Low Hemolysis Rate Research Articles

Antibacterial activity of guanidinium-based ionic covalent organic framework anchoring Ag nanoparticles

In this paper, the antibacterial 2D covalent organic framework (COFTGTp) containing guanidyl cation was synthesized and used as a carrier to deposit AgNPs on N and O groups to form nanocomposites to avoid AgNPs aggregation and achieve excellent antibacterial effect. The Ag content in Ag/COFTGTp was 10.3% determined by ICP. TEM can clearly observe that AgNPs were uniformly dispersed in COFTGTp. Ag/COFTGTp was stable after being evenly dispersed in water with low cytotoxicity and hemolysis rate to erythrocytes. In bacteriostatic study, the minimum inhibitory concentration of Ag/COFTGTp for E. coli and S. aureus were 100 μg/mL and 50 μg/mL, respectively. Finally, the morphology of the bacteria was observed by SEM, confirmed the main sterilization by Ag/COFTGTp was destroying the cell wall of the bacteria.

Mg-Fe LDH sealed PEO coating on magnesium for biodegradation control, antibacteria and osteogenesis

l Mg-Fe LDH films were fabricated on PEO treated Mg by transforming FeOOH. l Mg-Fe LDH films could enhance the corrosion resistance of Mg. l Mg-Fe LDH films exhibit good photothermal antibacterial and osteogenesis activity. l Animal experiments showed Mg-Fe LDH films show good histocompatibility in vivo . Attempt of developing bio-safety and functional layered double hydroxides (LDHs) modified plasma electrolytic oxidation (PEO) coatings, has become a hotspot in the protection of magnesium (Mg) based biomedical implants. In the present work, Mg-Fe LDH films with different Fe contents were fabricated on PEO coating via a novel two-step method: firstly, the FeOOH films were prepared by immersing PEO sample in Fe 2+ -containing solution, and then Mg-Fe LDH films were formed by transforming the FeOOH films via a hydrothermal treatment in water. The highly-oriented LDH nano-sheets could enhance the anti-corrosion performance of PEO coating, which was proved by the results of electrochemical test, hydrogen evolution and corroded morphology. PEO/Mg-Fe LDH coatings showed a low hemolysis rate (less 5%) than PEO coating. In addition, PEO/Mg-Fe LDH coatings were more favorable for cell adhesion and proliferation than PEO coating. Moreover, PEO/Mg-Fe LDH coatings showed good photothermal conversion property, which demonstrated the excellent rapid antibacterial effect under NIR light. In vitro culture of rat bone marrow stem cell (rBMSC) suggested that cells cultured in the extract of PEO/Mg-Fe LDH coatings had a better osteogenic activity. In vivo subcutaneous implantation test revealed that PEO/Mg-Fe LDH coatings exhibited good anti-corrosion and histocompatibility.

Impact of an engineered micro-patterned interface on chitosan/glycerol membranes for wound healing

Biomimetic materials are of great significance in wide applications. As a bioactive polysaccharide, chitosan (CS) has attracted much attention in multiple fields. Inspired by the natural shark skin interface, herein, we proposed a methodology to obtain serial biomimetic CS/glycerol membranes via a facile mold casting and solvent evaporation process under mild aqueous conditions. The surface morphology, chemical structures, and physical characteristics of the developed membranes were determined by scanning electron microscopy, Fourier transformed infrared spectroscopy, tensile measurement, water vapor transmission rate, liquid uptake behavior, solubility, and dynamic water contact angle tests. Furthermore, in vitro and in vivo biological assays were performed, including antibacterial ability, hemostatic performance, hemolytic reaction, cytotoxicity evaluation, and contaminated wound healing assessment. Compared with the flat membranes, the micro-patterned CS/glycerol membranes show the higher water-absorbing ability (up to ca. 26-fold@30 min), moderate tensile strength (8.5–14.7 MPa), superior bacteriostasis (84.9% to 98.6% against S. aureus, 84.3% to 99.6% against E. coli), decent hemostat efficacy (within 75.7 s), low hemolysis rates (less than 0.5%), and benign cytotoxicity (84.2% to 98.4% of viability), which favor promoting contaminated wound healing. Thus, the biomimetic micro-patterned membranes improve bioactive performance and show the merits of simple operation, low cost, and easy scale-up. All these properties indicate that the hybrid micro-patterned membrane could be used as a suitable candidate for dermal wound dressings and open up the insights for developing other bionic interfaces in future potential applications.

