Biomimetic System Based on Reconstituted Macrophage Membranes for Analyzing and Selection of Higher-Affinity Ligands Specific to Mannose Receptor to Develop the Macrophage-Focused Medicines

Progress in macrophage research is crucial for numerous applications in medicine, including cancer and infectious diseases. However, the existing methods to manipulate living macrophages are labor-intense and inconvenient. Here, we show that macrophage membranes can be reconstituted after storage for months at 4 °C, with their CD206 receptor selectivity and specificity being similar to those in the living cells. Then, we have developed a mannose ligand, specific to CD206, linked with PEG as an IR spectroscopy marker to detect binding with the macrophage receptor. PEG was selected due to its unique adsorption band of the C-O-C group at IR spectra, which does not overlap with other biomolecules' spectroscopic feature. Next, competitive binding assay versus the PEG-bound ligand has enabled the selection of other higher-affinity ligands specific to CD206. Furthermore, those higher-affinity ligands were used to differentiate activated macrophages in a patient's bronchoalveolar (BAL) or nasopharyngeal (NPL) lavage. CD206- control cells (HEK293T) showed only non-specific binding. Therefore, biochips based on reconstituted macrophage membranes as well as PEG-trimannoside as an IR spectroscopic marker can be used to develop new methods facilitating macrophage research and macrophage-focused drug discovery.

Progress and prospects of polysaccharide-based nanocarriers for oral delivery of proteins/peptides

The oral route has long been recognized as the most preferred route for drug delivery as it offers high patient compliance and requires minimal expertise. Unlike small molecule drugs, the harsh environment of the gastrointestinal tract and low permeability across the intestinal epithelium make oral delivery extremely ineffective for macromolecules. Accordingly, delivery systems that are rationally constructed with suitable materials to overcome barriers to oral delivery are exceptionally promising. Among the most ideal materials are polysaccharides. Depending on the interaction between polysaccharides and proteins, the thermodynamic loading and release of proteins in the aqueous phase can be realized. Specific polysaccharides (dextran, chitosan, alginate, cellulose, etc.) endow systems with functional properties, including muco-adhesiveness, pH-responsiveness, and prevention of enzymatic degradation. Furthermore, multiple groups in polysaccharides can be modified, which gives them a variety of properties and enables them to suit specific needs. This review provides an overview of different types of polysaccharide-based nanocarriers based on different kinds of interaction forces and the influencing factors in the construction of polysaccharide-based nanocarriers. Strategies of polysaccharide-based nanocarriers to improve the bioavailability of orally administered proteins/peptides were described. Additionally, current restrictions and future trends of polysaccharide-based nanocarriers for oral delivery of proteins/peptides were also covered.

Thermoreversible Gels Based on Chitosan Copolymers as "Intelligent" Drug Delivery System with Prolonged Action for Intramuscular Injection

Thermosensitive gels based on copolymers (PEG-chitosan, chitosan-polyethylenimine, chitosan-arginine and glycol-chitosan-spermine) are presented as promising polycations for the formation of DNA polyplexes and the potential for the development of drugs with prolonged release (up to 30 days). Being in liquid form at room temperature, such compounds can be injected into muscle tissue with rapid gel formation at human body temperature. An intramuscular depot is formed with a therapeutic agent that provides a gradual release of the drug, such as an antibacterial or cytostatic. The physico-chemical parameters of the formation of polyplexes between polycationic polymers of various compositions and molecular architecture and DNA were studied via FTIR, UV-vis and fluorescence spectroscopy using the dyes rhodamine 6G (R6G) and acridine orange (AO). The competitive displacement of AO from AO-DNA complexes showed that, with a ratio of N/P = 1, most of the DNA is bound to a polycation. During the formation of polyplexes, the DNA charge is neutralized by a polycation, which is reflected in electrophoretic immobility. The cationic polymers described in this work at a concentration of 1-4% are capable of forming gels, and the thermoreversible property is most characteristic of pegylated chitosan. BSA, as a model anionic molecule, is released by half in 5 days from the Chit5-PEG5 gel; full release is achieved in 18-20 days. At the same time, in 5 days, the gel is destroyed up to 30%, and in 20 days, by 90% (release of chitosan particles). For the first time, flow cytometry was used to study DNA polyplexes, which showed the existence of fluorescent particles in a much larger number in combination with free DNA. Thus, functional stimulus-sensitive polymers are potentially applicable for the creation of prolonged therapeutic formulations for gene delivery systems, which were obtained. The revealed regularities appear to be a platform for the design of polyplexes with controllable stability, in particular, fulfilling the requirements imposed for gene delivery vehicles.

