Search

Light-responsive biomaterials can be used for the delivery of therapeutic drugs and nucleic acids, where the tunable/precise delivery of payload highlights the potential of such biomaterials for treating a variety of conditions. The translucency of eyes and advances of laser technology in ophthalmology make light-responsive delivery of drugs feasible. Importantly, light can be applied in a non-invasive fashion; therefore, light-triggered drug delivery systems have great potential for clinical impact. This review will examine various types of light-responsive polymers and the chemistry that underpins their application as ophthalmic drug delivery systems. Graphical abstract

Melanins are a class of conjugated biopolymers with varying compositions and functions, which have a variety of potential medical and technical applications. Here, this work examines the conjugated polymers derived from a variety of phenolic monomers (catechol (CAT), levodopa (DOPA), and homogentisic acid (HGA)), using a selection of different analytical chemistry techniques to compare their properties with a view to understanding structure–function relations. The polymers display measurable conductivity, with electronic properties tuned by the functional groups pendant on the polymer backbones (which served as dopants) suggesting their potential for application in electronic devices.

Joint defects associated with a variety of etiologies often extend deep into the subchondral bone leading to functional impairment and joint immobility, and it is a very challenging task to regenerate the bone-cartilage interface offering significant opportunities for biomaterial-based interventions to improve the quality of life of patients. Herein drug-/bioactive-loaded porous tissue scaffolds incorporating nano-hydroxyapatite (nHAp), chitosan (CS) and either hydroxypropyl methylcellulose (HPMC) or Bombyx mori silk fibroin (SF) are fabricated through freeze drying method as subchondral bone substitute. A combination of spectroscopy and microscopy (Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), and X-ray fluorescence (XRF) were used to analyze the structure of the porous biomaterials. The compressive mechanical properties of these scaffolds are biomimetic of cancellous bone tissues and capable of releasing drugs/bioactives (exemplified with triamcinolone acetonide, TA, or transforming growth factor-β1, TGF-β1, respectively) over a period of days. Mouse preosteoblast MC3T3-E1 cells were observed to adhere and proliferate on the tissue scaffolds as confirmed by the cell attachment, live-dead assay and alamarBlue™ assay. Interestingly, RT-qPCR analysis showed that the TA downregulated inflammatory biomarkers and upregulated the bone-specific biomarkers, suggesting such tissue scaffolds have long-term potential for clinical application.

Carbon-based conductive and electroactive materials (e.g., derivatives of graphene, fullerenes, polypyrrole, polythiophene, polyaniline) have been studied since the 1970s for use in a broad range of applications. These materials have electrical properties comparable to those of commonly used metals, while providing other benefits such as flexibility in processing and modification with biologics (e.g., cells, biomolecules), to yield electroactive materials with biomimetic mechanical and chemical properties. In this review, we focus on the uses of these electroconductive materials in the context of the central and peripheral nervous system, specifically recent studies in the peripheral nerve, spinal cord, brain, eye, and ear. We also highlight in vivo studies and clinical trials, as well as a snapshot of emerging classes of electroconductive materials (e.g., biodegradable materials). We believe such specialized electrically conductive biomaterials will clinically impact the field of tissue regeneration in the foreseeable future. Statement of significance This review addresses the use of conductive and electroactive materials for neural tissue regeneration, which is of significant interest to a broad readership, and of particular relevance to the growing community of scientists, engineers and clinicians in academia and industry who develop novel medical devices for tissue engineering and regenerative medicine. The review covers the materials that may be employed (primarily focusing on derivatives of fullerenes, graphene and conjugated polymers) and techniques used to analyze materials composed thereof, followed by sections on the application of these materials to nervous tissues (i.e., peripheral nerve, spinal cord, brain, optical, and auditory tissues) throughout the body.

Biomaterials capable of precisely controlling the delivery of agrochemicals/biologics/drugs/fragrances have significant markets in the agriscience/healthcare industries. Here, we report the development of degradable electroactive polymers and their application for the controlled delivery of a clinically relevant drug (the anti-inflammatory dexamethasone phosphate, DMP). Electroactive copolymers composed of blocks of polycaprolactone (PCL) and naturally occurring electroactive pyrrole oligomers (e.g., bilirubin, biliverdin, and hemin) were prepared and solution-processed to produce films (optionally doped with DMP). A combination of in silico/in vitro/in vivo studies demonstrated the cytocompatibility of the polymers. The release of DMP in response to the application of an electrical stimulus was observed to be enhanced by ca. 10-30% relative to the passive release from nonstimulated samples in vitro. Such stimuli-responsive biomaterials have the potential for integration devices capable of delivering a variety of molecules for technical/medical applications.

