ACS Applied Bio Materials最新文献

N-Heterocyclic carbene (NHC) complexes are known to have antibacterial properties in solutions. However, these complexes have never been immobilized on solid supports to prepare antibacterial surfaces. Here, we tackled this lack and succeeded in immobilizing these NHC complexes on gold surfaces by electropolymerization. For this, we synthesized a series of various NHC complexes of different low-valent transition metals (M = Ag(I), Au(I), Rh(I), Ru(II), Cu(I)) bearing a pyrrole function at the five-membered carbenic cycle. We measured the antibacterial properties of these complexes against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two Gram-positive bacteria (Staphylococcus aureus and Listeria innocua) by determining their minimum inhibitory concentration (MIC) values. All NHC complexes presented interesting antibacterial properties that are metal-dependent. The silver-NHC complex showed higher antibacterial activity against Gram-negative bacteria (MIC = 16 μg·mL^-1) than against Gram-positive bacteria (MIC = 32 μg·mL^-1) and was poorly efficient against L. innocua. All other metal-NHC complexes were more efficient against Gram-positive bacteria, with MIC values in the range 4-16 μg·mL^-1. These NHC complexes were then electropolymerized on gold substrates using their pyrrole function. Efficient incorporation of these NHC species into polypyrrole (PPy) films was confirmed by X-ray photoelectron spectroscopy (XPS) measurements with metal contents ranging from 0.8% (Cu) to 12.3% (Ag). Scanning electron microscopy (SEM) and profilometry measurements ascertain that the homogeneity, structure, and thickness of the films depend on the metal. The antibacterial activities of the polypyrrole films were then determined by the halo inhibition method. A very good match between the antibacterial properties of the films and those of the monomers with Ag(I), Au(I), and Rh(I) complexes was found. For the other complexes, the metallic content was too low to obtain interesting antibacterial properties. The cytotoxicity of the films was finally evaluated on normal human dermal fibroblasts (NHDF). Our study reveals a strong impact of the doping anions of polypyrrole on cell viability.

An overarching limitation of therapeutic biologics is the limited half-life these proteins often exhibit once in circulation. PEGylation, the chemical conjugation of proteins to poly(ethylene glycol) (PEG), is a common strategy to improve protein pharmacokinetics (PK) by enhancing stability, reducing immunogenicity, and decreasing renal clearance. Tissue Inhibitor of Metalloproteinases 2 (TIMP2) is a 22 kDa matrisome protein that exhibits therapeutic potential across a range of human disease models yet possesses a short serum half-life. To advance the therapeutic development of recombinant His-tagged TIMP2 (TIMP2), we utilized primary amine conjugation (1 kDa) and site-specific histidine conjugation (10 kDa) to improve its circulating half-life. Primary amine conjugation of PEG molecules to TIMP2 (TIMP2-a-PEG(_n)) is efficient, yet it produces multiple positional isomers that are difficult to purify. Furthermore, high levels of conjugation can affect the MMP-inhibitory activity of TIMP2. Despite this, TIMP2-a-PEG(_n) displays a significant improvement (11.5-fold) in serum half-life versus unconjugated TIMP2. In contrast, site-specific histidine conjugation targets the histidine tag, enabling the purification of mono-PEGylated (TIMP2-H-PEG₍₁₎) and di-PEGylated (TIMP2-H-PEG₍₂₎) forms. Our findings demonstrate that TIMP2-H-PEG₍₁₎ exhibits improved PK with enhanced stability and a 6.2-fold increase in circulating half-life while maintaining MMP-inhibitory activity. These results suggest that site-specific PEGylation at a C-terminal His₆ tag is a promising approach for further preclinical development of TIMP2 as a therapeutic biologic.

