TA3_001. TiN-Au plasmonic NPs and beam splitting for rapid warming

Guillermo Aguilar, TAMU
Lorenzo Mangolini, UCR

Develop NP rapid heating technique to overcome devitrification and cracking after cryopreservation

Photothermal warming exploits the considerable heat generated by some nanoparticles (NP) when exposed to a highly tuned laser beam. This very fast heating technique shows promise to overcome devitrification and cracking challenges after cryopreservation.

In this project we explore Titanium Nitride (TiN) nanoparticles as they show significant advantages over the usual gold nanoparticles, such as higher heating rates, better optical properties of absorption and scattering, lower cost and higher thermal stability. Additionally, the plasmonic resonant response of TiN is in the near-infrared region, a biological window, which eliminates the need for complex structure synthesis. We have also implemented a beam splitting setup to divide the initial laser beam into four beams and thereby improve the uniformity of the thermal profile. Moreover, we have achieved a more uniform heating rate by developing TiN clusters with the Yadong Yin lab at UCR. Clusters increase the scattering cross-section of the material which leads to a better ratio between absorption and scattering required for uniform warming. Finally, we have studied the non-linear properties of TiN NPs and clusters to understand the optical tunability of these NPs solutions for photothermal warming.

As a proof of concept, after measuring the stability of the nanomaterials in CPAs, we demonstrated successful laser rewarming of a vitrified microdroplet containing TiN NPs and CPA without devitrification as well as over 95% cell viability of HDF cells when exposed to TiN NPs and clusters.

TA3_002. RF Characterization of CPA cocktails for nano-warming applications

Rhonda Franklin, UMN
Bethanie Stadler, UMN
John Bischof, UMN

Develop technique to measure temps in CPA solutions containing nanoparticles to understand the aggregate dielectric behavior of CPA mixtures

Fast and uniform rewarming can be accomplished by incorporating magnetic nanoparticles into CPA solutions used for cryopreservation and heating them with RF coils. This method is particularly promising for rewarming bulk cryopreserved systems, including organs. It may be limited by the impact of unwanted non-specific eddy current heating that could potentially lead to non-uniformities in the heating process. Understanding and predicting the potential impact of eddy current heating requires information on the dielectric behavior of the CPAs at cryogenic temperatures.

In this project, we aim to develop a standardized technique and approach for these measurements at all relevant temperatures, including cryogenic temperatures. Our efforts have focused on the fabrication and testing of a RF sensor in the GHz range to measure the resonance peak frequency shift of CPAs which correlates with the relative dielectric loss factor that is responsible for the eddy/dielectric heating inside the material. Initial results were carried out on VS55 between 0 and - 120°C and corroborate the trends reported in literature on other CPAs. We plan to extend these measurements to other common CPA components and cocktails to understand the aggregate dielectric behavior of complex mixtures, as well as extend measurements in the KHz range.

TA3_003. Development of 3D printing techniques for high-throughput cryopreservation

Michael McAlpine, UMN
John Bischof, UMN

Prepare vitrification-ready organism droplets for high-throughput cryopreservation by developing next-generation 3D printing techniques

The main project goal is to prepare vitrification-ready organism droplets for high-throughput cryopreservation by developing next-generation 3D printing techniques. To achieve this, we developed a 3D printer that can visualize living and moving organisms as well as position them with cryoprotectant droplets into cryopreservation devices within 3D spaces. The automated system was initially developed for randomly distributed single zebrafish embryos and produced survival rates of cryopreserved embryos consistent with the manual manipulation method but with nearly 12 times higher throughput. The system has been optimized to pick and place multiple shrimp embryos in < 1 μL droplets, which has increased the cryopreservation throughput by nearly 33 times compared to manual manipulation. An additional function which sorts live embryos from undesired objects has further enhanced cryopreservation throughput by 10-15% compared to cases where the integrated 3D printer assumes all embryos are suitable for cryopreservation.

TA3_004. Development of high-heating magnetic nanobars

Bethanie Stadler, UMN

Synthesis and characterization of materials whose dimensions are less than 100 nm and coating to for use in whole organ rewarming

Magnetic (induction) rewarming is a promising method to achieve rapid warming; magnetic nanoparticles generate considerable heat when exposed to an alternating magnetic field in the RF range.

This project focuses on Magnetic NanoBars in contrast to the typical spherical particles. We have simulated, synthesized and tested a variety of materials and sizes (pure Fe, Ni, or Co magnetic nanowires of 20, 50, 100, 200 nm diameter with lengths of 100nm to 3um). The hysteresis loops (magnetization versus applied field) show that the smaller the diameter of the wire, the larger the width of the loop and hence the area under the loop. A larger area is directly correlated to faster warming rates. For example with only 3mg Co/ml of VS55, the 20 nm diameter Co nanowires are predicted and measured to reach heating rates over 1000°C/min at 180kHz. Current research efforts focus on synthesis and characterization of materials whose dimensions are less than 100 nm and optimizing their coating so as to improve their suspension for use in organs.

