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2.
J Vasc Interv Radiol ; 32(6): 882-889, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33689833

RESUMO

PURPOSE: To compare the performance of a dual-lumen flushable drainage catheter to a conventional catheter for complex fluid collection drainage. METHODS: Two prototype catheters (20- and 28-F) were created by incorporating a customized infusion lumen within the wall of a large-bore conventional drainage catheter, which facilitated simultaneous irrigation of the drainage lumen and the targeted collection via inward- and outward-facing infusion side holes. These were tested against unaltered 20- and 28-F conventional catheters to determine if the injection of a dedicated flush lumen improved rapidity and completeness of gravity drainage. In vitro models were created to simulate serous fluid, purulent/exudative fluid, particulate debris, and acute hematoma. RESULTS: In the purulent model, mean drainage rate was 19.9 ± 8.0 and 9.5±1.4 mL/min for the 20-F prototype and control (P < .001) and 63.9 ± 4.3 and 35.4 ± 3.4 mL/min for the 28-F prototype and control (P = .006), respectively, with complete drainage achieved in all trials. In the particulate model, mean drainage rate was 24.5 ± 9.7 and 12.0 ± 12.5 mL/min for the 28-F prototype and control (P = .003), respectively, with 69.0% versus 41.1% total drainage achieved over 24 minutes (P = .029). In the hematoma model, mean drainage rate was 22.7 ± 4.6 and 4.8 ± 4.3 mL/min for the 28-F prototype and control (P = .022), respectively, with 80.3% versus 20.1% drainage achieved over 15 minutes (P = .003). Particulate and hematoma 20-F prototypes and conventional trials failed due to immediate occlusion. CONCLUSIONS: The proposed dual-lumen drainage catheter with irrigation of a dedicated flush lumen improved evacuation of complex fluid collections in vitro.


Assuntos
Cateterismo/instrumentação , Catéteres , Drenagem/instrumentação , Irrigação Terapêutica/instrumentação , Desenho de Equipamento , Teste de Materiais , Fatores de Tempo
3.
Small Methods ; 4(1)2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33043130

RESUMO

Microphysiological systems, also known as organ-on-a-chip platforms, show promise for the development of new testing methods that can be more accurate than both conventional two-dimensional cultures and costly animal studies. The development of more intricate microphysiological systems can help to better mimic the human physiology and highlight the systemic effects of different drugs and materials. Nanomaterials are among a technologically important class of materials used for diagnostic, therapeutic, and monitoring purposes; all of which and can be tested using new organ-on-a-chip systems. In addition, the toxicity of nanomaterials which have entered the body from ambient air or diet can have deleterious effects on various body systems. This in turn can be studied in newly developed microphysiological systems. While organ-on-a-chip models can be useful, they cannot pick up secondary and systemic toxicity. Thus, the utilization of multi-organ-on-a-chip systems for advancing nanotechnology will largely be reflected in the future of drug development, toxicology studies and precision medicine. Various aspects of related studies, current challenges, and future perspectives are discussed in this paper.

4.
Small ; 16(29): e2000171, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32529791

RESUMO

Cell separation is a key step in many biomedical research areas including biotechnology, cancer research, regenerative medicine, and drug discovery. While conventional cell sorting approaches have led to high-efficiency sorting by exploiting the cell's specific properties, microfluidics has shown great promise in cell separation by exploiting different physical principles and using different properties of the cells. In particular, label-free cell separation techniques are highly recommended to minimize cell damage and avoid costly and labor-intensive steps of labeling molecular signatures of cells. In general, microfluidic-based cell sorting approaches can separate cells using "intrinsic" (e.g., fluid dynamic forces) versus "extrinsic" external forces (e.g., magnetic, electric field, etc.) and by using different properties of cells including size, density, deformability, shape, as well as electrical, magnetic, and compressibility/acoustic properties to select target cells from a heterogeneous cell population. In this work, principles and applications of the most commonly used label-free microfluidic-based cell separation methods are described. In particular, applications of microfluidic methods for the separation of circulating tumor cells, blood cells, immune cells, stem cells, and other biological cells are summarized. Computational approaches complementing such microfluidic methods are also explained. Finally, challenges and perspectives to further develop microfluidic-based cell separation methods are discussed.


