Identification of acetaldehyde based on plasmonic patterns of a gold nanostructure conjugated with chromophore and H2O2: a new platform for the rapid and low-cost analysis of carcinogenic agents by colorimetric affordable test strip (CATS).

Acetaldehyde, a prevalent carbonyl compound in fermented foods, poses challenges in various applications due to its reactivity. This study addresses the need for efficient acetaldehyde detection methods across biotechnological, environmental, pharmaceutical, and food sectors. Herein, we present a novel colorimetric/UV spectrophotometric approach utilizing gold nanoparticles (AuNPs), particularly gold nano-flowers (AuNFs), for sensitive acetaldehyde identification. The method exhibits a notable sensitivity, detecting acetaldehyde at concentrations as low as 0.1 µM. The mechanism involves the interaction of acetaldehyde molecules with AuNFs, leading to a significant change in the absorbance spectrum, which serves as the basis for detection. Moreover, its applicability extends to human biofluids, notably urine samples. Integration with a cost-effective one-drop microfluidic colorimetric device (OD-µPCD) enables the development of an affordable test strip (CATS). This semi-analytical device, employing a multichannel OD-µPCD, facilitates real-time analysis of acetaldehyde in human samples. Our findings demonstrate the pioneering utilization of AuNPs for selective and sensitive acetaldehyde detection, promising advancements in environmental and occupational safety standards, and laying a foundation for enhanced detection and monitoring of related volatile organic compounds (VOCs).

Optimization of a silver-nanoprism conjugated with 3,3',5,5'-tetramethylbenzidine towards easy-to-make colorimetric analysis of acetaldehyde: a new platform towards rapid analysis of carcinogenic agents and environmental technology.

Acetaldehyde acts as an important mediator in the metabolism of plants and animals; however, its abnormal level can cause problems in biological processes. Although acetaldehyde is found naturally in many organisms, exposure to high concentrations can have effects on the eyes, respiratory system, etc. Due to the importance of detecting acetaldehyde in environmental samples and biofluids, determination of its concentration is highly demanded. There are some reports showing exposure to high concentrations of acetaldehyde for a long time can increase the risk of cancer by reacting with DNA. In this work, we presented a novel colorimetric method for rapid and sensitive detection of acetaldehyde with high reproducibility using different AgNPs with various morphologies. The redox reaction between AgNPs, 3,3',5,5'-tetramethylbenzidine (TMB) solution, and analytes endows a color change in 15 minutes that is detectable by the naked eye. UV spectrophotometry was further used for quantitative analysis. An iron mold with a hexagonal pattern and liquid paraffin were also used to prepare the paper-based microfluidic substrate, as a low cost, accessible, and rapid detection tool. Different types of AgNPs showed different lower limits of quantification (LLOQ). The AgNPs-Cit and AgNPrs could identify acetaldehyde with linear range of 10-7 to 10 M and an LLOQ of 10-7 M. The AgNWs showed the best color change activity with a linear range 10-5 to 10 M and the lowest diagnostic limit is 10-5 M. Finally, analysis of human biofluids as real samples were successfully performed using this system.

Colorimetric and naked-eye detection of arsenic(iii) using a paper-based microfluidic device decorated with silver nanoparticles.

