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Publications
Open Access to all SM3 publications
Over the past few years, SM3 researchers have published articles in various journals and across many different fields. Our publications showcase the cross-disciplinary research we conduct, highlighting our commitment to advancing knowledge and innovation.
Climate change due to the greenhouse effect poses arguably the greatest challenge to humanity. Addressing the sources of CO2 and reducing current atmospheric levels is the paramount task for scientists and engineers. Carbon capture with storage or utilization technologies are key to achieving this goal. Biological carbon fixation is an effective method of converting pollutant CO2 into usable biochemicals for industrial applications. Inspired by recent evidence that 95 % of CO2 from aerosol emissions from an Australian forest fire was captured by algae in the Southern Ocean, as well as the ability of algae to be transported within aerosols, we propose a novel technique for CO2 sequestration based on creating aerosols containing metabolically active cyanobacteria. Using aerosols as a microenvironment for Synechocystis cells enables a significant increase in gas-liquid-interfacialsurface-area while reducing the volume of water required. We utilize electron microscopy and hyperspectral microscopy to assess the effects of aerosolization and high CO2 concentrations on microbial cell viability. Additionally, we implemented highspeed imaging and oil immersion microscopy to determine the effectiveness of the aerosolization technique for forming aerosols and optimizing process parameters. We show that 1 % CO2 (v/v) is ideal for CO2 capture, where cell stress was minimized. Using cell densities of 1.2 × 108 cell/mL was the most efficient in terms of the number of cells aerosolized when compared to the input cell density. We report a 6- fold increase in carbon fixation rates (gCO2 g− 1 biomass hr− 1 ) over alternative popular cultivation techniques such as bubble columns.
The failure of polypropylene mesh is marked by significant side effects and debilitation, arising from a complex interplay of factors. One key contributor is the pronounced physico-mechanical mismatch between the polypropylene (PP) fibres and surrounding tissues, resulting in substantial physical damage, inflammation, and persistent pain. However, the primary cause of sustained inflammation due to polypropylene itself remains incompletely understood. This study comprises a comprehensive, multi-pronged investigation to unravel the effects of implantation on a presumed inert PP mesh in sheep. Employing both advanced and conventional techniques to discern the physical and chemical transformations of the implanted PP. Our analyses reveal a surface degradation and oxidation of polypropylene fibres after 60 days implantation, persisting and intensifying at the 180-day mark. The emergence and accumulation of PP debris in the tissue surrounding the implant also increased with implantation time. We demonstrate observable physical and mechanical alterations in the fibre surface and stiffness. Our study shows surface alterations which indicate that PP is evidently less chemically inert than was initially presumed. These findings underscore the need for a re-evaluation of the biocompatibility and long-term consequences of using PP mesh implants.
Palladium films hold signicance due to their remarkable affinity for hydrogen diffusion, rendering them valauble for the seperation and purification of hydrogen in membrane reactors. However, palladium is expensive, and its films can become brittle after only a few cycles of hydrogen separation. Alloying with silver has been shown to overcome the problem of palladium embrittlement. Palladium-silver films have been produced via several methods but all have drawbacks, such as difficulties controlling the alloy composition. This study explores two promising jet printing methods: Inkjet and Aerosoljet. Both methods offer potential advantages such as direct patterning, which reduces waste, enables thin film production, and allows for the control of alloy composition. For the first time, palladium-silver alloys have been produced via inkjet printing using a palladium-silver metal organic decomposition (MOD) ink, which alloys at a temperature of 300 °C with nitrogen. Similarly, this study also demonstrates a pioneering approach for Aerosol Jet printing, showing the potential of a novel room-temperature method, for the deposition of palladium-silver MOD inks. This low temperature approach is considered an important development as palladium-silver MOD inks are originally designed for deposition on heated substrates.
