Nanodisc Research Articles

Thermal stability analysis of functionally graded non-uniform asymmetric circular and annular nano discs: Size-dependent regularity and boundary conditions

In this article, the size-dependent thermal buckling analysis of nonuniform functionally graded asymmetric circular and annular nanodiscs is presented on the basis of Kirchhoff's plate theory, Eringen's nonlocal elasticity theory, and physical neutral plane. For the first time, the nonlocal regularity conditions and boundary conditions are obtained for the asymmetric discs. The thickness of the nanodiscs is assumed to be varying linearly and parabolically in the radial direction. The Power-law model is adopted to compute the temperature-independent effective mechanical properties of the functionally graded materials (FGMs). The size-dependent stability equation is obtained from Euler-Lagrange's equation which is derived from Hamilton's principle. This equation and corresponding boundary conditions are discretized by the differential quadrature method (DQM) and provide an eigenvalue problem. The numerical value of the lowest eigenvalue is reported as a critical temperature difference on the surfaces of the nanodiscs. The effects of various parameters such as nonlocal parameter, volume fraction index, nodal lines, and taper parameters for thickness variations are studied.

An in Silico Approach to Reveal the Nanodisc Formulation of Doxorubicin.

Molecular dynamic behaviors of nanodisc (ND) formulations of free doxorubicin (DOX) and DOX conjugated lipid prodrug molecules were investigated by molecular dynamics (MD) simulations. We have unveiled how formulation design affects the drug release profile and conformational stability of ND assemblies. Our simulation results indicate that free DOX molecules loaded in the ND system experienced rapid dissociation due to the unfavorable orientation of DOX attached to the lipid surface. It is found that DOX tends to form aggregates with higher drug quantities. In contrast, lipidated DOX-prodrugs incorporated in ND formulations exhibited sufficient ND conformational stability. The drug loading capacity is dependent on the type of lipid molecules grafted on the DOX-prodrug, and the drug loading quantities in a fixed area of NDs follow the order: DOX-BMPH-MP > DOX-BMPH-TC > DOX-BMPH-PTE. To gain further insight into the dynamic characteristics of ND formulations governed by different kinds of lipidation, we investigated the conformational variation of ND components, intermolecular interactions, the solvent accessible surface area, and individual MSP1 residue flexibility. We found that the global conformational stability of DOX-prodrug-loaded ND assemblies is influenced by the molecular flexibility and lipidated forms of DOX-prodrug. We also found that the spontaneous self-aggregation of DOX-prodrugs with increasing quantities on ND could reduce the membrane fluidity and enhance the conformational stability of ND formulations.

Cell-Free Synthesis of Human Endothelin Receptors and Its Application to Ribosome Display.

Engineering G-protein-coupled receptors (GPCRs) for improved stability or altered function is of great interest, as GPCRs consist of the largest protein family, are involved in many important signaling pathways, and thus, are one of the major drug targets. Here, we report the development of a high-throughput screening method for GPCRs using a reconstituted in vitro transcription-translation (IVTT) system. Human endothelin receptor type-B (ETBR), a class A GPCR that binds endothelin-1 (ET-1), a 21-residue peptide hormone, was synthesized in the presence of nanodisc (ND) composed of a phospholipid, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG). The ET-1 binding of ETBR was significantly reduced or was undetectable when other phospholipids were used for ND preparation. However, when functional ETBR purified from Sf9 cells was reconstituted into NDs, ET-1 binding was observed with two different phospholipids tested, including POPG. These results suggest that POPG likely supports the folding of ETBR into its functional form in the IVTT system. Using the same conditions as ETBR, whose three-dimensional structure has been solved, human endothelin receptor type-A (ETAR), whose three-dimensional structure remains unsolved, was also synthesized in its functional form. By adding POPG-ND to the IVTT system, both ETAR and ETBR were successfully subjected to ribosome display, a method of in vitro directed evolution that facilitates the screening of up to 1012 mutants. Finally, using a mock library, we showed that ribosome display can be applied for gene screening of ETBR, suggesting that high-throughput screening and directed evolution of GPCRs is possible in vitro.

Nanodisc-Mediated Conversion of Virustatic Antiviral Antibody to Disrupt Virus Envelope in Infected Cells.

