Karen M Haberstroh

Brown University, Providence, Rhode Island, United States

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Publications (60)157.72 Total impact

  • Young Wook Chun · Hojean Lim · Thomas J Webster · Karen M Haberstroh ·
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    ABSTRACT: The interaction between cells or tissues and natural or synthetic materials which mimic the natural biological environment has been a matter of great interest in tissue engineering. In particular, surface properties of biomaterials (regardless of whether they are natural or synthetic) have been optimized using nanotechnology to improve interactions with cells for regenerative medicine applications. Specifically, in vivo and in vitro studies have demonstrated greater bladder tissue growth on polymeric surfaces with nanoscale to submicron surface features. Improved bladder cell responses on nanostructured polymers have been correlated to unique nanomaterial surface features leading to greater surface energy which influences initial protein interactions. Moreover, coupled with the observed greater in vitro and in vivo bladder cell adhesion as well as proliferation on nanostructured compared to conventional synthetic polymers, decreased calcium stone formation has also been measured. In this article, the importance of nanostructured biomaterial surface features for bladder tissue replacements are reviewed with thoughts on future directions for this emerging field. WIREs Nanomed Nanobiotechnol 2011 3 134–145 DOI: 10.1002/wnan.89 For further resources related to this article, please visit the WIREs website
    Wiley Interdisciplinary Reviews Nanomedicine and Nanobiotechnology 03/2011; 3(2). DOI:10.1002/wnan.89 · 4.49 Impact Factor
  • Rachel L. Price · Kathy L. Elias · Karen M. Haberstroh · Thomas J. Webster ·
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    ABSTRACT: The objective of the present in vitro study was to investigate the potential of carbon nanofibers, which have nanometer dimensions similar to hydroxyapatite crystals in physiological bone, for orthopedic applications. Studies of alkaline phosphatase activity and calcium deposition by osteoblasts (the bone-synthesizing cells) were performed on both nanophase (less than 100 nm) and conventional (greater than 100 nm) diameter carbon nanofibers. Results provided the first evidence of a strong correlation between decreased carbon fiber diameter and both increased alkaline phosphatase activity and increased calcium deposition by osteoblasts at early time points (specifically, 7 days), but not at later time points (specifically, 14 and 21 days). Results of early calcium deposition by osteoblasts on carbon nanofibers are promising and consistent with the desired rapid formation of natural bone at the implant interface.
    MRS Online Proceeding Library 01/2011; 711. DOI:10.1557/PROC-711-HH3.11.1
  • Rachel L. Price · Karen M. Haberstroh · Thomas J. Webster ·
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    ABSTRACT: Osteoblast (the bone-forming cells) and smooth muscle cell adhesion was investigated on carbon nanofiber formulations of various diameters (specifically, from 60 to 200 nm) and surface energies (from 25 to 140 mJ/m2) in the present in vitro study. Results provided the first evidence that osteoblast adhesion increased with decreased carbon nanofiber diameter after 1 hour. In contrast, smooth muscle cell adhesion was not dependent on carbon nanofiber diameter. Moreover, the present study demonstrated that smooth muscle cell adhesion decreased with increased carbon nanofiber surface energy after 1 hour. Alternatively, osteoblast adhesion was not affected by carbon nanofiber surface energy. Since adhesion is a crucial prerequisite for subsequent functions of cells (such as the deposition of bone by osteoblasts), the present results of controlled adhesion of both osteoblasts and a competitive cell line (i.e., smooth muscle cells) demonstrate that carbon nanofibers with small diameters and high surface energies may become the next-generation of orthopedic implant materials to enhance new bone synthesis. These criteria may prove critical in the clinical success of bone prostheses.
