An impedimetric immunosensor based on chitosan-Au nanoparticles-reduced graphene oxide nanosheet composite modified PG electrode for detection of brain natriuretic peptide.

An ultrasensitive impedimetric immunosensor was developed to detect brain natriuretic peptide (BNP) for early diagnosis of heart failure. To construct this immunosensor, anti-BNP antibodies were immobilized covalently onto nanocomposite of chitosan-Au nanoparticles and reduced graphene oxide nanosheets (CHIT-Au@rGONs) electrodeposited onto pencil graphite electrode. This approach impedes charge transfer resistance (Rct) value proportionally to the BNP captured by antigen-antibody interactions. The observed Rct values by this immunosensor, were correlated with linear concentrations of BNP in the range, 1 × 10-2 to 1 × 103 pg/mL, with a limit of detection of 12 pg/mL and limit of quantification of 36.3 pg/mL. The immunosensor detected BNP in spiked human sera. The analytic recovery of added BNP in human sera was 97.04%. The present method was fairly consistent with commercial approach. The working electrode was stored for 2 months in cold. BSA-IgG had no interference in the electrode activity showing its high specificity for BNP. This novel approach provided a new POC-diagnostics, as direct sample measurements are easier and more efficient by this immunosensor compared to existing immunosensors. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03704-x.

Amperometric detection of tumor suppressor protein p53 via pencil graphite electrode for fast cancer diagnosis.

Cancer occupies the second place in terms of worldwide mortality. Early and fast diagnosis of cancer helps clinicians to expand therapeutic approaches ultimately leading towards early diagnosis of cancer patients. In the present work, we delineated an amperometric immunosensor to diagnose cancer to detect p53, a biomarker for cancer. The immunosensor was fabricated by immobilizing anti-p53 antibodies onto the pencil graphite electrode (PGE). The immobilization of probe was studied by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The immunosensor was optimized for pH, incubation temperature, antibody concentration, incubation time and antigen concentration. The developed immunosensor, showed a linear range between 10 pgmL-1 to 10 ngmL-1 with a detection limit (LOD) of 10 pgmL-1. p53 antigen was analyzed by measuring current under optimal conditions. The occurrence of p53 was determined in sera of prostate, breast, colon and lung cancer patients by the present immunosensor. The lower incubation time i.e., fast response and lower LOD demonstrated an improved p53 immunosensor for early diagnosis of cancer.

A Novel Amperometric Genosensor for Rapid Detection of Canine Parvovirus in Feces.

A highly sensitive novel amperometric genosensor has been developed for rapid detection of canine parvovirus (CPV) DNA in fecal swabs of naturally infected dogs. The genosensor is based on a single stranded 5°-thiolated (SH) DNA probe complementary to VP1/VP2 gene of canine parvo vaccine strain, immobilized covalently on a polycrystalline gold (Au) electrode. The genosensor has been characterized by scanning electron microscopy (SEM), Fourier Transform Infra-Red Spectroscopy (FTIR), cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectra (EIS). The ssDNA-SH/Au electrode was hybridized with single stranded target DNA (ss T-DNA) in the sample. This hybridization was detected by reduction in current, generated by interaction of methylene blue (MB) with free guanine of ssDNA. The current response of genosensor was determined by CV, DPV and EIS. The sensor detected single stranded genomic DNA (ss g-DNA) isolated from vaccine strain of CPV in the range, 1.0-12.0 ng/µl at 25 °C for 10 min. Subsequently, the genobiosensor was applied for detection of CPV viral DNA in fecal swabs of naturally infected dogs. The limit of detection (LOD) of the sensor was 1.0 ng/µl of fecal viral DNA. To the best of our knowledge, this is the first report on development and application of amperometric biosensor for rapid, sensitive, specific point of care detection of viral DNA of CPV in feces.

Organic Polymer and Metal Nano-particle Based Composites for Improvement of the Analytical Performance of Electrochemical Biosensors.

Metal nanoparticles (NPs) are described in the nanoscale and made from either pure metals or their compounds such as oxides. Metallic NPs have certain indistinct functional groups due to which these can bind with any type of ligand, antibody and drugs. Organic polymers, which conduct electricity, are called conducting polymers (intrinsically conducting polymers). They behave like semiconductors by exhibiting metallic conductivity. Process-ability is the major advantage of conducting polymers. Nanocomposite is a novel material having nano-fillers scattered in a matrix with morphology and interfacial characteristics of nano-composites including their individual property that influence their characteristics. Conducting polymers and NP composites can enhance the rate of electron transport between the current collector material (electrode) and the electrolyte; therefore they have been employed in the construction of improved electrochemical sensors such as amperometric, catalytic and potentiodynamic affinity sensors.