Many antibody-based antivirals, including broadly neutralizing antibodies (bnAbs) against various influenza virus strains, suffer from limited potency. A booster of the antiviral activity of an antibody is expected to facilitate development of antiviral therapeutics. In this study, a nanodisc (ND), a discoidal lipid bilayer encircled by membrane scaffold proteins, is engineered to provide virucidal properties to antibodies, thereby augmenting their antiviral activity. NDs carrying the Fc-binding peptide sequence form an antibody-ND complex (ANC), which can co-endocytose into cells infected with influenza virus. ANC efficiently inhibits endosome escape of viral RNA by dual complimentary mode of action. While the antibody moiety in an ANC inhibits hemagglutinin-mediated membrane fusion, its ND moiety destroys the viral envelope using free hemagglutinins that are not captured by antibodies. Providing virus-infected host cells with the ability to self-eliminate by the synergistic effect of ANC components dramatically amplifies the antiviral efficacy of a bnAb against influenza virus. When the efficacy of ANC is assessed in mouse models, administration of ANCs dramatically reduces morbidity and mortality compared to bnAb alone. This study is the first to demonstrate the novel nanoparticle ANC and its role in combating viral infections, suggesting that ANC is a versatile platform applicable to various viruses.

IsenND: a fluorescent sensor for membrane binding and remodeling reactions

Nanodiscs (NDs) have emerged as an excellent platform for structural and functional characterizations of membrane proteins. We herein further engineered nanodisc as a robust fluorescent sensor to monitor membrane biochemical reactions. Specifically, we circularized nanodiscs via split GFP, and thereby created an intensity-based fluorescent sensor for detecting membrane binding and remodeling events in NDs (isenND). We demonstrated the use of isenND to study the action of several bacterial and eukaryotic membrane proteins on lipids bilayers.

Gene regulation using nanodiscs modified with HIF-1-α antisense oligonucleotides

Delivery of nucleic acids can be hindered by multiple factors including nuclease susceptibility and the lack of an appropriate delivery vehicle. With multiple nanotechnology scaffolds, lipid-based systems are the preferred choice because of its high biocompatibility and low toxicity. However, many lipid nanoparticle systems still have issues regarding stability, rapid clearance, and cargo leakage. Here, we demonstrate the use of a synthetic nanodisc (ND) scaffold functionalized with an anti-HIF-1-α antisense oligonucleotide (ASO) to reduce HIF-1-α mRNA transcript levels.

All-State Switching of the Mie Resonance of Conductive Polyaniline Nanospheres.

Polyaniline (PANI), a conductive polymer, is a promising active material for optical switching. In most studies, active switching has so far been realized only between two states, whereas PANI has a total of six states. The optical properties of nanoscale PANI in all six states have remained unclear. Herein we report on all-state switching of the Mie resonance on PANI nanospheres (NSs) and active plasmon switching on PANI-coated Au nanodisks (NDs). All-state switching of differently sized PANI NSs is achieved by proton doping/dedoping and electrochemical methods. Theoretical studies show that the scattering peaks of the individual PANI NSs originate from Mie resonances. All-state switching is further demonstrated on PANI-coated circular Au NDs, where an unprecedentedly large plasmon peak shift of ∼200 nm is realized. Our study not only provides a fundamental understanding of the optical properties of PANI but also opens the probability for developing high-performance dynamic media for active plasmonics.

Gene Regulation Using Nanodiscs Modified with HIF-1-α Antisense Oligonucleotides.

Delivery of nucleic acids can be hindered by multiple factors including nuclease susceptibility, endosome trapping, and clearance. Multiple nanotechnology scaffolds have offered promising solutions, and among these, lipid-based systems are advantageous because of their high biocompatibility and low toxicity. However, many lipid nanoparticle systems still have issues regarding stability, rapid clearance, and cargo leakage. Herein, we demonstrate the use of a synthetic nanodisc (ND) scaffold functionalized with an anti-HIF-1-α antisense oligonucleotide (ASO) to reduce HIF-1-α mRNA transcript levels. We prepared ND conjugates by using a mixture of phosphoglycerolipids with phosphocholine and phosphothioethanol headgroups that self-assemble into a ∼13 × 5 nm discoidal structure upon addition of a 22-amino-acid ApoA1 mimetic peptide. Optimized reaction conditions yield 15 copies of the anti-HIF-1-α ASO DNA covalently conjugated to the thiolated phospholipids using maleimide-thiol chemistry. We show that DNA-ND conjugates are active, nuclease resistant, and rapidly internalized into cells to regulate HIF-1-α mRNA levels without the use of transfection agents. DNA-ND uptake is partially mediated through Scavenger Receptor B1 and the ND conjugates show enhanced knockdown of HIF-1-α compared to that of the soluble ASOs in multiple cell lines. Our results demonstrate that covalently functionalized NDs may offer an improved platform for ASO therapeutics.

