Polyaspartamide Derivatives Research Articles

Rational design of solid lipid-polymer hybrid nanoparticles: An innovative glycoalkaloids-carrier with potential for topical melanoma treatment

Despite the promising potential of Solanum plant glycoalkaloids in combating skin cancer, their clinical trials have been halted due to dose-dependent toxicity and poor water solubility. In this study, we present a rational approach to address these limitations and ensure colloidal stability of the nanoformulation over time by designing solid lipid-polymer hybrid nanoparticles (SLPH). Leveraging the biocompatible and cationic properties of polyaspartamides, we employed a new polyaspartamide derivative (P1) as a raw material for this class of nanostructures. Subsequently, we prepared SLPH through a one-step process involving hot-melt emulsification followed by ultrasonication. The physicochemical properties of the SLPH were thoroughly characterized using dynamic light scattering (DLS), ζ-potential analysis, nanoparticle tracking analysis (NTA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). The optimized formulation exhibited long-term stability over six months under low temperatures, maintaining a particle size around 200 nm, a polydispersity index (PdI) lower than 0.2, and a ζ-potential between +35–40 mV. Furthermore, we evaluated the cytotoxic effect of the SLPH against human cutaneous melanoma cells (SK-MEL-28) compared to human foreskin fibroblast cells (HFF-1). Encapsulation of glycoalkaloids into the nanoparticles (SLPH-GE) resulted in a two-fold greater selective cytotoxic profile for melanoma cells than glycoalkaloids-free (GE). The nanoparticles disrupted the stratum corneum barrier with a penetration depth of approximately 77 μm. These findings underscore the potential of the developed nanosystem as an effective glycoalkaloid carrier with suitable colloidal and biological properties for further studies in topical treatment strategies for cutaneous melanoma.

Enhanced adhesion of novel biomass‐based biomimetic adhesives using polyaspartamide derivative with lignin

AbstractWith the decreasing of petrochemical resources and the increasing severity environmental pollution, the development of environmentally friendly adhesive technology using renewable resources has attracted more and more attention. Inspired by mussels, a novel biomimetic adhesive synthesized using polyaspartamide derivative (PolyAspAm(DOPA/OA)) and alkali lignin (AL). The physical/chemical structure and properties were examined by 1H‐NMR, Fourier‐transform infrared spectroscopy, thermo gravimetric analysis, scanning electron microscopy, water absorption, in vitro cytotoxicity, lap shear tensile, and three‐point bending tests. The adhesive capacity was improved significantly when AL added into PolyAspAm(DOPA/OA). The lap shear tensile for four different substrates (metal and plastic) both increased greatly. The underwater adhesion test possessed good underwater adhesion properties. The results confirmed that hydrogen bonds and chain entanglement were formed between PolyAspAm(DOPA/OA) and AL. It was the introduction of catechol groups and physical–chemical interactions between PolyAspAm(DOPA/OA) and AL improved the adhesion strength and water resistance of the adhesive. Moreover, the corn stover non‐wood boards were prepared by one‐step hot pressing using PolyAspAm(DOPA/OA) with AL adhesives. The three‐point bending of corn stover non‐wood boards increased from 5.00 ± 0.03 to 14.85 ± 20.1 MPa. Overall, this work shows that a nontoxic, environmentally friendly PolyAspAm(DOPA/OA) with AL adhesive has extensive application prospects.

Hydrophobicity Tuning of Cationic Polyaspartamide Derivatives for Enhanced Antisense Oligonucleotide Delivery.

