Molecularly Imprinted Polymers as Synthetic Antibodies for Protein Recognition: The Next Generation

Molecularly imprinted nanoparticles hitchhiking on neutrophils for precise treatment of ischemic stroke

Ischemic stroke (IS), the most prevalent type of stroke worldwide, is associated with a variety of complex processes, including oxidative stress, apoptosis, and ferroptosis. Recent findings indicate that inhibiting iron overload as a key regulatory mechanism of ferroptosis profoundly influences the pathogenesis and treatment of IS. In addition, enhanced blood-brain barrier (BBB) penetration and precise targeting of the ischaemic site contribute to improved therapeutic outcomes in IS. In this study, we developed FeSO4 templated-molecularly imprinted nanoparticles (MINPs) with high-affinity recognition of ferrous ions (Fe2+). MINPs exhibited physicochemical properties that perfectly match the polarity and condensed structure of Fe2+, resulting in the effective and specific clearance of Fe2+ through efficient and selective adsorption both in vivo and in vitro. Moreover, MINPs hitchhiked circulating neutrophils, thereby facilitating their penetration through BBB and enhancing targeted delivery to the ischemic brain. Our results, supported by transcriptomic analysis, further elucidated the molecular mechanisms by which MINPs significantly inhibit ferroptosis while concurrently regulating apoptosis and inflammation, thereby conferring marked neuroprotection against IS.

Chemical Sensors and Biosensors for Point-of-Care Testing of Pets: Opportunities for Individualized Diagnostics of Companion Animals

Point-of-care testing (POCT) is recognized as one of the most disruptive medical technologies for rapid and decentralized diagnostics. Successful commercial examples include portable glucose meters, pregnancy tests, and COVID-19 self-tests. However, compared to advancements in human healthcare, POCT technologies for companion animals (pets) remain significantly underdeveloped. This Review explores the latest advancements in pet POCT and examines the challenges and opportunities in the field for individualized diagnostics of cats and dogs. The most frequent diseases and their respective biomarkers in blood, urine, and saliva are discussed. We examine key strategies for developing the next-generation POCT devices by harnessing the potential of selective (bio)receptors and high-performing transducers such as lateral flow tests and electrochemical (bio)sensors. We also present the most recent research initiatives and the successful commercial pet POCT technologies. We discuss future trends in the field, such the role of biomarker discovery and development of wearable, implantable, and breath sensors. We believe that advancing pet POCT technologies benefits not only animals but also humans and the environment, supporting the One Health approach.

A general method to improve imprinting efficiency in surface protein imprinting by enhanced pre-assembly

Surface protein-imprinted nanoparticles may replace the expensive and unstable antibodies in biomedical applications but still suffers from a low imprinting efficiency. A main reason may be the insufficient pre-assembly between monomers and template protein in surface imprinting using the conventional surface graft polymerization method. Increasing monomer concentrations enhances pre-assembly, but leads to agglomeration of the particles. To solve the dilemma, here an initiating system consisting of surface-immobilized glucose oxidase and horseradish peroxidase, glucose and acetylacetone was used to synthesize the imprinted coatings. No agglomeration occurs even at high monomer concentrations because of the localized polymerization. When surface imprinting of lysozyme over silica nanoparticles, both adsorption capacity and imprinting factor increase with increasing monomer concentration, because of the enhanced pre-assembly. This strategy was further combined with the "shape-memorable imprint cavity" strategy in which the conventional crosslinker is replaced with a peptide crosslinker capable of undergoing pH-induced helix-coil transition. The resulting surface lysozyme-imprinted silica nanoparticles exhibit high adsorption capacity, high imprinting factor, high selectivity, good reusability, easy and complete template removal under mild conditions, and fast rebinding kinetics. Surface imprinting of other proteins with high imprinting efficiency were also successfully carried out, demonstrating the generality of the strategy. STATEMENT OF SIGNIFICANCE: Surface protein-imprinted nanoparticles have emerged as promising artificial antibodies, but still suffering from low imprinting efficiency, primarily due to insufficient pre-assembly between functional monomers and template proteins. Increasing monomer concentrations enhances pre-assembly but causes particle agglomeration. Here the dilemma was solved by using an initiating system consisting of surface-immobilized glucose oxidase/horseradish peroxidase, glucose, and acetylacetone to achieve localized polymerization. Imprinting efficiency was significantly improved because of enhanced pre-assembly. This strategy was further combined with the "shape-memorable imprint cavity" strategy. Lysozyme-imprinted nanoparticles with high capacity (146.4 mg g-1), high imprinting factor (13.94), reusability, and fast rebinding kinetics was synthesized. Surface imprinting of other proteins with high imprinting efficiency were also successfully carried out, demonstrating the generality of the strategy.

Zwitterionic Molecularly Imprinted Hairy Cellulose Nanocrystals Enable Selective Vancomycin Removal

Access to free, off-target, and nontherapeutic doses of antibiotics is a key driving factor in the emergence of antimicrobial resistance (AMR). Intravenously (IV) administered vancomycin (VAN) is among the last-line antibiotics for treating infections caused by multidrug-resistant Gram-positive bacteria. A fraction of the total IV dose unwantedly reaches the gastrointestinal tract, driving AMR. Selective VAN removal from the complex intestinal fluid may reduce the probability of AMR emergence; however, it remains a significant challenge due to the competitive adsorption of other species. Here, we engineer novel VAN-imprinted polymerized zwitterionic hairy cellulose nanocrystals (ViPZ-HCNC) that selectively capture VAN with a removal capacity of ∼ 235 mg g-1 at an imprinting factor of ∼ 7.5. ViPZ-HCNC provide the first nanocellulose-based material with an excellent selectivity for VAN against lysine, lysozyme, and bovine serum albumin, which efficiently remove VAN from calcium ion-containing solutions and simulated intestinal fluids. Additionally, ViPZ-HCNC are not toxic against NIH/3T3 murine fibroblast cells. We envision that ViPZ-HCNC may pave the way for developing soft materials that selectively remove off-target VAN from a broad range of media, preventing VAN resistance evolution. This research is a step forward in addressing the long-lasting AMR challenge using a biobased platform.

