Biosensor Applications Research Articles

CdSe/ZnS quantum dots-doped polymer optical fiber microprobe for pH sensing

pH is an important physiological parameter within organisms, playing a crucial role in functional activities in cells and tissues. Among various pH sensing methods, optical fiber pH sensors have gained a wide attention due to their unique advantages. However, current silica optical fiber-based pH sensors face some challenges such as weak biocompatibility, low biological safety, complex or unstable surface modification. Herein, we develop what we believe to be a novel pH sensor based on a CdSe/ZnS quantum dots-doped polymer optical fiber microprobe (POF MP) grown at the end of the silica optical fiber using the free radical photopolymerization process, which has the advantages of significant compactness, high flexibility, good biocompatibility, easy functionalization, high structural stability and safety. Moreover, the size of the POF MP are controllable, which is highly significant for applications requiring specific probe sizes or those used in special terrains. The proposed sensor is demonstrated to have a sensitivity of 0.18097/pH in a wide pH range from 4.5 to 9.0, while it exhibits a highly linear correlation between fluorescence intensity and pH value (R2 = 0.99448) and good reversibility and reusability. This proposed pH sensor offers a promising solution for pH monitoring in biological environments, contributing to advancements in biosensing, microenvironment monitoring, and potential therapeutic applications.

Computational and AI‐Driven Design of Hydrogels for Bioelectronic Applications

AbstractAs hydrogel research progresses, hydrogels are becoming essential tools in bioelectronics and biotechnology. This review explores the diverse range of natural and synthetic gel materials tailored for specific bioelectronic applications, with a focus on their integration with electronic components to create responsive, multifunctional systems. The role of Artificial Intelligence (AI) in advancing gel design and functionality from optimizing material properties to enabling precise, predictive modeling is investigated. Furthermore, recent innovations that harness the synergy between hydrogels, electronics, and AI are discussed, emphasizing the potential of these materials to drive future advances in biomedical technologies. AI‐driven approaches are transforming the development of hydrogels for applications in wound healing, biosensing, drug delivery, and tissue engineering.

Polysaccharides-Directed Biomineralization of Enzymes in Hierarchical Zeolite Imidazolate Frameworks for Electrochemical Detection of Phenols.

Biomineralization of enzymes inside rigid metal-organic frameworks (MOFs) is appealing due to its biocompatibility and simplicity. However, this strategy has hitherto been limited to microporous MOFs, leading to low apparent enzymatic activity. In this study, polysaccharide sodium alginate is introduced during the biomineralization of enzymes in zeolitic imidazolate frameworks (ZIFs) to competitively coordinate with metal ions, which endows the encapsulated enzyme with a 7-fold higher activity than that in microporous ZIFs. Mechanism investigation showed that the introduction of alginate generates hierarchical porous structures and enhances the hydrophilicity, which contributes to the enhanced activity of the enzyme. Moreover, the porous ZIFs protect the embedded tyrosinase under detrimental conditions, which allows for the fast detection of phenol, with the limit of detection of 0.03 mM (S/N = 3). Engineering the enzyme with MOFs to enhance its activity and stability is anticipated to extend its application in biocatalysis and biosensors.

Bio-Based Elastomers: Design, Properties, and Biomedical Applications.

To reduce carbon footprint and human dependence on fossil fuels, the field of bio-based polymers has undergone explosive growth in recent years. Among them, bio-based elastomers have gained tremendous attention for their inherent softness, high strain, and resilience. In this review, the recent progress of representative bio-based elastomers derived from molecular building blocks and biopolymers are recapitulated, with an emphasis on molecular design, synthesis approaches, and mechanical performance. The performance-advantaged properties of bio-based elastomers, including immune modulation, biocompatibility, and biodegradability are also explored. Furthermore, their representative biomedical applications in wound dressing, cardiovascular, nerve repair, bone repair, and biosensors are exemplified. Lastly, the challenges and outlooks development of bio-based elastomers are discussed. This review aims to offer readers valuable insights into the potential of bio-based elastomers as viable alternatives to petroleum-based counterparts, supporting the transition toward a more sustainable future.

