Theoretical and Experimental Optimization of the Graft Density of Functionalized Anti-Biofouling Surfaces by Cationic Brushes

Diseases and complications related to catheter materials are severe problems in biomedical material applications, increasing the infection risk and medical expenses. Therefore, there is an enormous demand for catheter materials with antibacterial and antifouling properties. Considering this, in this work, we developed an approach of constructing antibacterial surfaces on polyurethane (PU) via surface-initiated atom transfer radical polymerization (SI-ATRP). A variety of cationic polymers were grafted on PU. The biocompatibility and antifouling properties of all resulting materials were evaluated and compared. We also used a theoretical algorithm to investigate the anticoagulant mechanism of our PU-based grafts. The hemocompatibility and anti-biofouling performance improved at a 86–112 μg/cm2 grafting density. The theoretical simulation demonstrated that the in vivo anti-fouling performance and optimal biocompatibility of our PU-based materials could be achieved at a 20% grafting degree. We also discuss the mechanism responsible for the hemocompatibility of the cationic brushes fabricated in this work. The results reported in this paper provide insights and novel ideas on material design for applications related to medical catheters.

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Berberine-Coated Biomimetic Composite Microspheres for Simultaneously Hemostatic and Antibacterial Performance

Polymers ◽

10.3390/polym13030360 ◽

2021 ◽

Vol 13 (3) ◽

pp. 360

Author(s):

Xiaojian Zhang ◽

Kaili Dai ◽

Chenyu Liu ◽

Haofeng Hu ◽

Fulin Luo ◽

...

Keyword(s):

In Vitro Test ◽

Water Emulsion ◽

Biomedical Material ◽

Composite Microspheres ◽

Antibacterial Performance ◽

New Strategy ◽

Oil In Water Emulsion ◽

Hemostatic Powder

Biomimetic microspheres containing alginate/carboxymethylcellulose/gelatin and coated with 0%, 1%, 3%, and 6% berberine (BACG, BACG-1B, BACG-3B, BACG-6B) were prepared by the oil-in-water emulsion method combined with spray drying. Through a series of physicochemical parameters and determination of hemostatic properties in vitro and in vivo, the results indicated that BACG and BACG-Bs were effective in inducing platelet adhesion/aggregation and promoting the hemostatic potential due to their biomimetic structure and rough surface. In addition, BACG-6B with high berberine proportion presented better hemostatic performance compared with the commercial hemostatic agent compound microporous polysaccharide hemostatic powder (CMPHP). BACG-6B also showed strong antibacterial activity in the in vitro test. The hemolysis test and cytotoxicity evaluation further revealed that the novel composite biomaterials have good hemocompatibility and biocompatibility. Thus, BACG-6B provides a new strategy for developing a due-functional (hemostat/antibacterial) biomedical material, which may have broad and promising applications in the future.

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Fabrication, Crystalline Behavior, Mechanical Property and In-Vivo Degradation of Poly(l–lactide) (PLLA)–Magnesium Oxide Whiskers (MgO) Nano Composites Prepared by In-Situ Polymerization

Polymers ◽

10.3390/polym11071123 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1123 ◽

Cited By ~ 4

Author(s):

Hui Liang ◽

Yun Zhao ◽

Jinjun Yang ◽

Xiao Li ◽

Xiaoxian Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Magnesium Oxide ◽

Bone Repair ◽

In Situ Polymerization ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Biomedical Material ◽

In Vivo Degradation

The present work focuses on the preparation of poly(l–lactide)–magnesium oxide whiskers (PLLA–MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA–MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA–MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA–MgO composite to serve as a biomedical material for bone-related repair.

