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Closure of Cleanroom Tour Isle next week - July 12-14
by Totten, Mary J 07 Jul '16

07 Jul '16

Everyone, We will be scrubbing and waxing the tour isle around the cleanroom next week. Please note the times you will not be able to access certain areas. Tuesday July 12th - 5:00AM - 9:00AM East side closed (No access to the Bio-CR and J-Bay) Wednesday July 13th - 5:00AM - 9:00AM Both sides closed (No access to Bio-CR, J-Bay, and freight elevator) Thursday July 14th - 5:00AM - 9:00AM West side closed for waxing (No access to the freight elevator) Please let me know if you have any questions, and thank you for your patience. Thank you, Mary Jo Totten Birck Nanotechnology Center Discovery Park/Purdue University 1205 West State Street BRK 1220 West Lafayette, IN 47907-2057 (765) 496-1173 Life is 10% what happens to you and 90% how you react to it. Charles R. Swindoll

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Yee Kan Koh Seminar, July 8th @ 11am in BRK 1001
by Turner, Jaime J 06 Jul '16

06 Jul '16

[cid:image001.png@01D1D78D.F4AFD660] Jaime Turner Administrative Assistant to the Director Birck Nanotechnology Center 1205 West State Street West Lafayette, IN 47907-2057 Email: jjturner(a)purdue.edu<mailto:jjturner@purdue.edu> Phone: 765-494-3509

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3D3C Newsletter - June 2016
by Kwok, Tim 06 Jul '16

