Assessing respiratory complications by carbon dioxide sensing platforms: Advancements in infrared radiation technology and IoT integration

Respiratory illness demands pragmatic clinical monitoring and diagnosis to curb numerous fatal diseases in all aged groups. Due to the complicated instrumentation, long amplification periods, and restricted number of simultaneous detections, present clinically available multiplex diagnostic technologies are difficult to deploy the onsite diagnostic platforms. The futuristic assessment of medical diagnosis eases the respiratory monitoring using exhaled breath, due to the simple and comfort non-invasive detecting techniques. Carbon dioxide (CO2) stands as a promising biomarker and has been identified in exhaled breath samples that distinguish different respiratory issues. State-of-the-art CO2 gas sensing strategies are recognized with the growth of modern telecommunication technologies for real-time respiratory illness monitoring and diagnosis using exhaled breath. The presented article reviews the existing CO2 gas sensors and their developments towards medical applications. With that, the advancement of infrared (IR) CO2 gas sensors with distinguished light and sensing properties in detecting respiratory disorders are overviewed. The development of optimal CO2 gas sensing strategy incorporated with Internet of Things (IoT) technology is over-reviewed. The hurdles encountered in the existing research and future preference with real-time CO2 monitoring and diagnosing respiratory disorders with the advancement attained in IR sensing technology and IoT networking are highlighted

Non-protein coding RNA sequences mediate specific colorimetric detection of Staphylococcus aureus on unmodified gold nanoparticles

Abstract Nonprotein coding RNA (npcRNA) is a transcribed gene sequence that is not able to translate into protein, yet it executes a specific function in modulation and regulation mechanisms. As npcRNA is highly resistant to the mutation, the Sau-02 npcRNA gene and its probe oligonucleotide, which are specifically present in Staphylococcus aureus and in methicillin-resistant S. aureus only, used to develop a highly specific and sensitive colorimetric assay on unmodified gold nanoparticles (AuNPs). Hybridization between the npcRNA Sau-02 gene sequences was detected through noncrosslinking AuNP aggregation in salt solution in the presence of probe-target gene sequences. AuNPs of 10 and 15 nm in sizes with monovalent ion salt (NaCl) solution were optimized as the ideal tool for investigating the stability of AuNPs upon the addition of gene sequences. The state dispersed and aggregated forms of 10 nm AuNPs with the presented colorimetric assay were justified through field emission scanning electron microscopy and atomic force microscopy. The particle distribution of two different AuNP states was evaluated through particle distribution analysis. The lowest detection amount of S. aureus npcRNA from the colorimetric assay performed was 6 pg/µL, as the color of AuNPs turned blue with the presence of probe oligonucleotides and target gene sequences

Engineered nanostructures to carry the biological ligands

Different nanostructures were engineered with the nanoscale dimension lesser than 100 nm. These nanostructures include silver, cellulose nanoparticles and single-walled carbon nanotube (SWCNT). Biological ligands were obtained from the medicinally important herbal plants, such as Solanum trilobatum and Hempedu bumi and conjugated with the nanostructures silver nanoparticle and SWCNT, respectively. On the other hand, bio-ligands from cow urine were encapsulated in the cellulose nanoparticle. To confirm morphology these nanostructures, they were observed under Field Emission Scanning Electron Microscope and the results displayed the uniformed nanostructures. Further, biological ligand carrying ability of these nanostructures was confirmed by the bacterial inhibition assay on the agar plate. This study provided the evidence on the capability of nanostructures to carry the biological ligands

Engineered nanostructures to carry the biological ligands

Different nanostructures were engineered with the nanoscale dimension lesser than 100 nm. These nanostructures include silver, cellulose nanoparticles and single-walled carbon nanotube (SWCNT). Biological ligands were obtained from the medicinally important herbal plants, such as Solanum trilobatum and Hempedu bumi and conjugated with the nanostructures silver nanoparticle and SWCNT, respectively. On the other hand, bio-ligands from cow urine were encapsulated in the cellulose nanoparticle. To confirm morphology these nanostructures, they were observed under Field Emission Scanning Electron Microscope and the results displayed the uniformed nanostructures. Further, biological ligand carrying ability of these nanostructures was confirmed by the bacterial inhibition assay on the agar plate. This study provided the evidence on the capability of nanostructures to carry the biological ligands

Aptasensing nucleocapsid protein on nanodiamond assembled gold interdigitated electrodes for impedimetric SARS-CoV-2 infectious disease assessment

