Emerging 0D, 1D, 2D, and 3D nanostructures for efficient point-of-care biosensing

Impact of mechanical cues on key cell functions and cell-nanoparticle interactions

In recent years, it has been recognized that mechanical forces play an important regulative role in living organisms and possess a direct impact on crucial cell functions, ranging from cell growth to maintenance of tissue homeostasis. Advancements in mechanobiology have revealed the profound impact of mechanical signals on diverse cellular responses that are cell type specific. Notably, numerous studies have elucidated the pivotal role of different mechanical cues as regulatory factors influencing various cellular processes, including cell spreading, locomotion, differentiation, and proliferation. Given these insights, it is unsurprising that the responses of cells regulated by physical forces are intricately linked to the modulation of nanoparticle uptake kinetics and processing. This complex interplay underscores the significance of understanding the mechanical microenvironment in shaping cellular behaviors and, consequently, influencing how cells interact with and process nanoparticles. Nevertheless, our knowledge on how localized physical forces affect the internalization and processing of nanoparticles by cells remains rather limited. A significant gap exists in the literature concerning a systematic analysis of how mechanical cues might bias the interactions between nanoparticles and cells. Hence, our aim in this review is to provide a comprehensive and critical analysis of the existing knowledge regarding the influence of mechanical cues on the complicated dynamics of cell-nanoparticle interactions. By addressing this gap, we would like to contribute to a detailed understanding of the role that mechanical forces play in shaping the complex interplay between cells and nanoparticles.

Synergizing Nanomaterials and Artificial Intelligence in Advanced Optical Biosensors for Precision Antimicrobial Resistance Diagnosis

Antimicrobial resistance (AMR) poses a critical global One Health concern, ensuing from unintentional and continuous exposure to antibiotics, as well as challenges in accurate contagion diagnostics. Addressing AMR requires a strategic approach that emphasizes early stage prevention through screening in clinical, environmental, farming, and livestock settings to identify nonvulnerable antimicrobial agents and the associated genes. Conventional AMR diagnostics, like antibiotic susceptibility testing, possess drawbacks, including high costs, time-consuming processes, and significant manpower requirements, underscoring the need for intelligent, prompt, and on-site diagnostic techniques. Nanoenabled artificial intelligence (AI)-supported smart optical biosensors present a potential solution by facilitating rapid point-of-care AMR detection with real-time, sensitive, and portable capabilities. This Review comprehensively explores various types of optical nanobiosensors, such as surface plasmon resonance sensors, whispering-gallery mode sensors, optical coherence tomography, interference reflection imaging sensors, surface-enhanced Raman spectroscopy, fluorescence spectroscopy, microring resonance sensors, and optical tweezer biosensors, for AMR diagnostics. By harnessing the unique advantages of these nanoenabled smart biosensors, a revolutionary paradigm shift in AMR diagnostics can be achieved, characterized by rapid results, high sensitivity, portability, and integration with Internet-of-Things (IoT) technologies. Moreover, nanoenabled optical biosensors enable personalized monitoring and on-site detection, significantly reducing turnaround time and eliminating the human resources needed for sample preservation and transportation. Their potential for holistic environmental surveillance further enhances monitoring capabilities in diverse settings, leading to improved modern-age healthcare practices and more effective management of antimicrobial treatments. Embracing these advanced diagnostic tools promises to bolster global healthcare capacity to combat AMR and safeguard One Health.

Block copolymer-derived recessed nanodisk-array electrodes for electrochemical detection of β-lactam antibiotics

Antimicrobial resistance (AMR) is one of the major socio-economic factors contributing to public health. β-lactams are most commonly prescribed drugs for variety of bacterial infections. Frequent use of antibiotics leads to AMR in humans and animals. The present work is focused on developing an electro-immunosensor to control and regulate the excessive use of antibiotics in animal-based food products. An amphiphilic block co-polymer poly(ethylene oxide-block-methyl methacrylate)(PEO-b-PMMA) was used to fabricate recessed nano-disk array electrode (RNE) and immobilized with Pen-Ab and Cef-Ab antibodies. The Limit of detection (LOD) of RNE working electrode was found to be 14.8 pM for penicillin and 13.8 pM for cefalexin with good selectivity in presence of non-specific antibiotics. Fabricated RNE electrode could detect trace amounts of spiked antigen in real samples of milk, egg and meat extract. Further, mesoporous thin film and microarrays can eventually be used to develop point-of-care diagnosis of antibiotics in animal-based food products.