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Cationic Nanostructures for Vaccines Design

Biomimetics ◽

10.3390/biomimetics5030032 ◽

2020 ◽

Vol 5 (3) ◽

pp. 32 ◽

Cited By ~ 2

Author(s):

Ana Maria Carmona-Ribeiro ◽

Yunys Pérez-Betancourt

Keyword(s):

Colloidal Stability ◽

Cationic Lipid ◽

Humoral Response ◽

Cationic Lipids ◽

Cationic Polymers ◽

Polymer Nanostructures ◽

Oppositely Charged ◽

Nanometric Size ◽

Antigen Carrier

Subunit vaccines rely on adjuvants carrying one or a few molecular antigens from the pathogen in order to guarantee an improved immune response. However, to be effective, the vaccine formulation usually consists of several components: an antigen carrier, the antigen, a stimulator of cellular immunity such as a Toll-like Receptors (TLRs) ligand, and a stimulator of humoral response such as an inflammasome activator. Most antigens are negatively charged and combine well with oppositely charged adjuvants. This explains the paramount importance of studying a variety of cationic supramolecular assemblies aiming at the optimal activity in vivo associated with adjuvant simplicity, positive charge, nanometric size, and colloidal stability. In this review, we discuss the use of several antigen/adjuvant cationic combinations. The discussion involves antigen assembled to (1) cationic lipids, (2) cationic polymers, (3) cationic lipid/polymer nanostructures, and (4) cationic polymer/biocompatible polymer nanostructures. Some of these cationic assemblies revealed good yet poorly explored perspectives as general adjuvants for vaccine design.

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In Vitro and In Vivo Immunomodulatory Activities of an Acidic Polysaccharide from Gracilaria lemaneiformis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.468-471.1941 ◽

2012 ◽

Vol 468-471 ◽

pp. 1941-1945 ◽

Cited By ~ 1

Author(s):

Yan Li Fan ◽

Wen Hang Wang ◽

Hong Shuo Chen ◽

Nian Liu ◽

An Jun Liu

Keyword(s):

Neutral Red ◽

Gracilaria Lemaneiformis ◽

Splenocyte Proliferation ◽

Cd4 Cells ◽

Acidic Polysaccharide ◽

Biomedical Material ◽

Macrophage Phagocytosis ◽

Potential Use

The effects of an acidic polysaccharide from Gracilaria lemaneiformis (GLSPs) on the immunomodulation in vitro and in vivo were investigated. It was shown that GLSPs with different concentrations significantly promoted the splenocyte proliferation and macrophage phagocytosis in vitro. In addition, GLSPs also remarkably enhanced the splenocyte proliferation induced by ConA or LPS in mice, notably improved the macrophage phagocytosis towards neutral red, and increased the percentages of CD3+ and CD4+ cells in peripheral blood of mice. The results suggested that GLSPs has significant effect on immunomodulation, and may have biomedical material applications and potential use in stimulating the immune system.

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Structural Optimization of a Wearable Deep Body Thermometer: From Theoretical Simulation to Experimental Verification

Journal of Sensors ◽

10.1155/2016/4828093 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

Ming Huang ◽

Toshiyo Tamura ◽

Zunyi Tang ◽

Wenxi Chen ◽

Shigehiko Kanaya

Keyword(s):

Structural Modification ◽

Measurement Accuracy ◽

Experimental System ◽

The Finite Element Method ◽

Original Design ◽

Standard Type ◽

Deep Body Temperature ◽

Theoretical Simulation ◽

Deep Body

Deep body temperature (DBT) has yet to be measured continuously in everyday life, even though it is useful in physiological monitoring and chronobiology studies. We tried to address this issue by developing a transcutaneous thermometer based on the dual-heat-flux method (DHFM) invoking the principle of heat transfer, for which measurement error was mitigated by elaborate design. First, a structural modification based on the original design of the DHFM was implemented by the finite element method. Based on the results of the simulations, prototypes were then implemented and tested with an experimental system that mimicked the thermometer being applied to skin. The simulation phase proposed the adoption of an aluminum cover to boost measurement accuracy and suggested that thermometers of different height be chosen according to specified requirements. The results of the mock-up experiments support the modification put forward in the simulation phase: the standard type (15 mm in height) achieved the accuracy with error below 0.3°C while the thin type (9 mm in height) attained accuracy with error less than 0.5°C under normal ambient temperature ranging from 20 to 30°C. Even though the design should also be examinedin vivo, it is believed that this study is an important step in developing a practical noninvasive deep body thermometer.