Enhanced fano resonance in asymmetric nano dimer for sensing applications

Fano resonance (FR) owns a sharp asymmetric line shape, low radiation loss and huge modification ability so that enhancing Fano resonance in asymmetric dimers is a topic of interest in nanophotonics and plasmonics, which has potentials in sensing applications. Here, we theoretically investigated the enhancement and tunability of Fano resonance in shape-asymmetric gold nanoring-nanodisk dimer through varying the size of nanodisk (ND) and polarization angle (θ). The intensity of this mode was significantly enhanced by changing the aforementioned parameters. Furthermore, we studied the performance of FR in terms of the quality factor (QF) and figure of merit (FoM). It is found that the QF (FoM) of this mode decreases (increases) exponentially (linearly) with increasing ND and θ. We explored the sensitivities of FR with maximum FoM to assess the capability of this mode in the detection of refractive index. Moreover, our design displays enhanced performance by increasing the size of ND and the polarization angle of the incident light offering another degree of freedom for exploring and modulating asymmetric dimers. This approach provides insights into the enhanced and tunable FR with remarkable potential in sensing and switching applications.

Synthesis and characterization of NiCo-X (X = OH, S, Se, P) nanodiscs and comparison of their electrocatalytic performances in an electrochemical sensing platform

In this paper, NiCo-X (X = OH, S, P, Se) nanodiscs (NDs) were synthesized. Firstly, nickel-cobalt hydroxide (NiCo-OH) precursors with a nanodisc-like structure were prepared by a hydrothermal method.

Nanodiscs: a versatile nanocarrier platform for cancer diagnosis and treatment.

Cancer therapy is a significant challenge due to insufficient drug delivery to the cancer cells and non-selective killing of healthy cells by most chemotherapy agents. Nano-formulations have shown great promise for targeted drug delivery with improved efficiency. The shape and size of nanocarriers significantly affect their transport inside the body and internalization into the cancer cells. Non-spherical nanoparticles have shown prolonged blood circulation half-lives and higher cellular internalization frequency than spherical ones. Nanodiscs are desirable nano-formulations that demonstrate enhanced anisotropic character and versatile functionalization potential. Here, we review the recent development of theranostic nanodiscs for cancer mitigation ranging from traditional lipid nanodiscs encased by membrane scaffold proteins to newer nanodiscs where either the membrane scaffold proteins or the lipid bilayers themselves are replaced with their synthetic analogues. We first discuss early cancer detection enabled by nanodiscs. We then explain different strategies that have been explored to carry a wide range of payloads for chemotherapy, cancer gene therapy, and cancer vaccines. Finally, we discuss recent progress on organic-inorganic hybrid nanodiscs and polymer nanodiscs that have the potential to overcome the inherent instability problem of lipid nanodiscs.

Studies of methanol electro-oxidation with ternary wet-chemically prepared ZCSO hexagonal nanodiscs with electrochemical approach

High performance acute toxic methanol sensor based on hydrothermally prepared hexagonal nanodiscs (NDs) of ZnO/CdO/SnO2 (ZnCdSnO2 or ZCSO) was fabricated onto glassy carbon electrode (GCE). The characterization of ZCSO NDs in-terms of functional group analysis, binding energy evaluation, oxidation states, optical absorbance, crystallinity, structural morphology, and elemental compositions were performed by FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), UV–visible spectroscopy, XRD, FESEM-coupled-EDS analysis respectively. The current versus concentration plot was exhibited linear on a wide range of methanol concentration (0.01 nM to 0.1 mM) clarified as linear dynamic methanol detection range (LDR). Considering the ZCSO NDs-coated surface area onto GCE over the slope of LDR, noticeable methanol sensor sensitivity (4.5475 µA µM−1 cm−2) was perceived. Besides this, a considerable lower limit (7.69 ± 0.38 pM) of detection at signal/noise = 3 is obtained. The overall results of methanol chemical sensor were found with satisfactory and acceptable results in terms of their reproducibility, sensitivity, stability, and response-time. Additionally, the assembled ZCSO NDs-coated electrode was validated with real environmental samples and result was found good and acceptable. On considering the outcome of applicability and the way of this sensor assembling, this unique method might be a potential technique in the field of portable sensor development for the safety of environmental and healthcare fields in a broad scale.

