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Background: Dengue is known as the most severe arboviral infection in the world spread by Aedes aegypti. However, conventional and laboratory-based enzyme-linked immunosorbent assays (ELISA) are the current approaches in detecting dengue virus (DENV), requiring skilled and well-trained personnel to operate. Therefore, the ultrasensitive and label-free technique of the Silicon Nanowire (SiNW) biosensor was chosen for rapid detection of DENV. Methods: In this study, a SiNW field-effect transistor (FET) biosensor integrated with a back-gate of the low-doped p-type Silicon-on-insulator (SOI) wafer was fabricated through conventional photolithography and Inductively Coupled Plasma – Reactive Ion Etching (ICP-RIE) for Dengue Virus type-2 (DENV-2) DNA detection. The morphological characteristics of back-gated SiNW-FET were examined using a field-emission scanning electron microscope supported by the elemental analysis via energy-dispersive X-ray spectroscopy. Results and Discussion: A complementary (target) single-stranded deoxyribonucleic acid (ssDNA) was recognized when the target DNA was hybridized with the probe DNA attached to SiNW surfaces. Based on the slope of the linear regression curve, the back-gated SiNW-FET biosensor demonstrated the sensitivity of 3.3 nAM-1 with a detection limit of 10 fM. Furthermore, the drain and back-gate voltages were also found to influence the SiNW conductance changed. Conclusion: Thus, the results obtained suggest that the back-gated SiNW-FET shows good stability in both biosensing applications and medical diagnosis throughout the conventional photolithography method.

The importance of nanotechnology in medical applications especially with biomedical sensing devices is undoubted. Several medical diagnostics have been developed by taking the advantage of nanomaterials, especially with electrical biosensors. Biosensors have been predominantly used for the quantification of different clinical biomarkers toward detection, screening, and follow-up the treatment. At present, ovarian cancer is one of the severe complications that cannot be identified until it becomes most dangerous as the advanced stage. Based on the American Cancer Society, 20% of cases involved in the detection of ovarian cancer are diagnosed at an early stage and 80% diagnosed at the later stages. The patient just has a common digestive problem and stomach ache as early symptoms and people used to ignore these symptoms. Micro ribonucleic acid (miRNA) is classified as small non-coding RNAs, their expressions change due to the association of cancer development and progression. This article reviews and discusses on the currently available strategies for the early detection of ovarian cancers using miRNA as a biomarker associated with electrical biosensors. A unique miRNA-based biomarker detections are specially highlighted with biosensor platforms to diagnose ovarian cancer.

The reliability and specificity of the Pap smear rely on the eyewitness to perceive and an assortment of cell variations in clinically obtained cervical specimens. The improvement in early diagnosis to distinguish Human Papillomavirus (HPV) infection has been an issue. ELISA has been intended to analyze the immune response against HPV, and they can be utilized to distinguish the phase of the infection. The objective of this study to characterize the performance of In Vitro Nucleic Acid Hybridization with a correlation with Liquid-Based Cytology and HPV DNA Genotyping Test to assess its use as the potential for the identification of high-risk HPV in cervical clinical specimens. Hybridization utilizing an in vitro nucleic acid DNA-based ELISA method was performed with an improved chemiluminescent for the qualitative and semi-quantitative identification of high-risk HPV in cervical specimens. For analyzing the reliability to identify HPV DNA in cervical Pap smear, we studied the effectiveness of FDA-approved Hybrid Capture II (HCII) utilizing cervical swapping from 20 patient clinical specimens. Two scrapes-outs were positive for the occurrence of HPV. Only specimens displayed positive with HCII test were further confirmed by HPV Genotyping Test. Specimen 2 and 13 were positive for one of the 13 high-risk types in HCII test. Specimen 2 was confirmed by HPV genotyping test as a positive high-risk HPV type 58.

Prognosis of early cancer detection becomes one of the tremendous issues in the medical health system. Medical debates among specialist doctor and researcher in therapeutic approaches became a hot concern for cervix cancer deficiencies early screening, risk factors cross-reaction, portability device, rapid and free labeling system. The electrical biosensing based system showed credibility in higher specificity and selectivity due to hybridization of DNA duplex between analyte target and DNA probes. Electrical DNA sensor for cervix cancer has attracted too many attentions to researcher notification based on high performance, easy to handle, rapid system and possible to miniaturize. This review explores the current progression and future insignificant for HPV E6 genobiosensing for early Detection Strategies of Cervical Cancer.

A titanium dioxide nanoparticle (TiO2 NP)–mediated resistive biosensor is described for the determination of DNA fragments of Escherichia coli O157:H7 (E. coli O157:H7). The sol-gel method was used to synthesize the TiO2 NP, and microlithography was applied to fabricate the interdigitated sensor electrodes. Conventional E. coli DNA detections are facing difficulties in long-preparation-and-detection-time (more than 3 days). Hence, electronic biosensor was introduced by measuring the current-voltage (I–V) DNA probe without amplification of DNA fragments. The detection scheme is based on the interaction between the electron flow on the sensor and the introduction of negative charges from DNA probe and target DNA. The biosensor has a sensitivity of 1.67 × 1013 Ω/M and a wide analytical range. The limit detection is down to 1 × 10−11 M of DNA. The sensor possesses outstanding repeatability and reproducibility and is cabable to detect DNA within 15 min in a minute-volume sample (1 μL).