Detection methods for influenza A H1N1 virus with special reference to biosensors: a review.

H1N1 (Swine flu) is caused by influenza A virus, which is a member of Orthomyxoviridae family. Transmission of H1N1 occurs from human to human through air or sometimes from pigs to humans. The influenza virus has different RNA segments, which can reassert to make new virus strain with the possibility to create an outbreak in unimmunized people. Gene reassortment is a process through which new strains are emerging in pigs, as it has specific receptors for both human influenza and avian influenza viruses. H1N1 binds specifically with an α-2,6 glycosidic bond, which is present in human respiratory tract cells as well as in pigs. Considering the fact of fast multiplication of viruses inside the living cells, rapid detection methods need an hour. Currently, WHO recommended methods for the detection of swine flu include real-time PCR in specific testing centres that take 3-4 h. More recently, a number of methods such as Antigen-Antibody or RT-LAMP and DNA biosensors have also been developed that are rapid and more sensitive. This review describes the various challenges in the diagnosis of H1N1, and merits and demerits of conventional vis-à-vis latest methods with special emphasis on biosensors.

Detection of tumor suppressor protein p53 with special emphasis on biosensors: A review.

Cancer is a general word, which specifies a cluster of diseases affecting almost every-body part. Cancer is a second leading cause of death, globally. The tumor suppressor protein p53 is known to play a vital role in prevention of cancer. The enhanced and active form of p53 controls target gene expression through binding with DNA response elements (REs) and thus inhibits tumor cell growth. p53 is found mutated in more than 50% of the cancers. The wide mutation spectrum of p53 gene underlies the process of tumor development. Hence, the accurate quantification of p53 protein levels has great importance in early diagnosis of cancer. The biosensors are the tools, which convert biological interactions into readout signals. These are the most simple, sensitive, specific, rapid and precise devices used for determination of altered protein levels. Hence, Bio sensing methods have great potential as a diagnostic tool for determination of p53 protein. This review describes the screening of most recent and different types of bio sensing approaches, reported for detection of p53. The review also discusses the necessity of biomarker based bio-sensing methods for early diagnosis of cancer. The overall aim of this review is to advance the future analytical approaches of p53 biosensors.

Fabrication and application of an amperometric lysine biosensor based on covalently immobilized lysine oxidase nanoparticles onto Au electrode.

The fabrication of an amperometric lysine biosensor is described in this study, wherein nanoparticles (NPs) of lysine oxidase (LOx) are covalently immobilized onto gold electrode (AuE). The LOxNPs were prepared by desolvation method and characterized by UV Vis spectroscopy, Fourier transform infra red (FTIR) spectroscopy and transmission electron microscopy (TEM). The LOxNPs/AuE modified working electrode was studied by scanning electron microscope (SEM) and cyclic voltammetric (CV) techniques. The electrode exhibited optimum current within 3.5 s at applied potential, 0.8 V, pH 6.5 and temperature, 35 °C. The sensor displayed a linear relationship between lysine concentration and current in the range 10-800 µM with a limit of detection of 10 µM. Within assay and between batch coefficients of variation were 0.0751% and 0.0637% respectively. The analytical recoveries of added lysine at 10 µM and 20 µM in sera were 98.39% and 98.23% respectively. There was a good correlation between level of lysine in sera and milk samples (R2 = 0.999 and R2 = 0.98 respectively) as determined by the standard spectrophotometric method and the present method. The biosensor measured lysine levels in milk, pharmaceutical tablet and sera of healthy individuals and cancer patients. The biosensor showed slight interference by common interferents found in serum.

Fabrication of an improved amperometric creatinine biosensor based on enzymes nanoparticles bound to Au electrode.

