344 results match your criteria copolymer lithography


Crystallization Induced Self-Assembly: A Strategy to Achieve Ultra-Small Domain Size.

Chemistry 2021 Apr 8. Epub 2021 Apr 8.

South China University of Technology, School of Molecular Science and Engineering, 318 Wushan Road, 510640, Guangzhou, CHINA.

Achieving self-assembled nanostructures with ultra-small feature sizes (e.g., below 5 nm) is an important prerequisite for the development of block copolymer lithography. Read More

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Alternating Ring-Opening Metathesis Polymerization Provides Easy Access to Functional and Fully Degradable Polymers.

Macromolecules 2020 Jul 16;53(14):5857-5868. Epub 2020 Jul 16.

Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400.

Polymers with hydrolyzable groups in their backbones have numerous potential applications in biomedicine, lithography, energy storage and electronics. In this study, acetal and ester functionalities were incorporated into the backbones of copolymers by means of alternating ring-opening metathesis polymerization catalyzed by third-generation Grubbs ruthenium catalyst. Specifically, combining large-ring (7-10 atoms) cyclic acetal or lactone monomers with bicyclo[4. Read More

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Self-organization of Random-co-Polymers to Nanopatterns by Localized E-Beam Dosing.

Nanotechnology 2021 Mar 24. Epub 2021 Mar 24.

Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam, INDIA.

A strategic electron beam (e-beam) irradiation on the surface of a PS-PMMA random copolymer ultrathin (< 100 nm) film followed by solvent annealing stimulate a special variety of dewetting, leading to a large-area hierarchical nanoscale patterns. For this purpose, initially, a negative (positive) tone of resist PS (PMMA) under a weak e-beam exposure is exploited to produce an array of sites composed of crosslinked PS (chain-scissioned PMMA). Subsequently, annealing with the help of a developer solvent engenders dewetted patterns in the exposed zones where PMMA blocks are confined by the blocks of cross-linked PS. Read More

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High Performance Field-Effect Transistors Based on Partially Suspended 2D Materials via Block Copolymer Lithography.

Polymers (Basel) 2021 Feb 14;13(4). Epub 2021 Feb 14.

Department of Organic Materials and Fiber Engineering, Soongsil University, 369 Sangdo-ro, Dongjak-gu, Seoul 06978, Korea.

Although various two-dimensional (2D) materials hold great promise in next generation electronic devices, there are many challenges to overcome to be used in practical applications. One of them is the substrate effect, which directly affects the device performance. The large interfacial area and interaction between 2D materials and substrate significantly deteriorate the device performance. Read More

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February 2021

Hierarchical Self-Assembly of Thickness-Modulated Block Copolymer Thin Films for Controlling Nanodomain Orientations inside Bare Silicon Trenches.

Polymers (Basel) 2021 Feb 13;13(4). Epub 2021 Feb 13.

Department of Organic Materials and Fiber Engineering, Soongsil University 369 Sangdo-ro, Dongjak-gu, Seoul 06978, Korea.

We study the orientation and ordering of nanodomains of a thickness-modulated lamellar block copolymer (BCP) thin film at each thickness region inside a topological nano/micropattern of bare silicon wafers without chemical pretreatments. With precise control of the thickness gradient of a BCP thin film and the width of a bare silicon trench, we successfully demonstrate (i) perfectly oriented lamellar nanodomains, (ii) pseudocylindrical nanopatterns as periodically aligned defects from the lamellar BCP thin film, and (iii) half-cylindrical nanostructure arrays leveraged by a trench sidewall with the strong preferential wetting of the PMMA block of the BCP. Our strategy is simple, efficient, and has an advantage in fabricating diverse nanopatterns simultaneously compared to conventional BCP lithography utilizing chemical pretreatments, such as a polymer brush or a self-assembled monolayer (SAM). Read More

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February 2021

Replacing Metals with Oxides in Metal-Assisted Chemical Etching Enables Direct Fabrication of Silicon Nanowires by Solution Processing.

Nano Lett 2021 Mar 18;21(5):2310-2317. Epub 2021 Feb 18.

Laboratoire Chimie de la Matière Condensée de Paris (LCMCP), Collège de France, CNRS, Sorbonne Université, F-75005 Paris, France.