Dual-template epitope imprinted nanoparticles for anti-glycolytic tumor-targeted treatment

Glycolysis provides tumors with abundant nutrients through glucose (Glu) metabolism. As a therapeutic target, precise targeting and effective inhibition of the glycolysis process remains a major challenge in anti-metabolic therapy. In this study, a novel dual-template molecularly imprinted polymer (D-MIP), capable of specifically recognizing glucose transporter member 1 (GLUT1) and hexokinase-2 (HK2) was prepared for anti-glycolytic tumor therapy. The imprinting factors of D-MIP for the recognition of the template molecules, the GLUT1 epitope and the HK2 epitope, were 2.1 and 2.5, respectively, enabling specific recognition of the entire target protein. Targeting GLUT1 with D-MIP could impede its Glu uptake, while simultaneously inhibiting the activity of cytoplasmic HK2, thereby reducing the metabolic rate of Glu. Cell experiments demonstrated that inhibition of HK2 resulted in downregulation of the downstream, products glucose-6-phosphate (6PG) and lactate (LA). In vitro and in vivo experimental results indicated that D-MIP exhibited significant targeting and inhibitory effects on GLUT1 and HK2, respectively, which suppressed tumor glycolysis and induced apoptosis in MCF-7 cells. Furthermore, mouse tumor models and hematoxylin-eosin (H&E) staining confirmed the excellent anti-tumor efficacy and favorable biocompatibility of D-MIP. This work represents the first design and development of a dual-template imprinted polymer targeting key transport channels and metabolic enzymes involved in glycolysis, advancing the research and application of anti-glycolytic tumor therapy.

Preparation of Temperature-Sensitive Molecularly Imprinted Cryogel for Specific Recognition of Proteins

In order to maintain the stability of the structure of protein molecules and improve the recognition during the separation process, molecular imprinting technology is combined with freeze polymerization to synthesize molecular imprinting cryogels (MICs). This study uses bovine serum albumin (BSA) as a template protein, low critical cosolubility temperature (LCST)-type ionic liquids as temperature-sensitive functional monomers, imidazole ionic liquids, and acrylamides as auxiliary functional monomers to prepare MICs with specific recognition, temperature sensitivity, interpenetrating macroporous structure, and large specific surface area. The MICs prepared at freezing temperature have uniform macroporous structures and good mechanical properties, which is conducive to the improvement of the mass transfer and adsorption capacities. Due to the advantages, the MIC reaches the adsorption equilibrium within 125 min with a saturated adsorption capacity of 741.5 mg g-1 and an imprinting factor of 1.65. Their static and dynamic adsorption behaviors are more in line with the Langmuir model and the quasi-secondary kinetic model, respectively. In addition, the MIC has obvious temperature sensitivity, and the maximum adsorption amount is reached at 37 °C. The separation factor (relative to cytochrome c, bovine blood hemoglobin, and lysozyme) of the MICs for BSA is up to 1.39. Repeatability experiments reveal that the adsorption capacity of molecularly imprinted cryogels is retained at 87% after five adsorption-desorption cycles, indicating excellent recyclability and potential for practical application.

Design and development of pH-sensitive nanocarriers using molecularly imprinted polymers for the targeted delivery of sodium thiopental

Sodium thiopental (STL) is an ultrashort-acting barbiturate that acts quickly on the brain, reduces levels of adrenaline, noradrenaline, and dopamine, and has neuroprotective properties. However, its side effects, especially in high doses, can be severe, including respiratory failure and cardiac complications. Molecularly imprinted polymers (MIPs) are three-dimensional polymeric networks that mimic the structure and functionality of target molecules. MIPs include benefits such as stability, selectivity, and cost-effectiveness. Combination with magnetic nanoparticles (MNPs) not only enhances their stability and biocompatibility but also provides magnetic separation capabilities. This research introduces the design and synthesis of pH-sensitive MIPs as targeted nanocarriers for the selective uptake and controlled release of STL molecules. The MIPs were synthesized in various forms, including magnetic core MIPs (MMIPs), standard MIPs (MIPs), and fiber-shaped MIPs (MIPF), to explore their comparative efficiency and structural advantages. Bemegride (BMG), an antidote structurally similar to STL, was utilized to evaluate the selectivity of these MIP systems. The formation of specific binding sites of STL on MIPs during the polymerization process leads to selective recognition and matches STL's shape, size, and functional groups. In this regard, all types of MIPs exhibited significant rebinding affinities over their non-imprinted polymer (NIP); specifically, MMIPs displayed a high affinity for uptake of STL (393.8 ± 1.328%) against BMG (360.72 ± 6.72%) over 24 h. The pH sensitivity of the nanocarriers was investigated in simulated gastric fluid (SGF) and simulated intestinal fluids (SIF) environments. The quantitative results indicated that the prepared nanocarriers showed a controlled release in SIF environments. MMIPs achieved a release efficiency for STL and BMG of approximately 57.7 ± 0.6% and 85.4 ± 4.6%, respectively, over a 78-hour period. These findings highlight the potential of MMIPs for dual-uptake and targeted release applications of STL in specific pH environments.

Biomimetic Molecularly Imprinted Nanogels for the Recognition of Spike Glycoproteins

The rapid spread and mutation of SARS-CoV-2, the virus responsible for COVID-19, has set the foundation for extensive research into next-generation therapeutic strategies. A critical component of SARS-CoV-2 is the trimeric Spike (S) glycoprotein, which facilitates viral entry into host cells by interacting with the receptor-binding domain (RBD). To inhibit and block viral entry, we designed and developed molecularly imprinted synthetic nanogel antibodies (MIP-SNAs) that cap the Spike S1 RBD. This aims to provide a versatile, biosecure, and effective therapeutic tool for the prevention and treatment of SARS-CoV-2 infection. Herein, we employed reverse miniemulsion polymerization to synthesize MIP-SNAs using poly(ethylene glycol) diacrylate (PEGDA), a nontoxic, nonimmunogenic and FDA-approved polymer, able to interact noncovalently with the functional groups of template Spike S1 RBD. In addition, the formulation of MIP-SNAs was based on a preliminary investigation of protein conformation by circular dichroism. Characterization of the SNAs was conducted using several techniques to investigate the chemical structure, thermal stability, size, and morphology. Under optimal conditions, the MIP-SNAs exhibited high specificity, with rebinding capacities up to 6-fold higher compared to the control nonimprinted synthetic nanogel antibodies. MIP-SNAs also demonstrated notable selectivity toward the SARS-CoV-2 Spike S1 RBD protein compared to the structural resembling Spike proteins of Bat-CoV, while cytocompatibility assays confirmed the biocompatible character of the SNAs. Given the excellent features of the recently developed MIP-SNAs, we are one step closer to finding efficient but also patient-friendly prevention and treatment solutions for SARS-CoV-2 infection. Beyond immediate applications, this technology offers the potential for broader diagnostic and therapeutic uses against related viral pathogens.