Various cationic polymers are used to deliver polyplex-mediated antisense oligonucleotides (ASOs). However, few studies have investigated the structural determinants of polyplex functionalities in polymers. This study focused on the polymer hydrophobicity. A series of amphiphilic polyaspartamide derivatives possessing various hydrophobic (R) moieties together with cationic diethylenetriamine (DET) moieties in the side chain (PAsp(DET/R)s) were synthesized to optimize the R moieties (or hydrophobicity) for locked nucleic acid (LNA) gapmer ASO delivery. The gene knockdown efficiencies of PAsp(DET/R) polyplexes were plotted against a hydrophobicity parameter, logD7.3, of PAsp(DET/R), revealing that the gene knockdown efficiency was substantially improved by PAsp(DET/R) with logD7.3 higher than -2.4. This was explained by the increased polyplex stability and improved cellular uptake of ASO payloads. After intratracheal administration, the polyplex samples with a higher logD7.3 than -2.4 induced a significantly higher gene knockdown in the lung tissue compared with counterparts with lower hydrophobicity and naked ASO. These results demonstrate that the hydrophobicity of PAsp(DET/R) is crucial for efficient ASO delivery in vitro and in vivo.

Adhesive Composite Hydrogel Patch Based on a Polyaspartamide Derivative to Treat Atopic Dermatitis

AbstractTransdermal patches offer significant advantages as a drug delivery system due to their ability to bypass first‐pass metabolism, sustain drug release, and provide predetermined dose and application area. However, to be effective, transdermal patches must have optimal adhesion and drug‐loading capacity. In this study, an adhesive composite hydrogel patch consisting of poly(N‐2,3‐dihydroxypropyl aspartamide) (PDHPA), a polyaspartamide derivative, and mesoporous silica nanoparticles (MSNs) are developed. To prepare the hydrogel, boric acid (BA) is utilized as a crosslinker to form reversible bonds between multiple hydroxyl groups in the polymer and BA. The PDHPA‐BA hydrogel exhibits dynamic reversibility, self‐healing properties, and a pH‐dependent sol–gel transition. The addition of MSNs with abundant hydroxyl groups improves the mechanical performance, adhesion properties, and self‐healing rate of the PDHPA‐BA hydrogel. In addition, MSNs enable the loading of hydrophobic drugs, such as dexamethasone (Dex), onto the hydrogel. Using the Dex‐loaded adhesive composite hydrogel as a transdermal patch, the severity of atopic dermatitis in a mouse model indicated by suppression of dermatitis score, epidermal thickness, number of mast cells, and serum interleukin‐4 levels is successfully reduced. These results suggest that the composite hydrogel patch is a highly promising transdermal drug delivery system for effectively treating inflammatory skin diseases.

Fine-tuning of polyaspartamide derivatives with alicyclic moieties for systemic mRNA delivery

Development of efficient delivery vehicles for in vitro transcribed mRNA (IVT mRNA) is currently a major challenge in nanomedicines. For systemic mRNA delivery, we developed a series of cationic amphiphilic polyaspartamide derivatives (PAsp(DET/R)s) carrying various alicyclic (R) moieties with diethylenetriamine (DET) in the side chains to form mRNA-loaded polyplexes bearing stability under physiological conditions and possessing endosomal escape functionality. While the size and ζ-potential of polyplexes were comparable among various PAsp(DET/R)s, the transfection efficiencies of polyplexes were considerably varied due to difference in the R moieties of PAsp(DET/R)s and were described by an octanol–water (or buffer at pH 7.3) distribution coefficient (logD7.3). The critical logD7.3 for the efficient in vitro transfection of mRNA was indicated at −2.7 to −1.8. The polyplexes with logD7.3 > −1.8 elicited the much higher in vitro transfection efficiencies. After systemic administration, the polyplexes with logD7.3 from −1.8 to −1.3 elicited the significant mRNA expression specifically in the lungs. The highest mRNA expression in the lungs was achieved by a polyaspartamide derivative having a cyclohexylethyl group (PAsp(DET/CHE)), which induced more than 10-fold increase in mRNA transfection efficiency compared to commercially available lipid nanoparticles. The higher mRNA expression by polyplexes in the lungs was explained well by the preferential lung accumulation of intact mRNA, as determined by quantitative real-time PCR. Our results demonstrate that PAsp(DET/R)s are a promising synthetic material for the enhanced systemic IVT mRNA delivery.