Polydopamine-heparin complex reinforced antithrombotic and antimicrobial activities of heparinized hydrogels for biomedical applications

Large-scale fabrication of heparinized hydrogel could be accomplished by free-radical crosslinking polymerization (FRCP), whilst its bioactivity is often partially lost. Heparinized hydrogel based implantable medical devices, therefore, frequently encounter the compelling problems of thrombosis and microbial infection. In this study, a facile FRCP approach was proposed to fabricate heparinized hydrogels by preforming polydopamine-heparin (PDA-HEP) complex, which bypassed the steps of heparin functionalization and effectively preserved the function of heparin in the meantime. Compared with heparin mixed hydrogels, heparin in PDA-HEP complex composite hydrogels augmented the antimicrobial activity of PDA by enhancing the combined bactericidal action of cations and reactive oxygen species (ROS), while still maintaining its anticoagulant function. Since its integration of extremely low hemolysis rate, remarkable anticoagulation property and efficient bactericidal performance, we believe that this universal method of preparing heparinized hydrogels based on PDA-HEP complex will speed up the versatile application of hydrogel implants in clinical medicine.

Biocidal organic-inorganic urethane-siloxane coating by facile polymerization of single component soy-based prepolymer

The present work has considered designing bioactive and biocidal coatings to address the unsatisfactory performance of implanted medical devices due to microbial contamination. The non-leaching biocidal polyurethane-siloxane coating was fabricated through the sol-gel reaction of monocomponent soybean oil prepolymer containing the reactive alkoxysilane, quaternary ammonium, and urethane moieties (Si-PPU) on a model metallic substrate. The Si-PPU prepolymer was prepared by three-step synthesis, including the carbonation of ESBO with CO 2 , urethane formation through the non-isocyanate approach, and simultaneous quaternization, and alkoxysilane functionalization. The adhesion strength of about 2.75 MPa to an aluminum plate, high pendulum hardness (254 s −1 ), superior flexibility, and high impact resistance could meet biomedical coating applications' requirements. The superior contact-active biocidal activity towards Gram-negative and Gram-positive bacteria was provided by prepared coating. Meanwhile, no evidence for cytotoxicity was observed, and the coating presented favorable cell adhesion and proliferation. The high cell viability (>90%) and low hemolysis rate (HR < 1%) confirmed the cytocompatibility of coatings. • Alkoxysilane, quaternary, and urethane functionalized soybean oil was synthesized. • Urethane-siloxane bio-based antibacterial coating was prepared by sol-gel process. • Promising bactericidal along with excellent biocompatibility was attained.

Self-assembly of nanomicelles with rationally designed multifunctional building blocks for synergistic chemo-photodynamic therapy.

Rationale: The combination of photosensitizers, oxygen supply agents, and adjuvant therapy drugs in a single nano-drug delivery system for photodynamic therapy (PDT) has been showing great promises to overcome the inherent challenges of PDT for tumor treatment. However, the complicated preparation of integrating multiple components hampers their further developments. Here, we describe a self-assembly nanomicelle with rationally designed building blocks, which shows a high efficiency of synergistic chemo-photodynamic therapy in the animal modal.Methods: The nanomicelle was prepared by a coordination-driven self-assembly based on a rationally designed ferrocene cyclopalladated compound coupled with photosensitizers and hyaluronic acid (referred to as FCP-Tph/HA). The morphology, targeting drug delivery, pharmacokinetics, hemolysis, and multimodal synergistic therapy of FCP-Tph/HA were investigated.Results: The formation of nanomicelles presents a low hemolysis rate and a prolonged blood circulation time. FCP-Tph/HA possesses an enhanced antitumor effect in vitro through the specific binding of HA to CD44 and combining chemotherapy with oxygen self-supplying PDT. Simultaneously, the nanomicelle facilitates a significantly improved antitumor efficacy (>90% tumor regression) on a breast cancer model in vivo.Conclusion: Our results present a modular self-assembled nanomicellar platform with synergistic chemo-photodynamic therapy for challenging PDT-based tumor treatment.

Hemoglobin-Inorganic Hybrid Nanoflowers with Different Metal Ions as Potential Oxygen Carrying Systems.