Dual surrogate imprinting: an innovative strategy for the preparation of virus-selective particles

This work involves the preparation of dual surrogate-imprinted polymers (D-MIPs) for the capture of SARS-CoV-2. To achieve this goal, an innovative and novel dual imprinting approach using carboxylated-polystyrene (PS-COOH) nanoparticles with a diameter of 100 nm and a SARS-CoV-2 Spike-derived peptide was carried out at the surface of amine-functionalized silica (PS-NH2) microspheres with a diameter of 500 nm. Firstly, PS-COOH nanoparticles with the same size and spherical shape as the SARS-CoV-2 virus were employed to form hemispherical indentations (HI) at the surface of the PS-NH2 microspheres (obtaining dummy particle-imprinted polymers, HI-MIPs). Next, a specific peptide sequence representing the Spike protein at the surface of the target virus was also used as the second template to generate specific peptide binding sites at the HI. Finally, the PS-COOH and the peptide were removed by several washing steps providing D-MIPs, comprising both dummy particle indentations (HI) and peptide binding sites. The D-MIPs and HI-MIPs were in-depth characterized via scanning electron microscopy (SEM), transmission electron microscope (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy dispersive X-ray analysis (EDAX). 100% rebinding efficiency was achieved for the SARS-CoV-2 peptide with D-MIPs highlighting its specificity vs. non-peptide-imprinted control polymers (HI-MIPs), which only achieved a binding efficiency of <40.5%. D-MIPs also showed higher affinity than HI-MIPs towards real SARS-CoV-2 virus. Furthermore, lower rebinding percentages for both HI-MIPs (8.5%) and D-MIPs (6.9%) were obtained when incubated with an alternative peptide (i.e., characteristic for Zika virus) indicating a successful peptide imprinting process for the target SARS-CoV-2 peptide.

Dummy-template imprinted bovine serum albumin for extraction of zearalenone

The aim of this study is to develop molecularly imprinted protein specific to zearalenone (ZEN). The primary idea of our study was to replace the toxic template-ZEN-with a dummy-template-4-hydroxicoumarin-during the synthesis of imprinted proteins (IPs). The choice of the dummy-template was based on the results of comprehensive evaluation that included a combination of blind docking and molecular dynamics simulations. Furthermore, we studied the influence of protonation and purification conditions to IPs sorption capacity. 3D fluorescence spectroscopy was used to monitor the process of bovine serum albumin (BSA) imprinting. The modified purification approach allowed reducing the eluent volume and purification time by approximately 300 and 48 times, respectively. The imprinted BSA was then used to produce a bioinorganic sorbent (IPs-BIS) based on silica nanoparticles (silica NPs), that, as far as we know, was never described before. The synthesized IPs-BIS were successfully applied as ZEN sorbents in model solutions (Qmax = 1.70 ± 0.15 mg g- 1 , imprinting factor = 2.5) and artificially contaminated wheat extract (Qmax = 2.24 ± 0.02 mg g- 1 ) confirmed by HPLC-UV. We believe that our method can be used for mycotoxin monitoring in animal feeds and foodstuff.

Selective Hydrolysis of Heterooligosaccharides by Poly(acrylate) Gel Catalysts

Natural glycoside hydrolases are distinguished by their ability to hydrolyze glycosidic bonds with high efficiency and selectivity. This feature is achieved through specific interactions in the active site during catalytic turnover and is not just facilitated by two catalytically active amino acids. Intrigued by these features, a biomimetic α-galactosidase mimic was developed using an empirical catalyst design. Starting with a library of 704 gels of which 250 have a unique composition synthesized from TEGDMA cross-linker and 7 selected monomers, 238 monomodal gels are evaluated for their ability to hydrolyze the 1→6 α-glycosidic bond in the disaccharide melibiose. Among those, 13 polyacrylate gels with the potential for high catalytic activity are identified using spectrophotometric screening assays based on Schiff bases formed with toluidine. The best-performing polyacrylate (gel A) was found to have a 1500-fold higher proficiency to hydrolyze the 1→6 α-glycosidic bond in melibiose over the 1→2 α-glycosidic bond in sucrose, translating to selective hydrolysis of the glycosidic linkages in the trisaccharide raffinose. The matrix of gel A is composed of 25 mol % TEGDMA cross-linker and equimolar amounts of cyclohexyl, butyl, and benzyl acrylate accounting for CH-π and hydrophobic interaction in the surrounding of a hydrolytic binuclear Cu(II) complex. The combined observations underline a paramount influence of matrix-stabilizing effects on the transition state of the hydrolysis of glycosidic bonds and may pave the way for the rapid development of catalysts transforming biomass.

Hemicellulose-Based Sensors: When Sustainability Meets Complexity

Hemicelluloses (HCs) are promising sustainable biopolymers with a great natural abundance, excellent biocompatibility, and biodegradability. Yet, their potential sensing applications remain limited due to intrinsic challenges in their heterogeneous chemical composition, structure, and physicochemical properties. Herein, recent advances in the development of HC-based sensors for different chemical analytes and physical stimuli using different transduction mechanisms are reviewed and discussed. HCs can be utilized as carbonaceous precursors, reducing, capping, and stabilizing agents, binders, and active components for sensing applications. In addition, different strategies to develop and improve the sensing capacity of HC-based sensors are also highlighted.

Immunodetection of Poorly Soluble Substances: Limitations and Their Overcoming

Immunoassays based on the specific antigen-antibody interactions are efficient tools to detect various compounds and estimate their content. Usually, these assays are implemented in water-saline media with composition close to physiological conditions. However, many substances are insoluble or cannot be molecularly dispersed in such media, which objectively creates problems when interacting in aquatic environments. Thus, obtaining immunoreactants and implementing immunoassays of these substances need special methodological solutions. Hydrophobicity of antigens as well as their limited ability to functionalization and conjugation are often overlooked when developing immunoassays for these compounds. The main key finding is the possibility to influence the behavior of hydrophobic compounds for immunoassays, which requires specific approaches summarized in the review. Using the examples of two groups of compounds-surfactants (alkyl- and bisphenols) and fullerenes, we systematized the existing knowledge and experience in the development of immunoassays. This review addresses the challenges of immunodetection of poorly soluble substances and proposes solutions such as the use of hydrotropes, other solubilization techniques, and alternative receptors (aptamers and molecularly imprinted polymers).