Investigation of the temperature responsive behaviors of novel polyaspartamide derivatives bearing alkyl ether-type pendants

Previous works reported that some temperature responsive polyaspartamide derivatives exhibited pH responsiveness, although pH responsive functional groups or pH-cleavable linkages were not introduced during the preparing process, which may be related to the hydroxyl groups of their pendant alkanolamide moieties. In order to investigate whether pH will also affect the temperature responsive behavior of temperature responsive polyaspartamide derivatives without hydroxyl groups, four linear alkyl ether-type amine compounds with one ether oxygen atom and 3 to 6 carbon atoms, denoted as OCx (x represents the number of carbon atoms in alkyl ether-type amine compounds), were selected for the aminolysis reaction of poly(succinimide) to design and synthesize the polyaspartamide derivatives bearing alkyl ether pendants, named PASP-OCx. The chemical structures and molecular weights of the obtained polymers were characterized and confirmed by FTIR, 1 H NMR and SEC-MALLS. The water-solubilities, surface tensions and transmittances of PASP-OCx aqueous solutions were also investigated. Results showed that PASP-OCx can be dissolved in deionized water when x is less than or equal to 5. The surface tensions of PASP-OC4 and PASP-OC5 solutions exhibited obvious turning points. Interestingly, transmittances results showed that PASP-OC5 exhibited temperature responsive behaviors under acidic, neutral or alkaline conditions (pH ≤ 10.0); PASP-OC4 only exhibited temperature responsive behaviors under acidic condition (pH ≤ 3.0); while PASP-OC3 did not exhibit temperature responsive behavior. The LCST value of PASP-OC5 and PASP-OC4 can be turned by adjusting the pH value of their solutions, and decreases with decreasing the pH value. Additionally, the influence of pH on the LCST values of PASP-OC4 and PASP-OC5 was investigated by zeta potential, and the results showed that the decrease of LCST values may be due to the reducing of electrostatic repulsion with pH decreasing. Therefore, results showed that pH can also affect the temperature responsive behavior of temperature-responsive polyaspartamide derivatives that do not contain hydroxyl groups.

Dual‐crosslinked hydrogels with metal coordination from novel co‐polyaspartamide containing 1,2‐dihydroxy and imidazole pendant groups

AbstractHerein, a series of new polyaspartamide derivatives, PolyAspAm(API/APD)s, is prepared from polysuccinimide, which is the thermal polycondensation product of aspartic acid, via successive ring‐opening using 1‐(3‐aminopropyl)imidazole (API) and 3‐amino‐1,2‐propanediol (APD). Metal‐coordinated hydrogels are generated by adding divalent metal ions (Cu2+, Zn2+) to the aqueous polymer solution. The resulting gels can adhere strongly to various substrates. Further, novel dual‐crosslinked hydrogels are prepared, where the first network is generated via acetal formation between the massive 1,2‐hydroxyl groups of the polymer and glutaldehyde as the crosslinker. Subsequent immersion of the product gel in various metal ion‐containing solutions forms a second network via metal coordination, thereby affording mechanically robust hydrogels. Multiple metal‐coordination interactions are expected to occur between the imidazole functional groups and metal cations. The mechanical properties of resulting gel vary depending on the metallic species. These novel kinds of hydrogels are expected to find biomedical applications as adhesives and antibacterial soft matter.

Nucleic Acid Delivery across Biological Barriers

One of the current critical issues in nucleic acid delivery is the efficient mRNA delivery into target cells, directed toward clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genome editing. To this end, we have developed a variety of cationic polyaspartamide derivatives with varying side chain structures because they can form nanocomplexes, termed polyplexes, with mRNA through electrostatic interactions. Interestingly, the delivery functions were highly affected by the chemical structures of the polyaspartamide side chains. Therefore, we review our previous research and provide a rationale for designing polypeptides for mRNA delivery.

Bone targeting nano-aggregates prepared from self-assembled polyaspartamide graft copolymers for pH sensitive DOX delivery.