Assuntos
Técnicas Analíticas Microfluídicas , Células Neoplásicas Circulantes , Contagem de Células , Separação Celular , Humanos , Microfluídica
5.
Acta Biomater ; 112: 190-201, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32434076

RESUMO

Microfluidic artificial lungs (µALs) have the potential to improve the treatment and quality of life for patients with acute or chronic lung injury. In order to realize the full potential of this technology (including as a destination therapy), the biocompatibility of these devices needs to be improved to produce long-lasting devices that are safe for patient use with minimal or no systemic anticoagulation. Many studies exist which probe coagulation and thrombosis on polydimethyl siloxane (PDMS) surfaces, and many strategies have been explored to improve surface biocompatibility. As the field of µALs is young, there are few studies which investigate biocompatibility of functioning µALs; and even fewer which were performed in vivo. Here, we use both in vitro and in vivo models to investigate two strategies to improve µAL biocompatibility: 1) a hydrophilic surface coating (polyethylene glycol, PEG) to prevent surface fouling, and 2) the addition of nitric oxide (NO) to the sweep gas to inhibit platelet activation locally within the µAL. In this study, we challenge µALs with clottable blood or platelet-rich plasma (PRP) and monitor the resistance to blood flow over time. Device lifetime (the amount of time the µAL remains patent and unobstructed by clot) is used as the primary indicator of biocompatibility. This study is the first study to: 1) investigate the effect of NO release on biocompatibility in a microfluidic network; 2) combine a hydrophilic PEG coating with NO release to improve blood compatibility; and 3) perform extended in vivo biocompatibility testing of a µAL. We found that µALs challenged in vitro with PRP remained patent significantly longer when the sweep gas contained NO than without NO. In the in vivo rabbit model, neither approach alone (PEG coating nor NO sweep gas) significantly improved biocompatibility compared to controls (though with larger sample size significance may become apparent); while the combination of a PEG coating with NO sweep gas resulted in significant improvement of device lifetime. STATEMENT OF SIGNIFICANCE: The development of microfluidic artificial lungs (µALs) can potentially have a massive impact on the treatment of patients with acute and chronic lung impairments. Before these devices can be deployed clinically, the biocompatibility of µALs must be improved and more comprehensively understood. This work explores two strategies for improving biocompatibility, a hydrophilic surface coating (polyethylene glycol) for general surface passivation and the addition of nitric oxide (NO) to the sweep gas to quell platelet and leukocyte activation. These two strategies are investigated separately and as a combined device treatment. Devices are challenged with clottable blood using in vitro testing and in vivo testing in rabbits. This is the first study to our knowledge that allows statistical comparisons of biocompatible µALs in animals, a key step towards eventual clinical use.


Assuntos
Microfluídica , Qualidade de Vida , Animais , Plaquetas , Humanos , Interações Hidrofóbicas e Hidrofílicas , Pulmão , Coelhos
6.
Small ; 16(25): e2001837, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32419312

RESUMO

Stem cells secrete trophic factors that induce angiogenesis. These soluble factors are promising candidates for stem cell-based therapies, especially for cardiovascular diseases. Mechanical stimuli and biophysical factors presented in the stem cell microenvironment play important roles in guiding their behaviors. However, the complex interplay and precise role of these cues in directing pro-angiogenic signaling remain unclear. Here, a platform is designed using gelatin methacryloyl hydrogels with tunable rigidity and a dynamic mechanical compression bioreactor to evaluate the influence of matrix rigidity and mechanical stimuli on the secretion of pro-angiogenic factors from human mesenchymal stem cells (hMSCs). Cells cultured in matrices mimicking mechanical elasticity of bone tissues in vivo show elevated secretion of vascular endothelial growth factor (VEGF), one of representative signaling proteins promoting angiogenesis, as well as increased vascularization of human umbilical vein endothelial cells (HUVECs) with a supplement of conditioned media from hMSCs cultured across different conditions. When hMSCs are cultured in matrices stimulated with a range of cyclic compressions, increased VEGF secretion is observed with increasing mechanical strains, which is also in line with the enhanced tubulogenesis of HUVECs. Moreover, it is demonstrated that matrix stiffness and cyclic compression modulate secretion of pro-angiogenic molecules from hMSCs through yes-associated protein activity.


