1
|
Nagaratnam N, Martin-Garcia JM, Yang JH, Goode MR, Ketawala G, Craciunescu FM, Zook JD, Sonowal M, Williams D, Grant TD, Fromme R, Hansen DT, Fromme P. Structural and biophysical properties of FopA, a major outer membrane protein of Francisella tularensis. PLoS One 2022; 17:e0267370. [PMID: 35913965 PMCID: PMC9342783 DOI: 10.1371/journal.pone.0267370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is an extremely infectious pathogen and a category A bioterrorism agent. It causes the highly contagious zoonosis, Tularemia. Currently, FDA approved vaccines against tularemia are unavailable. F. tularensis outer membrane protein A (FopA) is a well-studied virulence determinant and protective antigen against tularemia. It is a major outer membrane protein (Omp) of F. tularensis. However, FopA-based therapeutic intervention is hindered due to lack of complete structural information for membrane localized mature FopA. In our study, we established recombinant expression, monodisperse purification, crystallization and X-ray diffraction (~6.5 Å) of membrane localized mature FopA. Further, we performed bioinformatics and biophysical experiments to unveil its structural organization in the outer membrane. FopA consists of 393 amino acids and has less than 40% sequence identity to known bacterial Omps. Using comprehensive sequence alignments and structure predictions together with existing partial structural information, we propose a two-domain organization for FopA. Circular dichroism spectroscopy and heat modifiability assay confirmed FopA has a β-barrel domain consistent with alphafold2’s prediction of an eight stranded β-barrel at the N-terminus. Small angle X-ray scattering (SAXS) and native-polyacrylamide gel electrophoresis revealed FopA purified in detergent micelles is predominantly dimeric. Molecular density derived from SAXS at 31 Å shows putative dimeric N-terminal β-barrels surrounded by detergent corona and connected to C-terminal domains via flexible linker. Disorder analysis predicts N- and C-terminal domains are interspersed by a long intrinsically disordered region and alphafold2 predicts this region to be largely unstructured. Taken together, we propose a dimeric, two-domain organization of FopA in the outer membrane: the N-terminal β-barrel is membrane embedded, provides dimerization interface and tethers to membrane extrinsic C-terminal domain via long flexible linker. Structure determination of membrane localized mature FopA is essential to understand its role in pathogenesis and develop anti-tularemia therapeutics. Our results pave the way towards it.
Collapse
Affiliation(s)
- Nirupa Nagaratnam
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jose M. Martin-Garcia
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jay-How Yang
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Matthew R. Goode
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Gihan Ketawala
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Felicia M. Craciunescu
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - James D. Zook
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Manashi Sonowal
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Dewight Williams
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Eyring Materials Center, Arizona State University, Tempe, Arizona, United States of America
| | - Thomas D. Grant
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, New York, New York, United States of America
| | - Raimund Fromme
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Debra T. Hansen
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Center for Innovations in Medicine, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Petra Fromme
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
| |
Collapse
|
2
|