Ultrafast plasmon dynamics in asymmetric gold nanodimers

We theoretically investigate the effect of symmetry breaking on the ultrafast plasmon responses of Au nanodisk (ND) dimers by varying the diameter of one of the constituent nanodisks. In the case of a single ultrafast laser pulse, we demonstrate that the ultrafast responses of Au ND homodimer can be significantly modified due to the effect of symmetry breaking. The symmetric dimer shows a single broad spectral peak, whereas the size-asymmetric dimer shows three spectral peaks. The first system displays at most one temporal maximum and no beats in ultrafast temporal, whereas the second system may have three temporal maxima and two beats due to a combination of broken symmetry and the coherent superposition between various plasmon modes induced by the ultra-short laser pulse. Moreover, the shape of temporal dynamics of the size-asymmetric dimer is significantly deformed due to the excitation of local plasmon modes with different wavelength components. Furthermore, the decay time of the amplitude of the local field is longer and oscillates with a high frequency due to the narrower linewidth and red-shifted spectral peaks. We show that the ultrafast plasmon responses of both dimers can be controlled by varying the relative phase and time delays between a pair of two pulses. Our results will open new paths to understanding ultrafast plasmon responses in asymmetric heterodimers with suitable properties for different applications.

Integrated hydrothermal assisted green synthesis of ZnO nano discs and their water purification efficiency together with antimicrobial activity

The water microbial contamination is very common and different techniques are in practice for the decontamination purpose. The advance oxidation processes are being employed to mortify pathogens polluting drinking water. Heterogeneous photocatalysis under sunlight irradiation is a cost effective and remarkably proficient method for water purification. Zinc Oxide (ZnO) is a biocompatible material that has promising photo–oxidant activity. In this study, ZnO has been synthesized using Aloe vera (Av) extract assisted with hydrothermal approach. The nano disc structure of ZnO was characterized by XRD SEM, TEM, AFM, EDX, and FTIR techniques. The optical properties of ZnO@Av NDs (nano discs) evaluated by DRS and PL revealed their sunlight harvesting capability, as the calculated band gap value was 2.8 eV. The surface area and surface charge were measured by BET (5.34 m2g-1) and Zeta potential (+7.46 mV). The antibacterial activity of ZnO@Av NDs was studied against Salmonella typhimurium as a function of various process variables i.e., photocatalyst loading, sunlight exposure time, and bacterial inoculum size. The bactericidal reaction parameters were optimized statistically by Response Surface Methodology (RSM) on exposure to direct sunlight (average solar flux was 650 KWh/m2) at pH 7. As optimized conditions, 100 μL initial inoculum concentration of S. typhimurium was treated with 60 μg/mL of ZnO@Av NDs suspension under sunlight irradiation of 5 h, antibacterial index obtained was 6.8. The MIC and MBC for ZnO@Av NDs against S. typhimurium were 50 μL and 100 μL, respectively. It has been observed that ZnO@Av NDs lower the optical density of water that contains S. typhimurium. The photocatalytic purification of water using ZnO@Av NDs is safe and cost-effective method under sunlight irradiation, which could possibly be employed for the wastewater purification.