An improved amperometric creatinine biosensor was fabricated that dependent on covalent immobilisation of nanoparticles of creatininase (CANPs), creatinase (CINPs) and sarcosine oxidase (SOxNPs) onto gold electrode (AuE). The CANPs/CINPs/SOxNPs/AuE was characterised by scanning electron microscopy and cyclic voltammetry at various stages. The working electrode exhibited optimal response within 2 s at a potential of 0.6 V, against Ag/AgCl, pH 6.5 and 30 °C. A linear relationship was observed between creatinine concentration range, 0.1-200µM and biosensor response i.e. current in mA, under optimum conditions. Biosensor offered a low detection limit of 0.1 µM with long storage stability. Analytical recoveries of added creatinine in blood sera at 0.5 mM and at 1.0 mM concentrations, were 92.0% and 79.20% respectively. The precision i.e. within and between-batch coefficients of variation were 2.04% and 3.06% respectively. There was a good correlation (R2 = 0.99) between level of creatinine in sera, as calculated by the colorimetric method and present electrode. The CANPs/CINPs/SOxNPs/Au electrode was reused 200 times during the period of 180 days, with just 10% loss in its initial activity, while being stored at 4 °C, when not in use.HighlightsPrepared and characterised creatininase (CA), creatinase (CI) sarcosine oxidase (SOx) nanoparticles and immobilised them onto gold electrode (AuE) for fabrication of an improved amperometric creatinine biosensor.The biosensor displayed a limit of detection (LOD) of 0.1 µM with a linear working range of 0.1 µM-200 µM.The biosensor was evaluated and applied to measure elevated creatinine levels in sera from whom suffering from kidney and muscular disorders.The working electrode retained 90% of its initial activity, while being stored dry at 4 ˚C for 180 days.

Bio-sensing of organophosphorus pesticides: A review.

Organophosphorus (OP) pesticides have been used widely as agricultural and household pest control agents for almost five decades and persist in our water resources, fruits, vegetables and processed food as health and environmental hazardous compounds. Thus, detection of these harmful OP pesticides at an ease with high sensitivity and selectivity is the need of hour. Bio-sensing technology meet these requirements and has been employed at a large scale for detection. The present review is aimed mainly to provide the overview of the past and recent advances occurred in the field of biosensor technology employed for the detection of these OP compounds. The review describes the principle and strategy of various OP biosensors including electrochemical (amperometric, potentiometric), thermal, piezoelectric, optical (fluorescence, Surface Plasmon Resonance (SPR)), microbial and DNA biosensors in detail. The electrochemical biosensors are generally, based on inhibition of enzyme, acetyl cholinesterase (AChE), butyryl cholinesterase (BChE), tyrosinase and alkaline phosphatase or enzyme (organophosphorus hydrolase, OPH)) catalyzed reaction. The detection limits and linearity range of various OP biosensors have also been compared. AChE inhibition based amperometric OP biosensors exhibited the lowest detection limit of 1 × 10-11 µM with a linearity range of 1.0 × 10-11 - 1.0 × 10-2 µM.

Quantitative analysis of sarcosine with special emphasis on biosensors: a review.

The quantitative determination of sarcosine is of great importance in clinical chemistry, food and fermentation industries. Elevated sarcosine levels are associated with Alzheimer, dementia, prostate cancer, colorectal cancer, stomach cancer and sarcosinemia. This review summarizes the various methods for quantitative analysis of sarcosine with special emphasis on various strategies of biosensors and their analytical performance. The current bio sensing methods have overcome the drawbacks of conventional methods. Sarcosine biosensors work optimally at pH 7.0 to 8.0 in the linear range of 0.1 to 100 µM within 2 to 17 s and between 25 and 37 °C, within a limit of detection (LOD) between 0.008 and 500 mM. The formulated biosensors can be reused within a stability period of 3-180 days. Future research could be focused to modify existing sarcosine biosensors, leading to simple, reliable, and economical sensors ideally suited for point-of-care treatment. Clinical significance Elevated sarcosine levels are associated with prostate and colorectal cancer, Alzheimer, dementia, stomach cancer and sarcosinemia. Quantitative determination of sarcosine is of great importance in clinical chemistry as well as food and fermentation industries. Attempts made in development of sarcosine biosensors have been reviewed with their advantages and disadvantages, so that scientist and clinicians can improvise the methods of developing more potent sarcosine biosensor applicable in multitudinous fields. This is the first comprehensive review which compares the various immobilization methods, sensing principles, strategies used in biosensors and their analytical performance in detail.

Correction to: Voltammetric detection of anti-HIV replication drug based on novel nanocomposite gold-nanoparticle-CaCO3 hybrid material.

