Dopamine Solution Research Articles

Uptake of Magnetite Nanoparticles on Polydopamine Films Deposited on Gold Surfaces: A Study by AFM and XPS.

Polydopamine has the capacity to adhere to a large variety of materials and this property offers the possibility to bind nanoparticles to solid surfaces. In this work, magnetite nanoparticles were deposited on gold substrates coated with polydopamine films. The aim of this work was to investigate the effects of the composition and morphology of the PDA layers on the sticking of magnetite nanoparticles. The polydopamine coating of gold surfaces was achieved by the oxidation of alkaline solutions of dopamine with various reaction times. The length of the reaction time to form PDA was expected to influence the composition and surface roughness of the PDA films. Magnetite nanoparticles were deposited on these polydopamine films by immersing the samples in aqueous dispersions of nanoparticles. The morphology at the nanometric scale and the composition of the surfaces before and after the deposition of magnetite nanoparticles were investigated by means of AFM and XPS. We found that the amount of magnetite nanoparticles on the surface did not vary monotonically with the reaction time of PDA formation, but it was at the minimum after 20 min of reaction. This behavior may be attributed to changes in the chemical composition of the coating layer with reaction time.

The synthesis of polydopamine nano- and microspheres in microdroplets.

Here we developed a microdroplet-based strategy for the rapid synthesis of uniform polydopamine nano- and microspheres. Polydopamine spheres with controllable sizes were generated within hundreds of microseconds by simply spraying water solutions of dopamine into microdroplets. Mass spectrometry revealed that dopamine was primarily oxidized into aminochrome, acting as the major building block for polydopamine. We anticipate that microdroplet chemistry will be rich in opportunities for the synthesis of functional nano- and micromaterials.

Polydiacetylene Liposome-Based Dual-Output Optical Sensor for ppb Level Detection of Dopamine in Solution and Solid Phases.

Dopamine (DA), a neurotransmitter, plays a crucial role in regulating motor functions and emotions and can serve as a marker for several diseases. In this study, we report a highly sensitive polydiacetylenes (PDA)-based dual-output sensor for dopamine detection in both solution and solid phases that was developed by modifying PDA liposomes with boronic acid groups at the termini. This sensor exploits the high affinity between the catechol residue of dopamine and the -B(OH)2 group of the PDA-based probe (PDA-PhBA) to form boronate ester bonds, causing a stress-induced blue-to-red color change along with a steady increase in fluorescence response at λmax 622 nm. The PDA-PhBA-based sensor displays high sensitivity toward dopamine with low limit of detection of 6.2 ppb in colorimetric analysis and 0.6 ppb in fluorimetric measurements, demonstrating its dual optical output ability. The sensor works well for adrenaline, another catecholamine, with similar efficacy. Its practical applicability was validated by the successful recovery of trace level dopamine in blood serum and real water samples. Additionally, immobilizing PDA-PhBA liposomes in sodium alginate produced PDA beads for the solid-phase detection of dopamine with an limit of detection (LOD) of 59 nM (9.0 ppb) in colorimetric detection using a smartphone for capturing images and ImageJ software for analysis.

Enhancing adhesion and durability: A biomimetic approach with dopamine-modified lignin-polydimethylsiloxane coatings

Corrosion causes significant challenges in industrial settings, leading to economic losses and safety concerns. Previously, we developed a lignin-polydimethylsiloxane (lignin-PDMS) coating that exhibited high corrosion resistance. However, the adhesion of the developed lignin-PDMS coating to carbon steel was limited, affecting its overall performance. To address this, we incorporated dopamine (DOPA), known for its strong adhesive properties, as a pre-treatment before applying the coating. It was found that the adhesion and corrosion resistance of lignin-PDMS coated steel could be improved by adjusting the pH value of the DOPA solution. The steel treated with pH 4.5 DOPA solution showed two times higher adhesion strength to the coating than non-treated steel. After the DOPA treatment, the coating can maintain high barrier property for at least 3 months in 1 M NaCl solution, which is even better than commercial gelcoat, demonstrating super corrosion protection. Quartz Crystal Microbalance with Dissipation (QCM-D) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed the DOPA deposition on the steel surface. Our findings show that the DOPA-lignin-PDMS system is an environmentally friendly and efficient solution for enhancing the durability of steels in corrosive environments.

