The Use of Functionalized Silk Fibroin Films as a Platform for Optical Diffraction‐Based Sensing Applications
We report a set of bioactive DOEs microfabricated using functionalized silk fibroin films and proof-of-principle demonstrations for optical diffraction-based sensing applications including hydration sensing, biological concealment, therapeutic treatment, in vitro and in vivo drug release monitoring upon degradation. Critical design features that determine the diffractive efficiency and resulting sensing performance have been discussed via simulation and experiment. This work builds on the abilities to design diffractive optical elements that are optimized for sensing applications, reshaping silk – a natural protein – with simple yet precise patterning techniques and further functionalizing it biologically.
Zhitao Zhou, Zhifeng Shi, Xiaoqing Cai, Shaoqing Zhang, Stephanie G Corder, Xinxin Li, Yeshun Zhang, Guozheng Zhang, Liang Chen, Mengkun Liu, David L Kaplan, Fiorenzo G Omenetto, Ying Mao, Zhendong Tao, Tiger H Tao, “The Use of Functionalized Silk Fibroin Films as a Platform for Optical Diffraction‐Based Sensing Applications”, Advanced Materials 29, 1605471 (18 April 2017).-pdf
Precise Protein Photolithography (P3): High Performance Biopatterning Using Silk Fibroin Light Chain as the Resist
In this study, we report on a precise protein photolithography for high-performance biopatterning using the well-defined silk fibroin light chain as the basic resist material. Silk fibroin is mainly composed of two components, namely heavy chain (H-fibroin, ~85%, w/w) and light chain (l-fibroin, ≈15%, w/w), which are linked by a single disulfide bond between Cys-c20 of H-fibroin and Cys-172 of l-fibroin. Compared to silk fibroin and sericin proteins, l-fibroin has a well-defined molecular weight of ≈26 kDa. It also has a higher proportion of undifferentiated and hydrophilic amino acid composition than H-fibroin, which facilitates facile chemical modification for the synthesis of a variety of biologically and chemically functional photoresists.
Wanpeng Liu, Zhitao Zhou, Shaoqing Zhang, Zhifeng Shi, Justin Tabarini, Woonsoo Lee, Yeshun Zhang, SN Gilbert Corder, Xinxin Li, Fei Dong, Liang Cheng, Mengkun Liu, David L Kaplan, Fiorenzo G Omenetto, Guozheng Zhang, Ying Mao, Tiger H Tao, “Precise Protein Photolithography (P3): High Performance Biopatterning Using Silk Fibroin Light Chain as the Resist”, Advanced Science 29, 1605471 (18 April 2017).-pdf
Nanoscale probing of electron-regulated structural transitions in silk proteins by near-field IR imaging and nano-spectroscopy
We report on electron-regulated nanoscale polymorphic transitions in silk proteins revealed by near-field infrared imaging and nano-spectroscopy at resolutions approaching the molecular level. The ability to locally probe nanoscale protein structural transitions combined with nanometre-precision electron-beam lithography offers us the capability to finely control the structure of silk proteins in two and three dimensions. Our work paves the way for unlocking essential nanoscopic protein structures and critical conditions for electron-induced conformational transitions, offering new rules to design protein-based nanoarchitectures.
Nan Qin, Shaoqing Zhang, Jianjuan Jiang, Stephanie Gilbert Corder, Zhigang Qian, Zhitao Zhou, Woonsoo Lee, Keyin Liu, Xiaohan Wang, Xinxin Li, Zhifeng Shi, Ying Mao, Hans A Bechtel, Michael C Martin, Xiaoxia Xia, Benedetto Marelli, David L Kaplan, Fiorenzo G Omenetto, Mengkun Liu, Tiger H Tao, “Nanoscale probing of electron-regulated structural transitions in silk proteins by near-field IR imaging and nano-spectroscopy”, Nature Communications 7, 13079 (07 October 2016).-pdf
Inkjet printing of regenerated silk fibroin: From printable forms to printable functions
We investigate a different approach to biomaterials fabrication, developing a biomaterials approach where the system utility can be controllably reconfigured ab initio to enable multiple end uses. Using silk fibroin as the base biomaterial, a silk solution formulation was developed that can be doped with other components to generate a custom library of inkjet-printable, functional “silk inks” for use in sensing, therapeutics, and regenerative medicine. To illustrate this concept, different functional inks were generated and by the addition of nanoparticles, enzymes, antibiotics, growth factors, and antibodies during the printing process, with retention of functions.