In an aim of developing portable biosensor for SARS-CoV-2 pandemic, which facilitates the point-of-care aptasensing, a strategy using 10 µm gap-sized gold interdigitated electrode (AuIDE) is presented. The silane-modified AuIDE surface was deposited with ~20 nm diamond and enhanced the detection of SARS-CoV-2 nucleocapsid protein (NCP). The characteristics of chemically modified diamond were evidenced by structural analyses, revealing the cubic crystalline nature at (220) and (111) planes as observed by XRD. XPS analysis denotes a strong interaction of carbon element, composed ~95% as seen in EDS analysis. The C–C, C[dbnd]C, C[dbnd]O, C[dbnd]N functional groups were well-refuted from XPS spectra of carbon and oxygen elements in diamond. The interrelation between elements through FTIR analysis indicates major intrinsic bondings at 2687-2031 cm-1. The aptasensing was evaluated through electrochemical impedance spectroscopy measurements, using NCP spiked human serum. With a good selectivity the lower detection limit was evidenced as 0.389 fM, at a linear detection range from 1 fM to 100 pM. The stability, and reusability of the aptasensor were demonstrated, showing ~30% and ~33% loss of active state, respectively, after ~11 days. The detection of NCP was evaluated by comparing anti-NCP aptamer and antibody as the bioprobes. The determination coefficients of R2 = 0.9759 and R2 = 0.9772 were obtained for aptamer- and antibody-based sensing, respectively. Moreover, the genuine interaction of NCP aptamer and protein was validated by enzyme linked apta-sorbent assay. The aptasensing strategy proposed with AuIDE/diamond enhanced sensing platform is highly recommended for early diagnosis of SARS-CoV-2 infection

Engineered nanostructures to carry the biological ligands

Different nanostructures were engineered with the nanoscale dimension lesser than 100 nm. These nanostructures include silver, cellulose nanoparticles and single-walled carbon nanotube (SWCNT). Biological ligands were obtained from the medicinally important herbal plants, such as Solanum trilobatum and Hempedu bumi and conjugated with the nanostructures silver nanoparticle and SWCNT, respectively. On the other hand, bio-ligands from cow urine were encapsulated in the cellulose nanoparticle. To confirm morphology these nanostructures, they were observed under Field Emission Scanning Electron Microscope and the results displayed the uniformed nanostructures. Further, biological ligand carrying ability of these nanostructures was confirmed by the bacterial inhibition assay on the agar plate. This study provided the evidence on the capability of nanostructures to carry the biological ligands

Transistor-based Biomolecule Sensors: Recent Technological Advancements and Future Prospects

10.1080/10408347.2021.2002133Critical Reviews in Analytical Chemistry5351044-106

Failure analysis on silicon semiconductor device materials: optical and high-resolution microscopic assessments

Defects of silicon (Si) semiconductor epilayers are crucial to be identified at laboratory environs. The identification of failure and its rectification at laboratory settings is essential for large-scaling manufacturing of narrowed down semiconductor devices. This research documented the inspection, identification and the solution for defects found in the Si semiconductor epilayers, fabricated by a simple and conventional photolithography technique, with the integration of metal oxide nanomaterial, zinc oxide (ZnO). The semiconductor epilayers, Si wafer, Si oxide and ZnO coated SiO2 layer were formed and examined. Optical microscope images [high power microscope (HPM) and 3D profilometer] reveal smooth surface of semiconductor epilayers development through thermal oxidation and photolithography techniques. High power ultraviolet-visible (UV-Vis) justified the accuracy of wet thermal oxidation by examining the thickness of oxide layer on Si wafer at 3837.3 Å. The X-ray diffraction (XRD) analysis of sol-gel synthesized ZnO affirmed the hexagonal crystalline state and its nanoscale size at 54 nm. Field emission scanning electron microscopy (FESEM) has shown the insight of Si epilayer morphology with its elemental composition, which provides details of foreign substances on semiconductor surface. ZnO deposited Si epilayer was prepared through lamella preparation, prior to the cross-sectional field emission transmission electron microscopy (FETEM) analysis of the semiconductor, which revealed the uniformity of fabrication and ZnO distribution at Si epilayer. Failure analysis reported several defects on the Si epilayers in the state of patches and accumulation of impurities. The potential cause of the defects and the respective solutions are discussed as the accuracy and handling must be ensured throughout the fabrication process, to develop a flawless semiconductor for high performance applications