Enhancing adsorption capacity while maintaining specific recognition performance of mesoporous silica: a novel imprinting strategy with amphiphilic ionic liquid as surfactant

Enhancing Cytochrome C Recognition and Adsorption through Epitope-Imprinted Mesoporous Silica with a Tailored Pore Size

We have reported the synthesis of epitope-imprinted mesoporous silica (EIMS) with an average pore size of 6.2 nm, which is similar to the geometrical size of the target protein, cytochrome C (Cyt c, 2.6 × 3.2 × 3.3 nm3), showing great recognition and large-scale adsorption performance. The characteristic fragment of Cyt c was used as a template and docked onto the surface of C16MIMCl micelles via multiple interactions. Nitrogen adsorption-desorption and transmission electron microscopy confirmed the successful preparation of EIMS. Due to the ordered pore structure, larger pore size, and high specific surface area, the prepared EIMS show superior specificity (IF = 3.8), excellent selectivity toward Cyt c, high adsorption capacity (249.6 mg g-1), and fast adsorption equilibrium (10 min). This study demonstrates the potential application of EIMS with a controllable pore size for high-effective and large-scale separation of Cyt c, providing a new approach for effective biomacromolecular recognition.

Synthesis and Properties of Cefixime Core-Shell Magnetic Nano-Molecularly Imprinted Materials

Novel core-shell magnetic molecularly imprinted polymers (MMIPs) were synthesized using the sol-gel method for the adsorption of cefixime (CFX). Fe3O4@SiO2 is the core, and molecularly imprinted polymers (MIPs) are the shell, which can selectively interact with CFX. The preparation conditions, adsorption kinetics, adsorption isotherms, selective adsorption ability, and reutilization performance of the MMIPs were investigated. The adsorption capacity of MMIPs for CFX was 111.38 mg/g, which was about 3.5 times that of MNIPs. The adsorption equilibrium time was 180 min. The dynamic adsorption experiments showed that the adsorption process of MMIPs to CFX conformed to the pseudo-second-order model. Through static adsorption study, the Scatchard analysis showed that MMIPs had two types of binding sites-the high-affinity binding sites and the low-affinity binding sites-while the Langmuir model fit the adsorption isotherms well (R2 = 0.9962). Cefepime and ceftiofur were selected as the structural analogs of CFX for selective adsorption studies; the adsorption of CFX by MMIPs was higher than that of other structural analogs; and the imprinting factors of CFX, cefepime, and ceftiofur were 3.5, 1.7, and 1.4, respectively. Furthermore, the MMIPs also showed excellent reusable performance.

Biomedical applications of aptamer-modified chitosan nanomaterials: An updated review

Among polysaccharides of environmental and economic interest, chitosan (CS) is receiving much attention, particularly in the food and biotechnology industries to encapsulate active food ingredients and immobilize enzymes. CS nanoparticles (CS NPs) combine the intrinsic beneficial properties of both natural polymers and nanoscale particles such as quantum size effect, biocompatibility, biodegradability, and ease of modification, and have great potential for bioimaging, drug delivery, and biosensing applications. Aptamers are single-stranded oligonucleotides that can fold into predetermined structures and bind to the corresponding biomolecules. They are mainly used as targeting ligands in biosensors, disease diagnostic kits and treatment strategies. They can deliver contrast agents and drugs into cancer cells and tissues, control microorganism growth and precisely target pathogens. Aptamer-conjugated CS NPs can significantly improve the efficacy of conventional therapies, minimize their side effects on normal tissues, and overcome the enhanced permeability retention (EPR) effect. Further, aptamer-conjugated carbohydrate-based nanobiopolymers have shown excellent antibacterial and antiviral properties and can be used to develop novel biosensors for the efficient detection of antibiotics, toxins, and other biomolecules. This updated review aims to provide a comprehensive overview of the bioapplications of aptamer-conjugated CS NPs used as innovative diagnostic and therapeutic platforms, their limitations, and potential future directions.