Protein-inorganic hybrid nanoflowers have tremendous potential in bionanotechnology due to their simple method of preparation, high stability and superior properties. Considering these features, the present study was designed to investigate the artificial blood substitution potentials of hemoglobin-inorganic hybrid nanoflowers. In this context, hemoglobin-inorganic hybrid nanoflowers (Cu-NF, Co-NF and Zn-NF) were synthesized using with different metal ions (copper, cobalt and zinc), then their oxygen carrying capacity, the hemolytic studies, in vitro oxidant/antioxidant capacity levels and oxidative stress index were reported for the first time. The present findings have revealed that Zn-NF had significant oxygen content and artificial oxygen carriers (AOC), as well as a significantly low percent hemolysis rate and a safe standard value. Also, hemolysis rate decreased along with the increases in hemoglobin content coupled with increments in nanoflower concentrations. The percentage hemolysis rate was lower than all nanoflowers at low free hemoglobin concentration, but hemolysis rates also increased with increments in concentration. The results showed that in general, Zn-NF stands out with its high total antioxidant capacity and low total oxidant capacity and oxidative stress index. The obtained results showed that Cu-NF and Co-NF, especially Zn-NF might be considered as a potential superior artificial oxygen carrier. Therefore, this nanoflower system might be act as an efficient material as a blood substitute in the near future.

A novel hydrogel based on Bletilla striata polysaccharide for rapid hemostasis: Synthesis, characterization and evaluation

The purpose of this study is to develop a new polysaccharide-based hydrogel. The Box-Behnken design was used to optimize the optimal synthesis conditions of the hydrogel, with the swelling parameters as indicators. The findings of rheologic tests confirm that free radical polymerization and the introduction of linear polymers improved the mechanical strength of the hydrogel. Combined with the characterization results, the gel mechanism of BSP-g-PAA/PVA DN hydrogel was proposed. The intermolecular association and entanglement increase, which effectively dissipates energy, thereby enhancing the mechanical properties of the hydrogel. In vitro blood compatibility experiments show that DN hydrogel has a low hemolysis rate and a good coagulation effect. The material is non-cytotoxic to L929 cells. The hepatic haemorrhage and mouse-tail amputation models of rats and mice were used to further evaluate the in vivo wound sealing and hemostatic properties of the hydrogel. The blood loss and hemostatic time were significantly lower than those of the control group, indicating that the hydrogel has excellent hemostatic effects. Therefore, the obtained BSP-g-PAA/PVA DN network hydrogel has good comprehensive properties and is expected to be used as a hemostatic material or a precursor of a drug carrier and a tissue engineering scaffold.

Favorable Antibacterial, Antibiofilm, Antiadhesion to Cells, and Biocompatible Polyurethane by Facile Surface Functionalization.

It is of paramount importance to prohibit biofilm formation in a wide range of implant devices, such as thermoplastic polyurethane (PU)-based catheters. It is possible only by means of a multifunctional material that provides fast and effective antibacterial activity, proper biocompatibility, and low bacterial and cell adhesion. In this paper, a facile chemistry approach has been developed to modify biomedical-grade PU with PU species, containing reactive uretdione functional groups for functionalization with the contact-type polyguanidine bactericidal agent and oxidized dextran as an antifouling polymer without sacrificing the thermal and mechanical properties. The resulting PU possesses broad-spectrum contact-active antibacterial activity against Gram-negative and Gram-positive bacteria with fast kinetics. The excellent antifouling capacity was confirmed by low nonspecific protein adsorption and reduced adhesion of fibroblast cells by ≥ 90%. In addition to antiadhesive and antibiofilm properties, high cell viability (>90%) and low hemolysis rate (HR < 1%) verified favorable cytocompatibility. Hence, the strategy followed to functionalize PUs in this paper might be considered to modify PU-based biomedical devices.

Cationic Glycopolymers with Aggregation-Induced Emission for the Killing, Imaging, and Detection of Bacteria.

Cationic glycopolymers with structures similar to those of typical poly(ionic liquid)s (PILs) were synthesized via the quaternization reaction of poly(4-vinyl pyridine) with halogen-functionalized d-mannose and tetraphenylethylene units. Such postpolymerization modification provided PILs with aggregation-induced emission effect as well as specific carbohydrate-protein recognition with lectins such as concanavalin A. The interactions between cationic glycopolymers and different microorganisms, including Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, were used for the killing, imaging, and detection of bacteria. Besides, these sugar-containing PILs showed a relatively low hemolysis rate due to the presence of saccharide units, which may have potential application in the field of biomaterials.

Biocompatible Platinum Nanoclusters Prepared Using Bitter Gourd Polysaccharide for Colorimetric Detection of Ascorbic Acid.

