Morphological, thermal and drug release studies of poly (methacrylic acid)-based molecularly imprinted polymer nanoparticles immobilized in electrospun poly (ε-caprolactone) nanofibers as dexamethasone delivery system

Utilizing electrospun molecularly imprinted membranes for food industry: Opportunities and challenges

Molecularly imprinted polymers (MIPs) have been widely studied in environmental protection and food industry, owing to their excellent specific recognition and structural stability. However, MIPs prepared by conventional methods suffer from low adsorption capacity and slow mass transfer rate. To date, the combination of electrostatic spinning technology and molecular imprinting technology has been proposed to prepare molecularly imprinted membranes (MIMs) with specific recognition capability, and has shown great attraction in the separation and detection of food additives, as well as the extraction and release of active ingredients. In recent years, MIPs and electrostatic spinning technologies have been investigated and evaluated. However, there is no review of electrostatically spun MIMs for food field. In this review, we focus on the fabrication methods and applications of electrostatically spun MIMs in the food, discuss the challenges in practical food applications, and emphasize the promising applications of electrostatically spun MIMs in food field.

Nanofibrous Conductive Sensor for Limonene: One-Step Synthesis via Electrospinning and Molecular Imprinting

Detecting volatile organic compounds (VOCs) emitted from different plant species and their organs can provide valuable information about plant health and environmental factors that affect them. For example, limonene emission can be a biomarker to monitor plant health and detect stress. Traditional methods for VOC detection encounter challenges, prompting the proposal of novel approaches. In this study, we proposed integrating electrospinning, molecular imprinting, and conductive nanofibers to fabricate limonene sensors. In detail, polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) served here as fiber and cavity formers, respectively, with multiwalled carbon nanotubes (MWCNT) enhancing conductivity. We developed one-step monolithic molecularly imprinted fibers, where S(-)-limonene was the target molecule, using an electrospinning technique. The functional cavities were fixed using the UV curing method, followed by a target molecule washing. This procedure enabled the creation of recognition sites for limonene within the nanofiber matrix, enhancing sensor performance and streamlining manufacturing. Humidity was crucial for sensor working, with optimal conditions at about 50% RH. The sensors rapidly responded to S(-)-limonene, reaching a plateau within 200 s. Enhancing fiber density improved sensor performance, resulting in a lower limit of detection (LOD) of 137 ppb. However, excessive fiber density decreased accessibility to active sites, thus reducing sensitivity. Remarkably, the thinnest mat on the fibrous sensors created provided the highest selectivity to limonene (Selectivity Index: 72%) compared with other VOCs, such as EtOH (used as a solvent in nanofiber development), aromatic compounds (toluene), and two other monoterpenes (α-pinene and linalool) with similar structures. These findings underscored the potential of the proposed integrated approach for selective VOC detection in applications such as precision agriculture and environmental monitoring.

Conductive conduit based on electrospun poly (l-lactide-co-D, l-lactide) nanofibers containing 4-aminopyridine-loaded molecularly imprinted poly (methacrylic acid) nanoparticles used for peripheral nerve regeneration

Using biocompatible polymer nanofibrous conduits with a controlled drug delivery have attracted much attention for peripheral nerve regeneration. This work was aimed at preparing electrospun poly (l-lactide-co-D, l-lactide) (PLDLLA) containing multi-walled carbon nanotubes (MWCNTs) and 4-aminopyridine (4-AP)-loaded molecularly imprinted nanoparticles (MIP_4-AP) as well as evaluating their performance in in vitro and in vivo assessments. After synthesis of MIP_4-AP based on poly (methacrylic acid) with imprinting factor of 1.78, it was incorporated into the PLDLLA/MWCNTs nanofibers to optimize. By adjusting the process variables, the average diameter and electrical conductivity of the nanofibrous sample were 92 nm and 2870 × 10^-7 S cm^-1, respectively. Afterward, 4-AP release of the optimum sample showed the presence of MIP_4-AP leading to initial burst release decrease and plateau level postpone up to 96 h. Moreover, the culture results of PC12 as neuroblastoma cell line on optimal PLDLLA/MWCNTs/MIP_4-AP nanofibrous sample revealed the highest cell proliferation without cytotoxicity compared to neat nanofibers. Eventually, the animal model experiment exhibited that the conductive conduit based on the optimum sample was able to repair the rat's sciatic nerve after four weeks in accordance with sciatic function index and histological studies.

