암 치료용 약물전달을 위한 나노바이오재료 및 융합세포

Abstract

In this contribution, various novel nanobiohybrid organisms are constructed ranging from biomaterials choice and their assembly at the biological organisms interfaces to emerging applications that are aimed at augmenting or amplifying new biological function were developed. In chapter 2, I have demonstrated a process developing Janus carrier cells coated with metal−organic frameworks (MOFs) by asymmetrically immobilizing the drug laden nanoparticles. Unlike the conventional cell-mediated drug delivery system, this new interface engineering design of the nanomaterials and biological organism allowed the biohybrids to not only better perform environment communication but also demonstrate transmigration behavior across the blood endothelial tissue. In this regard, their potential applications in cancer chemotherapy and combination therapy were verified. In addition to top-down approach to developed MOF-coated Janus cells, alternative bottom-up approach to grow exogenous MOF exoskeleton on the mammalian cells and formation of the Janus cells is performed. It is confirmed that grown MOF-exoskeleton can act as biofunctional-layer that can well-protect the cells in cytotoxic Proteinase K presenting environment while the nutrient (i.e., glucose) permeability is maintained. These results certified the potential application developed MOF-cell coating method in cell preservation or cell storage. In Chapter 3, have developed a novel active drug delivery system named biohybrid microalgae cells linked with drug laden peptide nanotubes (PNTs). The system have resolved the long persisting challenges including reduction of motility after drug conjugations, demands of complicated, time-consuming drug loading process, and requirements of the extra-system (i.e., UV-light) required for the controlled drug release at the target site. Lastly, in Chapter 4, we have proposed an expeditious straightforward synthesis method to develop biomimetic B-type carbonate apatite (CAp) with a simple capillary microfluidic device at room temperature. The process not only eliminates fluctuations with the addition of carbonate for CAp synthesis but also produces safe CAp drug carriers through simultaneous alendronate incorporation during synthesis to the CAp structure. This is to expand the opportunity for widespread clinical CAp application for enhanced bone defect treatment, particularly for bone loss and cancer to bone metastasis. CAp displayed superior cell proliferation and mineralization on osteoblast-like MG-63 cells when compared with HAp and HAp drug carriers that were produced using identical methods for comparative analysis. Furthermore, alendronate incorporated CAp drug carriers displayed higher cancer cell suppression rates when applied to breast cancer cells attached to the bone microenvironment, which verifies enhanced cancer metastasis to bone suppression due to the increased drug release rate of CAp owing to its lattice strains. Overall, our results show that biomimetic CAp can be efficiently produced and can be easily transformed into a drug carrier, with enhanced bone regeneration and cancer suppression capabilities compared to HAp. Thanks to the rapid explosion of nanotechnologies and biomaterial researches in the past decades, a material toolbox including diverse choices of organic, inorganic and hybrid materials has become possible to be exploited together with biological systems. At present, however, the full promise of nanobiohybrid constructs to real world applications has yet to be met as the field has just start to mature. Since, the field of nanobiohybrid organisms has bloomed from engineering perspectives rather than biological aspect, many questions such as the genomic level understanding of nanobiohybrid organisms are yet to be resolved. For the further improvement, it is worth to point-out that researchers in the field should not only focus on the biocompatibility aspect of nanobiohybrid organisms but also from a functional compatibility aspect such as signal transduction and communication between the materials and bio-organisms. Furthermore, in-depth understanding regarding to the interface engineering between the nanomaterials and biological organism are necessary. With more thoughtful and cooperative efforts, it is my sincere belief that nanobiohybrid organisms will not only provided insights into the field of biomedicine but also opened up new avenues for controlling cell functions with state-of-art technologies