06 Jul '16

Dear All, Below please find the fourth issue of the newsletter of the 3D Cell Culture Core (3D3C) Facility of the Birck Nanotechnology Center. The newsletter is also available online (https://nanohub.org/groups/3d3cfacility/news) The four sections in the newsletter are: 3D at Purdue – this section highlights 3D cell culture-based research activity at Purdue 3D in focus – this section presents the current work on a specific 3D cell culture model or technique 3D in publications – this section brings a collection of recent publications on 3D cell culture 3D in meetings – this section includes a list of upcoming meetings related to 3D cell culture The newsletter will be available every two months. If you do not wish to receive the 3D3C newsletter in the future, please reply “cancel” to unsubscribe. Please contact me if you have questions. Yours Sincerely, Tim Kwok Facility Manager 3D Cell Culture Core (3D3C) Facility Birck Nanotechnology Center Purdue University ________________________________ [https://gallery.mailchimp.com/b7d6d1ffee56a866e499104cf/images/3e8e050f-67f…] Volume 4, June 2016 [https://gallery.mailchimp.com/b7d6d1ffee56a866e499104cf/images/10f15e72-d4d…] 3D at Purdue 3D in Focus 3D in Publications 3D in Meetings 3D at Purdue Standardized, Self-assembling Type I Collagens for Modernized In-vitro 3D Human Tumor-Stroma Models — Shooting for the Moon By: Catherine F. Whittington, PHD LIFA Postdoctoral Fellow The Harbin Laboratory has a rich history in the study of interactions between the cell and its surrounding 3D extracellular matrix (ECM). Early on, the laboratory recognized that traditional 2D in- vitro models for many events of development and disease were not amenable to systematic modulation or mechanistic study of specific cell-ECM interactions. Therefore, we developed an uncommon set of type I collagen building blocks (oligomers)1, 3 which retain their inherent fibril-forming capacity and can be used to predictably and reproducibly control fibril- and matrix-level properties of polymerizable matrices to recapitulate what is found in the body’s tissues.6, 10 We have shown that these 3D collagen matrices have biochemical and biophysical bioinstructive function and can be tuned to predictably guide lineage-specific differentiation of mesenchymal stem cells into bone for next generation tissue engineered products or direct vessel network formation by human endothelial colony forming cells (hECFC) for therapeutic vascularization strategies (Figure 1).2, 4, 7, 8, 11 We also use our type I collagen oligomer formulations as a tool for more basic biological research to actively study cell-ECM interactions that are important for drug discovery, toxicity testing, and a myriad of biological activities including disease development and progression.5, 9 A current collaboration with Eli Lilly and Company in Indianapolis, sponsored by the Lilly Innovation Fellowship Award Program, allows us to adapt our collagen technology within a pharmaceutic industry context as a platform to improve upon preclinical tumor models that typically lack the ability to reliably reproduce complex biological signaling inherent to the tumor microenvironment in vivo. Our work seeks to tackle Eli Lilly’s grand challenge of “establishing clinical efficacy and safety earlier in the drug development process” by addressing the limitations of current tumor models (e.g., 2D cell culture and spheroids) through the incorporation of 3D ECMs into existing target validation and drug sensitivity testing methods. At the same time, we are also working to improve how we evaluate efficacy in 3D by adapting existing analysis techniques and high throughput systems to accommodate 3D cultures. Collectively, this effort is working to translate new tools and a better understanding of the role of the tumor microenvironment in cancer initiation, progression, metastasis, and therapeutic responsiveness, a goal consistent with the National Cancer MoonShot Initiative. [https://gallery.mailchimp.com/b7d6d1ffee56a866e499104cf/images/1560510d-9f5…] Figure 1: Schematic representation of a 3D in-vitro vasculogenesis model in which hECFC were suspended within type I collagen to form a vascularized tissue construct. Oligomer collagen matrices supported vascular networks (Green) with lumen that were further stabilized via basement membrane deposition (Red; Bottom image). (Whittington, C.F., Yoder, M.C., Voytik-Harbin, S.L. Macromolecular Bioscience, 13:1135-1149, 2013. ) Recent work from the laboratory focused on multiple cancer types, including colorectal, pancreatic, breast5, and brain9 cancers, used 3D collagen-based ECMs to study how ECM composition and biophysical properties modulate the epithelial to mesenchymal transition (EMT) of cancer cells, which plays a significant role in tumor metastasis and drug resistance. In our study, we used our type I collagen oligomers to study the mechanisms of EMT mechanobiology and found that ECM composition and biophysical properties (stiffness) are important for guiding EMT (Figure 2). Cells not only behaved differently in terms of their EMT status when exposed to a basement membrane (BM; sheet-like; Matrigel) ECM compared to an interstitial (IM; fibrillar; type I collagen) ECM, but they also exhibited varied drug sensitivity. These results provide new insight into how IM fibril microstructure and mechanical properties guide EMT. They also challenge existing correlations between stromal properties and EMT established using conventional preclinical models, and help identify critical parameters for engineering pathophysiologically relevant tumor-stroma models. As we continue to use 3D ECMs in our studies, we gain more insight into how they may contribute to the development of new therapeutic strategies. With each new application we pursue, discoveries are made that reinforce the importance of