Nanotechnology-assisted liquid crystals-based biosensors: Towards fundamental to advanced applications

Mesophase Behavior of Molecules Containing Three Benzene Rings Connected via Imines and Ester Linkages

Ten new compounds based on the methineazo-azomethine (CH=N-N=CH) and ester linking groups were prepared and investigated for their mesophase behavior and optical stability, and liquid crystals of 4-substituted phenyl methineazo-azomethine phenyl 4-alkoxybenzoates, I n a-e , were investigated. An alkoxy group with a length between 8 and 12 carbons is attached to the phenyl eater wing, while the other terminal ring is substituted in its 4-position with one of the polar NO2, F, Cl, CH3O, and N(CH3)2 groups. The molecular structures of the newly prepared compounds were verified by using 1H NMR, 13C NMR, and elemental analysis. Differential scanning calorimetry and polarized optical microscopy were applied to investigate their mesophase behavior. All members of the prepared homologous series showed excellent thermal mesomorphic stability over wide temperature ranges. The geometrical and thermal properties of the investigated compounds were verified via density functional theory (DFT). The theoretical results revealed that all of the compounds are almost planar. Finally, the experimentally established values of the mesophase data were correlated with the predicted quantum chemical characteristics evaluated by DFT.

Visual Biosensing with Specific Liquid-Based Interface Behaviors

Liquid-based interface behaviors at micro/nano or even smaller scales induced by biomolecules take us into a fascinating realm, fostering a deeper understanding and innovation in visual biosensing. This biosensing technology, grounded in specific liquid-based interface behaviors, redefines how diseases can be detected, monitored, and diagnosed in resource-limited settings, providing rapid, cost-effective, and self-testing solutions to the current healthcare landscape. To date, the technology has witnessed significant advancements in visual sensing, driven by diverse liquid-based materials, advanced nanomanufacturing techniques, and a profound understanding of interface-material interactions. In this Perspective, we discuss and elucidate the interface biosensing mechanisms arising from three types, including liquid-solid, liquid-liquid, and liquid-gas interfaces, and we provide insights into the challenges and future development of visual biosensing applications.

Nano/Micro-Structural Supramolecular Biopolymers: Innovative Networks with the Boundless Potential in Sustainable Agriculture

Sustainable agriculture plays a crucial role in meeting the growing global demand for food while minimizing adverse environmental impacts from the overuse of synthetic pesticides and conventional fertilizers. In this context, renewable biopolymers being more sustainable offer a viable solution to improve agricultural sustainability and production. Nano/micro-structural supramolecular biopolymers are among these innovative biopolymers that are much sought after for their unique features. These biomaterials have complex hierarchical structures, great stability, adjustable mechanical strength, stimuli-responsiveness, and self-healing attributes. Functional molecules may be added to their flexible structure, for enabling novel agricultural uses. This overview scrutinizes how nano/micro-structural supramolecular biopolymers may radically alter farming practices and solve lingering problems in agricultural sector namely improve agricultural production, soil health, and resource efficiency. Controlled bioactive ingredient released from biopolymers allows the tailored administration of agrochemicals, bioactive agents, and biostimulators as they enhance nutrient absorption, moisture retention, and root growth. Nano/micro-structural supramolecular biopolymers may protect crops by appending antimicrobials and biosensing entities while their eco-friendliness supports sustainable agriculture. Despite their potential, further studies are warranted to understand and optimize their usage in agricultural domain. This effort seeks to bridge the knowledge gap by investigating their applications, challenges, and future prospects in the agricultural sector. Through experimental investigations and theoretical modeling, this overview aims to provide valuable insights into the practical implementation and optimization of supramolecular biopolymers in sustainable agriculture, ultimately contributing to the development of innovative and eco-friendly solutions to enhance agricultural productivity while minimizing environmental impact.