    MRS Online Proceeding Library 01/2011; 676. DOI:10.1557/PROC-676-Y9.7
  • Alissa L. Russ · David E. Anderson · Jason J. McGill · Karen M. Haberstroh · Ann E. Rundell ·
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    ABSTRACT: In ischemic tissues, oxygen (O2) and glucose become depleted while cells concomitantly promote carbon dioxide (CO2) and waste accumulation. Hypoxia has become a topic of great interest. Notably, these insults, including hypoxia, do not exist in isolation during ischemia in vivo; their simultaneous presence may influence pathological mechanisms. We hypothesized that low O2 (hypoxia), elevated CO2 (hypercapnia), and glucose deprivation each have a statistically significant main effect and interact in a non-additive manner, leading to decreased cellular proliferation and altered (i.e., increased) morphological measurements. Renal LLC-PK1 cells were subjected to: (i) hypoxia (<0.01%O2/5%CO2); (ii) hypercapnia (20%O2/20%CO2); or (iii) hypoxia+hypercapnia (<0.01%O2/20%CO2). Two levels of media glucose were used to investigate glucose depletion. Additionally, a recovery period was simulated with and without fresh media to explore post-insult reperfusion responses. Statistical analyses identified significant main effects and insult interactions. Several interactions occurred between hypoxia, hypercapnia, and/or glucose, thereby producing decreased cellular proliferation and atypical morphologies. Hypoxia-induced changes in proliferation were moderated by hypercapnia. Moreover, reoxygenation and nutrient replenishment were essential to increase cell density during simulated post-ischemia reperfusion. Multiple insults may exert main effects and interact during ischemia-induced morphological and proliferative changes. To promote clinical relevance, future studies targeting ischemic mechanisms should examine multiple insults and consider the implications of insult interactions. KeywordsLLC-PK1-Kidney-Reperfusion-Oxygen-Carbon dioxide-Cell dimensions
    Cellular and Molecular Bioengineering 06/2009; 3(2):171-186. DOI:10.1007/s12195-009-0098-y · 1.32 Impact Factor
  • Alissa L Russ · Iunia A Dadarlat · Karen M Haberstroh · Ann E Rundell ·
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    ABSTRACT: Obstructive uropathy can cause irreversible renal damage. It has been hypothesized that elevated hydrostatic pressure within renal tubules and/or renal ischemia contributes to cellular injury following obstruction. However, these assaults are essentially impossible to isolate in vivo. Therefore, we developed a novel pressure system to evaluate the isolated and coordinated effects of elevated hydrostatic pressure and ischemic insults on renal cells in vitro. Cells were subjected to: (1) elevated hydrostatic pressure (80 cm H(2)O); (2) ischemic insults (hypoxia (0% O(2)), hypercapnia (20% CO(2)), and 0 mM glucose media); and (3) elevated pressure + ischemic insults. Cellular responses including cell density, lactate dehydrogenase (LDH) release, and intracellular LDH (LDH(i)), were recorded after 24 h of insult and following recovery. Data were analyzed to assess the primary effects of ischemic insults and elevated pressure. Unlike pressure, ischemic insults exerted a primary effect on nearly all response measurements. We also evaluated the data for insult interactions and identified significant interactions between ischemic insults and pressure. Altogether, findings indicate that pressure may sub-lethally effect cells and alter cellular metabolism (LDH(i)) and membrane properties. Results suggest that renal ischemia may be the primary, but not the sole, cause of cellular injury induced by obstructive uropathy.
    Annals of Biomedical Engineering 05/2009; 37(7):1415-24. DOI:10.1007/s10439-009-9695-0 · 3.23 Impact Factor
  • Young Wook Chun · Dongwoo Khang · Karen M Haberstroh · Thomas J Webster ·
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    ABSTRACT: Synthetic polymers have been proposed for replacing resected cancerous bladder tissue. However, conventional (or nanosmooth) polymers used in such applications (such as poly(ether) urethane (PU) and poly-lactic-co-glycolic acid (PLGA)) often fail clinically due to poor bladder tissue regeneration, low cytocompatibility properties, and excessive calcium stone formation. For the successful reconstruction of bladder tissue, polymer surfaces should be modified to combat these common problems. Along these lines, implementing nanoscale surface features that mimic the natural roughness of bladder tissue on polymer surfaces can promote appropriate cell growth, accelerate bladder tissue regeneration and inhibit bladder calcium stone formation. To test this hypothesis, in this study, the cytocompatibility properties of both a non-biodegradable polymer (PU) and a biodegradable polymer (PLGA) were investigated after etching in chemicals (HNO(3) and NaOH, respectively) to create nanoscale surface features. After chemical etching, PU possessed submicron sized pores and numerous nanometer surface features while PLGA possessed few pores and large amounts of nanometer surface roughness. Results from this study strongly supported the assertion that nanometer scale surface roughness produced on PU and PLGA promoted the density of urothelial cells (cells that line the interior of the bladder), with the greatest urothelial cell densities observed on nanorough PLGA. In addition, compared to respective conventional polymers, the results provided evidence that nanorough PU and PLGA inhibited calcium oxalate stone formation; submicron pored nanorough PU inhibited calcium oxalate stone formation the most. Thus, results from the present study suggest the importance of nanometer topographical cues for designing better materials for bladder tissue engineering applications.
