Aptamer-Based Point-of-Care Devices: Emerging Technologies and Integration of Computational Methods

Nanobiosensors based on on-site detection approaches for rapid pesticide sensing in the agricultural arena: A systematic review of the current status and perspectives

The extensive use of chemical pesticides has significantly boosted agricultural food crop yields. Nevertheless, their excessive and unregulated application has resulted in food contamination and pollution in environmental, aquatic, and agricultural ecosystems. Consequently, the on-site monitoring of pesticide residues in agricultural practices is paramount to safeguard global food and conservational safety. Traditional pesticide detection methods are cumbersome and ill-suited for on-site pesticide finding. The systematic review provides an in-depth analysis of the current status and perspectives of nanobiosensors (NBS) for pesticide detection in the agricultural arena. Furthermore, the study encompasses the fundamental principles of NBS, the various transduction mechanisms employed, and their incorporation into on-site detection platforms. Conversely, the assortment of transduction mechanisms, including optical, electrochemical, and piezoelectric tactics, is deliberated in detail, emphasizing its advantages and limitations in pesticide perception. Incorporating NBS into on-site detection platforms confirms a vital feature of their pertinence. The evaluation reflects the integration of NBS into lab-on-a-chip systems, handheld devices, and wireless sensor networks, permitting real-time monitoring and data-driven decision-making in agronomic settings. The potential for robotics and automation in pesticide detection is also scrutinized, highlighting their role in improving competence and accuracy. Finally, this systematic review provides a complete understanding of the current landscape of NBS for on-site pesticide sensing. Consequently, we anticipate that this review offers valuable insights that could form the foundation for creating innovative NBS applicable in various fields such as materials science, nanoscience, food technology and environmental science.

A Portable Readout System for Biomarker Detection with Aptamer-Modified CMOS ISFET Array

Biosensors based on ion-sensitive field effect transistors (ISFETs) combined with aptamers offer a promising and convenient solution for point-of-care testing applications due to the ability for fast and label-free detection of a wide range of biomarkers. Mobile and easy-to-use readout devices for the ISFET aptasensors would contribute to further development of the field. In this paper, the development of a portable PC-controlled device for detecting aptamer-target interactions using ISFETs is described. The device assembly allows selective modification of individual ISFETs with different oligonucleotides. Ta2O5-gated ISFET structures were optimized to minimize trapped charge and capacitive attenuation. Integrated CMOS readout circuits with linear transfer function were used to minimize the distortion of the original ISFET signal. An external analog signal digitizer with constant voltage and superimposed high-frequency sine wave reference voltage capabilities was designed to increase sensitivity when reading ISFET signals. The device performance was demonstrated with the aptamer-driven detection of troponin I in both reference voltage setting modes. The sine wave reference voltage measurement method reduced the level of drift over time and enabled a lowering of the minimum detectable analyte concentration. In this mode (constant voltage 2.4 V and 10 kHz 0.1Vp-p), the device allowed the detection of troponin I with a limit of detection of 3.27 ng/mL. Discrimination of acute myocardial infarction was demonstrated with the developed device. The ISFET device provides a platform for the multiplexed detection of different biomarkers in point-of-care testing.

Advancing 3D printed microfluidics with computational methods for sweat analysis

The intricate tapestry of biomarkers, including proteins, lipids, carbohydrates, vesicles, and nucleic acids within sweat, exhibits a profound correlation with the ones in the bloodstream. The facile extraction of samples from sweat glands has recently positioned sweat sampling at the forefront of non-invasive health monitoring and diagnostics. While extant platforms for sweat analysis exist, the imperative for portability, cost-effectiveness, ease of manufacture, and expeditious turnaround underscores the necessity for parameters that transcend conventional considerations. In this regard, 3D printed microfluidic devices emerge as promising systems, offering a harmonious fusion of attributes such as multifunctional integration, flexibility, biocompatibility, a controlled closed environment, and a minimal requisite analyte volume-features that leverage their prominence in the realm of sweat analysis. However, formidable challenges, including high throughput demands, chemical interactions intrinsic to the printing materials, size constraints, and durability concerns, beset the landscape of 3D printed microfluidic devices. Within this paradigm, we expound upon the foundational aspects of 3D printed microfluidic devices and proffer a distinctive perspective by delving into the computational study of printing materials utilizing density functional theory (DFT) and molecular dynamics (MD) methodologies. This multifaceted approach serves manifold purposes: (i) understanding the complexity of microfluidic systems, (ii) facilitating comprehensive analyses, (iii) saving both cost and time, (iv) improving design optimization, and (v) augmenting resolution. In a nutshell, the allure of 3D printing lies in its capacity for affordable and expeditious production, offering seamless integration of diverse components into microfluidic devices-a testament to their inherent utility in the domain of sweat analysis. The synergistic fusion of computational assessment methodologies with materials science not only optimizes analysis and production processes, but also expedites their widespread accessibility, ensuring continuous biomarker monitoring from sweat for end-users.