the 3D ECM in regulating cell behavior in development and disease. As such, we advocate for researchers to consider the ECM as a key component necessary to produce more physiologically relevant models that can help us accelerate the transition of laboratory innovations from bench to bedside. [https://gallery.mailchimp.com/b7d6d1ffee56a866e499104cf/images/af3f7243-cd4…] Figure 2: (A) Schematic representation of EMT progression as epithelial cells (rounded, grouped) break free of the basement membrane (BM) and become more mesenchymal (spindle-shaped) to invade the interstitial matrix (IM). (B) HT29 colorectal cancer cells (Green=F-actin; Blue=nucleus) undergo morphological changes associated with EMT when exposed to decreasing ratios of Matrigel (representing BM) to type I collagen oligomer (representing IM; White=collagen fibrils). Scale bar = 50 µm. Project Contributors: LIFA Postdoctoral Fellow: Catherine F. Whittington PHD Purdue Faculty Mentor: Sherry L. Harbin, PHD Eli Lilly Oncology Group Mentors: Shripad Bhagwat, PHD and Sheng-Bin Peng, PHD Purdue Biomedical Engineering Graduate Student: T.J. Puls Purdue Biomedical Engineering Undergraduate Student: Xiaohong Tan Selected Relevant Publications: 1. Kreger S.T., Bell, B.J., Bailey, J., Stites, E., Kuske, J., Waisner, B., and Voytik-Harbin, S.L. Polymerization and matrix physical properties as important design considerations for soluble collagen formulations. Biopolymers, 93:690-707, 2010. 2. Critser, P.J., Kreger, S.T., Voytik-Harbin, S.L., and Yoder, M.C. Collagen matrix physical properties modulate endothelial colony forming cell derived vessels in vivo. Microvasc Res 80:23-30, 2010. 3. Bailey, J.L., Critser, P.J., Whittington, C., Kuske, J.L., Yoder, M.C., and Voytik-Harbin, S.L. Collagen oligomers modulate physical and biological properties of three-dimensional self-assembled matrices. Biopolymers 95:77-93, 2011. 4. Critser, P.J., Voytik-Harbin, S.L., and Yoder, M.C. Isolating and defining cells to engineer human blood vessels. Cell Prolif 44:15-21, 2011. 5. Monteleon, C.L., Hartsell, A., Sedgwick, A., Whittington, C., Voytik-Harbin, S., and D’Souza- Schorey, C. Inverted Epithelial Cysts: Interlinked roles for ARF6, Rac1 and the matrix microenvironment. Mol Biol Cell 23:4495-505, 2012 6. Whittington, C., Brandner, E., Teo, K.Y., Han, B., Nauman, E., and Voytik-Harbin, S.L. Oligomers modulate interfibril branching and mass transport properties of collagen matrices. Microsc Microanal 19:1323-1333, 2013. 7. Kim, S.J., Wan, Q., Cho, E., Han, B., Yoder, M.C., Voytik-Harbin, S.L., and Na., S. Matrix rigidity regulates spatiotemporal dynamics of Cdc42 activity and vacuole formation kinetics of endothelial colony forming cells. Biochem Biophys Res Commun 443:1280-1285, 2014. 8. Richardson, M.R., Robbins, E.P., Vemula, S., Critser, P.J., Whittington, C., Voytik-Harbin, S.L., and Yoder, M.C. Angiopoietin-like protein 2 regulates endothelial colony forming cell vasculogenesis. Angiogenesis 17:675-683, 2014. 9. Herrera-Perez M, Voytik-Harbin SL, Rickus JL. Extracellular matrix properties regulate the migratory response of glioblastoma stem cells in three-dimensional culture. Tissue Eng Part A 21:2572-82, 2015. 10. Blum, K.M., Novak, T., Watkins, L., Neu, C.P., Wallace, J.M., Bart, Z.R. and Voytik-Harbin, S.L. Acellular and cellular high-density, collagen-fibril constructs with suprafibrillar organization. Biomater Sci 4:711-723, 2016. 11. Buno, K.P., Chen, X., Weibel, J.A., Thiede, S.N., Garimella, S.V., Yoder, M.C., and Voytik- Harbin, S.L. In Vitro Multitissue Interface model supports rapid vasculogenesis and mechanistic study of vascularization across tissue compartments. ACS Appl Mater Interfaces 2016 (Epub ahead of print). ________________________________ 3D in Focus Within the body, cells reside in tissues with distinct physiological microenvironments or niches. Increasing evidence illustrates that the adherent cells cultured as a two-dimensional (2D) monolayer on a plastic surface lack the type of interactions with the microenvironment that normally occur in vivo. The cells cultured under three-dimensional (3D) conditions are enticed to assemble into structures with aspects of the physiologically relevant organization and function of specific tissues. In fact, the more specialized the niche created thanks to appropriate 3D culture conditions, the more exquisite the regulation of cell behavior including cell proliferation, migration, differentiation, survival, etc. For further information on this topic please refer to our discussion below of the article by Marinkovic et al. Marinkovic M, Block TJ, Rakian R, Li Q, Wang E, Reilly MA, Dean DD, Chen XD “One size does not fit all: developing a cell-specific niche for in vitro study of cell behavior” Matrix Biol. (2016) 54–55, 426–441 To address the importance of creating a tissue specific niche in 3D cell culture, the authors prepared an extracellular matrix (ECM) by ‘decellularization’ of microenvironments containing either a matrix synthesized by bone marrow cells (BM-ECM) or a matrix synthesized by adipocytes (AD-ECM). Compared to polystyrene surfaces used for 2D cell culture, the proliferation of mesenchymal stem cells (MSCs) obtained either from the bone marrow or from the adipose tissue was significantly increased (by 1.4 to 2 fold) when cultured in the presence of ECM. The resulting effects depended on the ECM niche (i.e., BM-ECM promoted the proliferation of BM-MSCs over AD-MSCs, and vice versa). Moreover, BM- and AD-ECM preferentially directed the differentiation of both groups of MSCs towards osteogenic lineage and adipogenic lineage, respectively, suggesting a tissue-specific effect of the ECM on MSCs differentiation. To dissect the characteristics of the tissue specific niches, the chemical (protein composition) and physical (topographical and mechanical) properties of the two