A novel carbon nanofibers grown on glass microballoons immunosensor: a tool for early diagnosis of malaria

Current Trends in Nanotechnology-Based Drug Delivery Systems for the Diagnosis and Treatment of Malaria: A Review

Malaria is still a major endemic disease transmitted in humans via Plasmodium-infected mosquitoes. The eradication of malarial parasites and the control measures have been rigorously and extensively deployed by local and international health organizations. Malaria's recurrence is a result of the failure to entirely eradicate it. The drawbacks related to malarial chemotherapy, non-specific targeting, multiple drug resistance, requirement of high doses, intolerable toxicity, indefinable complexity of Plasmodium's life cycle, and advent of drug-resistant strains of P. falciparum are the causes of the ineffective eradication measures. With the emergence of nanotechnology and its application in various industrial domains, the rising interest in the medical field, especially in epidemiology, has skyrocketed. The applications of nanosized carriers have sparked special attention, aiming towards minimizing the overall side effects caused due to drug therapy and avoiding bioavailability. The applications of concepts of nanobiotechnology to both vector control and patient therapy can also be one of the approaches. The current study focuses on the use of hybrid drugs as next-generation antimalarial drugs because they involve fewer drug adverse effects. The paper encompasses the numerous nanosized delivery-based systems that have been found to be effective among higher animal models, especially in treating malarial prophylaxis. This paper delivers a detailed review of diagnostic techniques, various nanotechnology approaches, the application of nanocarriers, and the underlying mechanisms for the management of malaria, thereby providing insights and the direction in which the current trends are imparted from the innovative and technological perspective.

Advancements in Nanofiber-Based Electrochemical Biosensors for Diagnostic Applications

Biosensors are analytical tools that can be used as simple, real-time, and effective devices in clinical diagnosis, food analysis, and environmental monitoring. Nanoscale functional materials possess unique properties such as a large surface-to-volume ratio, making them useful for biomedical diagnostic purposes. Nanoengineering has resulted in the increased use of nanoscale functional materials in biosensors. Various types of nanostructures i.e., 0D, 1D, 2D, and 3D, have been intensively employed to enhance biosensor selectivity, limit of detection, sensitivity, and speed of response time to display results. In particular, carbon nanotubes and nanofibers have been extensively employed in electrochemical biosensors, which have become an interdisciplinary frontier between material science and viral disease detection. This review provides an overview of the current research activities in nanofiber-based electrochemical biosensors for diagnostic purposes. The clinical applications of these nanobiosensors are also highlighted, along with a discussion of the future directions for these materials in diagnostics. The aim of this review is to stimulate a broader interest in developing nanofiber-based electrochemical biosensors and improving their applications in disease diagnosis. In this review, we summarize some of the most recent advances achieved in point of care (PoC) electrochemical biosensor applications, focusing on new materials and modifiers enabling biorecognition that have led to improved sensitivity, specificity, stability, and response time.

Antibody-free rapid diagnosis of malaria in whole blood with surface-enhanced Raman Spectroscopy using Nanostructured Gold Substrate

PURPOSE

The aim of this study is to establish a rapid antibody-free diagnostic method of malaria infection with Plasmodium falciparum and Plasmodium vivax in whole blood with Surface-enhanced Raman Spectroscopy using Nanostructured Gold Substrate.

MATERIALS AND METHODS

The blood samples collected from patients were first lysed and centrifuged before dropping on the gold nano-structure (AuNS) substrate. Malaria diagnosis was performed by detecting Raman peaks from Surface Enhanced Raman Spectroscopy (SERS) with a 532 nm laser excitation.

RESULTS

Raman peaks at 1370 cm-1, 1570 cm-1, and 1627 cm-1, known to have high specificity against interference from other mosquito-borne diseases such as Dengue and West Nile virus infection, were selected as the fingerprint markers associated with P. falciparum and P. vivax infection. The limit of detection was 10-5 dilution, corresponding to the concentration of parasitized blood cells of 100/mL. A total number of 25 clinical samples, including 5 from patients with P. falciparum infection, 10 with P. vivax infection and 10 from healthy volunteers, were evaluated to support its clinical practical use. The whole assay on malaria detection took 30 min to complete.