Light-responsive biomaterials can be used for the delivery of therapeutic drugs and nucleic acids, where the tunable/precise delivery of payload highlights the potential of such biomaterials for treating a variety of conditions. The translucency of eyes and advances of laser technology in ophthalmology make light-responsive delivery of drugs feasible. Importantly, light can be applied in a non-invasive fashion; therefore, light-triggered drug delivery systems have great potential for clinical impact. This review will examine various types of light-responsive polymers and the chemistry that underpins their application as ophthalmic drug delivery systems.

For some professionally, vocationally, or technically oriented careers, curricula delivered in higher education establishments may focus on teaching material related to a single discipline. By contrast, multidisciplinary, interdisciplinary, and transdisciplinary teaching (MITT) results in improved affective and cognitive learning and critical thinking, offering learners/students the opportunity to obtain a broad general knowledge base. Chemistry is a discipline that sits at the interface of science, technology, engineering, mathematics, and medicine (STEMM) subjects (and those aligned with or informed by STEMM subjects). This article discusses the significant potential of inclusion of chemistry in MITT activities in higher education and the real-world importance in personal, organizational, national, and global contexts. It outlines the development and implementation challenges attributed to legacy higher education infrastructures (that call for creative visionary leadership with strong and supportive management and administrative functions), and curriculum design that ensures inclusivity and collaboration and is pitched and balanced appropriately. It concludes with future possibilities, notably highlighting that chemistry, as a discipline, underpins industries that have multibillion dollar turnovers and employ millions of people across the world.

Objective: Epidemiological data illustrates that there is a strong relationship between dietary intake of natural bioactive compounds and their beneficial properties against various diseases, and this stimulates academic and industrial interest in using plant-derived compounds for health and making medicines. For this reason, recent health related studies in the literature have focused on a variety of many plant-derived bioactive compounds. Even though the bioactivities of such compounds have widely been investigated, there are few studies about oligomeric species and their activities. Methods: In this review, extraction and isolation methods of the plant-derived oligomers and the use of such oligomers in health applications are summarised. Results: In the literature, many studies state that oligomeric compounds have benefits to human health. To maximize these beneficial properties, various ways to use oligomeric compounds have been examined and summarised. Conclusion: A better understanding of the specific activities of distinct components of plantderived oligomers is expected to open new avenues for drug discovery. This review gives an overview of oligomers with health beneficial properties and their possible applications in healthcare.

IntroductionThe rapid development of wearable/implantable electronic devices for biomedical applications is exciting. Telemedicine methods of personal identification and/or patient medical information directly embedded within an individual may revolutionise civilian/military healthcare, motivating the development of minimally invasive methods to print a variety of components in vivo. Potential applications include electronic devices for communications or identification, or optically-readable tags, such as barcodes and QR codes for data storage, personnel identification or medical history.MethodWe utilise a novel photochemical approach for the additive manufacture of embedded polymer components with wide-ranging biomedical applications, with the demonstrated potential for 3D printing of electronic components in vitro, ex vivo and in vivo. Custom ink formulations are applied/delivered to a substrate (material/tissue/organism) followed by photochemical development of the ink within the substrate yielding de novo designed electronic components within/on the substrate characterised by a variety of analytical methods (e.g., electrical/microscopy/spectroscopy).ResultsWe demonstrate progress towards complex electrical devices, with the fabrication of conductive polymer wires, which can form the foundation of all subsequent larger electrical devices. Subsequently, the successful printing of a functioning quick response (QR) code is demonstrated, enabling information to be embedded and easily characterised. Further measurement of this device with an optical microscope shows the ability to store information ex-vivo with a simple characterisation technique, and shows promise for effective 3D printed devices for medical applications in-vivo.ConclusionFacile printing of devices for electronic characterisation, or optical components for characterisation with a conventional camera paves the way for a next generation of embedded bioelectronics that we foresee revolutionizing healthcare via personalised telemedicine.