Study of Bionic Tactile Sensors in Flexible Robots

This research investigates the advancement and implementation of bio-inspired tactile and mechanosensory systems, drawing inspiration from sophisticated biological mechanisms found in nature, particularly human sensory networks and the Venus flytrap's rapid response system. The study demonstrates significant progress in developing highly sensitive and precise sensor technologies that effectively mimic natural sensing capabilities. Through innovative material combinations and structural designs, including hybrid graphene-based platforms and advanced piezoelectric tactile arrays, these sensing systems achieve enhanced detection of mechanical forces, subtle vibrations, and environmental fluctuations. The research findings indicate substantial improvements in sensor performance metrics, including response time, sensitivity threshold, and signal-to-noise ratio. Current challenges in manufacturing scalability and cost-effectiveness are addressed, with proposed solutions for large-scale production and seamless system integration. The study outlines promising applications across multiple fields, from advanced prosthetic limbs with enhanced tactile feedback to sophisticated robotic systems capable of precise environmental interaction. Future research directions emphasize the development of more robust and adaptable sensing platforms, focusing on improved durability, reduced power consumption, and enhanced integration capabilities for next-generation biosensing applications.

Gold-nanoparticle associated Deep Eutectic Solution mediates early bio detection of Ovarian Cancer

Gold nanoparticles (AuNPs) have indeed been extensively researched in biological and photothermal therapy applications in recent years. This study aims to enhance the sensitivity of biosensors for early detection of ovarian cancer biomarkers by investigating the efficacy of DES-mediated surface functionalization of AuNPs. Additionally, the impact of DES on the stability and dispersion of AuNPs on SiO2 support is assessed to optimize sensor performance. A simple DES-mediated synthesis method for efficient amine surface functionalization of silicon dioxide (SiO2) to incorporate tiny AuNPs for antibody biosensors. Physical characterization [Scanning Electron Microscope (SEM), Ultraviolet-Visible Spectrophotometer (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), and 3D Profiler] and electrical characterization (Keithley) have been done to determine the functionalization of the modified IDE surface. SEM analysis indicated the resultant nanoparticles have truncated spherical shapes. There is just a peak recorded by UV-Vis at 504-540 nm with AuNPs due to the formation of monodispersed AuNPs. When the conjugation of DES with samples is measured, the curves are identical in form, and the highest peak after conjugation has remained at 230 nm but the SPR absorption peak becomes narrower and moves toward greater wavelengths, indicating the conjugation between the molecules. Furthermore, when the DES is conjugated with AuNPs, 3-Aminopropyltriethoxysilane (APTES), antibody, and protein, the peaks gradually increased and became narrower, where O-H at 3280 cm-1, C-H at 2809 cm-1 and 2933 cm-1, CH2 at 1448 cm-1, CH3 at 1268 cm-1, C-OH at 1048 cm-1 and 1110 cm-1 and C-N+ at 844 cm-1 as analyzed by FTIR. Moreover, it can be observed that the 3D profilometer revealed a few red-colored areas, which are the portion that protrudes from the IDE surface. Based on the findings, it is possible to infer that this immunosensor does have the prospective to be used in clinical investigations for the precise detection of ovarian cancer or other biomarkers. The capacitance, transmittance, and resistivity profiles of the biosensor clearly distinguished between the antibody immobilization and the affinity binding. The presence of a DES-mediated synthetic approach increased the possibility of supporting different metal nanoparticles on SiO2 as the potential platform for biosensor applications.

Enhanced Near-Infrared Fluorescence Emission near a Graphene-Metal Hybrid Structure.

Plasmon resonance plays an important role in improving the detection of biomolecules, and it is one of the focuses of research to use metal plasmon resonance to achieve fluorescence enhancement and to improve detection sensitivity. However, the problems of nondynamic tuning and fluorescence quenching of metal plasmon resonance need to be solved. Graphene surface plasmon resonance can be dynamically controlled, and the graphene adsorption of fluorescent molecules can avoid fluorescence quenching and greatly improve the fluorescence emission intensity. The graphene-metal hybrid structure designed in this work can solve the above two problems well, and the plasmon resonance can improve the fluorescence emission efficiency of molecules on the surface of graphene and improve the sensitivity of biological detection. At the same time, graphene nanoribbons in our hybrid structure do not require patterning, which greatly lowers the threshold for graphene application in biosensing.

HCP-to-FCC Phase Transformation of Ruthenium Nanocrystals Selectively Activate Hydrogen Peroxide for Boosting Peroxidase-like Activity.

