Browsing by Author "Maitz, Manfred F."
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- ItemAdhesive and Self-Healing Polyurethanes with Tunable Multifunctionality([Beijing] : China Association for Science and Technology, 2022) Zhou, Lei; Zhang, Lu; Li, Peichuang; Maitz, Manfred F.; Wang, Kebing; Shang, Tengda; Dai, Sheng; Fu, Yudie; Zhao, Yuancong; Yang, Zhilu; Wang, Jin; Li, XinMany polyurethanes (PUs) are blood-contacting materials due to their good mechanical properties, fatigue resistance, cytocompatibility, biosafety, and relatively good hemocompatibility. Further functionalization of the PUs using chemical synthetic methods is especially attractive for expanding their applications. Herein, a series of catechol functionalized PU (CPU-PTMEG) elastomers containing variable molecular weight of polytetramethylene ether glycol (PTMEG) soft segment are reported by stepwise polymerization and further introduction of catechol. Tailoring the molecular weight of PTMEG fragment enables a regulable catechol content, mobility of the chain segment, hydrogen bond and microphase separation of the C-PU-PTMEG elastomers, thus offering tunability of mechanical strength (such as breaking strength from 1.3 MPa to 5.7 MPa), adhesion, self-healing efficiency (from 14.9% to 96.7% within 2 hours), anticoagulant, antioxidation, anti-inflammatory properties and cellular growth behavior. As cardiovascular stent coatings, the C-PU-PTMEGs demonstrate enough flexibility to withstand deformation during the balloon dilation procedure. Of special importance is that the C-PU-PTMEG-coated surfaces show the ability to rapidly scavenge free radicals to maintain normal growth of endothelial cells, inhibit smooth muscle cell proliferation, mediate inflammatory response, and reduce thrombus formation. With the universality of surface adhesion and tunable multifunctionality, these novel C-PU-PTMEG elastomers should find potential usage in artificial heart valves and surface engineering of stents.
- ItemApplications of synthetic polymers in clinical medicine([Stevenage] : IET, 2015) Maitz, Manfred F.Multiple biological, synthetic and hybrid polymers are used for multiple medical applications. A wide range of different polymers is available, and they have further the advantage to be tunable in physical, chemical and biological properties in a wide range to match the requirements of specific applications. This review gives a brief overview about the introduction and developments of polymers in medicine in general, addressing first stable polymers, then polymers with degradability as a first biological function, followed by various other functional and responsive polymers. It is shown up that biomedical polymers comprise not only bulk materials, but also coatings and pharmaceutical nano-carriers for drugs. There is subsequently an overview of the most frequently used polymer classes. The main body of the review then is structured according to the medical applications, where key requirements of the applications and the currently used polymer solutions are indicated.
- ItemBio-responsive polymer hydrogels homeostatically regulate blood coagulation(London : Nature Publishing Group, 2013) Maitz, Manfred F.; Freudenberg, U.; Tsurkan, M.V.; Fischer, M.; Beyrich, T.; Werner, C.Bio-responsive polymer architectures can empower medical therapies by engaging molecular feedback-response mechanisms resembling the homeostatic adaptation of living tissues to varying environmental constraints. Here we show that a blood coagulation-responsive hydrogel system can deliver heparin in amounts triggered by the environmental levels of thrombin, the key enzyme of the coagulation cascade, which - in turn - becomes inactivated due to released heparin. The bio-responsive hydrogel quantitatively quenches blood coagulation over several hours in the presence of pro-coagulant stimuli and during repeated incubation with fresh, non-anticoagulated blood. These features enable the introduced material to provide sustainable, autoregulated anticoagulation, addressing a key challenge of many medical therapies. Beyond that, the explored concept may facilitate the development of materials that allow the effective and controlled application of drugs and biomolecules.