3D objects with integrated electronics are produced using an additive manufacturing approach relying on multiphoton fabrication (direct laser writing, (DLW)). Conducting polymer-based structures (with micrometer-millimeter scale features) are printed within exemplar matrices, including an elastomer (polydimethylsiloxane, (PDMS)) have been widely investigated for biomedical applications. The fidelity of the printing process in PDMS is assessed by optical coherence tomography, and the conducting polymer structures are demonstrated to be capable of stimulating mouse brain tissue in vitro. Furthermore, the applicability of the approach to printing structures in vivo is demonstrated in live nematodes (Caenorhabditis elegans). These results highlight the potential for such additive manufacturing approaches to produce next-generation advanced material technologies, notably integrated electronics for technical and medical applications (e.g., human-computer interfaces).

Diabetes is a group of metabolic conditions resulting in high blood sugar levels over prolonged periods that affects hundreds of millions of patients worldwide. Measuring glucose concentration enables patient-specific insulin therapy, and is essential to reduce the severity of the disease, potential complications, and related mortalities. Recent advances and developments in smartphone-based colorimetric glucose detection systems are discussed in this review. The importance of glucose monitoring, data collection, transfer, and analysis, via non-invasive/invasive methods is highlighted. The review also presents various approaches using 3D-printed materials, screen-printed electrodes, polymer templates, designs allowing multiple glucose analysis, bioanalytes and/or nanostructures for glucose detection. The positive effects of advances in improving the performance of smartphone-based platforms are introduced along with future directions and trends in the application of emerging technologies in smartphone-based diagnostics.

Multielectrode arrays (MEAs) are electrical devices that transduce (record/deliver) cellular voltage signals. Commercially available MEAs are expensive and here we provide proof of concept for the application of an additive manufacturing approach to prepare inexpensive MEAs and demonstrate their ability to interact with brain tissue ex vivo.

Melanins are a class of biopolymers that are widespread in nature, with diverse origins, compositions, and functions, and their chemical and optoelectronic properties render them potentially useful for application in materials science for various biotechnological applications. For patients with alkaptonuria, the accumulation of homogentisic acid (HGA) in their bodies is associated with the concomitant deposition of pyomelanin, which is a pigment that contains significant amounts of polymerized HGA (polyHGA) in the bodily tissues of the patients. The polymerization of HGA under various different conditions in vitro is investigated using a selection of different analytical chemistry techniques to understand if there may be a correlation between the conditions and pigment deposition in vivo, and their potential for application as green/sustainable and components of electronic devices.

Shape-memory polymers (SMPs) enable the production of stimuli-responsive polymer-based materials with the ability to undergo a large recoverable deformation upon the application of an external stimulus. Academic and industrial research interest in the shape-memory effects (SMEs) of these SMP-based materials is growing for task-specific applications. This mini-review covers interesting aspects of SMP-based materials, their properties, how they may be investigated and highlights examples of the potential applications of these materials.

Bone tissue engineering involves the combined use of materials with functional properties to regenerate bone. Nanohydroxyapatite (nHA) can influence the behavior of cells. The functional and structural properties of nHA can be controlled during nanoparticle synthesis. This review defines the relationship between the attributes of nHA nanoparticles and their biological effects, focusing on biocompatibility, surface-area-to-volume ratio, bonding chemistry, and substrate functionality. The paper explores how these aspects have been applied in the development of scaffolds for the repair of damaged bone or regeneration of missing bone.

Aligned sub-micron fibres are an outstanding surface for orienting and promoting neurite outgrowth; therefore, attractive features to include in peripheral nerve tissue scaffolds. A new generation of peripheral nerve tissue scaffolds is under development incorporating electroactive materials and electrical regimes as instructive cues in order to facilitate fully functional regeneration. Herein, electroactive fibres composed of silk fibroin (SF) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) were developed as a novel peripheral nerve tissue scaffold. Mats of SF with sub-micron fibre diameters of 190 ± 50 nm were fabricated by double layer electrospinning with thicknesses of ∼100 μm (∼70-80 μm random fibres and ∼20-30 μm aligned fibres). Electrospun SF mats were modified with interpenetrating polymer networks (IPN) of PEDOT:PSS in various ratios of PSS/EDOT (α) and the polymerisation was assessed by hard X-ray photoelectron spectroscopy (HAXPES). The mechanical properties of electrospun SF and IPNs mats were characterised in the wet state tensile and the electrical properties were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The cytotoxicity and biocompatibility of the optimal IPNs (α = 2.3 and 3.3) mats were ascertained via the growth and neurite extension of mouse neuroblastoma x rat glioma hybrid cells (NG108-15) for 7 days. The longest neurite outgrowth of 300 μm was observed in the parallel direction of fibre alignment on laminin-coated electrospun SF and IPN (α = 2.3) mats which is the material with the lowest electron transfer resistance (R