Application Prospects of FTIR Spectroscopy and CLSM to Monitor the Drugs Interaction with Bacteria Cells Localized in Macrophages for Diagnosis and Treatment Control of Respiratory Diseases

Visualization of the interaction of drugs with biological cells creates new approaches to improving the bioavailability, selectivity, and effectiveness of drugs. The use of CLSM and FTIR spectroscopy to study the interactions of antibacterial drugs with latent bacterial cells localized in macrophages create prospects to solve the problems of multidrug resistance (MDR) and severe cases. Here, the mechanism of rifampicin penetration into E. coli bacterial cells was studied by tracking the changes in the characteristic peaks of cell wall components and intracellular proteins. However, the effectiveness of the drug is determined not only by penetration, but also by efflux of the drugs molecules from the bacterial cells. Here, the efflux effect was studied and visualized using FTIR spectroscopy, as well as CLSM imaging. We have shown that because of efflux inhibition, eugenol acting as an adjuvant for rifampicin showed a significant (more than three times) increase in the antibiotic penetration and the maintenance of its intracellular concentration in E. coli (up to 72 h in a concentration of more than 2 μg/mL). In addition, optical methods have been applied to study the systems containing bacteria localized inside of macrophages (model of the latent form), where the availability of bacteria for antibiotics is reduced. Polyethylenimine grafted with cyclodextrin carrying trimannoside vector molecules was developed as a drug delivery system for macrophages. Such ligands were absorbed by CD206+ macrophages by 60-70% versus 10-15% for ligands with a non-specific galactose label. Owing to presence of ligands with trimannoside vectors, the increase in antibiotic concentration inside macrophages, and thus, its accumulation into dormant bacteria, is observed. In the future, the developed FTIR+CLSM techniques would be applicable for the diagnosis of bacterial infections and the adjustment of therapy strategies.

A Review on Recent Advances in Mannose-Functionalized Targeted Nanocarrier Delivery Systems in Cancer and Infective Therapeutics

Unmodified nanocarriers used in the chemotherapy of cancers and various infectious diseases exhibit prolonged blood circulation time, prevent enzymatic degradation and increase chemical stability of encapsulated therapeutics. However, off-target effect and lack of specificity associated with unmodified nanoparticles (NPs) limit their applications in the health care system. Mannose (Man) receptors with significant overexpression on antigen-presenting cells and macrophages are among the most admired targets for cancer and anti-infective therapeutics. Therefore, development of Man functionalized nanocarriers targeting Man receptors, for target specific drug delivery in the chemotherapy have been extensively studied. Present review expounds diverse Man-conjugated NPs with their potential for targeted drug delivery, improved biodistribution profiles and localization. Additionally, the review gives detailed account of the interactions of mannosylated NPs with various biological systems and their characterization not discussed in earlier published reports is discussed.

Mannosylated Systems for Targeted Delivery of Antibacterial Drugs to Activated Macrophages

Macrophages are a promising target for drug delivery to influence macrophage-associated processes in the body, namely due to the presence of resistant microorganisms in macrophages. In this work, a series of mannosylated carriers based on mannan, polyethylenimine (PEI) and cyclodextrin (CD) was synthesized. The molecular architecture was studied using FTIR and ¹H NMR spectroscopy. The particle size, from small 10-50 nm to large 500 nm, depending on the type of carrier, is potentially applicable for the creation of various medicinal forms: intravenous, oral and inhalation. Non-specific capture by cells with a simultaneous increase in selectivity to CD206+ macrophages was achieved. ConA was used as a model mannose receptor, binding galactosylated (CD206 non-specific) carriers with constants of the order of 10⁴ M^-1 and mannosylated conjugates of 10⁶-10⁷ M^-1. The results of such primary "ConA-screening" of ligands are in a good agreement in terms of the comparative effectiveness of the interaction of ligands with the CD206+ macrophages: non-specific (up to 10%) absorption of highly charged and small particles; weakly specific uptake of galactosylated polymers (up to 50%); and high affine capture (more than 70-80%) of the ligands with grafted trimannoside was demonstrated using the cytometry method. Double and multi-complexes of antibacterials (moxifloxacin with its adjuvants from the class of terpenoids) were proposed as enhanced forms against resistant pathogens. In vivo pharmacokinetic experiments have shown that polymeric carriers significantly improve the efficiency of the antibiotic: the half-life of moxifloxacin is increased by 2-3 times in conjugate-loaded forms, bio-distribution to the lungs in the first hours after administration of the drug is noticeably greater, and, after 4 h of observation, free moxifloxacin was practically removed from the lungs of rats. Although, in polymer systems, its content is significant-1.2 µg/g. Moreover, the importance of the covalent crosslinking carrier with mannose label was demonstrated. Thus, this paper describes experimental, scientifically based methods of targeted drug delivery to macrophages to create enhanced medicinal forms.

