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Late stage CH functionalization is a powerful tool for modification of natural compounds. Herein we report that the rhodium-catalyzed reaction of brassinosteroids with aryloxysulfonamides proceeds regio- and stereoselectively at C15 position. The derivative obtained from 24-epibrassinolide was easily transformed to the conjugate with a BODIPY dye bearing unaffected functional groups of the native brassinosteroid.
The increasing popularity of peptides as promising molecular scaffolds for biomedical applications and as valuable biochemical probes makes new methods allowing for their modification highly desirable. We describe herein an optimized protocol based on a sequence of CuAAC click reactions and selective deprotection steps, which leads to an efficient multi-functionalization of synthetic peptides. The methodology has been successfully applied to the construction of defined heteroglycopeptides and fluorophore-quencher-containing probes for proteases. The developed chemistry thus represents an important addition to the available toolbox of methods enabling efficient postsynthetic modification of peptides. The commercial availability of numerous azide probes further greatly extends the application potential of the described methodology.
In this critical review, we outline various covalent and non-covalent approaches for the functionalization of iron oxide nanoparticles (IONPs). Tuning the surface chemistry and design of magnetic nanoparticles are described in relation to their applicability in advanced medical technologies and biotechnologies including magnetic resonance imaging (MRI) contrast agents, targeted drug delivery, magnetic separations and immobilizations of proteins, enzymes, antibodies, targeting agents and other biosubstances. We review synthetic strategies for the controlled preparation of IONPs modified with frequently used functional groups including amine, carboxyl and hydroxyl groups as well as the preparation of IONPs functionalized with other species, e.g., epoxy, thiol, alkane, azide, and alkyne groups. Three main coupling strategies for linking IONPs with active agents are presented: (i) chemical modification of amine groups on the surface of IONPs, (ii) chemical modification of bioactive substances (e.g. with fluorescent dyes), and (iii) the activation of carboxyl groups mainly for enzyme immobilization. Applications for drug delivery using click chemistry linking or biodegradable bonds are compared to non-covalent methods based on polymer modified condensed magnetic nanoclusters. Among many challenges, we highlight the specific surface engineering allowing both therapeutic and diagnostic applications (theranostics) of IONPs and magnetic/metallic hybrid nanostructures possessing a huge potential in biocatalysis, green chemistry, magnetic bioseparations and bioimaging.
Scaffolds populated with human cardiac progenitor cells (CPCs) represent a therapeutic opportunity for heart regeneration after myocardial infarction. In this work, square-grid scaffolds are prepared by melt-extrusion additive manufacturing from a polyurethane (PU), further subjected to plasma treatment for acrylic acid surface grafting/polymerization and finally grafted with laminin-1 (PU-LN1) or gelatin (PU-G) by carbodiimide chemistry. LN1 is a cardiac niche extracellular matrix component and plays a key role in heart formation during embryogenesis, while G is a low-cost cell-adhesion protein, here used as a control functionalizing molecule. X-ray photoelectron spectroscopy analysis shows nitrogen percentage increase after functionalization. O1s and C1s core-level spectra and static contact angle measurements show changes associated with successful functionalization. ELISA assay confirms LN1 surface grafting. PU-G and PU-LN1 scaffolds both improve CPC adhesion, but LN1 functionalization is superior in promoting proliferation, protection from apoptosis and expression of differentiation markers for cardiomyocytes, endothelial and smooth muscle cells. PU-LN1 and PU scaffolds are biodegraded into non-cytotoxic residues. Scaffolds subcutaneously implanted in mice evoke weak inflammation and integrate with the host tissue, evidencing a significant blood vessel density around the scaffolds. PU-LN1 scaffolds show their superiority in driving CPC behavior, evidencing their promising role in myocardial regenerative medicine.
