The potential role of polymethyl methacrylate as a new packaging material for the implantable medical device in the bladder

Advances in Materials with Self-Healing Properties: A Brief Review

The development of materials with self-healing capabilities has garnered considerable attention due to their potential to enhance the durability and longevity of various engineering and structural applications. In this review, we provide an overview of recent advances in materials with self-healing properties, encompassing polymers, ceramics, metals, and composites. We outline future research directions and potential applications of self-healing materials (SHMs) in diverse fields. This review aims to provide insights into the current state-of-the-art in SHM research and guide future efforts towards the development of innovative and sustainable materials with enhanced self-repair capabilities. Each material type showcases unique self-repair mechanisms tailored to address specific challenges. Furthermore, this review investigates crack healing processes, shedding light on the latest developments in this critical aspect of self-healing materials. Through an extensive exploration of these topics, this review aims to provide a comprehensive understanding of the current landscape and future directions in self-healing materials research.

Pyrroloquinoline Based Styryl Dyes Doped PMMA, PS, and PS/TiO2 Polymer for Fluorescent Applications

This article presents two highly fluorescent donor-π-acceptor (D-π-A) moieties containing an electron-donating carbazole and phenothiazine donors fused with electron-withdrawing pyrrolo-quinoline acceptor dyes, PQC and PQPT. We also discussed the polymerization and film-forming process of dye PQC and PQPT doped in poly (methyl methacrylate) (PMMA) and polystyrene (PS) polymer to find their optical applications in polymer-based technology. We investigated the fluorescent properties of dyes PQC and PQPT from 0.01 to 1 wt% in poly(methyl methacrylate) (PMMA). We also investigated the changes in the spectrum shape and shift in wavelength with changes in poly(methyl methacrylate) (PMMA), polystyrene (PS), and TiO₂ doped in polystyrene (PS/TiO₂). The analysis of surface morphology of prepared polymer samples was done with the help of a scanning electron microscope. The thermal and photostability of synthesized dyes in poly (methyl methacrylate) (PMMA), polystyrene (PS), and TiO₂ doped in polystyrene (PS/TiO₂) were investigated to get detailed information owing to the application of fluorescent polymers in the field of optoelectronic, nanohybrid coatings in solar concentrators, etc.

Recent Developments in Blood-Compatible Superhydrophobic Surfaces

Superhydrophobic surfaces, as indicated in the name, are highly hydrophobic and readily repel water. With contact angles greater than 150° and sliding angles less than 10°, water droplets flow easily and hardly wet these surfaces. Superhydrophobic materials and coatings have been drawing increasing attention in medical fields, especially on account of their promising applications in blood-contacting devices. Superhydrophobicity controls the interactions of cells with the surfaces and facilitates the flowing of blood or plasma without damaging blood cells. The antibiofouling effect of superhydrophobic surfaces resists adhesion of organic substances, including blood components and microorganisms. These attributes are critical to medical applications such as filter membranes, prosthetic heart valves, extracorporeal circuit tubing, and indwelling catheters. Researchers have developed various methods to fabricate blood-compatible or biocompatible superhydrophobic surfaces using different materials. In addition to being hydrophobic, these surfaces can also be antihemolytic, antithrombotic, antibacterial, and antibiofouling, making them ideal for clinical applications. In this review, the authors summarize recent developments of blood-compatible superhydrophobic surfaces, with a focus on methods and materials. The expectation of this review is that it will support the biomedical research field by providing current trends as well as future directions.

Acrylate and Methacrylate Polymers' Applications: Second Life with Inexpensive and Sustainable Recycling Approaches

Polymers are widely employed in several fields thanks to their wide versatility and the easy derivatization routes. However, a wide range of commercial polymers suffer from limited use on a large scale due to their inert nature. Nowadays, acrylate and methacrylate polymers, which are respectively derivatives of acrylic or methacrylic acid, are among the most proposed materials for their useful characteristics like good biocompatibility, capping ability toward metal clusters, low price, potentially recyclability and reusability. Here, we discuss the advantages and challenges of this class of smart polymers focusing our attention on their current technological applications in medical, electronic, food packaging and environmental remediation fields. Furthermore, we deal with the main issue of their recyclability, considering that the current commercial bioplastics are not yet able to meet the global needs as much as to totally replace fossil-fuel-based products. Finally, the most accredited strategies to reach recyclable composites based on acrylic polymers are described.

