P(VDF‐TrFE)/BaTiO<sub>3</sub> Nanoparticle Composite Films Mediate Piezoelectric Stimulation and Promote Differentiation of SH‐SY5Y Neuroblastoma Cells

Chen

et al. 2020

Adv Funct Materials

Precise neural electrical stimulation, which is a means of promoting neuronal regeneration, is a promising solution for patients with neurotrauma and neurodegenerative diseases. In this study, wirelessly controllable targeted motion and precise stimulation at the single‐cell level using S.platensis@Fe3O4@tBaTiO3 micromotors are successfully demonstrated for the first time. A highly versatile and multifunctional biohybrid soft micromotor is fabricated via the integration of S.platensis with magnetic Fe3O4 nanoparticles and piezoelectric BaTiO3 nanoparticles. The results show that this micromotor system can achieve navigation in a highly controllable manner under a low‐strength rotating magnetic field. The as‐developed system can achieve single‐cell targeted motion and then precisely induce the differentiation of the targeted neural stem‐like cell by converting ultrasonic energy to an electrical signal in situ owing to the piezoelectric effect. This new approach toward the high‐precision stimulation of neural stem‐like cells opens up new applications for micromotors and has excellent potential for precise neuronal regenerative therapies.

Section: Resultsmentioning

confidence: 99%

Wireless Manipulation of Magnetic/Piezoelectric Micromotors for Precise Neural Stem‐Like Cell Stimulation

Chen

et al. 2020

Adv Funct Materials

Adv Materials Technologies

“…To verify that P(VDF‐TrFE) in the fibers is indeed in the ferroelectric phase, X‐ray diffraction (XRD) patterns of the electrospun P(VDF‐TrFE) fibers before and after the stretching process are shown in Figure e, and fitting of the patterns can reveal the quantification of each phase (shown in Figure S3, Supporting Information) . Both samples exhibit identical peaks at 2θ = 17.14° corresponding to (200)/(110) peak of the α‐phase, 2θ = 19.98° corresponding to (200)/(110)peak of the β‐phase, and 2θ = 18.73° corresponding to amorphous phase, respectively.…”

Section: Resultsmentioning

confidence: 99%

Highly Oriented Electrospun P(VDF‐TrFE) Fibers via Mechanical Stretching for Wearable Motion Sensing

Zhang

et al. 2018

materials, piezoelectric materials, which can convert mechanical shape changes into electric outputs, are particularly favorable to fabricate wearable devices for mechanicalrelated sensing and power generation. [15][16][17] According to material molecular compositions, piezoelectric materials are generally divided into ceramics and polymers. Indeed, even though inorganic piezoelectric materials offer high piezoelectric property, they are mechanically hard and brittle, which have difficulties to be directly applied to wearable devices. Besides, many piezoelectric ceramics contain heavy metal elements such as lead, that are harmful to human and environment. [18][19][20] On the other hand, piezoelectric polymers, represented by polyvinylidene fluoride (PVDF) and its copolymer poly[(vinylidenefluoride-cotrifluoroethylene] (P(VDF-TrFE)), are more preferable for wearable devices as they are lightweight, stretchable, environmentfriendly and chemically stable. [21,22] To construct piezoelectric polymer fibers, electrospinning, as a representative template-free method, [23,24] is a versatile technique to produce extended length of fiber-shaped structures with a number of advantages such as large surface area, tunable surface morphologies, and enhanced mechanical performance. [25][26][27][28] With electrospinning, when the droplet of polymer solution is charged by high applied voltage, the liquid droplet is pulled into a thin fiber and then collected by the grounded electrode. However, this liquid-to-solid transferring process normally results in randomly distributed fibers with poor electrical properties and limited response to mechanical stimuli. Therefore, to improve the performance of electrospun fibers, several methods have been demonstrated to obtain aligned electrospun fibers. [29][30][31][32][33] Two most frequently adopted methods are: 1) using a high-speed rotating collector with a very sharp edge, [34][35][36] and 2) using two separated parallel electrodes. [37,38] A very high rotating speed (>3000 rpm) is necessary for the rotating collector method, which brings high requirements to the fabrication facilities and increases electricity consumption. Also, the necessary role of sharp edge further restricts the amount of highly aligned electrospun fibers that can be collected. The parallel electrode method, on the other hand, can only fabricate aligned electrospun fibers in a very limited length, typically on millimeter scale.Advances in functional fabrics enable the realization of wearable devices in the form factor of fibers that can be seamlessly adapted in our daily lives. For mechanical-related sensing and power generation, piezoelectric materials are particularly favorable because they can convert mechanical shape changes into electric outputs. Electrospinning is a widely applied technique to produce extended length of fiber-shaped piezoelectric devices. However, this versatile process normally results in randomly distributed fibers with poor electrical properties and limited response to mechanical stimuli. H...

“…Other investigations have reported that under ultrasonic stimulation, the charges generated by piezoelectric materials can be used to induce differentiation of neuronal cells. [ 5,17 ] Our magnetoelectric stimulation could provide an alternative method of stimulating the neuronal cells in a less invasive and gentler manner. Physical stimulation, such as ultrasonic and magnetic stimulation, may potentially minimize the use of expensive growth factors, when compared to other active cell delivery methods, [ 6e ] thus providing a more cost‐effective solution.…”

Section: Discussionmentioning

confidence: 99%

“…This microenvironment should approximate the physiological conditions of the soft extracellular matrix, as the differentiation of neuronal cells is influenced by the substrate stiffness. [ 5 ] Once their tasks have been completed, the safest way to remove these devices from the body is to let them degrade into nontoxic products that can be metabolized and/or excreted. [ 3a,c,6 ] However, most of the reported cell‐transporting microrobots are made of hard materials, which fail to provide a supportive and/or stimulating microenvironment for the cells, or to degrade once they have accomplished their delivery tasks.…”

Section: Introductionmentioning

confidence: 99%

3D‐Printed Soft Magnetoelectric Microswimmers for Delivery and Differentiation of Neuron‐Like Cells

Dong

Wang

Chen

et al. 2020

Adv Funct Materials

173

177

Neurodegenerative diseases generally result in irreversible neuronal damage and neuronal death. Cell therapy shows promise as a potential treatment for these diseases. However, the therapeutic targeted delivery of these cells and the in situ provision of a suitable microenvironment for their differentiation into functional neuronal networks remain challenging. A highly integrated multifunctional soft helical microswimmer featuring targeted neuronal cell delivery, on-demand localized wireless neuronal electrostimulation, and post-delivery enzymatic degradation is introduced. The helical soft body of the microswimmer is fabricated by two-photon lithography of the photocurable gelatin-methacryloyl (GelMA)-based hydrogel. The helical body is then impregnated with composite multiferroic nanoparticles displaying magnetoelectric features (MENPs). While the soft GelMA hydrogel chassis supports the cell growth, and is degraded by enzymes secreted by cells, the MENPs allow for the magnetic transportation of the bioactive chassis, and act as magnetically mediated electrostimulators of neuron-like cells. The unique combination of the materials makes these microswimmers highly integrated devices that fulfill several requirements for their future translation to clinical applications, such as cargo delivery, cell stimulation, and biodegradability. The authors envision that these devices will inspire new avenues for targeted cell therapies for traumatic injuries and diseases in the central nervous system.