Equilibrium, kinetics, and thermodynamics study on the biosorption of reactive levofloxacin antibiotic on Pithophora macroalgae in aqueous solution

Since untreated wastewater from hospitals and residential areas is being discharged directly into surface waterways, pharmaceutical contaminants have been shown to be higher in many countries. Therefore, the development of novel and effective techniques to extract antibiotic substances from wastewater is of utmost importance. The present work aims at the use of green Pithophora macroalgae to remove levofloxacin antibiotic from an aqueous solution through biosorption. Biosorption is an economical and eco-friendly method for treating wastewater. The macroalgae were dried, grounded, and used as biosorbent to remove the levofloxacin (LVX) antibiotics from the aqueous solution. The influence of operating conditions such as initial antibiotic concentration, biosorbent dosage, agitation speed, pH, and temperature was studied. The biosorbent was characterized by FTIR, SEM, and point zero charge. The experimental data were evaluated using Langmuir and Freundlich isotherms. The experimental data best fit the Freundlich isotherm model (R² = 0.969), while the kinetic model for the experiment follows the pseudo-second-order (R² = 0.998) with a maximum biosorption capacity of 17.8 mg/g. Maximized removal of LVX occurs at favorable conditions of 298 K temperature, 150 mg/L initial concentration of antibiotic, 0.5 g sorbent dose, and 6.5 pH. The calculated thermodynamic parameters reveal that the biosorption of LVX antibiotics occurs by an endothermic process. This study deduces that Pithophora macroalgae biomass proved to be an effective biosorbent for biosorption of LVX antibiotics and may be a novel alternative method for antibiotics removal from aqueous solutions.

Albumin-templated platinum (II) sulfide nanodots for size-dependent cancer theranostics

Transition-metal chalcogenides, such as noble metal chalcogenides, hold tremendous potential as efficient agents for photo-induced cancer theranostics due to their unique physicochemical properties. However, a critical bottleneck still lies in exploring simple and controllable methods to synthesize noble metal chalcogenides especially PtS for in vivo photo-induced cancer imaging and simultaneous therapy. Herein, we proposed the albumin-templated synthesis of size-controllable platinum (II) sulfide nanodots (PtS-NDs) for multimodal cancer imaging and potent photothermal therapy. PtS-NDs were precisely synthesized with a tunable size ranging from 2.1 nm to 4.5 nm through a thermodynamically controlled growth inside albumin nanocages. PtS-NDs yielded significant near-infrared (NIR) absorbance and outstanding photothermal conversion under NIR laser irradiation, as well as effective resistance to photobleaching, thereby generating remarkable in vivo photoacoustic signals and distinct hyperthermia at tumor site. Moreover, these nanodots possessed efficient cellular uptake and tumor targeting capabilities in a size-dependent manner, thus leading to controllable diagnostic and thermo-therapeutic efficacy. Specifically, PtS-NDs with core diameter of 4.5 nm displayed preferable in vivo photoacoustic and CT imaging with high sensitivity, spatially and anatomically enhanced imaging contrast, together with hyperthermia mediated tumor ablation. Thus, the albumin-templated biomimetic synthesis provided an insightful strategy on fabricating theranostic PtS-NDs for potential clinical applications. STATEMENT OF SIGNIFICANCE: Noble metal chalcogenides especially PtS are of particular importance in the field of precise nanomedicine to improve both accuracy of cancer diagnosis and efficiency of tumor treatment. However, the intensively preclinical investigation of PtS was limited due to the lack of simple and controllable synthetic methods. Here, we report an albumin-templated biomineralization synthesis of platinum (II) sulfide nanodots (PtS-NDs). Specifically, albumin-templated biomineralization of PtS-NDs was induced by the electrostatic interactions between albumin and Pt²⁺, followed by the nucleation and growth inside the albumin nanocages. The resulting PtS-NDs showed good dispersibility and biosafety, as well as size-dependent photophysical properties and biological behaviors. Therefore, albumin-based biomineralization is a promising and safe strategy to facilely fabricate Pt-based chalcogenide for tumor theranostics.

Silica-based mesoporous ion-imprinted fluorescent sensors for the detection of Pb2+in aqueous environments

In this work, an environment-friendly core-shell material based on CDs@SiO₂as the core and mesoporous ion-imprinted layer as the shell was reported. As a highly sensitive and accurate fluorescent sensor for the detection of Pb²⁺in environmental water, the composition combined ion imprinting technology with quantum dots to selectively quench the fluorescence of CDs by metal coordination in the presence of Pb²⁺, and the visual change of gradually weakening blue color could be observed by the naked eye for visual detection. The mesoporous structure significantly improved the detection recognition rate of CDs@SiO₂@MIIPs.The molecularly imprinted sensor presented a favorable linear relationship over a Pb²⁺concentration range from 10 nmol l^-1to 100 nmol l^-1and a detection limit of 2.16 nmol l^-1for Pb²⁺. The imprinting factor of the CDs@SiO₂@MIIPs was 5.13. The sensor has a fast detection rate, is highly selective in the identification of Pb²⁺, and can be reused up to 10 times. The applicability of the method was evaluated by the determination of Pb²⁺in spiked environmental water samples with satisfactory results.

