PacSurf2014 Session BI-TuP: Biomaterial Interfaces Poster Session

Tuesday, December 9, 2014 4:00 PM in Room Mauka

Time Period TuP Sessions | Topic BI Sessions | Time Periods | Topics | PacSurf2014 Schedule

BI-TuP-1 Three-dimensional Conducting Polymer-based Bioelectronic Interfaces for Rare Cell Isolation and Detection
Yu-Sheng Hsiao (Ming Chi University of Technology, Taiwan, Republic of China); Hsiao-hua Yu (Academia Sinica, Taiwan, Republic of China); Hsian-Rong Tseng (University of California, Los Angeles); Peilin Chen (Academia Sinica, Taiwan, Republic of China)

Here we develop a universal solution-processing approach for producing three dimensional (3D) conducting polymer-based bioelectronic interfaces (BEIs), which can be integrated on chips for rare circulating tumor cell (CTC) isolation and detection. Based on the modified poly(dimethylsiloxane) (PDMS) transfer printing technology and bioconjugation process, the poly(3,4-ethylenedioxythiophene) (PEDOT)-based micro/nanorod array films can be fabricated with topographical and chemical control, respectively. This 3D PEDOT-based BEI film features the advantageous characteristics: (1) diverse dimensional structures (tunable from the microscale to the nanoscale), (2) varied surface chemical properties (tunable from nonspecific to specific), (3) high electrical conductivity, and (4) reversible electrochemical switching, and (5) high optical transparency. Furthermore, we integrated this 3D PEDOT-based BEI onchips, which exhibited optimal cell-capture efficiency from MCF7 cells was approximately 85%; featured highly efficient performance for the cell isolation of rare CTCs with minimal contamination from surrounding nontargeted cells (e.g., EpCAM-negative cells, white blood cells); preserved the cell viability with negligible effect on cells. According to the electric cell-substrate impedance sensing concept, the 3D BEI-based device was also demonstrated as a rapid, sensitive and specific tool for CTC detection. Therefore, it is conceivable that use of this platform will meet the requirements on developing for the next-generation bioelectronics for biomedical applications.

Keywords: Poly(3,4-ethylenedioxythiophene) (PEDOT), bioelectronic interfaces (BEIs), circulating tumor cell (CTC), epithelial cell adhesion molecule (EpCAM).

BI-TuP-2 Adsorption Kinetics of Human Tear Proteins on Hydrogel Surfaces
Hyeran Noh (Seoul National University of Science and Technology, Republic of Korea)
Protein adsorption kinetics was studied with the amount of proteins adsorbed to contact lens hydrogels over time scales. HEMA (hydroxyethylmathacrylate) and silicone hydrogels were dipped in protein solutions (albumin or IgG) and adsorption amounts were measured over time scales. The amount of protein adsorbed to both hydrogel types were increased rapidly in 10 min. and remained consistently in 90 min. Decreasing of interfacial energetics was taken slowly up to an hour in spite of rapid diffusion of protein molecules. This is due to the fact that water deprivation from three dimensional interphase initially formed by protein diffusion took over an hour. Interpretation of adsorption kinetics on contact lens hydrogels was discussed with understanding of relationship between surface energy and protein adsorption capacity.
BI-TuP-3 For the Development of Auto-Injection System to Cells: Coating of Inserting Pipettes, Gas-Flow Evaluation Method for Prepared Pipettes, and SPM-inspired Pipette-Top Sensing System
Tomohide Takami, Jun-ichi Uewaki, Hiroshi Ochiai (Hiroshima University, Japan); Masato Koyama, Yoshihide Ogawa, Mikako Saito, Hideaki Matsuoka (Tokyo University of Agriculture & Technology, Japan); Yoshihiro Ojiro, Kiwamu Nishimoto, Shuichi Ogawa, Yuji Takakuwa (Tohoku University, Japan); Shin-ichi Tate (Hiroshima University, Japan)

Glass nanopipettes have been used as a bridge to connect macro world and micro world.[1] They can be used as an ion-selective probe,[2-6] and as an injector to deposit a small amount of materials onto a surface.[7]

Injection to cell is a hot topic for the statistical experiments on the live dynamics of injected molecules in cell as well as the application to genetic engineering. Several auto-injection systems are already commercially available. However, the fatal problem of these auto-injection systems is the viability of cells after the injection; usually less than 10%.

