Smartphone paired SIM card-type integrated creatinine biosensor

Urine Test Strip Quantitative Assay with a Smartphone Camera

Urine test strips for urinalysis are a common diagnostic tool with minimal costs and are used in various situations including homecare and hospitalization. The coloration scaled by the naked eye is simple, but it is suitable for semiquantitative analysis only. In this paper, a colorimetric assay is developed based on a smartphone digital camera and urine test strips. Assays of pH, albumin, glucose, and lipase activity were performed as a tool for the diagnosis of aciduria, alkaluria, glycosuria, proteinuria, and leukocyturia. The RGB color channels were analyzed in the colorimetric assay, and the assay exerted good sensitivity, and all the particular diagnoses proved to be reliable. The limits of detection for glucose (0.11 mmol/L), albumin (0.15 g/L), and lipase (2.50 U/μL) were low enough to cover the expected physiological concentration, and the range for pH was also satisfactory. The urine test strips with a camera as an output detector proved applicability to spiked urine samples, and the results were also well in comparison to the standard assays which confirms the practical relevance of the presented findings.

A Low-cost Creatinine Biosensor by Differential Optical Signal Readout for the Whole Blood Analysis

This study developed a low-cost paper-based biosensor for point-of-care (POC) detection of blood creatinine by using differential optical signal readout. Dual-channel photochemical paper-based test strips were fabricated with stackable multilayer films containing pre-immobilized enzymes and reagents for the identification and conversion of creatinine and creatine. Enzyme-linked reactions generated hydrogen peroxide (H2O2), which formed a blue oxidized condensate with aniline derivatives. The color depth was quantified via the differential optical signal of the two channels and positively correlated with the concentration of the analyte. This method was first proposed to address the issue of endogenous interferences in the enzymatic assay of creatinine, greatly improving the detection accuracy. The proposed biosensor was calibrated with spiked blood samples, and achieved a wide detection range of 31-1483 μmol/L, showing superior detection performance to general enzymatic methods, especially in the low concentration range. Creatine interference testing demonstrated that the biosensor could resist the interference of ≤ 300 μmol/L endogenous creatine. It is believed that the proposed optical differential biosensor for blood creatinine could enable to pave the way for a daily monitoring system for renal diseases.Clinical Relevance- This stackable multilayer paper-based biosensor provides an enzymatic colorimetric assay of creatinine in whole blood, which can be read out by the differential optical signal to exclude interference from endogenous creatine.

Nucleic acid aptamer-based biosensors and their application in thrombin analysis

Thrombin is a multifunctional serine protease that plays an important role in coagulation and anticoagulation processes. Aptamers have been widely applied in biosensors due to their high specificity, low cost and good biocompatibility. This review summarizes recent advances in thrombin quantification using aptamer-based biosensors. The primary focus is optical sensors and electrochemical sensors, along with their applications in thrombin analysis and disease diagnosis.

A smartphone-connected point-of-care photochemical biosensor for the determination of whole blood creatinine by differential optical signal readout

The level of creatinine in the human body has clinical implications with regard to a potential association with kidney, muscle, and thyroid dysfunction, hence necessitating fast and accurate detection, especially at the point-of-care (POC) level. This paper presents the design, fabrication, and feasibility of a compact, low-cost and reliable POC photochemical biosensor connected to a smartphone for the determination of whole blood creatinine by differential optical signal readout. Disposable, dual-channel paper-based test strips were fabricated using stackable multilayer films pre-immobilized with enzymes and reagents for the identification and conversion of creatinine and creatine, resulting in dramatic colorimetric signals. A handheld optical reader was integrated with dual-channel differential optical readout to address endogenous interferences in the enzymatic assay of creatinine. We demonstrated this differential concept with spiked blood samples, obtaining a wide detection range of 20-1483 μmol/L and a low detection limit of 0.03 μmol/L. Further interference experiments displayed the differential measuring system's excellent performance against endogenous interference. Furthermore, the sensor's high reliability was confirmed through comparison with the laboratory method, with the results of 43 clinical tests consistent with the bulky automatic biochemical analyzer, with its correlation coefficient R² = 0.9782. Additionally, the designed optical reader is Bluetooth-enabled and can connect to a cloud-based smartphone to transmit test data, enabling active health management or remote monitoring. We believe the biosensor has the potential to be an alternative to the current creatinine analysis conducted in hospitals and clinical laboratories, and it has promising prospects for contributing to the development of POC devices.

Electrochemical Creatinine (Bio)Sensors for Point-of-Care Diagnosis of Renal Malfunction and Chronic Kidney Disorders

In the post-pandemic era, point-of-care (POC) diagnosis of diseases is an important research frontier. Modern portable electrochemical (bio)sensors enable the design of POC diagnostics for the identification of diseases and regular healthcare monitoring. Herein, we present a critical review of the electrochemical creatinine (bio)sensors. These sensors either make use of biological receptors such as enzymes or employ synthetic responsive materials, which provide a sensitive interface for creatinine-specific interactions. The characteristics of different receptors and electrochemical devices are discussed, along with their limitations. The major challenges in the development of affordable and deliverable creatinine diagnostics and the drawbacks of enzymatic and enzymeless electrochemical biosensors are elaborated, especially considering their analytical performance parameters. These revolutionary devices have potential biomedical applications ranging from early POC diagnosis of chronic kidney disease (CKD) and other kidney-related illnesses to routine monitoring of creatinine in elderly and at-risk humans.

Biomedical Applications of Microfluidic Devices: A Review

Both passive and active microfluidic chips are used in many biomedical and chemical applications to support fluid mixing, particle manipulations, and signal detection. Passive microfluidic devices are geometry-dependent, and their uses are rather limited. Active microfluidic devices include sensors or detectors that transduce chemical, biological, and physical changes into electrical or optical signals. Also, they are transduction devices that detect biological and chemical changes in biomedical applications, and they are highly versatile microfluidic tools for disease diagnosis and organ modeling. This review provides a comprehensive overview of the significant advances that have been made in the development of microfluidics devices. We will discuss the function of microfluidic devices as micromixers or as sorters of cells and substances (e.g., microfiltration, flow or displacement, and trapping). Microfluidic devices are fabricated using a range of techniques, including molding, etching, three-dimensional printing, and nanofabrication. Their broad utility lies in the detection of diagnostic biomarkers and organ-on-chip approaches that permit disease modeling in cancer, as well as uses in neurological, cardiovascular, hepatic, and pulmonary diseases. Biosensor applications allow for point-of-care testing, using assays based on enzymes, nanozymes, antibodies, or nucleic acids (DNA or RNA). An anticipated development in the field includes the optimization of techniques for the fabrication of microfluidic devices using biocompatible materials. These developments will increase biomedical versatility, reduce diagnostic costs, and accelerate diagnosis time of microfluidics technology.