The Figs. 2, 4 and 5 were published wrongly in this paper, due to inadvertent compilation of figures during uploading the paper.

Determination of urea with special emphasis on biosensors: A review.

Urea is the major end product of nitrogen metabolism in humans, which is eliminated from the body mainly by the kidneys through urine but is also secreted in body fluids such as blood and saliva. Its level in urine ranges from 7 to 20 mg/dL, which drastically rises under patho-physiological conditions thus providing key information of renal function and diagnosis of various kidney and liver disorders. Increase in urea levels in blood, also referred to as azotemia or uremia. The chronic kidney disease (CKD) or end stage renal disease (ESRD) is generally caused due to the progressive loss of kidney function. Hence, there is an urgent need of determination of urea in biological fluids to diagnose these diseases at their early stage. Among the various methods available for detection of urea, most are complicated and require time-consuming sample pre-treatment, expensive instrumental set-up and trained persons to operate, specifically for chromatographic methods. The biosensing methods overcome these drawbacks, as these are simple, fast, specific and highly sensitive and can also be applied for detection of urea in vivo. This review presents the principles of various analytical methods for determination of urea with special emphasis on biosensors. The use of various nanostructures and electrochemical microfluidic paper based analytical device (EµPAD) are suggested for further development of urea biosensors.

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.

Development of glycerol biosensor based on co-immobilization of enzyme nanoparticles onto graphene oxide nanoparticles decorated pencil graphite electrode.

An improved amperometric biosensor was fabricated by immobilizing glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) nanoparticles (NPs) onto graphene oxide nanoparticles (GrONPs) modified pencil graphite (PG) electrode. The GKNPs, GPONPs and GrONPs were characterized by UV spectroscopy, and transmission electron microscopy (TEM). The working electrode (GKNPs/GPONPs/GrONPs/PGE) was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. The biosensor exhibited optimal current response at an applied potential of 0.45 V, pH 8.0, and 35 °C. The biosensor displayed a wide linear response for glycerol concentration from 0.001 to 60 mM with a detection limit of 0.002 µM. Moreover, a very high sensitivity 121.45 µA·mM-1·cm-2, rapid response time (2 s) and a good concurrence with the standard enzymic colorimetric technique with a correlation coefficient (R2 = 0.99) was offered by the present biosensor. Evidently, biosensor revealed an analytical recovery of 98.5% after addition of glycerol to the sera samples. Within and between batches studies of working electrode demonstrated coefficients of variation of 0.098% and 0.101%, respectively. The biosensor measured blood serum glycerol level in patients suffering from hyperglyceridemia. The biosensor lost 25% of its initial activity after its regular use over a period of 210 days, at 4 °C storage condition.

Construction and application of amperometric sarcosine biosensor based on SOxNPs/AuE for determination of prostate cancer.

An improved amperometric sarcosine biosensor was constructed based on covalent immobilization of sarcosine oxidase nanoparticles (SOxNPs) onto gold electrode (AuE). The SOxNPs/AuE was characterized by scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS) at different stages of its construction. The biosensor worked optimally within 2 s at a potential of 1.0 V, against Ag/AgCl, pH 6.5 and 35 °C. A linear relationship was observed between sarcosine concentration range, 0.1-100 µM and the biosensor response i.e. current in mA under optimum conditions. The biosensor offered a low detection limit of 0.01 µM and gratifying storage stability. The SOxNPs/AuE was unaffected by a number of serum substances at their physiological concentrations. The biosensor measured sarcosine level in sera collected from persons suffering from prostate cancer (mean13.5 µM, n = 8), which was significantly higher (p < 0.01) than those in apparently healthy persons (mean 2.2 µM, n = 8). The SOxNPs/Au electrode was reused 300- times during the span of 180 days, with only 10% loss in its initial activity while being stored dry at 4 °C.

Biosensors for determination of D and L- amino acids: A review.