Applications of Material-Binding Peptides: A Review

Material-binding peptides (MBPs) are functionalized adhesive materials consisting of a few to several dozen amino acids. This affinity between MBPs and materials is regulated by multiple interactions, including hydrogen bonding, electrostatic, hydrophobic interactions, and π-π stacking. They show selective binding and high affinity to a diverse range of inorganic and organic materials, such as silicon-based materials, metals, metal compounds, carbon materials, and polymers. They are used to improve the biocompatibility of materials, increase the efficiency of material synthesis, and guide the controlled synthesis of nanomaterials. In addition, these can be used for precise targeting of proteins by conjugating to target biomolecules. In this review, we summarize the main designs and applications of MBPs in recent years. The discussions focus on more efficient and functional peptides, including evolution and overall design of MBPs. We have also highlighted the recent applications of MBPs, such as functionalization of material surfaces, synthesis of nanomaterials, drug delivery, cancer therapy, and plastic degradation. Besides, we also discussed the development trend of MBPs. This interpretation will accelerate future investigations to bottleneck the drawbacks of available MBPs, promoting their commercial applications.

Recent advances in biomedical applications of 2D nanomaterials with peroxidase-like properties

Significant progress has been made in developing two-dimensional (2D) nanomaterials owing to their ultra-thin structure, high specific surface area, and many other advantages. Recently, 2D nanomaterials with enzyme-like properties, especially peroxidase (POD)-like activity, are highly desirable for many biomedical applications. In this review, we first classify the types of 2D POD-like nanomaterials and then summarize various strategies for endowing 2D nanomaterials with POD-like properties. Representative examples of biomedical applications are reviewed, emphasizing in antibacterial, biosensing, and cancer therapy. Last, the future challenges and prospects of 2D POD-like nanomaterials are discussed. This review is expected to provide an in-depth understanding of 2D POD-like materials for biomedical applications.

Improving sorption performance of a molecularly imprinted monolithic column by doping mesoporous molecular sieve SBA-15

For the first time a hybrid molecularly imprinted polymer (MIP) doped with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS)-modified mesoporous molecular sieve SBA-15 for target peptide recognition has been developed. Zinc acrylate and methacrylic acid were used as binary functional monomers, and ethylene dimethacrylate was used as cross-linking agent to prepare an imprinted monolith against Val-Tyr-Ala-Leu-Lys(glutarylation) (VYALK_glu). The morphology of the polymers was characterized by scanning electron microscopy, FT-IR spectroscopy, energy dispersive spectroscopy, and ¹H NMR. The SBA-15-MPS MIP showed high recovery of 87.1% and the IF of 12.9 for the enrichment of the template peptide. When the template peptide concentration ranged from 5 to 90 μg mL^-1, the correlation coefficients (R²) for the calibration function obtained was better 0.999. The limit of detection (LOD, 0.30 μg mL^-1) and limit of quantification (LOQ, 1.0 μg mL^-1) were achieved for signal-to-noise ratios of 3:1 and 10:1, respectively. When other kinds of synthetic peptides were used as analogs, the selectivity of the SBA-15-MPS MIP was much better than the SBA-15-MPS NIP (without template peptides) with relative selectivity coefficients of 52.8-265. In contrast, little quinolones and biogenic amines are adsorbed with the SBA-15-MPS MIP. The SBA-15-MPS MIP could enrich VYALK_glu from spiked histone digestion with the average recovery of 87.8% and the relative standard deviation (RSD) of 0.99%. As a conclusion, doping of SBA-15 is an effective approach to the improvement of performance of molecularly imprinted monolith.

Remediation of pharmaceuticals from contaminated water by molecularly imprinted polymers: a review

The release of pharmaceuticals into the environment induces adverse effects on the metabolism of humans and other living species, calling for advanced remediation methods. Conventional removal methods are often non-selective and cause secondary contamination. These issues may be partly solved by the use of recently-developped adsorbents such as molecularly imprinted polymers. Here we review the synthesis and application of molecularly imprinted polymers for removing pharmaceuticals in water. Molecularly imprinted polymers are synthesized via several multiple-step polymerization methods. Molecularly imprinted polymers are potent adsorbents at the laboratory scale, yet their efficiency is limited by template leakage and polymer quality. Adsorption performance of multi-templated molecularly imprinted polymers depends on the design of wastewater treatment plants, pharmaceutical consumption patterns and the population serviced by these wastewater treatment plants.

Construction of DNA ligase-mimicking nanozymes via molecular imprinting

Enzyme mimics are of significant importance due to their facile preparation, low cost and stability to rigorous environment. Molecularly imprinted polymers (MIPs) have been important synthetic mimics of enzymes. However,...

