Micro- and Nanotechnologies for Medicine: Emerging Frontiers and Applications

A special issue of Micromachines (ISSN 2072-666X).

Deadline for manuscript submissions: closed (15 December 2019) | Viewed by 29643

Special Issue Editors


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Guest Editor
Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, CA 90024, USA
Interests: bio-micro-electro-mechanical systems (BioMEMS); biomedical and implantable devices; biosensors; organs-on-a-chip; micro- and nanosensors for monitoring organs-on-a-chip; flexible electronics and sensors for wound healing; packaging and encapsulation of implantable devices; biomaterials; biofabrication
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Guest Editor
Department of Bioengineering, University of California – Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095, USA
Interests: biomedical engineering; bioengineering; biomaterials; tissue engineering; lab on a chip

Special Issue Information

Dear Colleagues,

This Special Issue will publish both selected papers from the 7th annual workshop on “Micro- and Nanotechnologies for Medicine: Emerging Frontiers and Applications” (8–12 July 2019, Los Angeles, CA, USA,
http://mnm.tissueeng.net/) and external contributions. Advances that have been made in micro- and nanotechnologies are expected to open up new possibilities and applications in diagnostics, therapy, drug delivery, and regenerative medicine. In this workshop, participants will acquire the fundamentals and advances in the fields of three dimensional bioprinting, bioMEMS, biomaterials, and tissue engineering. Leading experts will present the latest advances in the development of novel micro- and nanotechnologies and address a range of different challenges that are of importance to biomedicine at the interface of engineering, medicine, and biological sciences.

Prof. Mehmet Remzi Dokmeci
Dr. Samad Ahadian
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • bioprinting
  • bioMEMS
  • biomaterials
  • tissue engineering
  • microfluidics
  • medical devices
  • bionanosensors
  • nanotechnology
  • implantable devices
  • neurotechnology
  • micro and nanofabrication
  • drug delivery
  • point of care devices
  • flexible electronics

Published Papers (6 papers)

