Ureidopyrimidinone Research Articles

Using a Supramolecular Monomer Formulation Approach to Engineer Modular, Dynamic Microgels, and Composite Macrogels.

Microgels show advantages over bulk hydrogels due to convenient control over microgel size and composition, and the ability to use microgels to modularly construct larger hierarchical scaffold hydrogel materials. Here, supramolecular chemistry is used to formulate supramolecular polymer, dynamic microgels solely held together by non-covalent interactions. Four-fold hydrogen bonding ureido-pyrimidinone (UPy) monomers with different functionalities are applied to precisely tune microgel properties in a modular way, via variations in monomer concentration, bifunctional crosslinker ratio, and the incorporation of supramolecular dyes and peptides. Functionalization with a bioactive supramolecular cell-adhesive peptide induced selectivity of cells toward the bioactive microgels over non-active, non-functionalized versions. Importantly, the supramolecular microgels can also be applied as microscale building blocks into supramolecular bulk macrogels with tunable dynamic behavior: a robust and weak macrogel, where the micro- and macrogels are composed of similar molecular building blocks. In a robust macrogel, microgels act as modular micro-building blocks, introducing multi-compartmentalization, while in a weak macrogel, microgels reinforce and enhance mechanical properties. This work demonstrates the potential to modularly engineer higher-length-scale structures using small molecule supramolecular monomers, wherein microgels serve as versatile and modular micro-building units.

Eco‐Friendly, Recyclable Supramolecular Inks Incorporating Multi‐Walled Carbon Nanotubes

AbstractIn contemporary society, with its emphasis on environmental stewardship, the development of “green” (eco‐friendly) inks is of paramount importance. These inks are utilized across a broad spectrum of applications, ranging from the printing of packaging material to the 3D printing of functional components. This study explores the synthesis of eco‐friendly, biodegradable supramolecular polymer materials predicated on ureido‐pyrimidinone (UPy). The subsequent formulation of these materials into functional inks is achieved by the incorporation of multi‐walled carbon nanotubes (MWCNTs). These resultant inks exhibit outstanding photothermal conversion properties, robust electrical conductivity, intrinsic self‐repair capabilities, and superior writability. Moreover, this research demonstrates the recyclability of MWCNTs within the ink matrix, exhibiting a recovery efficiency of ≈90%. Such a high recovery rate offers a novel perspective on the sustainable reuse of conductive fillers in polymer‐based inks.

Ultratough Supramolecular Polyurethane Featuring an Interwoven Network with Recyclability, Ideal Self-Healing and Editable Shape Memory Properties.

Developing multifunctional polymers with excellent mechanical properties, outstanding shape memory characteristics, and good self-healing properties is a formidable challenge. Inspired by the woven cross-linking strategy, a series of supramolecular polyurethane (PU) with an interwoven network structure composed of covalent and supramolecular cross-linking nodes have been successfully synthesized by introducing the ureido-pyrimidinone (UPy) motifs into the PU skeleton. The best-performing sample exhibited ultrahigh strength (∼77.2 MPa) and toughness (∼312.7 MJ m-3), along with an ideal self-healing efficiency (up to 90.8% for 6 h) and satisfactory temperature-responsive shape memory effect (shape recovery rates up to 96.9%). Furthermore, it ensured recyclability. These favorable properties are mainly ascribed to the effective dissipation of strain energy due to the disassembly and reconfiguration of supramolecular nodes (i.e., quadruple hydrogen bonds (H-bonds) between UPy units), as well as the covalent cross-linking nodes that maintain the integrity of the polymer network structure. Thus, our work provides a universal strategy that breaks through the traditional contradictions and paves the way for the commercialization of high-performance multifunctional PU elastomers.

Easy Processable Photomechanical Thin Film Involving a Photochromic Diarylethene and a Thermoplastic Elastomer in Supramolecular Interaction.

A novel supramolecular photoactuator in the form of a thin film of centimetric size has been developed as an alternative to traditional liquid crystal elastomers (LCE) involving azobenzene (AZO) units or photochromic microcrystals. This thin film is produced through spin coating without the need for alignment or crosslinking. The photoactuator combines a photochromic dithienylethene (DTE) functionalized with ureidopyrimidinone (UPy) units, and a telechelic thermoplastic elastomer, also functionalized with UPy, allowing quadruple hydrogen bonding between the two components. Upon alternating ultraviolet (UV) and visible light exposure, the film exhibits reversible bending and color changes, studied using displacement and absorption tracking setups. For the first time, the photomechanical effect (PME) is quantitatively correlated with photochromism, showing that DTE units drive the movement under both UV (photocyclization) and visible (photoreversion) light. In situ illumination techniques reveal that the PME arises from photoinduced strain within 160 nm UPy-bonded DTE domains, which expand and contract by approximately 50% under UV and visible light, respectively. The semicrystalline nature of the elastomer and a robust supramolecular network connecting both components are critical in converting microscopic photostrain into macroscopic actuation.