Ascorbic acid is an organic compound with antioxidant properties that can protect the human body from the threat of free radicals. Therefore, it is important to detect the existence and measure the concentration of ascorbic acid to regulate its content in the human body. In this work, we prepared bitter gourd polysaccharide (BGP)-stabilized platinum nanoclusters (Pt-BGP NCs) by reacting BGP with K2PtCl4. Pt-BGP NCs and catalyzed the decomposition of H2O2 to generate •OH radicals, which could oxidize TMB to form oxidized TMB (oxTMB), indicating their peroxidase-like properties. The kinetics followed the Michaelis–Menten equation. Furthermore, the colorimetric detection of ascorbic acid using Pt-BGP NCs showed high selectivity and a low detection limit of 0.191 μM. The accuracy of real sample detection using Pt-BGP NCs was as high as 98.9%. More importantly, Pt-BGP NCs had high cell biocompatibility and extremely low hemolysis rate due to the component of BGP. In summary, the prepared Pt-BGP NCs with reductive activity and good biocompatibility have good application prospects in colorimetric detection of ascorbic acid.

O-nitrobenzyl liposomes with dual-responsive release capabilities for drug delivery

To improve the therapeutic efficacy of anticancer drugs and reduce its toxic side effects, we synthesized a series of amphiphilic o-nitrobenzyl molecules 4-(4-N,N,N,N-dicarboxymethyl-diethylenetriamino)acetoxymethyl-3-nitro-N,N-dialk-ylbenzamide (N,N-NB-DTPA) with good photolysis property and acid sensitivity. Simultaneously, N, N-NB-DTPA liposomes composed of the o-nitrobenzyl molecules have good biocompatibility, low hemolysis rate and cytotoxicity, and the drug encapsulation efficiency of the liposomes exceeds 70%. N, N-NB-DTPA-DOX liposomes possess good stability and can keep uniform distribution in PBS solution for 10 days. The drug release rate of these drug-loaded liposomes reaches to the maximums under pH 5.0 and 30 min UV irradiation, revealing pH/UV dual-responsiveness of these drug-loaded liposomes. The low pH makes DOX separate from these drug-loaded liposomes, and the UV irradiation leads to o-nitrobenzyl ester bond cleave, which contribute to accelerate the release of drug from drug-loaded liposomes. Furthermore, N, N-NB-DTPA-DOX liposomes after UV irradiation have better therapeutic effect than single DOX·HCl, which may result from the production of nitrosobenzaldehyde derivatives after UV irradiation.

Polysaccharides-modified chitosan as improved and rapid hemostasis foam sponges

Serial hemostatic sponges consisting of polysaccharides-modified chitosan foam sponges were prepared by Schiff base crosslinking reaction between the deacetylated chitosan and oxidized dialdehyde cellulose. Such composite foam sponges were characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy to confirm their morphology and compositions. Then the coagulation process was evaluated in vitro by thrombus elasticity meters. Furthermore, the hemostasis experiments on mouse tail vein and rabbit femoral artery were also performed in vivo. The results strongly indicated that such synergistic cellulose-modified chitosan foam sponges showed comprehensively excellent water-absorbing quality, improved mechanical performance, low hemolysis rates, benign cytotoxicity, good resilience ability after repeated compression, and superior hemostasis capability both in vitro and in vivo. Furthermore, the hemostatic mechanism is via adhering/activating the red blood cell/platelet to form robust blood clots through the endogenous coagulation pathway, which serves as a good candidate for emergency trauma treatment in daily civilian and military hemostasis.

Preparation of Absorbable Suture Biomaterial Formed by Glycolide/Lactide and Its Application in the Congenital Thumb Deformity Surgery