ECMs were compared. By mass spectrometry, BM- and AD-ECM were found to share approximately 64% of their protein components, mostly collagen type VI, followed by types XII and I. The compositional variation was the greatest with proteoglycans and glycoproteins. Both BM- and AD-ECMs exhibited unique topographical and mechanical properties known to regulate stem cell differentiation. A combination of atomic force microscopy, second-harmonic generation microscopy and immunofluorescence microscopy revealed that BM- and AD-ECMs exhibited unique architectures, largely attributable to variations in collagen VI organization. In immunofluorescence microscopy, collagen VI in BM-ECM was characterized by fine, highly aligned fibrils, while AD-ECM contained fibrils that were less ordered and were organized into denser bundles. Moreover, mechanical characterization with small angle oscillatory shear rheology indicated that BM-ECM was three orders of magnitude stiffer than AD-ECM. According to the authors, the unique topographical and mechanical properties of BM- and AD-ECM may be associated with the preferential effect of each ECM on the differentiation of MSCs. In summary, these experiments conducted with native ECMs (BM-ECM and AD-ECM) that represent the tissue-specific microenvironment (niche) for bone marrow and adipose tissues, outline the importance of developing more sophisticated 3D culture systems in order to replicate the in vivo niches. Such a cell culture goal will require understanding the exact role of individual chemical and physical properties (and/or the combination of these properties) of the ECMs in cell differentiation. ________________________________ 3D in Publications Recent publications on 3D culture (please click to access the list on our web page https://nanohub.org/groups/3d3cfacility) Review<https://nanohub.org/groups/3d3cfacility/news#reviews> The research articles and reviews are arranged in the following categories: Scaffold free/Scaffold Organ/Tissue/Cell Others Spheroids<https://nanohub.org/groups/3d3cfacility/news#spheroids> Organoid<https://nanohub.org/groups/3d3cfacility/news#organoid> Scaffold<https://nanohub.org/groups/3d3cfacility/news#scaffold> Hydrogel<https://nanohub.org/groups/3d3cfacility/news#hydrogel> Matrix<https://nanohub.org/groups/3d3cfacility/news#matrix> Microfluidics<https://nanohub.org/groups/3d3cfacility/news#microfluidic> Microfabrication<https://nanohub.org/groups/3d3cfacility/news#microfabrication> Adipocyte<https://nanohub.org/groups/3d3cfacility/news#adipocyte> Bone<https://nanohub.org/groups/3d3cfacility/news#bone> Bone Marrow<https://nanohub.org/groups/3d3cfacility/news#bonemarrow> Breast<https://nanohub.org/groups/3d3cfacility/news#breast> Colon<https://nanohub.org/groups/3d3cfacility/news#colon> Heart<https://nanohub.org/groups/3d3cfacility/news#heart> Liver<https://nanohub.org/groups/3d3cfacility/news#liver> Lung<https://nanohub.org/groups/3d3cfacility/news#lung> Muscle<https://nanohub.org/groups/3d3cfacility/news#muscle> Nerve<https://nanohub.org/groups/3d3cfacility/news#nerve> Prostate<https://nanohub.org/groups/3d3cfacility/news#prostate> Endothelial cells<https://nanohub.org/groups/3d3cfacility/news#endothelialcells> Fibroblast<https://nanohub.org/groups/3d3cfacility/news#fibroblast> Stem Cells<https://nanohub.org/groups/3d3cfacility/news#stemcells> Stromal Cells<https://nanohub.org/groups/3d3cfacility/news#stromalcells> Cancer/Tumor<https://nanohub.org/groups/3d3cfacility/news#cancer> Screening<https://nanohub.org/groups/3d3cfacility/news#screening> 3D bioprinting<https://nanohub.org/groups/3d3cfacility/news#3dbioprinting> Imaging<https://nanohub.org/groups/3d3cfacility/news#imaging> ________________________________ 3D in Meetings Bioprinting & 3D Printing in the Life Sciences Date: 21st to 22nd July 2016 Location: Singapore Website:http://selectbiosciences.com/conferences/index.aspx?conf=BIO3D Contact person: Paul Raggett 3D Tissue Models 2016 Date: 29th to 31st August 2016 Location: San Diego, CA, USA Website: https://go.evvnt.com/60400-0 Contact person: Aarti Diwan 3D Tissue Models 2016 is designed to tackle critical questions about the true utility and limitations of 3D tissue models in pharmaceutical development. Organized by: Hanson Wade 2nd EACR Conference on Goodbye Flat Biology: Models, Mechanisms and Microenvironment Date: 2nd to 5th October 2016 Location: Berlin, Germany Website: http://www.eacr.org/goodbyeflatbiology2016/index.php Contact person: Roger Doxat-Pratt The meeting should be of interest to all those who use cancer cell lines, patient-derived tissue samples or primary cultures in vitro for the study of tumour biology, bioengineering and biochemistry, drug target validation, etc. Organized by: European Association for Cancer Research Deadline for abstracts/proposals: 20th June 2016 14th Annual High-Content Analysis & 3D Screening Date: 31st October to 2nd November 2016 Location: Cambridge, MA, USA Website: http://www.highcontentanalysis.com/ Contact person: Jaime Hodges Event will deliver the latest advancements in HCA applications and technologies, and the next steps for physiologically relevant complex models, ultra-high resolution and high-throughput imaging, and more advanced image analysis and data management. Organized by: Cambridge Healthtech Institute SPIE BiOS 2017 - Part of SPIE Photonics West 2017 Date: 28th January to 2nd February 2017 Location: San Francisco, CA, USA Website: http://spie.org/SPIE-BiOS-conference Contact person: Customer Service BiOS 2017, part of SPIE Photonics West 2017, is the world’s largest biomedical optics and biophotonics conference. Topics range from biomedical optics, photonic diagnostic and therapeutic tools and systems, nano/biophotonics, and more! Organized by: SPIE - The international society for optics and photonics Deadline for abstracts/proposals: 18th July 2016