Tuning Structural Organization via Molecular Design and Hierarchical Assembly to Develop Supramolecular Thermoresponsive Hydrogels.

The cellular microenvironment is composed of a dynamic hierarchical fibrillar architecture providing a variety of physical and bioactive signals to the surrounding cells. This dynamicity, although common in biology, is a challenge to control in synthetic matrices. Here, responsive synthetic supramolecular monomers were designed that are able to assemble into hierarchical fibrous structures, combining supramolecular fiber formation via hydrogen bonding interactions, with a temperature-responsive hydrophobic collapse, resulting in cross-linking and hydrogel formation. Therefore, amphiphilic molecules were synthesized, composed of a hydrogen bonding ureido-pyrimidinone (UPy) unit, a hydrophobic alkyl spacer, and a hydrophilic oligo(ethylene glycol) tail. The temperature responsive behavior was introduced by functionalizing these supramolecular amphiphiles with a relatively short poly(N-isopropylacrylamide) (PNIPAM) chain (M n ∼ 2.5 or 5.5 kg/mol). To precisely control the assembly of these monomers, the length of the alkyl spacer between the UPy moiety and PNIPAM was varied in length. A robust sol-gel transition, with the dodecyl UPy-PNIPAM molecule, was obtained, with a network elasticity enhancing over 2000 times upon heating above room temperature. The UPy-PNIPAM compounds with shorter alkyl spacers were already hydrogels at room temperature. The sol-gel transition of the dodecyl UPy-PNIPAM hydrogelator could be tuned by the incorporation of different UPy-functionalized monomers. Furthermore, we demonstrated the suitability of this system for microfluidic cell encapsulation through a convenient temperature sol-gel transition. Our results indicate that this novel thermoresponsive supramolecular system offers a modular platform to study and guide single-cell behavior.

Verification of the Self-Healing Ability of PP-co-HUPy Copolymers in Epoxy Systems.

This work concerns the verification of the self-healing ability of PP-co-HUPy copolymers dispersed in epoxy systems. PP is the acronym for the Poly-PEGMA polymer, and HUPy refers to the HEMA-UPy copolymers based on ureidopyrimidinone (UPy) moieties. In particular, this work aims to verify whether this elastomer characterized by an intrinsic self-healing ability can activate supramolecular interactions among polymer chains of an epoxy resin, as in the elastomer alone. The elastomer includes a class of polyethylene glycol monomethyl ether methacrylate-based copolymers, with different percentages of urea-N-2-amino-4-hydroxy-6-methyl pyrimidine-N'-(hexamethylene-n-carboxyethyl methacrylate) (HEMA-UPy) co-monomers. The self-healing capability of these copolymers based on possible quadruple hydrogen bond interactions between polymer chains has been verified. The formulated epoxy samples did not show self-healing efficiency. This can be attributed to the formation of phase segregation that originates during the curing process of the samples, although the PP-co-HUPy copolymers are completely soluble in the liquid epoxy matrix EP. The morphological investigation highlighted the presence of crystals of PP-co-HUPy copolymers, which are in greater quantity in the sample containing the highest weight percentage (7.8 wt%) of HUPy units. Furthermore, the crystals act as promotors for increasing the curing degree (DC) of the epoxy systems containing HUPy units. DC goes from 91.6% for EP to 96.1% and 95.4% for the samples containing weight percentages of 2.5 and 7.8 wt% of HUPy units, respectively. Dynamic mechanical analysis (DMA) shows storage modulus values for epoxy systems containing PP-co-HUPy units lower than that of the unfilled resin EP. The values of maximum in Tan δ (Tg), representing the temperature at which the glass transition occurs, are 220 for the unfilled resin EP, 228 for the sample containing 2.5 wt% of HEMA-UPy units, and 211 for the sample containing 7.8 wt% of HEMA-UPy units.

