@article{bain_kirste_johnson_ghashghaei_collazo_ivanisevic_2016, title={Neurotypic cell attachment and growth on III-nitride lateral polarity structures}, volume={58}, ISSN={["1873-0191"]}, DOI={10.1016/j.msec.2015.09.084}, abstractNote={III-nitride materials have recently received increasing levels of attention for their potential to successfully interface with, and sense biochemical interactions in biological systems. Expanding on available sensing schemes (including transistor-based devices,) a III-N lateral polarity structure capable of introducing quasi-phase matching through a periodic polarity grating presents a novel platform for second harmonic generation. This platform constitutes a non-linear optical phenomenon with exquisite sensitivity to the chemical state of a surface or interface. To characterize the response of a biological system to the nanostructured lateral polarity structures, we cultured neurotypic PC12 cells on AlGaN with varying ratios of Al:Ga - 0, 0.4, 0.6, and 1 - and on surfaces of varying pitch to the III-polar vs. N-polar grating - 5, 10, 20 and 50 μm. While some toxicity associated with increasing Al is observed, we documented and quantified trends in cell responses to the local material polarity and nanoscale roughness. The nitrogen-polar material has a significantly higher nanoscale roughness than III-polar regions, and a 80-200 nm step height difference between the III-polar and N-polar materials in the lateral polarity configuration generates adequate changes in topography to influence cell growth, improves cell adhesion and promotes cell migration along the direction of the features. As the designed material configuration is further explored for biochemical sensing, the lateral polarity scheme may provide a route in assessing the non-specific protein adsorption to this varying nano-topography that drives the subsequent cell response.}, journal={MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS}, author={Bain, L. E. and Kirste, R. and Johnson, C. A. and Ghashghaei, H. T. and Collazo, R. and Ivanisevic, A.}, year={2016}, month={Jan}, pages={1194–1198} }
 @article{bain_hoffmann_bryan_collazo_ivanisevic_2015, title={Adsorption and adhesion of common serum proteins to nanotextured gallium nitride}, volume={7}, ISSN={["2040-3372"]}, DOI={10.1039/c4nr06353h}, abstractNote={Morphology can be used to modulate the adsorption of proteins onto gallium nitride.}, number={6}, journal={NANOSCALE}, author={Bain, Lauren E. and Hoffmann, Marc P. and Bryan, Isaac and Collazo, Ramon and Ivanisevic, Albena}, year={2015}, pages={2360–2365} }
 @misc{bain_ivanisevic_2015, title={Engineering the Cell-Semiconductor Interface: A Materials Modification Approach using II-VI and III-V Semiconductor Materials}, volume={11}, ISSN={["1613-6829"]}, DOI={10.1002/smll.201401450}, abstractNote={Developing functional biomedical devices based on semiconductor materials requires an understanding of interactions taking place at the material-biosystem interface. Cell behavior is dependent on the local physicochemical environment. While standard routes of material preparation involve chemical functionalization of the active surface, this review emphasizes both biocompatibility of unmodified surfaces as well as use of topographic features in manipulating cell-material interactions. Initially, the review discusses experiments involving unmodified II-VI and III-V semiconductors - a starting point for assessing cytotoxicity and biocompatibility - followed by specific surface modification, including the generation of submicron roughness or the potential effect of quantum dot structures. Finally, the discussion turns to more recent work in coupling topography and specific chemistry, enhancing the tunability of the cell-semiconductor interface. With this broadened materials approach, researchers' ability to tune the interactions between semiconductors and biological environments continues to improve, reaching new heights in device function.}, number={7}, journal={SMALL}, author={Bain, Lauren E. and Ivanisevic, Albena}, year={2015}, month={Feb}, pages={768–780} }
 @article{bain_collazo_hsu_latham_manfra_ivanisevic_2014, title={Surface topography and chemistry shape cellular behavior on wide band-gap semiconductors}, volume={10}, ISSN={1742-7061}, url={http://dx.doi.org/10.1016/J.ACTBIO.2014.02.038}, DOI={10.1016/j.actbio.2014.02.038}, abstractNote={The chemical stability and electrical properties of gallium nitride make it a promising material for the development of biocompatible electronics, a range of devices including biosensors as well as interfaces for probing and controlling cellular growth and signaling. To improve the interface formed between the probe material and the cell or biosystem, surface topography and chemistry can be applied to modify the ways in which the device interacts with its environment. PC12 cells are cultured on as-grown planar, unidirectionally polished, etched nanoporous and nanowire GaN surfaces with and without a physisorbed peptide sequence that promotes cell adhesion. While cells demonstrate preferential adhesion to roughened surfaces over as-grown flat surfaces, the topography of that roughness also influences the morphology of cellular adhesion and differentiation in neurotypic cells. Addition of the peptide sequence generally contributes further to cellular adhesion and promotes development of stereotypic long, thin neurite outgrowths over alternate morphologies. The dependence of cell behavior on both the topographic morphology and surface chemistry is thus demonstrated, providing further evidence for the importance of surface modification for modulating bio-inorganic interfaces.}, number={6}, journal={Acta Biomaterialia}, publisher={Elsevier BV}, author={Bain, Lauren E. and Collazo, Ramon and Hsu, Shu-han and Latham, Nicole Pfiester and Manfra, Michael J. and Ivanisevic, Albena}, year={2014}, month={Jun}, pages={2455–2462} }
 @article{bain_jewett_mukund_bedair_paskova_ivanisevic_2013, title={Biomolecular Gradients via Semiconductor Gradients: Characterization of Amino Acid Adsorption to InxGa1–xN Surfaces}, volume={5}, ISSN={1944-8244 1944-8252}, url={http://dx.doi.org/10.1021/AM4015555}, DOI={10.1021/am4015555}, abstractNote={The band gap of indium gallium nitride can be tuned by varying the compositional ratio of indium to gallium, spanning the entire visible region and extending into the near-infrared and near-ultraviolet. This tunability allows for device optimization specific to different applications, including as a biosensor or platform for studying biological interactions. However, these rely on chemically dependent interactions between the device surface and the biostructures of interest. This study presents a material gradient of changing In:Ga composition and the subsequent evaluation of amino acid adsorption to this surface. Arginine is adsorbed to the surface in conditions both above and below the isoelectric point, providing insight to the role of electrostatic interactions in interface formation. These electrostatics are the driving force of the observed adsorption behaviors, with protonated amino acid demonstrating increased adsorption as a function of native surface oxide buildup. We thus present a gradient inorganic substrate featuring varying affinity for amino acid adhesion, which can be applied in generating gradient architectures for biosensors and studying cellular behaviors without application of specialized patterning processes.}, number={15}, journal={ACS Applied Materials & Interfaces}, publisher={American Chemical Society (ACS)}, author={Bain, Lauren E and Jewett, Scott A and Mukund, Aadhithya Hosalli and Bedair, Salah M and Paskova, Tania M and Ivanisevic, Albena}, year={2013}, month={Jul}, pages={7236–7243} }