Gold Nanoparticles; Synthesis, Characterization and Comparative Studies of Their Antimicrobial Activities

Gold nanoparticles of various morphologies have been synthesized using different synthetic approaches. Sonochemical synthesis results in the formation of 25 nm sized gold nano discs and 30 nm sized polyhedral structures with surface area of 179.5 m2/g and 150.5 m2/g respectively[1]. The UV-Visible spectrum shows the SPR peaks due to in plane and out of plane excitation modes. Microemulsion synthesis using Tergitol NP-9 surfactant resulted in the production of hexagonal gold nanoparticles (avg. size: 20 nm) at 0.05 M HAuCl4 (aq) and spherical morphologies with an average size of 25 nm and 15 nm at molar concentrations of 0.04 M and 0.03 M HAuCl4 (aq) respectively[2]. Gold nanoparticles show the surface plasmon resonance peaks at 540 nm and 580 nm along with peaks corresponding to higher order plasmon resonance modes at shorter wavelengths. The surface area was found to increase with decrease in particle size. An ecofriendly synthetic route was also employed to synthesize gold nanoparticles using candida albicans fungal cell free extract[3]. Gold nanocrystals of 5 nm have been obtained with specific surface area of 18.9 m2/g. The encapsulation of gold nanoparticle by biomolecules of the cell free extract was confirmed by FTIR and TGA studies. Gold nanoparticle show surface plasmon resonance (SPR) peak at 540 nm. Gold nanoparticles have been tested for antimicrobial activity against fungal and bacterial species. Gold nano discs displayed higher antimicrobial action against fungus candida albicans as compared to gold polyhedral structures by inhibiting H+-ATPase activity. Biosynthesized gold nanoparticles showed good antimicrobial activity against Staphylococcus aureus and Escherichia coli. However, Escherichia coli, a gram-negative bacterium was found to be more susceptible to gold nanoparticles as compared to Staphylococcus aureus, a gram-positive bacterium. The microemulsion synthesized gold nanoparticles were tested against Candida albicans both alone and in combination with fluconazole. The gold nanoparticles in combination with fluconazole showed maximum inhibition and the antifungal activity increased with decrease in particle size.

Conformational exchange of fatty acid binding protein induced by protein-nanodisc interactions

Fatty acid binding proteins (FABPs) can facilitate the transfer of long-chain fatty acids between intracellular membranes across considerable distances. The transfer process involves fatty acids, their donor membrane and acceptor membrane, and FABPs, implying that potential protein-membrane interactions exist. Despite intensive studies on FABP-membrane interactions, the interaction mode remains elusive, and the protein-membrane association and dissociation rates are inconsistent. In this study, we used nanodiscs (NDs) as mimetic membranes to investigate FABP-membrane interactions. Our NMR experiments showed that human intestinal FABP interacts weakly with both negatively charged and neutral membranes, but it prefers the negatively charged one. Through simultaneous analysis of NMR relaxation in the rotating-frame (R1ρ), relaxation dispersion, chemical exchange saturation transfer, and dark-state exchange saturation transfer data, we estimated the affinity of the protein to negatively charged NDs, the dissociation rate, and apparent association rate. We further showed that the protein in the ND-bound state adopts a conformation different from the native structure and the second helix is very likely involved in interactions with NDs. We also found a membrane-induced FABP conformational state that exists only in the presence of NDs. This state is native-like, different from other conformational states in structure, unbound to NDs, and in dynamic equilibrium with the ND-bound state.

Effect of Morphology and Plasmonic on Au/ZnO Films for Efficient Photoelectrochemical Water Splitting.

To improve photoelectrochemical (PEC) water splitting, various ZnO nanostructures (nanorods (NRs), nanodiscs (NDs), NRs/NDs, and ZnO NRs decorated with gold nanoparticles) have been manufactured. The pure ZnO nanostructures have been synthesized using the successive ionic-layer adsorption and reaction (SILAR) combined with the chemical bath deposition (CBD) process at various deposition times. The structural, chemical composition, nanomorphological, and optical characteristics have been examined by various techniques. The SEM analysis shows that by varying the deposition time of CBD from 2 to 12 h, the morphology of ZnO nanostructures changed from NRs to NDs. All samples exhibit hexagonal phase wurtzite ZnO with polycrystalline nature and preferred orientation alongside (002). The crystallite size along (002) decreased from approximately 79 to 77 nm as deposition time increased from 2 to 12 h. The bandgap of ZnO NRs was tuned from 3.19 to 2.07 eV after optimizing the DC sputtering time of gold to 4 min. Via regulated time-dependent ZnO growth and Au sputtering time, the PEC performance of the nanostructures was optimized. Among the studied ZnO nanostructures, the highest photocurrent density (Jph) was obtained for the 2 h ZnO NRs. As compared with ZnO NRs, the Jph (7.7 mA/cm2) of 4 min Au/ZnO NRs is around 50 times greater. The maximum values of both IPCE and ABPE are 14.2% and 2.05% at 490 nm, which is closed to surface plasmon absorption for Au NPs. There are several essential approaches to improve PEC efficiency by including Au NPs into ZnO NRs, including increasing visible light absorption and minority carrier absorption, boosting photochemical stability, and accelerating electron transport from ZnO NRs to electrolyte carriers.