Comparison and investigation of H-bond assisted reusable PU adhesives with high shear strength

Hot-melt adhesive (HMA) is commonly used in industrial manufacturing due to its ease of use. However, the direct factors that affect shear strength have been unclear in recent years, making it difficult to prepare hot melt adhesives with high shear strength, which are mostly lower than 6 MPa. In this study, three types of polyurethane HMAs, differing in the position of H-bond motifs, ureidopyrimidinone (UPy), were synthesized and characterized, the most central factor for shear strength, Young's modulus, was firstly found out and proved. Side-chain UPy provides better flexibility and more chain entanglement. The lap shear strength of SPU was about 13.48 MPa, which was the highest shear strength of PU HMA, and remained 73.4 % even after 4 cycles. Compared to the other two samples, the side-chain motifs improved the possibility of forming hydrogen bonds with adherends and increased chain mobility. This led to a more efficient wetting process and strengthened Young's modulus directly, enhancing adhesive property incomparably. This work provides a satisfactory method for achieving high shear strength in HMA.

Liquid Metal‐Enhanced Highly Adhesive Electrodes for Multifunctional Epidermal Bioelectronics

AbstractLiquid metal (LM) bioelectronics find widespread uses in healthcare devices and medical implants. However, the current LM‐based electrodes suffer from achieving a combination of features including stable conductivity, high tissue adhesion, stability, good biocompatibility, degradability, and recyclability. In this work, a stable LM electrode is prepared with an extremely high adhesion strength (8.9 MPa), which is tunable in a wide range by introducing an adhesive ureidopyrimidinone (UPy)‐based polymer to harvest the abovementioned properties. With the help of dynamic LM particle‐polymer interactions in the polymer matrix, LMs can not only enhance the adhesion properties but also form a percolated network at a low LM loading (38 vol%) to achieve a high conductance stability (R/R0 = 0.76 at 100% strain). The high adhesion strength provides a highly stable electrical connection with rigid components with a high stretchability of 1154% when mounting a resistor, while a relatively low adhesion makes it a comfortable wounded skin‐interfaced electrode for accelerating wound healing. Taking advantage of their tunable surface adhesion and biocompatibility, the as‐prepared LM electrodes provide a more reliable and friendly approach to the development of healthcare devices.

Merging Modular Molecular Design with High Throughput Screening of Cell Adhesion on Antimicrobial Supramolecular Biomaterials.

A polymer microarray based on the supramolecular ureido-pyrimidinone (UPy) moiety is fabricated to screen antimicrobial materials for their ability to support cell adhesion. UPy-functionalized additives, either cell-adhesive, antimicrobial or control peptides, are used, and investigated in different combinations at different concentrations, resulting in a library of 194 spots. These are characterized on composition and morphology to evaluate the microarray fabrication. Normal human dermal fibroblasts are cultured on the microarrays and cell adhesion to the spots is systematically analyzed. Results demonstrate enhanced cell adhesion on spots with combinations including the antimicrobial peptides. This study clearly proves the power of the high throughput approach in combination with supramolecular molecules, to screen additive libraries for desired biological response.

Physically crosslinked polyacrylates by quadruple hydrogen bonding side chains.

Dynamic polymer materials can be obtained by introducing supramolecular interactions between the polymer chains. Here we report on the preparation and mechanical properties of poly(methyl acrylate) (PMA) and poly(n-butyl acrylate) (PBA) funcionalized with ureidopyrimidinone (UPy) in the side chains. In contrast to the traditional UPy with a methyl group, the selected UPy motif contained a branched alkyl side chain, which enhances solubility, compatibility with the polymer matrix and potentially prevents stacking of UPy dimers. Low molar mass PMA and PBA were synthesized via Cu(0)-mediated radical polymerization and allyl bonds were introduced with different degrees of functionalization by stoichiometrically controlled transesterification with allyl alcohol. The allyl esters served as functional handles for UPy attachment via UV-initiated radical thiol-ene coupling. The PMA-UPy materials displayed a more glassy appearance, in contrast to the rubbery PBA-UPy polymer networks, associated to its higher glass transition temperature. The mechanical properties of the resulting hydrogen bonded polymer networks were assessed by thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical thermal analysis and tensile testing, followed by rheological analysis of the network dynamics. Furthermore, the effect of associative groups on the linear viscoelastic response is discussed based on a modified sticky Rouse model indicating the absence of significant aggregation or phase separation of the UPY units.

Investigating the self-assembly of 2NapFF and ureido-pyrimidinone multicomponent systems for cell culture.