Hu Tao, Benedetto Marelli, Miaomiao Yang, Bo An, M. Serdar Onses, John A. Rogers, David L. Kaplan, Fiorenzo G. Omenetto, “Inkjet printing of regenerated silk fibroin: From printable forms to printable functions”, Advanced Materials 27, 4273–4279 (05 August 2015).-pdf
Silk-based resorbable electronic devices for remotely controlled therapy and in vivo infection abatement
We present here a fully degradable, remotely controlled, implantable therapeutic device operating in vivo to counter a Staphylococcus aureus infection that disappears once its function is complete. This class of device provides fully resorbable packaging and electronics that can be turned on remotely, after implantation, to provide the necessary thermal therapy or trigger drug delivery. Such externally controllable, resorbable devices not only obviate the need for secondary surgeries and retrieval, but also have extended utility as therapeutic devices that can be left behind at a surgical or suturing site, following intervention, and can be externally controlled to allow for infection management by either thermal treatment or by remote triggering of drug release when there is retardation of antibiotic diffusion, deep infections are present, or when systemic antibiotic treatment alone is insufficient due to the emergence of antibiotic-resistant strains. After completion of function, the device is safely resorbed into the body, within a programmable period.
Hu Tao, Suk-Won Hwang, Benedetto Marellia, Bo Ana, Jodie E. Moreaua, Miaomiao Yanga, Mark A. Brencklea, Stanley Kimb, David L. Kaplana,c, John A. Rogers, and Fiorenzo G. Omenetto, “Silk-based resorbable electronic devices for remotely controlled therapy and in vivo infection abatement”, PNAS 111, 17385–17389 (09 December 2014).-pdf
Terahertz-field-induced insulator-to-metal transition in vanadium dioxide metamaterial
Here we report the observation of an insulator–metal transition in vanadium dioxide induced by a terahertz electric field. This is achieved using metamaterial-enhanced picosecond, high-field terahertz pulses to reduce the Coulomb-induced potential barrier for carrier transport. A nonlinear metamaterial response is observed through the phase transition, demonstrating that high-field terahertz pulses provide alternative pathways to induce collective electronic and structural rearrangements. The metamaterial resonators play a dual role, providing sub-wavelength field enhancement that locally drives the nonlinear response, and global sensitivity to the local changes, thereby enabling macroscopic observation of the dynamics. This methodology provides a powerful platform to investigate low-energy dynamics in condensed matter and, further, demonstrates that integration of metamaterials with complex matter is a viable pathway to realize functional nonlinear electro- magnetic composites.
Mengkun Liu, Harold Y Hwang, Hu Tao, Andrew C Strikwerda, Kebin Fan, George R Keiser, Aaron J Sternbach, Kevin G West, Salinporn Kittiwatanakul, Jiwei Lu, Stuart A Wolf, Fiorenzo G Omenetto, Xin Zhang, Keith A Nelson, Richard D Averitt, “Terahertz-field-induced insulator-to-metal transition in vanadium dioxide metamaterial”, Nature 487, 345–348 (19 July 2012).-pdf
A physically transient form of silicon electronics
A remarkable feature of modern silicon electronics is its ability to remain physically invariant, almost indefinitely for practical purposes. Although this characteristic is a hallmark of applications of integrated circuits that exist today, there might be opportunities for systems that offer the opposite behavior, such as implantable devices that function for medically useful time frames but then completely disappear via resorption by the body. We report a set of materials, manufacturing schemes, device components, and theoretical design tools for a silicon-based complementary metal oxide semiconductor (CMOS) technology that has this type of transient behavior, together with integrated sensors, actuators, power supply systems, and wireless control strategies. An implantable transient device that acts as a programmable nonantibiotic bacteriocide provides a system-level example.