We have been developing an auto-injection system in which the distance between the injecting pipette tip top and the cell is monitored and the signal depending on the pipette-cell distance is put into the feedback system to achieve the controlled insertion/extracion motion of the pipette to the cell in order to increase the viability of cells. This system is inspired from scanning tunneling microscopy on which the tip-sample distance is well-controlled for the nanoscale observation and molecular manipulation.[8]

Also, we have developed two methods for the auto-injection. One is the coating of the pipette top with chlorobenzene-terminated polysiloxane to reduce the damage to the inserted cell. The other is the gas-flow method to evaluate the inner diameter and the shank length of the pipette before using since the pipettes after the observation with electron microscope cannot be used.

In this paper, we will show our progress to realize the auto-injection system for the use of statistic and quantitative studies. We will demonstrate the ability of manual injection system to show the limit of the manual injection study. We will also demonstrate how the surface science technologies including scanning probe microscopy (SPM), surface coating, and vacuum science can be utilized for the development of the auto-injection system.

[1] T. Takami, B. H. Park, and T. Kawai, Nano Convergence 1, 17 (2014) [review paper].

[2] J.W. Son, T. Takami, J.-K. Lee, B.H. Park, and T. Kawai, Appl. Phys. Lett., 99, 033701 (2011).

[3] X.L. Deng, T. Takami, J.W. Son, T. Kawai, and B.H. Park, Appl. Phys. Express5, 027001 (2012).

[4] T. Takami, F. Iwata , K. Yamazaki , J.W. Son , J.-K. Lee , B.H. Park , and T. Kawai, J. Appl. Phys., 111, 044702 (2012).

[5] X.L. Deng, T. Takami, J.W. Son, E.J. Kang, T. Kawai, and B.H. Park, Journal of Nanoscience and Nanotechnology, 13, 5413-5419 (2013).

[6] E.J. Kang, T. Takami, X.L. Deng, J.W. Son, T. Kawai, and B.H. Park, J. Chem. Phys. B118, 5130-5134 (2014).

[7] F. Iwata, S. Nagami, Y. Sumiya and A. Sasaki, Nanotechnology18, 105301 (2007).

[8] T. Takami, e-J. Surf. Sci. Nanotech. 12, 157–164 (2014) [review paper].

BI-TuP-4 Correlative Imaging of Single Mammalian Cells in their Native Environments
Xin Hua, Craig Szymanski, Zhaoying Wang, Bingwen Liu, Zihua Zhu, James Evans, Galya Orr (Pacific Northwest National Laboratory); Songqin Liu (Southeast University, China); Xiaoying Yu (Pacific Northwest National Laboratory)

Mammalian cell analysis is of significant importance in providing detailed insights into biological system activities. Due to the complexity and heterogeneity of mammalian cell behavior and the technical challenge of spatially mapping chemical components in a hydrated environment, correlative chemical imaging from multiplexed measurement platforms is needed. Fluorescence structured illumination microscope (SIM), with super high resolution and visualization of proteins and sub-cellular structures in 3-D, provides more detailed information in cell structure and dynamics. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a unique surface-sensitive tool that provides molecular information and chemical mapping with a sub-micron lateral resolution. However, the understanding of how the spatial heterogeneity and structural difference affect the mammalian cell activities in an unperturbed, hydrated state by ToF-SIMS is severely limited due to the challenge to detect liquids with high volatility in high vacuum using surface sensitive surface techniques.

We recently developed a novel microfluidic reactor enabling correlative imaging of single mammalian cell (e.g., C10 mouse lung epithelial cell) growth by SIM and ToF-SIMS. Cells were introduced in the microchannel, incubated at 37 oC for 24 hr., fed with 5 Nm quantum dots, and then fixed with 4% paraformaldehyde before SIM imaging. In subsequent ToF-SIMS analysis, an aperture of 2 µm in diameter was drilled through the SiN membrane to form a detection window to image biological surfaces directly; and surface tension is used for holding the liquid within the aperture.

