Therapeutic agent loaded micro and nanoscale particles as high-velocity projectiles can penetrate cells and tissues, thereby serving as gene and drug delivery vehicles for direct and rapid internalization. Despite recent progress in developing micro/nanoscale ballistic tools, the underlying biophysics of how fast projectiles deform and penetrate cell membranes is still poorly understood. To understand the rate and size-dependent penetration processes, we present coarse-grained molecular dynamics simulations of the ballistic impact of spherical projectiles on lipid membranes. Our simulations reveal that upon impact, the projectile can pursue one of three distinct pathways. At low velocities below the critical penetration velocity, projectiles rebound off the surface. At intermediate velocities, penetration occurs after the projectile deforms the membrane into a tubular thread. At very high velocities, rapid penetration occurs through localized membrane deformation without tubulation. Membrane tension, projectile velocity and size govern which phenomenon occurs, owing to their positive correlation with the reaction force generated between the projectile and the membrane during impact. Two critical membrane tension values dictate the boundaries among the three pathways for a given system, due to the rate dependence of the stress generated in the membrane. Our findings provide broad physical insights into the ballistic impact response of soft viscous membranes and guide design strategies for drug delivery through lipid membranes using micro/nanoscale ballistic tools.
Last. Sinan Keten(NU: Northwestern University)H-Index: 34
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Abstract Ballistic performance of ultra-thin graphene membranes have recently been investigated at the micro and nanoscale. Two open questions that remain unanswered are, how graphitic plates behave when they can no longer be treated as a thin membrane, and how the projectile shape influences the perforation resistance of plates of varying thicknesses. Through coarse-grained molecular dynamics simulations, we show that beyond a critical plate thickness, a cylindrical projectile penetrates the pl...
Last. Sinan Keten(NU: Northwestern University)H-Index: 34
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Abstract Recent microscale ballistic experiments have revealed that multilayer graphene membranes exhibit exceptionally high ballistic limit velocity and specific penetration energy. A key feature contributing to the exceptional performance of these systems is the cone wave that develops at impact, which propagates radially at a very high speed for ultra-light and stiff graphene membranes, distributing the kinetic energy of the projectile away from the impact zone. Current theories on ballistic ...
Last. Sinan Keten(NU: Northwestern University)H-Index: 34
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Cellulose nanopaper exhibits outstanding stiffness, strength, and toughness that originate from the exceptional properties of constituent cellulose nanocrystals (CNCs). However, it remains challenging to link the nanoscale properties of rod-like CNCs and their structural arrangements to the macroscale performance of nanopaper in a predictive manner. Here we address this need by establishing an atomistically informed coarse-grained model for CNCs via a strain energy conservation paradigm and simu...
Last. Sinan Keten(NU: Northwestern University)H-Index: 34
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Abstract Graphene oxide (GO) shows promise as a nanocomposite building block due to its exceptional mechanical properties. While atomistic simulations have become central to investigating its mechanical properties, the method remains prohibitively expensive for large deformations and mesoscale failure mechanisms. To overcome this, we establish a coarse-grained (CG) model that captures key mechanical and interfacial properties, and the non-homogeneous effect of oxidation in GO sheets. The CG mode...
Last. Joseph Wang(UCSD: University of California, San Diego)H-Index: 173
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Direct and efficient intracellular delivery of enzymes to cytosol holds tremendous therapeutic potential while remaining an unmet technical challenge. Herein, an ultrasound (US)-propelled nanomotor approach and a high-pH-responsive delivery strategy are reported to overcome this challenge using caspase-3 (CASP-3) as a model enzyme. Consisting of a gold nanowire (AuNW) motor with a pH-responsive polymer coating, in which the CASP-3 is loaded, the resulting nanomotor protects the enzyme from relea...
Last. Joseph Wang(UCSD: University of California, San Diego)H-Index: 173
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Micro- and nanoscale robots that can effectively convert diverse energy sources into movement and force represent a rapidly emerging and fascinating robotics research area. Recent advances in the design, fabrication, and operation of micro/nanorobots have greatly enhanced their power, function, and versatility. The new capabilities of these tiny untethered machines indicate immense potential for a variety of biomedical applications. This article reviews recent progress and future perspectives of...