Nano-modified screen-printed electrode-based electrochemical immunosensors for oral cancer biomarker detection in undiluted human serum and saliva samples

This proposed work reports the development of in-house made conductive ink-based screen-printed electrodes (SPEs) for label-free detection of oral cancer biomarkers. Carbon ink synthesis includes graphite powder, gum arabic, and water. The selectivity test of the fabricated SPE involves immobilizing antibodies specific to biomarkers and challenges with redox-active interference, other serum molecules, and non-target biomarkers. Three different biomarkers, cytokeratin-19 fragment (CYFRA 21-1), interleukin 8 (IL-8), and tumor protein p53 (TP-53), act as target entities for the detection of oral cancer in patients' samples (serum, N = 28, and saliva, N = 16) at an early stage. The standard technique enzyme-linked immunosorbent assay (ELISA) was employed to estimate the concentration of the biomarkers in serum and saliva samples. SPEs contain amine (-NH2) functional groups involved in covalent bonding with the carboxyl (-COOH) groups of antibody molecules. These immunosensors exhibited remarkably lower detection limits of 829.5 pg mL-1, 0.543 pg mL-1, and 1.165 pg mL-1, and excellent sensitivity of 0.935 μA mL pg-1 cm-1, 0.039 μA mL pg-1 cm-1, and 0.008 μA mL pg-1 cm-1 for CYFRA 21-1, IL-8, and TP-53 biomarkers, respectively. This sensing platform does not require any functionalization for biomolecule immobilization. Thus, it is a cost-effective, disposable, flexible, miniaturized, and sensitive strip to detect oral cancer biomarkers.

Pain-Free Alpha-Synuclein Detection by Low-Cost Hierarchical Nanowire Based Electrode

Analytical methods for the early detection of the neurodegenerative biomarker for Parkinson's disease (PD), α-synuclein, are time-consuming and invasive, and require skilled personnel and sophisticated and expensive equipment. Thus, a pain-free, prompt and simple α-synuclein biosensor for detection in plasma is highly demanded. In this paper, an α-synuclein electrochemical biosensor based on hierarchical polyglutamic acid/ZnO nanowires decorated by gold nanoparticles, assembled as nanostars (NSs), for the determination of α-synuclein in human plasma is proposed. ZnO NSs were prepared by chemical bath deposition (CBD) and decorated with electrodeposited Au nanoparticles (Au NPs). Then, electro-polymerized glutamic acid was grown and functionalized with anti-α-synuclein. A synergistic enhancement of electrode sensitivity was observed when Au NPs were embedded into ZnO NSs. The analytical performance of the biosensor was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), using the Fe(II)(CN)64-/Fe(III)(CN)63- probe. The charge transfer resistance after α-synuclein recognition was found to be linear, with a concentration in the range of 0.5 pg·mL-1 to 10 pg·mL-1, a limit of detection of 0.08 pg·mL-1, and good reproducibility (5% variation) and stability (90%). The biosensor was also shown to reliably discriminate between healthy plasma and PD plasma. These results suggest that the proposed biosensor provides a rapid, quantitative and high-sensitivity result of the α-synuclein content in plasma, and represents a feasible tool capable of accelerating the early and non-invasive identification of Parkinson's disease.

Organic Electronics in Biosensing: A Promising Frontier for Medical and Environmental Applications

The promising field of organic electronics has ushered in a new era of biosensing technology, thus offering a promising frontier for applications in both medical diagnostics and environmental monitoring. This review paper provides a comprehensive overview of organic electronics' remarkable progress and potential in biosensing applications. It explores the multifaceted aspects of organic materials and devices, thereby highlighting their unique advantages, such as flexibility, biocompatibility, and low-cost fabrication. The paper delves into the diverse range of biosensors enabled by organic electronics, including electrochemical, optical, piezoelectric, and thermal sensors, thus showcasing their versatility in detecting biomolecules, pathogens, and environmental pollutants. Furthermore, integrating organic biosensors into wearable devices and the Internet of Things (IoT) ecosystem is discussed, wherein they offer real-time, remote, and personalized monitoring solutions. The review also addresses the current challenges and future prospects of organic biosensing, thus emphasizing the potential for breakthroughs in personalized medicine, environmental sustainability, and the advancement of human health and well-being.

