Temperature and magnetism bi-responsive molecularly imprinted polymers: Preparation, adsorption mechanism and properties as drug delivery system for sustained release of 5-fluorouracil

Antibacterial and Osteogenic Doxycycline Imprinted Bioglass Microspheres to Combat Bone Infection

Currently, postoperative infection is a significant challenge in bone and dental surgical procedures, demanding the exploration of innovative approaches due to the prevalence of antibiotic-resistant bacteria. This study aims to develop a strategy for controlled and smart antibiotic release while accelerating osteogenesis to expedite bone healing. In this regard, temperature-responsive doxycycline (DOX) imprinted bioglass microspheres (BGMs) were synthesized. Following the formation of chitosan-modified BGMs, poly N-isopropylacrylamide (pNIPAm) was used for surface imprinting of DOX. The temperature-responsive molecularly imprinted polymers (MIPs) exhibited pH and temperature dual-responsive adsorption and controlled-release properties for DOX. The temperature-responsive MIP was optimized by investigating the molar ratio of N,N'-methylene bis(acrylamide) (MBA, the cross-linker) to NIPAm. Our results demonstrated that the MIPs showed superior adsorption capacity (96.85 mg/g at 35 °C, pH = 7) than nonimprinted polymers (NIPs) and manifested a favorable selectivity toward DOX. The adsorption behavior of DOX on the MIPs fit well with the Langmuir model and the pseudo-second-order kinetic model. Drug release studies demonstrated a controlled release of DOX due to imprinted cavities, which were fitted with the Korsmeyer-Peppas kinetic model. DOX-imprinted BGMs also revealed comparable antibacterial effects against Staphylococcus aureus and Escherichia coli to the DOX (control). In addition, MIPs promoted viability and osteogenic differentiation of MG63 osteoblast-like cells. Overall, the findings demonstrate the significant potential of DOX-imprinted BGMs for use in bone defects. Nonetheless, further in vitro investigations and subsequent in vivo experiments are warranted to advance this research.

Molecularly Imprinted Carriers for Diagnostics and Therapy-A Critical Appraisal

Simultaneous diagnostics and targeted therapy provide a theranostic approach, an instrument of personalized medicine-one of the most-promising trends in current medicine. Except for the appropriate drug used during the treatment, a strong focus is put on the development of effective drug carriers. Among the various materials applied in the production of drug carriers, molecularly imprinted polymers (MIPs) are one of the candidates with great potential for use in theranostics. MIP properties such as chemical and thermal stability, together with capability to integrate with other materials are important in the case of diagnostics and therapy. Moreover, the MIP specificity, which is important for targeted drug delivery and bioimaging of particular cells, is a result of the preparation process, conducted in the presence of the template molecule, which often is the same as the target compound. This review focused on the application of MIPs in theranostics. As a an introduction, the current trends in theranostics are described prior to the characterization of the concept of molecular imprinting technology. Next, a detailed discussion of the construction strategies of MIPs for diagnostics and therapy according to targeting and theranostic approaches is provided. Finally, frontiers and future prospects are presented, stating the direction for further development of this class of materials.

Molecularly imprinted polymers (MIPs): emerging biomaterials for cancer theragnostic applications

Cancer is a disease caused by abnormal cell growth that spreads through other parts of the body and threatens life by destroying healthy tissues. Therefore, numerous techniques have been employed not only to diagnose and monitor the progress of cancer in a precise manner but also to develop appropriate therapeutic agents with enhanced efficacy and safety profiles. In this regard, molecularly imprinted polymers (MIPs), synthetic receptors that recognize targeted molecules with high affinity and selectivity, have been intensively investigated as one of the most attractive biomaterials for theragnostic approaches. This review describes diverse synthesis strategies to provide the rationale behind these synthetic antibodies and provides a selective overview of the recent progress in the in vitro and in vivo targeting of cancer biomarkers for diagnosis and therapeutic applications. Taken together, the topics discussed in this review provide concise guidelines for the development of novel MIP-based systems to diagnose cancer more precisely and promote successful treatment. Molecularly imprinted polymers (MIPs), synthetic receptors that recognize targeted molecules with high affinity and selectivity, have been intensively investigated as one of the most attractive biomaterials for cancer theragnostic approaches. This review describes diverse synthesis strategies to provide the rationale behind these synthetic antibodies and provides a selective overview of the recent progress in the in vitro and in vivo targeting of cancer biomarkers for diagnosis and therapeutic applications. The topics discussed in this review aim to provide concise guidelines for the development of novel MIP-based systems to diagnose cancer more precisely and promote successful treatment.