The Use of Computational Methods for the Development of Molecularly Imprinted Polymers

Recent years have witnessed a dramatic increase in the use of theoretical and computational approaches in the study and development of molecular imprinting systems. These tools are being used to either improve understanding of the mechanisms underlying the function of molecular imprinting systems or for the design of new systems. Here, we present an overview of the literature describing the application of theoretical and computational techniques to the different stages of the molecular imprinting process (pre-polymerization mixture, polymerization process and ligand-molecularly imprinted polymer rebinding), along with an analysis of trends within and the current status of this aspect of the molecular imprinting field.

A porous organic polymer nanosphere-based fluorescent biosensing platform for simultaneous detection of multiplexed DNA via electrostatic attraction and π–π stacking interactions

One key challenge in oligonucleotide sequence sensing is to achieve multiplexed DNA detection in one sensor. Herein, a simple and efficient fluorescent biosensing platform is constructed to simultaneously detect multiplexed DNA depending on porous organic polymer (POP) nanospheres. The developed sensor is based on the concept that the POP nanospheres can efficiently quench the fluorescence emission of dye-labeled single-stranded DNA (ssDNA). Fluorescence quenching is achieved by the non-covalent assembly of multiple probes on the surface of POP nanospheres through electrostatic attraction and π–π stacking interactions, in which the electrostatic attraction plays a more critical role than π–π stacking. The formed dsDNA could be released off the surface of POP via hybridizing with the target DNA. Consequently, the target DNA can be quickly detected by fluorescence recovery. The biosensor could sensitively and specifically identify three target DNAs in the range of 0.1 to 36 nM, and the lowest detection limits are 50 pM, 100 pM, and 50 pM, respectively. It is noteworthy that the proposed platform is successfully applied to detect DNA in human serum. We perceive that the proposed sensing system represents a simple and sensitive strategy towards simultaneous and multiplexed assays for DNA monitoring and early clinical diagnosis.

This communication reports a simple and efficient fluorescent biosensing platform to simultaneously detect multiplexed DNA depending on porous organic polymer (POP) nanospheres by electrostatic attraction and π–π stacking interaction.

Overcoming blood-brain barrier transport: Advances in nanoparticle-based drug delivery strategies

The Blood-Brain Barrier (BBB), a unique structure in the central nervous system (CNS), protects the brain from bloodborne pathogens by its excellent barrier properties. Nevertheless, this barrier limits therapeutic efficacy and becomes one of the biggest challenges in new drug development for neurodegenerative disease and brain cancer. Recent breakthroughs in nanotechnology have resulted in various nanoparticles (NPs) as drug carriers to cross the BBB by different methods. This review presents the current understanding of advanced NP-mediated non-invasive drug delivery for the treatment of neurological disorders. Herein, the complex compositions and special characteristics of BBB are elucidated exhaustively. Moreover, versatile drug nanocarriers with their recent applications and their pathways on different drug delivery strategies to overcome the formidable BBB obstacle are briefly discussed. In terms of significance, this paper provides a general understanding of how various properties of nanoparticles aid in drug delivery through BBB and usher the development of novel nanotechnology-based nanomaterials for cerebral disease therapies.

Protein-Based Artificial Nanosystems in Cancer Therapy

Proteins, like actors, play different roles in specific applications. In the past decade, significant achievements have been made in protein-engineered biomedicine for cancer therapy. Certain proteins such as human serum albumin, working as carriers for drug/photosensitizer delivery, have entered clinical use due to their long half-life, biocompatibility, biodegradability, and inherent nonimmunogenicity. Proteins with catalytic abilities are promising as adjuvant agents for other therapeutic modalities or as anticancer drugs themselves. These catalytic proteins are usually defined as enzymes with high biological activity and substrate specificity. However, clinical applications of these kinds of proteins remain rare due to protease-induced denaturation and weak cellular permeability. Based on the characteristics of different proteins, tailor-made protein-based nanosystems could make up for their individual deficiencies. Therefore, elaborately designed protein-based nanosystems, where proteins serve as drug carriers, adjuvant agents, or therapeutic drugs to make full use of their intrinsic advantages in cancer therapy, are reviewed. Up-to-date progress on research in the field of protein-based nanomedicine is provided.