Biologically derived hierarchical structural materials not only boast energyefficient processing but also exhibit impressive mechanical performance. Silk stands as the gold standard in hierarchical fiber production, leveraging a unique combination of advantages. Nevertheless, the artificial replication of silk poses technical challenges related to precision processing and comprehensive molecular control. To address such issues, this study investigates the hierarchical assembly of solid regenerated silk in an air atmosphere, facilitated by the incorporation of carbon nanotube (CNT) seeding. Results obtained highlight that this CNT seeding facilitates multiscale structure development in response to post-spin tensile stress. Such CNT bridged structure assembly bypasses some natural processing control variables (pH, ions) and the necessary solvent immersed state for conventional silk post-drawing. Combining secondary electron hyperspectral imaging and 3D synchrotron X-ray ptychotomography, this study reports silk protein conversion from a disordered as-spun state to a longitudinal orientated semi-crystalline nano structure during drawing. The development of microscale structure during the drawing process is attributed to the presence of CNTs, yielding mechanical properties comparable to, and frequently surpassing, those exhibited by native fibers. These findings collectively propose a framework for exploring novel processing routes and offer a practical means controlling self-assembly in silk materials.
Assessing the Quality of Oxygen Plasma Focused Ion Beam (O-PFIB) Etching on Polypropylene Surfaces Using Secondary Electron Hyperspectral Imaging. (2023, Polymers)
The development of Focused Ion Beam–Scanning Electron Microscopy (FIB-SEM) systems has provided significant advances in the processing and characterization of polymers. A fundamental understanding of ion–sample interactions is still missing despite FIB-SEM being routinely applied in microstructural analyses of polymers. This study applies Secondary Electron Hyperspectral Imaging to reveal oxygen and xenon plasma FIB interactions on the surface of a polymer (in this instance, polypropylene). Secondary Electron Hyperspectral Imaging (SEHI) is a technique housed within the SEM chamber that exhibits multiscale surface sensitivity with a high spatial resolution and the ability to identify carbon bonding present using low beam energies without requiring an Ultra High Vacuum (UHV). SEHI is made possible through the use of through-the-lens detectors (TLDs) to provide a low-pass SE collection of low primary electron beam energies and currents. SE images acquired over the same region of interest from different energy ranges are plotted to produce an SE spectrum. The data provided in this study provide evidence of SEHI’s ability to be a valuable tool in the characterization of polymer surfaces post-PFIB etching, allowing for insights into both tailoring polymer processing FIB parameters and SEHI’s ability to be used to monitor serial FIB polymer surfaces in situ.
Chemical imaging (CI) is the spatial identification of molecular chemical composition and is critical to characterising the (in-) homogeneity of functional material surfaces. Nanoscale CI on bulk functional material surfaces is a longstanding challenge in materials science and is addressed here.
We demonstrate the feasibility of surface sensitive CI in the scanning electron microscope (SEM) using colour enriched secondary electron hyperspectral imaging (CSEHI). CSEHI is a new concept in the SEM, where secondary electron emissions in up to three energy ranges are assigned to RGB (red, green, blue) image colour channels. The energy ranges are applied to a hyperspectral image volume which is collected in as little as 50 s. The energy ranges can be defined manually or automatically.
Manual application requires additional information from the user as first explained and demonstrated for a lithium metal anode (LMA) material, followed by manual CSEHI for a range of materials from art history to zoology.
We introduce automated CSEHI, eliminating the need for additional user information, by finding energy ranges using a non-negative matrix factorization (NNMF) based method. Automated CSEHI is evaluated threefold: (1) benchmarking to manual CSEHI on LMA; (2) tracking controlled changes to LMA surfaces; (3) comparing automated CSEHI and manual CI results published in the past to reveal nanostructures in peacock feather and spider silk. Based on the evaluation, CSEHI is well placed to differentiate/track several lithium compounds formed through a solution reaction mechanism on a LMA surface (eg. lithium carbonate, lithium hydroxide and lithium nitride). CSEHI was used to provide insights into the surface chemical distribution on the surface of samples from art history (mineral phases) to zoology (di-sulphide bridge localisation) that are hidden from existing surface analysis techniques. Hence, the CSEHI approach has the potential to impact the way materials are analysed for scientific and industrial purposes.
Palladium films hold signicance due to their remarkable affinity for hydrogen diffusion, rendering them valauble for the seperation and purification of hydrogen in membrane reactors. However, palladium is expensive, and its films can become brittle after only a few cycles of hydrogen separation. Alloying with silver has been shown to overcome the problem of palladium embrittlement. Palladium-silver films have been produced via several methods but all have drawbacks, such as difficulties controlling the alloy composition. This study explores two promising jet printing methods: Inkjet and Aerosoljet. Both methods offer potential advantages such as direct patterning, which reduces waste, enables thin film production, and allows for the control of alloy composition. For the first time, palladium-silver alloys have been produced via inkjet printing using a palladium-silver metal organic decomposition (MOD) ink, which alloys at a temperature of 300 °C with nitrogen. Similarly, this study also demonstrates a pioneering approach for Aerosol Jet printing, showing the potential of a novel room-temperature method, for the deposition of palladium-silver MOD inks. This low temperature approach is considered an important development as palladium-silver MOD inks are originally designed for deposition on heated substrates.