Chitosan-graphene quantum dot-based molecular imprinted polymer for oxaliplatin release

Molecularly imprinted polymers (MIPs) have garnered the interest of researchers in the drug delivery due to their advantages, such as exceptional durability, stability, and selectivity. In this study, a biocompatible MIP drug adsorption and delivery system with high loading capacity and controlled release, was prepared based on chitosan (CS) and graphene quantum dots (GQDs) as the matrix, and the anticancer drug oxaliplatin (OXAL) as the template. Additionally, samples without the drug (non-imprinted polymers, NIPs) were created for comparison. GQDs were produced using the hydrothermal method, and samples underwent characterization through FTIR, XRD, FESEM, and TGA. Various experiments were conducted to determine the optimal pH for drug adsorption, along with kinetic and isotherm studies, selectivity assessments, in vitro drug release and kinetic evaluations. The highest drug binding capacity was observed at pH 6.5. The results indicated the Lagergren-first-order kinetic model (with rate constant of 0.038 min-1) and the Langmuir isotherm (with maximum adsorption capacity of 17.15 mg g-1) exhibited better alignment with the experimental data. The developed MIPs displayed significant selectivity towards OXAL, by an imprinting factor of 2.88, in comparison to two similar drugs (cisplatin and carboplatin). Furthermore, the analysis of the drug release profile showed a burst release for CS-Drug (87% within 3 h) at pH 7.4, where the release from the CS-GQD-Drug did not occur at pH 7.4 and 10; instead, the release was observed at pH 1.2 in a controlled manner (100% within 28 h). Consequently, this specific OXAL adsorption and delivery system holds promise for cancer treatment.

A second generation of senotherapies: the development of targeted senolytics, senoblockers and senoreversers for healthy ageing

Cellular senescence, a form of terminal cell cycle arrest, is as a key driver of organismal ageing and an important factor in age-related diseases. Insights into the senescent phenotype have led to the development of novel therapeutic strategies, collectively known as senotherapies, that aim to ameliorate the detrimental effects of senescent cell accumulation in tissues. The senotherapeutic field has rapidly evolved over the past decade, with clinical translation of the first drugs discovered currently underway. What began as the straightforward removal of senescent cells using repurposed compounds, which were given the name of senolytics, has grown into an expanding field that uses different state of the art approaches to achieve the goal of preventing the build-up of senescent cells in the body. Here, we summarize the emergence of a new generation of senotherapies, based on improving the efficacy and safety of the original senolytics by making them targeted, but also branching out into drugs that prevent senescence (senoblockers) or revert it (senoreversers).The use of nanotechnology, specific antibodies, cell-based approaches and restored immunosurveillance is likely to revolutionize the field of senotherapies in the near future, hopefully allowing it to realize its full clinical potential.

Effect of Various Carbon Electrodes on MIP-Based Sensing Proteins Using Poly(Scopoletin): A Case Study of Ferritin

Sensitivity in the sub-nanomolar concentration region is required to determine important protein biomarkers, e.g., ferritin. As a prerequisite for high sensitivity, in this paper, the affinity of the functional monomer to the macromolecular target ferritin in solution was compared with the value for the respective molecularly imprinted polymer (MIP)-based electrodes, and the influence of various surface modifications of the electrode was investigated. The analytical performance of ferritin sensing was investigated using three different carbon electrodes (screen-printed carbon electrodes, single-walled-carbon-nanotube-modified screen-printed carbon electrodes, and glassy carbon electrodes) covered with a scopoletin-based MIP layer. Regardless of the electrode type, the template molecule ferritin was mixed with the functional monomer scopoletin, and electropolymerization was conducted using multistep amperometry. All stages of MIP preparation were followed by evaluating the diffusional permeability of the redox marker ferricyanide/ferrocyanide through the polymer layer by differential pulse voltammetry. The best results were obtained with glassy carbon electrodes. The MIP sensor responded up to 0.5 µM linearly with a Kd of 0.30 µM. Similar results were also obtained in solution upon the interaction of scopoletin and ferritin using fluorescence spectroscopy, resulting in the quenching of the scopoletin signal, with a calculated Kd of 0.81 µM. Moreover, the binding of 1 µM ferritin led to 49.6% suppression, whereas human serum albumin caused 8.6% suppression.

Portable, intelligent MIECL sensing platform for ciprofloxacin detection using a fast convolutional neural networks-assisted Tb@Lu2O3 nanoemitter

Environmental pollution caused by ciprofloxacin is a major problem of global public health. A machine learning-assisted portable smartphone-based visualized molecularly imprinted electrochemiluminescence (MIECL) sensor was developed for the highly selective and sensitive detection of ciprofloxacin (CFX) in food. To boost the efficiency of electrochemiluminescence (ECL), oxygen vacancies (OVs) enrichment was introduced into the flower-like Tb@Lu2O3 nanoemitter. With the specific recognition reaction between MIP as capture probes and CFX as detection target, the ECL signal significantly decreased. According to, CFX analysis was determined by traditional ECL analyzer detector in the concentration range from 5 × 10-4 to 5 × 102 μmol L-1 with the detection limit (LOD) of 0.095 nmol L-1 (S/N = 3). Analysis of luminescence images using fast electrochemiluminescence judgment network (FEJ-Net) models, achieving portable and intelligent quick analysis of CFX. The proposed MIECL sensor was used for CFX analysis in real meat samples and satisfactory results, as well as efficient selectivity and good stability.

Wavelength Division Multiplexing-Based High-Sensitivity Surface Plasmon Resonance Imaging Biosensor for High-Throughput Real-Time Molecular Interaction Analysis

In this study, we report the successful development of a novel high-sensitivity intensity-based Surface Plasmon Resonance imaging (SPRi) biosensor and its application for detecting molecular interactions. By optimizing the excitation wavelength and employing a wavelength division multiplexing (WDM) algorithm, the system can determine the optimal excitation wavelength based on the initial refractive index of the sample without adjusting the incidence angle. The experimental results demonstrate that the refractive index resolution of the system reaches 1.77×10-6 RIU. Moreover, it can obtain the optimal excitation wavelength for samples with an initial refractive index in the range of 1.333 to 1.370 RIU and accurately monitor variations within the range of 0.0037 RIU without adjusting the incidence angle. Additionally, our new SPRi technique realized real-time detection of high-throughput biomolecular binding processes, enabling analysis of kinetic parameters. This research is expected to advance the development of more accurate SPRi technologies for molecular interaction analysis.