- MeSH
- biomimetika MeSH
- kmenové buňky cytologie fyziologie MeSH
- kultivované buňky MeSH
- lidé středního věku MeSH
- lidé MeSH
- myokard MeSH
- myši MeSH
- polyurethany chemie MeSH
- řízená tkáňová regenerace metody MeSH
- srdeční síně cytologie MeSH
- testování materiálů MeSH
- tkáňové inženýrství * MeSH
- tkáňové podpůrné struktury * MeSH
- transplantace kmenových buněk * MeSH
- zvířata MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Specifically designed and functionalized nanoparticles hold great promise for biomedical applications. Yet, the applicability of nanoparticles is critically predetermined by their surface functionalization and biodegradability. Here we demonstrate that amino-functionalized polystyrene nanoparticles (PS-NH2), but not amino- or hydroxyl-functionalized silica particles, trigger cell death in hepatocellular carcinoma Huh7 cells. Importantly, biodegradability of nanoparticles plays a crucial role in regulation of essential cellular processes. Thus, biodegradable silica nanoparticles having the same shape, size and surface functionalization showed opposite cellular effects in comparison with similar polystyrene nanoparticles. At the molecular level, PS-NH2 obstruct and amino-functionalized silica nanoparticles (Si-NH2) activate the mTOR signalling in Huh7 and HepG2 cells. PS-NH2 induced time-dependent lysosomal destabilization associated with damage of the mitochondrial membrane. Solely in PS-NH2-treated cells, permeabilization of lysosomes preceded cell death. Contrary, Si-NH2 nanoparticles enhanced proliferation of HuH7 and HepG2 cells. Our findings demonstrate complex cellular responses to functionalized nanoparticles and suggest that nanoparticles can be used to control activation of mTOR signaling with subsequent influence on proliferation and viability of HuH7 cells. The data provide fundamental knowledge which could help in developing safe and efficient nano-therapeutics.
- MeSH
- adsorpce MeSH
- aminy chemie MeSH
- hepatocelulární karcinom metabolismus patologie MeSH
- konformace proteinů MeSH
- lyzozomy metabolismus MeSH
- nádorové buněčné linie MeSH
- nádory jater metabolismus patologie MeSH
- nanočástice chemie MeSH
- oxid křemičitý chemie MeSH
- permeabilita MeSH
- polystyreny chemie MeSH
- povrchové vlastnosti MeSH
- proliferace buněk MeSH
- ribonukleasy metabolismus MeSH
- sérový albumin hovězí metabolismus MeSH
- signální transdukce * MeSH
- skot MeSH
- TOR serin-threoninkinasy metabolismus MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Composite materials based on a titanium support and a thin, alginate hydrogel could be used in bone tissue engineering as a scaffold material that provides biologically active molecules. The main objective of this contribution is to characterize the activation and the functionalization of titanium surfaces by the covalent immobilization of anchoring layers of self-assembled bisphosphonate neridronate monolayers and polymer films of 3-aminopropyltriethoxysilane and biomimetic poly(dopamine). These were further used to bind a bio-functional alginate coating. The success of the titanium surface activation, anchoring layer formation and alginate immobilization, as well as the stability upon immersion under physiological-like conditions, are demonstrated by different surface sensitive techniques such as spectroscopic ellipsometry, infrared reflection-absorption spectroscopy and X-ray photoelectron spectroscopy. The changes in morphology and the established continuity of the layers are examined by scanning electron microscopy, surface profilometry and atomic force microscopy. The changes in hydrophilicity after each modification step are further examined by contact angle goniometry.