    Nanotechnology 03/2009; 20(8):085104. DOI:10.1088/0957-4484/20/8/085104 · 3.82 Impact Factor
  • Dongwoo Khang · Jing Lu · Chang Yao · Karen M Haberstroh · Thomas J Webster ·
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    ABSTRACT: The quantified contribution of pure nanometer (features less than 100 nm in both the lateral and vertical scale) and sub-micron (features larger than 100 nm in the lateral scale) surface structures on the adhesion of vascular (endothelial) and bone (osteoblasts) cells were demonstrated in this study. Compared with flat titanium surfaces, sub-micron surface features led to a 27% increase in surface energy and promoted endothelial cell adhesion density by 200%. In addition, nanometer surface features also led to a 10% increase in surface energy and a 50% increase in endothelial cell adhesion density compared to flat titanium surfaces. Using aligned patterns of such features on titanium, it was clearly identified that both endothelial and bone cells selectively adhered onto sub-micron and nanometer surface features by 400% and 50% more than onto flat regions, respectively. Thus, the surface patterns developed in this study clearly confirmed that sub-micron to nanometer titanium surface features enhanced cytocompatibility properties for both endothelial and bone cells. Although sub-micron features on titanium had the highest surface energy and the greatest cell adhesion densities, nanometer surface features in this study were more efficient surface features increasing both surface energy and cell adhesion more with respect to smaller changes in surface area and surface roughness (compared to sub-micron surface features on titanium which had considerably larger changes in surface area and surface roughness).
    Biomaterials 04/2008; 29(8):970-83. DOI:10.1016/j.biomaterials.2007.11.009 · 8.56 Impact Factor
  • Alissa L Russ · Karen M Haberstroh · Ann E Rundell ·
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    ABSTRACT: Ischemia has elicited a great deal of interest among the scientific community due to its role in life-threatening pathologies such as cancer, stroke, acute renal failure, and myocardial infarction. Oxygen deprivation (hypoxia) associated with ischemia has recently become a subject of intense scrutiny. New investigators may find it challenging to induce hypoxic injury in vitro. Researchers may not always be aware of the experimental barriers that contribute to this phenomenon. Furthermore, ischemia is associated with other major insults, such as excess carbon dioxide (hypercapnia), nutrient deprivation, and accumulation of cellular wastes. Ideally, these conditions should also be incorporated into in vitro models. Therefore, the motivation behind this review is to: i. delineate major in vivo ischemic insults; ii. identify and explain critical in vitro parameters that need to be considered when simulating ischemic pathologies; iii. provide recommendations to improve experiments; and as a result, iv. enhance the validity of in vitro results for understanding clinical ischemic pathologies. Undoubtedly, it is not possible to completely replicate the in vivo environment in an ex vivo model system. In fact, the primary goal of many in vitro studies is to elucidate the role of specific stimuli during in vivo pathological events. This review will present methodologies that may be implemented to improve the applicability of in vitro models for understanding the complex pathological mechanisms of ischemia. Finally, although these topics will be discussed within the context of renal ischemia, many are pertinent for cellular models of other organ systems and pathologies.