Development of an Fe3O4 Surface-Grafted Carboxymethyl Chitosan Molecularly Imprinted Polymer for Specific Recognition and Sustained Release of Salidroside

The choice of carrier material is critical in the study of natural drug release preparations and glycosylated magnetic molecularly imprinted materials. The stiffness and softness of the carrier material affect the efficiency of drug release and the specificity of recognition. The dual adjustable aperture-ligand in molecularly imprinted polymers (MIPs) provides the possibility of individualized design for sustained release studies. In this study, a combination of paramagnetic Fe₃O₄ and carboxymethyl chitosan (CC) was used to enhance the imprinting effect and improve drug delivery. A combination of tetrahydrofuran and ethylene glycol was used as a binary porogen to prepare MIP-doped Fe₃O₄-grafted CC (SMCMIP). Salidroside serves as the template, methacrylic acid acts as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) serves as the crosslinker. Scanning and transmission electron microscopy were used to observe the micromorphology of the microspheres. The structural and morphological parameters of the SMCMIP composites were measured, including the surface area and pore diameter distribution. In an in vitro study, we found that the SMCMIP composite had a sustained release property of 50% after 6 h of release time in comparison to the control SMCNIP. The total amounts of SMCMIP released at 25 °C and 37 °C were 77% and 86%, respectively. In vitro results showed that the release of SMCMIP followed Fickian kinetics, meaning that the rate of release is dependent on the concentration gradient, with diffusion coefficients ranging from 3.07 × 10^-2 cm²/s to 5.66 × 10^-3 cm²/s. The results of cytotoxicity experiments showed that the SMCMIP composite did not have any harmful effects on cell growth. The survival rates of intestinal epithelial cells (IPEC-J2) were found to be above 98%. By using the SMCMIP composite, drugs may be delivered in a sustained manner, potentially leading to improved therapeutic outcomes and reduced side effects.

In Vivo Applications of Molecularly Imprinted Polymers for Drug Delivery: A Pharmaceutical Perspective

Molecularly imprinted polymers (MIPs) have been proven to be a promising candidate for drug delivery systems (DDS) due to their ability to provide a sustained and controlled drug release, making them useful for treating a wide range of medical conditions. MIP-based DDS offer many advantages, including the administration of a smaller drug doses, due to the higher drug payload or targeted delivery, resulting in fewer side effects, as well as the possibility of attaining high concentrations of the drug in the targeted tissues. Whether designed as drug reservoirs or targeted DDS, MIPs are of great value to drug delivery as conventional drug formulations can be redesigned as DDS to overcome the active pharmaceutical ingredient's (APIs) poor bioavailability, toxic effects, or other shortcomings that previously made them less efficient or unsuitable for therapy. Therefore, MIP design could be a promising alternative to the challenging research and development of new lead compounds. Research on MIPs is primarily conducted from a material science perspective, which often overlooks some of their key pharmaceutical requirements. In this review, we emphasize the specific features that make MIPs suitable for clinical use, from both a material science and a biopharmaceutical perspective.

β-Cyclodextrin-Based Supramolecular Imprinted Fiber Array for Highly Selective Detection of Parabens

A novel high-throughput array analytical platform based on derived β-cyclodextrin supramolecular imprinted polymer (SMIP) fibers was constructed to achieve selective enrichment and removal of parabens. SMIP fiber arrays have abundant imprinting sites and introduce the host−guest inclusion effect of the derived β-cyclodextrin, which is beneficial to significantly improve the adsorption ability of fiber for parabens. Upon combination with HPLC, a specific and sensitive recognition method was developed with a low limit of detection (0.003−0.02 µg/L, S/N = 3) for parabens analysis in environmental water. This method has a good linearity (R > 0.9994) in the linear range of 0.01−200 µg/L. The proposed SMIP fiber array with high-throughput adsorption capacity has great potential in monitoring water pollution, which also provides a reliable reference for the analysis of more categories of pharmaceutical and personal care product pollutants.

Poly(N-isopropylacrylamide)-Based Hydrogels for Biomedical Applications: A Review of the State-of-the-Art

A prominent research topic in contemporary advanced functional materials science is the production of smart materials based on polymers that may independently adjust their physical and/or chemical characteristics when subjected to external stimuli. Smart hydrogels based on poly(N-isopropylacrylamide) (PNIPAM) demonstrate distinct thermoresponsive features close to a lower critical solution temperature (LCST) that enhance their capability in various biomedical applications such as drug delivery, tissue engineering, and wound dressings. Nevertheless, they have intrinsic shortcomings such as poor mechanical properties, limited loading capacity of actives, and poor biodegradability. Formulation of PNIPAM with diverse functional constituents to develop hydrogel composites is an efficient scheme to overcome these defects, which can significantly help for practicable application. This review reports on the latest developments in functional PNIPAM-based smart hydrogels for various biomedical applications. The first section describes the properties of PNIPAM-based hydrogels, followed by potential applications in diverse fields. Ultimately, this review summarizes the challenges and opportunities in this emerging area of research and development concerning this fascinating polymer-based system deep-rooted in chemistry and material science.