- Publikační typ
- časopisecké články MeSH
Nearly monodispersed superparamagnetic maghemite nanoparticles (15-20nm) were prepared by a one-step thermal decomposition of iron(II) acetate in air at 400 degrees C. The presented synthetic route is simple, cost effective and allows to prepare the high-quality superparamagnetic particles in a large scale. The as-prepared particles were exploited for the development of magnetic nanocomposites with the possible applicability in medicine and biochemistry. For the purposes of the MRI diagnostics, the maghemite particles were simply dispersed in the bentonite matrix. The resulting nanocomposite represents very effective and cheap oral negative contrast agent for MRI of the gastrointestinal tract and reveals excellent contrast properties, fully comparable with those obtained for commercial contrast material. The results of the clinical research of this maghemite-bentonite contrast agent for imaging of the small bowel are discussed. For biochemical applications, the primary functionalization of the prepared maghemite nanoparticles with chitosan was performed. In this way, a highly efficient magnetic carrier for protein immobilization was obtained as demonstrated by conjugating thermostable raffinose-modified trypsin (RMT) using glutaraldehyde. The covalent conjugation resulted in a further increase in trypsin thermostability (T(50)=61 degrees C) and elimination of its autolysis. Consequently, the immobilization of RMT allowed fast in-solution digestion of proteins and their identification by MALDI-TOF mass spectrometry.
- MeSH
- difrakce rentgenového záření MeSH
- enzymy imobilizované MeSH
- financování organizované MeSH
- gastrointestinální trakt patologie MeSH
- kontrastní látky MeSH
- magnetická rezonanční tomografie MeSH
- mikroskopie elektronová rastrovací MeSH
- transmisní elektronová mikroskopie MeSH
- trypsin MeSH
- železité sloučeniny MeSH
The non-specific binding of non-target species to functionalized surfaces of biosensors continues to be challenge for biosensing in real-world media. Three different low-fouling and functionalizable surface platforms were employed to study the effect of functionalization on fouling resistance from several types of undiluted media including blood plasma and food media. The surface platforms investigated in this work included two polymer brushes: hydroxy-functional poly(2-hydroxyethyl methacrylate) (pHEMA) and carboxy-functional poly(carboxybetaine acrylamide) (pCBAA), and a standard OEG-based carboxy-functional alkanethiolate self-assembled monolayer (AT-SAM). The wet and dry polymer brushes were analyzed by AFM, ellipsometry, FT-IRRAS, and surface plasmon resonance (SPR). The surfaces were functionalized by the covalent attachment of antibodies, streptavidin, and oligonucleotides and the binding and biorecognition characteristics of the coatings were compared. We found that functionalization did not substantially affect the ultra-low fouling properties of pCBAA (plasma fouling of ~20 ng/cm(2)), a finding in contrast with pHEMA that completely lost its resistance to fouling after the activation of hydroxyl groups. Blocking a functionalized AT-SAM covalently with BSA decreased fouling down to the level comparable to unblocked pCBAA. However, the biorecognition capability of blocked functionalized AT-SAM was poor in comparison with functionalized pCBAA. Limits of detection of Escherichia coli O157:H7 in undiluted milk were determined to be 6×10(4), 8×10(5), and 6×10(5) cells/ml for pCBAA, pHEMA, and AT-SAM-blocked, respectively. Effect of analyte size on biorecognition activity of functionalized coatings was investigated and it was shown that the best performance in terms of overall fouling resistance and biorecognition capability is provided by pCBAA.
- MeSH
- adsorpce MeSH
- akrylamidy chemie MeSH
- Escherichia coli izolace a purifikace MeSH
- limita detekce MeSH
- mléko mikrobiologie MeSH
- polyhydroxyethylmethakrylát chemie MeSH
- polymery chemie MeSH
- povrchová plasmonová rezonance metody MeSH
- povrchové vlastnosti MeSH
- sulfhydrylové sloučeniny chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Photon-upconversion nanoparticles (UCNP) have already been established as labels for affinity assays in analog and digital formats. Here, advanced, or smart, systems based on UCNPs coated with active shells, fluorescent dyes, and metal and semiconductor nanoparticles participating in energy transfer reactions are reviewed. In addition, switching elements can be embedded in such assemblies and provide temporal and spatial control of action, which is important for intracellular imaging and monitoring activities. Demonstration and critical comments on representative approaches demonstrating the progress in the use of such UCNPs in bioanalytical assays, imaging, and monitoring of target molecules in cells are reported, including particular examples in the field of cancer theranostics.