Arsenic (As) as a metal ion has long-term toxicity and its presence in water poses a serious threat to the environment and human health. So, rapid and accurate recognition of traces of As is of particular importance in environmental and natural resources. In this study, a fast and sensitive colorimetric method was developed using silver nano prisms (Ag NPrs), cysteine-capped Ag NPrs, and methionine-capped Ag NPrs for accurate detection of arsenic-based on transforming the morphology of silver nanoparticles (AgNPs). The generated Ag atoms from the redox reaction of silver nitrate and As(iii) were deposited on the surface of Ag NPrs and their morphology changed to a circle. The morphological changes resulted in a change in the color of the nanoparticles from blue to purple, which was detectable by the naked eye. The rate of change was proportional to the concentration of arsenic. The changes were also confirmed using UV-Vis absorption spectra and showed a linear relationship between the change in adsorption peak and the concentration of arsenic in the range of 0.0005 to 1 ppm with a lower limit of quantification (LLOQ) of 0.0005 ppm. The proposed probes were successfully used to determine the amount of As(iii) in human urine samples. In addition, modified microfluidic substrates were fabricated with Ag NPrs, Cys-capped Ag NPrs, and methionine-capped Ag NPrs nanoparticles that are capable of arsenic detection in the long-time and can be used in the development of on-site As(iii) detection kits. In addition, silver nanowires (AgNWs) were used as a probe to detect arsenic, but good results were not obtained in human urine specimens and paper microfluidic platforms. In this study, for the first time, AgNPs were developed for optical colorimetric detection of arsenic using paper-based microfluidics. Ag NPrs performed best in both optical and colorimetric techniques. Therefore, they can be a promising option for the development of sensitive, inexpensive, and portable tools in the environmental and biomedical diagnosis of As(iii).

Sensitive recognition of prostate-specific antigen using biotinylated antibody encapsulated on D-penicillamine decorated wrinkled silicate nanoparticles (WSN): An innovative sandwich-type biosensor toward diagnosis of prostate cancer.

In this study, a new sandwich-type biosensor was developed to specific recognition of prostate-specific antigen (PSA) and early-stage diagnosis of prostate cancer using encapsulation of biotinylated antibody (Ab1) of prostate-specific antigen on D-penicillamine decorated wrinkled silicate nanoparticles (WSN). For the first time, KCC-1-NH-DPA was synthesized and used to immobilization of biomacromolecules. So, fabricated immunosensor was performed by on sandwich-type strategy. After fabrication of immunosensor, cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry techniques were used to electrochemical evaluation of immune-platform for PSA detection. The proposed biocompatibility immune-platform provided a novel interface toward sensitive bioanalysis of PSA biomarker in human plasma samples. Due to the use of gold nanoparticles functionalized Cysteamine (Cys A) in the structure of the secondary antibody (Ab2 [HRP-Ab2]), the intensity of the electrochemical signal has increased, resulting in a more accurate detection of the target molecules. Under the right conditions, the engineering immunosensor provides good bioanalytical performance for determining the PSA biomarker in the linear range of 0.002 to 60 µg L-1 which low limit of quantification was 0.002 µg L-1 . As a result, it is suggested to use these immune-devices in the clinical pre-diagnosis of prostate cancer.

Electrochemical immunoplatform to assist in the diagnosis of oral cancer through the determination of CYFRA 21.1 biomarker in human saliva samples: Preparation of a novel portable biosensor toward non-invasive diagnosis of oral cancer.

In this study, a novel, low-cost, and flexible paper-based electrochemical immunosensor was developed for the bioanalysis of Cyfra 21.1 biomarker in human saliva samples by using stabilization of synthesis Ag nano-ink on the surface of paper using pen-on-paper technology. The employed electrochemical techniques for the evaluation of immunoplatform performance were differential pulse voltammetry and chronoamperometry. Also, the prepared immunosensor showed great ability in the determination of Cyfra21.1 in human saliva specimens. Under the optimized conditions, the obtained linear range was from 0.0025 to 10 ng/mL, and the obtained LLOQ was 0.0025 ng/mL. The developed immunosensor is easy to prepare, sensitive, cost-effective, portable, and simple. So proposed immunoplatform can be an accomplished biodevice in clinical laboratories. The proposed paper-based immunosensor could be a hopefully new and cheap tool for the diagnosis of other biomarkers. Also, the prepared immunosensor showed great ability in the determination of Cyfra21.1 biomarker in human saliva specimens.

A microfluidic paper-based colorimetric device for the visual detection of uric acid in human urine samples.