Carbon-dots encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer: A facile fluorescent probe for the determination of chloramphenicol

In this study, carbon dots (CDs)-encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer (CDs@MOF@SMIP) was facilely prepared and applied as fluorescent probe for specific identification and sensitive detection of chloramphenicol (CAP) in food. Fluorescent CDs, serving as signal tags, were encapsulated within metal-organic backbones (ZIF-8), yielding luminescent MOF materials (CDs@ZIF-8). The synthesized CDs, CDs@ZIF-8 and CDs@ZIF-8@SMIP were investigated by morphological and structural characterizations (UV-Vis, XRD, FT-IR, BET, TEM). The CDs@ZIF-8@SMIP probe was demonstrated to have remarkable selectivity and sensitivity towards CAP. Its fluorescence decreased linearly with CAP concentration from 0.323 μg L-1 (0.001 μM) to 8075.0 μg L-1 (25.0 μM), featuring a low detection limit of 0.08 μg L-1. The CDs@ZIF-8@SMIP-based fluorescence strategy achieved satisfactory recoveries (95.5 % - 101.0 %) in CAP-spiked commercial foods with RSD < 4.4 % (n = 3). These results indicate that this method can effectively detect trace CAP in food matrices and has broad application prospects.

Pathogen-binding nanoparticles to inhibit host cell infection by heparan sulfate and sialic acid dependent viruses and protozoan parasites

Global health faces an immense burden from infectious diseases caused by viruses and intracellular protozoan parasites such as the coronavirus disease (COVID-19) and malaria, respectively. These pathogens propagate through the infection of human host cells. The first stage of this host cell infection mechanism is cell attachment, which typically involves interactions between the infectious agent and surface components on the host cell membranes, specifically heparan sulfate (HS) and/or sialic acid (SA). Hence, nanoparticles (NPs) which contain or mimic HS/SA that can directly bind to the pathogen surface and inhibit cell infection are emerging as potential candidates for an alternative anti-infection therapeutic strategy. These NPs can be prepared from metals, soft matter (lipid, polymer, and dendrimer), DNA, and carbon-based materials among others and can be designed to include aspects of multivalency, broad-spectrum activity, biocidal mechanisms, and multifunctionality. This review provides an overview of such anti-pathogen nanomedicines beyond drug delivery. Nanoscale inhibitors acting against viruses and obligate intracellular protozoan parasites are discussed. In the future, the availability of broadly applicable nanotherapeutics would allow early tackling of existing and upcoming viral diseases. Invasion inhibitory NPs could also provide urgently needed effective treatments for protozoan parasitic infections.

Multifunctional Self-Signaling nanoMIP and Its Application for a Washing-Free Assay of Human Angiotensin-Converting Enzyme 2

Molecular imprinting techniques have attracted a lot of attention as a potential biomimetic technology, but there are still challenges in protein imprinting. Herein, multifunctional nanosized molecularly imprinted polymers (nanoMIPs) for human angiotensin-converting enzyme 2 (ACE2) were prepared by epitope imprinting of magnetic nanoparticles-anchored peptide (magNP-P) templates, which were further applied to construct a competitive displacement fluorescence assay toward ACE2. A cysteine-flanked dodecapeptide sequence was elaborately selected as an epitope for ACE2, which was immobilized onto the surface of magnetic nanoparticles and served as a magNP-P template for imprinting. During polymerization, fluorescent monomers were introduced to endow fluorescence responsiveness to the prepared self-signaling nanoMIPs. A competitive displacement fluorescence assay based on the nanoMIPs was established and operated in a washing-free manner, yielding a wide range for ACE2 (0.1-6.0 pg/mL) and a low detection limit (0.081 pg/mL). This approach offers a promising avenue in the preparation of nanoMIPs for macromolecule recognition and expands potential application of an MIP in the detection of proteins as well as peptides.

Cell-penetrating protein-recognizing polymeric nanoparticles through dynamic covalent chemistry and double imprinting

Molecular recognition of proteins is key to their biological functions and processes such as protein-protein interactions (PPIs). The large binding interface involved and an often relatively flat binding surface make the development of selective protein-binding materials extremely challenging. A general method is reported in this work to construct protein-binding polymeric nanoparticles from cross-linked surfactant micelles. Preparation involves first dynamic covalent chemistry that encodes signature surface lysines on a protein template. A double molecular imprinting procedure fixes the binding groups on the nanoparticle for these lysine groups, meanwhile creating a binding interface complementary to the protein in size, shape, and distribution of acidic groups on the surface. These water-soluble nanoparticles possess excellent specificities for target proteins and sufficient affinities to inhibit natural PPIs such as those between cytochrome c (Cytc) and cytochrome c oxidase (CcO). With the ability to enter cells through a combination of energy-dependent and -independent pathways, they intervene apoptosis by inhibiting the PPI between Cytc and the apoptotic protease activating factor-1 (APAF1). Generality of the preparation and the excellent molecular recognition of the materials have the potential to make them powerful tools to probe protein functions in vitro and in cellulo.

Immune-like sandwich multiple hotspots SERS biosensor for ultrasensitive detection of NDKA biomarker in serum

Developing the rapid, specific, and sensitive tumor marker NDKA biosensor has become an urgent need in the field of early diagnosis of colorectal cancer (CRC). Surface-enhanced Raman spectroscopy (SERS) with the advantages of high sensitivity, high resolution as well as providing sample fingerprint, enables rapid and sensitive detection of tumor markers. However, many SERS biosensors rely on boosting the quantity of Raman reporter molecules on individual nanoparticle surfaces, which can result in nanoparticle agglomeration, diminishing the stability and sensitivity of NDKA detection. Here, we proposed an immune-like sandwich multiple hotspots SERS biosensor for highly sensitive and stable analysis of NDKA in serum based on molecularly imprinted polymers and NDKA antibody. The SERS biosensor employs an array of gold nanoparticles, which are coated with a biocompatible polydopamine molecularly imprinted polymer as a substrate to specifically capture NDKA. Then the biosensor detects NDKA through Raman signals as a result of the specific binding of NDKA to the SERS nanotag affixed to the capture substrate along with the formation of multiple hotspots. This SERS biosensor not only avoids the aggregation of nanoparticles but also presents a solution to the obstacles encountered in immune strategies for certain proteins lacking multiple antibody or aptamer binding sites. Furthermore, the practical application of the SERS biosensor is validated by the detection of NDKA in serum with the lower limit of detection (LOD) of 0.25 pg/mL, meanwhile can detect NDKA of 10 ng/mL in mixed proteins solution, illustrating high sensitivity and specificity. This immune-like sandwich multiple hotspots biosensor makes it quite useful for the early detection of CRC and also provides new ideas for cancer biomarker sensing strategy in the future.