Mini review about metal organic framework (MOF)-based wearable sensors: Challenges and prospects

Among many types of wearable sensors, MOFs-based wearable sensors have recently been explored in both commercialization and research. There has been much effort in various aspects of the development of MOF-based wearable sensors including but not limited to miniaturization, size control, safety, improvements in conformal and flexible features, improvements in the analytical performance and long-term storage of these devices. Recent progress in the design and deployment of MOFs-based wearable sensors are covered in this paper, as are the remaining obstacles and prospects. This work also highlights the enormous potential for synergistic effects of MOFs used in combination with other nanomaterials for healthcare applications and raise attention toward the economic aspect and market diffusion of MOFs-based wearable sensors.

High-Rate One-Dimensional α-MnO2 Anode for Lithium-Ion Batteries: Impact of Polymorphic and Crystallographic Features on Lithium Storage

Manganese dioxide (MnO2) exists in a variety of polymorphs and crystallographic structures. The electrochemical performance of Li storage can vary depending on the polymorph and the morphology. In this study, we present a new approach to fabricate polymorph- and aspect-ratio-controlled α-MnO2 nanorods. First, δ-MnO2 nanoparticles were synthesized using a solution plasma process assisted by three types of sugars (sucrose, glucose, and fructose) as reducing promoters; this revealed different morphologies depending on the nucleation rate and reaction time from the molecular structure of the sugars. Based on the morphology of δ-MnO2, the polymorphic-transformed three types of α-MnO2 nanorods showed different aspect ratios (c/a), which highly affected the transport of Li ions. Among them, a relatively small aspect ratio (c/a = 5.1) and wide width of α-MnO2-S nanorods (sucrose-assisted) induced facile Li-ion transport in the interior of the particles through an increased Li-ion pathway. Consequently, α-MnO2-S exhibited superior battery performance with a high-rate capability of 673 mAh g-1 at 2 A g-1, and it delivered a high reversible capacity of 1169 mAh g-1 at 0.5 A g-1 after 200 cycles. Our findings demonstrated that polymorphs and crystallographic properties are crucial factors in the electrode design of high-performance Li-ion batteries.

An Integrated Approach to Improve the Assay Performance of Quantum Dot-Based Lateral Flow Immunoassays by Using Silver Deposition

Traditional quantum dot-based lateral flow immunoassay (QD-LFIA) is limited to signal loss in part by the blinking, photobleaching and oxidative quenching of QD probes. Inspired by the good application of silver deposition on QD surfaces in tissue imaging, and in the context of improving the assay performance without compromising the simplicity and practicality, we report that introducing the QD-silver combination to the LFIA system, has the advantages of accuracy improvement, signal enhancement and user friendliness promotion, but maintains the cost-effective property and commercial accessibility of QD-LFIA. The effect was shown by using CdSe/ZnS QD-LFIA coupled with anti-sodium pentachlorophenate antibody, which provided a 4-fold improvement in the signal, a 2.5-fold improvement in the detection limit and a zero false-negative rate for sodium pentachlorophenate analysis in chicken samples. The proposed LFIA integrates the possibilities of colorimetric and fluorometric detection with different detection limits (fluorometric at 10 ng/mL and colorimetric at 4 ng/mL) and with acceptable detection times (fluorometric at 12 min and colorimetric at 27 min). The current results indicate that this QD-silver combined LFIA is complementary to conventional fluorescence LFIA and could be an inexpensive, versatile, and sensitive alternative.

Impedimetric immunosensor for microalbuminuria based on a WS2/Au water-phase assembled nanocomposite

An electrochemical impedimetric biosensor for human serum albumin (HSA) determination is proposed. The biosensor is based on water-phase assembled nanocomposites made of 2D WS₂ nanoflakes and Au nanoparticles (AuNPs). The WS₂ has been produced using a liquid-phase exfoliation strategy assisted by sodium cholate, obtaining a water-stable suspension that allowed the straightforward decoration with AuNPs directly in the aqueous phase. The resulting WS₂/Au nanocomposite has been characterized by atomic force microscopy and Raman spectroscopy and, then, employed to modify screen-printed electrodes. Good electron-transfer features have been achieved. An electrochemical immunosensing platform has been assembled exploiting cysteamine-glutaraldehyde covalent chemistry for antibody (Ab) immobilization. The resulting immunosensor exhibited good sensitivity for HSA detection (LOD = 2 ng mL^-1), with extended linear range (0.005 - 100 µg mL^-1), providing a useful analytical tool for HSA determination in urine at relevant clinical ranges for microalbuminuria screening. The HSA quantification in human urine samples resulted in recoveries from 91.8 to 112.4% and was also reproducible (RSD < 7.5%, n = 3), with marked selectivity. This nanocomposite, thanks to the reliable performance and the ease of the assembling strategy, is a promising alternative for electrochemical immunosensing of health relevant markers.