Mannosylated Polymeric Ligands for Targeted Delivery of Antibacterials and Their Adjuvants to Macrophages for the Enhancement of the Drug Efficiency

Bacterial infections and especially resistant strains of pathogens localized in macrophages and granulomas are intractable diseases that pose a threat to millions of people. In this paper, the theoretical and experimental foundations for solving this problem are proposed due to two key aspects. The first is the use of a three-component polymer system for delivering fluoroquinolones to macrophages due to high-affinity interaction with mannose receptors (CD206). Cytometry assay determined that 95.5% macrophage-like cells were FITC-positive after adding high-affine to CD206 trimannoside conjugate HPCD-PEI1.8-triMan, and 61.7% were FITC-positive after adding medium-affine ligand with linear mannose label HPCD-PEI1.8-Man. The second aspect is the use of adjuvants, which are synergists for antibiotics. Using FTIR and NMR spectroscopy, it was shown that molecular containers, namely mannosylated polyethyleneimines (PEIs) and cyclodextrins (CDs), load moxifloxacin (MF) with dissociation constants of the order of 10⁻⁴–10⁻⁶ M; moreover, due to prolonged release and adsorption on the cell membrane, they enhance the effect of MF. Using CLSM, it was shown that eugenol (EG) increases the penetration of doxorubicin (Dox) into cells by an order of magnitude due to the creation of defects in the bacterial wall and the inhibition of efflux proteins. Fluorescence spectroscopy showed that 0.5% EG penetrates into bacteria and inhibits efflux proteins, which makes it possible to increase the maximum concentration of the antibiotic by 60% and maintain it for several hours until the pathogens are completely neutralized. Regulation of efflux is a possible way to overcome multiple drug resistance of both pathogens and cancer cells.

Organic/Inorganic Self-Assembled Hybrid Nano-Architectures for Cancer Therapy Applications

Since the conceptualization of nanomedicine, numerous nanostructure-mediated drug formulations have progressed into clinical trials for treating cancer. However, recent clinical trial results indicate such kind of drug formulations has a limited improvement on the antitumor efficacy. This is due to the biological barriers associated with those formulations, for example, circulation stability, extravasation efficiency in tumor, tumor penetration ability, and developed multi-drug resistance. When employing for nanomedicine formulations, pristine organic-based and inorganic-based nanostructures have their own limitations. Accordingly, organic/inorganic (O/I) hybrids have been developed to integrate the merits of both, and to minimize their intrinsic drawbacks. In this context, the recent development in O/I hybrids resulting from a self-assembly strategy will be introduced. Through such a strategy, organic and inorganic building blocks can be self-assembled via either chemical covalent bonds or physical interactions. Based on the self-assemble procedure, the hybridization of four organic building blocks including liposomes, micelles, dendrimers, and polymeric nanocapsules with five functional inorganic nanoparticles comprising gold nanostructures, magnetic nanoparticles, carbon-based materials, quantum dots, and silica nanoparticles will be highlighted. The recent progress of these O/I hybrids in advanced modalities for combating cancer, such as, therapeutic agent delivery, photothermal therapy, photodynamic therapy, and immunotherapy will be systematically reviewed.