Biologically derived hierarchical structural materials not only boast energyefficient processing but also exhibit impressive mechanical performance. Silk stands as the gold standard in hierarchical fiber production, leveraging a unique combination of advantages. Nevertheless, the artificial replication of silk poses technical challenges related to precision processing and comprehensive molecular control. To address such issues, this study investigates the hierarchical assembly of solid regenerated silk in an air atmosphere, facilitated by the incorporation of carbon nanotube (CNT) seeding. Results obtained highlight that this CNT seeding facilitates multiscale structure development in response to post-spin tensile stress. Such CNT bridged structure assembly bypasses some natural processing control variables (pH, ions) and the necessary solvent immersed state for conventional silk post-drawing. Combining secondary electron hyperspectral imaging and 3D synchrotron X-ray ptychotomography, this study reports silk protein conversion from a disordered as-spun state to a longitudinal orientated semi-crystalline nano structure during drawing. The development of microscale structure during the drawing process is attributed to the presence of CNTs, yielding mechanical properties comparable to, and frequently surpassing, those exhibited by native fibers. These findings collectively propose a framework for exploring novel processing routes and offer a practical means controlling self-assembly in silk materials.
Assessing the Quality of Oxygen Plasma Focused Ion Beam (O-PFIB) Etching on Polypropylene Surfaces Using Secondary Electron Hyperspectral Imaging. (2023, Polymers)
The development of Focused Ion Beam–Scanning Electron Microscopy (FIB-SEM) systems has provided significant advances in the processing and characterization of polymers. A fundamental understanding of ion–sample interactions is still missing despite FIB-SEM being routinely applied in microstructural analyses of polymers. This study applies Secondary Electron Hyperspectral Imaging to reveal oxygen and xenon plasma FIB interactions on the surface of a polymer (in this instance, polypropylene). Secondary Electron Hyperspectral Imaging (SEHI) is a technique housed within the SEM chamber that exhibits multiscale surface sensitivity with a high spatial resolution and the ability to identify carbon bonding present using low beam energies without requiring an Ultra High Vacuum (UHV). SEHI is made possible through the use of through-the-lens detectors (TLDs) to provide a low-pass SE collection of low primary electron beam energies and currents. SE images acquired over the same region of interest from different energy ranges are plotted to produce an SE spectrum. The data provided in this study provide evidence of SEHI’s ability to be a valuable tool in the characterization of polymer surfaces post-PFIB etching, allowing for insights into both tailoring polymer processing FIB parameters and SEHI’s ability to be used to monitor serial FIB polymer surfaces in situ.
Chemical imaging (CI) is the spatial identification of molecular chemical composition and is critical to characterising the (in-) homogeneity of functional material surfaces. Nanoscale CI on bulk functional material surfaces is a longstanding challenge in materials science and is addressed here.
We demonstrate the feasibility of surface sensitive CI in the scanning electron microscope (SEM) using colour enriched secondary electron hyperspectral imaging (CSEHI). CSEHI is a new concept in the SEM, where secondary electron emissions in up to three energy ranges are assigned to RGB (red, green, blue) image colour channels. The energy ranges are applied to a hyperspectral image volume which is collected in as little as 50 s. The energy ranges can be defined manually or automatically.
Manual application requires additional information from the user as first explained and demonstrated for a lithium metal anode (LMA) material, followed by manual CSEHI for a range of materials from art history to zoology.
We introduce automated CSEHI, eliminating the need for additional user information, by finding energy ranges using a non-negative matrix factorization (NNMF) based method. Automated CSEHI is evaluated threefold: (1) benchmarking to manual CSEHI on LMA; (2) tracking controlled changes to LMA surfaces; (3) comparing automated CSEHI and manual CI results published in the past to reveal nanostructures in peacock feather and spider silk. Based on the evaluation, CSEHI is well placed to differentiate/track several lithium compounds formed through a solution reaction mechanism on a LMA surface (eg. lithium carbonate, lithium hydroxide and lithium nitride). CSEHI was used to provide insights into the surface chemical distribution on the surface of samples from art history (mineral phases) to zoology (di-sulphide bridge localisation) that are hidden from existing surface analysis techniques. Hence, the CSEHI approach has the potential to impact the way materials are analysed for scientific and industrial purposes.