Dela Cruz Chuh J, Go M, Chen Y, Guo J, Rafidi H, Mandikian D, Sun Y, Lin Z, Schneider K, Zhang P, Vij R, Sharpnack D, Chan P, de la Cruz C, Sadowsky J, Seshasayee D, Koerber JT, Pillow TH, Phillips GD, Rowntree RK, Boswell CA, Kozak KR, Polson AG, Polakis P, Yu SF, Dragovich PS, Agard NJ. Preclinical optimization of Ly6E-targeted ADCs for increased durability and efficacy of anti-tumor response. MAbs 2021; 13:1862452. [PMID: 33382956 PMCID: PMC7784788 DOI: 10.1080/19420862.2020.1862452] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/23/2020] [Accepted: 12/07/2020] [Indexed: 11/13/2022] Open
Abstract
Early success with brentuximab vedotin in treating classical Hodgkin lymphoma spurred an influx of at least 20 monomethyl auristatin E (MMAE) antibody-drug conjugates (ADCs) into clinical trials. While three MMAE-ADCs have been approved, most of these conjugates are no longer being investigated in clinical trials. Some auristatin conjugates show limited or no efficacy at tolerated doses, but even for drugs driving initial remissions, tumor regrowth and metastasis often rapidly occur. Here we describe the development of second-generation therapeutic ADCs targeting Lymphocyte antigen 6E (Ly6E) where the tubulin polymerization inhibitor MMAE (Compound 1) is replaced with DNA-damaging agents intended to drive increased durability of response. Comparison of a seco-cyclopropyl benzoindol-4-one (CBI)-dimer (compound 2) to MMAE showed increased potency, activity across more cell lines, and resistance to efflux by P-glycoprotein, a drug transporter commonly upregulated in tumors. Both anti-Ly6E-CBI and -MMAE conjugates drove single-dose efficacy in xenograft and patient-derived xenograft models, but seco-CBI-dimer conjugates showed reduced tumor outgrowth following multiple weeks of treatment, suggesting that they are less susceptible to developing resistance. In parallel, we explored approaches to optimize the targeting antibody. In contrast to immunization with recombinant Ly6E or Ly6E DNA, immunization with virus-like particles generated a high-affinity anti-Ly6E antibody. Conjugates to this antibody improve efficacy versus a previous clinical candidate both in vitro and in vivo with multiple cytotoxics. Conjugation of compound 2 to the second-generation antibody results in a substantially improved ADC with promising preclinical efficacy.
Collapse
Affiliation(s)
- Josefa Dela Cruz Chuh
- Departments of Biochemical and Cellular Pharmacology, Genentech Inc, South San Francisco, CA, USA
| | - MaryAnn Go
- Research biology, Genentech Inc, South San Francisco, CA, USA
| | - Yvonne Chen
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Jun Guo
- Research biology, Genentech Inc, South San Francisco, CA, USA
| | - Hanine Rafidi
- Preclinical & Translational Pharmacokinetics and Pharmacodynamics, Genentech Inc, South San Francisco, CA, USA
| | - Danielle Mandikian
- Preclinical & Translational Pharmacokinetics and Pharmacodynamics, Genentech Inc, South San Francisco, CA, USA
| | - Yonglian Sun
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Zhonghua Lin
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Kellen Schneider
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Pamela Zhang
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Rajesh Vij
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Danielle Sharpnack
- Departments of Biochemical and Cellular Pharmacology, Genentech Inc, South San Francisco, CA, USA
| | - Pamela Chan
- Departments of Biochemical and Cellular Pharmacology, Genentech Inc, South San Francisco, CA, USA
| | | | - Jack Sadowsky
- Protein Chemistry, Genentech Inc, South San Francisco, CA, USA
| | - Dhaya Seshasayee
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - James T. Koerber
- Antibody Engineering, Genentech Inc, South San Francisco, CA, USA
| | - Thomas H. Pillow
- Discovery Chemistry, Genentech Inc, South San Francisco, CA, USA
| | | | | | - C. Andrew Boswell
- Preclinical & Translational Pharmacokinetics and Pharmacodynamics, Genentech Inc, South San Francisco, CA, USA
| | - Katherine R. Kozak
- Departments of Biochemical and Cellular Pharmacology, Genentech Inc, South San Francisco, CA, USA