Microviscosity-Assisted Disaggregation of a Model Ophthalmic Drug and FRET-Controlled Singlet Oxygen Generation in Lyotropic Liquid Crystals

Different phases of lyotropic liquid crystals (LLCs), made up of mesogen-like sodium dodecyl sulfate (SDS), mainly bestow different bulk viscosities. Along with this, the role of microviscosities of the individual LLC phases is of immense interest because a minute change in it due to guest incorporation can cause significant alteration in their property as a potential energy transfer scaffold. Recently, LLCs have been identified as plausible drug delivery agents for ocular treatments. In this direction, the present work illustrates photophysical modulations of an important laser dye as well as an ophthalmic medicine, coumarin 6 (C6), inside different LLC phases in an aqueous medium. C6 molecules spontaneously accumulate in water, leading to aggregation-caused quenching (ACQ) of fluorescence. However, the different phases of the LLCs prepared from SDS and water helped in disintegrating the C6 colonies to various extents depending upon the microviscosity. The heterogeneity in the LLC phases, in turn, could modulate the Förster resonance energy transfer (FRET) between C6 and the LLC incorporated with N-doped carbon nanoparticles (N-CNPs). The N-CNPs act as potential photosensitizers and generate singlet oxygen (1O2), a reactive oxygen species (ROS), to different extents. Microviscosities of the prepared LLCs were calculated by using fluorescence correlation spectroscopy (FCS). The different phases of the LLCs, viz., lamellar and hexagonal, with different microviscosities controlled the extent of C6 disaggregation and hence the FRET and the ROS generation. The results are encouraging since ROS generation has a significant role in the vision mechanism and PDT-based applications. LLC-based drug administration with potential FRET to control ROS generation may become handy in ophthalmology. The LLC phases used in this experiment not only served the purpose of drug delivery but also the photophysical events therein are compatible with the ocular environment.

Liquid foams as sensors for the detection of biomarkers

Bioassays are widely used in healthcare to detect and quantify biomarkers, such as molecules or enzymes, which are crucial in monitoring diseases and health conditions. In developed countries, healthcare professionals use specialized reagents and equipment's to perform these bioassays. However, in less-industrialized countries, the creation of low cost, fast, and technically simple bioassays is required. Herein, we propose a simple approach for detecting biochemical markers using host-guest complexes containing a surfactant. When the biochemical marker is present, the host-guest complex is disrupted, releasing the surfactant and producing foam. The read-out mechanism relies on the change of foam volume as function of biomarker concentration. This change is quantifiable by the naked eye and can be measured with a simple ruler. We claim that the use of foams as sensing tool is an attractive, inexpensive, fast, and easy to handle on-site detection method.

A simple and robust aptasensor assembled on surfactant-mediated liquid crystal interface for ultrasensitive detection of mycotoxin

Here, a simple aptasensing approach is represented to sensitively detect ochratoxin A (OTA) as one of the most perilous mycotoxins with carcinogenic, nephrotoxic, teratogenic, and immunosuppressive sequels on human health. The aptasensor is based on the alteration in the orientational order of liquid crystal (LC) molecules at the surfactant-arranged interface. Homeotropic alignment of LCs is achieved by the interaction of the surfactant tail with LCs. By perturbing the alignment of LCs due to the electrostatic interaction of the aptamer strand with the surfactant head, a colorful polarized view of the aptasensor substrate is induced drastically. While OTA causes the re-orientation of LCs to a vertical state by forming an OTA-aptamer complex that induces darkness of the substrate. This study shows that the length of the aptamer strand impacts the efficiency of the aptasensor; longer strand results in the greater disruption of LCs, and therefore, increases the aptasensor sensitivity. Hence, the aptasensor can determine OTA in the linear concentration range of 0.1 fM-1 pM as low as 0.021 fM. The aptasensor is capable to monitor OTA in grape juice, coffee drink, corn, and human serum real samples. The proposed LC-based aptasensor provides a cost-effective, easy-to-carry, operator-independent, and user-friendly array with great potential to develop portable sensing gadgets for food quality control and health care monitoring.

