Bio: Anas Saifi is an academic researcher from Delhi Technological University. The author has contributed to research in topics: Visible spectrum & PEDOT:PSS. The author has an hindex of 1, co-authored 2 publications receiving 45 citations.
TL;DR: The proposed immunoelectrode was validated with conventional ELISA for the detection of CEA in serum samples of cancer patients and resulted in improved electrochemical performance and signal stability.
Abstract: We report results of the studies relating to the fabrication of a label-free, flexible, light weight and disposable conducting paper based immunosensing platform comprising of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and nanostructured iron oxide (nFe(2)O(3)@PEDOT:PSS) nanocomposite for detection of carcinoembryonic antigen (CEA), a cancer biomarker. The effect of various solvents such as sorbitol, ethanol, propanol, n-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) on the electrical conductivity of Whatman filter paper (WP) modified with nFe(2)O(3)@PEDOT:PSS/WP was investigated. The electrical conductivity of the PEDOT:PSS/WP electrode was found to be enhanced by two orders of magnitude (from 6.8 x 10(-4) to 1.92 x 10(-2) Scm(-1)) after its treatment with DMSO. Further, nFe(2)O(3) doped PEDOT:PSS/WP electrode exhibited the electrical conductivity as 2.4 x 10(-2) Scm(-1). Besides this, the incorporation of iron oxide nanoparticles (nFe(2)O(3)) into PEDOT:PSS/ WP resulted in improved electrochemical performance and signal stability. This nFe(2)O(3)@ PEDOT:PSS/WP based platform was used for immobilization of the anti-carcinoembronic antigen (anti-CEA) protein for quantitative estimation of cancer biomarker (CEA). The results of electrochemical response studies revealed that this conducting paper based immunoelectrode had a sensitivity of 10.2 mu Ang(-1) mLcm(-2) in the physiological range (4-25 ngmL(-1)) and shelf life of 34 days. Further, the proposed immunoelectrode was validated with conventional ELISA for the detection of CEA in serum samples of cancer patients. (C) 2019 Elsevier B.V. All rights reserved.
TL;DR: In this paper , a review examines the current trends and challenges in designing and applying carbon nanostructure-based optical sensors for detecting aquatic contaminants, including pesticides, bacterial pathogens, and pharmaceuticals residues.
Abstract: In recent years, optical sensing based on nanomaterials has emerged as a prospective strategy for monitoring environmental pollution in water. In this context, carbon nanostructures have received increasing attention due to their unique optoelectronic and physiochemical properties. To this end, nanocarbon such as carbon nanotubes, graphene, and carbon dots have been used to develop proof-of-concept opto-chemical sensors for emerging aquatic contaminants, including pesticides, bacterial pathogens, and pharmaceuticals residues. These optical sensors have attracted significant research interest in nanotechnology, material science, and the detection of aquatic pollutants. However, the practical application for detecting contaminants is still limited because of cost-effectiveness, sensitivities, and selectivity toward the diverse pollutants. This review examines the current trends and challenges in designing and applying carbon nanostructure-based optical sensors for detecting aquatic contaminants. Finally, a critical perspective on the field and future research directions is provided.
TL;DR: In this article , a supramolecular strategy is used for the synthesis of a functionalized anthracene dye which absorbs light in the visible region due to red-shift in the absorption band.
Abstract: Light-responsive soft actuators are highly demanded due to their increasing applications in soft robotics and biomimetic devices. However, for light-driven soft actuators, it is challenging to eliminate their reliance on UV light as well as it is required to address the issue of poor mechanical strength. Here, a supramolecular strategy is used for the synthesis of a functionalized anthracene dye which absorbs light in the visible region due to red-shift in the absorption band. This photoresponsive functionalized anthracene dye, mixed in the PVA matrix, has been used as a soft actuator acting as a microgripper to grasp, pick up, and transport cargo in response to the blue light. As a new finding, a two-fold increase in the bending angle deformation was achieved which is significantly greater than any other previously reported anthracene-based visible light-responsive soft actuator. This work broadens the horizon of the natural light-responsive soft actuators which may find applications in soft robotics, biomimetic grippers, surgical instruments, etc.
TL;DR: The progress in functionalization of cellulose papers with antibodies, nucleic acids and nanomaterials in PBBs and μPADs, is discussed and critically evaluated.
Abstract: A remarkable progress in the development of portable paper-based biosensors (PBBs) and microfluidic paper-based analytical devices (μPADs) has recently been achieved. In these devices, a paper formed of microfibers of cellulose, a carbohydrate biopolymer, offers both an ample space in its micropores for analytical reagents storage and a capillary force to drive liquid samples to a dedicated reaction zone for instantaneous detection of the desired analytes. Owing to the low cost and ultra-high sensitivity, these novel devices have become a promising alternative to traditional advanced analytical instruments and offer great potential for applications in medical emergencies, health diagnostics at points-of-care, and broad early-cancer screening. In this review, we focus particularly on recent important achievements in utilization of cellulose and its modifications in portable sensing devices for biomedical applications. The progress in functionalization of cellulose papers with antibodies, nucleic acids and nanomaterials in PBBs and μPADs, is discussed and critically evaluated.
