa Torsi, Università degli Studi di Bari A. Moro,
luisa.torsi@
uniba.it
A healthcare system that addresses the healthy ones, is a visionary concept aiming to establish a proactive healthcare system that benefi ts all living beings on Earth. The core idea involves early identifi cation of asymptomatic individuals upon the onset of illness, enabling clinicians to intervene swiftly and effectively. This proactive approach contrasts with the current reactive model, where treatment primarily begins after symptoms appear, leading to a more effi cient and cost-effective system.
The key to this approach lies in identifying specifi c biomolecules, such as proteins, nucleic acids which serve as markers. These are measurable indicators that signal the presence or severity of a disease. They can be detected in various bodily fl uids like saliva, mucus, serum, plasma, and urine, providing early diagnostic capabilities.
Among biomarkers, molecular biomarkers, including oligonucleotide-based strands (DNA, RNA, mRNA) and proteins/antigens, are commonly utilised. These molecules selectively bind to specifi c probes or antibodies, enabling their detection with high sensitivity.
Biomarkers serve multiple purposes, including identifying asymptomatic individuals, characterising the different stages of disease progression with precision, and serving as targets in clinical trials. They are crucial not only in detecting tumoral conditions but also in diagnosing neurological pathologies, viral, or bacterial infections.
By leveraging biomarkers and advanced detection methods this approach to healthcare seeks to revolutionise its management, promising to enhance population well-being. Embracing this proactive paradigm shift holds the potential to transform our current reactive sick-care system into a proactive healthcare system, benefi ting all living species on our planet.
Cancer diagnosis traditionally relies on invasive tissue biopsies, yet liquid biopsies offer signifi cant advancements by detecting markers in blood sample in a minimally invasive, cost-effective, and allow continuous monitoring of tumour evolution and treatment response. However, biomarker concentrations in peripheral fl uids are much lower than in tumour masses, posing a challenge.
The possibility to combine ultra-portable, handheld, technologies for point-of-care testing (POCT), emphasising single-molecule detection capabilities with diagnostic sensitivity and selectivity above 95%, would be a dream come through and an extremely useful tool for reliable screening of asymptomatic individuals. Technologies like Single-Molecule-with-a-large-Transistor (SiMoT) (E. Genco, at al. Adv. Mater. 2023, 35, 2304102) and Clustered-Regularly-Interspaced-Short-Palindromic-Repeats (CRISPR) (R. Zhu et al. Anal. Chim. Acta 2023, 1257, 341175) offer multiplexing capabilities, detecting various diseases by altering recognition elements. CRISPR targets oligonucleotide biomarkers, while SiMoT detects both proteins and oligonucleotides. These technologies utilise fast, handheld devices with disposable cartridges tailored to specifi c applications. Additionally, they hold promise for use in low-resource settings and during health crises like epidemics.
The vision of a comprehensive healthcare system that extends its focus beyond human health to encompass animals and plants is depicted in Figure 1. In this envisioned scenario, individuals, whether they are patients or farmers, can collect samples such as saliva, blood, urine, or sap from animals or plants in a remote location. These samples are then placed on a disposable cartridge, such as the bioelectronic SiMoT cartridge, which is connected to a handheld electronic reader resembling a glucometer. This reader can transmit data to a smart device via Bluetooth or USB, which in turn uploads the data to a cloud platform. An artifi cial intelligence algorithm analyses the data, and the results are relayed back to the patient’s smart device. This process can be adapted for various POCT technologies, including lateral fl ow devices based on the CRISPR principle.
To realise this dream healthcare ecosystem, comprehensive screening of the general population, including all living organisms, using POCT technologies is crucial. Early screening is a cornerstone of preventive medicine, enhancing treatment success rates for diseases like cancer, cardiovascular conditions, and diabetes. Early detection allows for more effective and less invasive treatment options, leading to improved patient outcomes and reduced disease progression. Moreover, early screening can lower healthcare costs by avoiding expensive interventions and hospitalisations associated with advanced disease stages. It also improves quality of life by preventing complications and reducing the impact of symptoms on daily activities.
Screening is also vital for preventing the spread of infectious diseases. Identifying and isolating infected individuals early can contain outbreaks and protect public health. Additionally, screening contributes to health equity by ensuring timely and effective healthcare for individuals from all backgrounds.
Figure 1: The vision of the asymptomatic screening with a POCT technology in a one- healthcare ecosystem (reproduced with permission from ref. E. Macchia et al., Adv. Mater. 2024, 36, 2309705.
POCT technologies play a crucial role in implementing widespread screening programs. The World Health Organization has established criteria for ideal POCT technologies, summarised by the acronym ‘REASSURED’. (K. J. Land, at al. Nat. Microbiol. 2019, 4, 46). These criteria include affordability, sensitivity, specificity, user-friendliness, rapid results, robustness, equipment-free operation, connectivity, real-time insights, minimal sample requirements, versatility, stability, embedded quality control, regulatory approval, scalability, diagnostic range, and global accessibility.
Integrating POCT screening with the one-health approach acknowledges the interconnectedness of human, animal, and environmental health. This integration can guide screening efforts in populations exposed to zoonotic diseases and aid in epidemiological surveillance across species. Monitoring wildlife populations is also relevant for detecting and preventing the spread of diseases.
Realising the vision of a comprehensive healthcare system that considers the health of all living organisms requires widespread screening using POCT technologies. These technologies must meet stringent criteria to ensure effectiveness, accessibility, and ethical use. Integrating screening efforts with the one-health approach can enhance disease prevention, surveillance, and control, ultimately promoting health and well-being for all living beings and the ecosystems they inhabit.
The SiMoT technology represents a signifi cant leap forward in point-of-care testing (POCT), with two platforms reaching Technology Readiness Levels (TRL) 5-6, indicating validation in relevant environments and pre-clinical studies. These platforms offer distinct advantages, catering to different needs in healthcare settings. One platform features a single biofunctionalized electrode, ideal for assessing single markers/ pathogens, while the other is a 96-well ELISA-like array capable of multiplexing, enabling simultaneous analysis of multiple markers, such as those found in the blood of pancreatic cancer patients.
The single-sensor platform is particularly noteworthy for its user-friendly design and cost-effectiveness. It is engineered to be accessible even to untrained individuals, making it suitable for use in remote or resource-limited settings commonly found in underdeveloped countries. On the other hand, the array technology, while more
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