Abstract Analysis of peptide/protein–membrane interactions is central to delineating the regulatory mechanisms of many membrane-mediated biochemical processes associated with receptor signaling, molecular transport, membrane trafficking, cell–cell communication, organelle dynamics, membrane destabilization by cytotoxic toxins, and antimicrobial peptides. Among a wide-range of biophysical methods for studying the membrane interaction, dual polarization interferometry (DPI) combines supported lipi...
#1Szu-Pei Fu(NJIT: New Jersey Institute of Technology)H-Index: 2
#2Zhangli Peng(ND: University of Notre Dame)H-Index: 15
Last. Yuan-Nan Young(NJIT: New Jersey Institute of Technology)H-Index: 20
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Abstract Lipid bilayer membranes have been extensively studied by coarse-grained molecular dynamics simulations. Numerical efficiencies have been reported in the cases of aggressive coarse-graining, where several lipids are coarse-grained into a particle of size 4 ∼ 6 nm so that there is only one particle in the thickness direction. Yuan et al. proposed a pair-potential between these one-particle-thick coarse-grained lipid particles to capture the mechanical properties of a lipid bilayer membran...
#1Fernando Soto(UCSD: University of California, San Diego)H-Index: 22
#2Gregory L. Wagner(UCSD: University of California, San Diego)H-Index: 9
Last. Joseph Wang(UCSD: University of California, San Diego)H-Index: 173
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Herein we report a new design for acoustic nanoswimmers, making use of a nanoshell geometry that was synthesized using a sphere template process. Such shell-shaped nanomotors display highly efficient acoustic propulsion on the nanoscale by converting energy from the ambient acoustic field into motion. The propulsion mechanism of the nanoshell motors relies on acoustic streaming stress over the asymmetric surface to produce the driving force for motion. The shell-shaped nanomotors offer a high su...
#1Jinxing Li(UCSD: University of California, San Diego)H-Index: 36
#2Isaac Rozen(UCSD: University of California, San Diego)H-Index: 8
Last. Joseph Wang(UCSD: University of California, San Diego)H-Index: 173
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Autonomous propulsion at the nanoscale represents one of the most challenging and demanding goals in nanotechnology. Over the past decade, numerous important advances in nanotechnology and material science have contributed to the creation of powerful self-propelled micro/nanomotors. In particular, micro- and nanoscale rockets (MNRs) offer impressive capabilities, including remarkable speeds, large cargo-towing forces, precise motion controls, and dynamic self-assembly, which have paved the way f...
#1Shixin Li(China University of Petroleum)H-Index: 9
#2Zengshuai Yan(China University of Petroleum)H-Index: 4
Last. Tongtao Yue(China University of Petroleum)H-Index: 14
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ABSTRACT Mechanical forces acting on a plasma membrane are of essential importance to cellular functioning via inducing delicate change of the membrane shape with the underlying mechanism yet to be elucidated. Here, we introduce an oscillating nanoparticle (NP) interaction with a lipid bilayer membrane, using the coarse-grained simulation to investigate the dynamic membrane response to constrained mechanical stimulation, which is ubiquitous in biology. Our results demonstrate that, the membrane ...
Last. Sinan Keten(NU: Northwestern University)H-Index: 34
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Biomolecular semiflexible polymer networks with persistence lengths well above those of single polymeric chains serve important structural and adhesive roles in biology, biomaterials, food science and many other fields. While relationships between the structure and viscoelasticity of semiflexible polymer networks have been previously investigated, it remains challenging to systematically relate fibril and network properties to cohesive and adhesive properties that govern the function of these ma...
Last. Sinan Keten(NU: Northwestern University)H-Index: 34
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The Bouligand structure features a helicoidal (twisted plywood) layup of fibers that are uniaxially arranged in-plane and is a hallmark of biomaterials that exhibit outstanding impact resistance. Despite its performance advantage, the underlying mechanisms for its outstanding impact resistance remain poorly understood, posing challenges for optimizing the design and development of bio-inspired materials with Bouligand microstructures. Interestingly, many bio-sourced nanomaterials, such as cellul...
Abstract Cellulose nanocrystals (CNCs) is a new family of cellulose materials with outstanding mechanical and chemical properties that have been successfully demonstrated to have potential for many applications. Understanding the mechanical behavior of individual CNCs and their interaction at nanoscale is very important for improving the manufacturing process and mechanical performance of the resulting materials at macroscale. However, due to time and length scale limitations for both, experimen...