As the field of macromolecular science celebrated its 100th anniversary in 2020, we organised a special issue of Polymer International devoted to the synthesis, processing and applications of polyaryletherketones (PAEKs). Developed over 40 years ago, PAEK polymers and their composites experienced a steady increase in use and applications due to their unique characteristics: high mechanical performance, high toughness, high operating temperatures, low wear, non-flammable and chemically resistant as well as their function as a class of bioinert, robust biomaterials. The contributions to the special issue engage the materials science community and include a mixture of spotlights, perspectives, reviews, and research papers, spanning the breadth of basic science and engineering to applied technical/medical science, with authors from academic and industrial backgrounds, which reflects some of the exciting recent developments in PAEK-based materials that is of interest to a broad readership. A further area of research not particularly highlighted within this review; but very much an active concern; is the development of PAEK-based thermoplastic composites for application in the aerospace and medical sectors.

Funder: Cure Alzheimer's Fund; doi: http://dx.doi.org/10.13039/100007625, Funder: UK Dementia Research Institute (GB), Funder: Censejo Nacional de Ciencia Tecnilogia (MX), Funder: Alzheimerfonden; doi: http://dx.doi.org/10.13039/501100008599, Funder: Dolby Family Fund, Background: Microglia are active modulators of Alzheimer’s disease but their role in relation to amyloid plaques and synaptic changes due to rising amyloid beta is unclear. We add novel findings concerning these relationships and investigate which of our previously reported results from transgenic mice can be validated in knock-in mice, in which overexpression and other artefacts of transgenic technology are avoided. Methods: AppNL-F and AppNL-G-F knock-in mice expressing humanised amyloid beta with mutations in App that cause familial Alzheimer’s disease were compared to wild type mice throughout life. In vitro approaches were used to understand microglial alterations at the genetic and protein levels and synaptic function and plasticity in CA1 hippocampal neurones, each in relationship to both age and stage of amyloid beta pathology. The contribution of microglia to neuronal function was further investigated by ablating microglia with CSF1R inhibitor PLX5622. Results: Both App knock-in lines showed increased glutamate release probability prior to detection of plaques. Consistent with results in transgenic mice, this persisted throughout life in AppNL-F mice but was not evident in AppNL-G-F with sparse plaques. Unlike transgenic mice, loss of spontaneous excitatory activity only occurred at the latest stages, while no change could be detected in spontaneous inhibitory synaptic transmission or magnitude of long-term potentiation. Also, in contrast to transgenic mice, the microglial response in both App knock-in lines was delayed until a moderate plaque load developed. Surviving PLX5266-depleted microglia tended to be CD68-positive. Partial microglial ablation led to aged but not young wild type animals mimicking the increased glutamate release probability in App knock-ins and exacerbated the App knock-in phenotype. Complete ablation was less effective in altering synaptic function, while neither treatment altered plaque load. Conclusions: Increased glutamate release probability is similar across knock-in and transgenic mouse models of Alzheimer’s disease, likely reflecting acute physiological effects of soluble amyloid beta. Microglia respond later to increased amyloid beta levels by proliferating and upregulating Cd68 and Trem2. Partial depletion of microglia suggests that, in wild type mice, alteration of surviving phagocytic microglia, rather than microglial loss, drives age-dependent effects on glutamate release that become exacerbated in Alzheimer’s disease.