Liquid crystal-assisted optical biosensor for early-stage diagnosis of mammary glands using HER-2

Breast cancer (BC) is one of the most commonly diagnosed cancers and the second leading cause of cancer mortality among women around the world. The purpose of this study is to present a non-labeled liquid crystal (LC) biosensor, based on the inherent feature of nematic LCs, for the evaluation of BC using the human epidermal growth factor receptor-2 (HER-2) biomarker. The mechanism of this sensing is supported by surface modification with dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) encouraging the long alkyl chains that induce a homeotropic orientation of the LC molecules at the interface. To enhance the binding efficacy of more HER-2 antibody (Ab) on LC aligning agents, a simple ultraviolet radiation-assisted method was also used to increase functional groups on the DMOAP coated slides, thereby improving binding affinity and efficiency onto HER-2 Abs. The designed biosensor makes use of the specific binding of HER-2 protein to HER-2 Ab and disruption of the orientation of LCs. This orientation change leads to a transition of the optical appearance from dark to birefringent, enabling the detection of HER-2. This novel biosensor exhibits a linear optical response to HER-2 concentration in the wide dynamic range of 10^-6-10² ng/mL, with an ultra-low detection limit of 1 fg/mL. As a proof of concept, the designed LC biosensor was successfully investigated for the quantification of HER-2 protein in patients suffering from BC. Owing to the sensitivity, selectivity, and label-free detection, this biosensor may amplify the application of LC-based biosensors for the detection of most types of cancers.

Nanotechnology-Enabled Biosensors: A Review of Fundamentals, Design Principles, Materials, and Applications

Biosensors are modern engineering tools that can be widely used for various technological applications. In the recent past, biosensors have been widely used in a broad application spectrum including industrial process control, the military, environmental monitoring, health care, microbiology, and food quality control. Biosensors are also used specifically for monitoring environmental pollution, detecting toxic elements' presence, the presence of bio-hazardous viruses or bacteria in organic matter, and biomolecule detection in clinical diagnostics. Moreover, deep medical applications such as well-being monitoring, chronic disease treatment, and in vitro medical examination studies such as the screening of infectious diseases for early detection. The scope for expanding the use of biosensors is very high owing to their inherent advantages such as ease of use, scalability, and simple manufacturing process. Biosensor technology is more prevalent as a large-scale, low cost, and enhanced technology in the modern medical field. Integration of nanotechnology with biosensors has shown the development path for the novel sensing mechanisms and biosensors as they enhance the performance and sensing ability of the currently used biosensors. Nanoscale dimensional integration promotes the formulation of biosensors with simple and rapid detection of molecules along with the detection of single biomolecules where they can also be evaluated and analyzed critically. Nanomaterials are used for the manufacturing of nano-biosensors and the nanomaterials commonly used include nanoparticles, nanowires, carbon nanotubes (CNTs), nanorods, and quantum dots (QDs). Nanomaterials possess various advantages such as color tunability, high detection sensitivity, a large surface area, high carrier capacity, high stability, and high thermal and electrical conductivity. The current review focuses on nanotechnology-enabled biosensors, their fundamentals, and architectural design. The review also expands the view on the materials used for fabricating biosensors and the probable applications of nanotechnology-enabled biosensors.

Calixarene Functionalized Supramolecular Liquid Crystals and Their Diverse Applications

Liquid crystals are considered to be the fourth state of matter with an intermediate order and fluidity in comparison to solids and liquids. Calixarenes are among one of the most versatile families of building blocks for supramolecular chemistry due to their unique vaselike structure that can be chemically engineered to have different shapes and sizes. During the last few decades, calixarenes have drawn much attention in the field of supramolecular chemistry due to their diverse applications in the fields of ion and molecular recognition, ion-selective electrodes for catalysis, drug delivery, gelation, organic electronics and sensors, etc. Imbuing liquid crystallinity to the calixarene framework leads to functionalized calixarene derivatives with fluidity and order. Columnar self-assembly of such derivatives in particular enhance the charge migration along the column due to the 1D stacking due to the enhanced π-π overlap. Considering limited reports and reviews on this new class of calixarene based liquid crystals, a comprehensive account of the synthesis of calixarene liquid crystals along with their mesomorphic behavior and potential applications are presented in this review.