Assuntos
Células-Tronco Mesenquimais , Células Cultivadas , Sinais (Psicologia) , Meios de Cultivo Condicionados , Células Endoteliais da Veia Umbilical Humana , Humanos , Neovascularização Fisiológica , Fator A de Crescimento do Endotélio Vascular
7.
ACS Appl Mater Interfaces ; 12(18): 20158-20171, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32271542

RESUMO

The management of thrombosis and bacterial infection is critical to ensure the functionality of medical devices. While administration of anticoagulants is the current antithrombotic clinical practice, a variety of complications, such as uncontrolled hemorrhages or heparin-induced thrombocytopenia, can occur. Additionally, infection rates remain a costly and deadly complication associated with use of these medical devices. It has been hypothesized that if a synthetic surface could mimic the biochemical mechanisms of the endothelium of blood vessels, thrombosis could be reduced, anticoagulant use could be avoided, and infection could be prevented. Herein, the interfacial biochemical effects of the endothelium were mimicked by altering the surface of medical grade silicone rubber (SR). Surface modification was accomplished via heparin surface immobilization (Hep) and the inclusion of a nitric oxide (NO) donor into the SR polymeric matrix to achieve synergistic effects (Hep-NO-SR). An in vitro bacteria adhesion study revealed that Hep-NO-SR exhibited a 99.46 ± 0.17% reduction in viable bacteria adhesion compared to SR. An in vitro platelet study revealed Hep-NO-SR reduced platelet adhesion by 84.12 ± 6.19% compared to SR, while not generating a cytotoxic response against fibroblast cells. In a 4 h extracorporeal circuit model without systemic anticoagulation, all Hep-NO-SR samples were able to maintain baseline platelet count and device patency; whereas 66% of SR samples clotted within the first 2 h of study. Results indicate that Hep-NO-SR creates a more hemocompatible and antibacterial surface by mimicking two key biochemical functions of the native endothelium.


Assuntos
Materiais Biomiméticos/química , Fármacos Hematológicos/uso terapêutico , Heparina/uso terapêutico , Doadores de Óxido Nítrico/uso terapêutico , S-Nitroso-N-Acetilpenicilamina/uso terapêutico , Animais , Aderência Bacteriana/efeitos dos fármacos , Materiais Biomiméticos/toxicidade , Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/metabolismo , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/toxicidade , Endotélio/química , Fármacos Hematológicos/farmacologia , Fármacos Hematológicos/toxicidade , Heparina/farmacologia , Heparina/toxicidade , Proteínas Imobilizadas/farmacologia , Proteínas Imobilizadas/uso terapêutico , Proteínas Imobilizadas/toxicidade , Camundongos , Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/farmacologia , Doadores de Óxido Nítrico/toxicidade , Adesividade Plaquetária/efeitos dos fármacos , Coelhos , S-Nitroso-N-Acetilpenicilamina/farmacologia , S-Nitroso-N-Acetilpenicilamina/toxicidade , Elastômeros de Silicone/química , Elastômeros de Silicone/toxicidade , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície
8.
Biotechnol Bioeng ; 117(7): 2237-2246, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32215917

