A nanoassembled drug delivery system for anticancer treatment, formed by the host–guest interactions between paclitaxel (PTX) and β‐cyclodextrin (β‐CD) modified poly(acrylic acid) (PCDAA), is successfully prepared. After such design, the aqueous solubility of PTX is greatly increased from 0.34 to 36.02 μg mL?1, and the obtained PCDAA‐PTX nanoparticles (PCDAA‐PTX NPs) exhibit a sustained PTX release behavior in vitro. In vitro cytotoxicity finds that PCDAA‐PTX NPs can accumulate significantly in tumor cells and remain the pharmacological activity of PTX. The in vivo real‐time biodistribution of PCDAA‐PTX NPs is investigated using near‐infrared fluorescence imaging, indicating that the PCDAA‐PTX NPs can effectively target to the tumor site by the enhanced permeability and retention effect in H22 tumor‐bearing mice. Through in vivo antitumor examination, PCDAA‐PTX NPs exhibit superior efficacy in impeding the tumor growth compared to the commercially available Taxol®.
Multivalent aptamer–siRNA conjugates containing multiple mucin‐1 aptamers and BCL2‐specific siRNA are synthesized, and doxorubicin, an anthracycline anticancer drug, is loaded into these conjugates through intercalation with nucleic acids. These doxorubicin‐incorporated multivalent aptamer–siRNA conjugates are transfected to mucin‐1 overexpressing MCF‐7 breast cancer cells and their multidrug‐resistant cell lines. Doxorubicin‐incorporated multivalent aptamer–siRNA conjugates exert promising anticancer effects, such as activation of caspase‐3/7 and decrease of cell viability, on multidrug‐resistant cancer cells because of their high intracellular uptake efficiency. Thus, this delivery system is an efficient tool for combination oncotherapy with chemotherapeutics and nucleic acid drugs to overcome multidrug resistance.
The synthesis and formulation of organic semiconductors for the emerging technology of organic electronics requires the use of preparative methods and solvents being environment friendly. Today most of the active layer materials for the organic photovoltaic devices and modules are using chlorinated solvents, which are toxic and hazardous. In this work, the synthesis of poly[N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4,7‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole] (PCDTBT) in propan‐1‐ol is presented as the dispersant continuous phase in the presence of poly(vinylpyrrolidone) used as stabilizer. Suzuki–Miyaura polycondensation of 9‐(9‐heptadecanyl)‐9H‐carbazole‐2,7‐diboronic acid bis(pinacol) ester and 4,7‐bis(2‐bromo‐5‐thienyl)‐2,1,3‐benzothiadiazole in alcohol dispersion yields colloidally stable nanoparticles of PCDTBT with particles size of 330–1300 nm, depending on the stabilizer concentration. Other reaction parameters are also discussed such as the amount of base or Pd catalyst.
Aggregation‐caused quenching (ACQ) is a general phenomenon that is faced by traditional fluorescent polymers. Aggregation‐induced emission (AIE) is exactly opposite to ACQ. AIE molecules are almost nonemissive in their molecularly dissolved state, but they can be induced to show high fluorescence in the aggregated or solid state. Incorporation of AIE phenomenon into polymer design has yielded various polymers with AIE characteristics. In this review, the recent progress of AIE polymers for biological applications is summarized.
A gold standard for esophagus reconstruction is not still available. The present work aims to design a polymer patch combining synthetic polylactide‐co‐polycaprolacton and chitosan biopolymers, tailoring patch properties to esophageal tissue characteristics by a temperature‐induced precipitation method, to get multilayered patches (1L, 2L, and 3L). Characterization shows stable multilayered patches (1L and 2L) by selection of copolymer type, and their M w. In vitro investigation of the functional patch properties in simulated physiologic and pathologic conditions demonstrates that the chitosan layer (patch 3L) decreases patch stability and cell adhesion, while improves cell proliferation. Patches 2L and 3L comply with physiological esophageal pressure (3–5 kPa) and elongation (20%).