Conferring NiTi alloy with controllable antibacterial activity and enhanced corrosion resistance by exploiting Ag@PDA films as a platform through a one-pot construction route

The lack of antibacterial activity and the leaching of Ni ions seriously limit the potential applications of the near equiatomic nickel-titanium (NiTi) alloy in the biomedical field. In this study, a silver nanoparticles (Ag NPs) wrapped in a polydopamine (Ag@PDA) film modified NiTi alloy with controllable antibacterial activity and enhanced corrosion resistance was achieved using a one-pot approach in a mixed solution of AgNO3 and dopamine. The controllable antibacterial activity could be achieved by adjusting the initial concentration of dopamine (Cdop), which obtained Ag@PDA films with varying thickness of polydopamine layers coated on Ag NPs, thereby conferring different levels of antibacterial activity to the modified NiTi alloy. In vitro antibacterial ratios (24 h) of Ag@PDA film-modified NiTi alloy against E.coli and S.aureus ranged from 46 % to 100 % and from 42 % to 100 %, respectively. The release curves of Ag ions indicated the persistent antibacterial effect of Ag@PDA film-modified NiTi alloy for at least 21 days. Moreover, in vitro cytotoxicity and in vivo implantation tests demonstrated the satisfactory biosafety of the Ag@PDA film-modified NiTi alloy when used as bioimplants. This research offers valuable insight into meeting various antibacterial demands for NiTi alloy implantations and highlights the potential of Ag-containing film-modified biomaterials in addressing different types of infections induced by implantations.

Convenient and Accurate Detection of Dopamine and Glucose by Modifying Carbon Fiber Electrodes

Fast, sensitive, and low-cost high-performance detectors have gradually become an indispensable tool for people to keep healthy, and sensors are the key devices of detection equipment. In this work, a ZnO nanocrystal modified carbon fiber electrode was prepared using a hydrothermal method, and on this basis, a galvanostatic point deposition method was used to load copper nanoparticles to prepare a sensor electrode. Scanning electron microscopy and X-ray diffraction were used to comprehensively analyze composition, morphology, and environmental adaptability of the prepared electrodes. The DPV test was used to verify the enhanced effect of ZnO nanorods on neurotransmitter detection. The ZnO/CF showed an obvious electrical signal (0.22 V, 4 × 10−5A) in the detection of dopamine (DA) solution, and the Cu-NPs/ZnO/CF also showed excellent detection results in the glucose detection experiment., providing two excellent examples for the development of low-cost electrochemical sensors. The electrodes can specifically detect DA in the presence of ascorbic acid and uric acid, and the detection limit of the electrode for detecting DA is about 0.4 μM. In addition, the Cu-NPs/ZnO/CF electrode successfully realized the enzyme-free detection of glucose, and the detection limit could reach 0.5 μM.

Functionalized Blood Small Extracellular Vesicles with Polydopamine Nanoparticles for Chemo-Thermal Therapy.

Small extracellular vesicles (sEVs) hold considerable promise for drug delivery due to their natural origin and inherent qualities. However, their clinical application is impeded by two main challenges: low yield and potential side effects. Therefore, it is crucial to obtain substantial quantities of sEVs that adhere to rigorous biosafety standards to ensure successful translation into clinical practice. To address this need, we propose exploring optimized methods for sourcing and separating sEVs, taking inspiration from clinical blood transfusion. In particular, we have identified blood sEVs as a viable alternative and developed a novel separation technique for their isolation. Our approach involves incubating dopamine solution with serum, resulting in the formation of polydopamine (PDA) nanoparticles on the surface of blood sEVs. These nanoparticles have minimal impact on blood sEVs, facilitating their easy separation under standard centrifugal conditions with high purity. This innovative technique enables the development of nanocarriers using blood sEVs with efficient drug-loading capabilities and enhanced pharmacokinetics. Additionally, the incorporation of PDA nanoparticles imparts a photothermal effect to the nanomedicines, enabling the integration of chemotherapy and photothermal therapy. Moreover, the photothermal effect holds the potential to facilitate the membrane fusion of sEVs and cells. In summary, our straightforward surface functionalization technique utilizing PDA effectively isolates blood sEVs and enables chemo-thermal tumor therapy. This approach significantly enhances the feasibility of translating sEV-based nanomedicines into clinical applications.