Low molecular weight gels are formed via the self-assembly of small molecules into fibrous structures. In the case of hydrogels, these networks entrap large volumes of water, yielding soft materials. Such gels tend to have weak mechanical properties and a high permeability for cells, making them particularly appealing for regenerative medicine applications. Ureido-pyrimidinone (UPy) supramolecular gelators are self-assembling systems that have demonstrated excellent capabilities as biomaterials. Here, we combine UPy-gelators with another low molecular weight gelator, the functionalized dipeptide 2NapFF. We have successfully characterized these multicomponent systems on a molecular and bulk scale. The addition of 2NapFF to a crosslinked UPy hydrogel significantly increased hydrogel stiffness from 30 Pa to 1300 Pa. Small-angle X-ray scattering was used to probe the underlying structures of the systems and showed that the mixed UPy and 2NapFF systems resemble the scattering data produced by the pristine UPy systems. However, when a bifunctional UPy-crosslinker was added, the scattering was close to that of the 2NapFF only samples. The results suggest that the crosslinker significantly influences the assembly of the low molecular weight gelators. Finally, we analysed the biocompatibility of the systems using fibroblast cells and found that the cells tended to spread more effectively when the crosslinking species was incorporated. Our results emphasise the need for thorough characterisation at multiple length scales to finely control material properties, which is particularly important for developing novel biomaterials.

The effect of charge and albumin on cellular uptake of supramolecular polymer nanostructures.

Intracellular delivery of functional biomolecules by using supramolecular polymer nanostructures has gained significant interest. Here, various charged supramolecular ureido-pyrimidinone (UPy)-aggregates were designed and formulated via a simple "mix-and-match" method. The cellular internalization of these UPy-aggregates in the presence or absence of serum proteins by phagocytic and non-phagocytic cells, i.e., THP-1 derived macrophages and immortalized human kidney cells (HK-2 cells), was systematically investigated. In the presence of serum proteins the UPy-aggregates were taken up by both types of cells irrespective of the charge properties of the UPy-aggregates, and the UPy-aggregates co-localized with mitochondria of the cells. In the absence of serum proteins only cationic UPy-aggregates could be effectively internalized by THP-1 derived macrophages, and the internalized UPy-aggregates either co-localized with mitochondria or displayed as vesicular structures. While the cationic UPy-aggregates were hardly internalized by HK-2 cells and could only bind to the membrane of HK-2 cells. With adding and increasing the amount of serum albumin in the cell culture medium, the cationic UPy-aggregates were gradually taken up by HK-2 cells without anchoring on the cell membranes. It is proposed that the serum albumin regulates the cellular internalization of UPy-aggregates. These results provide fundamental insights for the fabrication of supramolecular polymer nanostructures for intracellular delivery of therapeutics.

Hydrogel‐Based Delivery of antimiR‐195 Improves Cardiac Efficacy after Ischemic Injury

AbstractMicroRNAs (miRs) are potent regulators of biology and disease. The miR‐15 family is shown to regulate cardiomyocyte proliferation and antimiR‐based inhibition induces a cardioprotective effect after myocardial infarction in mice. However, systemic delivery of antimiRs leads to accumulation in kidneys and liver, with relatively poor cardiac exposure. Injectable hydrogels are proposed to serve as sustained‐release drug delivery depots and can potentially be used to improve cardiac efficacy of antimiR therapeutics. Here, the effect of a hydrogel‐formulated antimiR‐195 after myocardial infarction in mice is studied. For this, an injectable, pH‐switchable supramolecular hydrogel based on poly(ethylene glycol) (PEG) functionalized with hydrogen bonding ureido‐pyrimidinone (UPy) units is used. Intracardiac injections under baseline conditions of this UPy–PEG hydrogelator induce a transient inflammatory response that is no longer present 7 days postinjection. In vitro experiments show that antimiR‐195 is released from the gel, and induces microRNA inhibition leading to downstream cardiomyocyte proliferation. In vivo, intramyocardial delivery of antimiR‐195 in UPy–PEG enhances cardiac target derepression compared to phosphate‐buffered‐saline‐dissolved antimiR‐195, despite a low cardiac retention. After ischemic injury, this translates into a greater therapeutic effect by increasing both target derepression and cardiomyocyte proliferation. Intramyocardial injection of UPy–PEG‐formulated antimiR‐195 is sufficient to improve cardiac efficacy of antimiR‐195.

