To tailor cell–surface interactions, precise and controlled attachment of cell‐adhesive motifs is required, while any background non‐specific cell and protein adhesion has to be blocked effectively. Herein, a versatile and highly reproducible antifouling surface modification based on “clickable” groups and hierarchically structured diblock copolymer brushes for the controlled attachment of cells is reported. The polymer brush architecture combines an antifouling bottom block of poly(2‐hydroxyethyl methacrylate) poly(HEMA) and an ultrathin azide‐bearing top block, which can participate in well‐established “click” reactions including the highly selective copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) reaction under mild conditions. This straightforward approach allows the rapid conjugation of a cell‐adhesive, alkyne‐bearing cyclic RGD peptide motif, enabling subsequent specific attachment of NIH 3T3 fibroblasts, their extensive proliferation and confluent cell sheet formation after 48 h of incubation. The generally applicable strategy presented in this report can be employed for surface functionalization with diverse alkyne‐bearing biological moieties via CuAAC or copper‐free alkyne‐azide cycloaddition protocols, making it a versatile functionalization approach and a promising tool for tissue engineering, biomaterial implant design, and other applications that require surfaces supporting highly specific cell attachment. 相似文献
Controlled presentation of biomolecules on synthetic substrates is an important aspect for biomaterials development. If the immobilization of multiple biomolecules is required, highly efficient orthogonal surface chemistries are needed to ensure the precision of the immobilization. In this communication, chemical vapor deposition (CVD) copolymerization is used to fabricate polymer coatings with controlled ratio of alkyne and pentafluorophenyl ester (Pfp‐ester) groups. Cyclic argine‐glycine‐aspartic acid (cRGD) adhesion peptide and epidermal growth factor (EGF) are immobilized through alkyne–azide cycloaddtion (“click” chemistry) and active ester–amine reaction, respectively. Cell studies with human umbilical vein endothelial cells (HUVEC) and A431 cell lines demonstrate the biological activity of the coimmobilized biomolecules. 相似文献
In a mixture of primary and secondary aliphatic amines, the primary amines were derivatized (masked) with o‐phthalaldehyde (OPA) followed by derivatization of the remaining secondary amines with ferrocenecarboxylic acid chloride (FAC). The “tagged” amines were analyzed by LC‐EC (liquid chromatography with electrochemical detection) using in‐series dual electrode detection. Chemically‐reversible oxidation of the FAC tagged secondary amines and their subsequent complementary oxidation and reduction signals coupled with chemically‐irreversible oxidation of OPA tagged primary amines provided the selectivity for quantitative secondary amine analysis. The procedure was also applied for the selective identification of fragment 4–11 (N‐terminus‐proline) of Substance P in the presence of other Substance P fragments with primary amino acids as their N‐termini. 相似文献
Chiral amplification is an interesting phenomenon in supramolecular chemistry mainly observed in complicated systems in which cooperative effect dominate. Herein, chiral, supramolecular, propeller‐like architectures have been constructed through coassembly of an achiral disk‐shaped molecule and chiral amino acid derivatives driven by intermolecular hydrogen bonding. Both the “sergeants‐and‐soldiers” principle and “majority‐rules” effect are applicable in these discrete four‐component supermolecules, which are the simplest supramolecular system ever reported that exhibit chiral amplification. 相似文献
A cobalt‐catalyzed dual annulation reaction for the synthesis of variously substituted indenoisoquinolinones from 2‐bromobenzaldehydes, amines, and methyl 2‐(ethynyl)benzoates has been developed. This method could also be applied to the synthesis of an array of highly functionalized bioactive indenoisoquinolinones and their derivatives. A possible mechanism of the cobalt catalysis is proposed, involving imine formation from bromobenzaldehyde and the amine, followed by a series of oxidative addition, alkyne insertion, cyclization reactions, and carbon–carbon double‐bond migration. The regioselective alkyne insertion plays an important role for the success of the second annulation. 相似文献
