Tissue Engineering and Nanotheranostics

The following sections are included:

• Preface
• Contents

Engineered skeletal muscle grafts have made great progress during the past decades, benefiting from a growing understanding of mechanobiology and stem cell differentiation. Current techniques are widely varied, ranging from in vitro methods following the classical tissue engineering paradigm to in situ approaches such as host cell recruitment. In different ways, all of these try to supply mechanical toughness while providing the necessary signals for differentiation and maturation of the engineered skeletal muscle.

Fetal research has a considerable impact on the life of a child and his family, making it extremely critical for the scientific community. Biomaterial implants used in hernia repair and aortic arch reconstruction are also employed for open fetal surgery and fetoscopic applications. The internal environment around the fetus is drastically different compared to an abdominal or cardiac setting, and needs to be studied further with regards to the pH changes, mechanical impact during fetal growth, and degradation profiles. These studies will in-turn affect the desired properties of polymeric implants used in fetal surgery, and also the characterizations to be performed. What we learn from them will not only help us understand the property requirements of the implants, but also aid in realizing the relationship between the fetal tissues and the implants. This chapter reviews the range of characterizations carried out on polymeric implants used in abdominal and cardiac applications, which need to be applied for fetal implants for a more confident approach towards fetal surgery.

Articular cartilage is hyaline cartilage which has very limited self-repairingcapacity after its degeneration or injury. Recently, three-dimensional (3D) bioprinting provides a promising method for repair and regeneration of articular cartilage. Significant progress has been made in 3D bioprinting for cartilage regeneration, particularly in printing hydrogels in combination of cells and growth factors. In this chapter, we reviewed recent progress in cartilage 3D bioprinting, including the use of various cell sources and growth factors for cartilage formation. We also discussed the challenges and the future research directions of cartilage regeneration.

Human pluripotent stem cells (hPSCs), including human embryonic stem cells and induced pluripotent stem cells, are a potentially inexhaustible supply of human cells because they can be propagated indefinitely while still retaining the capacity to differentiate into all somatic cell types. Hurdles facing utilization of hPSCs in regenerative medicine include lack of reliable and efficient methods to differentiate hPSCs into disease related cell lineages, including neurons, cardiac muscle cells and pancreatic beta cells. During differentiation, hPSCs make a number of developmental decisions to generate first the three germ layers (ectoderm, mesoderm and endoderm), followed by subsequent decisions to generate all of the body’s mature tissues. These differentiation processes often involve a limited set of developmental cell signaling pathways, which can be modulated by growth factors and small molecules. Therefore, common methods of differentiating hPSCs to therapeutic applicable cell lineages require application of specific combination of growth factors and/or small molecules at distinct differentiation stages. This chapter discusses recent progress in the production of therapeutically applicable cells via directed differentiation of hPSCs.

Cancer, unrestrained development of abnormal cells in the body, is a serious threatening disease which has been defeating many important lives every year. The tumor, a mass of tissues, the clotting of abnormal cells, starts when old cells do not die and grow in as uncontrollable manner. Proper diagnosis at early stage can increase the survival rate. Therefore, scientists and medical experts are focusing their efforts on early detection of premature tumor and proper treatment to improve the life of cancer patients. Nanotechnology has been applied extensively in the field of cancer research, particularly, nanotheranostics for the advancement of effective approaches for diagnosis and treatment. Magnetic nanohybrid particles, combining non-invasive molecular imaging probe with therapeutic particles, have been contributing significantly towards magnetic resonance imaging (MRI) and phototherapy for cancers. Magnetic nanoparticles are successfully applied as MRI contrast agents and excited photosynthesizers are able to produce cytotoxic reactive oxygen species, such as singlet oxygen (¹O₂) which can oxidize cellular macromolecules leading to tumor cell ablation. In this chapter, we provide various aspects of magnetic nanohybrid particles, specifically, recent developments in the fabrication of complex hybrid structures, applications of tumor-targeted MRI, photodynamic/photothermal therapy and the outstanding challenges to these approaches.

Plasmonic nanoparticles hold great promising potential in applications for biosensor and bioimaging due to their unique optical property, tunable physical morphology, and surface characteristics. They extinct incident light with a certain wavelength efficiency, caused by coherent oscillation of the conduction electrons on their surface at nanoscale, and their strong interaction is known as localized surface plasmon resonance (LSPR). Meanwhile, their LSPR spectral, highly associated with their size, shape, and microenvironment surrounding them, provide us a conventional way to investigate the biomolecules’ interaction, such as cell protein expression and DNA hybridization, and map the LSPR probe at the single molecule level. Additionally, plasmonic nanoparticle-based energy transfer, surfaceenhanced Raman scattering, and photothermal therapy further enlarge its application in analyzing biomolecule and killing tumor in vivo.

In this chapter, we present a new nanoparticle methodology for treating cancerous tumors. The methodology is based upon a characteristic of cancer cells: that is, cells with an excess of centrioles. Centrioles are small cylindrical organelles lying adjacent to the nucleus. They create the electromagnetic field in a cell. But with an excess of centrioles, the electromagnetic field is enhanced. This enhancement then provides a biomarker for magnetically charged toxic nanoparticles. The chapter provides a basis for these assertions.

Nanomaterials with different morphologies and functions have been widely developed. Among them, the nanotheranostic systems designed and simultaneously used for therapeutics and diagnostics draw particular attention. To achieve the multifunctionality in one nanoformulation, typically four components are included: nanocarriers, targeting ligand, imaging domain and therapeutics. This review is aimed at introducing some examples of possibilities for the different components in a nanotheranostic system.

The following section is included:

• Index