Recastable assemblies of carbon dots into mechanically robust macroscopic materials

Assembly of nanoparticles into macroscopic materials with mechanical robustness, green processability, and recastable ability is an important and challenging task in materials science and nanotechnology. As an emerging nanoparticle with superior properties, macroscopic materials assembled from carbon dots will inherit their properties and further offer collective properties; however, macroscopic materials assembled from carbon dots solely remain unexplored. Here we report macroscopic films assembled from carbon dots modified by ureido pyrimidinone. These films show tunable fluorescence inherited from carbon dots. More importantly, these films exhibit collective properties including self-healing, re-castability, and superior mechanical properties, with Young’s modulus over 490 MPa and breaking strength over 30 MPa. The macroscopic films maintain original mechanical properties after several cycles of recasting. Through scratch healing and welding experiments, these films show good self-healing properties under mild conditions. Moreover, the molecular dynamics simulation reveals that the interplay of interparticle and intraparticle hydrogen bonding controls mechanical properties of macroscopic films. Notably, these films are processed into diverse shapes by an eco-friendly hydrosetting method. The methodology and results in this work shed light on the exploration of functional macroscopic materials assembled from nanoparticles and will accelerate innovative developments of nanomaterials in practical applications.

Stability of Quadruple Hydrogen Bonds in an Ionic Liquid Environment.

Hydrogen bonds (H-bonds) are highly sensitive to the surrounding environments owing to their dipolar nature, with polar solvents kown to significantly weaken H-bonds. Herein, the stability of the H-bonding motif ureidopyrimidinone (UPy) is investigated, embedded into a highly polar polymeric ionic liquid (PIL) consisting of pendant pyrrolidinium bis(trifluoromethylsulfonyl)imide (IL) moieties, to study the influence of such ionic environments on the UPy H-bonds. The content of the surrounding IL is changed by addition of an additional low molecular weight IL to further boost the IL content around the UPy moieties in molar ratios of UPy/IL ranging from 1/4 up to 1/113, thereby promoting the polar microenvironment around the UPy-H-bonds. Variable-temperature solid-state MAS NMR spectroscopy and FT-IR spectroscopy demonstrate that the UPy H-bonds are largely present as (UPy-) dimers, but sensitive to elevated temperatures (>70°C). Subsequent rheology and DSC studies reveal that the ILs only solvate the polymeric chains but do not interfere with the UPy-dimer H-bonds, thus accounting for their high stability and applicability in many material systems.

Development of a Fully Synthetic Corneal Stromal Construct via Supramolecular Hydrogel Engineering.

Recent advances in the field of ophthalmology show great potential in the design of bioengineered constructs to mimic the corneal stroma. Hydrogels based on synthetic supramolecular polymers, are attractive synthetic mimics of the natural highly hydrated corneal stroma. Here, a fully synthetic corneal stromal construct is developed via engineering of an injectable supramolecular hydrogel based on ureido-pyrimidinone (UPy) moieties. The hydrogel displays a dynamic and tunable behavior, which allows for control of biochemical and mechanical cues. Two hydrogels are developed, a fully synthetic hydrogel functionalized with a bioactive cyclic arginine-glycine-aspartate UPy (UPy-cRGD) additive, and a hybrid hydrogel based on UPy-moieties mixed with collagen type I fibers. Both hydrogels supported cell encapsulation and associated cellular deposition of extracellular matrix (ECM) proteins after 21 days. Excitingly, the hydrogels support the activation of isolated primary keratocytes into stromal fibroblasts as well as the differentiation toward more quiescent corneal stromal keratocytes, demonstrated by their characteristic long dendritic protrusions and a substantially diminished cytokine secretion. Furthermore, cells survive shear stresses during an injectability test. Together, these findings highlight the development of an injectable supramolecular hydrogel as a synthetic corneal stromal microenvironment able to host primary keratocytes.

Iron Oxide Nanoparticles with Supramolecular Ureido-Pyrimidinone Coating for Antimicrobial Peptide Delivery.