A simple and efficient method for the synthesis of γ,δ‐alkynyl‐β‐amino acid derivatives by a copper‐catalyzed three‐component amine–alkyne–alkyne addition reaction was developed. Various γ,δ‐alkynyl‐β‐amino acid derivatives were synthesized in moderate to good yields in one step. With chiral prolinol derivatives employed as the amine component, excellent diastereoselectivities (up to >99:1 diastereomeric ratio (dr)) were obtained. The scope of the reaction and further transformations of the resulting amino acid derivatives, such as deprotection and cyclization are also described. 相似文献
We have recently uncovered a general indium(I)‐catalyzed method for allylations and propargylation of acetals and ketals with a water‐ and air‐stable allyl boronate. By using a more reactive allyl borane, we have successfully extended this methodology to the more challenging C C coupling with ethers. Herein, we report an improved methodology for the indium(I)‐catalyzed allylation of acetals and ethers, through combination of the allyl boronate with a commercially available “hard” Lewis acid, B‐methoxy‐9‐BBN (BBN=borabicyclo[3.3.1]nonane), as an effective co‐catalyst. Significantly, our work highlights for the first time the correlation between the Lewis acidity of “electrophilic” boron‐based compounds and their “nucleophilic” reactivity in Csp3–Csp3 couplings, catalyzed by a “soft” low‐oxidation main group metal. In addition, we also report several applications of these methodologies to the selective synthesis of various carbohydrate derivatives. 相似文献
α‐Methoxy‐ω‐alkyne poly(ethylene glycol) (PEG) was tagged with pendent N‐hydroxy‐succinimidyl activated esters by photografting of a molecular clip. This easily synthesized heterofunctional PEG was found to be a versatile building block for (i) conjugation with an amino derivative and (ii) grafting to azido functional aliphatic polyesters backbone by Huisgen's 1,3‐dipolar cycloaddition. This original combination of “clip” and “click” reactions provides a versatile and straightforward pathway for the synthesis of functional amphiphilic and degradable copolymers valuable for biomedical applications such as in drug‐delivery.
The specific capture and remotely controlled release of the EpCAM‐positive cancer cells from biotin‐doped polypyrrole (Ppy) films in response to an electrical potential is presented. As Ppy allows the direct incorporation of biotin molecules during the electrochemical process, densely packed biotin molecules can serve as the binding sites for streptavidin‐tagged biomolecular complexes. This study demonstrates not only the enhanced capture and enrichment of EpCAM‐positive cancer cells but also “on‐demand” release of the viable cells from conductive Ppy in an electrical‐potential‐dependent way. This novel approach is of great importance in a diverse range of applications, and in particular in cancer diagnostics and screening. 相似文献
Platinum(0) Complexes with Amino‐Substituted Alkynes: Novel Organometallic Building Blocks for Supramolecular Architectures and “Crystal Engineering” Homoleptic Bis(alkyne)platinum(0) compounds containing either NH2‐ or NH2‐/OH‐substituents are formed by reaction of Pt(cod)2 with alkynes as stable compounds. They can be used as variable building blocks for supramolecular networks. The crystal structure analyses of Bis(2‐amino‐2,5dimethyl‐5‐hydroxy‐hex‐3‐yne)platinum(0) ( 1 ) and of Bis(1(3‐amino‐3‐methyl‐but‐1‐inyl)‐cyclohexane‐1‐ol)platinum(0) ( 2 ) exhibit that the low‐valent Pt atom is tetrahedrally surrounded by the four sp‐hybridizated carbonatoms of the alkynes. Despite the fact that the bond lengths and ‐angles of the PtC4 units are equal, the supramolecular structures are different. While in 1 polymer strands are formed in which the bis(alkyne)‐Pt0 units are connected by (OH)2(NH2)2‐ tetrahedrons, 2 yields only a dimer containing a network of four OH‐ and two NH2‐groups. Platinum(0) complexes with cationic alkynes bearing ammonium substituents can be isolated as thermal stable compounds. The X‐ray structures of [Cl( FH +)Pt(cod)]4 ( 8 ) reveals that four molecular units form a cube with both four NH3+ groups and Cl– at the corners connected by hydrogen bridges. In the bis(alkyne)Pt0 complex [Cl1.5( FH +)1.5( F )0.5Pt] ( 9 ) only 1,33 of two NH2 groups are protonated and a hydrogen bridged network connects four bis(alkyne)Pt0 units (cod: cycloocta‐1.5‐diene, F : 1‐(trimethylsilylethinyl)‐1‐amino‐cyclohexane). 相似文献