Mixed Mode Crack Propagation in Polymers Using a Discrete Lattice Method

The fracture behavior of polymeric materials has been widely studied in recent years, both experimentally and numerically. Different numerical approaches have been considered in the study of crack propagation processes, from continuum-based numerical formulations to discrete models, many of the latter being limited in the selection of the Poisson's coefficient of the considered material. In this work, we present a numerical and experimental analysis of the crack propagation process of polymethylmethacrylate beams with central and eccentric notches subjected to quasi-static three-point bending tests. The developed discrete numerical model consists of a regular triangular lattice model based on axial and normal interaction springs, accounting for nearest-neighbor interactions. The proposed model allows solving the above mentioned limitation in the selection of Poisson's coefficient, incorporating a fracture criterion defined by a bilinear law with softening that includes the fracture energy in the formulation and allows considering a progressive damage. One of the main objectives of this work is to show the capacity of this lattice to simulate quasi-static fracture problems. The obtained results show that the proposed lattice model is capable of providing results close to the experimental ones in terms of crack pattern, peak load and initial stiffening.

Surface Enhanced Raman Spectroscopy Based Biosensor with a Microneedle Array for Minimally Invasive In Vivo Glucose Measurements

To monitor blood glucose levels reliably, diabetic patients usually have to undergo frequent fingerstick tests to draw out fresh blood, which is painful and inconvenient with the potential risk of cross contamination especially when the lancet is reused or not properly sterilized. This work reports a novel surface-enhanced Raman spectroscopy (SERS) sensor for the in situ intradermal detection of glucose based on a low-cost poly(methyl methacrylate) microneedle (PMMA MN) array. After incorporating 1-decanethiol (1-DT) onto the silver-coated array surface, the sensor was calibrated in the range of 0-20 mM in skin phantoms then tested for the in vivo quantification of glucose in a mouse model of streptozocin (STZ)-induced type I diabetes. The results showed that the functional poly(methyl methacrylate) microneedle (F-PMMA MN) array was able to directly measure glucose in the interstitial fluid (ISF) in a few minutes and retain its structural integrity without swelling. The Clarke error grid analysis of measured data indicated that 93% of the data points lie in zones A and B. Moreover, the MN array exhibited minimal invasiveness to the skin as the skin recovered well without any noticeable adverse reaction in 10 min after measurements. With further improvement and proper validation, this polymeric MN array-based SERS biosensor has the potential to be used in painless glucose monitoring of diabetic patients in the future.

A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants

To date, a wide variety of neural tissue implants have been developed for neurophysiology recording from living tissues. An ideal neural implant should minimize the damage to the tissue and perform reliably and accurately for long periods of time. Therefore, the materials utilized to fabricate the neural recording implants become a critical factor. The materials of these devices could be classified into two broad categories: electrode materials as well as packaging and substrate materials. In this review, inorganic (metals and semiconductors), organic (conducting polymers), and carbon-based (graphene and carbon nanostructures) electrode materials are reviewed individually in terms of various neural recording devices that are reported in recent years. Properties of these materials, including electrical properties, mechanical properties, stability, biodegradability/bioresorbability, biocompatibility, and optical properties, and their critical importance to neural recording quality and device capabilities, are discussed. For the packaging and substrate materials, different material properties are desired for the chronic implantation of devices in the complex environment of the body, such as biocompatibility and moisture and gas hermeticity. This review summarizes common solid and soft packaging materials used in a variety of neural interface electrode designs, as well as their packaging performances. Besides, several biopolymers typically applied over the electrode package to reinforce the mechanical rigidity of devices during insertion, or to reduce the immune response and inflammation at the device-tissue interfaces are highlighted. Finally, a benchmark analysis of the discussed materials and an outlook of the future research trends are concluded.

Robust Thin Film Surface with a Selective Antibacterial Property Enabled via a Cross-Linked Ionic Polymer Coating for Infection-Resistant Medical Applications

Fabrication of new antibacterial surfaces has become a primary strategy for preventing device-associated infections (DAIs). Although considerable progress has recently been made in reducing DAIs, current antibacterial coating methods are technically complex and do not allow selective bacterial killing. Here, we propose novel anti-infective surfaces made of a cross-linked ionic polymer film that achieve selective bacteria killing while simultaneously favoring the survival of mammalian cells. A one-step polymerization process known as initiated chemical vapor deposition was used to generate a cross-linked ionic polymer film from 4-vinylbenzyl chloride and 2-(dimethylamino) ethyl methacrylate monomers in the vapor phase. In particular, the deposition process produced a polymer network with quaternary ammonium cross-linking sites, which provided the surface with an ionic moiety with an excellent antibacterial contact-killing property. This method confers substrate compatibility, which enables various materials to be coated with ionic polymer films for use in medical implants. Moreover, the ionic polymer-deposited surfaces supported the healthy growth of mammalian cells while selectively inhibiting bacterial growth in coculture models without any detectable cytotoxicity. Thus, the cross-linked ionic polymer-based antibacterial surface developed in this study can serve as an ideal platform for biomedical applications that require a highly sterile environment.