There is an urgent need for antitumor bioactive agents with minimal or no side effects over normal adjacent cells. Fucoidan is a marine‐origin polymer with known antitumor activity. However, there are still some concerns about its application due to the inconsistent experimental results, specifically its toxicity over normal cells and the mechanism behind its action. Herein, three fucoidan extracts (FEs) have been tested over normal and breast cancer cell lines. From cytotoxicity results, only one of the extracts shows selective antitumor behavior (at 0.2 mg mL−1), despite similarities in sulfation degree and carbohydrates composition. Although the three FEs present different molecular weights, depolymerization of selected samples discarded M w as the key factor in the antitumor activity. Significant differences in sulfates position and branching are observed, presenting FE 2 the higher branching degree. Based on all these experimental data, it is believed that these last two properties are the ones that influence the cytotoxic effects of fucoidan extracts.
Cell sorting is important for cell biology and regenerative medicine. A visible light‐responsive cell scaffold is produced using gold nanoparticles and collagen gel. Various kinds of cells are cultured on the visible light‐responsive cell scaffold, and the target cells are selectively detached by photoirradiation without any cytotoxicity. This is a new image‐guided cell sorting system.
Well‐defined poly(ethylene glycol)‐b‐allyl functional polylactide‐b‐polylactides (PEG‐APLA‐PLAs) are synthesized through sequential ring‐opening polymerization. PEG‐APLA‐PLAs that have amphiphilic properties and reactive allyl side chains on their intermediate blocks are successfully transferred to core–shell interface cross‐linked micelles (ICMs) by micellization and UV‐initiated irradiation. ICMs have demonstrated enhanced colloidal stability in physiological‐mimicking media. Hydrophobic molecules such as Nile Red or doxorubicin (Dox) are readily loaded into ICMs; the resulting drug‐ICM formulations possess slow and sustained drug release profiles under physiological‐mimicking conditions. ICMs exhibit negligible cytotoxicity in human uterine sarcoma cancer cells by using biodegradable aliphatic polyester as the hydrophobic segments. Relative to free Dox, Dox‐loaded ICMs show a reduced cytotoxicity due to the late intracellular release of Dox from ICMs. Overall, ICMs represent a new type of biodegradable cross‐linked micelle and can be employed as a promising platform for delivering a broad variety of hydrophobic drugs.
Highly efficient functionalization and cross‐linking of polypeptides is achieved via tyrosine‐triazolinedione (TAD) conjugation chemistry. The feasibility of the reaction is demonstrated by the reaction of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) with tyrosine containing block copolymer poly(ethylene glycol)‐Tyr4 as well as a statistical copolymer of tyrosine and lysine (poly(Lys40‐st‐Tyr10)) prepared form N‐carboxyanhydride polymerization. Selective reaction of PTAD with the tyrosine units is obtained and verified by size exclusion chromatography and NMR spectroscopy. Moreover, two monofunctional and two difunctional TAD molecules are synthesized. It is found that their stability in the aqueous reaction media significantly varied. Under optimized reaction conditions selective functionalization and cross‐linking, yielding polypeptide hydrogels, can be achieved. TAD‐mediated conjugation can offer an interesting addition in the toolbox of selective (click‐like) polypeptide conjugation methodologies as it does not require functional non‐natural amino acids.
Recombinant protein design allows modular protein domains with different functionalities and responsive behaviors to be easily combined. Inclusion of these protein domains can enable recombinant proteins to have complex responses to their environment (e.g., temperature‐triggered aggregation followed by enzyme‐mediated cleavage for drug delivery or pH‐triggered conformational change and self‐assembly leading to structural stabilization by adjacent complementary residues). These “smart” behaviors can be tuned by amino acid identity and sequence, chemical modifications, and addition of other components. A wide variety of domains and peptides have smart behavior. This review focuses on protein designs for self‐assembly or conformational changes due to stimuli such as shifts in temperature or pH.
Natural and synthetic cross‐linked polymers allow the improvement of cytocompatibility and mechanical properties of the individual polymers. In osteochondral lesions of big size it will be required the use of scaffolds to repair the lesion. In this work a borax cross‐linked scaffold based on fumarate‐vinyl acetate copolymer and chitosan directed to osteochondrondral tissue engineering is developed. The cross‐linked scaffolds and physical blends of the polymers are analyzed in based on their morphology, glass transition temperature, and mechanical properties. In addition, the stability, degradation behavior, and the swelling kinetics are studied. The results demonstrate that the borax cross‐linked scaffold exhibits hydrogel behavior with appropriated mechanical properties for bone and cartilage tissue regeneration. Bone marrow progenitor cells and primary chondrocytes are used to demonstrate its osteo‐ and chondrogenic properties, respectively, assessing the osteo‐ and chondroblastic growth and maturation, without evident signs of cytotoxicity as it is evaluated in an in vitro system.