Antimicrobial peptides (AMPs) can kill bacteria by disrupting their cytoplasmic membrane, which reduces the tendency of antibacterial resistance compared to conventional antibiotics. Their possible toxicity to human cells, however, limits their applicability. The combination of magnetically controlled drug delivery and supramolecular engineering can help to reduce the dosage of AMPs, control the delivery, and improve their cytocompatibility. Lasioglossin III (LL) is a natural AMP form bee venom that is highly antimicrobial. Here, superparamagnetic iron oxide nanoparticles (IONs) with a supramolecular ureido-pyrimidinone (UPy) coating were investigated as a drug carrier for LL for a controlled delivery to a specific target. Binding to IONs can improve the antimicrobial activity of the peptide. Different transmission electron microscopy (TEM) techniques showed that the particles have a crystalline iron oxide core with a UPy shell and UPy fibers. Cytocompatibility and internalization experiments were carried out with two different cell types, phagocytic and nonphagocytic cells. The drug carrier system showed good cytocompatibility (>70%) with human kidney cells (HK-2) and concentration-dependent toxicity to macrophagic cells (THP-1). The particles were internalized by both cell types, giving them the potential for effective delivery of AMPs into mammalian cells. By self-assembly, the UPy-coated nanoparticles can bind UPy-functionalized LL (UPy-LL) highly efficiently (99%), leading to a drug loading of 0.68 g g-1. The binding of UPy-LL on the supramolecular nanoparticle system increased its antimicrobial activity against E. coli (MIC 3.53 µM to 1.77 µM) and improved its cytocompatible dosage for HK-2 cells from 5.40 µM to 10.6 µM. The system showed higher cytotoxicity (5.4 µM) to the macrophages. The high drug loading, efficient binding, enhanced antimicrobial behavior, and reduced cytotoxicity makes ION@UPy-NH2 an interesting drug carrier for AMPs. The combination with superparamagnetic IONs allows potential magnetically controlled drug delivery and reduced drug amount of the system to address intracellular infections or improve cancer treatment.

Engineering antimicrobial supramolecular polymer assemblies

AbstractAntibacterial resistance against conventional antibiotics has emerged as a global health problem. To address this problem, antimicrobial peptides (AMPs) have been recognized as alternatives due to their fast‐killing activity and less propensity to induce resistance. Here, the AMPs are engineered via a supramolecular fashion to control and increase their biological performance. The AMPs are modified with ureido‐pyrimidinone (UPy) to obtain UPy‐AMP monomers, followed by modular self‐assembling to realize antibacterial UPy‐AMP supramolecular polymers. These positively charged assemblies are illustrated as stable, short fibrous or rod‐like UPy‐AMP nanostructures with enhanced antibacterial activity and modulable cytotoxicity. Moreover, these antibacterial UPy‐AMP assemblies can be internalized by both THP‐1 derived macrophages and human kidney cells, which would be an effective potential therapy to deliver the AMPs into mammalian cells to address intracellular infections. Overall, the results present here demonstrate that supramolecular engineering of AMPs provides a powerful tool to enhance the antibacterial activity, modulate cytotoxicity and accelerate the clinical application of AMPs.

Heparin‐guided binding of vascular endothelial growth factor to supramolecular biomaterial surfaces

AbstractGrowth factors can steer the biological response to a biomaterial post implantation. Heparin is a growth factor binding molecule that can coordinate growth factor presentation to cells and therefore is able to regulate many biological processes. One way to functionalize biomaterials with heparin and growth factors is via a supramolecular approach. Here, we show a proof‐of‐concept study in which a supramolecular approach based on ureido‐pyrimidinone (UPy) was used, which allows for modular functionalization. PCLdiUPy was functionalized with a UPy‐modified heparin binding peptide (UPy‐HBP) to facilitates binding of heparin, which in turn can bind vascular endothelial growth factor (VEGF) via its heparin binding domain. The adsorption of both heparin and VEGF were studied in two different functionalization approaches (pre‐complex and two‐step) and at different molecular ratios. Quartz crystal microbalance with dissipation energy adsorption data showed that VEGF and pre‐complexed heparin:VEGF adsorbed non‐specifically, with no distinguish between non‐specific adsorption and heparin guided‐adsorption. On the biological side, heparin guided‐adsorption of Heparin:VEGF enhanced HUVECs surface coverage as compared to non‐specific adsorption. These results provide a detailed insight on the molecular sandwich which is useful for new design strategies of supramolecular biomaterials with well‐controlled immobilization of different growth factors.

Design, Synthesis, and Characterization of Semiconducting Polymers Incorporating a Ring-like Ureidopyrimidinone (UPy) Quadruple Hydrogen Bonding Structure

Design, Synthesis, and Characterization of Semiconducting Polymers Incorporating a Ring-like Ureidopyrimidinone (UPy) Quadruple Hydrogen Bonding Structure