Plasmonic Hot Hole Extraction from CuS Nanodisks Enables Significant Acceleration of Oxygen Evolution Reactions.

Localized surface plasmon resonance (LSPR) is well known for its unique ability to tune the reactivity of plasmonic materials via photoexcitation; however, it is still an open question as to whether plasmonic holes can be directly extracted to drive valuable chemical reactions. Herein we give an affirmative answer by reporting an illumination-enhanced oxygen evolution reaction (OER) using CuS nanodisks (NDs) alone as the electrocatalyst. Impressively, under 1221 nm laser or xenon lamp illumination, an unprecedented reduction of OER overpotential was observed on the CuS ND-coated electrodes. Transient absorption combined with Mott-Schottky measurements disclosed that near-infrared (NIR) irradiation generated abundant hot holes from LSPR damping in the CuS NDs accounting for the remarkable OER performance enhancement. This is the first report on the direct utilization of plasmonic hot holes in CuS nanomaterials for boosting OER performance, opening up a new route to designing NIR-active photocatalysts/electrocatalysts by exploiting the unique LSPR properties.

Calcium-induced release of cytochrome c from cardiolipin nanodisks: Implications for apoptosis

Miniature bilayer membranes comprised of phospholipid and an apolipoprotein scaffold, termed nanodisks (ND), have been used in binding studies. When ND formulated with cardiolipin (CL), but not phosphatidylcholine, were incubated with cytochrome c, FPLC gel filtration chromatography provided evidence of a stable binding interaction. Incubation of CL ND with CaCl2 resulted in a concentration-dependent increase in sample turbidity caused by ND particle disruption. Prior incubation of CL ND with cytochrome c increased CL ND sensitivity to CaCl2-induced effects. Centrifugation of CaCl2-treated CL ND samples yielded pellet and supernatant fractions. Whereas the ND scaffold protein, apolipophorin III, was recovered in the pellet fraction along with CL, the majority of the cytochrome c pool was in the supernatant fraction. Moreover, when cytochrome c CL ND were incubated with CaCl2 at concentrations below the threshold to induce ND particle disruption, FPLC analysis showed that cytochrome c was released. Pre-incubation of CL ND with CaCl2 under conditions that do not disrupt ND particle integrity prevented cytochrome c binding to CL ND. Thus, competition between Ca2+ and cytochrome c for a common binding site on CL modulates cytochrome c binding and likely plays a role in its dissociation from CL-rich cristae membranes in response to apoptotic stimuli.

Energy Evolution, Stabilization, and Mechanotransducer Properties of Fe3O4 Vortex Nanorings and Nanodisks

Recent reports on spin structures produced in nanomaterials due to confinement of spins imposed by geometrical restrictions are at the center of rising scientific interest. Topological curling magnetic structures (vortices) exhibit unique properties, regarding the energy profile, good colloidal stability in suspensions, manipulation under a low-frequency magnetic field, and torque exertion. The last property provides the potential to mechanically eradicate cancer cells via magnetomechanical actuation using remote ac magnetic fields. Here, we study, theoretically and by micromagnetic simulations, the magnetic energy evolutions for vortex nanosystems, i.e., ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ nanodisks (NDs) and nanorings (NRs). The obtained results for magnetic energy, magnetic susceptibility, and magnetization reversal confirm that the vortex-domain structure in NRs exhibits better stability and avoids agglomeration in solution, owing to the presence of a central hole, whereas the presence of a vortex core in NDs induces magnetic remanence. Although NDs are found to exert slightly higher torques than NRs, this weakness can be compensated for by a small increase (i.e., approximately equals 20%) in the amplitude of the applied field. Our results provide evidence of the magnetic stability of the curling ground states in NRs and open the possibility of applying these systems to magnetomechanical actuation on single cells for therapeutics in biomedicine, such as cancer-cell destruction by low-frequency torque transduction.