Electroactive hydrogels can be used to influence cell response and maturation by electrical stimulation. However, hydrogel formulations which are 3D printable, electroactive, cytocompatible, and allow cell adhesion, remain a challenge in the design of such stimuli‐responsive biomaterials for tissue engineering. Here, a combination of pyrrole with a high gelatin‐content oxidized alginate‐gelatin (ADA‐GEL) hydrogel is reported, offering 3D‐printability of hydrogel precursors to prepare cytocompatible and electrically conductive hydrogel scaffolds. By oxidation of pyrrole, electroactive polypyrrole:polystyrenesulfonate (PPy:PSS) is synthesized inside the ADA‐GEL matrix. The hydrogels are assessed regarding their electrical/mechanical properties, 3D‐printability, and cytocompatibility. It is possible to prepare open‐porous scaffolds via bioplotting which are electrically conductive and have a higher cell seeding efficiency in scaffold depth in comparison to flat 2D hydrogels, which is confirmed via multiphoton fluorescence microscopy. The formation of an interpenetrating polypyrrole matrix in the hydrogel matrix increases the conductivity and stiffness of the hydrogels, maintaining the capacity of the gels to promote cell adhesion and proliferation. The results demonstrate that a 3D‐printable ADA‐GEL can be rendered conductive (ADA‐GEL‐PPy:PSS), and that such hydrogel formulations have promise for cell therapies, in vitro cell culture, and electrical‐stimulation assisted tissue engineering.

Materials with microscale structures are gaining increasing interest due to their range of technical and medical applications. Additive manufacturing approaches to such objects via laser two-photon polymerization, also known as multiphoton fabrication, enable the creation of new materials with diverse and tunable properties. Here, we investigate the properties of 3D structures composed of organometallic polymers incorporating aluminium, titanium, vanadium and zirconium. The organometallic polymer-based materials were analysed using a variety of techniques including SEM, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy analysis and contact angle measurements and their biocompatibility was tested in vitro. Cell viability and mode of death were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and acridine orange/ethidium bromide staining. Polymers incorporating Al, Ti and Zr supported cell adhesion and proliferation, and showed low toxicity in vitro, whereas the organometallic polymer incorporating V was shown to be cytotoxic. Inductively coupled plasma optical emission spectrometry suggested that leaching of the V from the organometallic polymer is the likely cause of this. The preparation of the organometallic polymers is straightforward and both simple 2D and complex 3D structures can be fabricated with ease. Resolution tests of the newly developed organometallic polymer incorporating Al show that suspended lines with widths down to 200 nm can be fabricated. We believe that the materials described in this work show promising properties for the development of objects with sub-micron features for biomedical applications (e.g. biosensors, drug delivery devices, tissue scaffolds etc.). © 2019 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2019 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Suitable immobilisation of microorganisms and single cells is key for high-resolution topographical imaging and study of mechanical properties with atomic force microscopy (AFM) under physiologically relevant conditions. Sample preparation techniques must be able to withstand the forces exerted by the Z range-limited cantilever tip, and not negatively affect the sample surface for data acquisition. Here, we describe an inherently flexible methodology, utilising the high-resolution three-dimensional based printing technique of multiphoton polymerisation to rapidly generate bespoke arrays for cellular AFM analysis. As an example, we present data collected from live Emiliania huxleyi cells, unicellular microalgae, imaged by contact mode High-Speed Atomic Force Microscopy (HS-AFM), including one cell that was imaged continuously for over 90 min.

A novel SARS-like coronavirus (severe acute respiratory syndrome-related coronavirus-2, SARS-CoV-2) outbreak has recently become a worldwide pandemic. Researchers from various disciplinary backgrounds (social to natural science, health and medicine, etc.) have studied different aspects of the pandemic. The current situation has revealed how the ongoing development of nanotechnology and nanomedicine can accelerate the fight against the novel viruses. A comprehensive solution to this and future pandemic outbreaks includes preventing the spread of the virus through anti-viral personal protective equipment (PPE) and anti-viral surfaces, plus efforts to encourage behavior to minimize risks. Studies of previously introduced anti-viral biomaterials and their optimization to fight against SARS-CoV-2 is the foundation of most of the recent progress. The identification of non-symptomatic patients and symptomatic patients is vital. Reviewing published research highlights the pivotal roles of nanotechnology and biomaterials in the development and efficiency of detection techniques, e.g., by applying nanotechnology and nanomedicine as part of the road map in the treatment of coronavirus disease 2019 (COVID-19) patients. In this review, we discuss efforts to deploy nanotechnology, biomaterials, and stem cells in each step of the fight against SARS-CoV-2, which may provide a framework for future efforts in combating global pandemics.