This research aimed to evaluate the potency of preparation based on heparinized iron oxide nanoparticles (hIONPs) in combination with radiation therapy, including magnetic delivery via the applied magnetic field (AMF), in sarcoma and cervical cancer models. For in vitro studies, cells of rhabdomyosarcoma (RD), fibrosarcoma (HT1080), and cervical cancer (HeLa S3) were treated with hIONPs and analyzed for survival rate and hIONP uptake. Then, cell morphology, cell cycle, increase of reactive oxygen species, mitochondria depolarization, and ability to form colonies were assessed for combined treatment (hIONPs + 3Gy). For in vivo research, hIONPs were administered once in the hybrids of CBAxC57Bl/6j mice, grafted with sarcoma (S37) and cervical cancer (CC5) strains. The ultimate in vivo treatment modes were: (1) i.v. hIONPs (14 μg/kg) + 5 Gy; (2) i.v. hIONPs (14 μg/kg) + AMF + 5 Gy; and (3) i.t. hIONPs (2,8 μg/kg) + 5 Gy. The overall survival rates, increase in life expectancy, inhibition of tumor growth (tumor growth inhibition), and degree of inhibition (T/C) were determined, and pathomorphological changes were assessed in experimental groups. The combined treatment in vitro (hIONPs + 3Gy) promotes multiple tumor cell death with high-severity peroxide effects compared with other groups. The sarcoma cells were more sensitive than cervical cancer cells. For in vivo, an enhancing effect was revealed by the combination of radiotherapy and magnetic-delivered hIONPs. For S37 tumor, the treatment regimen was characterized as having a high antitumor effect, ≪++++ ≫, with a 20% cure rate of mice. For the CC5 tumor, the effect was accompanied by the inhibition of tumor growth, an increase in the life expectancy of animals, and was characterized as a significant antitumor effect, ≪+++/++ ≫. From the data obtained, it can be concluded that the radiosensitizing potential of hIONPs may be taken as a basis of combined radiation treatment protocols.

Global plastic production is increasing yearly, with packaging materials and disposable plastics accounting for a sizable portion of the total. Despite its apparent advantages, the resulting plastic waste accumulates in landfills and oceans, causing severe environmental and public health issues. Shifting from conventional plastics to biodegradable plastics (BPs) is increasingly being proposed as an efficient management of end-of-life plastics. While several BPs such as poly(lactic acid), poly(ε-caprolactone), and poly(hydroxyalkanoates) have been widely used, their biodegradation rates often do not meet the anticipated level under home-compost or other certain environments (e.g., soil, marine). Recently, enzyme-embedded BPs have emerged as an outstanding alternative to currently used synthetic plastics. It achieves rapid degradation and compostability by introducing a specific enzyme into the biodegradable polymer. In this context, this review aims to summarize the recent advances in the development of such superior biomaterials. It identifies and prioritizes the critical success factors required for the production of enzyme-embedded BPs. The review also discusses several challenges in the development and application of these innovative polymer materials.

Ultrasound molecular imaging (USMI) utilizing targeted microbubbles (tMBs) and primary acoustic radiation force (F_rad) pulses has demonstrated enhanced sensitivity in recent studies. However, current USMI techniques are limited to a single ligand-receptor pair per imaging scan. With the advent of the buried-ligand architecture (BLA), "cloaked" ligand-receptor binding and tMB adhesion can be activated by F_rad pulses, enabling multicolor USMI. This approach permits the selective activation of two or more tMB species, each binding to its cognate receptors based on distinct resonance frequencies (f₀) tuned by F_rad pulses. The goal of this study was to demonstrate frequency-selective tMB adhesion to receptor-bearing microvessel tubes in vitro. Size-isolated BLA tMBs of 1 and 5 μm diameter were synthesized with f₀ equal to 7 and 4 MHz, respectively (within the frequency limits of our ultrasound probe). The 1 μm tMBs were conjugated with IELLQAR peptide for P-selectin targeting, while the 5 μm tMBs were conjugated with cyclo-RGD peptide for α_vβ₃ integrin targeting. The MB gas volume fraction (φ_MB) was used to unify size and concentration into a single parameter. Frequency-selective tMB binding was quantified using fluorescence microscopy. Specific targeting was evaluated by comparing RGD- or IELLQAR-MB attachment to control RAD- or nonligand-bearing MBs, respectively. The results confirmed specific frequency-selective targeting of the two tMB species to their cognate receptors when activated by F_rad pulses at their respective f₀, both individually and in a cocktail. In the cocktail population, φ_MB of RGD-MB targeting increased 18-fold at 4 MHz compared to 7 MHz, while IELLQAR-MB targeting φ_MB increased 5-fold at 7 MHz compared to 4 MHz. In conclusion, this study presents the first demonstration of frequency-selective targeting of two different receptor species by two different tMB species, representing a significant step toward multicolor USMI and the potential for simultaneous imaging of multiple biomarkers in vivo within a single scan.