Metal-assisted chemical etching (MACE) has emerged as an effective method to fabricate high aspect ratio nanostructures. This method requires a catalytic mask that is generally composed of a metal. Here, we challenge the general view that the catalyst needs to be a metal by introducing oxide-assisted chemical etching (OACE). Read More

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Electrokinetic identification of ribonucleotide monophosphates (rNMPs) using thermoplastic nanochannels.

J Chromatogr A 2021 Feb 8;1638:461892. Epub 2021 Jan 8.

Department of Chemistry, The University of Kansas, Lawrence, KS 66045; Center of Biomodular Multiscale Systems for Precision Medicine; Sunflower Genomics, Inc. Lawrence, KS 66047; Department of Mechanical Engineering, The University of Kansas, Lawrence, KS 66045; Bioengineering Program, The University of Kansas, Lawrence, KS 66045; KU Cancer Center, University of Kansas Medical Center, Kansas City, KS 66160. Electronic address:

With advances in the design and fabrication of nanofluidic devices during the last decade, there have been a few reports on nucleic acid analysis using nanoscale electrophoresis. The attractive nature of nanofluidics is the unique phenomena associated with this length scale that are not observed using microchip electrophoresis. Many of these effects are surface-related and include electrostatics, surface roughness, van der Waals interactions, hydrogen bonding, and the electric double layer. Read More

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February 2021

Optical Properties of Site-Selectively Grown InAs/InP Quantum Dots with Predefined Positioning by Block Copolymer Lithography.

Materials (Basel) 2021 Jan 14;14(2). Epub 2021 Jan 14.

DTU Fotonik, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.

The InAs/InP quantum dots (QDs) are investigated by time-integrated (PL) and time-resolved photoluminescence (TRPL) experiments. The QDs are fabricated site-selectively by droplet epitaxy technique using block copolymer lithography. The estimated QDs surface density is ∼1. Read More

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January 2021

Engineering a Robust Flat Band in III-V Semiconductor Heterostructures.

Nano Lett 2021 Jan 18;21(1):680-685. Epub 2020 Dec 18.

Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, 59000 Lille, France.

Electron states in semiconductor materials can be modified by quantum confinement. Adding to semiconductor heterostructures the concept of lateral geometry offers the possibility to further tailor the electronic band structure with the creation of unique flat bands. Using block copolymer lithography, we describe the design, fabrication, and characterization of multiorbital bands in a honeycomb InGaAs/InP heterostructure quantum well with a lattice constant of 21 nm. Read More

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January 2021

Confinement and Processing Can Alter the Morphology and Periodicity of Bottlebrush Block Copolymers in Thin Films.

ACS Nano 2020 Nov 23. Epub 2020 Nov 23.

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.

Bottlebrush block copolymers (BBCPs) are intriguing architectural variations on linear BCPs with highly tunable structure. Confinement can have a significant impact on polymer assembly, giving rise to changes in morphology, assembly kinetics, and properties like the glass transition. Given that confinement leads to significant changes in the persistence length of bottlebrush homopolymers, it is reasonable to expect that BBCPs will see significant changes in their structure and periodicity relative to the bulk morphology. Read More

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November 2020

The Influence of Additives on the Interfacial Width and Line Edge Roughness in Block Copolymer Lithography.

Chem Mater 2020 ;32(6)

Materials Science and Engineering Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899.

The challenges of patterning next generation integrated circuits have driven the semiconductor industry to look outside of traditional lithographic methods in order to continue cost effective size scaling. The directed self-assembly (DSA) of block copolymers (BCPs) is a nanofabrication technique used to reduce the periodicity of patterns prepared with traditional optical methods. BCPs with large interaction parameters (), provide access to smaller pitches and reduced interface widths. Read More

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January 2020

Synthesis of Metal-Capped Semiconductor Nanowires from Heterodimer Nanoparticle Catalysts.

J Am Chem Soc 2020 Oct 20;142(43):18324-18329. Epub 2020 Oct 20.