Selective Recognition of Herbicides in Water Using a Fluorescent Molecularly Imprinted Polymer Sensor

Fluorescent molecularly imprinted polymer (FMIP) optosensor was utilized for the selective identification of 2,4-dichlorophenoxacetic acid (2,4-D) due to worldwide pollution caused by using herbicides in agricultural industry. In this regards, two derivatives of polymerizable 1,8-naphthalimide namely, 1,8-naphthalimide containing thiourea (NI) and diethyl amine tagged 1,8-naphthalimide (NII) were used as the receptors and 2,4-D was applied as a template. Also, precipitation polymerization was applied to prepare the fluorescent molecularly imprinted polymer (FMIP). The morphological, structural and thermal analysis was carried out using SEM, TEM, EDS, BET, FTIR, DSC and TGA for characterizing the fluorescent optosensor. The adsorption efficiency of FMIP and FNIP was studied using Langmuir, Freundlich, BET and Redlich Peterson isotherms. The results represented that the adsorption of 2,4-D on FMIP and FNIP agreed the Freundlich adsorption isotherm with correlation coefficient of 0.9935 and 0.9801, respectively. The prepared sensor was able for the selective determination of 2,4-D salt in the linear range of 5 × 10^-7-1 × 10^-3 M with a limit of detection of 16.8 nM. The present study revealed that the FMIP prepared by 1,8-naphthalimide derivative (NI) could potentially recognize the trace concentration of 2,4-D. Graphical Abstract Graphical abstract of flourescene switching mechanism in a fluorescent molecularly imprinted polymer sensor.

Lanthanide-Doped Upconversion Nanocarriers for Drug and Gene Delivery

Compared to traditional cancer treatments, drug/gene delivery is an advanced, safe, and efficient method. Nanoparticles are widely used as nanocarriers in a drug/gene delivery system due to their long circulation time and low multi-drug resistance. In particular, lanthanide-doped upconversion nanoparticles (UCNPs) that can emit UV and visible light by near-infrared (NIR) upconversion demonstrated more efficient and safer drug/gene delivery. Because of the low penetration depth of UV and visible light, a photoinduced reaction such as photocleavage or photoisomerization has proven restrictive. However, NIR light has high tissue penetration depth and stimulates the photoinduced reaction through UV and visible emissions from lanthanide-doped UCNPs. This review discusses the optical properties of UCNPs that are useful in bioapplications and drug/gene delivery systems using the UCNPs as a photoreaction inducer.

Molecularly Imprinted Polymer as an Antibody Substitution in Pseudo-immunoassays for Chemical Contaminants in Food and Environmental Samples

The chemical contaminants in food and the environment are quite harmful to food safety and human health. Rapid, accurate, and cheap detection can effectively control the potential risks derived from these chemical contaminants. Among all detection methods, the immunoassay based on the specific interaction of antibody-analyte is one of the most widely used techniques in the field. However, biological antibodies employed in the immunoassay usually cannot tolerate extreme conditions, resulting in an unstable state in both physical and chemical profiles. Molecularly imprinted polymers (MIPs) are a class of polymers with specific molecular recognition abilities, which are highly robust, showing excellent operational stability under a wide variety of conditions. Recently, MIPs have been used in biomimetic immunoassays for chemical contaminants as an antibody substitute in food and the environment. Here, we reviewed these applications of MIPs incorporated in different analytical platforms, such as enzyme-linked immunosorbent assay, fluorescent immunoassay, chemiluminescent immunoassay, electrochemical immunoassay, microfluidic paper-based immunoassay, and homogeneous immunoassay, and discussed current challenges and future trends in the use of MIPs in biomimetic immunoassays.