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Reminder: NEEDS Seminar: James Teherani (Columbia) BRK 1001; Thursday, June 30, 10:30
by Johnson, Vicki L. 30 Jun '16

30 Jun '16

Auger generation as an intrinsic limit to tunneling field-effect transistor performance James Teherani Department of Electrical Engineering, Columbia University Birck 1001: Thursday, June 30 from 10:30-11:30 AM Abstract: Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society’s best hope for achieving a > 10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance.

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Mailroom label maker
by Totten, Mary J 28 Jun '16

28 Jun '16

If you have borrowed the label maker from the mailroom, could you please return it ASAP. There are other users that need to use it :) Thank you, Mary Jo Totten Birck Nanotechnology Center Discovery Park/Purdue University 1205 West State Street BRK 1220 West Lafayette, IN 47907-2057 (765) 496-1173 Life is 10% what happens to you and 90% how you react to it. Charles R. Swindoll

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NEEDS Seminar: James Teherani (Columbia) BRK 1001; Thursday, June 30, 10:30
by Johnson, Vicki L. 28 Jun '16

28 Jun '16

Auger generation as an intrinsic limit to tunneling field-effect transistor performance James Teherani Department of Electrical Engineering, Columbia University Birck 1001: Thursday, June 30 from 10:30-11:30 AM Abstract: Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society’s best hope for achieving a > 10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance.