Semiconductor nanowires (NWs) capped with metal nanoparticles (NPs) show multifunctional and synergistic properties, which are important for applications in the fields of catalysis, photonics, and electronics. Conventional colloidal syntheses of this class of hybrid structures require complex sequential seeded growth, where each section requires its own set of growth conditions, and methods for preparing such wires are not universal. Here, we report a new and general method for synthesizing metal-semiconductor nanohybrids based on particle catalysts, prepared by scanning probe block copolymer lithography, and chemical vapor deposition. Read More

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October 2020

Monolithic digital patterning of polydimethylsiloxane with successive laser pyrolysis.

Nat Mater 2021 01 17;20(1):100-107. Epub 2020 Aug 17.

Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, Seoul, Korea.

The patterning of polydimethylsiloxane (PDMS) into complex two-dimensional (2D) or 3D shapes is a crucial step for diverse applications based on soft lithography. Nevertheless, mould replication that incorporates time-consuming and costly photolithography processes still remains the dominant technology in the field. Here we developed monolithic quasi-3D digital patterning of PDMS using laser pyrolysis. Read More

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January 2021

Coalescence-Driven Verticality in Mesoporous TiO Thin Films with Long-Range Ordering.

J Am Chem Soc 2020 Sep 2;142(37):15815-15822. Epub 2020 Sep 2.

International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan.

Mesoporous semiconducting films with continuous interconnectivity and minimal tortuosity, such as densely ordered arrays of vertical channels, are ideal for ensuring a maximal surface area at the heterojunction to increase the density of charges or photons. While the design of these films with nanostructures below 50 nm using modern lithography is not feasible, continuously perpendicular pores can be obtained throughout a TiO film using a traditional soft-templating approach and lyotropic crystal engineering. We demonstrate here that a polystyrene--poly(ethylene oxide) block copolymer in a three-solvent system can self-assemble into a body-centered cubic template. Read More

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September 2020

Highly asymmetric lamellar nanostructures from nanoparticle-linear hybrid block copolymers.

Nanoscale 2020 Aug;12(31):16526-16534

Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.

The highly asymmetric lamellar (A-LAM) nanostructure is one of the most important template geometries for block copolymer (BCP) lithography. However, A-LAM is unattainable from conventional BCPs, and there is no general molecular design strategy for A-LAM-forming BCP. Herein, a nanoparticle-linear hybrid BCP system is reported, which is designed based on the intramolecular crosslinking technique, as a remarkably effective platform to obtain the A-LAM morphology. Read More

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AlGaN Deep-Ultraviolet Light-Emitting Diodes with Localized Surface Plasmon Resonance by a High-Density Array of 40 nm Al Nanoparticles.

ACS Appl Mater Interfaces 2020 Aug 29;12(32):36339-36346. Epub 2020 Jul 29.

Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea.

We present a remarkable improvement in the efficiency of AlGaN deep-ultraviolet light-emitting diodes (LEDs) enabled by the coupling of localized surface plasmon resonance (LSPR) mediated by a high-density array of Al nanoparticles (NPs). The Al NPs with an average diameter of ∼40 nm were uniformly distributed near the AlGaN/AlGaN multiple quantum well active region for coupling 285 nm emission by block copolymer lithography. The internal quantum efficiency is enhanced by 57. Read More

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Seeded Growth of Large-Area Arrays of Substrate Supported Au Nanoparticles Using Citrate and Hydrogen Peroxide.

Langmuir 2020 Jun 12;36(24):6848-6858. Epub 2020 Jun 12.

Division of Solar Cell Technology, Department of Materials Sciences and Engineering, Uppsala University, P.O. Box 534, 751 21 Uppsala, Sweden.

While seeded growth of quasi-spherical colloidal Au nanoparticles (NPs) has been extensively explored in the literature, the growth of surface supported arrays of such particles has received less attention. The latter scenario offers some significant challenges, including the attainment of sufficient particle-substrate adhesion, growth-selectivity, and uniform mass-transport. To this end, a reaction system consisting of HAuCl, citrate, and HO is here investigated for the growth of supported arrays of 10 nm Au seeds, derived via block copolymer (BCP) lithography. Read More

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Enhanced Reduction of Thermal Conductivity in Amorphous Silicon Nitride-Containing Phononic Crystals Fabricated Using Directed Self-Assembly of Block Copolymers.