| | | | - Paul Polakis
- Research biology, Genentech Inc, South San Francisco, CA, USA
| | - Shang-Fan Yu
- Research biology, Genentech Inc, South San Francisco, CA, USA
| | | | | |
Collapse
|
3
|
Membrane directed expression in Escherichia coli of BBA57 and other virulence factors from the Lyme disease agent Borrelia burgdorferi. Sci Rep 2019; 9:17606. [PMID: 31772280 PMCID: PMC6879480 DOI: 10.1038/s41598-019-53830-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022] Open
Abstract
Membrane-embedded proteins are critical to the establishment, survival and persistence in the host of the Lyme disease bacterium Borrelia burgdorferi (Bb), but to date, there are no solved structures of transmembrane proteins representing these attractive therapeutic targets. All available structures from the genus Borrelia represent proteins expressed without a membrane-targeting signal peptide, thus avoiding conserved pathways that modify, fold and assemble membrane protein complexes. Towards elucidating structure and function of these critical proteins, we directed translocation of eleven expression-optimized Bb virulence factors, including the signal sequence, to the Escherichia coli membrane, of which five, BBA57, HtrA, BB0238, BB0323, and DipA, were expressed with C-terminal His-tags. P66 was also expressed using the PelB signal sequence fused to maltose binding protein. Membrane-associated BBA57 lipoprotein was solubilized by non-ionic and zwitterionic detergents. We show BBA57 translocation to the outer membrane, purification at a level sufficient for structural studies, and evidence for an α-helical multimer. Previous studies showed multiple critical roles of BBA57 in transmission, joint arthritis, carditis, weakening immune responses, and regulating other Bb outer surface proteins. In describing the first purification of membrane-translocated BBA57, this work will support subsequent studies that reveal the precise mechanisms of this important Lyme disease virulence factor.
Collapse
|
4
|
Shen L, Zhang J, Lee H, Batista MT, Johnston SA. RNA Transcription and Splicing Errors as a Source of Cancer Frameshift Neoantigens for Vaccines. Sci Rep 2019; 9:14184. [PMID: 31578439 PMCID: PMC6775166 DOI: 10.1038/s41598-019-50738-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/13/2019] [Indexed: 12/30/2022] Open
Abstract
The success of checkpoint inhibitors in cancer therapy is largely attributed to activating the patient's immune response to their tumor's neoantigens arising from DNA mutations. This realization has motivated the interest in personal cancer vaccines based on sequencing the patient's tumor DNA to discover neoantigens. Here we propose an additional, unrecognized source of tumor neoantigens. We show that errors in transcription of microsatellites (MS) and mis-splicing of exons create highly immunogenic frameshift (FS) neoantigens in tumors. The sequence of these FS neoantigens are predictable, allowing creation of a peptide array representing all possible neoantigen FS peptides. This array can be used to detect the antibody response in a patient to the FS peptides. A survey of 5 types of cancers reveals peptides that are personally reactive for each patient. This source of neoantigens and the method to discover them may be useful in developing cancer vaccines.
Collapse
Affiliation(s)
- Luhui Shen
- The Biodesign Institute Center for Innovations in Medicine, Arizona State University, Tempe, AZ, USA
| | - Jian Zhang
- The Biodesign Institute Center for Innovations in Medicine, Arizona State University, Tempe, AZ, USA
| | - HoJoon Lee
- The Biodesign Institute Center for Innovations in Medicine, Arizona State University, Tempe, AZ, USA.,Stanford University, Stanford, CA, USA
| | - Milene Tavares Batista
- The Biodesign Institute Center for Innovations in Medicine, Arizona State University, Tempe, AZ, USA
| | - Stephen Albert Johnston
- The Biodesign Institute Center for Innovations in Medicine, Arizona State University, Tempe, AZ, USA.