RESUMO

The chances of ventilator-associated pneumonia (VAP) increases 6-20 folds when an endotracheal tube (ETT) is placed in a patient. VAP is one of the most common hospital-acquired infections and comprises 86% of the nosocomial pneumonia cases. This study introduces the idea of nitric oxide-releasing ETTs (NORel-ETTs) fabricated by the incorporation of the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP) into commercially available ETTs via solvent swelling. The impregnation of SNAP provides NO release over a 7-day period without altering the mechanical properties of the ETT. The NORel-ETTs successfully reduced the bacterial infection from a commonly found pathogen in VAP, Pseudomonas aeruginosa, by 92.72 ± 0.97% when compared with the control ETTs. Overall, this study presents the incorporation of the active release of a bactericidal agent in ETTs as an efficient strategy to prevent the risk of VAP.


Assuntos
Antibacterianos/administração & dosagem , Intubação Intratraqueal/instrumentação , Doadores de Óxido Nítrico/administração & dosagem , Pneumonia Associada à Ventilação Mecânica/prevenção & controle , S-Nitroso-N-Acetilpenicilamina/administração & dosagem , Antibacterianos/farmacologia , Liberação Controlada de Fármacos , Humanos , Intubação Intratraqueal/métodos , Doadores de Óxido Nítrico/farmacologia , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , S-Nitroso-N-Acetilpenicilamina/farmacologia
9.
ACS Appl Mater Interfaces ; 12(8): 9070-9079, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32009376

RESUMO

The development of nonfouling and antimicrobial materials has shown great promise for reducing thrombosis and infection associated with medical devices with aims of improving device safety and decreasing the frequency of antibiotic administration. Here, the design of an antimicrobial, anti-inflammatory, and antithrombotic vascular catheter is assessed in vivo over 7 d in a rabbit model. Antimicrobial and antithrombotic activity is achieved through the integration of a nitric oxide donor, while the nonfouling surface is achieved using a covalently bound phosphorylcholine-based polyzwitterionic copolymer topcoat. The effect of sterilization on the nonfouling nature and nitric oxide release is presented. The catheters reduced viability of Staphylococcus aureus in long-term studies (7 d in a CDC bioreactor) and inflammation in the 7 d rabbit model. Overall, this approach provides a robust method for decreasing thrombosis, inflammation, and infections associated with vascular catheters.


Assuntos
Antibacterianos , Infecções Relacionadas a Cateter/prevenção & controle , Catéteres , Materiais Revestidos Biocompatíveis , Óxido Nítrico , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/crescimento & desenvolvimento , Trombose/prevenção & controle , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Óxido Nítrico/química , Óxido Nítrico/farmacologia , Coelhos
10.
ACS Appl Bio Mater ; 3(11): 7677-7686, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-35019507

RESUMO

Blended and coaxial fibers comprising polycaprolactone and gelatin, containing the endogenous nitric oxide (NO) donor S-nitrosoglutathione (GSNO), were electrospun. Both types of fibers had their NO release profiles tested under physiological conditions to examine their potential applications as biomedical scaffolds. The coaxial fibers exhibited a prolonged and consistent release of NO over the course of 4 d from the core-encapsulated GSNO, while the blended fibers had a large initial release and leaching of GSNO that was exhausted over a shorter period of time. Bacterial testing of both fiber scaffolds was conducted over a 24 h period against Staphylococcus aureus (S. aureus) and demonstrated a 3-log reduction in bacterial viability. In addition, no cytotoxic response was reported when the material was tested on mouse fibroblast cells in vitro. These fibrous matrices were also shown to support cell growth, attachment, and overall activity of fibroblasts when exposed to NO, especially when GSNO was encapsulated within coaxial fibers. From an application point of view, these NO-releasing fibers offer great potential in tissue engineering and biomedical applications because of the crucial role of NO in regulating a variety of biological processes in humans such as angiogenesis, tissue remodeling, and eliminating foreign pathogens.