- ItemBiocompatibility assessment of silk nanoparticles: hemocompatibility and internalization by human blood cells(New York, NY : Elsevier, 2017) Maitz, Manfred F.; Sperling, Claudia; Wongpinyochit, Thidarat; Herklotz, Manuela; Werner, Carsten; Seib, F. PhilippMany nanoparticles are designed for use as potential nanomedicines for parenteral administration. However, emerging evidence suggests that hemocompatibility is important, but is highly particle- and test-bed dependent. Thus, knowledge of bulk material properties does not predict the hemocompatibility of uncharacterized nanoparticles, including silk nanoparticles. This study compares the hemocompatibility of silk versus silica nanoparticles, using whole human blood under quasi-static and flow conditions. Substantial hemocompatibility differences are noted for some nanoparticles in quasi-static versus dynamic studies; i.e., the inflammatory response to silk nanoparticles is significantly lower under flow versus quasi-static conditions. Silk nanoparticles also have very low coagulant properties - an observation that scales from the macro- to the nano-level. These nanoparticle hemocompatibility studies are complemented by preliminary live cell measurements to evaluate the endocytosis and trafficking of nanoparticles in human blood cells. Overall, this study demonstrates that nanoparticle hemocompatibility is affected by several factors, including the test bed design.
- ItemA “built-up” composite film with synergistic functionalities on Mg–2Zn–1Mn bioresorbable stents improves corrosion control effects and biocompatibility([Bejing] : KeAi Publishing, 2023) Dou, Zhenglong; Chen, Shuiling; Wang, Jiacheng; Xia, Li; Maitz, Manfred F.; Tu, Qiufen; Zhang, Wentai; Yang, Zhilu; Huang, NanControl of premature corrosion of magnesium (Mg) alloy bioresorbable stents (BRS) is frequently achieved by the addition of rare earth elements. However, limited long-term experience with these elements causes concerns for clinical application and alternative methods of corrosion control are sought after. Herein, we report a “built-up” composite film consisting of a bottom layer of MgF2 conversion coating, a sandwich layer of a poly (1, 3-trimethylene carbonate) (PTMC) and 3-aminopropyl triethoxysilane (APTES) co-spray coating (PA) and on top a layer of poly (lactic-co-glycolic acid) (PLGA) ultrasonic spray coating to decorate the rare earth element-free Mg–2Zn–1Mn (ZM21) BRS for tailoring both corrosion resistance and biological functions. The developed “built-up” composite film shows synergistic functionalities, allowing the compression and expansion of the coated ZM21 BRS on an angioplasty balloon without cracking or peeling. Of special importance is that the synergistic corrosion control effects of the “built-up” composite film allow for maintaining the mechanical integrity of stents for up to 3 months, where complete biodegradation and no foreign matter residue were observed about half a year after implantation in rabbit iliac arteries. Moreover, the functionalized ZM21 BRS accomplished re-endothelialization within one month.
- ItemCatechol-chitosan/polyacrylamide hydrogel wound dressing for regulating local inflammation(Amsterdam : Elsevier, 2022) Lu, Bingyang; Han, Xiao; Zou, Dan; Luo, Xiao; Liu, Li; Wang, Jingyue; Maitz, Manfred F.; Yang, Ping; Huang, Nan; Zhao, AnshaChronic wounds and the accompanying inflammation are ongoing challenges in clinical treatment. They are usually accompanied by low pH and high oxidative stress environments, limiting cell growth and proliferation. Ordinary medical gauze has limited therapeutic effects on chronic wounds, and there is active research to develop new wound dressings. The chitosan hydrogel could be widely used in biomedical science with great biocompatibility, but the low mechanical properties limit its development. This work uses polyacrylamide to prepare double-network (DN) hydrogels based on bioadhesive catechol-chitosan hydrogels. Cystamine and N, N′-Bis(acryloyl)cystamine, which can be cross-linking agents with disulfide bonds to prepare redox-responsive DN hydrogels and pH-responsive nanoparticles (NPs) prepared by acetalized cyclodextrin (ACD) are used to intelligently release drugs against chronic inflammation microenvironments. The addition of catechol groups and ACD-NPs loaded with the Resolvin E1 (RvE1), promotes cell adhesion and regulates the inflammatory response at the wound site. The preparation of the DN hydrogel in this study can be used to treat and regulate the inflammatory microenvironment of chronic wounds accurately. It provides new ideas for using inflammation resolving factor loaded in DN hydrogel of good biocompatibility with enhanced mechanical properties to intelligent regulate the wound inflammation and promote the wound repaired.