Molecularly imprinted polymers: preparation, characterisation, and application in drug delivery systems

Molecular imprinting technology defines the creation of molecularly imprinted polymer (MIP) molecules in which template molecules can place in a key-lock relationship through shape, diameter, and functional groups. Although molecular imprinting technology has been employed in different fields, its applications in drug delivery systems (DDSs) have gained momentum recently. The high loading efficiency, high stability, and controlled drug release are the primary advantages of MIPs. Here, the main components, preparation methods, and characterisation tests of MIPs are summarised, and their applications in DDSs administered by different routes are evaluated in detail. The review offers a perspective on molecular imprinting technology and applications of MIPs in drug delivery by surveying the literature approximately 1998-2021 together with the outlined prospects.

EGDMA- and TRIM-Based Microparticles Imprinted with 5-Fluorouracil for Prolonged Drug Delivery

Imprinted materials possess designed cavities capable of forming selective interactions with molecules used in the imprinting process. In this work, we report the synthesis of 5-fluorouracil (5-FU)-imprinted microparticles and their application in prolonged drug delivery. The materials were synthesized using either ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TRIM) cross-linkers. For both types of polymers, methacrylic acid was used as a functional monomer, whereas 2-hydroxyethyl methacrylate was applied to increase the final materials’ hydrophilicity. Adsorption isotherms and adsorption kinetics were investigated to characterize the interactions that occur between the materials and 5-FU. The microparticles synthesized using the TRIM cross-linker showed higher adsorption properties towards 5-FU than those with EGDMA. The release kinetics was highly dependent upon the cross-linker and pH of the release medium. The highest cumulative release was obtained for TRIM-based microparticles at pH 7.4. The IC₅₀ values proved that 5-FU-loaded TRIM-based microparticles possess cytotoxic activity against HeLa cell lines similar to pure 5-FU, whereas their toxicity towards normal HDF cell lines was ca. three times lower than for 5-FU.

Transfersome Hydrogel Containing 5-Fluorouracil and Etodolac Combination for Synergistic Oral Cancer Treatment

Oral cancer is one of the most common malignancies with an increased rate of incidence. 5-Fluorouracil (5FU) is an effective chemotherapeutic indicated for oral cancer treatment. Etodolac (Et), a cyclooxygenase-2 inhibitor, can be used as an adjuvant agent to sensitize cancer cells to chemotherapy. The aim of this work was to prepare and characterize 5FU and Et dual drug-loaded transfersomes to treat oral cancer. Transfersomes were prepared by thin-film hydration method and characterized for the average particle size and zeta-potential using dynamic light scattering and scanning electron microscopy techniques. The prepared transfersomes were further characterized for their drug loading, entrapment efficiencies using amicon centrifuge tubes and drug release behavior using cellulose membrane. The synergistic activity of dual drug-loaded transfersomes was studied in FaDu oral cancer cells. Results showed that the average particle size, polydispersity index, and zeta potential were 91±6.4 nm, 0.28±0.03, and (-)46.9±9.5 mV, respectively, for 5FU- and Et (1:1)-loaded transfersomes. The highest encapsulation efficiency achieved was 36.9±3.8% and 79.8±6.4% for 5FU and Et (1:1), respectively. Growth inhibition studies in FaDu cells using different concentrations of 5FU and Et showed a combination index of 0.36, indicating a synergistic effect. The FaDu cell uptake of drug-loaded transfersomes was significantly (p<0.05) greater than that of free drugs. The transfersome hydrogel made of HPMC (2% w/w) showed similar flux, lag time, and permeation coefficient as that of drug-loaded transfersomes across excised porcine buccal tissue. In conclusion, 5FU and Et transfersome hydrogel can be developed for localized delivery to treat oral cancer.