11.
Adv Drug Deliv Rev ; 165-166: 41-59, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31837356

RESUMO

Microneedles (MNs) have been used to deliver drugs for over two decades. These platforms have been proven to increase transdermal drug delivery efficiency dramatically by penetrating restrictive tissue barriers in a minimally invasive manner. While much of the early development of MNs focused on transdermal drug delivery, this technology can be applied to a variety of other non-transdermal biomedical applications. Several variations, such as multi-layer or hollow MNs, have been developed to cater to the needs of specific applications. The heterogeneity in the design of MNs has demanded similar variety in their fabrication methods; the most common methods include micromolding and drawing lithography. Numerous materials have been explored for MN fabrication which range from biocompatible ceramics and metals to natural and synthetic biodegradable polymers. Recent advances in MN engineering have diversified MNs to include unique shapes, materials, and mechanical properties that can be tailored for organ-specific applications. In this review, we discuss the design and creation of modern MNs that aim to surpass the biological barriers of non-transdermal drug delivery in ocular, vascular, oral, and mucosal tissue.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Microinjeções/instrumentação , Microinjeções/métodos , Administração Tópica , Transporte Biológico , Desenho de Equipamento , Humanos , Microtecnologia/métodos , Polímeros , Próteses e Implantes
12.
ACS Appl Mater Interfaces ; 11(4): 4523-4530, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30607929

RESUMO

Two major challenges faced by medical devices are thrombus formation and infection. In this work, surface-tethered nitric oxide (NO)-releasing molecules are presented as a solution to combat infection and thrombosis. These materials possess a robust NO release capacity lasting ca. 1 month while simultaneously improving the nonfouling nature of the material by preventing platelet, protein, and bacteria adhesion. NO's potent bactericidal function has been implemented by a facile surface covalent attachment method to fabricate a triple-action coating-surface-immobilized S-nitroso- N-acetylpenicillamine (SIM-S). Comparison of NO loading amongst the various branching configurations is shown through the NO release kinetics over time and the cumulative NO release. Biological characterization is performed using in vitro fibrinogen and Staphylococcus aureus assays. The material with the highest NO release, SIM-S2, is also able to reduce protein adhesion by 65.8 ± 8.9% when compared to unmodified silicone. SIM-S2 demonstrates a 99.99% (i.e., ∼4 log) reduction for S. aureus over 24 h. The various functionalized surfaces significantly reduce platelet adhesion in vitro, for both NO-releasing and non-NO-releasing surfaces (up to 89.1 ± 0.9%), demonstrating the nonfouling nature of the surface-immobilized functionalities. The ability of the SIM-S surfaces to retain antifouling properties despite gradual depletion of the bactericidal source, NO, demonstrates its potential use in long-term medical implants.


Assuntos
Antibacterianos/química , Anti-Infecciosos/química , Inibidores da Agregação Plaquetária/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Humanos , Óxido Nítrico/química , Inibidores da Agregação Plaquetária/farmacologia , S-Nitroso-N-Acetilpenicilamina/química , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície
14.
ACS Appl Bio Mater ; 2(6): 2539-2548, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-33718805

RESUMO

Devices used for extracorporeal circulation are met with two major medical concerns: thrombosis and infection. A device that allows for anticoagulant-free circulation while reducing risk of infection has yet to be developed. We report the use of a copper nanoparticle (Cu NP) catalyst for the release of nitric oxide (NO) from the endogenous donor S-nitrosoglutathione (GSNO) in a coating applied to commercial Tygon S3™ E-3603 poly(vinyl chloride) tubing in order to reduce adhered bacterial viability and the occurrence thrombosis for the first time in an animal model. Cu GSNO coated material demonstrated a nitric oxide (NO) release flux ranging from an initial flux of 6.3 ± 0.9 ×10-10 mol cm-2 min-1 to 7.1 ± 0.4 ×10-10 mol cm-2 min-1 after 4 h of release, while GSNO loops without Cu NPs only ranged from an initial flux of 1.1 ± 0.2 ×10-10 mol cm-2 min-1 to 2.3 ± 0.2 ×10-10 mol cm-2 min-1 after 4 h of release, indicating that the addition of Cu NPs can increase NO flux up to five times in the same 4 h period. Additionally, a 3-log reduction in S. aureus and 1-log reduction in P. aeruginosa was observed in viable bacterial adhesion over a 24 h period compared to control loops. A Cell Counting Kit-8 (CCK-8) assay was used to validate no overall cytotoxicity towards 3T3 mouse fibroblasts. Finally, extracorporeal circuits were coated and exposed to 4 h of blood flow under an in vivo rabbit model. The Cu GSNO combination was successful in maintaining 89.3% of baseline platelet counts, while the control loops were able to maintain 67.6% of the baseline. These results suggest that the combination of Cu NPs with GSNO increases hemocompatibility and antimicrobial properties of ECC loops without any cytotoxic effects towards mammalian cells.