The monitoring of uric acid (UA) as a clinically relevant toxic biomolecule is of particular importance for the diagnosis of various syndromes and for the monitoring of patients undergoing chemotherapy or radiation therapy. Owing to its speed, low consumption of materials, high sensitivity, convenience, and the easy detection of color changes, colorimetric methods have attracted a lot of attention compared to other methods. The use of nanoparticles has been suggested for the non-enzymatic POC detection of biological molecules such as UA. Here, a sensitive, quantitative, and rapid diagnostic method for UA using silver nanoparticles (AgNPs) is reported. The main purpose of this work is to introduce a suitable tool for future studies based on various types of AgNPs for the on-site detection of clinical samples and biomarkers using portable devices. In the present study, a novel µPCD made to measure UA was used in human urine samples. AgNPs with their peroxidase-like activity led to the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) and a bluish-green color upon the decomposition of hydrogen peroxide to ˙OH. UA also reduced the oxidized TMB. The proposed method showed linear responses from 500 to 10 000 µM (using silver citrate nanoparticles (Ag-Cit)), 50 to 10 000 µM (using Ag NPrs and Au@AgNPs), and 1 to 10 000 µM (using Ag NWs). The lower limits of quantification of the proposed method for the detection of UA using Ag-Cit, Ag nanoprisms, Au@Ag core-shell nanoparticles, and Ag nanowires were 500, 50, 50, and 1 µM, respectively. As a result, the proposed assay system could potentially be utilized to detect UA in human urine samples.

Flexible paper-based label-free electrochemical biosensor for the monitoring of miRNA-21 using core-shell Ag@Au/GQD nano-ink: a new platform for the accurate and rapid analysis by low cost lab-on-paper technology.

miRNA-21 is one of the most famous and prominent microRNAs that is important in the development and emergence of cancers. So, the sensitive and selective monitoring of miRNA-21 as a very common biomarker in cancer treatment is necessary. In this work, a novel paper-based electrochemical peptide nucleic acid (PNA) sensor was developed for the detection of miRNA-21 in human plasma samples by using Ag@Au core-shell nanoparticles electrodeposited on graphene quantum dots (GQD) conductive nano-ink (Ag@Au core-shell/GQD nano-ink), which was designed directly by writing pen-on paper technology on the surface of photographic paper. This nano-ink has a great surface area for biomarker immobilization. The prepared paper-based biosensor is very small and cheap, and also has high stability and sensitivity. Hybridization of PNA was measured using various electrochemical techniques, such as cyclic voltammetry (CV), square wave voltammetry (SWV) and chronoamperometry (ChA). FE-SEM (Field Scanning Electron Microscope), TEM (Transmission Electron Microscope), EDS and DLS (Dynamic Light Scattering) tests were performed to identify the engineering safety sensor. Under optimal conditions, the linear range for the calibration curve was from 5 pM to 5 µM, and the achieved LLOQ was 5 pM. The obtained results recommended that the proposed bioassay might be suitable for an early diagnosis of cancer based on the inhibition of the expression of miRNA-21, which activates the enzyme caspase and accelerates apoptotic proteins and death in tumor cells.

Microfluidic biosensing of circulating tumor cells (CTCs): Recent progress and challenges in efficient diagnosis of cancer.

Cancer metastasis is one of the foremost causes of cancer incidence and fatality in the whole of the world. Circulating tumor cells (CTC) have been confirmed to be among the most significant stimuli of metastasis in recent years and presently are the subject of extensive research aiming to be accurately identified by using biological and physical properties. Among the various studies conducted for isolation, identification, and characterization of CTCs, microfluidic systems have aroused great attention owing to their unique advantages such as low-cost, simplicity, reduction in reagent consumption, miniaturization, fast and precise control. The purpose of this review is to provide an overview of current state of the microfluidic biosensors for the screening of CTCs. Additionally, given the recent progress in this field, future outlook for the development of the microfluidics biosensing is briefly discussed.