Aerosol jet printing polymer dispersed liquid crystals on highly curved optical surfaces and edges. (2022, Scientific Reports)
We demonstrate a new technique for producing Polymer Dispersed Liquid Crystal (PDLC) devices utilising aerosol jet printing (AJP). PDLCs require two substrates to act as scaffold for the Indium Tin Oxide electrodes, which restricts the device geometries. Our approach precludes the requirement for the second substrate by printing the electrode directly onto the surface of the PDLC, which is also printed. The process has the potential to be precursory to the implementation of non-contact printing techniques for a variety of liquid crystal-based devices on non-planar substrates. We report the demonstration of direct deposition of PDLC films onto non-planar optical surfaces, including a functional device printed over the 90° edge of a prism. Scanning Electron Microscopy is used to inspect surface features of the polymer electrodes and the liquid crystal domains in the host polymer. The minimum relaxation time of the PDLC was measured at 1.3 ms with an 800 Hz, 90 V, peak-to-peak (Vpp) applied AC field. Cross-polarised transmission is reduced by up to a factor of 3.9. A transparent/scattering contrast ratio of 1.4 is reported between 0 and 140 V at 100 Hz.
Powder materials are used in all corners of materials science, from additive manufacturing to energy storage. Scanning electron microscopy (SEM) has developed to meet morphological, microstructural and bulk chemical powder characterization requirements. These include nanoscale elemental analysis and high-throughput morphological assays. However, spatially localized powder surface chemical information with similar resolution to secondary electron (SE) imaging is not currently available in the SEM. Recently, energy filtered (EF-) SEM has been used for surface chemical characterization by secondary electron hyperspectral imaging (SEHI). This review provides a background to existing powder characterization capabilities in the low voltage SEM provided by SE imaging, EDX analysis and BSE imaging and sets out how these capabilities could be extended for surface chemical analysis by applying SEHI to powders, with particular emphasis on air and beam sensitive powder surfaces. Information accessible by SEHI, its advantages and limitations, is set into the context of other chemical characterization methods that are commonly used for assessing powder surface chemistry such as by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).
The applicability of existing powder preparation methods for SEM to SEHI is also reviewed. An alternative preparation method is presented alongside first examples of SEHI characterization of powder surfaces. The commercial powder materials used as examples were carbon-fiber/polyamide composite powder feedstock (CarbonMide®) used in additive manufacturing and powders consisting of lithium nickel cobalt oxide (NMC). SEHI is shown to differentiate bonding present at carbonaceous material surfaces and extract information about the work function of metal oxide surfaces. The surface sensitivity of SEHI is indicated by comparison of pristine powders to those with surface material added in preparation. A minimum spatial localization of chemical information of 55 nm was achieved in differentiating regions of NMC surface chemistry by distinct SE spectra.
The study of mechanical and chemical phenomena arising within a material that is being subjected to external stress is termed mechanochemistry (MC). Recent advances in MC have revealed the prospect not only to enable a greener route to chemical transformations but also to offer previously unobtainable opportunities in the production and screening of biomaterials. To date, the field of MC has been constrained by the inability of current characterisation techniques to provide essential localised multiscale chemically mapping information. A potential method to overcome this is secondary electron hyperspectral imaging (SEHI). SEHI is a multiscale material characterisation technique applied within a scanning electron microscope (SEM). Based on the collection of secondary electron (SE) emission spectra at low primary beam energies, SEHI is applicable to the chemical assessment of uncoated polymer surfaces. Here, we demonstrate that SEHI can provide in situ MC information using poly(glycerol sebacate)-methacrylate (PGS-M) as an example biomaterial of interest. This study brings the use of a bespoke in situ SEM holder together with the application of SEHI to provide, for the first time, enhanced biomaterial mechanochemical characterisation.