15.
ACS Biomater Sci Eng ; 5(4): 2021-2029, 2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33405516

RESUMO

Urinary catheterization is one of the most common medical procedures that makes a patient susceptible to infection due to biofilm formation on the urinary catheter. Catheter associated urinary tract infections (CAUTIs) are responsible for over 1 million cases in the United States alone and cost the healthcare industry more than $350 million every year. This work presents a liquid-infused nitric-oxide-releasing (LINORel) urinary catheter fabricated by incorporating the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP) and silicone oil into commercial silicone Foley catheters through a two-stage swelling process. This synergistic combination improves NO-releasing materials by providing minimal SNAP leaching and a more controlled release of NO while incorporating the nonfouling characteristics of liquid-infused materials. The LINORel urinary catheter was successful in sustaining a controlled NO release over a 60 day period under physiological conditions with minimal SNAP leaching during the initial 24 h period, 0.49 ± 0.0061%. The LINORel-UC proved successful in reducing bacterial adhesion and biofilm formation for Gram positive Staphylococcus aureus (98.49 ± 2.06%) over a 7 day period in a drip flow bioreactor environment. Overall, this study presents a desirable combination that incorporates the antifouling advantages of liquid-infused materials with the active release of a bactericidal agent, an uncharted territory in aiding to prevent the risk of CAUTIs.

16.
ACS Biomater Sci Eng ; 5(8): 4002-4012, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-33443422

RESUMO

Biological processes such as infection, angiogenesis, and fibroblast proliferation and migration need to be regulated for effective healing of a wound. Failing to do so can delay the overall wound healing and add to the suffering and healthcare cost. Endogenous nitric oxide (NO) is a well-known gasotransmitter in the natural healing process in humans and other mammals. To utilize its inherent ability in the current study, an exogenous NO donor (S-nitroso-glutathione, GSNO) was integrated into a hybrid formulation consisting of a natural polymer (alginate) and a synthetic polymer (poly(vinyl alcohol) (PVA)). The alginate-PVA-GSNO dressings showed a sustained NO release for 72 h that resulted in 99.89 ± 0.40% and 98.93 ± 0.69% eradication of Staphylococcus aureus and Pseudomonas aeruginosa, respectively, which are among the most common causal agents of wound infections. The designed dressings resulted in a 3-fold increase in the proliferation of human endothelial cells when compared with control without GSNO showing its angiogenic potential. In addition, mouse fibroblast cells exposed to leachates from alginate-PVA-GSNO dressings showed significantly higher proliferation when compared to control alginate-PVA showing the NO release from exogenous GSNO in fibroblast proliferation. Fibroblast migration was shown to be much faster with GSNO-based dressings when compared to corresponding control dressings resulting in complete closure of an in vitro wound model within 48 h. The porous dressings also possessed important physical properties such as swelling, water vapor transmission, and moisture content that are desirable for effective wound healing. Overall, this study supports the possibility of using therapeutic alginate-PVA-GSNO dressing to provide a supportive environment for accelerated wound healing.