A simple, sensitive, label-free electrochemical immunosensor based on the chitosan-coated silver/cerium oxide (CS@Ag/CeO2) nanocomposites for the detection of alpha-fetoprotein (AFP)

Metal oxide-based sensors have the benefit of inexpensive, quick response, and high sensitivity in detecting specific biological species. In this article, a simple electrochemical immunosensor was fabricated using antibody-chitosan coated silver/cerium oxide (Ab-CS@Ag/CeO₂) nanocomposites on a gold electrode for sensitive alpha-fetoprotein (AFP) diagnosis in human serum samples. Successfully synthesis of AFP antibody-CS@Ag/CeO₂conjugates was confirmed through Fourier transform infrared spectra of the prototype. The amine coupling bond chemistry was then used to immobilize the resultant conjugate on a gold electrode surface. It was observed that the interaction of the synthesized Ab-CS@Ag/CeO₂nanocomposites with AFP prevented an electron transfer and reduced the voltammetric Fe(CN)₆^3-/4-peak current, which was proportional to the amount of AFP. The linear ranges of AFP concentration were found from 10^-12-10^-6g.ml^-1. The limit of detection was calculated using the calibration curve and came out to be 0.57 pg.ml^-1. The designed label-free immunosensor successfully detected AFP in human serum samples. As a result, the resulting immunosensor is a promising sensor plate form for AFP detection and could be used in clinical bioanalysis.

Functionalized nanoparticles: Tailoring properties through surface energetics and coordination chemistry for advanced biomedical applications

Significant advances in nanoparticle-related research have been made in the past decade, and amelioration of properties is considered of utmost importance for improving nanoparticle bioavailability, specificity, and catalytic performance. Nanoparticle properties can be tuned through in-synthesis and post-synthesis functionalization operations, with thermodynamic and kinetic parameters playing a crucial role. In spite of robust functionalization techniques based on surface chemistry, scalable technologies have not been explored well. The coordination enhancement via surface functionalization through organic/inorganic/biomolecules material has attracted much attention with morphology modification and shape tuning, which are indispensable aspects in the colloidal phase during biomedical applications. It is envisioned that surface amelioration influences the anchoring properties of nano interfaces for the immobilization of functional groups and biomolecules. In this work, various nanostructure and anchoring methodologies have been discussed, aiming to exploit their full potential in precision engineering applications. Simultaneous discussions on emerging characterization strategies for functionalized assemblies have been made to gain insights into functionalization chemistry. An overview of current advances and prospects of functionalized nanoparticles has been presented, with an emphasis on controllable attributes such as size, shape, morphology, functionality, surface features, Debye and Casimir interactions.

A Systematic Review on the Advanced Techniques of Wearable Point-of-Care Devices and Their Futuristic Applications

Personalized point-of-care testing (POCT) devices, such as wearable sensors, enable quick access to health monitoring without the use of complex instruments. Wearable sensors are gaining popularity owing to their ability to offer regular and continuous monitoring of physiological data by dynamic, non-invasive assessments of biomarkers in biofluids such as tear, sweat, interstitial fluid and saliva. Current advancements have concentrated on the development of optical and electrochemical wearable sensors as well as advances in non-invasive measurements of biomarkers such as metabolites, hormones and microbes. For enhanced wearability and ease of operation, microfluidic sampling, multiple sensing, and portable systems have been incorporated with materials that are flexible. Although wearable sensors show promise and improved dependability, they still require more knowledge about interaction between the target sample concentrations in blood and non-invasive biofluids. In this review, we have described the importance of wearable sensors for POCT, their design and types of these devices. Following which, we emphasize on the current breakthroughs in the application of wearable sensors in the realm of wearable integrated POCT devices. Lastly, we discuss the present obstacles and forthcoming potentials including the use of Internet of Things (IoT) for offering self-healthcare using wearable POCT.