TA3_005. Synthesis of magnetic and magnetic-plasmonic hybrid nanorods for rewarming

Yadong Yin, UCR

Establish approaches to large-scale production of magnetic, plasmonic, and hybrid nanostructures for magnetic hyperthermia and photothermal heating

This project aims to establish several promising approaches to the large-scale production of magnetic, plasmonic, and hybrid nanostructures for high-performance magnetic hyperthermia and photothermal heating.

We aim to optimize the crystallinity, size, and anisotropy of magnetic nanospheres and nanorods to produce Fe3O4 nanostructures through doping, hydrothermal synthesis and surface-protected reduction methods, achieving control over these important properties for an optimal magnetic induction heating. We propose a space-confined synthesis method to produce plasmonic nanostructures with well-controlled morphology and spatial configuration, good biocompatibility, and high stability for optimal photothermal heating performance.

We further extend the space-confined synthesis method to produce hybrid nanorods with coupled magnetic and plasmonic properties. The synergistic heating performance under laser irradiation and an alternating magnetic field will be investigated. Magnetically aligning the anisotropically shaped hybrid nanostructures will greatly enhance their heating performance.

TA3_006. Organ vitrification and nanowarming

John Bischof, UMN
Erik Finger, UMN
Michael Garwood, UMN

Vitrification and rewarming of human organs for transplant and regenerative medicine using magnetic nanoparticles in vasculature of an organ

We aim to develop approaches for successful vitrification and rewarming of human organs for long-term cryobanking for transplant and regenerative medicine applications. Ultimate project success will be achieved through reproducible vitrification, storage, rewarming, and transplant of a clinical scale organ. Our research approach focuses on demonstrating the ability to distribute magnetic nanoparticles (NP) throughout the vasculature of an organ and then activate them through an applied radiofrequency (RF) field to heat the organ rapidly and uniformly enough to avoid the ice crystallization due to inadequate warming rates and cracking induced by temperature gradients. Successful demonstration and translation of this technology in organs also requires addressing barriers in CPA toxicity, perfusion loading and unloading damage to organs and ultimately showing healthy organ function after vitrification and nanowarming. Other areas of research include advancing the technologies necessary to translate RF nanowarming to the clinical scale, such as installing RF rewarming systems sized for human organs, scaling up magnetic NP production, improving coating of the NPs and addressing off-target effects like non-specific RF heating in human-scale organs.

TA3_007. Computational tools to reduce thermal stress during cryopreservation

Yoed Rabin, CMU

Develop computation tools to explain experimental observation of damage, design cryopreservation protocols, and analyze the effect of nanowarming

Mechanical stress driven by differential thermal expansion (i.e., thermal stress) is a limiting factor on cryopreservation success in many systems and preservation protocols. When the stress exceeds the strength of the material, structural damage follows with fracture formation as its most dramatic outcome. This program focuses on developing computation tools to explain experimental observation of structural damage, to design cryopreservation protocols, and to analyze the effect of nanowarming. The computation tools allow simulation of the associated multiphysics problem, integrating concepts from the disparate fields of geometric modeling, heat transfer, fluid mechanics, solid mechanics, electromagnetism, and kinetics of crystallization. Three independent projects are being conducted in this context: 1) modeling and experimental investigation of surface deformation during vitrification, 2) thermomechanical stress during vitrification of blood vessels and 3) Modeling and experimental investigation of nanowarming applications for heart cryopreservation.

TA3_008 MPS & Tissue vitrification and rewarming

John Bischof, UMN
Erik Finger, UMN
Michael Garwood, UMN

Vitrification and rewarming of a broad range of submillimeter and millimeter scale tissue and MPS systems using a mesh substrate for the cells

Successful approaches for cryopreservation of tissues (slices, biopsies, cell clusters, etc.) and MPS will dramatically facilitate their use in regenerative medicine and biomedical research applications. We aim to develop technologies to enable Vitrification and Rewarming (VR) of a broad range of submillimeter and millimeter scale tissue and MPS systems.

In particular, the cryomesh approach for cooling and rewarming has demonstrated significant success in the cryopreservation of islets for transplant. Engineering development of the cryomesh VR concept, has focused on scale-up and improved cooling and rewarming rates, and establishing design criteria for maintaining rapid cooling and rewarming rates uniformly across mesh sizes relevant for preserving clinical batches of islets. This platform technology can facilitate effective preservation of a wide variety of other tissues and MPS.