Nanobiohybrids cells, synthesized by incorporating practical nanobiomaterials with living organisms, have developed as a sensational branch of research at the interface of biological science and nanomaterials engineering. Nanobiohybrid organisms are developed using synthetic materials to convey organisms with emergent features outside their scope of evolution. Consequently, they provide novel or amplified properties that are either natural or exogenous, such as enhanced tolerance against stress, programmed metabolism and proliferation, or artificial photosynthesis. Recent progresses in processing technologies and specialized materials design made it possible to tailor the physicochemical properties of the nanomaterials coupled with the biological systems. Up till now, various types of nanomaterials have been applied to biological systems from simple biomolecules to complex multicellular organisms. Those, nanobiohybrid organisms that enable new or augmented biological functions that show promise in high-tech applications particularly in drug delivery. Yet, specific challenges in using nanobiohybrid organisms for cancer therapy still persist. For example, cell membrane is a dynamic state and it is constantly undergoing remodeling where most of its components including lipids and membrane proteins are denatured, recycled, replaced, and internalized. The frequency of the remodeling process varies widely from hours to weeks depending on the types of lipids and proteins. Besides, the internalization of cell membrane lipids and proteins occurs routinely through endocytosis, pinocytosis and phagocytosis. Due to their size, type and property, biomaterials that are chemically conjugated, electrostatically adsorbed or hydrophobically embedded on the membrane often internalize mostly through endocytosis. The process of endocytosis often cause the toxic side effects to the carrier cells; thus, protection of cell carrier from drug toxic side effects have to be resolved. In addition, low drug loading capacity, and a premature drug release in protection of therapeutic agents against intracellular degradation and risk of blood contamination have been pointed out as the challenges of the cell mediated drug delivery system. With this regard, here, the novel facile approaches to develop various nanobiohybrid organisms applying nanotechnology and interface chemical engineering of the cell surface and nanomaterials are suggested. Furthermore, applications of developed nanobiohybrid organisms and nanobiomaterial cargos in various biomedical applications including cell protection and cancer therapy resolving some of the drawbacks current state-of-art cell mediated drug delivery systems have are demonstrated. In chapter 2, applying two different methods, Janus carrier cells coated with metal−organic frameworks (MOFs) are produced; MDA-MB-231 cells are asymmetrically immobilized with the nanoparticles of zinc based MOF, in which cytotoxic enzymes are internally encapsulated. By maintaining the biological and structural features of regular living cells, the MOF-coated Janus cells established in the study preserve the innate binding capacity of the MDA-MB-231 cells to their microenvironment. Interwoven MOFs loaded onto the other face of the Janus cells cannot internalize into the cell cytoplasm. Therefore, the carrier cells are sufficiently protected from the cytotoxic drug contained in MOFs. These MOF-Janus cells demonstrated successfully eliminate three-dimensional (3D) tumor spheroids when a chemotherapeutic protein of proteinase K is released from the MOF nanoparticles in a cancer microenvironment (at mild acidic condition). The ease with which the MOF-Janus carrier cells can be created (in 15 min), and the ability to append a variety of enzymes and even multiple ones make the developed system attractive as a universal platform for drug delivery in various applications, including combination therapy. Furthermore, an alternative approach to rapidly growing metal−organic framework (MOF) exoskeletons on a mammalian cell surface under cytocompatible conditions is proposed as a bottom-up method to develop MOF-coated Janus cells. The MOF exoskeleton layer on the mammalian cells was established via a well- known one-pot biomimetic mineralization process. With the exoskeleton on, the individual MDA-MB-231 cells were successfully protected against cytotoxic protease (i.e., Proteinase K), whereas smaller-sized nutrients (e.g., glucose) transport across the exoskeleton was maintained. Moreover, vital and genuine cellular activities mediated by transmembrane GLUT transporters were maintained witg the MOF exoskeleton on the cell surfaces. In chapter 3, a novel biohybrid microalgae system for active drug delivery to the cancer with enhanced swimming velocities and spontaneous cancer-microenvironment responsive drug release are envisioned to develop. Instead of conjugating drug-laden rigid, high density micro- or nanoparticles as a drug cargo to the microalgae cell wall, I applied more flexible, low density, small-sized peptide nanotubes (PNTs) as a drug cargo to attach onto the microalgae cell surfaces. Our biohybrid microalgae system that is developed electrostatically attaching the drug-laden PNTs revealed superior swimming velocities compared to the conventional nanoparticle adhered biohybrid microalgae cells. Furthermore, biohybrid algae cells preserved phototactic ability and directional movement towards the light was observed with the PNTs coating. Lastly, due to pH responsive nature of the PNTs, spontaneous release of encapsulated drugs from the PNTs at the cancer was observed. In addition to the nanobiohybrid cell development, in chapter 4, a novel facile approaches to develop multifunctional nanobiomaterials and their applications not only in tissue regeneration but also in cancer therapy is demonstrated. Briefly, expeditious straightforward biomaterial synthesis method is applied to develop biomimetic B-type carbonate apatite (CAp) with a simple capillary microfluidic device at room temperature. The process not only eliminates fluctuations with the addition of carbonate for CAp synthesis but also produces safe CAp drug carriers through simultaneous alendronate incorporation during synthesis to the CAp structure. This is to expand the opportunity for widespread clinical CAp application for enhanced bone defect treatment, particularly for bone loss and cancer to bone metastasis. CAp displayed superior cell proliferation and mineralization on osteoblast-like MG-63 cells when compared with HAp and HAp drug carriers that were produced using identical methods for comparative analysis. Furthermore, alendronate incorporated CAp drug carriers displayed higher cancer cell suppression rates when applied to breast cancer cells attached to the bone microenvironment, which verifies enhanced cancer metastasis to bone suppression due to the increased drug release rate of CAp owing to its lattice strains.