    Experimental and Molecular Pathology 11/2007; 83(2):143-59. DOI:10.1016/j.yexmp.2007.03.002 · 2.71 Impact Factor
  • Saba Choudhary · Karen M Haberstroh · Thomas J Webster ·
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    ABSTRACT: Vascular tissue possesses numerous nanostructured surface features, but most metallic vascular stents proposed to restore blood flow are smooth at the nanoscale. Thus, the objective of the present study was to determine in vitro vascular cell functions on nanostructured titanium (Ti) compared to conventional commercially pure (c.p.) Ti. Results of this study showed for the first time greater competitive adhesion of endothelial versus vascular smooth muscle cells on nanostructured Ti compared to conventional Ti after 4 hours. Moreover, when cultured separately, increased endothelial and vascular smooth muscle cell density was observed on nanostructured Ti compared to conventional c.p. Ti after 1, 3, and 5 days; endothelial cells formed confluent monolayers before vascular smooth muscle cells on nanostructured Ti. Results also showed greater total amounts of collagen and elastin synthesis by vascular cells when cultured on nanostructured Ti. Since a major mode of failure of conventional vascular stents is the overgrowth of smooth muscle cells compared to endothelial cells, these results suggest that while the functions of both types of vascular cells were promoted on nanostructured c.p. Ti, endothelial cell functions (of particular importance, cell density or confluence) were enhanced over that of vascular smooth muscle cells. Thus, the present in vitro study showed that vascular stents composed of nanometer c.p. Ti particles may invoke advantageous cellular responses for improved stent applications.
    Tissue Engineering 08/2007; 13(7):1421-30. DOI:10.1089/ten.2006.0376 · 4.25 Impact Factor
  • Derick C Miller · Karen M Haberstroh · Thomas J Webster ·
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    ABSTRACT: The largest cause of mortality in the Western world is atherosclerotic vascular disease. Many of these diseases require synthetic vascular grafts; however, their patency rate is only 30% in small (<6 mm) diameter vascular grafts after 5 years of implantation. In an effort to increase small diameter vascular graft success, researchers have been designing random nanostructured surface features which enhance vascular cell functions. However, for the present study, highly-controllable, nanostructured features on poly(lactic-co-glycolic acid) (PLGA) surfaces were formulated. To create ordered nanostructured roughness on PLGA surfaces, either 500, 200, or 100 nm polystyrene nanospheres were separately placed onto mica. These were then used as a template for creating an inverse poly(dimethylsiloxane) mold which was utilized to cast PLGA. Compared to all other PLGA films formulated, AFM results demonstrated greater initial fibronectin spreading on PLGA which possessed spherical 200 nm features. Compared to smooth PLGA, PLGA with 500 or 100 nm surface features, results further showed that PLGA with 200 nm spherical features promoted vascular cell (specifically, endothelial, and smooth muscle cell) adhesion. In this manner, the present study demonstrated a specific nanometer surface feature size that promoted fibronectin spreading and subsequent vascular cell adhesion; criteria critical to vascular graft success.
    Journal of Biomedical Materials Research Part A 06/2007; 81(3):678-84. DOI:10.1002/jbm.a.31093 · 3.37 Impact Factor
  • Megan Pattison · Thomas J Webster · Jeffrey Leslie · Martin Kaefer · Karen M Haberstroh ·
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    ABSTRACT: Bladder cancers requiring radical cystectomy, along with congenital and acquired disorders which result in obstruction of the bladder, necessitate surgical measures (including augmentation); such diagnoses bring a clinical need for effective bladder replacement implant designs. Many recent approaches for the design of soft tissue replacement materials have relied on the use of synthetic polymeric substances; unfortunately, the optimal soft tissue implant material is yet to be found. This may, in part, be because current polymeric formulations fail to sufficiently biomimic the neighboring bladder tissue. This study took a brand new approach in designing the next generation of tissue-engineered bladder constructs through the use of nanotechnology, or materials with nanometer (less than 100 nm) surface features. Results provided evidence that nano-structured polymeric scaffolds (specifically, PLGA and PU) created using chemical etching techniques are capable of enhancing the human bladder smooth muscle cell adhesion, proliferation, and the production of extracellular matrix (ECM) proteins. Preliminary in vivo results also speak to the usefulness of such nano-structured materials. In combination, these findings suggest that nano-dimensional PLGA and PU scaffolds are promising replacement materials for the human bladder wall.