Enhancing bioactivity and biocompatibility of polyetheretherketone (PEEK) for dental and maxillofacial implants: A novel sequential soaking process

Polyetheretherketone (PEEK) exhibits excellent biocompatibility, fatigue resistance, and an elastic modulus similar to bone, presenting broad application prospects in the field of dental and maxillofacial implants. However, the bioinertness of PEEK limits its applications. In this study, we developed a method to generate biocompatible and bioactive PEEK through a simple sequential soaking process, aimed at inducing bone differentiation and enhancing antibacterial properties. Initially, a three-dimensional (3D) porous network was introduced on the PEEK surface by soaking in concentrated sulfuric acid and water. Subsequently, the sulfonated PEEK surface was treated with oxygen plasma, followed by immersion in a dopamine solution to coat a polydopamine (PDA) layer. Finally, polydopamine phosphate ester-modified 3D porous PEEK was obtained through the reaction of phosphoryl chloride with surface phenolic hydroxyl groups. Systematic studies were conducted using scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle analysis, cell proliferation and adhesion, osteogenic gene expression detection, alkaline phosphatase staining, alizarin red staining, and bacterial culture. Overall, compared to unmodified PEEK, the modified PEEK significantly enhanced in vitro cell proliferation and adhesion, osteogenic differentiation, and antibacterial properties. The simple surface modification measures combined in this study may represent a promising technology and could facilitate the application of PEEK in dental and maxillofacial implants.

Ultrathin and Smooth Pheomelanin-like Photoconductive Film.

This study introduces a facile method for the substrate-independent deposition of pheomelanin-like films, revealing unique and promising electrical characteristics. The conventional darkening of a dopamine solution at a basic pH was significantly delayed by the addition of l-cysteine, resulting in a distinctive temporal pattern: an initial quiescent period without apparent color change followed by an abrupt and explosive burst. Surprisingly, within the quiescent period, the deposition of ultrathin and smooth pheomelanin-like films was observed, in addition to rough and thick films formed after the burst. Regardless of thickness or texture, these films exhibited common chemical properties, including moisture-capturing capability and dark- and bright-state conductivities. Particularly noteworthy were consistent photocurrent responses under bias voltage across various pheomelanin-like films, which were not observed in polydopamine films, highlighting the influential role of l-cysteine addition. These findings present a novel avenue for the potential application of pheomelanin-like films in bioelectronics, emphasizing their distinct electrical characteristics and prompting further exploration into their intricate conductive mechanisms. The study contributes to advancing our understanding of melanin-based materials and their potential in diverse scientific and technological domains.

Exogenous dopamine mitigates the effects of salinity stress in tomato seedlings by alleviating the oxidative stress and regulating phytohormones

Salt stress is a worldwide major threat to agricultural production. The aim was to investigate the effects of exogenous dopamine (DA) treatments on physiological, morphological and biochemical characteristics of tomato seedlings under salinity stress. Salt stress was created using a 100 mM NaCl solution. Dopamine solutions (0, 50, 100 and 200 µM) were applied with 7-day intervals. Salt stress significantly suppressed plant growth and DA treatments alleviated the negative effects of salt stress on the growth of tomato seedlings. 100 µM DA treatment increased plant and root dry weights, plant stem diameter, plant height and, leaf area by 286.84%, 150.00%, 108.37%, 160.89%, and 158.28%, respectively, compared to the control. Under salinity LRWC, SPAD, chl-a, chl-b, and total chlorophyll contents decreased; membrane permeability (MP), H2O2, MDA, proline and sucrose contents, CAT, POD and SOD activities increased. Under salt stress, when 100 µM DA was applied, LRWC, SPAD, chl-a, chl-b, and total chlorophyll contents of plants increased by 13.64%, 18.62%, 43.08%, 64.90%, and 50.00%, while MP reduced by 21.08% compared to the control. When 200 µM DA was applied under salt stress, H2O2, MDA, proline and sucrose contents, and CAT, POD and SOD activities were reduced by 31.86%, 18.66%, 56.00%, 38.24%, 11.16%, 17.81% and 10.80%, respectively, compared to non-DA-treated plants. Exogenous application of DA increased IAA content, decreased ABA content and increased ratio of K+/Na+ and Ca2+/Na+ under salt stress as well. In conclusion, exogenous dopamine treatments effectively prevent cellular damage in tomato seedlings and improve plant tolerance to salt stress.