This study describes the development and cell culture application of nanometer thick photocrosslinkable thermoresponsive polymer films prepared by physical adsorption. Two thermoresponsive polymers, poly(N‐isopropylacrylamide (NIPAm)‐co‐acrylamidebenzophenone (AcBzPh)) and poly(NIPAm‐co‐AcBzPh‐co‐N‐tertbutylacrylamide) are investigated. Films are prepared both above and below the polymers' lower critical solution temperatures (LCSTs) and cross‐linked, to determine the effect, adsorption preparation temperature has on the resultant film. The films prepared at temperatures below the LCST are smoother, thinner, and more hydrophilic than those prepared above. Human pulmonary microvascular endothelial cell (HPMEC) adhesion and proliferation are superior on the films produced below the polymers LCST compared to those produced above. Cells sheets are detached by simply lowering the ambient temperature to below the LCST. Transmission electron, scanning electron, and light microscopies indicate that the detached HPMEC sheets maintain their integrity.
Here, the synthesis and characterization of three improved nanosystems is presented based on amino functionalized hyperbranched polyglycerol (hPG; Mw = 16.8 kDa) as potential copper(ii ) chelators. The ligands, N‐methyl‐N‐picolylglycine amide, 2,6‐pyridine dicarboxylic acid monoamide, and cyclam tetraacetic acid (TETA) monoamide, are covalently attached to the polymer with amide bonds. In this paper, the Cu(ii ) loading capacity, the stability of the Cu(ii )‐loaded carriers at different pHs, with competing ligands and in human serum, as well as the transport of Cu(ii ) in biological systems are investigated. For the first time, a different cytotoxicity of functionalized polymer nanoparticles with and without Cu(ii ) is observed. The cyclam‐based carrier combines the highest loading capacity (29 Cu ions/nanoparticle), best stability with respect to pH and EDTA (45% remaining Cu after 24 h), lowest cytotoxicity (IC50 > 100 × 10?6m (unloaded), 1500 × 10?6m Cu(ii ); Cu:carrier 29:1), and the highest stability in human serum.
The authors report a method to prepare cell‐laden, cell‐sized microparticles from various materials suitable for individual applications. The method includes a piezoelectric inkjetting technology and a horseradish peroxidase (HRP)‐catalyzed crosslinking reaction. The piezoelectric inkjetting technology enables production of cell‐laden, cell‐sized (20–60 μm) droplets from a polymer aqueous solution. The HRP‐catalyzed crosslinking of the polymer in the ejected solution enables production of spherical microparticles from various materials. Superior cytocompatibility of the microencapsulation method is confirmed from the viability and growth profiles of normal murine mammary gland epithelial cells.
The unicellular cyanobacterium Cyanothece sp. CCY 0110 is a highly efficient producer of extracellular polymeric substances (EPS), releasing up to 75% of the polymer to the culture medium. The carbohydrate polymer released to the medium (RPS) was previously isolated and characterized; it is composed of nine different monosaccharides including two uronic acids, and also containing peptides and sulfate groups. Here it is shown that the RPS spontaneously assembles with proteins at high concentrations leading to a phase transition. The proteins are released progressively and structurally intact near physiological conditions, primarily through the swelling of the polymer–protein matrix. The releasing kinetics of the proteins can be modulated through the addition of divalent cations, such as calcium. Notably, the polymer is not toxic to human dermal neonatal fibroblasts in vitro at RPS concentrations bellow 0.1 mg mL−1. The results show that this polymer is a good candidate for the delivery of therapeutic macromolecules.
A fully starch‐derived bioactive 3D porous scaffold is developed. The bioactivity is introduced through nanosized graphene oxide (nGO) derived from starch by microwave‐assisted degradation to carbon spheres and further oxidation to GO nanodots. nGO is covalently attached to starch to prepare functionalized starch (SNGO) via an esterification reaction. nGO and SNGO exhibit no cytotoxicity to MG63 at least up to 1000 µg mL−1 under (3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay. Porous scaffolds consisting of starch and SNGO (S/SNGO) or nGO (S/nGO) are prepared by freeze drying. The porosity and water uptake ability of the scaffolds depend on the concentration of nGO. Moreover, nGO, as a bioactive nanofiller, functions as an effective anchoring site for inducing CaP recrystallization in simulated body fluid. Among all modified starch‐based scaffolds, the S/SNGO scaffold containing the highest concentration of covalently attached SNGO (50%) induces the largest amount of hydroxyapatite, a type of CaP crystal that is closest to bone. The prepared 3D porous nGO functionalized scaffold, thus, exhibits potential promise for bone/cartilage tissue engineering.