| |
Collapse
|
5
|
Analysis of the effect of promoter type and skin pretreatment on antigen expression and antibody response after gene gun-based immunization. PLoS One 2018; 13:e0197962. [PMID: 29856790 PMCID: PMC5983433 DOI: 10.1371/journal.pone.0197962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/13/2018] [Indexed: 11/29/2022] Open
Abstract
Monoclonal antibodies (mAbs) have enabled numerous basic research discoveries and therapeutic approaches for many protein classes. However, there still exist a number of target classes, such as multi-pass membrane proteins, for which antibody discovery is difficult, due in part to lack of high quality, recombinant protein. Here we describe the impact of several parameters on antigen expression and the development of mAbs against human claudin 4 (CLDN4), a potential multi-indication cancer target. Using gene gun-based DNA delivery and bioluminescence imaging, we optimize promoter type by comparing expression profiles of four robust in vivo promoters. In addition, we observe that most vectors rapidly lose expression, ultimately reaching almost background levels by three days post-delivery. Recognizing this limitation, we next explored skin pretreatment strategies as an orthogonal method to further boost the efficiency of mAb generation. We show that SDS pretreatment can boost antigen expression, but fails to significantly increase mAb discovery efficiency. In contrast, we find that sandpaper pretreatment yields 5-fold more FACS+ anti-CLDN4 hybridomas, without impacting antigen expression. Our findings coupled with other strategies to improve DNA immunizations should improve the success of mAb discovery against other challenging targets and enable the generation of critical research tools and therapeutic candidates.
Collapse
|
6
|
Immunization of Pigs by DNA Prime and Recombinant Vaccinia Virus Boost To Identify and Rank African Swine Fever Virus Immunogenic and Protective Proteins. J Virol 2018; 92:JVI.02219-17. [PMID: 29386289 PMCID: PMC5874426 DOI: 10.1128/jvi.02219-17] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/14/2018] [Indexed: 12/20/2022] Open
Abstract
African swine fever virus (ASFV) causes an acute hemorrhagic fever in domestic pigs, with high socioeconomic impact. No vaccine is available, limiting options for control. Although live attenuated ASFV can induce up to 100% protection against lethal challenge, little is known of the antigens which induce this protective response. To identify additional ASFV immunogenic and potentially protective antigens, we cloned 47 viral genes in individual plasmids for gene vaccination and in recombinant vaccinia viruses. These antigens were selected to include proteins with different functions and timing of expression. Pools of up to 22 antigens were delivered by DNA prime and recombinant vaccinia virus boost to groups of pigs. Responses of immune lymphocytes from pigs to individual recombinant proteins and to ASFV were measured by interferon gamma enzyme-linked immunosorbent spot (ELISpot) assays to identify a subset of the antigens that consistently induced the highest responses. All 47 antigens were then delivered to pigs by DNA prime and recombinant vaccinia virus boost, and pigs were challenged with a lethal dose of ASFV isolate Georgia 2007/1. Although pigs developed clinical and pathological signs consistent with acute ASFV, viral genome levels were significantly reduced in blood and several lymph tissues in those pigs immunized with vectors expressing ASFV antigens compared with the levels in control pigs.IMPORTANCE The lack of a vaccine limits the options to control African swine fever. Advances have been made in the development of genetically modified live attenuated ASFV that can induce protection against challenge. However, there may be safety issues relating to the use of these in the field. There is little information about ASFV antigens that can induce a protective immune response against challenge. We carried out a large screen of 30% of ASFV antigens by delivering individual genes in different pools to pigs by DNA immunization prime and recombinant vaccinia virus boost. The responses in immunized pigs to these individual antigens were compared to identify the most immunogenic. Lethal challenge of pigs immunized with a pool of antigens resulted in reduced levels of virus in blood and lymph tissues compared to those in pigs immunized with control vectors. Novel immunogenic ASFV proteins have been identified for further testing as vaccine candidates.