Fabrication of high-flux PTFE hollow fiber membranes through nonionic surfactant infiltration coupled with mussel-inspired chemistry coating

Polytetrafluoroethylene (PTFE) hollow fiber membrane holds tremendous potential for the treatment of complex wastewater due to its outstanding chemical and thermal stability. However, its treatment efficiency is often hindered by the low water permeate flux arising from the inherent hydrophobicity of PTFE. Here, we present a gentle and convenient hydrophilic modification method that involves immersion in a nonionic surfactant aqueous solution, followed by dopamine self-polymerization. The nonionic surfactant facilitated the penetration of the dopamine solution into the membrane, where dopamine self-polymerized to form a hydrophilic layer on the surface and inner pores of the membrane. The hydrophilicity-modified PTFE hollow fiber membranes demonstrated an impressive increase in water permeate flux, reaching 10231.4 L m−2 h−1, nearly ten times that of the original membrane. Even after prolonged exposure to a strong acid solution (pH = 1) or an oxidant solution (1000 mg L−1 NaClO) for two weeks, this membrane still maintained its favorable water permeability. Furthermore, the modified PTFE membranes also exhibited remarkable resistance to fouling by humic acid. These results showcased a straightforward method for designing a hydrophilic layer on PTFE hollow fiber membranes, underscoring their significant potential for real wastewater treatment applications.

Superhydrophilic conformal polydopamine coating on nanostructured surface formed by capillary-induced solution infusion

As a material-independent adhesive coating agent with excellent functionality on interfaces of materials, polydopamine (PDA) has been widely applicable in bioengineering, environment, and energy fields. Conventional coating methods using dopamine (DA) solutions suffer from slow deposition rates, hindering the attainment of adequate thickness and durability. This work introduces a technique involving rapid capillary-induced solution infusion and in-air polymerization to overcome these limitations. By immersing nanostructured surfaces for just 10 s into the solution, the DA solution is uniformly infused onto the surface, and distributed evenly over the nanostructured surfaces. Polymerization is facilitated by oxygen diffusion from the air, resulting in the formation of a conformal coating up to a micrometer thick. These PDA coatings exhibit persistent superhydrophilicity with water contact angle below 10° and maintain resistance to abrasion, sonication, and oil fouling. Additionally, when applied to microfiber textiles, the PDA coating leads to excellent underwater oil repellency. Our method holds promise for compatibility with various wet-based coating techniques such as drop casting, spraying, spin coating, or ink-jet printing, opening avenues for versatile applications in diverse fields.

A modified Prussian blue biosensor with improved stability based on the use of self-assembled monolayers and polydopamine for quantitative L-glutamate detection.

Aminiature L-glutamate (L-Glu)biosensor is describedbased on Prussian blue (PB) modification with improved stability by using self-assembled monolayers (SAMs) technology and polydopamine (PDA). A gold microelectrode (AuME) was immersed in NH2(CH2)6SH-ethanol solution, forming well-defined SAMs via thiol-gold bonding chemistry which increased the number of deposited Prussian blue nanoparticles (PBNPs) and confined them tightly on the AuME surface. Then, dopamine solution was dropped onto the PBNPs surface and self-polymerized into PDA to protect the PB structure from destruction. The PDA/PB/SAMs/AuME showed improved stability through CV measurements in comparison with PB/AuME, PB/SAMs/AuME, and PDA/PB/AuME. The constructed biosensor achieved a high sensitivity of 70.683 nAµM-1cm-2 in the concentrationrange 1-476µM L-Gluwith a low LOD of 0.329µM and performed well in terms of selectivity, reproducibility, and stability. In addition, the developed biosensor was successfully applied to the determination of L-Glu in tomato juice, and the results were in good agreement with that of high-performance liquid chromatography (HPLC). Due to its excellent sensitivity, improved stability, and miniature volume, the developed biosensor not only has a promising potential for application in food sample analysis but also provides a good candidate for monitoring L-Glu level in food production.

Enhancing the mechanical properties of basalt fiber/nylon 6 composites by surface roughening and hydrogen bonding interaction

AbstractInspired by the strong adhesion of mussels, basalt fibers (BFs) were modified with polydopamine and then composited with nylon 6. The effect of polydopamine content on the interfacial interactions and mechanical properties of the composites was investigated. In addition, silica nanoparticles were grown on the surface of polydopamine‐modified BFs to investigate the synergistic effect. The study revealed that the mechanical properties of the composites based on polydopamine‐modified BF were gradually enhanced with the increase of the dopamine coverage concentration, and gradually decreased after reaching the peak. 0.5 g/L concentration of dopamine solution modified BFs showed the best enhancement effect on nylon 6, and its tensile strength could reach 133.1 MPa, which was 28.5% higher than that of the unmodified composites. The tensile strength of the composites modified with both dopamine and silica nanoparticles reached 157 MPa, which was 51.7% higher than that of the unmodified composites. In addition, scanning electron microscope images of fracture sections confirmed the strong interfacial interaction between BF and PA6.Highlights The surface roughness of BF was increased by nano‐SiO2. Hydrogen bonding was formed between PDA and PA6. Physical interlock was formed between nano‐SiO2 and PA6. Tensile strength increased by 51.7% with both nano‐SiO2 and PDA. Stronger interfacial interaction leads to higher thermal stability.