Rapid, label-free and low-cost diagnostic kit for COVID-19 based on liquid crystals and machine learning

We report a label-free method for detection of the SARS-CoV-2 virus in nasopharyngeal swab samples without purification steps and multiplication of the target which simplifies and expedites the analysis process. The kit consists of a textile grid on which liquid crystals (LC) are deposited and the grid is placed in a crossed polarized microscopy. The swab samples are subsequently placed on the LCs. In the presence of a particular biomolecule, the direction of LCs changes locally based on the properties of the biomolecule and forms a particular pattern. As the swab samples are not perfectly purified, image processing and machine learning techniques are employed to detect the presence of specific molecules or quantify their concentrations in the medium. The method can differentiate negative and positive COVID-19 samples with an accuracy of 96% and also differentiate COVID-19 from influenza types A and B with an accuracy of 93%. The kit is portable, simple to manufacture, convenient to operate, cost effective, rapid and sensitive. The simplicity of the specimen processing, the speed of image acquisition, and fast diagnostic operations enable the deployment of the proposed technique for performing extensive on-spot screening of COVID-19 in public places.

Optical and Electrochemical Aptasensors Developed for the Detection of Alpha-Fetoprotein

Early diagnosis of hepatocellular carcinoma (HCC), a leading cause of cancer mortality, is decisive for successful treatment of this type of cancer and increasing the patients' survival rate. Alpha-fetoprotein (AFP) is a glycoprotein that has been currently employed as a potential serological biomarker for determination of HCC and several other cancers. Achieving highly sensitive and specific detection of this biomarker is an effective strategy to inhibit developing issues caused by the cancer. Though, traditional procedures cannot meet the requirements due to the technical drawbacks. Recently, growing number of aptamer-based biosensors (aptasensors) attracted important attention as superior diagnostic tools because of their unique properties such as high stability, target versatility and remarkable affinity and selectivity. Nanomaterials, which broadly employed in the structure of these aptasensors, can considerably enhance the detection limit and sensitivity of analytes determination. Therefore, this review selectively investigated the recent progresses in several different optical and electrochemical aptasensors and nano-aptasensors designed for AFP assay.

Borophene as an emerging 2D flatland for biomedical applications: current challenges and future prospects

Recently, two-dimensional (2D)-borophene has emerged as a remarkable translational nanomaterial substituting its predecessors in the field of biomedical sensors, diagnostic tools, high-performance healthcare devices, super-capacitors, and energy storage devices. Borophene justifies its demand due to high-performance and controlled optical, electrical, mechanical, thermal, and magnetic properties as compared with other 2D-nanomaterials. However, continuous efforts are being made to translate theoretical and experimental knowledge into pragmatic platforms. To cover the associated knowledge gap, this review explores the computational and experimental chemistry needed to optimize borophene with desired properties. High electrical conductivity due to destabilization of the highest occupied molecular orbital (HOMO), nano-engineering at the monolayer level, chemistry-oriented biocompatibility, and photo-induced features project borophene for biosensing, bioimaging, cancer treatment, and theragnostic applications. Besides, the polymorphs of borophene have been useful to develop specific bonding for DNA sequencing and high-performance medical equipment. In this review, an overall critical and careful discussion of systematic advancements in borophene-based futuristic biomedical applications including artificial intelligence (AI), Internet-of-Things (IoT), and Internet-of-Medical Things (IoMT) assisted smart devices in healthcare to develop high-performance biomedical systems along with challenges and prospects is extensively addressed. Consequently, this review will serve as a key supportive platform as it explores borophene for next-generation biomedical applications. Finally, we have proposed the potential use of borophene in healthcare management strategies.