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Pink Walrus Frozen Yogurt
by Anthrop, Heather L 28 Jun '16

28 Jun '16

[cid:image003.jpg@01D1D127.01FF3FD0]

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Birck Nanotechnology Center Hydrogen Supply
by Reger, Ronald K 27 Jun '16

27 Jun '16

Dear all Birck equipment users, This morning we discovered that the hydrogen generator in the Birck subfab has a defective/broken cooling fan and is therefore inoperable. A new fan is being ordered but until it arrives and can be installed we are on the back-up hydrogen supply from the tanks located out back near the LN2 system. No interruption of hydrogen should be seen, but if you have a particularly long process run that requires medium to high flow rates please get with Kenny Schwartz prior to your run so he can make sure we have ample supply for your process. We hope to have the fan repaired and the generator back online within 1 - 2 weeks. Thanks for your support. Birck Engineering

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BNC E-news for the week of June 27th
by Anthrop, Heather L 27 Jun '16

27 Jun '16

. We Welcome a New Staff Engineer! The Birck engineering staff welcomes Joon Park who is joining our team as a full-time staff member on Monday June 27th. Joon has a BS and MS in Mechanical Engineering, and he is completing his PhD at Purdue in ABE. Joon brings a wealth of knowledge and experience gained in his studies and in work assignments supporting major Korean auto manufacturers. Joon’s responsibilities will include a variety of instruments and control systems, and also processing services. We look forward to having Joon as a member of our team! Monday, June 27, 2016 @ 11:00am BRK, ROOM 1001 Subhasis Ghosh School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067 Email: subhasis.ghosh.jnu(a)gmail.com<mailto:subhasis.ghosh.jnu@gmail.com>, subhasis(a)mail.jnu.ac.in<mailto:subhasis@mail.jnu.ac.in> Title: Many Body Effects on Optical Properties of Graphene Abstract: Graphene, a two-dimensional (2D) material shows remarkable optical and electronic properties, such as a linear energy dispersion, chirality and half-integer quantum Hall effect. Multilayer graphene flakes, held together by weak van der Waals forces have also attracted attention due to their stacking dependent electronic and optical properties. Interestingly, a vast majority of these properties can be understood in terms of a non-interacting picture. In particular, the optical conductivity of monolayer graphene in the near infra-red and visible range has been found to be independent of frequency, and equal to e2/4ђ. From experimental investigations of the optical properties of chemically exfoliated mono and multilayered graphene flakes, we probe the effect of electron-electron interactions on the universal optical transmittance and excitons in graphene. The electron-electron or Coulomb interaction strength is varied both by modulating the dielectric constant of the exfoliating solvent, as well as changes in the carrier density. To vary the carrier density controllably, a method has been developed to dope (n-type and p-type) graphene monolayers through charge transfer interaction by trapping selected organic molecules between graphene and underneath substrates. Controllability has been demonstrated in terms of shift in Raman spectra and Dirac point in graphene monolayers. We find that the universality is robust throughout the visible range of the spectrum, and this is consistent with chiral symmetry as its origin. It has been shown that universality is broken if chiral symmetry can be broken. This is further supported by changes in the excitonic features which could disrupt the chiral symmetry. The shift and broadening of excitonic features are found to impact the onset of universality at low wavelengths. Our experiments also help to verify the theoretically predicted transmittance spectra in the presence of Coulomb interactions and resolve the discrepancy in the numerical factor governing the magnitude and frequency dependence of the transmittance in monolayer. [cid:image003.jpg@01D1D04E.20665960]

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REMINDER: NEEDS Seminar: Enrico Bellotti - Monday, June 27 from 3-4PM, BRK 2001
by Johnson, Vicki L. 27 Jun '16

27 Jun '16

Numerical Modeling of III-Nitride Semiconductors: >From Material Properties to Device Performance Enrico Bellotti Boston University Birck 2001: Monday, June 27 from 3:00-4:00PM Abstract: This talk presents the current research activities of the BU Computational Electronics Group, which are aimed at developing multi-scale modeling approaches for semiconductor materials and devices. The first part of this talk will discuss the application of this methodology in examining the breakdown properties of wide band gap semiconductors, in particular GaN and AlGaN. Starting from DFT-based electronic structure calculations and computing the carrier phonon interaction without including fitting parameters, it will be shown that it is possible to predict macroscopic device performance of avalanche photodetectors and power rectifiers. The second part of this talk will discuss the current research aimed at understanding the behavior of dislocations, defect formation and migration in GaN, their impact on the electronic and optical material properties, and ultimately device reliability. The work at Boston Univ. has been supported in part by the U.S. Army Research Laboratory through the Collaborative Research Alliance (CRA) for MultiScale multidisciplinary Modeling of Electronic materials (MSME), NSF, ARO, CERDEC-NVESD and DRS.

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