Nanoemulsions for synthesis of biomedical nanocarriers

Nanoemulsions are kinetically stabilized emulsions with droplet sizes in the nanometer scale. These nanodroplets are able to confine spaces in which reactions of polymerization or precipitation can take place, leading to the formation of particles and capsules that can act as nanocarriers for biomedical applications. This review discusses the different possibilities of using nanoemulsions for preparing biomedical nanocarriers. According to the chemical nature, nanocarriers prepared in nanoemulsions are classified in polymeric, inorganic, or hybrid. The main synthetic strategies for each type are revised, including miniemulsion polymerization, nanoemulsion-solvent evaporation, spontaneous emulsification, sol-gel processes, and combination of different techniques to form multicomponent materials.

Polyurethane-functionalized starch nanocrystals as anti-tuberculosis drug carrier

Studies related to loading ability and delivery of clinically used first-line anti-tuberculosis drugs (ATDs) such as isoniazid, rifampicin, pyrazinamide and streptomycin on the surface of starch-derived bulk and nanopolyurethanes (SBPUs and SNPUs) as drug delivery systems (DDS) have been focused to minimise or remove the drug-associated adverse effects. The efficiencies of nanopolyurethanes obtained from the differently substituted cyclic aliphatic and aromatic isocyanates have been studied for drug loading and release purposes. Different advanced instrumental techniques analysed the structural and morphological properties, thermal stability and crystallinity of the starch nanopolyurethans. Average particle sizes ranging from 27.35–42.38 nm to 126.89–218.60 nm for starch nanopolyurethans, SNPU3i and SNPU4i, respectively, were determined by high-resolution transmission electron microscopy. Similarly, the loading efficiency of ATDs to the surfaces of SNPUs and SBPUs was observed in the range of 60–97% while ATDs-loaded SNPUs showed a sustainable release profile for all ATDs except for streptomycin. However, most SBPUs provided burst-release for all the above-mentioned ATDs in pH-dependent studies. The anti-tuberculosis assay against the Mycobacterium tuberculosis H37Rv strain revealed that streptomycin-loaded SNPU4i and isoniazid-loaded SNPU7i are approximately 42 and 7 times more active than the native streptomycin and isoniazid, respectively.

Hydroxyethyl starch based smart nanomedicine

In the past decades, the vigorous development of nanomedicine has opened up a new world for drug delivery. Hydroxyethyl starch (HES), a clinical plasma volume expander which has been widely used for years, is playing an attracting role as drug carriers. Compared with all other polysaccharides, HES has proven its unique characteristics for drug delivery platforms, including good manufacture practice, biodegradability, biocompatibility, abundant groups for chemical modification, excellent water solubility, and tailorability. In this review, an overview of various types of HES based drug delivery systems is provided, including HES-drug conjugates, HES-based nano-assemblies, HES-based nanocapsules, and HES-based hydrogels. In addition, the current challenges and future opportunities for design and application of HES based drug delivery systems are also discussed. The available studies show that HES based drug delivery systems has significant potential for clinical translation.

Modulation of Macrophages M1/M2 Polarization Using Carbohydrate-Functionalized Polymeric Nanoparticles

Exploiting surface endocytosis receptors using carbohydrate-conjugated nanocarriers brings outstanding approaches to an efficient delivery towards a specific target. Macrophages are cells of innate immunity found throughout the body. Plasticity of macrophages is evidenced by alterations in phenotypic polarization in response to stimuli, and is associated with changes in effector molecules, receptor expression, and cytokine profile. M1-polarized macrophages are involved in pro-inflammatory responses while M2 macrophages are capable of anti-inflammatory response and tissue repair. Modulation of macrophages’ activation state is an effective approach for several disease therapies, mediated by carbohydrate-coated nanocarriers. In this review, polymeric nanocarriers targeting macrophages are described in terms of production methods and conjugation strategies, highlighting the role of mannose receptor in the polarization of macrophages, and targeting approaches for infectious diseases, cancer immunotherapy, and prevention. Translation of this nanomedicine approach still requires further elucidation of the interaction mechanism between nanocarriers and macrophages towards clinical applications.

Multivalency Beats Complexity: A Study on the Cell Uptake of Carbohydrate Functionalized Nanocarriers to Dendritic Cells

Herein, we report the synthesis of carbohydrate and glycodendron structures for dendritic cell targeting, which were subsequently bound to hydroxyethyl starch (HES) nanocapsules prepared by the inverse miniemulsion technique. The uptake of the carbohydrate-functionalized HES nanocapsules into immature human dendritic cells (hDCs) revealed a strong dependence on the used carbohydrate. A multivalent mannose-terminated dendron was found to be far superior in uptake compared to the structurally more complex oligosaccharides used.