Suk-Won Hwang, Hu Tao, Dae-Hyeong Kim, Huanyu Cheng, Jun-Kyul Song, Elliott Rill, Mark A Brenckle, Bruce Panilaitis, Sang Min Won, Yun-Soung Kim, Young Min Song, Ki Jun Yu, Abid Ameen, Rui Li, Yewang Su, Miaomiao Yang, David L Kaplan, Mitchell R Zakin, Marvin J Slepian, Yonggang Huang, Fiorenzo G Omenetto, John A Rogers, “A physically transient form of silicon electronics”, Science 337 (6102), 1640-1644, 2012. -pdf
Metamaterials on paper as a sensing platform
A paper-based metamaterial (MM) device, which can potentially be utilized for quantitative analysis in biochemical sensing applications is introduced. Proof-of-concept demonstrations are accomplished by patterning micrometer-sized MM reson¬ators on paper substrates and monitoring the resonance shift induced by placing different concentrations of glucose solution on the paper MM.
Hu Tao, Logan R Chieffo, Mark A Brenckle, Sean M Siebert, Mengkun Liu, Andrew C Strikwerda, Kebin Fan, David L Kaplan, Xin Zhang, Richard D Averitt, Fiorenzo G Omenetto, “Metamaterials on paper as a sensing platform”, Advanced Materials, 23: 3197–3201, 2011.-pdf
Microwave and terahertz wave sensing with metamaterials
We have designed, fabricated, and characterized metamaterial enhanced bimaterial cantilever pixels for far-infrared detection. Local heating due to absorption from split ring resonators (SRRs) incorporated directly onto the cantilever pixels leads to mechanical deflection which is readily detected with visible light. Highly responsive pixels have been fabricated for detection at 95 GHz and 693 GHz, demonstrating the frequency agility of our technique. We have obtained single pixel responsivities as high as 16,500 V/W and noise equivalent powers of 10−8 W/Hz1/2 with these first-generation devices.
Hu Tao, Emil A Kadlec, Andrew C Strikwerda, Kebin Fan, Willie J Padilla, Richard D Averitt, Eric A Shaner, X Zhang, “Microwave and terahertz wave sensing with metamaterials”, Optics Express Vol. 19, Issue 22, pp. 21620-21626 (2011). -pdf
Reconfigurable terahertz metamaterials
We demonstrate reconfigurable anisotropic metamaterials at terahertz frequencies where artificial “atoms” reorient within unit cells in response to an external stimulus. This is accomplished by fabricating planar arrays of split ring resonators on bimaterial cantilevers designed to bend out of plane in response to a thermal stimulus. We observe a marked tunability of the electric and magnetic response as the split ring resonators reorient within their unit cells. Our results demonstrate that adaptive metamaterials offer significant potential to realize novel electromagnetic functionality ranging from thermal detection to reconfigurable cloaks or absorbers.
Hu Tao, AC Strikwerda, K Fan, WJ Padilla, X Zhang, RD Averitt, “Reconfigurable terahertz metamaterials”, Physical Review Letters. 103, 147401, 2009.-pdf
A metamaterial absorber for the terahertz regime: Design, fabrication and characterizatio
We present a metamaterial that acts as a strongly resonant absorber at terahertz frequencies. Our design consists of a bilayer unit cell which allows for maximization of the absorption through independent tuning of the electrical permittivity and magnetic permeability. An experimental absorptivity of 70% at 1.3 terahertz is demonstrated. We utilize only a single unit cell in the propagation direction, thus achieving an absorption coefficient α=2000 cm-1. These metamaterials are promising candidates as absorbing elements for thermally based THz imaging, due to their relatively low volume, low density, and narrow band response.
Hu Tao, Nathan I Landy, Christopher M Bingham, Xin Zhang, Richard D Averitt, Willie J Padilla, “A metamaterial absorber for the terahertz regime: Design, fabrication and characterization”, Optics Express 16, 7181-7188 (2008).-pdf