Image Correction and In Situ Spectral Calibration for Low-Cost, Smartphone Hyperspectral Imaging (2022, Remote Sensing)
Developments in the portability of low-cost hyperspectral imaging instruments translate to significant benefits to agricultural industries and environmental monitoring applications. These advances can be further explicated by removing the need for complex post-processing and calibration. We propose a method for substantially increasing the utility of portable hyperspectral imaging. Vertical and horizontal spatial distortions introduced into images by ‘operator shake’ are corrected by an in-scene reference card with two spatial references. In situ light-source-independent spectral calibration is performed. This is achieved by a comparison of the ground-truth spectral reflectance of an in-scene red–green–blue target to the uncalibrated output of the hyperspectral data. Finally, bias introduced into the hyperspectral images due to the non-flat spectral output of the illumination is removed. This allows for low-skilled operation of a truly handheld, low-cost hyperspectral imager for agriculture, environmental monitoring, or other visible hyperspectral imaging applications.
Strengthening preclinical testing to increase safety in surgical mesh (2024, Nature Reviews)
Inflammatory and fibrotic responses to polypropylene mesh led to the withdrawal of this practice for treatment of stress urinary incontinence and pelvic organ prolapse in women in some countries. Improved material testing has been urged. We report poor responses of polypropylene mesh to repeated mechanical distension and macrophage interrogation. These results from preclinical in vitro testing show the potential of this approach for testing and improving materials before their introduction into the clinic.
Characterization and quantification of oxidative stress induced particle debris from polypropylene surgical mesh (2022, Nanoselect)
Explanted polypropylene (PP) surgical mesh has frequently been reported to show surface alterations, such as cracks and flaking. However, to date the consequence of PP mesh degradation is not clearly understood, particularly its potential to influence the biological host response of surrounding tissues. Of particular concern is a possible host reaction to polypropylene particles released through degradation of surgical mesh in vivo. This concern is driven by previous studies which have postulated that an oxidative stress environment has the potential to etch away particles from the surface of a PP fibers. The release of such particles is of considerable significance as particles in the nano- to micro range have been shown to have the capacity to irritate cells and stimulate the immune system. The authors are not aware of any previous studies that have attempted to characterize, quantify or identify any particles released from PP mesh after exposure to an oxidative stress environment. Characterization of the PP mesh, post oxidative stress exposure, including identification of particles was achieved through application of a range of techniques: low voltage-scanning electron microscopy (LV-SEM), pyrolysis gas chromatography mass spectrometry (Pyr-GCMS), nano-Fourier transform infrared spectroscopy (nano-FTIR), scattering-type, scanning near-field optical microscopy (s-SNOM), atomic force microscopy (AFM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and uniaxial tensile testing. The findings of this study indicate that oxidative stress alone is a major factor in the production of PP particle debris. PP debris identified within solution, using Pyr-GCMS, was shown to be in order of the micron scale.
Titanium-coated polypropylene (Ti-PP) mesh was introduced in 2002 as a surgical mesh for the treatment of hernias and shortly after for pelvic floor surgery, with the aim of improving biocompatibility when compared to non-titanised/regular PP mesh implants. The application of a titanium coating could also be beneficial to address concerns regarding the exposure of PP in an in vivo environment. Many studies have shown that PP, although it is widely accepted as a stable polymer, is subject to oxidation and degradation, such degradation affects the mechanical behavior, that is, the stiffness and tensile strength of PP mesh. Despite the wide clinical use of Ti-PP surgical meshes, no study has yet investigated the residual material properties post clinical deployment and subsequent explantation. In this study, two explanted Ti-PP mesh samples each having different incorporation durations from two patients were examined. Material analysis conducted within this study includes the following techniques: attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, low voltage – scanning electron microscopy (LV-SEM), backscattered electron (BSE) imaging, energy dispersive X-ray spectroscopy (EDS) and secondary election hyperspectral imaging (SEHI). The hypothesis of this study is that the Ti coating successfully shields the PP mesh from oxidative stress in vivo and thus protects it from degradation. The results of this analysis show for the first time evidence of bulk oxidation, surface degradation, and environmental stress cracking on explanted Ti-PP meshes.