CONCLUSIONS

While the samples analyzed in this work have strong clinical relevance, we have clearly demonstrated that sensitive malaria detection using AuNS-SERS is a practical direction for rapid in-field diagnosis of malaria infection.

Recent Advances in the Development of Biosensors for Malaria Diagnosis

The impact of malaria on global health has continually prompted the need to develop more effective diagnostic strategies that could overcome deficiencies in accurate and early detection. In this review, we examine the various biosensor-based methods for malaria diagnostic biomarkers, namely; Plasmodium falciparum histidine-rich protein 2 (PfHRP-2), parasite lactate dehydrogenase (pLDH), aldolase, glutamate dehydrogenase (GDH), and the biocrystal hemozoin. The models that demonstrate a potential for field application have been discussed, looking at the fabrication and analytical performance characteristics, including (but not exclusively limited to): response time, sensitivity, detection limit, linear range, and storage stability, which are first summarized in a tabular form and then described in detail. The conclusion summarizes the state-of-the-art technologies applied in the field, the current challenges and the emerging prospects for malaria biosensors.

Ultrasensitive and label-free biosensor for the detection of Plasmodium falciparum histidine-rich protein II in saliva

Malaria elimination is a global public health priority. To fulfil the demands of elimination diagnostics, we have developed an interdigitated electrode sensor platform targeting the Plasmodium falciparum Histidine Rich Protein 2 (PfHRP2) protein in saliva samples. A protocol for frequency-specific PfHRP2 detection in phosphate buffered saline was developed, yielding a sensitivity of 2.5 pg/mL based on change in impedance magnitude of the sensor. This protocol was adapted and optimized for use in saliva with a sensitivity of 25 pg/mL based on change in resistance. Further validation demonstrated detection in saliva spiked with PfHRP2 from clinical isolates in 8 of 11 samples. With a turnaround time of ~2 hours, the label-free platform based on impedance sensors has the potential for miniaturization into a point-of-care diagnostic device for malaria elimination.

Current Trends of Nanobiosensors for Point-of-Care Diagnostics

In order to provide better-quality health care, it is very important that high standards of health care management are achieved by making timely decisions based on rapid diagnostics, smart data analysis, and informatics analysis. Point-of-care testing ensures fast detection of analytes near to the patients facilitating a better disease diagnosis, monitoring, and management. It also enables quick medical decisions since the diseases can be diagnosed at an early stage which leads to improved health outcomes for the patients enabling them to start early treatment. In the recent past, various potential point-of-care devices have been developed and they are paving the way to next-generation point-of-care testing. Biosensors are very critical components of point-of-care devices since they are directly responsible for the bioanalytical performance of an essay. As such, they have been explored for their prospective point-of-care applications necessary for personalized health care management since they usually estimate the levels of biological markers or any chemical reaction by producing signals mainly associated with the concentration of an analyte and hence can detect disease causing markers such as body fluids. Their high selectivity and sensitivity have allowed for early diagnosis and management of targeted diseases; hence, facilitating timely therapy decisions and combination with nanotechnology can improve assessment of the disease onset and its progression and help to plan for treatment of many diseases. In this review, we explore how nanotechnology has been utilized in the development of nanosensors and the current trends of these nanosensors for point-of-care diagnosis of various diseases.

Development of Electrochemical Nanosensor for the Detection of Malaria Parasite in Clinical Samples

In this study, electrochemical nanosensors were developed from the synthesized metal oxide (MO) nanoparticles by supporting it on a gold electrode (Au). The activity of the developed nanosensor toward the detection of malaria biomarker (β-hematin) was determined and the optimum conditions at which the maximum detection and quantification occurred were established. β-Hematin current response at the sensors was higher when compared with the bare Au electrode and followed the order Au-CuO (C) > Au-CuO (M) > Au-Fe₂O3 (M) > Au-Fe₂O3 (C) > Au-Al₂O3 (M) > Au-Al₂O3 (C) > bare Au. The developed sensors were stable with a relatively low current drop (10.61-17.35 %) in the analyte. Au-CuO sensor had the best performance toward the biomarker and quantitatively detected P. berghei in infected mice's serum samples at 3.60-4.8 mM and P. falciparum in human blood serum samples at 0.65-1.35 mM concentration.