- ItemControlled synthesis of mussel-inspired Ag nanoparticle coatings with demonstrated in vitro and in vivo antibacterial properties(Amsterdam [u.a.] : Elsevier Science, 2021) Wang, Xiaowei; Xu, Kehui; Cui, Wendi; Yang, Xi; Maitz, Manfred F.; Li, Wei; Li, Xiangyang; Chen, JialongThe in-situ formation of silver nanoparticles (AgNPs) via dopamine-reduction of Ag+ has been widely utilized for titanium implants to introduce antibacterial properties. In previous studies, the preparation of AgNPs has focused on controlling the feeding concentrations, while the pH of the reaction solution was ignored. Herein, we systematically determined the influence of various pH (4, 7, 10) and Ag+ concentrations (0.01, 0.1 mg/mL) on the AgNPs formation, followed by the evaluation of the antibacterial properties in vitro and in vivo. The results revealed that an alkaline environment was favourable for AgNP formation and resulted in more particles. Although the AgNPs bearing Ti had lower biocompatibilities, it was significantly improved after 7 days of mineralization in simulated body fluid. The outstanding antibacterial property of the AgNPs was well maintained after one day and seven days of implantation. Moreover, 3D micro-CT modelling showed that the pH 10/0.1 group exhibited remarkable osteogenesis, which may be due to their strong antibacterial properties and ability to promote mineralization. Therefore, we have demonstrated that the solution pH was as important as the feeding Ag+ concentration in determining AgNP formation, and it has paved the way for developing various AgNP-loaded surfaces that could meet different antibacterial needs.
- ItemCorrigendum to "A Versatile Surface Bioengineering Strategy Based on Mussel-Inspired and Bioclickable Peptide Mimic"([Beijing] : China Association for Science and Technology, 2021) Xiao, Yu; Wang, Wenxuan; Tian, Xiaohua; Tan, Xing; Yang, Tong; Gao, Peng; Xiong, Kaiqing; Tu, Qiufen; Wang, Miao; Maitz, Manfred F.; Huang, Nan; Pan, Guoqing; Yang, Zhilu[This corrects the article DOI: 10.34133/2020/7236946.].
- ItemCurrent status of research and application in vascular stents(Beijing, China : Chinese Acad. of Sciences, 2013) Qi, P.K.; Yang, Y.; Maitz, Manfred F.; Huang, N.Cardiovascular diseases have been the leading cause of death in modern society. Using vascular stents to treat these coronary and peripheral artery diseases has been one of the most effective and rapidly adopted medical interventions. During the twenty-five years' development of vascular stents, revolutionary cardiovascular stents like drug eluting stents and endothelial progenitor cells capture stents have emerged. In this review, the evolution of vascular stents is summarized, aiming to provide a glimpse into the future of vascular stents. Advanced designs, focusing on the investigations of new substrates, new platforms, new drugs and new biomolecules are currently under evaluation with promising clinical studies. The concept of "time sequence functional stent" has been raised in this paper. It presents anti-proliferative properties in the first phase after implantation and subsequently support endothelialization. It also shows long-term inertness without release of toxic ions or toxic degradation products. The success of this concept is briefly presented with a clinical study in this model stents.