SIM images show that cells are successfully cultured on the SiN membrane, and quantum dots are uptaken by cells and dispersed in the cytoplasm. The ToF-SIMS m/z spectra were compared among dried cell samples, hydrated cells, and medium solution. Characteristic lipid fragments are identified. Moreover, 2D mapping of representative cell fragments were obtained. In addition, depth profiling was used to provide time- and space-resolved imaging of the single cell inside the microchannel. Furthermore, principal component analysis is conducted to evaluate the intrinsic similarities and discriminations among samples. Our results demonstrate the feasibility for in situ imaging of single mammalian cells in the hydrated state using ToF-SIMS for the first time. Correlative imaging using SIM and ToF-SIMS provides much sought-after information across different space scales for investigating cell dynamics. This novel approach has great potential for studying intracellular processes in the future.

BI-TuP-5 Nano-Bio Interfacial Analysis using time-of-flight Medium Energy Ion Scattering
KwangWon Jung (DGIST, Korea, Republic of Korea); KyungSoo Park (KMAC, Republic of Korea); WonJa Min (KMAC); HeeJin Lim, SanJoon Moon (DGIST, Korea); DaeWon Moon (DGIST, Korea, Republic of Korea)

We have developed a TOF-MEIS system using 70~100 keV He+. A TOF-MEIS system was designed and constructed to minimize the ion beam damage effect by utilizing a pulsed ion beam with a pulse width < 1 ns and a TOF delay-line-detector with an 120 mm diameter and a time resolution of 180 ps. The TOF-MEIS is an useful tool for interfacial analysis of the composition and structure of nano and bio systems. Our recent applications are reported.

#1) UltraShallow Junction: As doped Si ultra shallow junctions were fabricated with various annealing conditions. We measured the compositional depth profile of 2 x 1015 atoms/cm2 As doped silicon (annealed/unannealed) by the random and channelling phenomenon in Si(100) lattice. The result clearly indicates that the As dopant profile depends on the annealing temperature and conditions. Monitoring of As activated/deactivated ratio in ultra shallow junction by TOF-MEIS will be beneficial to the manufacturing processes of semiconductor industry.

#2) NanoParticles: We measured the quantitative compositional profiling with single atomic layer resolution for 0.5~3 nm CdSe/ZnS QDs with a conjugated layer. We also investigated the effect with Polyaspartic Acid (pAsp) and Osteocalcin on the initial bone growth of calcium hydroxyl appatite on a carboxyl terminated surface. When pAsp is not added to the self-assembled monolayers of Ca 2mM with Phosphate 1.2 mM, the growth procedure of calcium hydroxyl appatite cannot be monitored due to its rapid growth. When pAsp is added to the SAMs, the initial grow stage of the Ca-P can be monitored so that the chemical composition and their nucleus size can be analyzed.

#3) Liquid interface: Using a graphene as a MEIS analysis window, the electric double layer structure of liquid interface was depth profiled with atomic layer depth resolution. The electric double layer of KI solution is reported with discussions on further studies.

BI-TuP-6 Investigation on the Effect of the Moisture on the Formation of Self-Lubricant Films of H3BO3 Obtained at the Surface of a Metal with Biomedical Applications
Enrique Hernández-Sánchez (Instituto Politécnico Nacional-UPIBI, Mexico); Yesica Domínguez-Galicia (Instituo Politécnico Nacional-UPIBI, Mexico); Carlos Orozco-Álvarez (Instituto Politécnico Nacional-UPIBI, Mexico); Hector Herrera-Hernández (Universid Autónoma del Estado de México, Mexico); Julio Velázquez (Instituto Politécnico Nacional-ESIQUIE, Mexico); Alexis Chino-Ulloa (Instituto Politécnico Nacional-UPIBI, Mexico)

This study evaluates the effect of the environmental moisture during the formation of a thin film of boric acid. The study was conducted on AISI 316L stainless steel because of its biomedical applications. First the samples were exposed to boriding process in order to generate a continuous surface layer of iron boride. Then, the samples were exposed to a Short Annealing Process (SAP) at 1023 K during 5 min and cooled to room temperature at five different conditions of moisture. The purpose of SAP was to promote the formation of a surface film of boric acid. During SAP, the boron contained in the exposed borided layers undergoes oxidation and forms a layer of boron oxide. During cooling, this layer undergoes a secondary chemical reaction with the environmental moisture to form a thin boric acid film. The presence of the boric acid at the surface of the borided layer was corroborated by means of Raman Spectroscopy and X Ray Diffraction. The results showed that the sample with the highest moisture during the cooled process exhibited also the most compact film of boric acid. Finally, the friction coefficient of the samples was evaluated before and after of SAP and the results indicated a clear influence of moisture on its values since the lowest values of friction coefficient were achieved with the highest values of moisture.