Aptamer-enhanced particle aggregation inhibition assay for simple homogeneous protein detection using DNA aptamer and thermo-responsive magnetic nanoparticles

A simple and sensitive homogeneous protein detection system is required for the early detection of biomarkers. Thermo-responsive magnetic particles (TM) have already been developed to achieve easy bound/free separation at the homogeneous protein detection system, but they are still limited owing to the requirement of secondary antibodies and negatively charged polymers, and it is challenging to control the TM aggregation behavior because of the size of the TM. Therefore, at new method to control TM aggregation behavior that is simple, easy, and highly sensitive is required. In this study, we developed a DNA aptamer-based TM assay as a simple protein detection system without additional secondary molecular recognition elements or negatively charged polymer. In the first attempt, a DNA aptamer was modified on the TM surface, and its aggregation behavior was monitored depending on the target molecule concentration. The TM aggregation rate during the heating process decreased depending on the amount of the DNA aptamer and increased depending on the target protein level. This suggests that the DNA aptamer prevented TM aggregation owing to its negative charge and achieved target protein detection owing to the cancellation of repulsion. Capturable aptamers were used in the TM assay to improve the sensitivity and limit of detection. The designed Capture DNA was modified on the TM surface, and the aptamer was captured in the presence of the target protein through a conformational change. Eventually, Capturable aptamer-based TM assay achieved a sub-nanomolar limit of detection and higher sensitivity than that of our initial investigation. Through this study and the ease of the DNA aptamer design, it was shown that the DNA aptamer-modified TM assay enabled the development of a simple and sensitive homogeneous protein detection system.

Metallic nanostructure-based aptasensors for robust detection of proteins

There is a significant need for fast, cost-effective, and highly sensitive protein target detection, particularly in the fields of food, environmental monitoring, and healthcare. The integration of high-affinity aptamers with metal-based nanomaterials has played a crucial role in advancing the development of innovative aptasensors tailored for the precise detection of specific proteins. Aptamers offer several advantages over commonly used molecular recognition methods, such as antibodies. Recently, a variety of metal-based aptasensors have been established. These metallic nanomaterials encompass noble metal nanoparticles, metal oxides, metal-carbon nanotubes, carbon quantum dots, graphene-conjugated metallic nanostructures, as well as their nanocomposites, metal-organic frameworks (MOFs), and MXenes. In general, these materials provide enhanced sensitivity through signal amplification and transduction mechanisms. This review primarily focuses on the advancement of aptasensors based on metallic materials for the highly sensitive detection of protein targets, including enzymes and growth factors. Additionally, it sheds light on the challenges encountered in this field and outlines future prospects. We firmly believe that this review will offer a comprehensive overview and fresh insights into metallic nanomaterials-based aptasensors and their capabilities, paving the way for the development of innovative point-of-care (POC) diagnostic devices.

Aptasensors Based on Non-Enzymatic Peroxidase Mimics: Current Progress and Challenges

Immunoassays based on antibodies as recognizing elements and enzymes as signal-generating modules are extensively used now in clinical lab diagnostics, food, and environmental analyses. However, the application of natural enzymes and antibodies has some drawbacks, such as relatively high manufacturing costs, thermal instability, and lot-to-lot variations that lower the reproducibility of results. Oligonucleotide aptamers are able to specifically bind their targets with high affinity and selectivity, so they represent a prospective alternative to protein antibodies for analyte recognition. Their main advantages include thermal stability and long shelf life, cost-efficient chemical synthesis, and negligible batch-to-batch variations. At the same time, a wide variety of non-protein peroxidase mimics are now available that show strong potential to replace protein enzymes. Here, we review and analyze non-protein biosensors that represent a nexus of these two concepts: aptamer-based sensors (aptasensors) with optical detection (colorimetric, luminescent, or fluorescent) based on different peroxidase mimics, such as DNAzymes, nanoparticles, or metal-organic frameworks.

Aptasensors: employing molecular probes for precise medical diagnostics and drug monitoring

Accurate detection and monitoring of therapeutic drug levels are vital for effective patient care and treatment management. Aptamers, composed of single-stranded DNA or RNA molecules, are integral components of biosensors designed for both qualitative and quantitative detection of biological samples. Aptasensors play crucial roles in target identification, validation, detection of drug-target interactions and screening potential of drug candidates. This review focuses on the pivotal role of aptasensors in early disease detection, particularly in identifying biomarkers associated with various diseases such as cancer, infectious diseases and cardiovascular disorders. Aptasensors have demonstrated exceptional potential in enhancing disease diagnostics and monitoring therapeutic drug levels. Aptamer-based biosensors represent a transformative technology in the field of healthcare, enabling precise diagnostics, drug monitoring and disease detection.

Drug Delivery Systems for Personal Healthcare by Smart Wearable Patch System

Smart wearable patch systems that combine biosensing and therapeutic components have emerged as promising approaches for personalized healthcare and therapeutic platforms that enable self-administered, noninvasive, user-friendly, and long-acting smart drug delivery. Sensing components can continuously monitor physiological and biochemical parameters, and the monitoring signals can be transferred to various stimuli using actuators. In therapeutic components, stimuli-responsive carrier-based drug delivery systems (DDSs) provide on-demand drug delivery in a closed-loop manner. This review provides an overview of the recent advances in smart wearable patch systems, focusing on sensing components, stimuli, and therapeutic components. Additionally, this review highlights the potential of fully integrated smart wearable patch systems for personalized medicine. Furthermore, challenges associated with the clinical applications of this system and future perspectives are discussed, including issues related to drug loading and reloading, biocompatibility, accuracy of sensing and drug delivery, and largescale fabrication.