Nano-molecularly imprinted polymers (nanoMIPs) as a novel approach to targeted drug delivery in nanomedicine

Molecularly imprinted polymers - MIPs - denote synthetic polymeric structures that selectively recognize the molecule of interest against which MIPs are templated. A number of works have demonstrated that MIPs can exceed the affinity and selectivity of natural antibodies, yet operating by the same principle of "lock and key". In contrast to antibodies, which have certain limitations related to the minimal size of the antigen, nanoMIPs can be fabricated against almost any target molecule irrespective of its size and low immunogenicity. Furthermore, the cost of MIP production is much lower compared to the cost of antibody production. Excitingly, MIPs can be used as nanocontainers for specific delivery of therapeutics both in vitro and in vivo. The adoption of the solid phase synthesis rendered MIPs precise reproducible characteristics and, as a consequence, improved the controlled release of therapeutic payloads. These major breakthroughs paved the way for applicability of MIPs in medicine as a novel class of therapeutics. In this review, we highlight recent advances in the fabrication of MIPs, mechanisms of controlled release from the MIPs, and their applicability in biomedical research.

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 Review on Molecularly Imprinted Polymers Preparation by Computational Simulation-Aided Methods

Molecularly imprinted polymers (MIPs) are obtained by initiating the polymerization of functional monomers surrounding a template molecule in the presence of crosslinkers and porogens. The best adsorption performance can be achieved by optimizing the polymerization conditions, but this process is time consuming and labor-intensive. Theoretical calculation based on calculation simulations and intermolecular forces is an effective method to solve this problem because it is convenient, versatile, environmentally friendly, and inexpensive. In this article, computational simulation modeling methods are introduced, and the theoretical optimization methods of various molecular simulation calculation software for preparing molecularly imprinted polymers are proposed. The progress in research on and application of molecularly imprinted polymers prepared by computational simulations and computational software in the past two decades are reviewed. Computer molecular simulation methods, including molecular mechanics, molecular dynamics and quantum mechanics, are universally applicable for the MIP-based materials. Furthermore, the new role of computational simulation in the future development of molecular imprinting technology is explored.

Advances in chlorin-based photodynamic therapy with nanoparticle delivery system for cancer treatment

Introduction: The treatment of tumors is one of the most difficult problems in the medical field at present. Patients often use a comprehensive therapy that combines surgery, radiotherapy, and chemotherapy. Photodynamic therapy (PDT) has prominent potential for eradicating various cancers. Chlorin-based photosensitizers (PSs), as one of the most utilized photosensitizers, have many advantages over conventional photosensitizers; however, a successful chlorin-based PDT needs multi-functional nano-carriers for selective photosensitizer delivery. The number of researches about nanoparticles designed for improved chlorin-based PSs is increasing in the current era. In this article, we give a brief review focused on the recent research progress in design of chlorin-based nanoparticles for the treatment of malignant tumors with photodynamic therapy.Areas covered: This review focuses on the current nanoparticle platforms for PDT, and describes different strategies to achieve controllable PDT by chlorin-nano-delivery systems. The challenges and prospects of PDT in clinical applications are also discussed.Expert opinions: The requirement for PDT to eradicate cancers has increased exponentially in recent years. The major clinically used photosensitizers are hydrophobic. The main obstacles in effective delivery of PSs are associated with this intrinsic nature. The design of nano-delivery systems to load PSs is pivotal for PSs' widespread use.

Advances in Molecularly Imprinted Polymers as Drug Delivery Systems

Despite the tremendous efforts made in the past decades, severe side/toxic effects and poor bioavailability still represent the main challenges that hinder the clinical translation of drug molecules. This has turned the attention of investigators towards drug delivery vehicles that provide a localized and controlled drug delivery. Molecularly imprinted polymers (MIPs) as novel and versatile drug delivery vehicles have been widely studied in recent years due to the advantages of selective recognition, enhanced drug loading, sustained release, and robustness in harsh conditions. This review highlights the design and development of strategies undertaken for MIPs used as drug delivery vehicles involving different drug delivery mechanisms, such as rate-programmed, stimuli-responsive and active targeting, published during the course of the past five years.

Dynamic Tannic Acid Hydrogel with Self-Healing and pH Sensitivity for Controlled Release

Dynamic hydrogels constructed with dynamic chemical bonds often have mechanical strength and self-healing properties. In this paper, tannic acid is combined with lysine-containing F127 through Schiff base. A series of FLaT hydrogels cross-linked by hydrogen bonds and dynamic chemical bonds is prepared, and the influence of Schiff base amount on the performance is discussed. The FLaT hydrogel exhibits reversible sol-gel transition, self-healing, injectability, and pH sensitivity. Increasing the amount of Schiff base can improve the strength, stability, and self-healing ability of the hydrogel. Owing to their low cytotoxicity, linear release pattern, and pH-controlled release rate, the FLaT hydrogels show potential use in drug delivery systems for cancer treatment.

