An innovative transportable immune device for the recognition of α-synuclein using KCC-1-nPr-CS2 modified silver nano-ink: integration of pen-on-paper technology with biosensing toward early-stage diagnosis of Parkinson's disease.

Parkinson's disease (PD), the second most frequent neurodegenerative illness, is a neurological ailment that produces unintentional or uncontrolled body movements, which should be diagnosed in its early stages to hinder the progression. Monitoring the concentration of α-synuclein (α-Syn) in body fluids can be one of the most efficient ways for PD early detection. In this work, a paper-based electrochemical immunosensor was designed for α-Syn bio-assay in human plasma samples based on encapsulation of the biotinylated antibody on novel dendritic fibrous nanosilica ((KCC-1-nPr-CS2)-Ab). For this purpose, a three-electrode system was prepared using stabilization of silver nano-ink on photographic paper. Then, the (KCC-1-NH-CS2)-Ab was immobilized on its surface and used to detect the target antigen (α-Syn). After characterization of the prepared substrate by FE-SEM and EDS, the redox behavior of the biosensor was evaluated using chronoamperometry techniques. Under optimal experimental conditions and using a label-free strategy, the engineered immunosensor showed a linear relationship between peak current and antigen concentration in the linear range from 0.002 to 128 ng mL-1 with the lower limit of quantification of 0.002 ng mL-1. Moreover, this work involves unprecedented use of conductive nano-inks for the manufacture of α-Syn immunosensor, which is aided by the use of a mesoporous silicate dendrimer in encapsulating the α-Syn antibody, thus offering a robust and simple point-of-care device for early PD diagnosis. The ability of the proposed platform to detect small amounts of α-Syn offers a promising approach to developing low-cost, sensitive, and transportable biosensors for Parkinson's disease screening in its early stages.

Microfluidic paper-based colorimetric quantification of malondialdehyde using silver nanoprism toward on-site biomedical analysis: a new platform for the chemical sensing and biosensing of oxidative stress.

Malondialdehyde (MDA) is a critical product of polyunsaturated adipose acid peroxidation and represents a common biomarker of oxidative stress. The effect of different MDA concentrations on human biofluids reflects pathological changes, which has been seen in diverse types of sickness, such as leukemia, diabetes, cancer, cardiovascular disease, and age-related macular degeneration and liver disease. In this study, different types of silver nanoparticles, including silver nanoprism (AgNPrs), silver nanowires (AgNWs), and silver nanospheres (AgNSs), were synthesized and used for the chemosensing of MDA by colorimetric and spectrophotometric methods. Colorimetric tests were performed to identify malondialdehyde in the solution as well as the one-droplet-based microfluidic paper substrate as a miniaturization device for the monitoring of analytes in human real samples. The analytical quantification of the MDA was done using the UV-Vis method. Also, the utilization of the designed chemosensor for the analysis of MDA in real sample was evaluated in human urine samples. Using the spectrophotometric method, MDA was deformed in the linear range of 0.01192 to 1.192 mM with a low limit of quantification of 0.12 µM. Essential significant features of this study include the first application of AgNPrs with high stability and great optical properties without any reagent as an optical sensing probe of MDA and optimized OD-µPCD toward on-site and on-demand MDA screening in real samples diagnosis and the innovative time/color semi-analytical recognition strategy. Moreover, the prepared OD-µPCD decorated by AgNPrs could be a prized candidate for commercialization due to the benefits of the low-cost materials used, like paper and paraffin, and portability. This innovative process led to uniform hydrophilic micro-channels on the surface of cellulose, without the use of a UV lamp, clean room, and organic solvents. This report could be a pioneering work, inspiring simple and effective on-site semi-analytical recognition devices for harmful substances or illegal drugs, which simply consist of a piece of lightweight paper and one drop of the required reagent.

Multifunctional one-droplet microfluidic chemosensing of ractopamine in real samples: a user-oriented flexible nano-architecture for on-site food and pharmaceutical analysis using optical sensors.