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Currently, in vitro testing examines the cytotoxicity of biomaterials but fails to consider how materials respond to mechanical forces and the immune response to them; both are crucial for successful long-term implantation. A notable example of this failure is polypropylene mid-urethral mesh used in the treatment of stress urinary incontinence (SUI). The mesh was largely successful in abdominal hernia repair but produced significant complications when repurposed to treat SUI. Developing more physiologically relevant in vitro test models would allow more physiologically relevant data to be collected about how biomaterials will interact with the body. This study investigates the effects of mechanochemical distress (a combination of oxidation and mechanical distention) on polypropylene mesh surfaces and the effect this has on macrophage gene expression. Surface topology of the mesh was characterised using SEM and AFM; ATR-FTIR, EDX and Raman spectroscopy was applied to detect surface oxidation and structural molecular alterations. Uniaxial mechanical testing was performed to reveal any bulk mechanical changes. RT-qPCR of selected pro-fibrotic and pro-inflammatory genes was carried out on macrophages cultured on control and mechanochemically distressed PP mesh. Following exposure to mechanochemical distress the mesh surface was observed to crack and craze and helical defects were detected in the polymer backbone. Surface oxidation of the mesh was seen after macrophage attachment for 7 days. These changes in mesh surface triggered modified gene expression in macrophages. Pro-fibrotic and pro-inflammatory genes were upregulated after macrophages were cultured on mechanochemically distressed mesh, whereas the same genes were down-regulated in macrophages exposed to control mesh. This study highlights the relationship between macrophages and polypropylene surgical mesh, thus offering more insight into the fate of an implanted material than existing in vitro testing.
Polymer crazing is a phenomenon observable as fine cracks on the surface of a material. For polymers crazing is often a precursor to mechanical failure with the capacity of a craze to propagate and develop into a larger structural crack. In this study polypropylene (PP) fibres, known to be susceptible to crazing, were subjected to argon (Ar) plasma treatment with the aim of creating a crosslinked surface that displays the ability to withstand the formation of crazes. To evaluate Ar plasma success at achieving this aim: the resulting Ar treated fibres were characterised to evaluate their capacity to avoid the formation of crazes and also identify any changes induced to the chemical and mechanical properties of PP as a consequence of Ar plasma exposure. This analysis was conducted by application of low voltage (LV)-scanning electron microscopy imaging, uniaxial tensile testing, Energy Dispersive X-ray Spectroscopy (EDS) and attenuated total reflectance - fourier-transform infrared spectroscopy (ATR-FTIR). The results of this study highlight the potential of the application of Ar plasma to influence the formation of crazes on PP fibres after exposure to repeated dynamic distention cycles. Ar plasma treated PP also showed a capacity to reduce bulk fibre oxidation when compared to that of non-treated PP when exposed to dynamic distention and subsequently immersed in an oxidative stress environment.
Cancer is a becoming a huge social and economic burden on society, becoming one of the most significant barriers to life expectancy in the 21st century. In particular, breast cancer is one of the leading causes of death for women. One of the most significant difficulties to finding efficient therapies for specific cancers, such as breast cancer, is the efficiency and ease of drug development and testing. Tissue-engineered (TE) in vitro models are rapidly developing as an alternative to animal testing for pharmaceuticals. Additionally, porosity included within these structures overcomes the diffusional mass transfer limit whilst enabling cell infiltration and integration with surrounding tissue. Within this study, we investigated the use of high-molecular-weight polycaprolactone methacrylate (PCL–M) polymerised high-internal-phase emulsions (polyHIPEs) as a scaffold to support 3D breast cancer (MDA-MB-231) cell culture. We assessed the porosity, interconnectivity, and morphology of the polyHIPEs when varying mixing speed during formation of the emulsion, successfully demonstrating the tunability of these polyHIPEs. An ex ovo chick chorioallantoic membrane assay identified the scaffolds as bioinert, with biocompatible properties within a vascularised tissue. Furthermore, in vitro assessment of cell attachment and proliferation showed promising potential for the use of PCL polyHIPEs to support cell growth. Our results demonstrate that PCL polyHIPEs are a promising material to support cancer cell growth with tuneable porosity and interconnectivity for the fabrication of perfusable 3D cancer models.
In this work, different types of carbon dots (CDs) based on citric acid as a precursor were synthesized using an efficient procedure to purify these materials from low molecular by-products and fluorophores. Their structural and optical characteristics were elaborated and compared to commercially available graphene quantum dots. The mechanism of their action in photopolymerization processes was evaluated. Obtained materials proved to perform well in the development of effective photoinitiating systems for 3D printing applications. The morphology and chemical composition of obtained hydrogel printouts were profoundly characterized via SEM, AFM, Nano-FTIR, and s-SNOM.