Architecture of a multi-channel and easy-to-make microfluidic paper-based colorimetric device (µPCD) towards selective and sensitive recognition of uric acid by AuNPs: an innovative portable tool for the rapid and low-cost identification of clinically relevant biomolecules.

Uric acid (UA) is the end product of purine metabolism. Uric acid is usually excreted in the urine, but its abnormal increase and toxic amount can lead to diseases such as gout, hyperuricemia, Lesch-Nyhan syndrome, and cardiovascular disease. On the other hand, UA reduction can lead to neurodegenerative diseases such as sarcoma, glioblastoma, Hodgkin, and etc. Therefore, rapid identification of UA is of great importance. In this work, a simple, portable, inexpensive, and fast microfluidic paper-based colorimetric sensor based on the color change in the presence of UA by using AuNPs was developed. The results can be easily identified with naked eye and further confirmed by UV-vis spectrophotometry. In this method, iron pattern and fiberglass paper were used to construct diagnostic areas and hydrophilic microfluidic channels. We greatly reduced the preparation time of this pattern using a magnet (about three minutes). In this work, four types of nanoparticles with different lower limit of quantification (LLOQ) were used. Linear range of 10-6 to 10-3 M and LLOQ of 10-6 M were obtained for the determination of uric acid using AuNPs-CysA as optical probe. Also, by AuNPs as optical probe a linear range of 10-4 to 10-2 M and the obtained LLOQ was 10-4 M. Finally, by AuNFs as optical probe linear range from 10-6 to 10-2 M and 5 × 10-5 to 10-2 M along with LLOQ of 10-6 and 5 × 10-5 M, respectively. The designed system successfully studied in human urine samples.

Nanomaterial based aptasensing of prostate specific antigen (PSA): Recent progress and challenges in efficient diagnosis of prostate cancer using biomedicine.

Cancer is known to be one of the most major issues all around the world and is the most important cause of death. Prostate cancer is one of the most prevalent cancers among men, and the principal reason of death due to this cancer is the inappropriate detecting tools. Therefore, there is a great request for accurate diagnosis of prostate-specific antigen (PSA). Bio-analysis based on biomarkers might help to overcome this problem. Aptamers can be employed as high-affinity tools for cancer detection. The utilization of aptamer-based strategy in cancer investigation has demonstrated new horizons in biotechnology. The use of nanotechnology in biosensing is a serious development in this field. Advanced nanomaterials enhance the signal amplification in the biosensors, which also reduce the time required for diagnosis and analysis, they are also affordable, with high accuracy. In the present review (with 108 references), we discussed excellent features of the aptasensors on the sensitive and accurate monitoring of PSA biomarkers. Moreover, various types of nanomaterial-based aptasensors were surveyed for PSA detection (electrochemical, optical, piezoelectric, photoelectrochemical, electrochemiluminescent, and so forth). Furthermore, we reported the role of advanced nanomaterials, for instance graphene oxide, carbine nanotube, quantum dots, silica, gold, silver, and magnetic nanoparticles on the improvement of aptasensors of PSA. Finally, we discussed the advantages and limitations of different strategies on the early stage diagnosis of cancer. This article has been updated until July 2020.

Optimized DNA-based biosensor for monitoring Leishmania infantum in human plasma samples using biomacromolecular interaction: a novel platform for infectious disease diagnosis.