According to recent studies, millions of people are suffering from Arsenic (As) toxicity contamination. Arsenic is one of the most toxic and carcinogenic chemical elements and its contamination in paddy field has become a chronic problem. In the agricultural sector, arsenic-contaminated water irrigation has a higher level of arsenic contamination on the top soil, which can affect the quality of crop production such as rice plants. Rice plant requires a considerable amount of water to complete its lifecycle. In Asean countries like Malaysia, Indonesia and Thailand, Arsenic intake from rice is significantly higher, as rice plants have a special ability to take up arsenic from the soil and water used for irrigation. The transfer of arsenic from soil to plant systems is a serious issue that leads to considerable human exposure. Nanotechnology application plays vital role for any field work and research. In this research, the implementation of nanotechnology approach such as silica nanoparticles are able to remove the Arsenic heavy metal contamination. This paper focused on arsenic heavy metal removal using silica nanoparticles analaysed using spectrophotometric method.

The aim of the research study to design high sensitive biosensor for medical applications. IDE pattern was designed using AutoCAD software with 5 µm ginger gap. The fabrication process was done using a conventional photolithography process and standard CMOS process. The fabricated electrode was physically characterized using a low power microscope (LPM) and a high power microscope (HPM). The electrically validated through I-V measurements and chemically tested with different pH buffer solutions. Al IDE was well fabricated with 0.1 µm tolerance between the design mask and fabricated IDEs. Electrical measurements confirmed that IDE was well fabricated without any shortage and results of similar IDE samples were confirmed that the repeatability of the device. The extremely small current variations in nano ampere range were quantitatively detected using an extra small volume of 2 µl for different pH buffer solutions. It is confirmed that IDEs are sensitive in both alkali and hydroxyl ions medium.

The persistent infection by high risk HPV is a necessary but not sufficient cause of this cancer which develops over a long period through precursor lesions which can be detected by electrochemical impedance sensor. The HPV driven molecular mechanisms underlying the development of cervical lesions have provided a number of potential biomarkers for both diagnostic and prognostic use in the clinical management of women with HPV related cervical disease and these biomarkers can also be used to increase the positive predictive value of current methods. The most influential methods for the detection and identification of HPV using gold nanoparticle (GNP) included electrochemical impedance sensor will visit their sensitivity, selectivity and characteristic detection on synthetic target which are complement of the DNA, non-complement of the DNA and mismatch of the DNA. In difference concentration of synthetic target, which stage can get the exactly value to determine the HPV in strain 16 was evaluated in this research studies.

Amplification of nano and mircoampere electrical signal to the detectable range is essential in the biosensor field. This research is mainly focused on design an amplifier circuit to capture and amplify three different range of current as nano, micro and mili ampere and convert it to detectable voltage range as an output signal to the processing circuit. The Proteus 8 Pro software was used to design, simulate and calibrate the amplifier circuit. Firstly, current input as mili, micro and nano current were flown through 0.1 mΩ, 10 Ω and 10 KΩ resistors, respectively to convert different current inputs to the similar range in micro voltage. The MAX 4238 opamp IC was used to amplify micro voltage to mili voltage. LM 358 dual operational amplifier was used to supply virtual ground to MAX 4238 amplifier. The amplified output voltage of three different current inputs as nano, micro and mili were nearly equal to theoretical outputs.

A gene sensor for rapid detection of the Human Papillomavirus 16 (HPV 16) which is associated with the appearance of cervical cancer was developed. The assay is based on voltammetric determination of HPV 16 DNA by using interdigitated electrodes modified with titanium dioxide nanoparticles. Titanium dioxide nanoparticles (NPs) were used to modify a semiconductor-based interdigitated electrode (IDE). The surface of the NPs was then functionalized with a commercial 24-mer oligomer DNA probe for HPV 16 that was modified at the 5′ end with a carboxyl group. If the probe interacts with the HPV 16 ssDNA, the current, best measured at a working voltage of 1.0 V, increases. The gene sensor has has a ∼ 0.1 fM limit of detection which is comparable to other sensors. The dielectric voltammetry analysis was carried out from 0 V to 1 V. The electrochemical sensitivity of the IDE is 2.5 × 10−5 μA·μM−1·cm−2.

In this paper, a label-free approach utilizing field-effect transistor (FET) biosensor is presented and demonstrated for deoxyribonucleic acid (DNA) detection related to dengue virus. The biologically active element (in this case for DNA) will have a reaction with a physical transducer (i.e. channel area that connecting the source and drain) and transforms the reaction into a quantifiable signal. This event occurs when an analyte is bound to the recognition element after surface modification, the charge distribution at the surface resulting in current flow across the channel. The field-effect transistor was fabricated using the conventional photolithography approach on thin silicon-on-insulator (SOI) wafer. The source and drain are either doped or undoped (as it initial intrinsic impurity is 1x1015 cm−3). The fabricated device of FET was then observed under scanning electron microscope (SEM), atomic force microscope (AFM), and 3D nano-profilometer to characterize the surface morphology. In addition, the electrical characterization was also performed using Keithley 6487 picoammeter to examine and analyze the bare device. Lastly, the diagnosis of dengue fever is performed by functionalizing the bio-receptor at the channel of the FET which is served as a molecular gate by the binding of a target DNA and monitoring electrical response to the concentrations of dengue virus. The device was tested repeatedly by using different concentrations of DNA target dengue. This step was performed to detect the sensitivity of the device. The device shows a wide-range of detection capability for detection of DNA dengue. The demonstrated results show that the FET has excellent properties for detection of dengue virus with outstanding sensitivity and selectivity properties.