Due to the simultaneous activation of hydrogen peroxide (H2O2) and oxygen, Ru nanocrystals exhibit inherent peroxidase- and oxidase-like activities, thereby limiting their extensive application in biosensing. Phase engineering of Ru nanocrystals holds great promise for enhancing catalytic activity and selectivity but remains a challenge. Here, highly active Ru nanocrystals with a metastable face-centered cubic (fcc) structure were successfully synthesized via a facile wet-chemical method followed by an etching step, enabling selective activation of H2O2 and demonstrating promising peroxidase-like activity. Compared to the thermodynamically favored hexagonal close-packed Ru nanocrystals, the resultant fcc Ru shows an over 5-fold enhancement in the maximum reaction velocity of the peroxidase-like catalysis, while its oxidase-like performance exhibits a minor decline, indicating a transition from multienzyme activity to specificity. Theoretical calculations reveal that the phase transformation of Ru not only results in an upward shift of the d-band center to enhance H2O2 adsorption but also regulates the O-O bonding strength of H2O2 to achieve selective H2O2 activation. As a proof of concept, a colorimetric sensor based on fcc Ru nanocrystals was successfully constructed, achieving accurate and sensitive detection of organophosphorus pesticides. This work not only offers promising prospects for phase engineering of Ru nanocrystals but also highlights the significance of the Ru phase transition in hydrogen peroxide activation.

Engineered 3D DNA Crystals: A Molecular Design Perspective.

Recent advances in biomolecular self-assembly have transformed material science, enabling the creation of novel materials with unparalleled precision and functionality. Among these innovations, 3D DNA crystals have emerged as a distinctive class of macroscopic materials, engineered through the bottom-up approach by DNA self-assembly. These structures uniquely combine precise molecular ordering with high programmability, establishing their importance in advanced material design. This review delves into the molecular design of engineered 3D DNA crystals, classifying current crystal structures based on "crystal bond orientations" and examining key aspects of in-silico molecular design, self-assembly, and crystal modifications. The functionalization of 3D DNA crystals for applications in crystallization scaffolding, biocatalysis, biosensing, electrical and optical devices, as well as in the emerging fields of DNA computing and data storage are explored. Finally, the ongoing challenges are addressed and future directions to advance the field of engineered 3D DNA crystals are proposed.

Ion-Regulated Signal Amplification Optical Microfiber Interferometric DNA Sensor.

Genetic information sensors play a pivotal role in the biomedical field. The detection of deoxyribonucleic acid (DNA) is achieved experimentally using an optical microfiber interferometric sensor, which operates based on an ion-regulation sensitivity enhancement mechanism. The optical microfiber is fabricated by drawing optical fiber into a diameter of less than 10 μm via the melting and tapering technique. Leveraging the characteristics of monovalent cations can effectively promote the folding of G-rich single-stranded DNA (ssDNA) into stable G-quadruplex structures, enabling the detection of specific sequences of ssDNA at low concentrations. The results show an improvement of the linear detection range by 3 orders of magnitude, and with the introduction of the ion-regulation sensitivity enhancement mechanism, the limit of detection (LOD) value is 1.07 × 10-15 M. This optical microfiber interferometric sensing architecture is characterized by its simplicity and high sensitivity, positioning it as a formidable tool for diverse biosensing and analytical applications.

Preparation of polyhydroxyalkanoate nanocomposites for biomedical applications

AbstractPolyhydroxyalkanoates (PHAs) have been recognized as potential replacements for fossil fuel‐based, non‐biodegradable plastics. PHAs exhibit properties that are analogous to those of synthetic plastics. The production of PHAs offers a multitude of advantages, primarily due to their biodegradability and biocompatibility. The most naturally occurring form of PHAs are the polyhydroxybutyrates (P(3HB)s). The major limitations of P(3HB)s are their brittle nature and inferior mechanical properties. Hence, these biopolymers have been observed to have limited biotechnological applications. In contrast to P(3HB)s, copolymers of PHAs have almost all the desirable properties, making them suitable for high‐end applications such as those in the medical sector. Structural modifications in PHA molecules have expanded the scope of their applications, including in medical implants, wound healing and bone grafts. It is noteworthy that considerable progress has been made in the field of PHA nanocomposites, which are now being explored for their biotechnological applications in drug delivery, tissue engineering and biosensors. The prospects for PHA nanocomposites are also summarized. © 2025 Society of Chemical Industry.

Electrophysiological dissection of the ion channel activity of the Pseudomonas aeruginosa ionophore protein toxin Tse5.