Nanoparticles with bone targeting ability and pH-sensitivity were prepared with polyaspartamide (PASPAM) derivatives based on polysuccinimide (PSI) grafted with octadecylamine (C18), hydrazine (HYD) and polyethylene glycol (PEG, Mw: 5000). For the bone targeting, alendronate (ALN), which has bone affinity, was grafted to PEG and doxorubicin (DOX) was conjugated with linkers of acid sensitive hydrazone bonds, which can be cleaved most effectively in an intracellular acidic environment. At pH 5.0, ∼75% of the drug was released from ALN-PEG/C18/HYD-DOX-g-PASPAM due to the effective cleavage of HYD under the acidic condition. Also, ALN-PEG/C18/HYD-DOX-g-PASPAM particles were more effectively adsorbed on the surface of bone than PEG/C18/HYD-DOX-g-PASPAM. According to an in vivo antitumor activity test, the volume of tumor treated with ALN-PEG/C18/HYD-DOX-g-PASPAM decreased (1550 mm3) when compared with the PBS control sample (3850 mm3), proving that ALN-PEG/C18/HYD-DOX-g-PASPAM is an effective drug delivery system for the treatment of bone metastasis of breast cancer.

Synthesis and characterization of novel multi-hydroxy polyaspartamide derivative and its crosslinked hydrogels

In this study, a new type of multihydroxy synthetic polymer and its crosslinked gels were prepared. Poly(N-2,3-dihydroxypropyl aspartamide) (PDHPA), a poly(amino acid) composed of a peptide backbone and pendent 1,2-dihydroxy functional groups, was synthesized from polysuccinimide, the precursor polymer, by aminolysis reaction using 3-amino-1,2-propanediol. This polyaspartamide derivative exhibited several valuable properties including biodegradability, high water solubility, excellent biocompatibility, and good adhesion. Because of its unique chemical structure, PDHPA could serve as a useful platform for combination with other materials and preparation of dynamically reversible and self-healing crosslinked hydrogels. PDHPA was reacted with boric acid (H3BO3) to produce a transparent, dynamically reversible, and self-healing hydrogel, whose viscoelastic behavior depended on the chemical composition, water content, and pH condition. Moreover, PDHPA and the crosslinked gel exhibited relatively strong adhesion toward various types of substrates including glass, paper, metal, and plastic. Another hydrogel was prepared using PDHPA and glutaraldehyde in the presence of an acid catalyst; this hydrogel exhibited relatively high gel strength and swelling ratios in the range of 2–5. This new class of hydrophilic water-soluble polymer and its crosslinked gels with excellent hydrolytic degradability, adhesive property, non-cytotoxicity, and biocompatibility have application potential in various biomedical fields.

Fine-Tuning of Hydrophobicity in Amphiphilic Polyaspartamide Derivatives for Rapid and Transient Expression of Messenger RNA Directed Toward Genome Engineering in Brain.

Rapid and transient expression of in vitro transcribed mRNA (IVT mRNA) in target cells is a current major challenge in genome engineering therapy. To improve mRNA delivery efficiency, a series of amphiphilic polyaspartamide derivatives were synthesized to contain various hydrophobic moieties with cationic diethylenetriamine (DET) moieties in the side chain and systematically compared as mRNA delivery vehicles (or mRNA-loaded polyplexes). The obtained results demonstrated that the side chain structures of polyaspartamide derivatives were critical for the mRNA delivery efficiency of polyplexes. Interestingly, when the mRNA delivery efficiencies (or the luciferase expression levels in cultured cells) were plotted against an octanol–water partition coefficient (log P) as an indicator of hydrophobicity, a log P threshold was clearly observed to obtain high levels of mRNA expression. Indeed, 3.5 orders of magnitude difference in the expression level is observed between −2.45 and −2.31 in log P. This threshold of log P for the mRNA transfection efficiency apparently correlated with those for the polyplex stability and cellular uptake efficiency. Among the polyaspartamide derivatives with log P > −2.31, a polyaspartamide derivative with 11 residues of 2-cyclohexylethyl (CHE) moieties and 15 residues of DET moieties in the side chains elicited the highest mRNA expression in cultured cells. The optimized polyplex further accomplished highly efficient, rapid, and transient IVT mRNA expression in mouse brain after intracerebroventricular and intrathecal injection. Ultimately, the polyplex allowed for the highly efficient target gene deletion via the expression of Streptococcus pyogenes Cas9 nuclease-coding IVT mRNA in the ependymal layer of ventricles in a reporter mouse model. These results demonstrate the utility of log P driven polymer design for in vivo IVT mRNA delivery.