17.
J Biomed Mater Res B Appl Biomater ; 107(4): 1068-1078, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30230685

RESUMO

Open bone fractures are not only difficult to heal but also are at a high risk of infections. Annual cases of fractures which result from osteoporosis amount to approximately 9 million. Endogenously released nitric oxide (NO) has been shown to play a role in osteogenic differentiation in addition to eradicating infection against a wide variety of pathogens. In the current work, antimicrobial NO releasing 3D bone scaffolds were fabricated using S-nitroso-N-acetyl-penicillamine (SNAP) as the NO donor. During fabrication, nano-hydroxyapatite (nHA) was added to each of the scaffolds in the concentration range of 10-50 wt % in nHA-starch-alginate and nHA-starch-chitosan scaffolds. The mechanical strength of the scaffolds increased proportionally to the concentration of nHA and 50 wt % nHA-starch-alginate possessed the highest load bearing capacity of 203.95 ± 0.3 N. The NO flux of the 50 wt % nHA-starch-alginate scaffolds was found to be 0.50 ± 0.06 × 10-10 mol/min/mg initially which reduced to 0.23 ± 0.02 × 10-10 over a 24 h period under physiological conditions. As a result, a 99.76% ± 0.33% reduction in a gram-positive bacterium, Staphylococcus aureus and a 99.80% ± 0.62% reduction in the adhered viable colonies of gram-negative bacterium, Pseudomonas aeruginosa were observed, which is a significant stride in the field of antibacterial natural polymers. The surface morphology and pore size were observed to be appropriate for the potential bone cell growth. The material showed no toxic response toward mouse fibroblast cells. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1068-1078, 2019.


Assuntos
Antibacterianos , Osso e Ossos , Pseudomonas aeruginosa/crescimento & desenvolvimento , S-Nitroso-N-Acetilpenicilamina , Staphylococcus aureus/crescimento & desenvolvimento , Engenharia Tecidual , Alicerces Teciduais/química , Células 3T3 , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/química , Quitosana/farmacologia , Camundongos , S-Nitroso-N-Acetilpenicilamina/química , S-Nitroso-N-Acetilpenicilamina/farmacologia , Amido/química , Amido/farmacologia
18.
ACS Appl Mater Interfaces ; 10(32): 27316-27325, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30028941

RESUMO

Ever since the role of endogenous nitric oxide (NO) in controlling a wide variety of biological functions was discovered approximately three decades back, multiple NO-releasing polymeric materials have been developed. However, most of these materials are typically short lived due to the inefficient incorporation of the NO donor molecules within the polymer matrix. In the present study, S-nitroso- N-acetyl penicillamine (SNAP) is covalently attached to poly(dimethylsiloxane) (PDMS) to create a highly stable nitric oxide (NO) releasing material for biomedical applications. By tethering SNAP to the cross-linker of PDMS, the NO donor is unable to leach into the surrounding environment. This is the first time that a sustainable NO release and bacterial inhibition for over 125 days has been achieved by any NO-releasing polymer with supporting evidence of potential long-term hemocompatibility and biocompatibility. The material proves to have very high antibacterial efficacy against Staphylococcus aureus by demonstrating a 99.99% reduction in the first 3 days in a continuous flow CDC bioreactor, whereas a similar inhibitory potential of 99.50% was maintained by the end of 1 month. Hemocompatibility of SNAP-PDMS was tested using a rabbit extracorporeal circuit (ECC) model over a 4 h period. Thrombus formation was greatly reduced within the SNAP-PDMS-coated ECCs compared to the control circuits, observing a 78% reduction in overall thrombus mass accumulation. These results demonstrate the potential of utilizing this material for blood and tissue contacting biomedical devices in long-term clinical applications where infection and unwanted clotting are major issues.