We present an in-depth electrophysiological analysis of Tse5, a pore-forming toxin (PFT) delivered by the type VI secretion system (T6SS) of Pseudomonas aeruginosa. The T6SS is a sophisticated bacterial secretion system that injects toxic effector proteins into competing bacteria or host cells, providing a competitive advantage by disabling other microbes and modulating their environment. Our findings highlight the dependency of Tse5 insertion on membrane charge and electrolyte concentration, suggesting an in vivo effect from the periplasmic space. Conductance and selectivity experiments reveal a predominant and reproducible pore architecture of Tse5, characterized by a weak cation selectivity without chemical specificity. pH titration experiments suggest a proteolipidic pore structure influenced by both protein and lipid charges, a hypothesis further supported by experiments involving engineered mutants of Tse5 with altered glycine zippers. These results significantly advance our understanding of Tse5's molecular mechanism of toxicity, paving the way for potential applications in biosensing and macromolecular delivery.

Full-color peptide-based fluorescent nanomaterials assembled under the control of amino acid doping.

Peptide-based biofluorescents are of great interest due to their controllability and biocompatibility, as well as their potential applications in biomedical imaging and biosensing. Here, we present a simple approach to synthesizing full-color fluorescent nanomaterials with broad-spectrum fluorescence emissions, high optical stability, and long fluorescence lifetimes. By doping amino acids during the enzyme-catalyzed oxidative self-assembly of tyrosine-based peptides, we can precisely control the intermolecular interactions to obtain nanoparticles with fluorescence emission at different wavelengths. The synthesized peptide-based fluorescent nanomaterials with excellent biocompatibility and stable near-infrared fluorescence emission were shown to have potential for bioimaging applications. This research provides new ideas for the development of new bioluminescent materials that are cost-effective, environmentally friendly, and safe for biomedical use.

Advances in precise synthesis of metal nanoclusters and their applications in electrochemical biosensing of disease biomarkers.

Metal nanoclusters (NCs), comprising tens to hundreds of metal atoms, are condensed matter with concrete molecular structures and discrete energy levels. Compared to metal atoms and nanoparticles, metal NCs exhibit unique physicochemical properties, especially fascinating electrocatalytic activities. This review focuses on recent progress in the precise synthesis of metal NCs and their applications in electrochemical analysis of various disease biomarkers. First, we provide a brief overview of current nanotechnology-enabled electrochemical biosensors. Subsequently, we highlight the precise synthesis of metal NCs protected by various ligands such as peptides, proteins and nucleic acids. Next, we summarize the design and construction of electrochemical biosensors that utilize metal NCs as electrode materials to detect electrochemically active and inactive disease-associated biomarkers, including small biomolecules (glucose, reactive oxygen species, cholesterol, neurotransmitters and amino acids) and biomacromolecules (proteins, enzymes, and nucleic acids). Due to unique electrocatalytic properties, high specific surface areas, and atomically modulated structures, metal NCs promote electron exchange or act as a redox medium in these electrochemical sensing platforms. Finally, we conclude with present challenges and propose future research directions, with the aim to enhance the specificity, sensitivity, and durability of customized metal NC-based electrochemical biosensors for precise disease diagnostics.

A Concise Review on Magnetic Nanoparticles: Their Properties, Types, Synthetic Methods, and Current Trending Applications

: In recent years, there has been significant research on developing magnetic nanoparticles (MNPs) with multifunctional characteristics. This review focuses on the properties and various types of MNPs, methods of their synthesis, and biomedical, clinical, and other applications. These syntheses of MNPs were achieved by various methods, like precipitation, thermal, pyrolysis, vapor deposition, and sonochemical. MNPs are nano-sized materials with diameters ranging from 1 to 100 nm. The MNPs have been used for various applications in biomedical, cancer theranostic, imaging, drug delivery, biosensing, environment, and agriculture. MNPs have been extensively researched for molecular diagnosis, treatment, and therapeutic outcome monitoring in a range of illnesses. They are perfect for biological applications, including cancer therapy, thrombolysis, and molecular imaging, because of their nanoscale size, surface area, and absence of side effects. In particular, MNPs can be used to conjugate chemotherapeutic medicines (or) target ligands/proteins, making them beneficial for drug delivery. However, up until that time, some ongoing issues and developments in MNPs include toxicity and biocompatibility, targeting accuracy, regulation and safety, clinical translation, hyperthermia therapy, immunomodulatory effects, multifunctionality, and nanoparticle aggregation.