ACS Nano 2020 Jun 2;14(6):6980-6989. Epub 2020 Jun 2.

Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States.

Studies have demonstrated that the thermal conductivity (κ) of crystalline semiconductor materials can be reduced by phonon scattering in periodic nanostructures formed using templates fabricated from self-assembled block copolymers (BCPs). Compared to crystalline materials, the heat transport mechanisms in amorphous inorganic materials differ significantly and have been explored far less extensively. However, thermal management of amorphous inorganic solids is crucial for a broad range of semiconductor devices. Read More

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3D Micro/Nanopatterning of a Vinylferrocene Copolymer.

Molecules 2020 May 23;25(10). Epub 2020 May 23.

Institute of Chemistry and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany.

In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the filling of the imprint stamp and its subsequent detachment may impose some practical challenges. Here we explored thermal and reverse NIL patterning of polyvinylferrocene and vinylferrocene-methyl methacrylate copolymers to prepare complex non-spherical objects and patterns. While neat polyvinylferrocene was found to be unsuitable for NIL, freshly-prepared vinylferrocene-methyl methacrylate copolymers, for which identity and purity were established, have been structured into 3D-micro/nano-patterns using NIL. Read More

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Block Copolymer Derived Vertically Coupled Plasmonic Arrays for Surface-Enhanced Raman Spectroscopy.

ACS Appl Mater Interfaces 2020 May 6;12(20):23410-23416. Epub 2020 May 6.

Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin, The University of Dublin, Dublin 2, Ireland.

A surface-enhanced Raman spectroscopy sensing template consisting of gold-covered nanopillars is developed. The plasmonic slab consists of a perforated gold film at the base of the nanopillars and a Babinet complementary dot array on top of the pillars. The nanopillars were fabricated by the incorporation of an iron salt precursor into a self-assembled block copolymer thin film and subsequent reactive ion etching. Read More

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Self-aligned microfluidic contactless dielectrophoresis device fabricated by single-layer imprinting on cyclic olefin copolymer.

Anal Bioanal Chem 2020 Jun 5;412(16):3881-3889. Epub 2020 May 5.

Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA.

The trapping and deflection of biological cells by dielectrophoresis (DEP) at field non-uniformities in a microfluidic device is often conducted in a contactless dielectrophoresis (cDEP) mode, wherein the electrode channel is in a different layer than the sample channel, so that field penetration through the interceding barrier causes DEP above critical cut-off frequencies. In this manner, through physical separation of the electrode and sample channels, it is possible to spatially modulate electric fields with no electrode-induced damage to biological cells in the sample channel. However, since this device requires interlayer alignment of the electrode to sample channel and needs to maintain a thin interceding barrier (~ 15 μm) over the entire length over which DEP is needed (~ 1 cm), variations in alignment and microstructure fidelity cause wide variations in cDEP trapping level and frequency response across devices. Read More

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Spatial Control of the Self-assembled Block Copolymer Domain Orientation and Alignment on Photopatterned Surfaces.

ACS Appl Mater Interfaces 2020 May 9;12(20):23399-23409. Epub 2020 May 9.

Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.

Polarity-switching photopatternable guidelines can be directly used to both orient and direct the self-assembly of block copolymers. We report the orientation and alignment of poly(styrene--4-trimethylsilylstyrene) (PS--PTMSS) with a domain periodicity, , of 44 nm on thin photopatternable grafting surface treatments (pGSTs) and cross-linkable surface treatments (pXSTs), containing acid-labile 4--butoxystyrene monomer units. The surface treatment was exposed using electron beam lithography to create well-defined linear arrays of neutral and preferential regions. Read More

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Feature size control using surface reconstruction temperature in block copolymer lithography for InAs nanowire growth.

Nanotechnology 2020 Aug 24;31(32):325303. Epub 2020 Apr 24.

Solid State Physics, NanoLund, Lund University, Sweden.

Here we present a method to control the size of the openings in hexagonally organized BCP thin films of poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) by using surface reconstruction. The surface reconstruction is based on selective swelling of the P4VP block in ethanol, and its extraction to the surface of the film, resulting in pores upon drying. We found that the BCP pore diameter increases with ethanol immersion temperature. Read More

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Evolution of Dip-Pen Nanolithography (DPN): From Molecular Patterning to Materials Discovery.