Development of an Immunosensor for PfHRP 2 as a Biomarker for Malaria Detection

Plasmodium falciparum histidine-rich protein 2 (PfHRP 2) was selected in this work as the biomarker for the detection and diagnosis of malaria. An enzyme-linked immunosorbent assay (ELISA) was first developed to evaluate the immunoreagent’s suitability for the sensor’s development. A gold-based sensor with an integrated counter and an Ag/AgCl reference electrode was first selected and characterised and then used to develop the immunosensor for PfHRP 2, which enables a low cost, easy to use, and sensitive biosensor for malaria diagnosis. The sensor was applied to immobilise the anti-PfHRP 2 monoclonal antibody as the capture receptor. A sandwich ELISA assay format was constructed using horseradish peroxidase (HRP) as the enzyme label, and the electrochemical signal was generated using a 3, 3′, 5, 5′tetramethyl-benzidine dihydrochloride (TMB)/H₂O₂ system. The performance of the assay and the sensor were optimised and characterised, achieving a PfHRP 2 limit of detection (LOD) of 2.14 ng·mL⁻¹ in buffer samples and 2.95 ng∙mL⁻¹ in 100% spiked serum samples. The assay signal was then amplified using gold nanoparticles conjugated detection antibody-enzyme and a detection limit of 36 pg∙mL⁻¹ was achieved in buffer samples and 40 pg∙mL⁻¹ in serum samples. This sensor format is ideal for malaria detection and on-site analysis as a point-of-care device (POC) in resource-limited settings where the implementation of malaria diagnostics is essential in control and elimination efforts.

A multi-walled carbon nanotube–zinc oxide nanofiber based flexible chemiresistive biosensor for malaria biomarker detection

A flexible, lightweight and disposable chemiresistive biosensor for label free detection of the malaria biomarker.

A highly sensitive self assembled monolayer modified copper doped zinc oxide nanofiber interface for detection of Plasmodium falciparum histidine-rich protein-2: Targeted towards rapid, early diagnosis of malaria

Rapid, ultrasensitive diagnostic/triaging kits for early detection of malarial parasites are critical for prevention of malarial epidemic, especially in developing and tropical countries. Unlike traditional microscopic diagnosis, these kits rely on the detection of antigens specific to malarial parasites. One such antigen which is routinely used in these diagnostic kits is Histidine-rich protein-2; a protein synthesized and released into the blood stream by the parasite Plasmodium falciparum. In this paper, we demonstrate an ultrasensitive nanobiosensor detection platform for Histidine-rich protein-2 having a limit of detection of attogram/ml. This nanobiosensor platform comprises of Mercaptopropylphosphonic acid functionalized copper doped zinc oxide nanofibers synthesized by electrospinning technique. Ultrasensitivity of attogram/ml can be attributed to the complimentary effects of Mercaptopropylphosphonic acid and copper doping in zinc oxide. Mercaptopropylphosphonic acid enhances the functional groups required for immobilizing antibody. Copper doping in zinc oxide not only increases the conductivity of the nanofibers but also pre-concentrates the target analyte onto the Mercaptopropylphosphonic acid treated nanofiber surface due to inherent electric field generated at the copper/zinc oxide heterojunction interface. The impedimetric detection response of copper-doped zinc oxide nanofiber modified electrode shows excellent sensitivity (28.5 kΩ/(gm/ml)/cm(2)) in the detection ranges of 10 ag/ml-10 µg/ml, and a detection limit of 6 attogram/ml. In addition, the proposed biosensor is highly selective to targeted HRP2 protein with a relative standard deviation of 1.9% in the presence of various interference of nonspecific molecules. To the best of our knowledge, this biosensor shows the lowest detection limit of malarial parasites reported in the literature spanning different nanomaterials and different detection mechanisms. Since the nanobiosensor platform is based on immunoassay technique, with a little modification, it can be extended for developing point-of-care diagnostic devices for several biomarkers of importance.

State of the art of nanoforest structures and their applications

Forest-like nanostructures, their syntheses, properties, and applications are reviewed.