Biodegradable Supramolecular Materials Based on Cationic Polyaspartamides and Pillar[5]arene for Targeting Gram‐Positive Bacteria and Mitigating Antimicrobial Resistance

AbstractThe increasing number of infections caused by pathogenic bacteria has severely affected human society, for instance, numerous deaths are from Gram‐positive methicillin‐resistant Staphylococcus aureus (MRSA) each year. In this work, four biodegradable antibacterial polymer materials based on cationic polyaspartamide derivatives with different lengths of side chains are synthesized through the ring‐opening polymerization of β‐benzyl‐l‐aspartate N‐carboxy anhydride, followed by an aminolysis reaction and subsequent methylation reaction. The cationic quaternary ammonium groups contribute to the insertion of the catiomers into the negatively charged bacterial membranes, which leads to membranolysis, the leakage of bacterial content, and the death of pathogens. Except for wiping out MRSA readily, the biodegradable polymers possessing alterable antibacterial potency can minimize the possibility of microbial resistance and mitigate drug accumulation by virtue of their cleavable backbone. To manipulate the poor biocompatibility of these polycations, carboxylatopillar[5]arene (CP[5]A) is introduced to the polymeric antibacterial catiomers through the supramolecular host–guest approach to obtain novel antibacterial materials with pH‐sensitive characteristics (with CP[5]A departure from cationic quaternary ammonium compounds under acid conditions) and selective targeting of Gram‐positive bacteria. Finally, the facile and robust antibacterial system is successfully applied to in vivo MRSA‐infected wound healing, providing a significant reference for the construction of advanced antibacterial biomaterials.

Temperature Responsive Nanoparticles Based on PEGylated Polyaspartamide Derivatives for Drug Delivery.

The temperature responsive PEGylated polyaspartamide derivative, denoted as mPEG-PAAHP, was synthesized by the click reaction. FTIR and 1H NMR were adopted to characterize and confirm the chemical structures of the obtained mPEG-PAAHPs. The temperature responsive behavior investigated by transmittance and dynamic light scattering showed that some of the obtained mPEG-PAAHPs exhibited obvious temperature responsiveness and could be used to prepare nanoparticles by quickly heating. Drug paclitaxel can be encapsulated into mPEG-PAAHP based nanoparticles with a high encapsulation efficiency up to 99% (corresponding to a drug loading content of around 9.9%). Dynamic light scattering results showed that the PTX-loaded nanoparticles had a mean size around 80 nm (PDI<0.2) and good stability in PBS with 150 mM ionic strength. In vitro cytotoxicity results showed that mPEG-PAAHP did not show any toxicity to HeLa cells, but the PTX-loaded nanoparticles based on mPEG-PAAHP exhibited obvious anti-cancer activity. Thus, the temperature responsive PEGylated polyaspartamide derivative mPEG-PAAHP may be a promising drug delivery system.

Tunable nonenzymatic degradability of N-substituted polyaspartamide main chain by amine protonation and alkyl spacer length in side chains for enhanced messenger RNA transfection efficiency