Collapse
|
7
|
Hansen DT, Craciunescu FM, Fromme P, Johnston SA, Sykes KF. Generation of High-Specificity Antibodies against Membrane Proteins Using DNA-Gold Micronanoplexes for Gene Gun Immunization. ACTA ACUST UNITED AC 2018. [PMID: 29516482 DOI: 10.1002/cpps.50] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Membrane proteins are the molecular interface of the cell and its environs; however, studies of membrane proteins are highly technically challenging, mainly due to instability of the isolated protein. Towards the production of antibodies that recognize properly folded and stabilized forms of membrane protein antigen, we describe a DNA-based immunization method for mice that expresses the antigen in the membranes of dendritic cells, thus allowing direct presentation to the immune system. This genetic immunization approach employs a highly efficient method of biolistic delivery based on DNA-gold micronanoplexes, which are complexes of micron-sized gold particles that allow dermal penetration and nanometer-sized gold particles that provide a higher surface area for DNA binding than micron gold alone. In contrast to antibodies derived from immunizations with detergent-solubilized protein or with protein fragments, antibodies from genetic immunization are expected to have a high capacity for binding conformational epitopes and for modulating membrane protein activity. © 2018 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Debra T Hansen
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona
| | - Felicia M Craciunescu
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona
| | - Petra Fromme
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona
| | - Stephen A Johnston
- Biodesign Center for Innovations in Medicine, Arizona State University, Tempe, Arizona
| | - Kathryn F Sykes
- Biodesign Center for Innovations in Medicine, Arizona State University, Tempe, Arizona.,Current address: HealthTell, Inc, Chandler, Arizona
| |
Collapse
|
8
|
Ching KH, Collarini EJ, Abdiche YN, Bedinger D, Pedersen D, Izquierdo S, Harriman R, Zhu L, Etches RJ, van de Lavoir MC, Harriman WD, Leighton PA. Chickens with humanized immunoglobulin genes generate antibodies with high affinity and broad epitope coverage to conserved targets. MAbs 2017; 10:71-80. [PMID: 29035625 PMCID: PMC5800366 DOI: 10.1080/19420862.2017.1386825] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Transgenic animal platforms for the discovery of human monoclonal antibodies have been developed in mice, rats, rabbits and cows. The immune response to human proteins is limited in these animals by their tolerance to mammalian-conserved epitopes. To expand the range of epitopes that are accessible, we have chosen an animal host that is less phylogenetically related to humans. Specifically, we generated transgenic chickens expressing antibodies from immunoglobulin heavy and light chain loci containing human variable regions and chicken constant regions. From these birds, paired human light and heavy chain variable regions are recovered and cloned as fully human recombinant antibodies. The human antibody-expressing chickens exhibit normal B cell development and raise immune responses to conserved human proteins that are not immunogenic in mice. Fully human monoclonal antibodies can be recovered with sub-nanomolar affinities. Binning data of antibodies to a human protein show epitope coverage similar to wild type chickens, which we previously showed is broader than that produced from rodent immunizations.
Collapse
Affiliation(s)
- Kathryn H Ching
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Ellen J Collarini
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Yasmina N Abdiche
- b Carterra, Inc. , 825 N. 300 W., Suite C309, Salt Lake City , UT , USA
| | - Daniel Bedinger
- b Carterra, Inc. , 825 N. 300 W., Suite C309, Salt Lake City , UT , USA
| | - Darlene Pedersen
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Shelley Izquierdo
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Rian Harriman
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Lei Zhu
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Robert J Etches
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | | | - William D Harriman
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| | - Philip A Leighton
- a Ligand Pharmaceuticals Incorporated , 5980 Horton Street, Suite 405, Emeryville , CA , USA
| |
Collapse
|
9
|
Ansari AS, Santerre PJ, Uludağ H. Biomaterials for polynucleotide delivery to anchorage-independent cells. J Mater Chem B 2017; 5:7238-7261. [DOI: 10.1039/c7tb01833a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Comparison of various chemical vectors used for polynucleotide delivery to mammalian anchorage-independent cells.
Collapse
Affiliation(s)
- Aysha S. Ansari
- Department of Chemical & Materials Engineering
- Faculty of Engineering
- University of Alberta
- Edmonton
- Canada
| | - Paul J. Santerre
- Institute of Biomaterials & Biomedical Engineering
- University of Toronto
- Toronto
- Canada
| | - Hasan Uludağ
- Department of Chemical & Materials Engineering
- Faculty of Engineering
- University of Alberta
- Edmonton
- Canada
| |
Collapse
|