Research On The Characteristics Of Magnetic Fluid Marbles For Drug Delivery

Liquid marbles are droplets that wrapped by a few micro/nanoparticles with hydrophobic properties,which can be regarded as a soft solid.Liquid marbles won't be wetted,which is a non-adhesion system.The contact angle of liquid marbles is close to 180 °,it is easy to move.This non-wetting property does not need to change the hydrophobicity of the contact substrate.Since the droplet does not directly contact with the substrate,and there is an air cushion between the particle layer on the surface of the droplet and the solid wall surface or water surface,the liquid marbles will remain on the solid surface or float on the water surface,and there will be no leakage during the mobile process.Liquid marbles can store trace amounts of liquid,similar to tiny containers.Several applications of liquid marbles have been reported in the literature.For example,it can be used as water pollution and gas inspector,micro reactor and so on.But recently,researchers have discovered the application prospect of liquid marbles in biomedicine.It can be used for microbial or cell culture,blood group test,drug screening and cryopreservation of mammalian cells.Magnetic field,electric field,gravity field,ultraviolet and infrared radiation can all induce the liquid marbles self-propulsion,and these external force fields can be applied to control liquid marbles.The magnetic fields does not need to be in direct contact with the liquid marbles,nor does it need to heat liquid marbles,which may affect the properties of liquid marbles.It can achieve non-contact magnetic manipulation of liquid marbles,so as to achieve directional delivery of trace liquids.In view of the characteristics of the liquid marbles,the magnetic liquid marbles is used as the drug carrier and the magnetic fields are used to manipulate it to realize the delivery of the drug.In this paper,the characteristics of the magnetic liquid marbles for drug delivery are studied.The formula for calculating the accumulation force of magnetic fluid beads under magnetic fields is solved by electromagnetic field theory.The magnetic force of magnetic fluid beads is directly proportional to volume,magnetization and magnetic field gradient.A static model of liquid marble was established to reveal the non-wetting properties of liquid marbles.The existence of surface tension makes the internal and external pressure difference of liquid marble balance with gravity,and make it can be placed on the solid or liquid surface.The relationship between the liquid marble radius,contact radius and height is analyzed,contact angle and surface tension of static liquid marbles is calculated by the flat spherical model.At the same time,liquid marbles with different volumes of different working fluids were prepared and photographed on a solid wall surface using a macro camera.Finally,relevant parameters such as its shape,contact angle and surface tension were measured.The magnetic liquid marbles are controlled by the magnetic field to move on the solid and liquid surfaces to realize the delivery of drugs.In this paper,the dynamic model of magnetic liquid marbles on solid and liquid surfaces is established respectively.The magnetic field strength,the magnetization of the magnetic liquid,and the surface tension of the magneto-elastic pinball are directly proportional to the speed.The relationship between the magnetic fields intensity,the velocity and the deformation is discussed.The velocity of the different volume of magnetic liquid marbles in the plane under different intensity and gradient magnetic fields were measured through experiments.By measuring the hysteresis contact angle and the contact radius,the correlation was obtained and the shape change during the movement was analyzed.The actual values of different magnetic fields were measured using a Gauss meter,and the numerical simulation of the magnetic fields were performed using COMSOL.The actual measured values were compared with the theoretical values.At the same time,the experiment of "climbing" of magnetic liquid marbles was implemented,the climbing speed under different permanent magnets was measured,and the relationship between the magnetic force and the gravity of the magnetic liquid marbles subjected to climbing was analyzed.From the point of view of mechanics,the floating mechanism of the liquid marbles is analyzed,the formula for the resistance of the liquid to the liquid marbles is solved,and the velocity of the magnetic liquid marble floating on the liquid surface under different magnetic fields is measured.In this paper,experiments demonstrate that magnetic field can be used for noncontact manipulating of the magnetic liquid marbles,to achieve the directional transport of drugs,which can rolling on the solid plane,slanted surface and floating on the liquid surface.It provides the corresponding theoretical and experimental basis that using magnetic liquid marble as a carrier for directional transport drugs for the future.