Liquid Crystals: Versatile Self-Organized Smart Soft Materials

Smart soft materials are envisioned to be the building blocks of the next generation of advanced devices and digitally augmented technologies. In this context, liquid crystals (LCs) owing to their responsive and adaptive attributes could serve as promising smart soft materials. LCs played a critical role in revolutionizing the information display industry in the 20th century. However, in the turn of the 21st century, numerous beyond-display applications of LCs have been demonstrated, which elegantly exploit their controllable stimuli-responsive and adaptive characteristics. For these applications, new LC materials have been rationally designed and developed. In this Review, we present the recent developments in light driven chiral LCs, i.e., cholesteric and blue phases, LC based smart windows that control the entrance of heat and light from outdoor to the interior of buildings and built environments depending on the weather conditions, LC elastomers for bioinspired, biological, and actuator applications, LC based biosensors for detection of proteins, nucleic acids, and viruses, LC based porous membranes for the separation of ions, molecules, and microbes, living LCs, and LCs under macro- and nanoscopic confinement. The Review concludes with a summary and perspectives on the challenges and opportunities for LCs as smart soft materials. This Review is anticipated to stimulate eclectic ideas toward the implementation of the nature's delicate phase of matter in future generations of smart and augmented devices and beyond.

Applications of Microfluidics in Liquid Crystal-Based Biosensors

Liquid crystals (LCs) with stimuli-responsive configuration transition and optical anisotropic properties have attracted enormous interest in the development of simple and label-free biosensors. The combination of microfluidics and the LCs offers great advantages over traditional LC-based biosensors including small sample consumption, fast analysis and low cost. Moreover, microfluidic techniques provide a promising tool to fabricate uniform and reproducible LC-based sensing platforms. In this review, we emphasize the recent development of microfluidics in the fabrication and integration of LC-based biosensors, including LC planar sensing platforms and LC droplets. Fabrication and integration of LC-based planar platforms with microfluidics for biosensing applications are first introduced. The generation and entrapment of monodisperse LC droplets with different microfluidic structures, as well as their applications in the detection of chemical and biological species, are then summarized. Finally, the challenges and future perspectives of the development of LC-based microfluidic biosensors are proposed. This review will promote the understanding of microfluidic techniques in LC-based biosensors and facilitate the development of LC-based microfluidic biosensing devices with high performance.

A Single-Substrate Biosensor with Spin-Coated Liquid Crystal Film for Simple, Sensitive and Label-Free Protein Detection

A liquid crystal (LC)-based single-substrate biosensor was developed by spin-coating an LC thin film on a dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP)-decorated glass slide. Compared with the conventional sandwiched cell configuration, the simplified procedure for the preparation of an LC film allows the film thickness to be precisely controlled by adjusting the spin rate, thus eliminating personal errors involved in LC cell assembly. The limit of detection (LOD) for bovine serum albumin (BSA) was lowered from 10-5 g/mL with a 4.2-μm-thick sandwiched cell of the commercial LC E7 to 10-7 g/mL with a 4.2-μm-thick spin-coated E7 film and further to 10-8 g/mL by reducing the E7 film thickness to 3.4 μm. Moreover, by exploiting the LC film of the highly birefringent nematic LC HDN in the immunodetection of the cancer biomarker CA125, an LOD comparable to that determined with a sandwiched HDN cell was achieved at 10-8 g/mL CA125 using a capture antibody concentration an order of magnitude lower than that in the LC cell. Our results suggest that employing spin-coated LC film instead of conventional sandwiched LC cell provides a more reliable, reproducible, and cost-effective single-substrate platform, allowing simple fabrication of an LC-based biosensor for sensitive and label-free protein detection and immunoassay.