The surgical repair of hernias, a prevalent condition affecting millions worldwide, has traditionally relied on polypropylene (PP) mesh due to its favorable mechanical properties and biocompatibility. However, postoperative infections remain a significant complication, underscoring the need for the development of infection-resistant hernia meshes. This study provides a comprehensive analysis of current advancements and innovative strategies aimed at enhancing the infection resistance of PP mesh. It presents an overview of various research efforts focused on the integration of antimicrobial agents, surface modifications, and the development of bioactive coatings to prevent bacterial colonization and biofilm formation. Additionally, the synergistic effects of novel material designs and the role of nanotechnology in optimizing the anti-infective properties of PP mesh are explored. Recent clinical outcomes and in vitro studies are critically examined, highlighting challenges and potential future directions in the development of next-generation hernia meshes. Emphasis is placed on the importance of interdisciplinary approaches in advancing surgical materials with the ultimate goal of improving patient outcomes in hernia repair.

Silk sericin (SS), a biocompatible protein derived from silkworms, exhibits valuable properties for medicinal applications, including antioxidant activity and cell growth support. However, their rapid degradation limits their practical use. This study introduces silver ions (Ag⁺) as a dual-function cross-linking agent to enhance the structural and functional properties of SS-based hydrogels. The incorporation of Ag⁺ stabilized the hydrogel network through dityrosine cross-links and coordination bonds with SS amino acid side chains, significantly improving hydrolytic and enzymatic resistance. Hydrogels cross-linked with 1 mM Ag⁺ demonstrated optimal performance, retaining excellent structural integrity while preserving the cytocompatibility and antioxidant activity of SS. These hydrogels also exhibited broad-spectrum antimicrobial activity against bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant S. aureus), fungus (Aspergillus niger), and yeast (Candida albicans). Higher Ag⁺ concentrations, however, increased the cytotoxicity without enhancing the antimicrobial efficacy. This study highlights the potential of Ag⁺ cross-linked SS-based hydrogels as scalable, multifunctional 3D structures for antimicrobial applications.

Three-dimensional (3D) culture of cells has gained increasing popularity because of its enhanced physiological relevance and more accurate representation of in vivo tissues. Matrigel, alginate, hyaluronic acid, and collagen are biocompatible 3D culture platforms with cell biofunctions, while it is difficult to decouple the biofunctions with mechanical properties. Polyacrylamide (PAAm) is a biocompatible but biologically nonfunctional platform heavily used in 2D culture. However, the cytotoxicity of acrylamide (AAm) prevents the application of PAAm as a platform for the 3D culture. Here, through RAFT copolymerization of AAm with a primary amine-bearing functional monomer, followed by postpolymerization modification, we synthesized nontoxic, linear PAAm featuring either multithiol or multinorbornene groups, available in various chain lengths. PAAm networks were fabricated by photoinduced thiol-norbornene coupling. The resulting PAAm hydrogel was biocompatible and structurally homogeneous with highly tunable and reproducible mechanical properties. PAAm hydrogels supported the 3D culture of human umbilical vein endothelial cells (HUVECs), where a higher adhesive ligand density promoted the viability of HUVECs. Furthermore, in combination with Matrigel, the PAAm hydrogel was used in the 3D culture of intestinal organoids, demonstrating that a lower mechanical strength was favorable. In summary, this report paves the way for the use of PAAm hydrogels in 3D culture, which is especially appealing for the decoupling of biological functions and mechanical properties.

Although numerous technical advances have been made in cancer treatment, chemotherapy is still a viable treatment option. However, it is more effective when used in combination with photothermal therapy for resistant breast cancer cells. This study introduces a smart drug delivery system, (DOX-OA+VERA+AuNRs)@NLC, which is designed for dual chemo/photothermal therapy of multiple-drug-resistant breast cancer. Type-III nanostructured lipid carriers (NLCs) were used as drug delivery systems, where nano-in-nano structures offer several advantages. Doxorubicin (DOX) was used as the antitumor agent by ion-pairing it with oleic acid (OA) to increase the DOX loading capacity, as well as to reduce the burst release of the drug. Verapamil (VERA), which was used as a chemosensitizer to overcome the multiple-drug resistance, was co-loaded with DOX-OA. Gold nanorods (AuNRs) were exploited as the photothermal therapy agent in photothermal therapy (PTT) application, which would have a synergistic relation with chemotherapy. The release of DOX-OA and VERA from NLCs was studied in vitro by triggering with NIR laser irradiation. Thus, an all-in-one drug delivery system was designed to release the active pharmaceutical ingredients (APIs) at higher concentrations in the desired region and provide both chemo/PTT. Besides, the application of a folic acid-chitosan (FA-CS) coating to NLCs has facilitated the development of systems capable of targeting and specifically releasing their cargo within cancerous tissues while preserving their surrounding environment.