Thermally induced and physically cross-linked hydrogel doped with graphene oxide for controlled release

Graphene oxide (GO) is an ideal hydrogel material because of its water solubility, non-toxicity, and excellent mechanical properties. Here, we added GO to oligo(lysine)-modified F127 to prepare a series of FLGO composite hydrogels. The FLGO hydrogel was thermally induced, stable and injectable. And the content of GO would affect the sol-gel transition, rheological properties and glass transition temperature of the FLGO hydrogel. GO was connected to the matrix through electrostatic interactions and hydrogen bonds. The cross-linking effect of GO enhanced the FLGO hydrogel. We also studied the release properties of the FLGO hydrogel loaded with anticancer drug 5-fluorouracil. Compared with F127 hydrogel, the FLGO hydrogel showed a linear, slower and stable release pattern within one week. The release rate of FLGO hydrogel could be adjusted by the pH and it was faster under acidic conditions. Therefore, the FLGO hydrogel is expected to be used as a drug release system in the field of biomedicine.

Molecularly Imprinted Polymer Nanoparticles: An Emerging Versatile Platform for Cancer Therapy

Molecularly imprinted polymers (MIPs) are chemically synthesized affinity materials with tailor-made binding cavities complementary to the template molecules in shape, size, and functionality. Recently, engineering MIP-based nanomedicines to improve cancer therapy has become a rapidly growing field and future research direction. Because of the unique properties and functions of MIPs, MIP-based nanoparticles (nanoMIPs) are not only alternatives to current nanomaterials for cancer therapy, but also hold the potential to fill gaps associated with biological ligand-based nanomedicines, such as immunogenicity, stability, applicability, and economic viability. Here, we survey recent advances in the design and fabrication of nanoMIPs for cancer therapy and highlight their distinct features. In addition, how to use these features to achieve desired performance, including extended circulation, active targeting, controlled drug release and anti-tumor efficacy, is discussed and summarized. We expect that this minireview will inspire more advanced studies in MIP-based nanomedicines for cancer therapy.

Selective and rapid removal of Mo(VI) from water using functionalized Fe3O4-based Mo(VI) ion-imprinted polymer

Fe₃O₄ nanoparticles-based magnetic Mo(VI) surface ion-imprinted polymer (Mo(VI)-MIIP) was elaborated employing 4-vinyl pyridine as a functional monomer. The adsorbent preparation was confirmed by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, vibrating sample magnetometer, thermogravimetric analysis, and surface area analysis. Batch adsorption experiments showed that the maximum adsorption capacity of Mo(VI)-MIIP was 296.40 mg g^-1 at pH 3, while that of the magnetic non-imprinted polymer (MNIP) was only 147.10 mg g^-1. The adsorption isotherm model was well fitted by the Langmuir isotherm model. The adsorption experiments revealed that Mo(VI)-MIIP reached adsorption equilibrium within 30 min, and the kinetics data fitting showed that the pseudo-second-order kinetics model suitably described the adsorption process. Mo(VI)-MIIP exhibited an excellent adsorption selectivity to Mo(VI) in binary mixtures of Mo(VI)/Cr(VI), Mo(VI)/Cu(II), Mo(VI)/H₂PO4₄^-, Mo(VI)/Zn(II), and Mo(VI)/I^-, with relative selectivity coefficients toward MNIP of 13.71, 30.27, 20.01, 23.53, and 15.89, respectively. After six consecutive adsorption-desorption cycles, the adsorption capacity of Mo(VI)-MIIP decreased by 9.5% (from 228.4 mg g^-1 to 206.7 mg g^-1 at initial Mo(VI) concentration of 250 mg L^-1), demonstrating its reusability.

Molecularly imprinted polymers in biological applications

Molecularly imprinted polymers (MIPs) are currently widely used and further developed for biological applications. The MIP synthesis procedure is a key process, and a wide variety of protocols exist. The templates that are used for imprinting vary from the smallest glycosylated glycan structures or even amino acids to whole proteins or bacteria. The low cost, quick preparation, stability and reproducibility have been highlighted as advantages of MIPs. The biological applications utilizing MIPs discussed here include enzyme-linked assays, sensors, in vivo applications, drug delivery, cancer diagnostics and more. Indeed, there are numerous examples of how MIPs can be used as recognition elements similar to natural antibodies.