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Construction and Characterizations of Antibacterial Surfaces Based on Self-Assembled Monolayer of Antimicrobial Peptides (Pac-525) Derivatives on Gold

Coatings ◽

10.3390/coatings11091014 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1014

Author(s):

Zijiao Zhang ◽

Ni Kou ◽

Weilong Ye ◽

Shuo Wang ◽

Jiaju Lu ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Self Assembly ◽

The Self ◽

Self Assembled Monolayer ◽

E Coli ◽

Antimicrobial Efficiency ◽

Gold Substrates ◽

Self Assembled ◽

Antibacterial Surfaces

Background: Infection that is related to implanted biomaterials is a serious issue in the clinic. Antimicrobial peptides (AMPs) have been considered as an ideal alternative to traditional antibiotic drugs, for the treatment of infections, while some problems, such as aggregation and protein hydrolysis, are still the dominant concerns that compromise their antimicrobial efficiency in vivo. Methods: In this study, antimicrobial peptides underwent self-assembly on gold substrates, forming good antibacterial surfaces, with stable antibacterial behavior. The antimicrobial ability of AMPs grafted on the surfaces, with or without glycine spaces or a primer layer, was evaluated. Results: Specifically, three Pac-525 derivatives, namely, Ac-CGn-KWRRWVRWI-NH2 (n = 0, 2, or 6) were covalently grafted onto gold substrates via the self-assembling process for inhibiting the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, the alkanethiols HS(CH)10SH were firstly self-assembled into monolayers, as a primer layer (SAM-SH) for the secondary self-assembly of Pac-525 derivatives, to effectively enhance the bactericidal performance of the grafted AMPs. The -(CH)10-S-S-G6Pac derivative was highly effective against S. aureus and E. coli, and reduced the viable amount of E. coli and S. aureus to 0.4% and 33.2%, respectively, after 24 h of contact. In addition, the immobilized AMPs showed good biocompatibility, promoting bone marrow stem cell proliferation. Conclusion: the self-assembled monolayers of the Pac-525 derivatives have great potential as a novel therapeutic method for the treatment of implanted biomaterial infections.

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The Adoption of Three-Dimensional Additive Manufacturing from Biomedical Material Design to 3D Organ Printing

Applied Sciences ◽

10.3390/app9040811 ◽

2019 ◽

Vol 9 (4) ◽

pp. 811 ◽

Cited By ~ 16

Author(s):

Ajay Vikram Singh ◽

Mohammad Hasan Dad Ansari ◽

Shuo Wang ◽

Peter Laux ◽

Andreas Luch ◽

...

Keyword(s):

Organ Transplant ◽

Three Dimensional ◽

Material Design ◽

3D Bioprinting ◽

Biomedical Material ◽

Recent Developments ◽

Physicochemical Basis ◽

Organ Printing ◽

3D Spheroids ◽

The Way

Three-dimensional (3D) bioprinting promises to change future lifestyle and the way we think about aging, the field of medicine, and the way clinicians treat ailing patients. In this brief review, we attempt to give a glimpse into how recent developments in 3D bioprinting are going to impact vast research ranging from complex and functional organ transplant to future toxicology studies and printed organ-like 3D spheroids. The techniques were successfully applied to reconstructed complex 3D functional tissue for implantation, application-based high-throughput (HTP) platforms for absorption, distribution, metabolism, and excretion (ADME) profiling to understand the cellular basis of toxicity. We also provide an overview of merits/demerits of various bioprinting techniques and the physicochemical basis of bioink for tissue engineering. We briefly discuss the importance of universal bioink technology, and of time as the fourth dimension. Some examples of bioprinted tissue are shown, followed by a brief discussion on future biomedical applications.