Amino acids (AAs) of nutritional importance exist as L-isomers, while D-isomeric form of AAs is common constituent of bacterial cell wall. The presence of D-amino acids in foods is promoted by harsh technological processes (e.g., high temperature, extreme pH, adulteration or microbial contamination). The detection of free AAs in different brain disorders is also very important. Among the various methods available for detection of AAs, most are complicated and require time-consuming sample pre-treatment, expensive instrumental set-up and trained persons to operate, specifically for chromatographic methods. The biosensing methods overcome these drawbacks, as these are simple, fast, specific and highly sensitive and can also be applied for detection of AAs in vivo. This review presents the principles, merits and demerits of various analytical methods for AA determination with special emphasis on D-amino acids (DAA) and L-amino acids (LAA) biosensors. The electrochemical AA biosensors work optimally within 2-900 s, pH range, 5.3-9.5; temperature range, 25-45 °C; AA concentration range, 0.0008-8000 mM, limit of detection(LOD) between 0.02 and 1250 µM and working potential from -0.05 to 0.45 V. These biosensors measured AA level in fruit juices, beverages, urine, sera and were reused 200 times over a period of 7-120 days. The use of various nanostructures and electrochemical microfluidic paper based analytical device (EµPAD) are suggested for further development of AA biosensors.

Dataset on fabrication of an improved L-lactate biosensor based on lactate oxidase/cMWCNT/CuNPs/PANI modified PG electrode.

The data shown in this article are based on the original research article entitled "An improved amperometric L-lactate biosensor based on covalent immobilization of microbial lactate oxidase onto carboxylated multiwalled carbon nanotubes/copper nanoparticles/ polyaniline modified pencil graphite electrode" (Dagar and Pundir, 2017) [1]. This article explains the fabrication of an amperometric L-lactate biosensor based on microbial lactate oxidase (LOx) covalent immobilization onto nanomatrix [(carboxylated multiwalled carbon nanotubes (cMWCNT)/copper nanoparticles (CuNPs)/polyaniline (PANI) hybrid film/pencil graphite electrode (PGE)]. The dataset based on this article is made publically available for critical analysis. The whole data is supplied in the research article instead of repository. The data in the article is not related to any already published article.

Fabrication of glycerol biosensor based on co-immobilization of enzyme nanoparticles onto pencil graphite electrode.

Glycerol kinase (GK) and glycerol-3- phosphate oxidase (GPO) nanoparticles (NPs) were prepared, characterized and immobilized onto pencil graphite (PG) electrode to fabricate an improved amperometric glycerol biosensor (GKNPs/GPONPs/PGE). GKNPs/GPONPs/PGE worked in optimum conditions of pH 7.0, temperature 30 °C, at an applied potential of -0.3 V. The biosensor exhibited wide linear response in a concentration range of glycerol (0.01-45 mM) with detection limit 0.0001 µM. The biosensor revealed high sensitivity (7.24 µAmM-1cm-2), low response time (2.5s) and a good agreement with the standard enzymic colorimetric method with a correlation coefficient (R2 = 0.99). The evaluation study of biosensor offered a good analytical recovery of 98.73% when glycerol concentration was added to the sera sample. In addition, within and between batches study of working electrode showed coefficients of variation as 0.105% and 0.14%, respectively. The application of biosensor is performed in the serum of apparently healthy subject and patients affected by cardiogenic shock. There was a 20% loss in initial activity of biosensor after its regular use over a time period of 180 days, while being stored at 4 °C.

Detection of chikungunya virus DNA using two-dimensional MoS2 nanosheets based disposable biosensor.

Development of platforms for a reliable, rapid, sensitive and selective detection of chikungunya virus (CHIGV) is the need of the hour in developing countries. To the best of our knowledge, there are no reports available for the electrochemical detection of CHIGVDNA. Therefore, we aim at developing a biosensor based on molybdenum disulphide nanosheets (MoS2 NSs) for the point-of-care diagnosis of CHIGV. Briefly, MoS2 NSs were synthesized by chemical route and characterized using scanning electron microscopy, transmission electron microscopy, UV-Vis spectroscopy, Raman spectroscopy and X-Ray Diffraction. MoS2 NSs were then subjected to physical adsorption onto the screen printed gold electrodes (SPGEs) and then employed for the detection of CHIGV DNA using electrochemical voltammetric techniques. Herein, the role of MoS2 NSs is to provide biocompatibility to the biological recognition element on the surface of the screen printed electrodes. The detection strategy employed herein is the ability of methylene blue to interact differentially with the guanine bases of the single and double-stranded DNA which leads to change in the magnitude of the voltammetric signal. The proposed genosensor exhibited a wide linear range of 0.1 nM to 100 µM towards the chikungunya virus DNA.