Molecular Imprinting-Based SERS Detection Strategy for the Large-Size Protein Quantitation and Curbing Non-Specific Recognition

Molecular imprinting-based surface-enhanced Raman scattering (MI-SERS) sensors have shown remarkable potential from an academic standpoint. However, their practical applications, especially in the detection of large-size protein (≥10 nm), face challenges due to the lack of versatile sensing strategies and nonspecific fouling of matrix species. Herein, we propose a Raman reporter inspector mechanism (RRIM) implemented on a protein-imprinted polydopamine (PDA) layer coated on the SERS active substrate. In the RRIM, after large-size protein recognition, the permeability of the PDA imprinted cavities undergoes changes that are scrutinized by Raman reporter molecules. Target proteins can specifically bind and fully occupy the imprinted cavities, whereas matrix species cannot. Then, Raman reporter molecules with suitable size are introduced to serve as both inspectors of the recognition status and inducers of the SERS signal, which can only penetrate through the vacant and nonspecifically filled cavities. Consequently, changes in the SERS signal exclusively originate from the specific binding of target proteins, while the nonspecific recognition of matrix species is curbed. The RRIM enables reproducible quantitation of the large-size cyanobacteria-specific protein model (≥10 nm), phycocyanin, at the level down to 2.6 × 10-3 μg L-1. Finally, the practical applicability of the RRIM is confirmed by accurately analyzing crude urban waterway samples over 21 min without any pretreatment.

Alumina inorganic molecularly imprinted polymer modified multi-walled carbon nanotubes for uric acid detection in sweat

Alumina inorganic molecularly imprinted polymer (MIP) modified multi-walled carbon nanotubes (MWCNTs) on a glassy carbon electrode (MWCNTs-Al2O3-MIP/GCE) was firstly designed and fabricated by one-step electro deposition technique for the detection of uric acid (UA) in sweat. The UA templates were embedded within the inorganic MIP by co-deposition with Al2O3. Through the evaluation of morphology and structure by Field Emission Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM), it was verified that the specific recognition sites can be fabricated in the electrodeposited Al2O3 molecular imprinted layer. Due to the high selectivity of molecular imprinting holes, the MWCNTs-Al2O3-MIP/GCE electrode demonstrated an impressive imprinting factor of approximately 2.338 compared to the non-molecularly imprinted glassy carbon electrode (MWCNTs-Al2O3-NIP/GCE) toward uric acid detection. Moreover, it exhibited a remarkable limit of detection (LOD) of 50 nM for UA with wide detection range from 50 nM to 600 μM. The MWCNTs-Al2O3-MIP/GCE electrode also showed strong interference resistance against common substances found in sweat. These results highlight the excellent interference resistance and selectivity of MWCNTs-Al2O3-MIP/GCE sensor, positioning it as a novel sensing platform for non-invasive uric acid detection in human sweat.

Integrating molecular imprinting into flexible covalent organic frameworks for selective recognition and efficient extraction of aflatoxins

Covalent organic frameworks (COFs) are promising adsorbents for extraction, but their selectivity for molecular recognition remains a challenging issue due to the very limited structural design with rigid structure. Herein, we report an elegant strategy for the design and synthesis of molecularly imprinted flexible COFs (MI-FCOFs) via one-pot reaction between the flexible building block of 2,4,6-tris(4-formylphenoxy)- 1,3,5-triazine and linear 4-phenylenediamine for selective extraction of aflatoxins. The flexible chain structure enabled the developed MI-FCOF to adjust the shape and conformation of frameworks to suit the template molecule, giving high selectivity for aflatoxins recognition. Moreover, MI-FCOF with abundant imprinted sites and function groups exhibited an exceptional adsorption capacity of 258.4 mg g-1 for dummy template which is 3 times that of no-imprinted FCOF (NI-FCOF). Coupling MI-FCOF based solid-phase extraction with high-performance liquid chromatography gave low detection limits of 0.003-0.09 ng mL-1 and good precision with relative standard deviations ≤ 6.7% for the determination of aflatoxins. Recoveries for the spiked rice, corn, wheat and peanut samples were in the range of 85.4%- 105.4%. The high selectivity of the developed MI-FCOF allows matrix-free determination of AFTs in food samples. This work offers a new way to the design of MI-FCOF for selective molecular recognition.

Fabrication of double imprinted anchor points in cellulose nanocrystals-based hierarchical porous polyHIPEs for selective separation of flavoniods under physiological pH

Previous research had proved that molecular imprinted polymers can be used as separation material for removing Naringin (NRG) from agricultural pomelo wastes effectively. But the adsorption amounts of NRG molecules from traditional MIPs was quite low by using boronic acid as functional monomer because of single affinity interaction. Therefore, we developed the new combination of bifunctional monomers (i.e. low pKa boronate affinity monomer 2,4-difluoro-3-formylphenylboronic acid and dopamine) based on cellulose nanocrystals (CNCs) mixed with polymerized high internal phase emulsion (polyHIPE, PH) through an double layer surface imprinted method. The introduction of polyethylenimine (PEI) can offer abundant anchor units for the growth of more anchor sites to immobilization template molecules. Importantly, largely improved selective adsorption amounts (50.79 μmol g-1), which may be attribute to the fabrication of the uniform growth of double imprinted layers onto the polydopamine (PDA)/boronic acid-based surfaces. In addition, the resulting double recognition molecular imprinted polymers (MIPs) based on hypercrosslinked PH (DR-HCLPH@MIPs) not only exhibited fast adsorption kinetic of NRG molecule, but also possessed excellent selectivity and high adsorption capacities at physiological pH. Meanwhile, the coarse NRG from pomelo waste can be high selectively extracted to 94.74%. Overall, this study provides a versatile approach for fabrication of the sandwich-biscuit-like double imprinting layer porous MIPs for precise identification and ultrafast transport separation of NRG from complex samples.