Developments of Smart Drug-Delivery Systems Based on Magnetic Molecularly Imprinted Polymers for Targeted Cancer Therapy: A Short Review

Cancer therapy is still a huge challenge, as especially chemotherapy shows several drawbacks like low specificity to tumor cells, rapid elimination of drugs, high toxicity and lack of aqueous solubility. The combination of molecular imprinting technology with magnetic nanoparticles provides a new class of smart hybrids, i.e., magnetic molecularly imprinted polymers (MMIPs) to overcome limitations in current cancer therapy. The application of these complexes is gaining more interest in therapy, due to their favorable properties, namely, the ability to be guided and to generate slight hyperthermia with an appropriate external magnetic field, alongside the high selectivity and loading capacity of imprinted polymers toward a template molecule. In cancer therapy, using the MMIPs as smart-drug-delivery robots can be a promising alternative to conventional direct administered chemotherapy, aiming to enhance drug accumulation/penetration into the tumors while fewer side effects on the other organs. Overview: In this review, we state the necessity of further studies to translate the anticancer drug-delivery systems into clinical applications with high efficiency. This work relates to the latest state of MMIPs as smart-drug-delivery systems aiming to be used in chemotherapy. The application of computational modeling toward selecting the optimum imprinting interaction partners is stated. The preparation methods employed in these works are summarized and their attainment in drug-loading capacity, release behavior and cytotoxicity toward cancer cells in the manner of in vitro and in vivo studies are stated. As an essential issue toward the development of a body-friendly system, the biocompatibility and toxicity of the developed drug-delivery systems are discussed. We conclude with the promising perspectives in this emerging field. Areas covered: Last ten years of publications (till June 2020) in magnetic molecularly imprinted polymeric nanoparticles for application as smart-drug-delivery systems in chemotherapy.

Molecularly Imprinting Polymers (MIP) Based on Nitrogen Doped Carbon Dots and MIL-101(Fe) for Doxorubicin Hydrochloride Delivery

MIL-based molecularly imprinted polymer (MIP) nanocomposites were successfully synthesized through a simple and versatile stirring auxiliary encapsulation method. MIP as a carrier has been applied to the highly efficient selective recognition and sustained release of doxorubicin hydrochloride (DOX). The adsorption mechanism and release behavior of MIP@DOX in vitro were also discussed. Adsorption studies showed that MIP using DOX as template had specific selectivity to DOX, and its optimal drug loading efficiency reached 97.99%. The adsorption isotherm accorded with Freundlich models. The cumulative release curve showed that at the conditions of pH 5.5 and 7.4, the nanomaterials have a slow-release effect on the release of DOX. In addition, the cytotoxicity and bioactivity of MIP nanoparticles on HepG2 and HL-7702 cell lines measured by MTT assay also proved their low toxicity and biological activity. The cell activity of HepG2 and HL-7702 incubated with MIP for 24 h was 69.9% and 76.07%, respectively. These results collectively illustrated that the MIP nano-materials synthesized in this study can be efficiently employed to the drug delivery systems.

Recent Advances in Designing 5-Fluorouracil Delivery Systems: A Stepping Stone in the Safe Treatment of Colorectal Cancer

5-Fluorouracil (5-FU) has become one of the most widely employed antimetabolite chemotherapeutic agents in recent decades. It is considered a first line antineoplastic agent for the treatment of colorectal cancer. Unfortunately, chemotherapy with 5-FU has several limitations, including its short half-life, high cytotoxicity and low bioavailability. In order to overcome the drawbacks of 5-FU and enhance its therapeutic efficiency, many scientific groups have focused on designing a new delivery system to successfully deliver 5-FU to tumor sites. We provide a comprehensive review on different strategies to design effective delivery systems, including nanoformulations, drug-conjugate formulations and other strategies for the delivery of 5-FU to colorectal cancer. Furthermore, co-delivery of 5-FU with other therapeutics is discussed. This review critically highlights the recent innovations in and literature on various types of carrier system for 5-FU.

Molecularly Imprinted Synthetic Antibodies: From Chemical Design to Biomedical Applications

Billions of dollars are invested into the monoclonal antibody market every year to meet the increasing demand in clinical diagnosis and therapy. However, natural antibodies still suffer from poor stability and high cost, as well as ethical issues in animal experiments. Thus, developing antibody substitutes or mimics is a long-term goal for scientists. The molecular imprinting technique presents one of the most promising strategies for antibody mimicking. The molecularly imprinted polymers (MIPs) are also called "molecularly imprinted synthetic antibodies" (MISAs). The breakthroughs of key technologies and innovations in chemistry and material science in the last decades have led to the rapid development of MISAs, and their molecular affinity has become comparable to that of natural antibodies. Currently, MISAs are undergoing a revolutionary transformation of their applications, from initial adsorption and separation to the rising fields of biomedicine. Herein, the fundamental chemical design of MISAs is examined, and then current progress in biomedical applications is the focus. Meanwhile, the potential of MISAs as qualified substitutes or even to transcend the performance of natural antibodies is discussed from the perspective of frontier needs in biomedicines, to facilitate the rapid development of synthetic artificial antibodies.