BI-TuP-7 Electrochemical Deposition of Natural Melanin Composites for Biocompatible Electrodes
Taesik Eom (Inha University, South Korea)
Development of biocompatible functional materials is essential for the research of implantable bioelectronics and machine – tissue hybrid engineering. Among them, electrically conducting materials are one of the least biocompatible materials because conventional conductors such as metals and ceramics cause foreign-body reaction problems. To overcome this issue, naturally occurring conducting materials such as melanin, β-carotene, indigo, tyrian purple, and beyond are now receiving attention because their conjugate backbone structures provide conducting pathways. Among them, we used natural melanin from Sepia officinalis and synthesized biocompatible conducting composites of melanin by electrochemical polymerization methods such as utilizing (3,4-ethylenedioxythiophene) (EDOT) and synthetic melanin precursor. We further demonstrate the nanostructures, electrical properties, and biocompatibility of resulting composites by scanning electron microscope (SEM), electrochemical impedance measurement, and in vitro cell test of PC12, respectively.
BI-TuP-8 Cell-free Photosynthetic System Fabricated by Layer-By-Layer Assembly
Hongsup Hwang (Inha University, Republic of Korea)
Photosynthesis is an energy conversion process that all the living organisms derive their chemical and biological energy either directly or indirectly from sunlight. Light conversion mechanism of photosynthesis has been researched for more than 70 years and it is now actively pursued to utilize in an artificial device by using such as thylakoid membranes. However, the naturally occurred thylakoids are not stable enough to sustain their functionality in an artificial system. In our study, polymer-thylakoid nanostructured films were fabricated by immobilizing the thylakoid membrane particles on the substrate by the layer-by-layer assembly technique. The resulting film showed stable photoelectrochemical activities for weeks. We further investigated the properties of the thylakoid composite film utilizing a scanning electron microscopy (SEM), a zeta potential, and a UV-Vis spectroscopy. In addition, the sustained photosynthesis ability of the film was assessed by directly measuring oxygen concentrations. The resulting thylakoid film will suggest a natural functional material options to be applied in the fields of organic bioelectronics, bioreactors, and biosensors.
BI-TuP-9 Wettability Of Biocompatible Calcium Phosphate
Magdalena Méndez-González (ESFM-National Polytechnic Institute of Mexico); Gabriela Méndez (Technological University of San Juan del Rio, Queretaro, Mexico)

Since wettability is a surface characteristic defined by the hydrophilic or hydrophobic behavior of the material, it is determinant for the interaction of biomaterials with biomolecules or for cells adhesion. The present work determinates the wettability of three different liquids that are involved in biological issues that were tested on pills of calcium phosphate synthesized by chemical precipitation. This determination was made by the measurement of the contact angle, which gave us the corresponding angles to each solution and pressure of the pills. It was concluded that exist a direct relation between the pressures at which the pills were fabricated and the contact angle. Also it was noted that the characteristics of the solutions influence in the calcium phosphates wettability. In the three cases as the pressure increases the contact angles do it to. This behavior due the pressure decreases the space between the calcium phosphates particles. The three liquids tested have the hydrophilic behavior that is desirable for a biomaterial because it is less than 65⁰. For further uses is better to used pills of calcium phosphate made at 1 Ton due have them a more hydrophilic behavior.

BI-TuP-10 Enhancing Protein Adsorption Simulations by Using Accelerated Molecular Dynamics
Herbert Urbassek, Christian Muecksch (Physics Department, University of Kaiserslautern, Kaiserslautern, Germany)

The atomistic modeling of protein adsorption on surfaces is hampered by the different time scales of the simulation (<< 1 ms) and experiment (up to hours), and the accordingly different ‘final’ adsorption conformations. We provide evidence that the method of accelerated molecular dynamics is an efficient tool to obtain equilibrated adsorption states. As a model system we study the adsorption of the protein BMP-2 on graphite in an explicit salt water environment. We demonstrate that due to the considerably improved sampling of conformational space, accelerated molecular dynamics allows to observe the complete unfolding and spreading of the protein on the hydrophobic graphite surface. This result is in agreement with the general finding of protein denaturation upon contact with hydrophobic surfaces.

Time Period TuP Sessions | Topic BI Sessions | Time Periods | Topics | PacSurf2014 Schedule