Conducting polymers (CPs) can regulate cell behavior and promote the regeneration of damaged tissues, which are widely applied in tissue engineering. In this study, poly(3-hexylthiophene) (PHTP) was first obtained by the catalyst + transfer poly-condensation method, and then, it was mixed with poly(lactide-co-glycolide) (PLGA) to obtain a composite material with superconductivity (PHTP/PLGA). Besides, ferric chloride (FeCl3) was selected as the dopant, and the doping time was changed, so as to obtain 5 PHTP/PLGA materials with different conductivity (10-7 S/cm, 10-6 S/cm, 10-5 S/cm, 10-4 S/cm, and 10-3 S/cm). While PHTP/PLGA was physically characterized, the cell proliferation ability and blood compatibility of this series of materials were further analyzed, and the materials were made into medical sutures for the treatment of congenital thumb deformities. In the experiment, the surface morphology, hydrophilicity, and hydrophobicity of materials with different conductivity would not affect the difference in cell behavior. Using mouse embryonic osteoblasts (MC3T3-E1) as the research objects, increasing PHTP/PLGA conductivity could promote MC3T3-E1 alkaline phosphatase activity cell mineralization, and collagen type I expression. PHTP/PLGA series materials had a low hemolysis rate and were not easily affected by platelet adhesion and activation, meaning that they would not cause coagulation. The material was applied in the direct suture method of hammer deformity, and the results showed that the patient’s deformed thumb had a knot reaction and local skin edge necrosis. After dressing change, it gradually improved. Moreover, the excellent and good rate of deformed thumb based on this material was higher than that of wire extraction method and Kirschner wire fixation method (P &lt; 0.05).

In silico, in vitro and ex-vivo Toxicological Profiling of 5,7,4'-Trihydroxyflavone-8 -C-ß-Glucopyranoside - Vitexin

This study aimed to evaluate the in silico, in vitro, and ex-vivo toxicity of vitexin, the flavonoid 5,7,4'- trihydroxyflavone-8-C-β-glucopyranoside from Waltheria viscosissima. The chemical structure and predicted bioactive properties were also in silico analyzed. The in vitro and ex-vivo assays were performed according to the Ethics Code of the World Medical Association and were approved by the Ethics Committee of University Center of Patos (protocol number: 3.621.284). In silico analysis suggested that the molecule presents good oral bioavailability and good absorption; penetrating biological membranes. The toxicity tests revealed the potential effectiveness of the molecule in cellular protection against free radicals, in addition to possible antimutagenic, anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and apoptosis agonist activity. Hemolytic and genotoxic assessment detected low hemolysis rates in human red blood cells and no cellular toxicity against oral mucosa cells. The data suggest that vitexin is a safe molecule for possible therapeutic application and its toxicity profile indicates viability for future studies.

In silico, in vitro, and ex vivo studies of the toxicological and pharmacological properties of the flavonoid 5,7-dihydroxy-3,8,4'-trimethoxy.

Phytochemical studies of the species Pavonia glazioviana were performed. Quercetin, kaempferol, acacetin, and trimethoxylated flavonoid compounds (which present biological activity) were isolated. We aimed to evaluate the in silico, in vitro, and ex vivo toxicity of flavonoid 5,7-dihydroxy-3,8,4'-trimethoxy (Pg-1) obtained from P. glazioviana through chemical structure analyses, toxicity assessment, and predictive bioactive properties, using human samples in in vitro tests. In silico analysis suggested that Pg-1 presents a good absorption index for penetrating biological membranes (for oral bioavailability), while also suggesting potential antimutagenic, anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic, and apoptosis agonist bioactivities. Assessment of hemolytic and genotoxic effects revealed low hemolysis rates in red blood cells with no cellular toxicity in oral mucosa cells. The reduced cytotoxic activity suggested the safety of the concentrations used (500-1000 µg/mL), and demonstrated the varied interactions of Pg-1 with the analyzed cells. The data obtained in the present study suggested potential therapeutic application, and the non-toxic profile indicated viability for future studies.

Naphthalimide-based multifunctional AIEgens: Selective, fast, and wash-free fluorescence tracking and identification of Gram-positive bacteria

Pathogenic infections, particularly caused by Gram-positive bacteria (G+), pose a serious threat to human health, and therefore the fast and accurate discrimination of G+ bacteria from Gram-negative bacteria (G–) and fungi is highly desirable. Organic molecules with facile synthesis, robust photostability, good biocompatibility, and high selectivity toward pathogens are urgently needed in the clinical diagnosis and therapy. To this end, herein we report the synthesis of two naphthalimide-based bioprobes named tetraphenylethylene-naphthalimide (TPE-NIM) and triphenylamine-naphthalimide (TPA-NIM) with aggregation-induced emission (AIE) characteristic. First, the staining capacity of the designed AIEgens toward six kinds of bacteria and two kinds of fungi was evaluated. Both TPE-NIM and TPA-NIM showed a high degree of binding/imaging selectivity for G+ bacteria over G− bacteria and fungi via a wash-free protocol. Second, the two AIEgens had the ability to visualize the biofilms formed by G+ bacteria (Staphylococcus aureus) and can quickly track the G+ bacteria (Staphylococcus aureus) in red blood cell suspensions. Third, we have revealed that electrostatic attraction and hydrophobic interaction both contribute to the selective binding of the AIEgens toward G+ bacteria. In view of the high binding/imaging specificity toward G+ bacteria, low hemolysis rates, and low toxicity toward the bacterial cells, these AIEgens can be applied for the clinical detection of pathogenic infections caused by G+ bacteria and broaden the theranostic applications of AIE materials.