Novel Approach for the Immobilization of Cellobiose Dehydrogenase in PEDOT:PSS Conductive Layer on Planar Gold Electrodes

Third-generation biosensors use enzymes capable of direct electron transfer (DET) to the sensor surface. They are of interest for continuous glucose monitoring in blood or interstitial fluid, but they are rarely investigated. One reason is the hindered DET of the enzymes to the metallic electrodes. In this publication, a novel method for the immobilization of cellobiose dehydrogenase (CDH) DET enzymes employing conductive poly(3,4-ethylenedioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS) inks and a protective polyethylene glycol dimethacrylate (PEG-DMA) hydrogel layer on gold electrodes is reported. This layer stack showed a glucose-specific current response for voltages between −0.2 and 0.4 V in physiological PBS buffer, and enabled interference-less sensing in a solution of acetaminophen, ascorbic acid, dopamine, and uric acid at 0 V. A Michaelis–Menten fit led to a maximum current density (Imax) of 257 ± 7.9 nA/mm2 and a Michaelis–Menten constant (Km) of 28.4 ± 2.2 mM, with a dynamic range of 0.1–20 mM glucose and a limit of detection of 0.1 mM. After 16 h of continuous measurement of 20 mM glucose, the signal decreased to 60% of its initial value. Storage stability was successfully verified until up to 10 days. In summary, this paper shows a simplified approach for the fabrication of third-generation biosensors using CDH-PEDOT:PSS and PEG-DMA hydrogel inks.

A Facile Surface Modification Scheme for Medical-Grade Titanium and Polypropylene Using a Novel Mussel-Inspired Biomimetic Polymer with Cationic Quaternary Ammonium Functionalities for Antibacterial Application.

Medical device-associated infection remains a critical problem in the healthcare setting. Different clinical- or device-related methods have been attempted to reduce the infection rate. Among these approaches, creating a surface with bactericidal cationic functionality has been proposed. To do so, a sophisticated multi-step chemical procedure would be needed. Instead, a simple immersion approach was utilized in this investigation to render the titanium and polypropylene surface with the quaternary ammonium functionality by using a mussel-inspired novel lab-synthesized biomimetic catechol-terminated polymer, PQA-C8. The chemical oxidants, CuSO4/H2O2, as well as dopamine, were added into the novel PQA-C8 polymer immersion solution for one-step surface modification. Additionally, a two-step immersion scheme, in which the polypropylene substrate was first immersed in the dopamine solution and then in the PQA-C8 solution, was also attempted. Surface analysis results indicated the surface characteristics of the modified substrates were affected by the immersion solution formulation as well as the procedure utilized. The antibacterial assay has shown the titanium substrates modified by the one-step dopamine + PQA-C8 mixtures with the oxidants added and the polypropylene modified by the two-step scheme exhibited bacterial reduction percentages greater than 90% against both Gram-positive S. aureus and Gram-negative E. coli and these antibacterial substrates were non-cytotoxic.

Morphological hallmarks of dopaminergic neurodegeneration are associated with altered neuron function in Caenorhabditis elegans

Caenorhabditis elegans (C. elegans) is an excellent model system to study neurodegenerative diseases, such as Parkinson’s disease, as it enables analysis of both neuron morphology and function in live animals. Multiple structural changes in neurons, such as cephalic dendrite morphological abnormalities, have been considered hallmarks of neurodegeneration in this model, but their relevance to changes in neuron function are not entirely clear. We sought to test whether hallmark morphological changes associated with chemically induced dopaminergic neuron degeneration, such as dendrite blebbing, breakage, and loss, are indicative of neuronal malfunction and result in changes in behavior. We adapted an established dopaminergic neuronal function assay by measuring paralysis in the presence of exogenous dopamine, which revealed clear differences between cat-2 dopamine deficient mutants, wildtype worms, and dat-1 dopamine abundant mutants. Next, we integrated an automated image processing algorithm and a microfluidic device to segregate worm populations by their cephalic dendrite morphologies. We show that nematodes with dopaminergic dendrite degeneration markers, such as blebbing or breakage, paralyze at higher rates in a dopamine solution, providing evidence that dopaminergic neurodegeneration morphologies are correlated with functional neuronal outputs.