    Macromolecular Bioscience 05/2007; 7(5):690-700. DOI:10.1002/mabi.200600297 · 3.85 Impact Factor
  • Jennifer A. McCann-Brown · Thomas J. Webster · Karen M. Haberstroh ·
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    ABSTRACT: Arterial homeostasis is dictated by hemodynamics and intercellular communications. Therefore, the present study exposed vascular cells to mechanical forces and conditioned medium to determine the impact of intracellular communication on cell responses. Endothelial cells exposed to flow and flow-conditioned medium demonstrated the most significant up regulation of COX-2 ( p < 0.01), ecNOS ( p < 0.01), and PDGF-B ( p < 0.05) mRNA. When exposed to pressure and control medium, endothelial cells expressed COX-2 ( p < 0.01), ecNOS ( p < 0.01), and PDGF-B ( p < 0.01) mRNA to a lesser extent than cells exposed to flow and control medium. In addition, cell growth studies in the presence of flow- and pressure-conditioned medium revealed decreased ( p < 0.05) endothelial cell growth and increased ( p < 0.05) smooth muscle cell growth. Ultimately, understanding the effects of chemical mediators released by vascular cells under physiological and pathological conditions will aid in elucidating the development and progression of atherosclerosis.
    Chemical Engineering Communications 03/2007; 194(3):309-321. DOI:10.1080/00986440600829903 · 1.10 Impact Factor
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    Lester J Smith · John S Swaim · Chang Yao · Karen M Haberstroh · Eric A Nauman · Thomas J Webster ·
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    ABSTRACT: There are more than 30,000 orthopedic implant revision surgeries necessary each year in part due to poor implant fixation with juxtaposed bone. A further emphasis on the current problems associated with insufficient bone implant performance is the fact that many patients are receiving hip implants earlier in life, remaining active older, and that the human lifespan is continuously increasing. Collectively, it is clear that there is a strong clinical need to improve implant performance through proper, prolonged fixation. For these reasons, the objective of the present in vitro study was to improve the performance of titanium (Ti), one of the most popular orthopedic implant materials. Accordingly, the proliferative response of osteoblasts (bone-forming cells) on novel nanostructured Ti/PLGA (poly-lactic-co-glycolic acid) composites was examined. This study showed that nano-topography can be easily applied to Ti (through anodization) and porous PLGA (through NaOH chemical etching) to enhance osteoblast cell proliferation which may lead to better orthopedic implant performance. This straight forward application of nano-topography on current bone implant materials represents a new direction in the design of enhanced biomaterials for the orthopedic industry.
    International Journal of Nanomedicine 02/2007; 2(3):493-9. · 4.38 Impact Factor
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    Lester L Smith · Paul J Niziolek · Karen M Haberstroh · Eric A Nauman · Thomas J Webster ·
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    ABSTRACT: To facilitate locomotion and support the body, the skeleton relies on the transmission of forces between muscles and bones through complex junctions called entheses. The varying mechanical and biological properties of the enthesis make healing this avascular tissue difficult; hence the need for an engineered alternative. Cells in situ interact with their environment on the nano-scale which suggests that engineered approaches to enthesis regeneration should include such biologically-inspired nano-scale surface features. The present in vitro study investigated the effects of etching poly-lactic-co-glycolic acid (PLGA) scaffolds to produce nano-topography on the adhesion of fibroblasts and osteoblasts, two integral enthesis cell types. Nano-topography was produced on PLGA by etching the scaffolds in NaOH. Results showed that etching PLGA with NaOH to create nano-scale surface features decreased fibroblast adhesion while it increased osteoblast adhesion; criteria critical for the spatial control of osteoblast and fibroblast adhesion for a successful enthesis tissue engineering material. Thus, the results of this study showed for the first time collective evidence that PLGA can be either treated with NaOH or not on ends of an enthesis tissue engineering construct to spatially increase osteoblast and fibroblast adhesion, respectively.