In vivo and in simulated body fluid degradation behavior and biocompatibility evaluation of anodic oxidation-silane-chitosan-coated Mg-4.0Zn-0.8Sr alloy for bone application

With the development and progress of science and technology, magnesium and magnesium alloys have attracted more and more researchers' attention because of their excellent biocompatibility. However, rapid degradation rate of magnesium alloy in vivo seriously limits its application (Arthanari et al., n.d.; Cui et al., 2013 [1,2]). In order to solve this problem, the surface modification of Mg-4.0Zn-0.8Sr alloy was adopted in this paper. According to the requirements of orthopedic materials, anodizing coating (AO), silane coating (SA) and chitosan coating (CS) coating were prepared on its surface, and magnesium alloy was prepared into intramedullary nail, and the corrosion resistance and biocompatibility of the corresponding samples was evaluated. The experimental results show that the AO-SA-CS coating sample has higher corrosion resistance, in addition, it also shows good biocompatibility, such as lower hemolysis rate and normal platelet adhesion morphology. After implantation into the femur, the femur of rats recovered well and the kidney tissue was normal.

Preparation and Ultrasonic Imaging Investigation of Perfluoropentane-Filled Polylactic Acid Nanobubbles As a Novel Targeted Ultrasound Contrast Agent

In the study reported here, polylactic acid (PLLA) polymer was synthesized using stannous octoate (Sn(Oct)2) and N-(t-butoxycarbonyl) ethanolamine (EABoc) as the catalyst and the initiator, respectively. The selected PLLA polymer with proper molecular weight was used to prepare nanobubbles encapsulating with liquid perfluoropentane. Then, lactoferrin (Lf), which has a good affinity with tumor cells, was conjugated to PLLA nanobubbles. The resulting Lf–PLLA nanobubbles were examined from the perspective of appearance, size, zeta potential, and stability in vitro. The average hydrodynamic diameter of the Lf–PLLA nanobubbles was 315.3 ± 4.2 nm, the polydispersity index (PDI) was 0.153 ± 0.020, and the zeta potential was around −11.3 ± 0.2 mV. Under the transmission electron microscope (TEM), Lf–PLLA nanobubbles were highly dispersed and had a spherical shape with a distinct capsule structure. The Lf–PLLA nanobubbles also showed little cytotoxicity and low hemolysis rate and exhibited good stability in vitro. The enhanced ultrasound imaging ability of Lf–PLLA nanobubbles was detected by an ultrasound imaging system. The results of ultrasound studies in vitro showed that the liquid perfluoropentane underwent phase transition under ultrasonic treatment, which proved the Lf–PLLA nanobubbles could enhance the ability of ultrasonic imaging. The studies of ultrasonic imaging in nude mice bearing subcutaneous tumors showed that the ability of enhanced ultrasonic images was apparent after injection of Lf–PLLA nanobubbles. Acoustic behavior in vitro and in vivo showed that the Lf–PLLA nanobubbles were characterized by strong, stabilized, and the ability of tumor-enhanced ultrasound imaging. Thus, the Lf–PLLA nanobubbles are an effective ultrasound contrast agent for contrast-enhanced imaging.

Bulk Modification of Thermoplastic Polyurethanes for Self-Sterilization of Trachea Intubation.

Implantable medical devices are widely used, but biomaterial-associated infections (BAIs) impose a huge economic burden and increase the mortality of patients. Therefore, BAIs are a serious concern that must be urgently resolved. Materials with antibacterial properties have become hotspots of current research and development. In the present work, quaternized chitosan (QCS) is used as an antibacterial agent and blended with thermoplastic polyurethane (TPU) to create an antibacterial material for tracheal intubation tubes. The modified TPU material (QCS-TPU) exhibited good mechanical properties and excellent long-term antibacterial performance. Under in vitro hydrodynamic conditions, QCS-TPU retained its strong antibacterial properties. QCS-TPU also possessed a low hemolysis rate and cytotoxicity. The current work is expected to provide a facile and feasible strategy for the preparation of antibacterial catheters and aid in the discovery of promising clinical applications to prevent BAIs.