- ItemDiscovery of hemocompatible bacterial biofilm-resistant copolymers(Amsterdam [u.a.] : Elsevier Science, 2020) Singh, Taranjit; Hook, Andrew L.; Luckett, Jeni; Maitz, Manfred F.; Sperling, Claudia; Werner, Carsten; Davies, Martyn C.; Irvine, Derek J.; Williams, Paul; Alexander, R.Blood-contacting medical devices play an important role within healthcare and are required to be biocompatible, hemocompatible and resistant to microbial colonization. Here we describe a high throughput screen for copolymers with these specific properties. A series of weakly amphiphilic monomers are combinatorially polymerized with acrylate glycol monomers of varying chain lengths to create a library of 645 multi-functional candidate materials containing multiple chemical moieties that impart anti-biofilm, hemo- and immuno-compatible properties. These materials are screened in over 15,000 individual biological assays, targeting two bacterial species, one Gram negative (Pseudomonas aeruginosa) and one Gram positive (Staphylococcus aureus) commonly associated with central venous catheter infections, using 5 different measures of hemocompatibility and 6 measures of immunocompatibililty. Selected copolymers reduce platelet activation, platelet loss and leukocyte activation compared with the standard comparator PTFE as well as reducing bacterial biofilm formation in vitro by more than 82% compared with silicone. Poly(isobornyl acrylate-co-triethylene glycol methacrylate) (75:25) is identified as the optimal material across all these measures reducing P. aeruginosa biofilm formation by up to 86% in vivo in a murine foreign body infection model compared with uncoated silicone. © 2020 The Authors
- ItemDurable endothelium-mimicking coating for surface bioengineering cardiovascular stents([Bejing] : KeAi Publishing, 2021) Ma, Qing; Shi, Xiuying; Tan, Xing; Wang, Rui; Xiong, Kaiqin; Maitz, Manfred F.; Cui, Yuanyuan; Hu, Zhangmei; Tu, Qiufen; Huang, Nan; Shen, Li; Yang, ZhiluMimicking the nitric oxide (NO)-release and glycocalyx functions of native vascular endothelium on cardiovascular stent surfaces has been demonstrated to reduce in-stent restenosis (ISR) effectively. However, the practical performance of such an endothelium-mimicking surfaces is strictly limited by the durability of both NO release and bioactivity of the glycocalyx component. Herein, we present a mussel-inspired amine-bearing adhesive coating able to firmly tether the NO-generating species (e.g., Cu-DOTA coordination complex) and glycocalyx-like component (e.g., heparin) to create a durable endothelium-mimicking surface. The stent surface was firstly coated with polydopamine (pDA), followed by a surface chemical cross-link with polyamine (pAM) to form a durable pAMDA coating. Using a stepwise grafting strategy, Cu-DOTA and heparin were covalently grafted on the pAMDA-coated stent based on carbodiimide chemistry. Owing to both the high chemical stability of the pAMDA coating and covalent immobilization manner of the molecules, this proposed strategy could provide 62.4% bioactivity retention ratio of heparin, meanwhile persistently generate NO at physiological level from 5.9 ± 0.3 to 4.8 ± 0.4 × 10−10 mol cm−2 min−1 in 1 month. As a result, the functionalized vascular stent showed long-term endothelium-mimicking physiological effects on inhibition of thrombosis, inflammation, and intimal hyperplasia, enhanced re-endothelialization, and hence efficiently reduced ISR.
- ItemEndothelium-Mimicking Multifunctional Coating Modified Cardiovascular Stents via a Stepwise Metal-Catechol-(Amine) Surface Engineering Strategy(Washington, DC [u.a.] : American Association for the Advancement of Science, 2020) Yang, Ying; Gao, Peng; Wang, Juan; Tu, Qiufen; Bai, Long; Xiong, Kaiqin; Qiu, Hua; Zhao, Xin; Maitz, Manfred F.; Wang, Huaiyu; Li, Xiangyang; Zhao, Qiang; Xiao, Yin; Huang, Nan; Yang, ZhiluStenting is currently the major therapeutic treatment for cardiovascular diseases. However, the nonbiogenic metal stents are inclined to trigger a cascade of cellular and molecular events including inflammatory response, thrombogenic reactions, smooth muscle cell hyperproliferation accompanied by the delayed arterial healing, and poor reendothelialization, thus leading to restenosis along with late stent thrombosis. To address prevalence critical problems, we present an endothelium-mimicking coating capable of rapid regeneration of a competently functioning new endothelial layer on stents through a stepwise metal (copper)-catechol-(amine) (MCA) surface chemistry strategy, leading to combinatorial endothelium-like functions with glutathione peroxidase-like catalytic activity and surface heparinization. Apart from the stable nitric oxide (NO) generating rate at the physiological level (2:2 × 10a'10 mol/cm2/min lasting for 60 days), this proposed strategy could also generate abundant amine groups for allowing a high heparin conjugation efficacy up to ∼1 μg/cm2, which is considerably higher than most of the conventional heparinized surfaces. The resultant coating could create an ideal microenvironment for bringing in enhanced antithrombogenicity, anti-inflammation, anti-proliferation of smooth muscle cells, re-endothelialization by regulating relevant gene expressions, hence preventing restenosis in vivo. We envision that the stepwise MCA coating strategy would facilitate the surface endothelium-mimicking engineering of vascular stents and be therefore helpful in the clinic to reduce complications associated with stenosis. © 2020 American Association for the Advancement of Science. All rights reserved.
