Enzymeless creatinine estimation using poly(3,4-ethylenedioxythiophene) -β-cyclodextrin

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.

Non-enzymatic electrochemical detection of creatinine based on a glassy carbon electrode modified with a Pd/Cu2O decorated polypyrrole (PPy) nanocomposite: an analytical approach

The major constraints of standard enzymatic biosensors are poor long-term storage stability and high cost. Hence, there is extensive research towards fabrication of reliable enzymeless biosensors based on nanomaterials. In this paper, we present the development of an enzymeless electrochemical biosensor for highly precise detection of creatinine. This involves the use of a simple yet effective alternative to the commonly utilized Pd/Cu₂O/PPy nanocomposite, which was characterized by different analytical methods. The present electrochemical sensor provides a wide detection range (0.1 to 150 μM), low detection limit (0.05 μM) and high sensitivity (0.207 μA), and is capable of detecting the creatinine level in human urine samples, which are inexpensive. The results are reproducible, and the sensor is stable. The sensor demonstrates good electrocatalytic activity and selectivity towards the detection of creatinine in the presence of various other similar biological entities. When compared to other existing counterparts, the electrocatalytic behaviour of the present sensor is comparable, if not better. So, the present electrochemical sensor for creatinine might be employed as a long-term diagnostic alternative.

Electrochemical Biosensor for SARS-CoV-2 cDNA Detection Using AuPs-Modified 3D-Printed Graphene Electrodes

A low-cost and disposable graphene polylactic (G-PLA) 3D-printed electrode modified with gold particles (AuPs) was explored to detect the cDNA of SARS-CoV-2 and creatinine, a potential biomarker for COVID-19. For that, a simple, non-enzymatic electrochemical sensor, based on a Au-modified G-PLA platform was applied. The AuPs deposited on the electrode were involved in a complexation reaction with creatinine, resulting in a decrease in the analytical response, and thus providing a fast and simple electroanalytical device. Physicochemical characterizations were performed by SEM, EIS, FTIR, and cyclic voltammetry. Square wave voltammetry was employed for the creatinine detection, and the sensor presented a linear response with a detection limit of 0.016 mmol L−1. Finally, a biosensor for the detection of SARS-CoV-2 was developed based on the immobilization of a capture sequence of the viral cDNA upon the Au-modified 3D-printed electrode. The concentration, immobilization time, and hybridization time were evaluated in presence of the DNA target, resulting in a biosensor with rapid and low-cost analysis, capable of sensing the cDNA of the virus with a good limit of detection (0.30 µmol L−1), and high sensitivity (0.583 µA µmol−1 L). Reproducible results were obtained (RSD = 1.14%, n = 3), attesting to the potentiality of 3D-printed platforms for the production of biosensors.

A review of recent advances in non-enzymatic electrochemical creatinine biosensing

Creatinine biosensing is a rapidly developing field owing to the clinical relevance of creatinine as a vital biomarker for several diseases associated with renal, thyroidal, and muscular dysfunctions. Over the years, we have observed numerous creatinine biosensing strategies, including the most widely studied enzymatic creatinine biosensors. Though the enzymatic approach provides excellent selectivity and reliability, it has certain drawbacks, which include high fabrication cost and poor storage stability (that is inherent to every enzyme-based biosensors). This has led to the development of non-enzymatic creatinine biosensors, of which electrochemical sensors are the most promising for point-of-care applications. However, only a limited number of studies have been conducted and there is a lack of reviews addressing the recent advances in this research area. Herein, we present for the first time, a review with a prime focus on the various strategies implemented in non-enzymatic electrochemical creatinine biosensing. We aim to offer a comprehensive context on the achievements and limitations of currently available non-enzymatic electrochemical creatinine biosensors and address the underlying factors pertaining to the interplay of modification/fabrication techniques with the sensitivity, selectivity, interferences, and long-term storage stability of the biosensor. We hope that this work shall prove to be seminal in the conception and advancement of future non-enzymatic electrochemical creatinine biosensors.

Trend in creatinine determining methods: Conventional methods to molecular‐based methods

Renal failure (RF) disease is ranked as one of the most prevalent diseases with severe morbidity and mortality. Early diagnosis of RF leads to subsequent control of disease to reduce the poor prognosis. The level of sera creatinine is considered as a significant biomarker for kidney biofunction, which is routinely detected by the Jaffe reaction. The normal range for creatinine in the blood may be 0.84‐1.21 mg/dL. Low accuracy, insufficient sensitivity, explosive and toxicity of picric acid, and pseudo‐interaction with nonspecific elements such as ammonium ions in the Jaffe method lead to the development of various techniques for precise detection of creatinine such as spectroscopic, electrochemical, and chromatography approaches and sensors based on enzymes, molecular imprinted polymer and nanoparticles, etc. Based on previously established results, they are trying to construct sensors with high accuracy, optimum sensitivity, acceptable linear/calibration range, and limit of detection, which are small in size and applicable by the patient him/herself (point‐of‐care testing). By comparing the results of research, a molecularly imprinted electrochemiluminescence‐based sensor with linear/calibration range of 5‐1 mMconcentration of creatinine and the detection limit of 0.5 nM has the best detectable resolution with 2 million measurable points. In this paper, we will review the recently developed methods for measuring creatinine concentration and renal biofunction.