Assuntos
Óxido Nítrico/química , Animais , Doadores de Óxido Nítrico , Penicilamina/análogos & derivados , Coelhos , S-Nitroso-N-Acetilpenicilamina , Silicones
19.
J Biomed Mater Res A ; 106(6): 1535-1542, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29377589

RESUMO

Designing innovative materials for biomedical applications is desired to prevent surface fouling and risk of associated infections arising in the surgical care patient. In the present study, albumin plastic was fabricated and nitric oxide (NO) donor, S-nitroso-N-acetylpenicillamine (SNAP), was incorporated through a solvent swelling process. The albumin-SNAP plastic was evaluated in terms of mechanical and thermal properties, and bacterial adhesion to the plastic surface. Thermal and viscoelastic analyses showed no significant difference between albumin-SNAP plastics and pure, water-plasticized albumin samples. Bacteria adhesion tests revealed that albumin-SNAP plastic can significantly reduce the surface-bound viable gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa bacterial cells by 98.7 and 98.5%, respectively, when compared with the traditional polyvinyl chloride medical grade tubing material. The results from this study demonstrate NO-releasing albumin plastic's potential as a material for biomedical device applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1535-1542, 2018.


Assuntos
Albuminas/química , Aderência Bacteriana/efeitos dos fármacos , Infecções Bacterianas/prevenção & controle , Materiais Biocompatíveis/química , Doadores de Óxido Nítrico/administração & dosagem , Plásticos/química , S-Nitroso-N-Acetilpenicilamina/administração & dosagem , Infecções Bacterianas/etiologia , Equipamentos e Provisões/efeitos adversos , Equipamentos e Provisões/microbiologia , Humanos , Doadores de Óxido Nítrico/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , S-Nitroso-N-Acetilpenicilamina/farmacologia , Staphylococcus aureus/efeitos dos fármacos
20.
J Biomed Mater Res B Appl Biomater ; 106(8): 2849-2857, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29266734

RESUMO

The interaction of blood proteins with an implant surface is not only a fundamental phenomenon but is also key to several important medical complications. Plasma proteins binding on the surface of intravascular catheters can promote bacterial adhesion leading to the risk of local and systemic complications such as catheter-related blood infections (CRBIs). The incidences of CRBIs in the United States amount to more than 250,000 cases/year with an attributable mortality of up to 35% and an annual healthcare expenditure of $2.3 billion approximately. This demands the development of truly nonthrombogenic and antimicrobial catheters. In the present study, catheters were fabricated by incorporating a nitric oxide (NO) donor molecule, S-nitroso-N-acetyl-penicillamine (SNAP) in a hydrophobic medical grade polymer, Elasteon-E2As. NO offers antithrombotic and antibacterial attributes without promoting drug resistance and cytotoxicity. E2As-SNAP catheters were first coated with fibrinogen, a blood plasma protein plays a key role in clot formation and eventual bacterial adhesion to the implant surface. The suitability of the catheters for biomedical applications was tested in vitro for contact angle, NO release kinetics, inhibition of bacteria, and absence of cytotoxicity toward mammalian cells. The highly hydrophobic catheters released NO in the physiological range that inhibited >99% bacterial viability on fibrinogen-coated catheters in a 24 h study. No toxic response of E2As-SNAP catheters leachate was observed using a standard cytotoxicity assay with mouse fibroblast cells. Overall, the results showed that the E2As-SNAP catheters can inhibit viable bacteria even in the presence of blood proteins without causing a cytotoxic response. The fundamentals of this study are applicable to other blood-contacting medical devices as well. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2849-2857, 2018.


Assuntos
Infecções Relacionadas a Cateter/prevenção & controle , Catéteres , Escherichia coli/crescimento & desenvolvimento , Óxido Nítrico , S-Nitroso-N-Acetilpenicilamina , Staphylococcus aureus/crescimento & desenvolvimento , Animais , Proteínas Sanguíneas/química , Linhagem Celular , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Teste de Materiais , Camundongos , Óxido Nítrico/química , Óxido Nítrico/farmacocinética , Óxido Nítrico/farmacologia , S-Nitroso-N-Acetilpenicilamina/química , S-Nitroso-N-Acetilpenicilamina/farmacocinética , S-Nitroso-N-Acetilpenicilamina/farmacologia
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