Tailoring molecular recognition in predesigned multifunctional enzyme mimicking porphyrin imprinted interface for high affinity and differential selectivity; sensing etoposide in lung cancer patients

Nanozymes are cost-effective and robust but they lack specificity and selectivity, limiting their potential practical applications. Herein, molecularly imprinted polymers (MIPs) were grown in combination with multifunctional 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin (THPP) oxidase-like nanozyme to engineer THPP@MIP interface with high affinities and differential selectivity for structurally related target analytes. THPP nanozyme displayed a high level of predefined binding affinity for etoposide (ETO), and served as a predesigned functional monomer to rationally tailor the selectivity of THPP@MIP surface in the presence of different guest molecules. THPP nanozyme in combination with conventional monomers was imprinted on a portable and disposable cellulose paper matrix under UV light to create a UV-cured imprinted interface for optical detection of ETO. The THPP@MIP enzyme mimicking interface, having ETO specific and selective target recognition pockets, catalyzed the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to generate visible blue oxidized TMB (oxTMB) without exogenous hydrogen peroxide (H2O2). The ETO binding on the THPP@MIP surface blocked the channels for TMB access to THPP cavities. The THPP@MIP sensor permitted to detect ETO in the linear range of 0.005-10 μg mL-1, with a limit of detection (LoD) of 0.002 μg mL-1, and showed a remarkable specificity and selectivity against other drug molecules. Furthermore, the THPP@MIP sensor successfully differentiated the serum samples of lung cancer patients and healthy volunteers. The obtained results were validated with standard High performance liquid chromatography-mass spectrometry (HPLC/MS) analysis of the serum samples. Additionally, ETO injection/infusion solutions and ETO-free serum samples were used to perform the matrix effect and recovery studies. This work demonstrates that molecular imprinting with predesigned, enzyme mimicking, high-affinity functional monomer can serve as a highly selective and specific universal interface for broad spectrum sensing applications in various analytical domains.

Hybrid Impedimetric Biosensors for Express Protein Markers Detection

Impedimetric biosensors represent a powerful and promising tool for studying and monitoring biological processes associated with proteins and can contribute to the development of new approaches in the diagnosis and treatment of diseases. The basic principles, analytical methods, and applications of hybrid impedimetric biosensors for express protein detection in biological fluids are described. The advantages of this type of biosensors, such as simplicity and speed of operation, sensitivity and selectivity of analysis, cost-effectiveness, and an ability to be integrated into hybrid microfluidic systems, are demonstrated. Current challenges and development prospects in this area are analyzed. They include (a) the selection of materials for electrodes and formation of nanostructures on their surface; (b) the development of efficient methods for biorecognition elements' deposition on the electrodes' surface, providing the specificity and sensitivity of biosensing; (c) the reducing of nonspecific binding and interference, which could affect specificity; (d) adapting biosensors to real samples and conditions of operation; (e) expanding the range of detected proteins; and, finally, (f) the development of biosensor integration into large microanalytical system technologies. This review could be useful for researchers working in the field of impedimetric biosensors for protein detection, as well as for those interested in the application of this type of biosensor in biomedical diagnostics.

In2O3/Bi2S3 S-scheme Heterojunction-Driven Molecularly Imprinted Photoelectrochemical Sensor for Ultrasensitive Detection of Florfenicol

Florfenicol (FF) raises significant human health and environmental concerns due to its toxicity to the hematology system and the potential spread of antibiotic-resistant genes. Here, a highly sensitive molecularly imprinted photoelectrochemical (PEC) sensor, featuring an In2O3/Bi2S3 S-scheme heterojunction, is proposed to detect FF without an external voltage supply. Compared with conventional II-type heterojunctions, S-scheme heterojunctions efficiently promote carrier separation and enhance the redox capability of the photocatalytic system. This allows more dissolved O2 and H2O molecules to participate in the redox reaction, resulting in an amplified and stabilized photocurrent response. The electron transfer in the S-scheme heterojunction is confirmed via electron spin resonance (ESR). With the molecular imprinting technique, this PEC platform exhibits exceptional selectivity, wide linear range (1.0 × 10-4-1.0 × 104 ng mL-1), low detection limit (6.4 × 10-5 ng mL-1), and applicability in real milk and chicken samples. This work not only showcases a PEC platform for accurately and portably detecting drugs but also proposes a viable approach for designing S-scheme heterojunctions in sensing analysis.

Protein-imprinted polymers: How far have "plastic antibodies" come?

Antibodies are highly selective and sensitive, making them the gold standard for recognition affinity tools. However, their production cost is high and their downstream processing is time-consuming. Molecularly imprinted polymers (MIPs) are tailor-made by incorporating specific molecular recognition sites in their structure, thus translating into receptor-like activity mode of action. The interest in molecular imprinting technology, applied to biomacromolecules, has increased in the past decade. MIPs, produced using biomolecules as templates, commonly referred to as "plastic antibodies" or "artificial receptors", have been considered as suitable cheaper and easy to produce alternatives to antibodies. Research on MIPs, designed to recognize proteins or peptides is particularly important, with potential contributions towards biomedical applications, namely biosensors and targeted drug delivery systems. This mini review will cover recent advances on (bio)molecular imprinting technology, where proteins or peptides are targeted or mimicked for sensing and therapeutic applications. Polymerization methods are reviewed elsewhere, being out of the scope of this review. Template selection and immobilization approaches, monomers and applications will be discussed, highlighting possible drawbacks and gaps in research.

Sequentially Controlled Recognition of Different Proteins Using Programmable Protein Imprinted Nanospheres

Although protein imprinted materials with multiple templates are developed to selectively separate different proteins, it is difficult to achieve the programmed adsorption and separation of different proteins using one material, because the available protein imprinted materials are constructed through irreversible crosslinking and their structures are unprogrammable and non-reconstructive. Herein, a novel nanosphere (MS@PTL-g-PNIPAM) is designed, which not only is temperature and pH responsive but also can dynamically reversibly crosslink/de-crosslink under ultraviolet light of different wavelengths. With the help of the dynamically reversible photo-crosslinking, the nanospheres can be repeatedly programmed into protein imprinted nanospheres toward different target proteins. Moreover, the prepared imprinted nanospheres can easily achieve the controlled rebinding and release of target proteins, benefiting from the introduced temperature- and pH-responsive moieties. As a consequence, this study realizes the specific separation of different target proteins from protein mixture and the real bovine blood sequentially by programming one material. It is resource saving, time saving, recyclable, and it will provide convenience for protein imprinted materials to use in the blood purification, drug delivery, and virus detection.