Bio-inspired graphene-based nano-systems for biomedical applications

The increasing demands of environmentally sustainable, affordable, and scalable materials have inspired researchers to explore greener nanosystems of unique properties which can enhance the performance of existing systems. Such nanosystems, extracted from nature, are state-of-art high-performance nanostructures due to intrinsic hierarchical micro/nanoscale architecture and generous interfacial interactions in natural resources. Among several, bio-inspired nanosystems graphene nanosystems have emerged as an essential nano-platform wherein a highly electroactive, scalable, functional, flexible, and adaptable to a living being is a key factor. Preliminary investigation project bio-inspired graphene nanosystems as a multi-functional nano-platform suitable for electronic devices, energy storage, sensors, and medical sciences application. However, a broad understanding of bio-inspired graphene nanosystems and their projection towards applied application is not well-explored yet. Considering this as a motivation, this mini-review highlights the following; the emergence of bio-inspired graphene nanosystems, over time development to make them more efficient, state-of-art technology, and potential applications, mainly biomedical including biosensors, drug delivery, imaging, and biomedical systems. The outcomes of this review will certainly serve as a guideline to motivate scholars to design and develop novel bio-inspired graphene nanosystems to develop greener, affordable, and scalable next-generation biomedical systems.

Label-Free Detection and Spectrometrically Quantitative Analysis of the Cancer Biomarker CA125 Based on Lyotropic Chromonic Liquid Crystal

Compared with thermotropic liquid crystals (LCs), the biosensing potential of lyotropic chromonic liquid crystals (LCLCs), which are more biocompatible because of their hydrophilic nature, has scarcely been investigated. In this study, the nematic phase, a mesophase shared by both thermotropic LCs and LCLCs, of disodium cromoglycate (DSCG) was employed as the sensing mesogen in the LCLC-based biosensor. The biosensing platform was constructed so that the LCLC was homogeneously aligned by the planar anchoring strength of polyimide, but was disrupted in the presence of proteins such as bovine serum albumin (BSA) or the cancer biomarker CA125 captured by the anti-CA125 antibody, with the level of disturbance (and the optical signal thus produced) predominated by the amount of the analyte. The concentration- and wavelength-dependent optical response was analyzed by transmission spectrometry in the visible light spectrum with parallel or crossed polarizers. The concentration of CA125 can be quantified with spectrometrically derived parameters in a linear calibration curve. The limit of detection for both BSA and CA125 of the LCLC-based biosensor was superior or comparable to that of thermotropic LC-based biosensing techniques. Our results provide, to the best of our knowledge, the first evidence that LCLCs can be applied in spectrometrically quantitative biosensing.

Cellular Investigations on Mechanistic Biocompatibility of Green Synthesized Calcium Oxide Nanoparticles with Danio rerio

The utility of calcium oxide nanoparticles in the biomedical and physical fields has instigated their biocompatible synthesis and production. Moreover, it is important to investigate their biocompatibility at the molecular level for biomedical and ecotoxicological concern. This study explores the green synthesis of calcium oxide nanoparticles (CaONP) using Crescentia cujete leaf extract. The synthesized CaONP were found to have a size of 62 ± 06 nm and a hydrodynamic diameter of 246 ± 12 nm, as determined by FE-SEM and dynamic light scattering (DLS). CaONP was stable in fish medium with a zeta potential of −23 ± 11 mV. The biocompatibility of the CaONP was investigated with adult zebrafish bearing an LC50 of 86.32 µg/mL. Cellular and molecular investigation revealed the mechanism of biocompatibility as a consequence of elicited reactive oxygen species leading to apoptosis, due to accumulation and internalization of CaONP in exposed zebrafish. The study provided detailed information about the mechanistic biocompatibility and a defined horizon of green synthesis of CaONP for biomedical and ecological purposes.