- ItemThe innate immune response of self-assembling silk fibroin hydrogels(Cambridge : Royal Soc. of Chemistry, 2021) Gorenkova, Natalia; Maitz, Manfred F.; Böhme, Georg; Alhadrami, Hani A.; Jiffri, Essam H.; Totten, John D.; Werner, Carsten; Carswell, Hilary V. O.; Seib, F. PhilippSilk has a long track record of use in humans, and recent advances in silk fibroin processing have opened up new material formats. However, these new formats and their applications have subsequently created a need to ascertain their biocompatibility. Therefore, the present aim was to quantify the haemocompatibility and inflammatory response of silk fibroin hydrogels. This work demonstrated that self-assembled silk fibroin hydrogels, as one of the most clinically relevant new formats, induced very low blood coagulation and platelet activation but elevated the inflammatory response of human whole blood in vitro. In vivo bioluminescence imaging of neutrophils and macrophages showed an acute, but mild, local inflammatory response which was lower than or similar to that induced by polyethylene glycol, a benchmark material. The time-dependent local immune response in vivo was corroborated by histology, immunofluorescence and murine whole blood analyses. Overall, this study confirms that silk fibroin hydrogels induce a similar immune response to that of PEG hydrogels, while also demonstrating the power of non-invasive bioluminescence imaging for monitoring tissue responses. This journal is
- ItemIntelligent H2S release coating for regulating vascular remodeling(Bejing : KeAi Publishing, 2021) Lu, Bingyang; Han, Xiao; Zhao, Ansha; Luo, Dan; Maitz, Manfred F.; Wang, Haohao; Yang, Ping; Huang, NanCoronary atherosclerotic lesions exhibit a low-pH chronic inflammatory response. Due to insufficient drug release control, drug-eluting stent intervention can lead to delayed endothelialization, advanced thrombosis, and unprecise treatment. In this study, hyaluronic acid and chitosan were used to prepare pH-responsive self-assembling films. The hydrogen sulfide (H2S) releasing aspirin derivative ACS14 was used as drug in the film. The film regulates the release of the drug adjusted to the microenvironment of the lesion, and the drug balances the vascular function by releasing the regulating gas H2S, which comparably to NO promotes the self-healing capacity of blood vessels. Drug releasing profiles of the films at different pH, and other biological effects on blood vessels were evaluated through blood compatibility, cellular, and implantation experiments. This novel method of self-assembled films which H2S in an amount, which is adjusted to the condition of the lesion provides a new concept for the treatment of cardiovascular diseases.
- ItemA modular in vitro flow model to analyse blood-surface interactions under physiological conditions(Berlin : De Gruyter, 2021) Valtin, Juliane; Behrens, Stephan; Maitz, Manfred F.; Schmieder, Florian; Sonntag, Frank; Werner, CarstenNewly developed materials for blood-contacting devices need to undergo hemocompatibility testing to prove compliance with clinical requirements. However, many current in vitro models disregard the influence of flow conditions and blood exchange as it occurs in vivo. Here, we present a flow model which allows testing of blood-surface interactions under more physiological conditions. This modular platform consists of a triple-pump-chip and a microchannel-chip with a customizable surface. Flow conditions can be adjusted individually within the physiological range. A performance test with whole blood confirmed the hemocompatibility of our modular platform. Hemolysis was negligible, inflammation and hemostasis parameters were comparable to those detected in a previously established quasi-static whole blood screening chamber. The steady supply of fresh blood avoids secondary effects by nonphysiological accumulation of activation products. Experiments with three subsequently tested biomaterials showed results similar to literature and our own experience. The reported results suggest that our developed flow model allows the evaluation of blood-contacting materials under physiological flow conditions. By adjusting the occurring wall shear stress, the model can be adapted for selected test conditions.