Crosslinked polymer nanocapsules for therapeutic, diagnostic, and theranostic applications

Crosslinked polymer nanocapsules (CPNCs) are hollowed nanoparticles with network-like polymeric shells stabilized by primary bonds. CPNCs have drawn broad and significant interests as nanocarriers for biomedical applications in recent years. As compared with conventional polymeric nanoparticles systems without cavity and/or crosslinking architectures, CPNCs possess significant biomedical relevant advantages, including (a) superior structural stability against environmental conditions, (b) high loading capacity and ability for region-specific loading of multiple cargos, (c) tuneable cargo release rate via crosslinking density, and (d) high specific surface area to facilitate surface adsorption, modification, and interactions. With appropriate base polymers and crosslinkages, CPNCs can be biocompatible and biodegradable. While CPNC-based biomedical nanoplatforms can possess relatively stable physicochemical properties owing to their crosslinked architectures, various biomedically relevant stimuli-responsivities can be incorporated with them through specific structural designs. CPNCs have been studied for the delivery of small molecule drugs, genes, proteins, and other therapeutic agents. They have also been investigated as diagnostic platforms for magnetic resonance imaging, ultrasound imaging, and optical imaging. Moreover, CPNCs have been utilized to carry both therapeutics and bioimaging agents for theranostic applications. This article reviews the therapeutic, diagnostic and theranostic applications of CPNCs, as well as the preparation of these CPNCs, reported in the past decade. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Implantable Materials and Surgical Technologies > Nanomaterials and Implants Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Glycans in nanomedicine, impact and perspectives

Glycans have been selected by nature for both structural and 'recognition' purposes. Taking inspiration from nature, nanomedicine exploits glycans not only as structural constituents of nanoparticles and nanostructured biomaterials but also as selective interactors of such glyco-nanotools. Surface glycosylation of nanoparticles finds application in targeting specific cells, whereas recent findings give evidence that the glycan content of cell microenvironment is able to induce the cell fate. This review will highlight the role of glycans in nanomedicine, schematizing the different uses and roles in drug-delivery systems and in biomaterials for regenerative medicine.

Sonochemical fabrication of reduction-responsive magnetic starch-based microcapsules

In this work, a novel, biocompatible, non-immunogenic and reductive-responsive magnetic starch-based microcapsules (RMSMCs) were designed and fabricated successfully via a facile sonochemical method for targeted delivery and triggered release of hydrophobic drugs. TEM image indicated that oleic acid (OA) modified Fe₃O₄ nanoparticles (OA-Fe₃O₄ NPs) were encapsulated into RMSMCs. The obtained RMSMCs were endowed with magnetism for drug targeted delivery because that the superparamagnetic OA-Fe₃O₄ NPs were encapsulated into RMSMCs. Moreover, Coumarin 6 (C6), a green fluorescent dye, was used as a model hydrophobic drug and loaded into RMSMCs. As drug carriers, the obtained spherical RMSMCs with the average size of 2 μm presented excellent reductive-responsive release ability for hydrophobic drugs. Accordingly, the obtained RMSMCs would be promising carriers for targeted delivery and triggered release of hydrophobic drugs in biomedical applications.

Morphology-dependent pH-responsive release of hydrophilic payloads using biodegradable nanocarriers

The development of functional nanocarriers with stimuli-responsive properties has advanced tremendously to serve biomedical applications such as drug delivery and regenerative medicine. However, the development of biodegradable nanocarriers that can be loaded with hydrophilic compounds and ensure its controlled release in response to changes in the surrounding environment still remains very challenging. Herein, we achieved such demands via the preparation of aqueous core nanocapsules using a base-catalyzed interfacial reaction employing a diisocyanate monomer and functional monomers/polymers containing thiol and hydroxyl functionalities at the droplet interface. pH-responsive poly(thiourethane–urethane) nanocarriers with ester linkages were synthesized by incorporating polycaprolactone diol, which is susceptible to hydrolytic degradation via ester linkages, as a functional monomer in the reaction formulation. We could demonstrate that by systematically varying the number of biodegradable segments, the morphology of the nanocarriers can be tuned without imparting the efficient encapsulation of hydrophilic payload (>85% encapsulation efficiency) and its transfer from organic to aqueous phase. The developed nanocarriers allow for a fast release of hydrophilic payload that depends on pH, the number of biodegradable segments and nanocarrier morphology. Succinctly put, this study provides important information to develop pH-responsive nanocarriers with tunable morphology, using interfacial reactions in the inverse miniemulsion process, by controlling the number of degradable segments to adjust the release profile depending on the type of application envisaged.