ABSTRACT Degradability of polycations under physiological conditions is an attractive feature for their use in biomedical applications, such as the delivery of nucleic acids. This study aims to design polycations with tunable nonenzymatic degradability. A series of cationic N-substituted polyaspartamides were prepared to possess primary amine via various lengths of alkyl spacers in side chains. The degradation rate of each polyaspartamide derivative was determined by size exclusion chromatography under different pH conditions. The N-substituted polyaspartamide containing a 2-aminoethyl moiety in the side chain (PAsp(AE)) showed considerable degradability under physiological conditions (pH 7.4, 37 °C). In contrast, the N-substituted polyaspartamides bearing a longer alkyl spacer in the side chain, i.e. the 3-aminopropyl (PAsp(AP)) and 4-aminobutyl moieties (PAsp(AB)), more strongly suppressed degradation. Further, a positive correlation was observed between the degradation rate of N-substituted polyaspartamides and a deprotonation degree of primary amines in their side chains. Therefore, we conclude that the deprotonated primary amine in the side chain of N-substituted polyaspartamides can induce the degradation of the main chain through the activation of amide nitrogen in the side chain. When N-substituted polyaspartamides were utilized as a messenger RNA (mRNA) delivery vehicle via formation of polyion complexes (PICs), degradable PAsp(AE) elicited significantly higher mRNA expression efficiency in cultured cells compared to PAsp(AP) and PAsp(AB). The higher efficiency of PAsp(AE) might be due to the facilitated destabilization of PICs within the cells, directed toward mRNA release. Additionally, degradation of PAsp(AE) considerably reduced its cytotoxicity. Thus, our study highlights a useful design of well-defined cationic poly(amino acid)s with tunable nonenzymatic degradability.

Self-Assembly of siRNA/PEG- b-Catiomer at Integer Molar Ratio into 100 nm-Sized Vesicular Polyion Complexes (siRNAsomes) for RNAi and Codelivery of Cargo Macromolecules.

Vesicular polyion complexes (PICs) were fabricated through self-assembly of rigid cylindrical molecules, small interfering RNAs (siRNAs), with flexible block catiomers of poly(ethylene glycol) (2 kDa) and cationic polyaspartamide derivative (70 units) bearing a 5-aminopentyl side chain. 100 nm-sized siRNA-assembled vesicular PICs, termed siRNAsomes, were fabricated in specific mixing ranges between siRNA and block catiomer. The siRNAsome membrane was revealed to consist of PIC units fulfilling a simple molar ratio (1:2 or 2:3) of block catiomer and siRNA. These ratios correspond to the minimal integer molar ratio to maximally compensate the charge imbalance of PIC, because the numbers of charges per block catiomer and siRNA are +70 and -40, respectively. Accordingly, the ζ-potentials of siRNAsomes prepared at 1:2 and 2:3 were negative and positive, respectively. Cross-section transmission electron microscopic observation clarified that the membrane thicknesses of 1:2 and 2:3 siRNAsomes were 11.0 and 17.2 nm, respectively. Considering that a calculated long-axial length of siRNA is 5.9 nm, these thickness values correspond to the membrane models of two (11.8 nm) and three (17.7 nm) tandemly aligned siRNAs associating with one and two block catiomers, respectively. For biological application, siRNAsomes were stabilized through membrane-cross-linking with glutaraldehyde. The positively charged and cross-linked siRNAsome facilitated siRNA internalization into cultured cancer cells, eliciting significant gene silencing with negligible cytotoxicity. The siRNAsome stably encapsulated dextran as a model cargo macromolecule in the cavity by simple vortex mixing. Confocal laser scanning microscopic observation displayed that both of the payloads were internalized together into cultured cells. These results demonstrate the potential of siRNAsomes as a versatile platform for codelivery of siRNA with other cargo macromolecules.

Adhesive, self-healing and antibacterial properties of Cu-coordinated soft gel based on histamine-conjugated polyaspartamide

Metal-ligand coordination bonding is a non-covalent interaction that has been extensively studied as an effective way to improve the mechanical properties of hydrogels or to generate novel supramolecular self-healing gels. In this study, biodegradable polyaspartamide derivatives conjugated with histamine were synthesized and used to prepare the metal-coordinated supramolecular gel with several different metal-ions such as Cu(II), Ni(II), and Zn(II) in an aqueous solution. The resulting gels showed high adhesive properties on glass and plastics substrates, and the adhesive strength could be modulated by using different metal-ion species as well as the concentration and medium pH. In particular, the Cu(II)-coordinated gel exhibited a reversible self-healing behavior and good antibacterial activity. These wholly bio-based supramolecular polymer gels have potential for various biomedical applications with their multifunctional properties comprising adhesive, self-healing and antimicrobial properties in wet gel state.