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Investigation of DNA Spectral Conformational Changes and Polymer Buffering Capacity in Relation to Transfection Efficiency of DNA/Polymer Complexes

Journal of Pharmacy & Pharmaceutical Sciences ◽

10.18433/j3859k ◽

2009 ◽

Vol 12 (3) ◽

pp. 346 ◽

Cited By ~ 14

Author(s):

Jong Yuh Cherng

Keyword(s):

Conformational Changes ◽

Transfection Efficiency ◽

Dna Interaction ◽

Buffering Capacity ◽

Cationic Polymers ◽

Polymer Complexes ◽

Before And After ◽

Stretching Vibration

Purpose. The relation between transfection efficiency of DNA/polymer complexes and DNA conformational alterations is investigated. The buffering capacity of several synthetic polymers is also studied to relate their performance in transfection efficiency. Methods. The cationic polymer/DNA interaction was evaluated by measuring the alteration of DNA secondary structures in solution before and after the addition of polymer with ATR-FTIR technique. The degree of protonation in aqueous cationic polymers is varied upon pH and different structures. A polymer capable of protonation acts like a proton sponge to react with H+ in titration with HCl. This characteristic was evaluated in relation to transfection efficiency because the capacity would help the release of endocytotic DNA from endosome/lysosome on its way to expression. Results. IR results show that the antisymmetric PO2- vibration of DNA (at 1224 cm-1) shifts toward lower frequencies in complexation with PEI or PLLys (these polymers are able to transfect DNA). By contrast, the antisymmetric PO2- vibration of DNA in presence of PDAMA or dextran (these polymers are poor in DNA transfection) shows a shifting to higher frequencies or no alteration was observed. Interestingly, the polymers with best performance in transfection efficiency are in this order: PEI>PDMAEMA>PLLys>PDAMA>dextran which is in the same order as their polymer buffering capacity. These facts indicate polymers possessing better buffering capacity could result in higher transfection efficiency. Also, we have demonstrated in this paper that the antisymmetric PO2- stretching vibration in IR spectra is sensitive while binding of cationic polymers to DNA. These findings are useful for the development of polymer-based gene delivery systems with better performance in vitro and in vivo

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A High-Throughput Device for Patterned Differentiation of Embryoid Bodies

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2013.p0623 ◽

2013 ◽

Vol 25 (4) ◽

pp. 623-630 ◽

Cited By ~ 2

Author(s):

Xiaoming He ◽

◽

Hiroshi Kimura ◽

Teruo Fujii ◽

◽

...

Keyword(s):

Microfluidic Device ◽

Embryoid Body ◽

Embryoid Bodies ◽

Culture Methods ◽

Theoretical Simulation ◽

Chemical Gradients ◽

Conventional Culture ◽

Differentiation And Proliferation

Although ontogenesis in vivo may proceed in a spatiotemporally heterogeneous environment, in vitro differentiation of an embryoid body (EB) has been carried out in uniform conditions using conventional culture methods at low throughput. In the present study, a microfluidic device with multiple culture chambers for simultaneous patterned differentiation of multiple EBs of pluripotent stem cells is newly developed. Theoretical simulation and experiments using a suspension of fluorescent particles or fluorescent solution show that proper chemical gradients can be formed with almost no flow in the chambers. After multiple EBs are introduced into the device, these EBs move along the flow channel and into trapping cups. The EBs are pushed by air bubbles into the culture chambers. These multiple EBs can be cultured within the culture chambers after flowing culture medium removes the air bubble from the device. In our experiment, differentiation and proliferation of these multiple EBs are studied by exposing them to two different media for 6 days: one to induce differentiation and the other to keep the pluripotent and self-renewing state of the cells. It is shown that patterned differentiation of the multiple EBs is successfully conducted simultaneously in the device when these two media are perfused into the device. The results suggest that differentiation and proliferation of multiple EBs can be analyzed by applying chemical gradients in the present microfluidic device. This will be a helpful tool in a wide variety of experiments involving EBs or spheroids.

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