The morphology and release properties of aqueous core nanocapsules for the pH-responsive release of hydrophilic payload was investigated by systematically varying the number of biodegradable segments.

Chloroquine-Modified Hydroxyethyl Starch as a Polymeric Drug for Cancer Therapy

Hydroxyethyl starch (HES) is a clinically used polysaccharide colloidal plasma volume expander. The goal of this study was to synthesize HES modified with hydroxychloroquine (HCQ) as a novel polymeric drug with the ability to inhibit the invasive character of pancreatic cancer (PC) cells. HES was conjugated with HCQ using a simple carbonyldiimidazole coupling to prepare Chloroquine-modified HES (CQ-HES). CQ-HES with various degrees of HCQ substitution were synthesized and characterized. Atomic force microscopy was used to demonstrate a pH-dependent assembly of CQ-HES into well-defined nanoparticles. In vitro studies in multiple PC cell lines showed CQ-HES to have a similar toxicity profile as HCQ. Confocal microscopy revealed the propensity of CQ-HES to localize to lysosomes and mechanistic studies confirmed the ability of CQ-HES to inhibit autophagy in PC cells. Further studies demonstrated a greatly enhanced ability of CQ-HES to inhibit the migration and invasion of PC cells when compared with HCQ. The enhanced inhibitory actions of CQ-HES compared to HCQ appeared to arise in part from the increased inhibition of ERK and Akt phosphorylation. We found no significant HCQ release from CQ-HES, which confirmed that the observed activity was due to the action of CQ-HES as a polymeric drug. Due to its promising ability to block cancer cell invasion and the ability to form nanoparticles, CQ-HES has the potential as a drug delivery platform suitable for future development with chemotherapeutics to establish novel antimetastatic treatments.

Drug Delivery Systems Based on Hydroxyethyl Starch

The advantageous biological properties of hydroxyethyl starch (HES) triggered research interest toward the design and synthesis of drug delivery systems (DDSs) based on this polysaccharide. Convenient reaction schemes, including one-step reactions, led to the synthesis of HES conjugates with selected anticancer molecules or therapeutic proteins. Nanocapsules and hydrogels based on HES were also prepared and studied as prospective drug delivery systems. Formulations originating from these drug conjugates and also from nanocapsules and hydrogels loaded with drugs were characterized, highlighting the extension of their half-life in plasma, which is a critical property as far as their efficacy is concerned. Results obtained in vitro and in vivo proved promising, justifying the undertaking of additional experiments with such systems, including their multifunctionalization. The promising formulations that are discussed in this Topical Review is expected to further increase interest in applying HES for molecular constructing novel DDSs with enhanced efficacy, which may, in the future, find clinical applications.

Controlling the Stealth Effect of Nanocarriers through Understanding the Protein Corona

The past decade has seen a significant increase in interest in the use of polymeric nanocarriers in medical applications. In particular, when used as drug vectors in targeted delivery, nanocarriers could overcome many obstacles for drug therapy. Nevertheless, their application is still impeded by the complex composition of the blood proteins covering the particle surface, termed the protein corona. The protein corona complicates any prediction of cell interactions, biodistribution, and toxicity. In particular, the unspecific uptake of nanocarriers is a major obstacle in clinical studies. This Minireview provides an overview of what we currently know about the characteristics of the protein corona of nanocarriers, with a focus on surface functionalization that reduces unspecific uptake (the stealth effect). The ongoing improvement of nanocarriers to allow them to meet all the requirements necessary for successful application, including targeted delivery and stealth, are further discussed.