Illegal use of ractopamine (RAC) in the food industry has dire consequences for health which should be curbed by inexpensive on-site checks. In this study, four advanced nanostructures of AuNPs were examined for this purpose. For the first time, a novel cost-effective colorimetric opto-sensor based on gold nanoparticles in aqueous solution was developed and successfully utilized for the recognition of RAC in real samples. The colorimetric chemosensor based on AuNPs-CysA exhibited a linear range of 0.1 µM to 0.01 M with a limit of detection (LOD) of 0.001 µM. Also, using AuNPs-DDT as a photonic probe two ranges of linearity of 0.01 to 50 µM and 0.005 to 0.01 M were obtained (LOD = 1 nM). The outstanding features of the utilized nanostructures are the simple preparation, the suitable stability of AuNPs-CysA and the excellent selectivity of AuNPs-DDT toward RAC recognition. Finally, the engineered colorimetric systems were combined with a simple and inexpensive optimized microfluidic glass fiber-based device. This work paves the way for devising inexpensive and efficient on-site recognition devices for food safety checks.

Construction of a hydrophobic-hydrophilic open-droplet microfluidic chemosensor towards colorimetric/spectrophotometric recognition of quetiapine fumarate: a cost-benefit method for biomedical analysis using a smartphone.

Quetiapine fumarate (QF) is used to treat a number of mental/emotional diseases, including schizophrenia, bipolar disorder, and abrupt bouts of mania or depression linked to bipolar disorder. This antipsychotic medicine can be deadly if an overdose is given to a person. Therefore, the sensitive identification of QF in bodily fluids is very important. In this study, an innovative low-cost colorimetric chemosensor based on silver nanoprism transfiguration in a phosphate-buffered saline (PBS)/Cl- matrix was developed and successfully tested for the recognition of QF in human-exhaled breath condensate. Using this non-invasive colorimetric chemosensor, a broad linearity range of 0.001-1000 µM and a low limit of quantification of 0.001 µM for QF were attained. Notably, the proposed optical chemosensor is capable of detecting QF from a minimum amount of sample [500 µM in PBS and 0.001 µM in exhaled breath condensate] in the first few seconds of reaction by the naked eye. So, a rapid colorimetric assay for the on-site analysis of QF was developed and validated. Moreover, for the first time, a semi-analytical method was introduced that can provide a rough estimation of the QF concentration. This colorimetric system was, for the first time, integrated in an optimized microfluidic paper-based colorimetric device (µPCD), promising the development of an engineered colorimetric opto-sensor toward real-time and therapeutic drug monitoring (TDM) assay of drugs in real-world samples.

A portable colorimetric chemosensing regime for ractopamine in chicken samples using µPCD decorated by silver nanoprisms.

In recent years the use of ractopamine (RAC), originally synthesized for the treatment of respiratory diseases, is on the rise as a dietary supplement in animals. The excessive use of RAC has some adverse effects on human health. Hence, the demand for simple, easy-to-use, and expendable devices for RAC recognition, even in remote areas, is felt more than ever before. This need prompted us to devise a straightforward colorimetric system for RAC recognition based on the etching effect of RAC on AgNPrs. This nanoprobe is a very advanced materials with great optical properties and stability, which could be used unprecedentedly without any combination or reagents for RAC recognition. Considering the needs and advantages, a simple colorimetric chemosensor for the quantification of RAC was designed and applied to a chicken sample. The designed chemosensor was integrated with an optimized microfluidic paper-based colorimetric device (µPCD), creating a suitable tool for the determination of RAC based on a time/color pattern. The analytical metrics for this simple colorimetric chemosensing regime comprise a best colorimetric LLOQ of 100 µM in solution with 10 µM of µPCD, a spectroscopic LLOQ of 10 nM, and a broad linearity range of 0.1-10 000 µM, which are outstanding compared with other colorimetric techniques. The main remarkable features of this study include the first utilization of AgNPrs with high stability and excellent optical properties without any reagent as an optical sensing probe and optimized µPCD toward RAC recognition and the innovative time/color semi-analytical recognition method. Moreover, the prepared portable µPCD modified with AgNPrs could be a prized candidate for commercialization due to the benefits of the low-cost materials used, like paper and paraffin, and the simple instructions for µPCD preparation. This report could be a pioneering work, inspiring simple and effective on-site semi-analytical recognition devices for harmful substances or illegal drugs, which simply consist of a piece of lightweight paper and one drop of the required reagent.

Aptamer-based assay for monitoring genetic disorder phenylketonuria (PKU).

