2D Ti3C2Tx (MXene) is attracting significant attention in tissue engineering. The incorporation of these promising materials into conventional scaffolds remains challenging, particularly with physicochemical properties compatible with biological systems. Melt electrowriting (MEW) has emerged as a powerful additive manufacturing technique for biofabrication of customized three-dimensional (3D) scaffolds composed of bioactive materials. This study introduces MEW of 2D MXene and polycaprolactone (PCL) nanocomposite scaffolds for tissue engineering applications. First, Ti3C2Tx was functionalized using (3-aminopropyl) triethoxysilane (referred to as f-MXene) to obtain a blended nanocomposite in PCL matrix (referred to as MX/PCL). Fourier transform infrared spectroscopy revealed the nanocomposite composition. X-ray diffraction analysis showed the reduced crystallinity in PCL after incorporation of f-MXene. Differential scanning calorimetry helped to establish the optimal MEW parameters. Thermogravimetric analysis conducted on nanocomposites containing 0.1, 0.5, and 1% (w/w) f-MXene showed the thermal stability of MXene during the MEW process. The extrudability and printability of the nanocomposites with varying concentrations was demonstrated using MEW in 0–90-degree mesh scaffolds with fine filament dimensions. Scanning electron microscopy and Energy-dispersive x-ray spectroscopy mapping showed the shape fidelity, printing accuracy, and structural integrity of 3D MEW scaffolds with uniform distribution of f-MXene, respectively. Further characterization showed the concentration-dependent enhancement in hydrophilicity and compressive modulus and yield strength of scaffolds upon integration of f-MXene. Atomic force microscopy analysis demonstrated that the topography of the 3D MEW MX/PCL scaffolds changed compared to the pristine PCL and the roughness of the surfaces increased as the concentration of the f-MXene increased. Accelerated degradation tests demonstrated that increasing filler concentration in the reinforced scaffolds progressively delayed degradation compared to the control. The in vitro characterization showed the adherence of MC3T3-E1 preosteoblast cells on MX/PCL scaffolds and their enhanced osteogenic differentiation. The findings indicate that 3D printed MX/PCL nanocomposite scaffolds have significant potential as mechanically robust scaffolds with controlled degradation rate and cytocompatibility for tissue regeneration, with properties tunable for specific applications.
Soft lithography with microfabricated molds is a widely used manufacturing method. Recent advancements in 3D printing technologies have enabled microscale feature resolution, providing a promising alternative for mold fabrication. It is well established that the curing of PDMS is influenced by parameters such as temperature, time, and curing agent ratio. This study was conducted to address inconsistencies in PDMS curing observed when using different 3D-printed mold materials during the development of a Lab-on-a-Chip (LoC) system, which is typically employed for investigating the effect of hydrodynamic cavitation on blood clot disintegration. To evaluate the impact of mold material on PDMS curing behavior, PDMS was cast into molds made from polylactic acid (PLA), polyethylene terephthalate (PET), resin, and aluminum, and cured at controlled temperatures (55, 65, and 75 °C) for various durations (2, 6, and 12 h). Curing performance was assessed using Soxhlet extraction, Young’s modulus calculations derived from Atomic Force Microscopy (AFM), and complementary characterization methods. The results indicate that the mold material significantly affects PDMS curing kinetics due to differences in thermal conductivity and surface interactions. Notably, at 65 °C, PDMS cured in aluminum molds had a higher Young’s modulus (~1.84 MPa) compared to PLA (~1.23 MPa) and PET (~1.17 MPa), demonstrating that the mold material can be leveraged to tailor the mechanical properties. These effects were especially pronounced at lower curing temperatures, where PLA and PET molds offered better control over PDMS elasticity, making them suitable for applications requiring flexible LoC devices. Based on these findings, 3D-printed PLA molds show strong potential for PDMS-based microdevice fabrication.
Titanium nitride (TiN) is an advantageous material for plasmonic applications and is suitable for extreme conditions in which conventional plasmonic materials such as gold (Au) cannot be utilized. In this study, TiN and Au nanodisk arrays with different lattice spacing (Λ) were fabricated using the electron beam lithography (EBL) method to increase the quality factor of TiN. At a period of 550 nm, the TiN nanodisk arrays demonstrate a higher sensitivity, 412.79 nm·RIU−1, with the plasmonic resonance wavelength shifting from 883 nm (n = 1.3335) to 915 nm (n = 1.4069) in the NIR region. The surface lattice resonance (SLR) properties of the produced TiN nanodisk arrays were investigated in detail with Au nanodisk arrays. The TiN nanodisk arrays caused sharp plasmon resonances by creating a localized plasmon vibration mode coupled with the diffractive grazing wave excited by the incident light. The transmission dips obtained at narrower full width at half maximum (FWHM) values caused at least an almost 10-fold improvement in the quality factor compared to localized surface plasmon resonance (LSPR) dips. This study is significant for assessing the surface plasmon resonance characteristics of TiN and Au nanodisk arrays across various periods and indices.
The increasing use of pesticides and their mixtures poses a serious risk to human health and the environment. This increases the demand for simple, cost-effective, and reliable methods for detecting these residues. In this study, a highly sensitive in-house SERS platform based on a metal-insulator-metal (MIM) nanoarray structure was employed to acquire Raman fingerprint spectra of Pyrimethanil (PYM), Imidacloprid (IMI), and Chlormequat chloride (CCC) in pepper juice, yielding spectra with high signal-to-noise ratios. The detection limit for PYM in pepper juice (0.16 mg/kg) was well below both the EFSA (2 mg/kg) and EPA (2 mg/kg) limits. Among the tested pesticides, PYM shows the lowest detection limit, indicating a more efficient signal enhancement for the π-metal interaction. This strong affinity results in significantly enhanced Raman scattering activity. Furthermore, the unsupervised machine learning analysis techniques (e.g., PCA and HCA) used showed a concentration-dependent separation in spiked samples. The same approach also enabled detection and discrimination in real food samples obtained from different regions. These results demonstrate the potential of the developed platform for rapid, on-site monitoring of pesticide residues in complex food matrices.
Polymeric microparticles have triggered critical advancements in drug delivery systems, offering significant improvements in therapeutic efficacy by controlling the delivery while minimizing adverse side effects of the pharmaceuticals. However, conventional microparticle fabrication techniques face several limitations, such as particle size variability, early drug degradation, and production inefficiencies. In this study, we developed a microparticle production system (MPS) in which a precision spraying technology was integrated with a microfabricated nozzle array-based piezoelectric transducer. High-throughput microparticle production was achieved using Poly(D,L-lactide-co-glycolide) (PLGA) dissolved in dichloromethane (DCM) and dimethyl carbonate (DMC). The resulting PLGA microparticles exhibited remarkable consistency in size uniformity with an average diameter of 8.9 ± 1.7 μm. Detailed characterization through scanning electron microscopy (SEM) and focused ion beam (FIB) analyses revealed distinct surface and internal structures and demonstrated the effect of solvent volatility on microparticle morphology. Chloramphenicol (CHL) was used as a model drug, and an encapsulation efficiency of 38.7% and a loading efficiency of 16.2% were achieved. The PLGA microparticles showed sustained CHL release and demonstrated effective antibacterial activity against Escherichia coli (E. coli), highlighting their potential for controlled therapeutic applications. This developed MPS system offers a scalable and efficient approach for producing PLGA-based microparticles with controlled drug release profiles, making it valuable in the industrial-scale production of advanced drug delivery technologies.