Electrical, Optical & Structural characteristics of reduced graphene oxide: A comparative analysis using different reducing agents

The study of optical and electrical properties of functionalised materials of GO and rGO are crucial for their different applications in energy storage, optoelectronics and biosensing. The structural disorder occurring during the synthesis process largely affects the optical properties of the materials. In this work we have tried to study the variation in optical and electrical properties of rGO by varying the synthesis parameters. Different rGO samples prepared from the same precursor (graphite powder) by using various reducing agents are studied. It is observed that the physical conditions during the synthesis process affect the bandgap of the synthesised samples. This study is correlated with the elemental analysis, surface morphology and defect studies.

Regulation of transmembrane current through modulation of biomimetic lipid membrane composition.

Ion transport through biological channels is influenced not only by the structural properties of the channels themselves but also by the composition of the phospholipid membrane, which acts as a scaffold for these nanochannels. Drawing inspiration from how lipid membrane composition modulates ion currents, as seen in the activation of the K+ channel in Streptomyces A (KcsA) by anionic lipids, we propose a biomimetic nanochannel system that integrates DNA nanotechnology with two-dimensional graphene oxide (GO) nanosheets. By modifying the length of the multibranched DNA nanowires generated through the hybridization chain reaction (HCR) and varying the concentration of the linker strands that integrate these DNA nanowire structures with the GO membrane, the composition of the membrane can be effectively adjusted, consequently impacting ion transport. This method provides a strategy for developing devices with highly efficient and tunable ion transport, suitable for applications in mass transport, environmental protection, biomimetic channels, and biosensors.

Nanomaterials for biosensing and imaging applications: Graphene and its derivatives

Nanomaterials for biosensing and imaging applications: Graphene and its derivatives

Aptamer-functionalized nucleic acid nanotechnology for biosensing, bioimaging and cancer therapy.

Nucleic acids have enabled the fabrication of self-assemblies and dynamic operations. Among different functional nucleic acids, aptamers can specifically bind to a wide range of targets, including proteins, viral antigens, living cells and even tissues, and have thus emerged as molecular recognition tools in molecular medicine. Hence, aptamer-functionalized nucleic acid nanotechnology offers applications of biosensing, bioimaging, and cancer therapy. In this review, after a brief overview of nucleic acid nanotechnology, we focus on the integration of aptamers with nucleic acid nanotechnology, including self-assembly constructions and dynamic molecular manipulations. The emerging applications in molecular medicine are subsequently reviewed with aptamer-based self-assemblies and aptamer-involved dynamic molecular manipulation. For convenience, applications are broadly categorized into biosensing, bioimaging, and cancer therapy. Finally, challenges and potential development of nucleic acid nanotechnology are discussed.

Physical and Electrochemical Characterization of Functionalized Multiwall Carbon Nanotubes Embedded with Polypyrrole/Gold Nanoparticles

In this study, the indium tin oxide (ITO) electrode was modified, physical and electrochemical characterization were studied to be used in some biosensor applications. Using the drop-casting method, functionalized Multiwall Carbon Nanotubes, Polypyrrole, and gold nanoparticles (f-MWCNTs-AuNP-PPy) were efficiently coated on the surface of an ITO electrode. Fourier transform of infrared radiation (FTIR) and field emission scanning electron microscopy (FE-SEM) were utilized to describe the microscopic structure and morphogenesis of the generated films at the ITO electrode's surface. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to assess the electroanalytical performance of electrodes after modification. The f-MWCNTs-AuNPs-PPy distribution on the ITO electrode was improved by studying the effect of adding gold nanoparticles and varying polymer concentrations on the film distribution. Electrodes were tested with bare ITO electrodes as well as electrodes modified with f-MWCNTs, f-MWCNTs-PPy, and f-MWCNTs-AuNPs-PPy. The results revealed that nanoparticles distributed on the surface of the modified electrode reduced its impedance by roughly 40% for f-MWCNTs, 75% for f-MWCNTs-PPy, and 95% for f-MWCNTs-PPy-AuNPs. The equivalent circuit was appropriately matched in three situations (f-MWCNTs, f-MWCNTs-PPy, and f-MWCNTs-PPy-AuNPs). The transmission line model, which shows the impedance sensitivity of a diffusion process was utilized to describe the film properties. Nanoparticles enhance electrochemical performance by increasing electrochemical active surface area and allowing electron transport from the redox probe (Ferrocene/ Ferrocenium) to the ITO electrode.