The genetic disorder phenylketonuria (PKU) is the inability to metabolize phenylalanine because of a lack of the enzyme phenylalanine hydroxylase. Phenylalanine is used to biochemically form proteins, coded for by DNA. The development of an apta-assay for detection of l-Phenylalanine is presented in this work. A highly specific DNA-aptamer, selected to l-Phenylalanine was immobilized onto a gold nanostructure and electrochemical measurements were performed in a solution containing the phosphate buffer solution with physiological pH. We have constructed an aptamer immobilized gold nanostructure mediated, ultrasensitive electrochemical biosensor (Apt/AuNSs/Au electrode) for l-Phenylalanine detection without any additional signal amplification strategy. The aptamer assemble onto the AuNSs makes Apt/AuNSs/Au electrode an excellent platform for the l-Phenylalanine detection in physiological like condition. Differential pulse voltammetry were used for the quantitative l-Phenylalanine detection. The Apt/AuNSs/Au electrode offers an ultrasensitive and selective detection of l-Phenylalanine down to 0.23 µM level with a wide dynamic range from 0.72 µM-6 mM. The aptasensor exhibited excellent selectivity and stability. The real sample analysis was performed by spiking the unprocessed human serum samples with various concentration of l-Phenylalanine and obtained recovery within 2% error value. The sensor is found to be more sensitive than most of the literature reports. The simple and easy way of construction of this apta-assay provides an efficient and promising diagnosis of phenylketonuria.

Ultrasensitive electrochemical immunosensing of tumor suppressor protein p53 in unprocessed human plasma and cell lysates using a novel nanocomposite based on poly-cysteine/graphene quantum dots/gold nanoparticle.

An ultrasensitive electrochemical immunosensor for quantitation of tumor suppressor protein p53 based on ternary signal amplification strategy was fabricated. In this work, p53-antibody was immobilized onto a green and biocompatible nanocomposite containing poly l-cysteine (P-Cys) as conductive matrix and graphene quantum dots (GQDs)/gold nanoparticles (GNPs) as dual amplification elements. Therefore, a novel multilayer film based on P-Cys, GQDs, and GNPs was exploited to develop a highly sensitive immunosensor for detection of p53. Fully electrochemical methodology was used to prepare a new transducer on a gold surface which provided a high surface area to immobilize a high amount of the anti-p53. Under optimized condition the calibration curve for p53 concentration was linear up to 0.000197-0.016 pM (by SWV technique) and 0.195-50 pM (by DPV technique) with lower limit of quantification of 0.065 fM. Also, linear range and lower limit of quantification of p53 in unprocessed human plasma were 0.000592-1.296 pM and 0.065 fM, respectively. The method was applied to the assay of p53 in human plasma sample and normal and malignant cell line lysates such as normal cell Line from mouse C3H (L929), colon cancer cell-HCT, prostate cancer cell line PC-3, and human breast adenocarcinoma cell line-MCF7.

An innovative immunosensor for detection of tumor suppressor protein p53 in unprocessed human plasma and cancer cell lysates.

An innovative mediator-free electrochemical immunosensor for quantitation of p53 tumor suppressor protein based on signal amplification strategy was fabricated. In this work, biotin conjugated p53-antibody (anti-p53) was immobilized onto a green and biocompatible nanocomposite containing poly l-cysteine (P-Cys) as conductive matrix and 3D gold nanoparticles (GNPs) as signal amplification element. Therefore, a novel nanocomposite film based on P-Cys and GNPs was exploited to develop a highly sensitive immunosensor for detection of p53 protein. Importantly, GNPs prepared by sonoelectrodeposition method which lead to compact morphology. Fully electrochemical methodology was used to prepare a new transducer on a gold surface which provided a high surface area to immobilize a high amount of the anti-p53. The surface morphology of electrode was characterized by high-resolution field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDX). The immunosensor was employed for the detection of p53 in physiological pH using square wav voltammetry and differential pulse voltammetry (DPVs) techniques. Under optimized condition the calibration curve for p53 concentration by SWV and DPV was linear in 0.0369-50pM and 0.018-2.5pM with lower limit of quantification of 48fM and 18fM, respectively. The method was successfully applied assay of the p53 in unprocessed human plasma samples. Also, the method was applied to the assay of p53 in human plasma sample and normal and malignant cell line lysates such as (L929 normal cell Line from mouse C3H (L929), colon cancer cell-HCT, prostate cancer cell line PC-3, and human breast adenocarcinoma cell line-MCF7).