A facile method for the fabrication of hierarchically structured Ni2CoS4 nanopetals on carbon nanofibers to enhance non-enzymatic glucose oxidation

Unique Ni₂CoS₄-carbon nanofiber (CNF) composite nanostructures were fabricated using a simple electrospinning-assisted hydrothermal route and used for the rapid and accurate electrochemical oxidation of glucose in real samples at the trace level. Electrochemical impedance spectroscopy and cyclic voltammetry of unmodified and modified electrodes revealed low charge-transfer resistance and the excellent electrocatalytic sensing of glucose when using the Ni₂CoS₄-CNF at a low potential due to the combined benefits of the highly conductive Ni₂Co₂S₄ anchored to the large surface area of the CNFs. Amperometric analysis of the fabricated sensor has shown an extremely low limit of detection (0.25 nM) and a large linear range (5-70 nM) for glucose at a working potential of 0.54 V (vs. Hg/HgO). The practicability of the Ni₂CoS₄-CNF for use in glucose determination was tested withl human saliva, blood plasma, and fruit juice samples. The Ni₂CoS₄-CNF/GCE showed acceptable recovery values for human saliva (99.1-100.8%), blood plasma (98.6-101.5%), and fruit juice (95.1-105.7%) samples. The proposed sensor also exhibited outstanding electroanalytical characteristics for glucose oxidation in these samples, including reusability, repeatability, and interference resistance, even in the presence of other biological substances and organic and inorganic metal ions.

Conventional and unconventional ionic phenomena in tunable soft materials made of liquid crystals and nanoparticles

A great variety of tunable multifunctional materials can be produced by combining nanoparticles and liquid crystals. Typically, the tunability of such soft nanocomposites is achieved via external electric fields resulting in the field-induced reorientation of liquid crystals. This reorientation can be altered by ions normally present in liquid crystals in small quantities. In addition, nanomaterials dispersed in liquid crystals can also affect the behavior of ions. Therefore, an understanding of ionic phenomena in liquid crystals doped with nanoparticles is essential for future advances in liquid crystal-aided nanoscience and nanotechnology. This paper provides an overview of the ionic effects observed in liquid crystals doped with nanomaterials. An introduction to liquid crystals is followed by a brief overview of nanomaterials in liquid crystals. After giving a basic description of ions in liquid crystals and experimental methods to measure them, a wide range of ionic phenomena in liquid crystals doped with different types of nanomaterials is discussed. After that, both existing and emerging applications of tunable soft materials made of liquid crystals and nanodopants are presented with an emphasis on the role of ionic effects in such systems. Finally, the discussion of unsolved problems and future research directions completes the review.

Internet of medical things (IoMT)-integrated biosensors for point-of-care testing of infectious diseases

On global scale, the current situation of pandemic is symptomatic of increased incidences of contagious diseases caused by pathogens. The faster spread of these diseases, in a moderately short timeframe, is threatening the overall population wellbeing and conceivably the economy. The inadequacy of conventional diagnostic tools in terms of time consuming and complex laboratory-based diagnosis process is a major challenge to medical care. In present era, the development of point-of-care testing (POCT) is in demand for fast detection of infectious diseases along with “on-site” results that are helpful in timely and early action for better treatment. In addition, POCT devices also play a crucial role in preventing the transmission of infectious diseases by offering real-time testing and lab quality microbial diagnosis within minutes. Timely diagnosis and further treatment optimization facilitate the containment of outbreaks of infectious diseases. Presently, efforts are being made to support such POCT by the technological development in the field of internet of medical things (IoMT). The IoMT offers wireless-based operation and connectivity of POCT devices with health expert and medical centre. In this review, the recently developed POC diagnostics integrated or future possibilities of integration with IoMT are discussed with focus on emerging and re-emerging infectious diseases like malaria, dengue fever, influenza A (H1N1), human papilloma virus (HPV), Ebola virus disease (EVD), Zika virus (ZIKV), and coronavirus (COVID-19). The IoMT-assisted POCT systems are capable enough to fill the gap between bioinformatics generation, big rapid analytics, and clinical validation. An optimized IoMT-assisted POCT will be useful in understanding the diseases progression, treatment decision, and evaluation of efficacy of prescribed therapy.