    International Journal of Nanomedicine 02/2007; 2(3):383-8. · 4.38 Impact Factor
  • Karen M. Haberstroh · Megan A. Pattison · Martin Kaefer · Thomas J. Webster ·
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    ABSTRACT: Superficial bladder cancer is often treated by removing the cancerous portion of the bladder wall combined with immuno-chemotherapy; in more extreme cases, it is often necessary to remove the entire bladder wall. This diagnosis brings an obvious need for bladder tissue replacement designs with a high degree of efficacy. Since bladder cells are accustomed to interacting with extracellular matrix proteins having dimensions on the nanometer scale, this study aimed to design the next generation of tissue-engineered bladder replacement constructs with nanometer (less than 100 nm) surface features. For this purpose, porous and biodegradable PLGA and PU scaffolds were treated with various concentrations of NaOH or HNO3, respectively, for various periods of time to create nanometer surface roughness. Resulting surface properties were characterized using SEM (to visualize scaffold properties) and BET. Cell experiments conducted on these polymeric scaffolds provided evidence of enhanced bladder smooth muscle cell attachment, growth, and elastin/collagen production (critical extracellular matrix proteins in the bladder tissue regeneration process) as surface feature dimensions were reduced into the nanometer regime. In vivo augmentation surgeries with nano-structured PLGA and PU patches will provide further information regarding total bladder capacity, anastomotic integrity, burst pressure, epithelialization, muscular ingrowth, and neovascularization, In vitro and in vivo proof of material usefulness and technique would provide urologists with a readily accessible graft for bladder tissue replacement applications.
    Materials Science Forum 01/2007; 539-543:540-544. DOI:10.4028/www.scientific.net/MSF.539-543.540
  • Jennifer A. McCann · Thomas J. Webster · Karen M. Haberstroh ·
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    ABSTRACT: The development of several vascular diseases is linked to both blood flowproperties and cellular behavior in the arterial and venous systems. For instance, atherosclerosis development is dependent on the blood flow profile, shear stress rate, and resulting cellular responses in the arteries. Specifically, in regions of disturbed flow behavior, cells demonstrate both altered morphology and phenotype. Based on this clinical knowledge, in vitro fluid flow studies have been performed on vascular endothelial and smooth muscle cells to understand the process of disease initiation and development. Ultimately, results of such studies will provide knowledge regarding key pathways involved in disease progression. Moreover, this information will be critical when designing effective drug therapies in the clinical setting.
    12/2006: pages 371-394;
  • Karen M Haberstroh ·

    Nanomedicine 11/2006; 1(3):355-8. DOI:10.2217/17435889.1.3.355 · 5.41 Impact Factor
  • Megan A Pattison · Thomas J Webster · Karen M Haberstroh ·
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    ABSTRACT: Bladder wall resection is often required as a treatment for invasive bladder cancer. When this happens, a suitable replacement material is needed. The present study, therefore, created three-dimensional, porous, nano-structured poly(ether urethane) (PU) matrices for use as bladder tissue-engineering scaffolds. Select cytocompatibility experiments (specifically adhesion and long-term growth studies) were performed on these scaffolds using human bladder smooth muscle cells (BdSMCs). In addition, the amount of total collagen and elastin present in each cell-seeded scaffold was determined since the production of these extracellular matrix (ECM) proteins is essential for the health and survival of cells and for the functionality of the replaced organ. Finally, to better understand how these scaffolds and resident cells would perform in the complex mechanical environment of the bladder wall, scaffolds and cells were subjected to 10 cmH2O pressure using a computer-controlled pressure chamber. Results provided evidence that compared to conventionally used, micro-dimensional PU scaffolds, the novel, nanodimensional scaffolds created in this research increased cell adhesion, growth, and ECM protein production. Additionally, scaffolds and resident cells were not affected by exposure to 10 cmH2O pressure (compared to controls maintained under atmospheric conditions). These results are promising and provide evidence that the nano-dimensional PU scaffolds created in this research are suitable bladder replacement materials that may outperform materials currently used for such purposes.