Selective Targeted Drug Delivery Mechanism via Molecular Imprinted Polymers in Cancer Therapeutics

Artificial receptor-like structures such as molecular imprinted polymers (MIPs) are biomimetic molecules are used to replicate target specific antibody-antigen mechanism. In MIPs, selective binding of template molecule can be significantly correlated with lock and key mechanism, which play a major role in the drug delivery mechanism. The MIPs are biocompatible with high efficiency and are considered in several drug delivery and biosensor applications besides continuous and controlled drug release leading to better therapeutics. There is a need to explore the potential synthetic methods to improve MIPs with respect to the imprinting capacity in cancer therapeutics. In this review, we focus on MIPs as drug delivery mechanism in cancer and the challenges related to their synthesis and applications.

Dual responsive oligo(lysine)-modified Pluronic F127 hydrogels for drug release of 5-fluorouracil

Peptide-containing hydrogels have become a research hotspot due to their unique secondary structure and biocompatibility. Herein, we used amino-terminated F127 as a macroinitiator to initiate the ring-opening polymerization of l-lysine(z)-NCA, and the obtained oligo(lysine)-modified F127 (FL) had degrees of polymerization of lysine of 2, 5, and 8. The results showed that the FL hydrogels had reversible temperature-dependent sol–gel transitions, and the introduction of lysine increased the critical gel temperature. In the dilute solution of FL, the micelle size increased and aggregated as the pH increased; the micelle grew into a rod-like shape under alkaline conditions. Scanning electron micrographs showed that the interior of the FL hydrogel had a more complete porous structure. The FL-2 hydrogel loaded with 5-fluorouracil exhibited an approximately linear release trend within 12 h and has good biocompatibility. Therefore, FL hydrogels have potential applications in the field of biomedicine.

Oligo(lysine)-F127 hydrogels have a temperature-responsive sol–gel transition and pH-responsive micelle morphology.

Perspectives of Molecularly Imprinted Polymer-Based Drug Delivery Systems in Cancer Therapy

Despite the considerable effort made in the past decades, multiple aspects of cancer management remain a challenge for the scientific community. The severe toxicity and poor bioavailability of conventional chemotherapeutics, and the multidrug resistance have turned the attention of researchers towards the quest of drug carriers engineered to offer an efficient, localized, temporized, and doze-controlled delivery of antitumor agents of proven clinical value. Molecular imprinting of chemotherapeutics is very appealing in the design of drug delivery systems since the specific and selective binding sites created within the polymeric matrix turn these complex structures into value-added carriers with tunable features, notably high loading capacity, and a good control of payload release. Our work aims to summarize the present state-of-the art of molecularly imprinted polymer-based drug delivery systems developed for anticancer therapy, with emphasis on the particularities of the chemotherapeutics’ release and with a critical assessment of the current challenges and future perspectives of these unique drug carriers.

Preparation of Dual-Template Epitope Imprinted Polymers for Targeted Fluorescence Imaging and Targeted Drug Delivery to Pancreatic Cancer BxPC-3 Cells

Molecularly imprinted polymers were commonly used for drug delivery. However, single-template molecularly imprinted polymers often fail to achieve both drug delivery and precise targeting. To address this issue, a dual-template molecularly imprinted polymer nanoparticle used for targeted diagnosis and drug delivery for pancreatic cancer BxPC-3 cells (FH-MIPNPs) was prepared. In the FH-MIPNPs, the 71-80 peptide of human fibroblast growth-factor-inducible 14 modified with glucose (Glu-FH) and bleomycin (BLM) were used as templates simultaneously, so that the FH-MIPNPs could load BLM and bind to the BxPC-3 cells, which overexpress human fibroblast growth-factor-inducible 14 (FN14). Targeted imaging experiments in vitro show that the FH-MIPNPs could specifically target BxPC-3 cells and that there is no targeting effect on cells without expression of FN14. In vivo antitumor experiment results demonstrated that the FH-MIPNP-loaded BLM (FH-MIPNPs/BLM) could inhibit the growth of xenografts tumor of BxPC-3 (tumor volume increased to 1.05×), which shows that FH-MIPNPs/BLM had obvious targeted therapeutic effect compared to the other three control groups of BLM, FH-NIPNPs/BLM, and physiological saline (tumor volume increased to 1.5×, 1.6×, and 2.4×, respectively). What is more, FH-MIPNPs have low biotoxicity through toxicity experiments in vitro and in vivo, which is favorable toward making molecularly imprinted polymers an effective platform for tumor-targeted imaging and therapy.