- ItemNano-biosupercapacitors enable autarkic sensor operation in blood([London] : Nature Publishing Group UK, 2021) Lee, Yeji; Bandari, Vineeth Kumar; Li, Zhe; Medina-Sánchez, Mariana; Maitz, Manfred F.; Karnaushenko, Daniil; Tsurkan, Mikhail V; Karnaushenko, Dmitriy D.; Schmidt, Oliver G.Today’s smallest energy storage devices for in-vivo applications are larger than 3 mm3 and lack the ability to continuously drive the complex functions of smart dust electronic and microrobotic systems. Here, we create a tubular biosupercapacitor occupying a mere volume of 1/1000 mm3 (=1 nanoliter), yet delivering up to 1.6 V in blood. The tubular geometry of this nano-biosupercapacitor provides efficient self-protection against external forces from pulsating blood or muscle contraction. Redox enzymes and living cells, naturally present in blood boost the performance of the device by 40% and help to solve the self-discharging problem persistently encountered by miniaturized supercapacitors. At full capacity, the nano-biosupercapacitors drive a complex integrated sensor system to measure the pH-value in blood. This demonstration opens up opportunities for next generation intravascular implants and microrobotic systems operating in hard-to-reach small spaces deep inside the human body.
- ItemPhoto-functionalized TiO2 nanotubes decorated with multifunctional Ag nanoparticles for enhanced vascular biocompatibility(Bejing : KeAi Publishing, 2021) Chen, Jiang; Dai, Sheng; Liu, Luying; Maitz, Manfred F.; Liao, Yuzhen; Cui, Jiawei; Zhao, Ansha; Yang, Ping; Huang, Nan; Wang, YunbingTitanium dioxide (TiO2) has a long history of application in blood contact materials, but it often suffers from insufficient anticoagulant properties. Recently, we have revealed the photocatalytic effect of TiO2 also induces anticoagulant properties. However, for long-term vascular implant devices such as vascular stents, besides anticoagulation, also anti-inflammatory, anti-hyperplastic properties, and the ability to support endothelial repair, are desired. To meet these requirements, here, we immobilized silver nanoparticles (AgNPs) on the surface of TiO2 nanotubes (TiO2-NTs) to obtain a composite material with enhanced photo-induced anticoagulant property and improvement of the other requested properties. The photo-functionalized TiO2-NTs showed protein-fouling resistance, causing the anticoagulant property and the ability to suppress cell adhesion. The immobilized AgNPs increased the photocatalytic activity of TiO2-NTs to enhances its photo-induced anticoagulant property. The AgNP density was optimized to endow the TiO2-NTs with anti-inflammatory property, a strong inhibitory effect on smooth muscle cells (SMCs), and low toxicity to endothelial cells (ECs). The in vivo test indicated that the photofunctionalized composite material achieved outstanding biocompatibility in vasculature via the synergy of photo-functionalized TiO2-NTs and the multifunctional AgNPs, and therefore has enormous potential in the field of cardiovascular implant devices. Our research could be a useful reference for further designing of multifunctional TiO2 materials with high vascular biocompatibility.