Highly selective surface adsorption-induced efficient photodegradation of cationic dyes on hierarchical ZnO nanorod-decorated hydrolyzed PIM-1 nanofibrous webs

Selectivity of catalysts toward harmful cationic pollutants in industrial wastewater remains challenging but is of crucial importance in environmental remediation processes. Here, we present a complex network of a hydrolyzed polymer of intrinsic microporosity (HPIM)-based electrospun nanofibrous web with surface functional decoration of ZnO nanorods (NRs) as a hierarchical platform for selective and rapid degradation of cationic dyes. Over a single species or binary mixtures, cationic dyes were selectively adsorbed by the HPIM surface, which then rapidly degraded under simultaneous photoirradiation through the ZnO NRs. Both HPIM and ZnO exhibited high electronegative surfaces, which induced the selectivity towards the cationic dyes and rapidly degraded the pollutants with the production of reactive oxygen species under photoirradiation. Further, as a free-standing web, the catalytic network could be easily separated and reused without any significant loss of catalytic activity after multiple cycles of use. The hierarchical platform of ZnO/HPIM-based heterostructures could be a promising catalytic template for selective degradation of synthetic dyes in mixed wastewater samples.

Integrating ionic liquids with molecular imprinting technology for biorecognition and biosensing: A review

As promising alternatives to natural receptors, artificial molecularly imprinted polymers (MIPs) have received great attention in biotechnology. Nevertheless, some bottlenecks limit their further development, including low adsorption capacity, poor recognition efficiency, slow response, and insipid aqueous compatibility. Ionic liquids (ILs) show the features of tailored structures and properties, high conductivity, good solubility, and excellent stability. Because of these advantages, they have found intensive use in MIPs by remedying the latter's shortcomings. In this review, we summarize the integration of ILs and MIPs for biorecognition and biosensing. The versatile roles of ILs in improving the performance of MIPs are firstly summarized, including serving as solvents, porogens, functional monomers, organic surface modifiers, dummy templates, and cross-linkers. Then, specific applications of IL-based MIPs in peptide recognition, protein sensing, and food safety analysis are discussed. Finally, future trends and challenges for the design and development of IL-based MIPs and their applications in the biorecognition and biosensing are proposed.

Molecularly Imprinted Materials for Selective Biological Recognition

Molecular imprinting is an approach of generating imprinting cavities in polymer structures that are compatible with the target molecules. The cavities have memory for shape and chemical recognition, similar to the recognition mechanism of antigen-antibody in organisms. Their structures are also called biomimetic receptors or synthetic receptors. Owing to the excellent selectivity and unique structural predictability of molecularly imprinted materials (MIMs), practical MIMs have become a rapidly evolving research area providing key factors for understanding separation, recognition, and regenerative properties toward biological small molecules to biomacromolecules, even cell and microorganism. In this review, the characteristics, morphologies, and applicability of currently popular carrier materials for molecular imprinting, especially the fundamental role of hydrogels, porous materials, hierarchical nanoparticles, and 2D materials in the separation and recognition of biological templates are discussed. Moreover, through a series of case studies, emphasis is given on introducing imprinting strategies for biological templates with different molecular scales. In particular, the differences and connections between small molecular imprinting (bulk imprinting, "dummy" template imprinting, etc.), large molecular imprinting (surface imprinting, interfacial imprinting, etc.), and cell imprinting strategies are demonstrated in detail. Finally, future research directions are provided.

Convenient synthesis of uncovered imprinted microspheres by Ganoderma lucidum spore-stabilized pickering emulsion polymerization and their enhanced recognition of spiramycin

In this work, a new and simple method was developed for the synthesis of uncovered and high-selectivity spiramycin-based molecularly imprinted microspheres (SP-MIMs) by Pickering emulsion polymerization using spiramycin as templates. And surprisingly the solid particles were absent on the surface of imprinted microspheres, which can be ascribed to the Ganoderma lucidum spores (GLS): they were firstly selected to be the stabilizers for the Pickering emulsion in this new strategy. Through a series of adsorption experiments, the uncovered SP-MIMs were proven to possess more excellent selective recognition and removal ability for template SP in aqueous solution. And SP-MIMs could be reused for many times without significant loss of adsorption capacity, indicating the satisfactory regeneration performance. Therefore, SP-MIMs can be employed as a promising adsorbent for the selective removal of SP from aqueous media, and this strategy will contribute to overcoming the shortcomings of stabilizer particles on the surface of the as-prepared imprinting microspheres, because these solid particles lack the special selective recognition activity of template molecules, and may disturb the adsorption effect of imprinting microspheres.

In this work, a new and simple method was developed for the synthesis of uncovered and high-selectivity spiramycin-based molecularly imprinted microspheres (SP-MIMs) by Pickering emulsion polymerization using spiramycin as templates.