Permeability of Novel Chitosan-g-Poly(Methyl Methacrylate) Amphiphilic Nanoparticles in a Model of Small Intestine In Vitro

Engineering of drug nanocarriers combining fine-tuned mucoadhesive/mucopenetrating properties is currently being investigated to ensure more efficient mucosal drug delivery. Aiming to improve the transmucosal delivery of hydrophobic drugs, we designed a novel nanogel produced by the self-assembly of amphiphilic chitosan graft copolymers ionotropically crosslinked with sodium tripolyphosphate. In this work, we synthesized, for the first time, chitosan-g-poly(methyl methacrylate) nanoparticles thiolated by the conjugation of N-acetyl cysteine. First, we confirmed that both non-crosslinked and crosslinked nanoparticles in the 0.05⁻0.1% w/v concentration range display very good cell compatibility in two cell lines that are relevant to oral delivery, Caco-2 cells that mimic the intestinal epithelium and HT29-MTX cells that are a model of mucin-producing goblet cells. Then, we evaluated the effect of crosslinking, nanoparticle concentration, and thiolation on the permeability in vitro utilizing monolayers of (i) Caco-2 and (ii) Caco-2:HT29-MTX cells (9:1 cell number ratio). Results confirmed that the ability of the nanoparticles to cross Caco-2 monolayer was affected by the crosslinking. In addition, thiolated nanoparticles interact more strongly with mucin, resulting in a decrease of the apparent permeability coefficient (Papp) compared to the pristine nanoparticles. Moreover, for all the nanoparticles, higher concentration resulted in lower Papp, suggesting that the transport pathways can undergo saturation.

Surface Modification of Poly(dimethylsiloxane) with Polydopamine and Hyaluronic Acid To Enhance Hemocompatibility for Potential Applications in Medical Implants or Devices

Poly(dimethylsiloxane) (PDMS) has been widely utilized in micro-electromechanical systems (MEMS) and implantable devices. To improve the hemocompatibility of a PDMS-based implant, a facile technique was developed by modifying PDMS with a hyaluronic acid (HA) and polydopamine (PDA) composite (HA/PDA). Under appropriate ratio of HA to PDA, platelet adhesion and activation were considerably reduced on modified PDMS substrates, indicating an enhanced hemocompatibility compared to native PDMS or those coated with HA or PDA solely. HA/PDA coating also posed minimal cytotoxicity on the adhesion and proliferation of endothelial cells (HUVECs). The anti-inflammation effect of the modified PDMS surface was characterized based on the expression of critical cytokines in adherent macrophages. This study revealed that the hemocompatibility, cytotoxicity, and anti-inflammation properties could be tailored conveniently by adjusting the ratio of HA and PDA composite on the modified PDMS surface, which has an exceptional potential as the core or packaging material for constructing implantable devices in biomedical applications.

Subcutaneous Photovoltaic Infrared Energy Harvesting for Bio-Implantable Devices

Wireless biomedical implantable devices on the mm-scale enable a wide range of applications for human health, safety, and identification, though energy harvesting and power generation are still looming challenges that impede their widespread application. Energy scavenging approaches to power biomedical implants have included thermal [1-3], kinetic [4-6], radio-frequency [7-11] and radiative sources [12-14]. However, the achievement of efficient energy scavenging for biomedical implants at the mm-scale has been elusive. Here we show that photovoltaic cells at the mm-scale can achieve a power conversion efficiency of more than 17 % for silicon and 31 % for GaAs under 1.06 μW/mm2 infrared irradiation at 850 nm. Finally, these photovoltaic cells demonstrate highly efficient energy harvesting through biological tissue from ambient sunlight, or irradiation from infrared sources such as used in present-day surveillance systems, by utilizing the near infrared (NIR) transparency window between the 650 nm and 950 nm wavelength range [15-17].

RP-HPLC detection and dosage method for acrylic monomers and degradation products released from implanted medical devices

Acrylic copolymers are useful in medical therapeutics. As in dental implants or intraocular lenses, acrylics are present in many medical devices or drug adjuvants. Industrial using of acrylics is still important in painting or textile manufacturing. Scientific research background has proved that acrylic suffer for depolymerized and cross-linking mechanisms under heating and photo-oxidative conditions. Those aging processes could lead to release of unreacted monomers and degradation products. We developed a new RP-HPLC method with good resolution, recovery, linearity, detection and quantification limits that is efficient for acrylic monomers quantification in in vitro and in vivo saline solution matrices. This method allows the detection of copolymer and medical devices degradation products too. Both the limit of quantification and the limit of detection for monomers and degradation products are above cytotoxic concentrations for human epithelial cells. Those biological results confirm the interest of the method for dosage of unreacted acrylics after polymerization and for the research of degradation products in body fluids as aqueous humor.