- ItemPlatelet Membrane-Coated Nanocarriers Targeting Plaques to Deliver Anti-CD47 Antibody for Atherosclerotic Therapy([Beijing] : China Association for Science and Technology, 2022) Chen, Liang; Zhou, Zhongyi; Hu, Cheng; Maitz, Manfred F.; Yang, Li; Luo, Rifang; Wang, YunbingAtherosclerosis, the principle cause of cardiovascular disease (CVD) worldwide, is mainly characterized by the pathological accumulation of diseased vascular cells and apoptotic cellular debris. Atherogenesis is associated with the upregulation of CD47, a key antiphagocytic molecule that is known to render malignant cells resistant to programmed cell removal, or "efferocytosis." Here, we have developed platelet membrane-coated mesoporous silicon nanoparticles (PMSN) as a drug delivery system to target atherosclerotic plaques with the delivery of an anti-CD47 antibody. Briefly, the cell membrane coat prolonged the circulation of the particles by evading the immune recognition and provided an affinity to plaques and atherosclerotic sites. The anti-CD47 antibody then normalized the clearance of diseased vascular tissue and further ameliorated atherosclerosis by blocking CD47. In an atherosclerosis model established in ApoE-/- mice, PMSN encapsulating anti-CD47 antibody delivery significantly promoted the efferocytosis of necrotic cells in plaques. Clearing the necrotic cells greatly reduced the atherosclerotic plaque area and stabilized the plaques reducing the risk of plaque rupture and advanced thrombosis. Overall, this study demonstrated the therapeutic advantages of PMSN encapsulating anti-CD47 antibodies for atherosclerosis therapy, which holds considerable promise as a new targeted drug delivery platform for efficient therapy of atherosclerosis.
- ItemPoly(2-alkyl-2-oxazoline)-Heparin Hydrogels—Expanding the Physicochemical Parameter Space of Biohybrid Materials(Weinheim : Wiley-VCH, 2021) Hahn, Dominik; Sonntag, Jannick M.; Lück, Steffen; Maitz, Manfred F.; Freudenberg, Uwe; Jordan, Rainer; Werner, CarstenPoly(ethylene glycol) (PEG)-glycosaminoglycan (GAG) hydrogel networks are established as very versatile biomaterials. Herein, the synthetic gel component of the biohybrid materials is systematically varied by combining different poly(2-alkyl-2-oxazolines) (POx) with heparin applying a Michael-type addition crosslinking scheme: POx of gradated hydrophilicity and temperature-responsiveness provides polymer networks of distinctly different stiffness and swelling. Adjusting the mechanical properties and the GAG concentration of the gels to similar values allows for modulating the release of GAG-binding growth factors (VEGF165 and PDGF-BB) by the choice of the POx and its temperature-dependent conformation. Adsorption of fibronectin, growth of fibroblasts, and bacterial adhesion scale with the hydrophobicity of the gel-incorporated POx. In vitro hemocompatibility tests with freshly drawn human whole blood show advantages of POx-based gels compared to the PEG-based reference materials. Biohybrid POx hydrogels can therefore enable biomedical technologies requiring GAG-based materials with customized and switchable physicochemical characteristics. © 2021 The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH.
- ItemReal-Time Monitoring of Blood Parameters in the Intensive Care Unit: State-of-the-Art and Perspectives(Basel : MDPI, 2022) Bockholt, Rebecca; Paschke, Shaleen; Heubner, Lars; Ibarlucea, Bergoi; Laupp, Alexander; Janićijević, Željko; Klinghammer, Stephanie; Balakin, Sascha; Maitz, Manfred F.; Werner, Carsten; Cuniberti, Gianaurelio; Baraban, Larysa; Spieth, Peter MarkusThe number of patients in intensive care units has increased over the past years. Critically ill patients are treated with a real time support of the instruments that offer monitoring of relevant blood parameters. These parameters include blood gases, lactate, and glucose, as well as pH and tem-perature. Considering the COVID-19 pandemic, continuous management of dynamic deteriorating parameters in patients is more relevant than ever before. This narrative review aims to summarize the currently available literature regarding real-time monitoring of blood parameters in intensive care. Both, invasive and non-invasive methods are described in detail and discussed in terms of general advantages and disadvantages particularly in context of their use in different medical fields but especially in critical care. The objective is to explicate both, well-known and frequently used as well as relatively unknown devices. Furtehrmore, potential future direction in research and development of realtime sensor systems are discussed. Therefore, the discussion section provides a brief description of current developments in biosensing with special emphasis on their technical implementation. In connection with these developments, the authors focus on different electrochemical approaches to invasive and non-invasive measurements in vivo.