Chem Rev 2020 Jul 22;120(13):6009-6047. Epub 2020 Apr 22.

Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, United States.

Dip-pen nanolithography (DPN) is a nanofabrication technique that can be used to directly write molecular patterns on substrates with high resolution and registration. Over the past two decades, DPN has evolved in its ability to transport molecular and material "inks" (e.g. Read More

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Micro-Pattern of Graphene Oxide Films Using Metal Bonding.

Micromachines (Basel) 2020 Apr 10;11(4). Epub 2020 Apr 10.

System-on-Chip Center, Electrical and Computer Engineering Department, Khalifa University of Science and Technology, Abu Dhabi 127788, UAE.

Recently, graphene has been explored in several research areas according to its outstanding combination of mechanical and electrical features. The ability to fabricate micro-patterns of graphene facilitates its integration in emerging technologies such as flexible electronics. This work reports a novel micro-pattern approach of graphene oxide (GO) film on a polymer substrate using metal bonding. Read More

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Enhancement of the second harmonic signal of nonlinear crystals by self-assembled gold nanoparticles.

J Chem Phys 2020 Mar;152(10):104711

Institute for Applied Physics and Center LISA, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.

In second harmonic generation (SHG), the energy of two incoming photons, e.g., from a femtosecond laser, can be combined in one outgoing photon of twice the energy, e. Read More

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Controllable Subtractive Nanoimprint Lithography for Precisely Fabricating Paclitaxel-Loaded PLGA Nanocylinders to Enhance Anticancer Efficacy.

ACS Appl Mater Interfaces 2020 Apr 20;12(13):14797-14805. Epub 2020 Mar 20.

National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.

Nanoimprint lithography presents a new strategy for preparing uniform nanostructures with predefined sizes and shapes and has the potential for developing nanosized drug delivery systems. However, the current nanoimprint lithography is a type of an additive nanofabrication method that has limited potential due to its restricted template-dependent innate character. Herein, we have developed a novel subtractive UV-nanoimprint lithography (sUNL) for the scalable fabrication of PLGA nanostructures with variable sizes for the first time. Read More

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Synthesis Based on a Preceramic Polymer and Alumina Nanoparticles via UV Lithography for High Temperature Applications.

Materials (Basel) 2020 Mar 4;13(5). Epub 2020 Mar 4.

King Abdulaziz City for Science and Technology, P.O. Box 6086, Riyadh 11442, Saudi Arabia.

Because of the increased demand for preceramic polymers in high-tech applications, there has been growing interest in the synthesis of preceramic polymers, including polysiloxanes and alumina. These polymers are preferred because of their low thermal expansion, conformability to surfaces over large areas, and flexibility. The primary objective was to evaluate the aspects of polymer-derived ceramic routs, focusing on the UV lithography process of preceramic polymers and the pyrolyzing properties of the final ceramics. Read More

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Multimetallic High-Index Faceted Heterostructured Nanoparticles.

J Am Chem Soc 2020 Mar 25;142(10):4570-4575. Epub 2020 Feb 25.

Multimetallic heterostructured nanoparticles with high-index facets potentially represent an important class of highly efficient catalysts. However, due to their complexity, they are often difficult to synthesize. Herein, a library of heterostructured, multimetallic (Pt, Pd, Rh, and Au) tetrahexahedral nanoparticles was synthesized through alloying/dealloying with Bi in a tube furnace at 900-1000 °C. Read More

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Modulating Tumor Cell Functions by Tunable Nanopatterned Ligand Presentation.

Nanomaterials (Basel) 2020 Jan 26;10(2). Epub 2020 Jan 26.

Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Robert Koch Str. 40, 37075 Göttingen, Germany.

Cancer comprises a large group of complex diseases which arise from the misrouted interplay of mutated cells with other cells and the extracellular matrix. The extracellular matrix is a highly dynamic structure providing biochemical and biophysical cues that regulate tumor cell behavior. While the relevance of biochemical signals has been appreciated, the complex input of biophysical properties like the variation of ligand density and distribution is a relatively new field in cancer research. Read More

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January 2020