A rapid abiotic/biotic hybrid sandwich detection for trace pork adulteration in halal meat extract

In this study, we prepared molecularly imprinted polymer nanogels with good affinity for the Fc domain of immunoglobulin G (IgG) using 4-(2-methacrylamidoethylaminomethyl) phenylboronic acid as a modifiable functional monomer for post-imprinting in-cavity modification of a fluorescent dye (F-Fc-MIP-NGs). A novel nanogel-based biotic/abiotic hybrid sandwich detection system for porcine serum albumin (PSA) was developed using F-Fc-MIP-NGs as an alternative to a secondary antibody for fluorescence detection and another molecularly imprinted polymer nanogel capable of recognizing PSA (PSA-MIP-NGs) as a capturing artificial antibody, along with a natural antibody toward PSA (Anti-PSA) that was used as a primary antibody. After incubation of PSA and Anti-PSA with F-Fc-MIP-NGs, the PSA/Anti-PSA/F-Fc-MIP-NGs complex was captured by immobilized PSA-MIP-NGs for fluorescence measurements. The analysis time was less than 30 min for detecting pork adulteration of 0.01 wt% in halal beef and lamb meats. The detection limit was comparable to that of frequently used immunoassays. Therefore, we believe that this method is a promising, sensitive, and rapid detection method for impurities in real samples and could be a simple, inexpensive, and rapid alternative to conventional methods that have cumbersome procedures of 4 hours or more.

Selective Detection of Erythrocytes with QCMs-ABO Blood Group Typing

Blood transfusion, as well as organ transplantation, is only possible after prior blood group (BG) typing and crossmatching. The most important blood group system is that of Landsteiner's ABO classification based on antigen presence on the erythrocyte surfaces. A mass sensitive QCM (quartz crystal microbalance) sensor for BG typing has been developed by utilizing molecular imprinting technology. Polyvinylpyrrolidone (crosslinked with N,N-methylenebisacrylamide) is a favorable coating that was imprinted with erythrocytes of different blood groups. In total, 10 MHz quartz sheets with two resonators, one for MIP (molecularly imprinted polymer) and the other for NIP (non-imprinted polymer) were fabricated and later used for mass-sensitive measurements. The structure of erythrocyte imprints resembles a donut, as identified by AFM (atomic force microscope). All the erythrocytes of the ABO system were chosen as templates and the responses to these selective coatings were evaluated against all blood groups. Each blood group can be characterized by the pattern of responses in an unambiguous way. The results for blood group O are remarkable given that all types of erythrocytes give nearly the same result. This can be easily understood as blood group O does not possess neither antigen A nor antigen B. The responses can be roughly related to the number of respective antigens on the erythrocyte surface. The imprints generate hollows, which are used for reversible recognition of the erythrocytes. This procedure is based on molecular recognition (based on supramolecular strategies), which results from size, shape and enthalpic interactions between host and guest molecules.

Transitioning from Supramolecular Chemistry to Molecularly Imprinted Polymers in Chemical Sensing

This perspective article focuses on the overwhelming significance of molecular recognition in biological processes and its emulation in synthetic molecules and polymers for chemical sensing. The historical journey, from early investigations into enzyme catalysis and antibody-antigen interactions to Nobel Prize-winning breakthroughs in supramolecular chemistry, emphasizes the development of tailored molecular recognition materials. The discovery of supramolecular chemistry and molecular imprinting, as a versatile method for mimicking biological recognition, is discussed. The ability of supramolecular structures to develop selective host-guest interactions and the flexible design of molecularly imprinted polymers (MIPs) are highlighted, discussing their applications in chemical sensing. MIPs, mimicking the selectivity of natural receptors, offer advantages like rapid synthesis and cost-effectiveness. Finally, addressing major challenges in the field, this article summarizes the advancement of molecular recognition-based systems for chemical sensing and their transformative potential.

Synthetic Peptide Antibodies as TNF-α Inhibitors: Molecularly Imprinted Polymer Nanogels Neutralize the Inflammatory Activity of TNF-α in THP-1 Derived Macrophages

Tumor Necrosis Factor-α (TNF-α) is a cytokine that is normally produced by immune cells when fighting an infection. But, when too much TNF-α is produced as in autoimmune diseases, this leads to unwanted and persistent inflammation. Anti-TNF-α monoclonal antibodies have revolutionized the therapy of these disorders by blocking TNF-α and preventing its binding to TNF-α receptors, thus suppressing the inflammation. Herein, we propose an alternative in the form of molecularly imprinted polymer nanogels (MIP-NGs). MIP-NGs are synthetic antibodies obtained by nanomoulding the 3-dimensional shape and chemical functionalities of a desired target in a synthetic polymer. Using an in-house developed in silico rational approach, epitope peptides of TNF-α were generated and 'synthetic peptide antibodies' were prepared. The resultant MIP-NGs bind the template peptide and recombinant TNF-α with high affinity and selectivity, and can block the binding of TNF-α to its receptor. Consequently they were applied to neutralize pro-inflammatory TNF-α in the supernatant of human THP-1 macrophages, leading to a downregulation of the secretion of pro-inflammatory cytokines. Our results suggest that MIP-NGs, which are thermally and biochemically more stable and easier to manufacture than antibodies, and cost-effective, are very promising as next generation TNF-α inhibitors for the treatment of inflammatory diseases.

Mapping and quantifying neuropeptides in the enteric nervous system

Neuropeptides are a highly diverse group of signaling molecules found in the central nervous system (CNS) and peripheral organs, including the enteric nervous system (ENS). Increasing efforts have been focused on dissecting the role of neuropeptides in both neural- and non-neural-related diseases, as well as their potential therapeutic value. In parallel, accurate knowledge on their source of production and pleiotropic functions is still needed to fully understand their implications in biological processes. This review will focus on the analytical challenges involved in studying neuropeptides, particularly in the ENS, a tissue where their abundance is low, together with opportunities for further technical development.

Colloidal antibiotic mimics: selective capture and killing of microorganisms by shape-anisotropic colloids

The development of targeted and efficient antimicrobials for the selective killing of pathogenic bacteria is of great importance, yet remains challenging. Here, we propose a targeted approach to selectively capture and kill microorganisms with colloidal antibiotic mimics that are readily prepared by common chemical syntheses. The mimics are shape-anisotropic colloids, which can selectively capture shape-matching microorganisms due to lock-key depletion attractions. Furthermore, after being modified with gold nanoparticles (AuNPs) and irradiated with near-infrared light, the colloidal mimics can kill the selectively captured microorganisms due to the localized photothermal effect of the AuNPs. The work demonstrates the important ability of anisotropic colloids to selectively capture and precisely kill microorganisms, which holds considerable promise for safe and adaptive antibacterial therapies without the risk of antibiotic resistance.