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Abstract
Free-standing nanofins or pillar meta-atoms are the most common constituent building blocks in metalenses and metasurfaces in general. Here, we present an alternative metasurface geometry based on high aspect ratio via-holes. We design and characterize metalenses comprising ultradeep via-holes in 5 μm thick free-standing silicon membranes with hole aspect ratios approaching 30:1. These metalenses focus incident infrared light into a diffraction-limited spot. Instead of shaping the metasurface optical phase profile alone, we engineer both transmitted phase and amplitude profiles simultaneously by inverse-designing the lens effective index profile. This approach improves the impedance match between the incident and transmitted waves, thereby increasing the focusing efficiency. The holey platform increases the accessible aspect ratio of optical nanostructures without sacrificing mechanical robustness. The high nanostructure aspect ratio also increases the chromatic group delay range attainable, paving the way for a generation of high aspect ratio ruggedized flat optics, including large-area broadband achromatic metalenses.
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Affiliation(s)
- Soon Wei Daniel Lim
- Harvard John A. Paulson School of Engineering and Applied Sciences, 9 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Maryna L Meretska
- Harvard John A. Paulson School of Engineering and Applied Sciences, 9 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Federico Capasso
- Harvard John A. Paulson School of Engineering and Applied Sciences, 9 Oxford Street, Cambridge, Massachusetts 02138, United States
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Di Trani N, Silvestri A, Wang Y, Demarchi D, Liu X, Grattoni A. Silicon Nanofluidic Membrane for Electrostatic Control of Drugs and Analytes Elution. Pharmaceutics 2020; 12:E679. [PMID: 32707665 PMCID: PMC7407659 DOI: 10.3390/pharmaceutics12070679] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023] Open
Abstract
Individualized long-term management of chronic pathologies remains an elusive goal despite recent progress in drug formulation and implantable devices. The lack of advanced systems for therapeutic administration that can be controlled and tailored based on patient needs precludes optimal management of pathologies, such as diabetes, hypertension, rheumatoid arthritis. Several triggered systems for drug delivery have been demonstrated. However, they mostly rely on continuous external stimuli, which hinder their application for long-term treatments. In this work, we investigated a silicon nanofluidic technology that incorporates a gate electrode and examined its ability to achieve reproducible control of drug release. Silicon carbide (SiC) was used to coat the membrane surface, including nanochannels, ensuring biocompatibility and chemical inertness for long-term stability for in vivo deployment. With the application of a small voltage (≤ 3 V DC) to the buried polysilicon electrode, we showed in vitro repeatable modulation of membrane permeability of two model analytes-methotrexate and quantum dots. Methotrexate is a first-line therapeutic approach for rheumatoid arthritis; quantum dots represent multi-functional nanoparticles with broad applicability from bio-labeling to targeted drug delivery. Importantly, SiC coating demonstrated optimal properties as a gate dielectric, which rendered our membrane relevant for multiple applications beyond drug delivery, such as lab on a chip and micro total analysis systems (µTAS).
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Affiliation(s)
- Nicola Di Trani
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (A.S.); (Y.W.); (X.L.)
- University of Chinese Academy of Science (UCAS), Shijingshan, 19 Yuquan Road, Beijing 100049, China
| | - Antonia Silvestri
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (A.S.); (Y.W.); (X.L.)
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy;
| | - Yu Wang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (A.S.); (Y.W.); (X.L.)
| | - Danilo Demarchi
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy;
| | - Xuewu Liu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (A.S.); (Y.W.); (X.L.)
| | - Alessandro Grattoni
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (A.S.); (Y.W.); (X.L.)
- Department of Surgery, Houston Methodist Hospital, Houston, TX 77030, USA
- Department of Radiation Oncology, Houston Methodist Hospital, Houston, TX 77030, USA
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Camiloti PR, Valdés F, Delforno TP, Bartacek J, Zaiat M, Jeison D. A membrane aerated biofilm reactor for sulfide control from anaerobically treated wastewater. Environ Technol 2019; 40:2354-2363. [PMID: 29448898 DOI: 10.1080/09593330.2018.1441329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/10/2018] [Indexed: 06/08/2023]
Abstract
A upflow anaerobic sludge blanket reactor was operated combined to a membrane aerated biofilm reactor for sulfate removal and for elemental sulfur reclamation. A commercial silicon tube was used as an oxygen delivery diffuser. The process achieved high rates of sulfide removal from the liquid phase (90%). The hydrogen sulfide removal was influenced by the pH value and at pH value of 7.5, 98% of the H2S was removed. The elemental sulfur was observed inside the membrane, with content in the biomass of 21%. Through the massive sequencing of the samples, the microbial community diversity and the stratification of biomass inside the silicon tube was demonstrated, confirming the presence of sulfide-oxidizing bacteria on the membrane wall. The most important genera found related to the sulfur cycle were Sulfuricurvum, Geovibrio, Flexispira and Sulforospirillum.
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Affiliation(s)
- Priscila Rosseto Camiloti
- a Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP) , São Carlos , SP , Brazil
| | - Freddy Valdés
- b Natural Resources Department, Universidad de La Frontera , Temuco , Chile
| | - Tiago Palladino Delforno
- c Microbial Resources Division, Research Center for Chemistry, Biology and Agriculture (CPQBA), Campinas University - UNICAMP , Campinas , SP , Brazil
| | - Jan Bartacek
- d Department of Water Technology and Environmental Engineering, Institute of Chemical Technology , Praga , Czech Republic
| | - Marcelo Zaiat
- a Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP) , São Carlos , SP , Brazil
| | - David Jeison
- e Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso , Valparaíso , Chile
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