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Research

19 pages, 3824 KiB  
Article
Design and Simulation of an Integrated Centrifugal Microfluidic Device for CTCs Separation and Cell Lysis
by Rohollah Nasiri, Amir Shamloo, Javad Akbari, Peyton Tebon, Mehmet R. Dokmeci and Samad Ahadian
Micromachines 2020, 11(7), 699; https://0-doi-org.brum.beds.ac.uk/10.3390/mi11070699 - 20 Jul 2020
Cited by 44 | Viewed by 5586
Abstract
Separation of circulating tumor cells (CTCs) from blood samples and subsequent DNA extraction from these cells play a crucial role in cancer research and drug discovery. Microfluidics is a versatile technology that has been applied to create niche solutions to biomedical applications, such [...] Read more.
Separation of circulating tumor cells (CTCs) from blood samples and subsequent DNA extraction from these cells play a crucial role in cancer research and drug discovery. Microfluidics is a versatile technology that has been applied to create niche solutions to biomedical applications, such as cell separation and mixing, droplet generation, bioprinting, and organs on a chip. Centrifugal microfluidic biochips created on compact disks show great potential in processing biological samples for point of care diagnostics. This study investigates the design and numerical simulation of an integrated microfluidic device, including a cell separation unit for isolating CTCs from a blood sample and a micromixer unit for cell lysis on a rotating disk platform. For this purpose, an inertial microfluidic device was designed for the separation of target cells by using contraction–expansion microchannel arrays. Additionally, a micromixer was incorporated to mix separated target cells with the cell lysis chemical reagent to dissolve their membranes to facilitate further assays. Our numerical simulation approach was validated for both cell separation and micromixer units and corroborates existing experimental results. In the first compartment of the proposed device (cell separation unit), several simulations were performed at different angular velocities from 500 rpm to 3000 rpm to find the optimum angular velocity for maximum separation efficiency. By using the proposed inertial separation approach, CTCs, were successfully separated from white blood cells (WBCs) with high efficiency (~90%) at an angular velocity of 2000 rpm. Furthermore, a serpentine channel with rectangular obstacles was designed to achieve a highly efficient micromixer unit with high mixing quality (~98%) for isolated CTCs lysis at 2000 rpm. Full article
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12 pages, 4220 KiB  
Article
Nano-in-Micro Dual Delivery Platform for Chronic Wound Healing Applications
by Jana Zarubova, Mohammad Mahdi Hasani-Sadrabadi, Lucie Bacakova and Song Li
Micromachines 2020, 11(2), 158; https://0-doi-org.brum.beds.ac.uk/10.3390/mi11020158 - 01 Feb 2020
Cited by 9 | Viewed by 3782
Abstract
Here, we developed a combinatorial delivery platform for chronic wound healing applications. A microfluidic system was utilized to form a series of biopolymer-based microparticles with enhanced affinity to encapsulate and deliver vascular endothelial growth factor (VEGF). Presence of heparin into the structure can [...] Read more.
Here, we developed a combinatorial delivery platform for chronic wound healing applications. A microfluidic system was utilized to form a series of biopolymer-based microparticles with enhanced affinity to encapsulate and deliver vascular endothelial growth factor (VEGF). Presence of heparin into the structure can significantly increase the encapsulation efficiency up to 95% and lower the release rate of encapsulated VEGF. Our in vitro results demonstrated that sustained release of VEGF from microparticles can promote capillary network formation and sprouting of endothelial cells in 2D and 3D microenvironments. These engineered microparticles can also encapsulate antibiotic-loaded nanoparticles to offer a dual delivery system able to fight bacterial infection while promoting angiogenesis. We believe this highly tunable drug delivery platform can be used alone or in combination with other wound care products to improve the wound healing process and promote tissue regeneration. Full article
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9 pages, 2194 KiB  
Article
Energy Band Gap Investigation of Biomaterials: A Comprehensive Material Approach for Biocompatibility of Medical Electronic Devices
by Ashkan Shafiee, Elham Ghadiri, Jareer Kassis, David Williams and Anthony Atala
Micromachines 2020, 11(1), 105; https://0-doi-org.brum.beds.ac.uk/10.3390/mi11010105 - 18 Jan 2020
Cited by 15 | Viewed by 3268
Abstract
Over the past ten years, tissue engineering has witnessed significant technological and scientific advancements. Progress in both stem cell science and additive manufacturing have established new horizons in research and are poised to bring improvements in healthcare closer to reality. However, more sophisticated [...] Read more.
Over the past ten years, tissue engineering has witnessed significant technological and scientific advancements. Progress in both stem cell science and additive manufacturing have established new horizons in research and are poised to bring improvements in healthcare closer to reality. However, more sophisticated indications such as the scale-up fabrication of biological structures (e.g., human tissues and organs) still require standardization. To that end, biocompatible electronics may be helpful in the biofabrication process. Here, we report the results of our systematic exploration to seek biocompatible/degradable functional electronic materials that could be used for electronic device fabrications. We investigated the electronic properties of various biomaterials in terms of energy diagrams, and the energy band gaps of such materials were obtained using optical absorption spectroscopy. The main component of an electronic device is manufactured with semiconductor materials (i.e., Eg between 1 to 2.5 eV). Most biomaterials showed an optical absorption edge greater than 2.5 eV. For example, fibrinogen, glycerol, and gelatin showed values of 3.54, 3.02, and 3.0 eV, respectively. Meanwhile, a few materials used in the tissue engineering field were found to be semiconductors, such as the phenol red in cell culture media (1.96 eV energy band gap). The data from this research may be used to fabricate biocompatible/degradable electronic devices for medical applications. Full article