Mussel-Inspired Calcium Alginate/Polyacrylamide Dual Network Hydrogel: A Physical Barrier to Prevent Postoperative Re-Adhesion.

Intrauterine adhesions (IUA) has become one of the main causes of female infertility. How to effectively prevent postoperative re-adhesion has become a clinical challenge. In this study, a mussel-inspired dual-network hydrogel was proposed for the postoperative anti-adhesion of IUA. First, a calcium alginate/polyacrylamide (CA-PAM) hydrogel was prepared via covalent and Ca2+ cross-linking. Benefiting from abundant phenolic hydroxyl groups, polydopamine (PDA) was introduced to further enhance the adhesion ability and biocompatibility. This CA-PAM hydrogel immersed in 10 mg/mL dopamine solution possessed remarkable mechanical strength (elastic modulus > 5 kPa) and super stretchability (with a breaking elongation of 720%). At the same time, it showed excellent adhesion (more than 6 kPa). Surprisingly, the coagulation index of the hydrogel was 27.27 ± 4.91, demonstrating attractive coagulation performance in vitro and the potential for rapid hemostasis after surgery.

Polydopamine-modified magnetic foam composites synergistically activate peroxymonosulfate with visible light for sulfadiazine degradation and oil–water separation

This study used a CuSO4/H2O2 catalyst to accelerate the oxidation and polymerization of dopamine in solution to facilitate the rapid deposition of polydopamine (PDA) onto a melamine foam. Dopamine provided the Fe3O4 adhesive layer and additional photocatalytic electron transfer channels for the foam. Stearic acid (SA) was used as the final incorporation on the surface of melamine foam(MF) to further superhydrophobically modify the magnetic foam (MF@PDA/Fe3O4) to obtain superhydrophobic magnetic MF@PDA/Fe3O4@SA foam. The foam has excellent capacity, acid resistance, alkali resistance, flame retardant, and salt resistance and can be conveniently separated, recycled, and recovered using magnetism. At the same time, peroxymonosulfate (PMS) can be activated to generate super-active radicals. Within 16 min, the degradation rate of sulfadiazine (SDZ) reached 99.8 %. Trapping experiments and EPR analysis confirmed the critical roles of ·OH, ·SO4− and 1O2 in SDZ removal. The wide pH working range (1.0 ∼ 13.0) and the slight toxicity of photocatalytic intermediates indicate that the as-prepared MF@PDA/Fe3O4@SA/PMS system has good application potential. The foam has potential practical applications in emergency oil spill rescue and oil/organic solvent wastewater treatment. Furthermore, this study provides a promising strategy for designing and fabricating a novel magnetic foam and photoactivated PMS synergistic system to eliminate pharmaceutical antibiotics effectively.

Novel composites of nano-metal–organic frameworks (IRMOF-3) and silver nanoparticles for the ultra-sensitive performance of SERS sensing and optical fiber modes

Rapid chemical detection of drugs of abuse in biological fluids such as blood and saliva is a concern within medicine and law enforcement. As an outcome, a label-free detection platform takes biological fluid samples with concentrations ranging from extremely high to very low. We obtained experimentally the limit of detection (LOD) of glycerol concentration, corresponding to a minimum resolvable refractive index of 3.4 × 10−7 RIU (refractive index unit). We applied the microfluidic device sensors to the quantitating concentration dopamine solutions. The experiment was recorded in real-time as the concentration of analyte injected exposed to the fiber core surface resulted in a sensitive change in optical power transmission. The presented sensors also exhibited reasonably good reproducibility and higher sensitivity, providing the LOD as 1.02 × 10−11 M. A relatively simple scheme procedure is proposed for the simultaneous detection and quantitative assessment of rhodamine B using surface-enhanced Raman spectroscopy with a limit of detection of 10−12 M and a relative standard deviation of 5.78% across a detection concentration range mainly from 10−5 M to 10−12 M. The obtained results demonstrate the potential of nano-metal–organic framework materials as large-area, label-free optical fiber sensors and SERS-based platforms for biomedical sensing and environmental applications.