Pouria Fattahi

A Review of Organic and Inorganic Biomaterials for Neural Interfaces

Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided fi rst, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.

Polymeric nanoparticles: the future of nanomedicine

Polymeric nanoparticles (NPs) are one of the most studied organic strategies for nanomedicine. Intense interest lies in the potential of polymeric NPs to revolutionize modern medicine. To determine the ideal nanosystem for more effective and distinctly targeted delivery of therapeutic applications, particle size, morphology, material choice, and processing techniques are all research areas of interest. Utilizations of polymeric NPs include drug delivery techniques such as conjugation and entrapment of drugs, prodrugs, stimuli-responsive systems, imaging modalities, and theranostics. Cancer, neurodegenerative disorders, and cardiovascular diseases are fields impacted by NP technologies that push scientific boundaries to the leading edge of transformative advances for nanomedicine.

A high performance hybrid asymmetric supercapacitor via nano-scale morphology control of graphene, conducting polymer, and carbon nanotube electrodes

An asymmetric supercapacitor, exploiting ultra-high density aligned activated graphene flakes as the positive electrode and nm-scale conformal coating of a conducting polymer poly(ethylenedioxythiophene) on aligned carbon nanotubes as the negative electrode, is introduced. By complementary tailoring of the asymmetric electrodes, the layered device exhibits a wide 4 V electrochemical window, with the highest power density (149 kW L−1) and energy density (113 Wh L−1) reported thus far for carbon-based supercapacitors.

Microencapsulation of Chemotherapeutics into Monodisperse and Tunable Biodegradable Polymers via Electrified Liquid Jets: Control of Size, Shape, and Drug Release

This paper describes microencapsulation of antitumor agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, Carmustine) into biodegradable polymer poly(lactic-co-glycolic) acid (PLGA) using an electrojetting technique. The resulting BCNU-loaded PLGA microcapsules have significantly higher drug encapsulation efficiency, more tunable drug loading capacity, and (3) narrower size distribution than those generated using other encapsulation methods.

3D Near‐Field Electrospinning of Biomaterial Microfibers with Potential for Blended Microfiber‐Cell‐Loaded Gel Composite Structures

This paper describes the development of a novel low-cost and efficient method, 3D near-field electrospinning, to fabricate high-resolution, and repeatable 3D polymeric fiber patterns on nonconductive materials with potential use in tissue engineering. This technology is based on readily available hobbyist grade 3D printers. The result is exquisite control of the deposition of single fibers in an automated manner. Additionally, the fabrication of various fiber patterns, which are subsequently translated to unique cellular patterns, is demonstrated. Finally, poly(methyl methacrylate) fibers are printed within 3D collagen gels loaded with cells to introduce anisotropic properties of polymeric fibers within the cell-loaded gels.

Characterization of the size, shape, and drug encapsulation efficiency of PLGA microcapsules produced via electrojetting for drug delivery to brain tumors

Despite significant progress in the development of new chemotherapeutic agents and drug delivery methods for brain tumors, malignant gliomas (high grade brain tumor) remains deadly with a median one-year survival time. A major unmet challenge in the treatment of malignant gliomas is the development of effective and targeted local delivery of chemotherapeutic agents at the cellular level. Here, we report the results of a systematic study of the size, shape, and drug release profiles of Poly(lactic-co glycolic) (PLGA) microcapsules produced and loaded with the anticancer agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) using an electrojetting technique. We quantify the shape and size distribution of BCNU-loaded PLGA microcapsules as a function of the polymer concentration and flow rate used during electrojetting, and measure drug release profiles for microcapsules of three different morphologies: flattened microspheres, microspheres, and microfibers. The BCNU release profiles for three microcapsule morphologies are found to be in good agreement with model predictions for drug release as a result of drug diffusion and degradation of PLGA.

Bio-Instructive Scaffolds for Musculoskeletal Interfaces

Tissue interfaces are integral to the function of many tissues and for the synchronous interaction amongst tissues to create a functional whole organism. From a tissue engineering perspective, the interface presents a unique challenge compared to designing a scaffold to replace or repair bulk tissue. It is at the interface that one tissue ends and another begins and where the forces and biochemistry must be correctly transferred so that the connected tissues coordinate to function as a whole. Tissue interfaces are critical to ultimately fulfill the mechanical, physical, and biochemical responses necessary within the body. This chapter will cover the following musculoskeletal interfaces: muscle:tendon (myotendinous), motor neuron:muscle fiber (neuromuscular junctions), cartilage:bone (osteochondral), bone:tendon (osteotendinous), and bone:ligament (osteoligamentous). Key parameters for these musculoskeletal interfaces, such as relevant design rationales, the structure–function relationships, and the formation and maintenance of multitissue systems, will be reviewed and discussed.