Semiconductor nanocrystal-polymer hybrid nanomaterials and their application in molecular imprinting

Quantum dots (QDs) are attractive semiconductor fluorescent nanomaterials with remarkable optical and electrical properties. The broad absorption spectra and high stability of QD transducers are advantageous for sensing and bioimaging. Molecular imprinting is a technique for manufacturing synthetic polymeric materials with a high recognition ability towards a target analyte. The high selectivity of the molecularly imprinted polymers (MIPs) is a result of the fabrication process based on the template-tailored polymerization of functional monomers. The three-dimensional cavities formed in the polymer network can serve as the recognition elements of sensors because of their specificity and stability. Appending specific molecularly imprinted layers to QDs is a promising strategy to enhance the stability, sensitivity, and selective fluorescence response of the resulting sensors. By merging the benefits of MIPs and QDs, inventive optical sensors are constructed. In this review, the recent synthetic strategies used for the fabrication of QD nanocrystals emphasizing various approaches to effective functionalization in aqueous environments are discussed followed by a detailed presentation of current advances in QD conjugated MIPs (MIP-QDs). Frontiers in manufacturing of specific imprinted layers of these nanomaterials are presented and factors affecting the specific behaviour of an MIP shell are identified. Finally, current limitations of MIP-QDs are defined and prospects are outlined to amplify the capability of MIP-QDs in future sensing.

Progress in Molecularly Imprinted Polymers for Biomedical Applications

Background:

Molecularly Imprinted Polymers (MIPs), a type of biomimetic materials have attracted considerable interest owing to their cost-effectiveness, good physiochemical stability, favorable specificity and selectivity for target analytes, and long shelf life. These materials are able to mimic natural recognition entities, including biological receptors and antibodies, providing a versatile platform to achieve the desirable functionality for various biomedical applications.

Objective:

In this review article, we introduce the most recent development of MIPs to date. We first highlight the advantages of using MIPs for a broad range of biomedical applications. We then review their various methods of synthesis along with their latest progress in biomedical applications, including biosensing, drug delivery, cell imaging and drug discovery. Lastly, the existing challenges and future perspectives of MIPs for biomedical applications are briefly discussed.

Conclusion:

We envision that MIPs may be used as potential materials for diverse biomedical applications in the near future.

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.

Hybrid Mesoporous Nanoparticles for pH-Actuated Controlled Release

Among a variety of inorganic-based nanomaterials, mesoporous silica nanoparticles (MSNs) have several attractive features for application as a delivery system, due to their high surface areas, large pore volumes, uniform and tunable pore sizes, high mechanical stability, and a great diversity of surface functionalization options. We developed novel hybrid MSNs composed of a mesoporous silica nanostructure core and a pH-responsive polymer shell. The polymer shell was prepared by RAFT polymerization of 2-(diisopropylamino)ethyl methacrylate (pKa ~6.5), using a hybrid grafting approach. The hybrid nanoparticles have diameters of ca. 100 nm at pH < 6.5 and ca. 60 nm at pH > 6.5. An excellent control of cargo release is achieved by the combined effect of electrostatic interaction of the cargo with the charged silica and the extended cationic polymer chains at low pH, and the reduction of electrostatic attraction with a simultaneous collapse of the polymer chains to a globular conformation at higher pH. The system presents a very low (almost null) release rate at acidic pH values and a large release rate at basic pH, resulting from the squeezing-out effect of the coil-to-globule transition in the polymer shell.

Molecularly Imprinted Polymer Based Sensors for Medical Applications

Sensors have been extensively used owing to multiple advantages, including exceptional sensing performance, user-friendly operation, fast response, high sensitivity and specificity, portability, and real-time analysis. In recent years, efforts in sensor realm have expanded promptly, and it has already presented a broad range of applications in the fields of medical, pharmaceutical and environmental applications, food safety, and homeland security. In particular, molecularly imprinted polymer based sensors have created a fascinating horizon for surface modification techniques by forming specific recognition cavities for template molecules in the polymeric matrix. This method ensures a broad range of versatility to imprint a variety of biomolecules with different size, three dimensional structure, physical and chemical features. In contrast to complex and time-consuming laboratory surface modification methods, molecular imprinting offers a rapid, sensitive, inexpensive, easy-to-use, and highly selective approaches for sensing, and especially for the applications of diagnosis, screening, and theranostics. Due to its physical and chemical robustness, high stability, low-cost, and reusability features, molecularly imprinted polymer based sensors have become very attractive modalities for such applications with a sensitivity of minute structural changes in the structure of biomolecules. This review aims at discussing the principle of molecular imprinting method, the integration of molecularly imprinted polymers with sensing tools, the recent advances and strategies in molecular imprinting methodologies, their applications in medical, and future outlook on this concept.