TL;DR: An ultrasensitive SPR biosensor for detecting carcinoembryonic antigen (CEA) in real serum samples is described, providing a promising method to evaluate CEA in human serum for early diagnosis and monitoring of cancer.
Abstract: Surface plasmon resonance (SPR) has become a leading technique for in situ bioaffinity assay of diverse targets without need of fluorescent or enzymatic labeling. Nanomaterials-enhanced SPR sensors have developed rapidly and widened the application scope of SPR sensing technology. In this report we describe an ultrasensitive SPR biosensor for detecting carcinoembryonic antigen (CEA). Our SPR biosensor utilizes a Ti3C2-MXene-based sensing platform and multi-walled carbon nanotube (MWCNTs)-polydopamine (PDA)-Ag nanoparticle (AgNPs) signal enhancer. Ti3C2-MXene, a new class of two-dimensional (2D) transition metal carbides, offers a large hydrophilic-biocompatible surface ideal for SPR biosensing. Ti3C2-MXene/AuNPs composites after synthesis are then decorated with staphylococcal protein A (SPA) to orient and immobilize monoclonal anti-CEA antibody (Ab1) through its Fc region. By introducing MWCNTs-PDA-AgNPs-polyclonal anti-CEA antibody (MWPAg-Ab2) conjugate combined with a sandwich format, the present method provides a dynamic range for CEA determination of 2×10-16 to 2×10-8 M and a detection limit of 0.07 fM. This biosensing approach demonstrates good reproducibility and high specificity for CEA in real serum samples providing a promising method to evaluate CEA in human serum for early diagnosis and monitoring of cancer.
TL;DR: The present review provides a state-of-the-art conspectus on the industrial and biomedical applications of antimicrobial gum-based biocomposites.
Abstract: Gum polysaccharides are derived from renewable sources. They are readily available, inexpensive, non-hazardous and eco-friendly. Depending upon the source, gums may be categorized as microbial gums, plant exudate gums or seed gums. Naturally occurring gum carbohydrates find multiple applications in the biomedical arena, compared with synthetic compounds, because of their unique structures and functionalities. Gums and their biocomposites are preferred for sustained drug delivery because they are safe and edible as well as more susceptible to biodegradation. The present review provides a state-of-the-art conspectus on the industrial and biomedical applications of antimicrobial gum-based biocomposites. Different kinds of gums polysaccharides will first be addressed based on their sources. Metal-, carbon- and organic-based nanostructures that are used in gum nanocomposites will then be reviewed with respect to their industrial and biomedical applications, to provide a backdrop for future research.
TL;DR: In this article, the potential applications of electrochemical conducting polymer (CP)-based electrochemical biosensors in COVID-19 detection based on their applications for the detection of various biomarkers such as DNA/RNA, proteins, whole viruses, and antigens.
Abstract: Rapid, accurate, portable, and large-scale diagnostic technologies for the detection of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) are crucial for controlling the coronavirus disease (COVID-19). The current standard technologies, i.e., reverse-transcription polymerase chain reaction, serological assays, and computed tomography (CT) exhibit practical limitations and challenges in case of massive and rapid testing. Biosensors, particularly electrochemical conducting polymer (CP)-based biosensors, are considered as potential alternatives owing to their large advantages such as high selectivity and sensitivity, rapid detection, low cost, simplicity, flexibility, long self-life, and ease of use. Therefore, CP-based biosensors can serve as multisensors, mobile biosensors, and wearable biosensors, facilitating the development of point-of-care (POC) systems and home-use biosensors for COVID-19 detection. However, the application of these biosensors for COVID-19 entails several challenges related to their degradation, low crystallinity, charge transport properties, and weak interaction with biomarkers. To overcome these problems, this study provides scientific evidence for the potential applications of CP-based electrochemical biosensors in COVID-19 detection based on their applications for the detection of various biomarkers such as DNA/RNA, proteins, whole viruses, and antigens. We then propose promising strategies for the development of CP-based electrochemical biosensors for COVID-19 detection.
TL;DR: The application of microfluidic paper-based assays to the detection of many common human diseases using 3 non-invasive samples sources such as saliva, tears and sweat is described.
Abstract: Microfluidic paper-based analysis devices (μPADs) have undergone tremendous development in recent years and now provide a feasible low-cost alternative to traditional laboratory tests for the diagnosis of many common diseases and disorders. As such, they are of great interest and importance in developing regions of the world with a lack of medical resources and associated infrastructures. This review examines the advances made in microfluidic paper-based diagnostic technology in the past five years and describes the application of microfluidic paper-based assays to the detection of many common human diseases using 3 non-invasive samples sources such as saliva, tears and sweat. The review commences by introducing the basic principles of fluid transport in microfluidic paper-based devices. The structures and actuation systems used in common paper-based devices are then introduced and explained. A systematic review of recent proposals for the application of paper-based devices to the diagnosis of common human diseases is then presented. The review concludes with a brief discussion of the challenges facing the microfluidics paper-based diagnosis field in the coming years and the emerging opportunities for future research.