Corrosion protection of waterborne epoxy coatings containing mussel-inspired adhesive polymers based on polyaspartamide derivatives on carbon steel

A novel mussel-inspired adhesive polymer (PHEA-DOPA) containing the 3,4-dihydroxyphenylalanine (DOPA) functional group based on polyaspartamide derivatives was synthesized. The corrosion protection of the waterborne epoxy coatings containing the adhesive polymers was investigated by electrochemical impedance spectroscopy (EIS). The results indicated that the PHEA-DOPA could improve the corrosion resistance of the waterborne epoxy coating. The corrosion products were also analyzed by Raman microspectroscopy (RM), indicating the formation of the insoluble DOPA-Fe complexes on the carbon steel surface. These complexes simultaneously acting as a passivating layer, can inhibit the process of corrosion at the metal-solution interface. The differential scanning calorimeter (DSC) measurement indicated that PHEA-DOPA can increase the crosslinking density of coating. The effect of O2 on the protective mechanism of the PHEA-DOPA coating in a 3.5% NaCl solution was also evaluated by EIS. The results indicated that the barrier effect was significantly improved under aerated conditions because DOPA was oxidized to DOPA–quinone (Dq) by O2, which triggered the reaction with Fe ions that were released from the surface of the carbon steel. This led to more compact coatings.

Hydrophobicity‐enhanced adhesion of novel biomimetic biocompatible polyaspartamide derivative glues

AbstractThe development of wet bioadhesives for tissue fixation and wound care remains a challenge. While various commercial bioadhesive products based on both natural and synthetic materials are available, both types of adhesive have several drawbacks including weak adhesion or toxicity. In this study, we present a novel mussel‐inspired synthetic adhesive based on polyaspartamide derivatives modified with dopamine and a series of hydrophobic n‐alkylamines (lauryl, octyl, hexyl and butyl), which shows very strong adhesion toward various types of substrates such as paper, glass and metals as well as several common plastics (0.1–0.6 MPa). Additionally, the effect of adding metal ions (Mg2+, Ca2+) as a coordination crosslinker to enhance adhesion performance was investigated using acryl plastic substrate. Even under deionized water conditions, the strong adhesion was found to be maintained for an appreciably long time after 24 h. This novel and biocompatible polymer glue system has potential in various applications including as a medical tissue adhesive and sealant. © 2018 Society of Chemical Industry

Polyaspartamide-based graft copolymers encapsulating iron oxide nanoparticles for imaging and fluorescence labelling of immune cells.

Iron oxide nanoparticles (NPs) were encapsulated with polyaspartamide-based graft copolymers to bind and track the immune cells as imaging probes. Mono-disperse iron oxide NPs with a mean diameter of 10.7 nm were synthesized by the thermal decomposition method, and their shape and distribution were measured by electrophoretic light scattering and transmission electron microscopy. To enhance their biocompatibility, interfacial and hydrodynamic stability, and fluorescence detection, biodegradable polysuccinimide (PSI) grafted with several functional groups of octadecylamine (C18), ethanolamine (EA), ethylenediamine (EDA), 4-(N-maleimidomethyl) cyclohexane carboxylic acid N-hydroxysuccinimide ester (SMCC), and fluorescein isothiocyanate (FITC) was coated on the iron oxide NPs. The structure of the C18/EA/SMCC/FITC-g-PSI copolymer was confirmed using 1H-NMR and FTIR spectroscopy, and its cell binding ability was investigated by flow cytometry and confocal laser scanning microscopy. The synthesized C18/EA/SMCC/FITC-g-PSI copolymer showed an excellent binding affinity to CD4+ T cells, and was highly biocompatible as the cell viability at the highest polymer concentration of 0.4 mg mL-1 was greater than 85 and 75% after 24 and 48 h, respectively, from MTT assay.

Synthesis and Application of Polyaspartamide Derivatives for Drug/Gene Delivery

Synthesis and Application of Polyaspartamide Derivatives for Drug/Gene Delivery