Quantification of plant cell wall monosaccharides by reversed-phase liquid chromatography with 2-aminobenzamide pre-column derivatization and a non-toxic reducing reagent 2-picoline borane

In this report, we described a sensitive method for quantifying plant cell wall monosaccharides using chemical derivatization, reversed-phase high performance liquid chromatography separation with ultraviolet detection (HPLC-UV). Monosaccharides were derivatized with 2-aminobenzamide (2-AB) by reductive amination to increase the hydrophobicity and detected by ultraviolet absorption for HPLC-UV analysis. A non-toxic reductant, 2-picoline borane was utilized to replace the traditionally used sodium cyanoborohydride (NaCNBH3) to avoid the formation of toxic by-products. Experimental conditions were optimized using glucose as a model system to achieve a high reaction yield of 99%. Under the optimized conditions, we demonstrated that the derivatization yields of several saccharides with 2-AB using 2-picoline borane were all slightly higher than those observed using NaCNBH3. In plants, cell wall monosaccharides consist of arabinose, fucose, galactose, galacturonic acid, glucose, glucuronic acid, mannose, rhamnose, and xylose. Using our method, we successfully quantified these monosaccharides from Arabidopsis cell wall by HPLC-UV, and we obtained a good linearity at a wide dynamic range over five orders (1pmol through 10nmol of injection amount), a detection limit of ∼0.1pmole, and a high precision and accuracy.

Biocompatible Glycopolymer Nanocapsules via Inverse Miniemulsion Periphery RAFT Polymerization for the Delivery of Gemcitabine

Encapsulation of hydrophilic cancer drugs in polymeric nanocapsules was achieved in a one-pot process via the inverse miniemulsion periphery RAFT polymerization (IMEPP) approach. The chosen guest molecule was gemcitabine hydrochloride, which is used as the first-line treatment of pancreatic cancer. The resulting nanocapsules were confirmed to be ∼200 nm, with excellent encapsulation (∼96%) and loading (∼12%) efficiency. Postpolymerization reaction was successfully conducted to create glyocopolymer nanocapsules without any impact on the loads as well as the nanocapsules size or morphology. The loaded nanocapsules were specifically designed to be responsive in a reductive environment. This was confirmed by the successful disintegration of the nanocapsules in the presence of glutathione. The gemcitabine-loaded nanocapsules were tested in vitro against pancreatic cancer cells (AsPC-1), with the results showing an enhancement in the cytotoxicity by two fold due to selective accumulation and release of the nanocapsules within the cells. The results demonstrated the versatility of IMEPP as a tool to synthesize functionalized, loaded-polymeric nanocapsules suitable for drug-delivery application.

Synthesis and evaluation of glyco-coated liposomes as drug carriers for active targeting in drug delivery systems

Novel sugar-conjugated cholesterols, β-Gal-, α-Man-, β-Man-, α-Fuc-, and β-Man-6P-S-β-Ala-Chol, were synthesized and incorporated into liposomes. In vitro experiments using the glyco-coated liposomes showed that the glyco-coated liposomes are efficiently taken up by cells expressing carbohydrate-binding receptors selectively. Glyco-coated liposomes are promising candidates for drug delivery vehicles.

Tailor-made nanocontainers for combined magnetic-field-induced release and MRI

The synthesis of a novel nanocapsule-based carrier system is described, possessing a triggered release in remote-controlled fashion upon application of an external magnetic field in combination with the possibility to use the capsules as contrast agents for magnetic resonance imaging (MRI). Therefore, polymeric nanocontainers containing a high amount of superparamagnetic MnFe2 O4 nanoparticles and a thermo-degradable shell are fabricated via a miniemulsion route. The process allows the facile encapsulation of hydrophilic compounds, as demonstrated for a model dye. Release of the encapsulated dye is achieved upon application of an external alternating magnetic field. While the magnetic nanoparticles here act as heat generators to stimulate the decomposition of the shell and subsequently a release of the payload, they additionally enable the use of the nanocapsules as imaging agents for MRI. Due to the encapsulated magnetic nanoparticles, the nanocapsules possess high r2 relaxivity values of 96-120 Hz mmol(-1) , which makes them suitable for MRI. In toxicity experiments, the nanocapsules show no cell toxicity up to fairly high concentrations (600 µg mL(-1) ). Due to their dual-functionality, the nanocapsules possess high potential as nanocarriers with combined magnetic-field-induced release capability and as contrast agents for MRI.