da Silva Alves D, Okeke C, Breslin CB. Cyclodextrins as Supramolecular Recognition Systems: Applications in the Fabrication of Electrochemical Sensors

Supramolecular chemistry, although focused mainly on noncovalent intermolecular and intramolecular interactions, which are considerably weaker than covalent interactions, can be employed to fabricate sensors with a remarkable affinity for a target analyte. In this review the development of cyclodextrin-based electrochemical sensors is described and discussed. Following a short introduction to the general properties of cyclodextrins and their ability to form inclusion complexes, the cyclodextrin-based sensors are introduced. This includes the combination of cyclodextrins with reduced graphene oxide, carbon nanotubes, conducting polymers, enzymes and aptamers, and electropolymerized cyclodextrin films. The applications of these materials as chiral recognition agents and biosensors and in the electrochemical detection of environmental contaminants, biomolecules and amino acids, drugs and flavonoids are reviewed and compared. Based on the papers reviewed, it is clear that cyclodextrins are promising molecular recognition agents in the creation of electrochemical sensors, chiral sensors, and biosensors. Moreover, they have been combined with a host of materials to enhance the detection of the target analytes. Nevertheless, challenges remain, including the development of more robust methods for the integration of cyclodextrins into the sensing unit.

Advances in the Detection, Mechanism and Therapy of Chronic Kidney Disease

Chronic Kidney Disease (CKD) is characterized by the gradual loss of renal mass and functions. It has become a global health problem, with hundreds of millions of people being affected. Both its incidence and prevalence are increasing over time. More than $20,000 are spent on each patient per year. The economic burden on the patients, as well as the society, is heavy and their life quality worsen over time. However, there are still limited effective therapeutic strategies for CKD. Patients mainly rely on dialysis and renal transplantation, which cannot prevent all the complications of CKD. Great efforts are needed in understanding the nature of CKD progression as well as developing effective therapeutic methods, including pharmacological agents. This paper reviews three aspects in the research of CKD that may show great interests to those who devote to bioanalysis, biomedicine and drug development, including important endogenous biomarkers quantification, mechanisms underlying CKD progression and current status of CKD therapy.

Enzyme-less sensing of the kidney dysfunction biomarker creatinine using an inulin based bio-nanocomposite

Enzyme-less electrochemical sensing of creatinine using an inulin-based bio-nanocomposite.

Biosensing methods for determination of creatinine: A review

Creatinine is a metabolic product of creatine phosphate in muscles, which provides energy to muscle tissues. Creatinine has been considered as indicator of renal function specifically after dialysis, thyroid malfunction and muscle damage. The normal level of creatinine in the serum and its excretion through urine in apparently healthy individuals is 45-140 μM and 0.8-2.0 gm/day respectively. The level of creatinine reaches >1000 μM in serum during renal, thyroid and kidney dysfunction or muscle disorder. A number of conventional methods such as colorimetric, spectrophotometric and chromatographic are available for determination of creatinine. Besides the advantages of being highly sensitive and selective, these methods have some drawbacks like time-consuming, requirement of sample pre-treatment, high cost instrumental set-up and skilled persons to operate. The sensors/biosensors overcome these drawbacks, as these are fast, easy, cost effective and highly sensitive. This review article describes the classification, operating principles, merits and demerits of various creatinine sensors/biosensors, specifically nanomaterials based biosensors. Creatinine biosensors work optimally within 2-900 s, potential range 0.1-1.0 V, pH range 4.0-10.0, temperature range 25-35 °C and had linear range, 0.004-30000 µM for creatinine with the detection limit between 0.01.01 µM and 520 µM. These biosensors measured creatinine level in sera and urine samples and had storage stability between 4 and 390 days, while being stored dry at 4 °C. The future perspective for further improvement and commercialization of creatinine biosensors are discussed.

A novel and effective surface design: conducting polymer/β-cyclodextrin host-guest system for cholesterol biosensor

The combination of supramolecules and conducting polymers (CPs) has gained much attention for the development of new immobilization matrices for biomolecules. Herein, an amperometric biosensor based on a novel conducting polymer, poly(2-(2-octyldodecyl)-4,7-di(selenoph-2-yl)-2H-benzo[d][1,2,3]triazole)) (PSBTz) and β-cyclodextrin (β-CD) for the detection of cholesterol, was constructed. The PSBTz film with β-CD was deposited on a graphite electrode by electropolymerization technique to achieve a suitable matrix for enzyme immobilization. Moreover, to justify the immobilization, alkyl chain containing conducting polymer (PSBTz) was designed, synthesized and electrochemically polymerized on the transducer surface. Alkyl chains in the structure of SBTz and hydroxyl groups of β-CD contributed to effective immobilization while protecting the suitable orientation of the biomolecule. Cholesterol oxidase (ChOx) was covalently immobilized onto the modified surface using N,N′-carbonyldiimidazole (CDI) as the cross-linking agent. After successful immobilization, amperometric biosensor responses were recorded at −0.7 V vs Ag/AgCl in phosphate buffer (pH 7.0). The apparent Michaelis-Menten constant (KM(app)), maximum current (Imax), limit of detection (LOD), and sensitivity values were determined: 28.9 μM, 12.1 μA, 0.005 μM, and 5.77 μA/μM cm(2), respectively. The fabricated biosensor was characterized using scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Finally, the prepared biosensor was successfully applied for the determination of cholesterol in blood samples.