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8 pages, 1755 KiB  
Article
Methacrylate Coatings for Titanium Surfaces to Optimize Biocompatibility
by Argus Sun, Nureddin Ashammakhi and Mehmet R. Dokmeci
Micromachines 2020, 11(1), 87; https://0-doi-org.brum.beds.ac.uk/10.3390/mi11010087 - 13 Jan 2020
Cited by 4 | Viewed by 3781
Abstract
Currently, there are more than 1.5 million knee and hip replacement procedures carried out in the United States. Implants have a 10–15-year lifespan with up to 30% of revision surgeries showing complications with osteomyelitis. Titanium and titanium alloys are the favored implant materials [...] Read more.
Currently, there are more than 1.5 million knee and hip replacement procedures carried out in the United States. Implants have a 10–15-year lifespan with up to 30% of revision surgeries showing complications with osteomyelitis. Titanium and titanium alloys are the favored implant materials because they are lightweight and have high mechanical strength. However, this increased strength can be associated with decreased bone density around the implant, leading to implant loosening and failure. To avoid this, current strategies include plasma-spraying titanium surfaces and foaming titanium. Both techniques give the titanium a rough and irregular finish that improves biocompatibility. Recently, researchers have also sought to surface-conjugate proteins to titanium to induce osteointegration. Cell adhesion-promoting proteins can be conjugated to methacrylate groups and crosslinked using a variety of methods. Methacrylated proteins can be conjugated to titanium surfaces through atom transfer radical polymerization (ATRP). However, surface conjugation of proteins increases biocompatibility non-specifically to bone cells, adding to the risk of biofouling which may result in osteomyelitis that causes implant failure. In this work, we analyze the factors contributing to biofouling when coating titanium to improve biocompatibility, and design an experimental scheme to evaluate optimal coating parameters. Full article
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12 pages, 3787 KiB  
Article
Antimicrobial Activity of Silver Containing Crosslinked Poly(Acrylic Acid) Fibers
by Mohammad Mofidfar, Eun Seon Kim, Emily L. Larkin, Lisa Long, Wayne D. Jennings, Samad Ahadian, Mahmoud A. Ghannoum and Gary E. Wnek
Micromachines 2019, 10(12), 829; https://0-doi-org.brum.beds.ac.uk/10.3390/mi10120829 - 28 Nov 2019
Cited by 20 | Viewed by 3695
Abstract
Bacterial and fungal pathogens have caused serious problems to the human health. This is particularly true for untreatable infectious diseases and clinical situations where there is no reliable treatment for infected patients. To increase the antimicrobial activity of materials, we introduce silver nanoparticle [...] Read more.
Bacterial and fungal pathogens have caused serious problems to the human health. This is particularly true for untreatable infectious diseases and clinical situations where there is no reliable treatment for infected patients. To increase the antimicrobial activity of materials, we introduce silver nanoparticle (NP) patches in which the NPs are incorporated to the surface of smooth and uniform poly(acrylic acid) (PAA) nanofibers. The PAA nanofibers were thermally crosslinked with ethylene glycol via heat treatment through a mild method. The characterization of the resulting PAA-silver NP patches was done using scanning electron microscopy (SEM), UV spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). To demonstrate the antimicrobial activity of PAA, we incorporated the patches containing the silver NPs into strains of fungi such as Candida albicans (C. albican) and bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA). The PAA-silver fibers achieved zones of inhibition against C. albicans and MRSA indicating their antimicrobial activity against both fungi and bacteria. We conclude that silver NP patches exhibited multiple inhibitory actions for the interruption and blockage of activity fungal and bacterial strains, which has the potential as an antimicrobial agent in infectious diseases. Moreover, the proposed material has the potential to be used in antimicrobial textile fabrics, food packaging films, and wound dressings. Full article
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12 pages, 3892 KiB  
Article
Three-Dimensional Bioprinting of Functional Skeletal Muscle Tissue Using Gelatin Methacryloyl-Alginate Bioinks
by Rasoul Seyedmahmoud, Betül Çelebi-Saltik, Natan Barros, Rohollah Nasiri, Ethan Banton, Amir Shamloo, Nureddin Ashammakhi, Mehmet Remzi Dokmeci and Samad Ahadian
Micromachines 2019, 10(10), 679; https://0-doi-org.brum.beds.ac.uk/10.3390/mi10100679 - 09 Oct 2019
Cited by 90 | Viewed by 8288
Abstract
Skeletal muscle tissue engineering aims to fabricate tissue constructs to replace or restore diseased or injured skeletal muscle tissues in the body. Several biomaterials and microscale technologies have been used in muscle tissue engineering. However, it is still challenging to mimic the function [...] Read more.
Skeletal muscle tissue engineering aims to fabricate tissue constructs to replace or restore diseased or injured skeletal muscle tissues in the body. Several biomaterials and microscale technologies have been used in muscle tissue engineering. However, it is still challenging to mimic the function and structure of the native muscle tissues. Three-dimensional (3D) bioprinting is a powerful tool to mimic the hierarchical structure of native tissues. Here, 3D bioprinting was used to fabricate tissue constructs using gelatin methacryloyl (GelMA)-alginate bioinks. Mechanical and rheological properties of GelMA-alginate hydrogels were characterized. C2C12 myoblasts at the density 8 × 106 cells/mL were used as the cell model. The effects of alginate concentration (0, 6, and 8% (w/v)) and crosslinking mechanism (UV crosslinking or ionic crosslinking with UV crosslinking) on printability, cell viability, proliferation, and differentiation of bioinks were studied. The results showed that 10% (w/v) GelMA-8% (w/v) alginate crosslinked using UV light and 0.1 M CaCl2 provided the optimum niche to induce muscle tissue formation compared to other hydrogel compositions. Furthermore, metabolic activity of cells in GelMA bioinks was improved by addition of oxygen-generating particles to the bioinks. It is hoped that such bioprinted muscle tissues may find wide applications in drug screening and tissue regeneration. Full article
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