Biocompatible polymeric coatings for metallic stents are desired, as currently used materials present limitations such as deformation during degradation and exponential loss of mechanical properties after implantation. These concerns, together with the present risks of the drug‐eluting stents, namely, thrombosis and restenosis, require new materials to be studied. For this purpose, novel poly(polyol sebacate)‐derived polymers are investigated as coatings for metallic stents. All pre‐polymers reveal a low molecular weight between 3000 and 18 000 g mol?1. The cured polymers range from flexible to more rigid, with E‐modulus between 0.6 and 3.8 MPa. Their advantages include straightforward synthesis, biodegradability, easy processing through different scaffolding techniques, and easy transfer to industrial production. Furthermore, electrospraying and dip‐coating procedures are used as proof‐of‐concept to create coatings on metallic stents. Biocompatibility tests using adipose stem cells lead to promising results for the use of these materials as coatings for metallic coronary stents.
Affinity‐based cell separation is label‐free and highly specific, but it is difficult to efficiently and gently release affinity‐captured cells due to the multivalent nature of cell‐material interactions. To address this challenge, we have developed a platform composed of a capture substrate and a cell‐releasing molecular trigger. The capture substrate is functionalized with a cell‐capture antibody and a coiled‐coil A . The cell‐releasing molecular trigger B ‐PEG (polyethylene glycol), a conjugate of a coiled‐coil B and polyethylene glycol, can drive efficient and gentle release of the captured cells, because A / B heterodimerization brings B ‐PEG to the substrate and PEG chains adopt extended conformations and break nearby multivalent antibody‐biomarker interactions. No enzymes or excessive shear stress are involved, and the released cells have neither external molecules attached nor endogenous cell‐surface molecules cleaved, which is critical for the viability, phenotype, and function of sensitive cells.
Cell sheet transplantation is a key tissue engineering technology. A vascular endothelial growth factor (VEGF)‐releasing fiber mat is developed for the transplantation of multilayered cardiomyocyte sheets. Poly(vinyl alcohol) fiber mats bearing poly(lactic‐co‐glycolic acid) nanoparticles that incorporate VEGF are fabricated using electrospinning and electrospray methods. Six‐layered cardiomyocyte sheets are transplanted with a VEGF‐releasing mat into athymic rats. After two weeks, these sheets produce thicker cardiomyocyte layers compared with controls lacking a VEGF‐releasing mat, and incorporate larger‐diameter blood vessels containing erythrocytes. Thus, local VEGF release near the transplanted cardiomyocytes induces vascularization, which supplies sufficient oxygen and nutrients to prevent necrosis. In contrast, cardiomyocyte sheets without a VEGF‐releasing mat do not survive in vivo, probably undergo necrosis, and are reduced in thickness. Hence, these VEGF‐releasing mats enable the transplantation of multilayered cardiomyocyte sheets in a single procedure, and should expand the potential of cell sheet transplantation for therapeutic applications.
Novel biodegradable polymers with specific properties, structures, and tailorable designs or modifications are in great demand. Poly(phosphoester)s with good biocompatibility and degradability, as well as other adjustable properties have been studied widely because of their potential in biomedical applications. To meet more versatile and diverse biomedical applications, a novel multiarm star‐shaped phosphorester triblock copolymer poly(amido amine)‐block‐poly(2‐butynyl phospholane)‐block‐poly(2‐methoxy phospholane) (PAMAM‐PBYP‐PMP) is synthesized via organo‐catalyzed sequential ring‐opening polymerization. Supramolecular micelles with good architectural stability are self‐assembled into uniform spherical morphology in aqueous solution. Doxorubicin (DOX) can be encapsulated into the micelles with efficient loading capacity. A slow and sustained release in the environment of simulated intracellular lysosome (pH 5.0 with phosphodiesterase I) is observed. In addition, the copolymers and DOX‐loaded supramolecular micelles exhibit low cell‐toxicity and excellent anticancer activity toward HeLa cells. As a consequence, this multiarm star‐shaped PAMAM‐PBYP‐PMP has great potential in drug delivery system for tumor treatment.
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