Leishmania parasite identification is very important in clinical studies of leishmaniasis and its diagnosis. Though there are various clinical and epidemiological approaches to identifying Leishmania infantum, due to some limitations of the traditional methods, sensitive and specific techniques are needed and are in great demand. To achieve selective and rapid detection, a sensitive signal transducer with high surface area is necessary. In this work, a new paper sensor was fabricated using silver nanoprisms electrodeposited on the GQD conductive nano-ink (Ag NPr/GQDs nano-ink). A high surface area and suitable interface for anchoring biomolecules was achieved by electrodepositing gold nanoparticles (AuNPs) functionalized with cysteamine (AuNPs-CysA) on the surface of the paper sensor altered by Ag NPr/GQDs nano-ink. To prepare a sensitive and selective bio-device for the recognition of Leishmania in human plasma specimens, a DNA-thiol probe was stabilized on the surface of the platform. Hybridization of DNA was evaluated by chronoamperometry (ChA). The engineered DNA-based paper biosensor showed high sensitivity and selectivity for the identification of Leishmania genomic DNA. Under optimum circumstances, a linear range was obtained using photographic paper from 1 µM to 1 zM and an ivory sheet from 1 nM to 1 zM. The lower limits of quantitation (LLOQ) on the photographic paper and ivory sheet were 1 zM. In addition, the designed DNA-based biosensor revealed well-defined performance in the recognition of mismatched sequences (single base, two base and three base mismatches) and selectivity.

A novel bioassay for the monitoring of carcinoembryonic antigen in human biofluid using polymeric interface and immunosensing method.

Carcinoembryonic antigen (CEA) is a member of a family of cell surface glycoproteins. Recognition of CEA is needed to monitor the physiological status of the patient for treatment and also it is important to assess the severity of the disease. In this work, we reported a novel sandwich-type electrochemical immunosensor based on gold nanoparticles functionalized cysteamine-glutaraldehyde (AuNPs-CysA-GA) and it successfully designed to detection of the CEA biomarker in a human plasma sample. The AuNPs-CysA-GA provides a large surface area for the effective immobilization of CEA antibody, as well as it ascertains the bioactivity and stability of immobilized CEA antigens. Biotinylated-anti-CEA antibody (Ab1) was immobilized on the surface of glassy carbon electrode (GCE) modified AuNPs-CysA-GA. Also, secondary antibody (HRP-Ab2) was costed immobilized to complete the sandwich part of immunosensor. Field emission scanning electron microscope (FE-SEM and EDS), was employed to monitor the sensor fabrication procedure. The immunosensor was used for the detection of CEA using differential pulse voltammetry (DPVs) technique. The proposed interface led to enhancement of accessible surface area for immobilizing high amount of anti-CEA antibody, increasing electrical conductivity, boosting stability, and biocompatibility. Finally, the low limit of quantitation (LLOQ) of the proposed immunosensor was obtained as 7 ng/mL with the linear range of 0.001-5 µg/L. The proposed immunoassay was successfully applied for the monitoring of the CEA in unprocessed human plasma samples. Obtained results paved that the proposed bioassay can be used as a novel bioassay for the clinical diagnosis of cancer based on CEA monitoring.

A novel electroconductive interface based on Fe3 O4 magnetic nanoparticle and cysteamine functionalized AuNPs: Preparation and application as signal amplification element to minoring of antigen-antibody immunocomplex and biosensing of prostate cancer.

In this study, a novel electroconductive interface was prepared based on Fe3 O4 magnetic nanoparticle and cysteamine functionalized gold nanoparticle. The engineered interface was used as signal amplification substrate in the electrochemical analysis of antibody-antigen binding. For this purpose, biotinilated-anti-prostate-specific antigen (PSA) antibody was bioconjugated with iron oxide magnetic nanoparticles (Fe3 O4 ) and drop-casted on the surface of glassy carbon electrode (GCE). Also, secondary antibody (HRP-Ab2) encapsulated on gold nanoparticles caped by cysteamine was immobilized on the surface of GCE modified electrode. A transmission electron microscopy images shows that a sandwich immunoreaction was done and binding of Ab1 and Ab2 performed successfully. Various parameters of immunoassay, including the loading of magnetic nanoparticles, the amount of gold nanoparticle conjugate, and the immunoreaction time, were optimized. The detection limit of 0.001 µg. L-1 of PSA was obtained under optimum experimental conditions. It is found that such magneto-bioassay could be readily used for simultaneous parallel detection of multiple proteins by using multiple inorganic metal nanoparticle tracers and are expected to open new opportunities for early stage diagnosis of cancer in near future.