    Journal of Biomaterials Science Polymer Edition 02/2006; 17(11):1317-32. DOI:10.1163/156856206778667460 · 1.65 Impact Factor
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    Saba Choudhary · Mikal Berhe · Karen M Haberstroh · Thomas J Webster ·
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    ABSTRACT: In the body, vascular cells continuously interact with tissues that possess nanostructured surface features due to the presence of proteins (such as collagen and elastin) embedded in the vascular wall. Despite this fact, vascular stents intended to restore blood flow do not have nanoscale surface features but rather are smooth at the nanoscale. As the first step towards creating the next generation of vascular stent materials, the objective of this in vitro study was to investigate vascular cell (specifically, endothelial, and vascular smooth muscle cell) adhesion on nanostructured compared with conventional commercially pure (cp) Ti and CoCrMo. Nanostructured cp Ti and CoCrMo compacts were created by separately utilizing either constituent cp Ti or CoCrMo nanoparticles as opposed to conventional micronsized particles. Results of this study showed for the first time increased endothelial and vascular smooth muscle cell adhesion on nanostructured compared with conventional cp Ti and CoCrMo after 4 hours’ adhesion. Moreover, compared with their respective conventional counterparts, the ratio of endothelial to vascular smooth muscle cells increased on nanostructured cp Ti and CoCrMo. In addition, endothelial and vascular smooth muscle cells had a better spread morphology on the nanostructured metals compared with conventional metals. Overall, vascular cell adhesion was better on CoCrMo than on cp Ti. Results of surface characterization studies demonstrated similar chemistry but significantly greater root-mean-square (rms) surface roughness as measured by atomic force microscopy (AFM) for nanostructured compared with respective conventional metals. For these reasons, results from the present in vitro study provided evidence that vascular stents composed of nanometer compared with micron-sized metal particles (specifically, either cp Ti or CoCrMo) may invoke cellular responses promising for improved vascular stent applications.
    International Journal of Nanomedicine 02/2006; 1(1):41-9. DOI:10.2147/nano.2006.1.1.41 · 4.38 Impact Factor
  • Derick C Miller · Karen M Haberstroh · Thomas J Webster ·
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    ABSTRACT: Studies have shown that poly(lactic-co-glycolic acid) (PLGA) films with nanometer surface features promote vascular endothelial and smooth muscle cell adhesion. The objective of this in vitro research was to begin to understand the mechanisms behind this observed increase in vascular cell adhesion. Results provided evidence that nanostructured PLGA adsorbed significantly more vitronectin and fibronectin from serum compared to conventional (or those not possessing nanometer surface features) PLGA. When separately preadsorbing both vitronectin and fibronectin, increased vascular smooth muscle and endothelial cell density was observed on nanostructured (compared to conventional) PLGA. Additionally, blocking of cell-binding epitopes of fibronectin and vitronectin significantly decreased vascular cell adhesion on nanostructured (compared to conventional) PLGA. For this reason, results of the present in vitro study demonstrated that cell adhesive proteins adsorbed in different quantities and altered bioactivity on nanostructured compared to conventional PLGA topographies, which (at least in part) may account for the documented increased vascular cell adhesion on nanostructured PLGA. In this manner, this study continues to provide evidence for the promise of nanostructured PLGA in vascular tissue engineering applications.
    Journal of Biomedical Materials Research Part A 06/2005; 73(4):476-84. DOI:10.1002/jbm.a.30318 · 3.37 Impact Factor

Publication Stats

2k Citations
157.72 Total Impact Points


  • 2006-2011
    • Brown University
      • School of Engineering
      Providence, Rhode Island, United States
  • 2000-2007
    • Purdue University
      • Weldon School of Biomedical Engineering
      West Lafayette, IN, United States
  • 1999-2002
    • Rensselaer Polytechnic Institute
      • Department of Biomedical Engineering
      New York City, NY, United States