Wanida Janvikul

This study developed three-dimensional (3D)-printable polypropylene random copolymer (PPR)-based composites incorporating halloysite nanotubes (HNTs) and a nucleating agent (NA) for extrusion-based additive manufacturing. The combined effects of HNT loading (0–5 wt %), NA incorporation (0.1 wt %), and postprinting thermal annealing on their thermal behavior, crystallization, printability, and mechanical performance were systematically investigated. Thermogravimetric analysis (TGA) demonstrated enhanced thermal stability with HNT addition due to the barrier effect of the aluminosilicate structure. Differential scanning calorimetry (DSC) revealed that HNTs had limited influence on crystallization behavior, whereas NA significantly increased the crystallization and onset temperatures, indicating accelerated crystallization kinetics without altering the dominant α-phase crystal structure, as confirmed by X-ray diffraction (XRD). HNT incorporation improved filament dimensional stability during extrusion, yielding uniform, near-circular cross sections compared to neat PPR, and enhanced build plate adhesion and dimensional stability during printing without external adhesives. Mechanically, HNT addition increased stiffness but reduced impact strength. Postprinting thermal annealing increased melting enthalpy and refined crystalline morphology, resulting in partial recovery of impact strength in HNT-filled samples, although the values remained below that of neat PPR. The combined use of HNT incorporation, nucleation control, and thermal annealing provided an effective strategy to enhance the 3D-printability and mechanical performance of PPR-based composites.

Treatment of chronic wounds is challenging due to a variety of interconnected intrinsic (patient-related) and extrinsic (external/local) factors that disrupt the normal, orderly process of wound repair. Although human platelet lysate (hPL)-based treatment offers a cost-effective option for chronic wound diseases, the inherent limitations of hPL gel (hPLG), particularly its diminished structural integrity and limited retention of growth factors (GFs), hinder its utility for treating chronic wounds. Therefore, a novel cross-linked plasma-treated mesoporous silica nanoparticle/carboxymethyl chitosan composite (xPMC)-embedded hPLG hydrogel (xPMC/hPLG), designed to prolong fibrin integrity and enhance local retention of bioactive factors, was developed, characterized, and assessed for fibrin structural integrity and biological performance, including cellular chemotaxis and proliferation. Microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) analyses demonstrated that xPMC possessed high porosity and interconnectivity, with evenly distributed fibrin within the pores of the composite hydrogel. Compared with hPLG alone, finer fibrin fibers with increased density were observed in xPMC/hPLG. The observed interpenetrating network structure of xPMC/hPLG was associated with the significantly reduced in vitro degradation of the composite hydrogel. Moreover, it exhibited controlled local release of the total protein and key growth factors, i.e., platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-β1 (TGF-β1). Importantly, xPMC/hPLG more effectively enhanced the recruitment and proliferation of periodontal fibroblasts than hPLG. This superior induction of fibroblast recruitment was at least partly mediated by PDGF-BB. In conclusion, the developed xPMC/hPLG composite hydrogel demonstrated prolonged structural integrity, extended release of bioactive GFs, and enhanced cell migration and proliferation. Future in vivo studies will further validate this composite hydrogel for enhancing the success of chronic wound treatment.

This study aimed to develop a bifunctional nanomaterial that could simultaneously adsorb zoledronic acid (ZA) and release geranylgeraniol (GGOH) to reverse ZA-induced cytotoxicity. The synthesized aluminum-doped mesoporous silica nanomaterial (AM) was subsequently amine-functionalized by 3-aminopropyltriethoxysilane, generating both amine- and aluminum-containing nanomaterial (NAM), to enhance the ability of nanoparticles to adsorb GGOH. The comprehensive characterization results confirmed the successful aluminum-doping and amine-functionalization of the nanoparticles. The results acquired from both thermogravimetric analysis and high-performance liquid chromatography demonstrated that NAM, rather than AM, served as a good nanocarrier for GGOH loading and controlled-releasing. NAM exhibited up to 12.48% GGOH loading efficiency and GGOH sustained release for over 10 days with a release profile best fitted by the Higuchi model (R ² = 0.9868), indicating a diffusion-controlled mechanism. Although AM demonstrated much higher ZA adsorption (>95%), NAM still retained moderate ZA adsorption (∼30%). In vitro assays using RAW 264.7 murine cells revealed that GGOH-loaded NAM was noncytotoxic and completely reversed ZA-induced cytotoxicity and metabolic impairment. Furthermore, it displayed negligible hemolytic activity (<0.5%). The combination of targeted drug delivery and bisphosphonate sequestration via nanostructured silica nanocarriers presents a promising therapeutic approach with translational potential in the prevention of medication-related osteonecrosis of the jaw. The promising cellular results, serving as a preclinical foundation, provide a stepping stone toward in vivo applications.

Platelets play a pivotal role in initiating bone fracture healing. However, the interaction between platelets and bone cements used for fracture repair remains relatively unexplored. This study investigated the platelet response to recently developed urethane dimethacrylate-based bone cements containing 8% (w/w) monocalcium phosphate monohydrate (MCPM) and/or 5% (w/w) epsilon-polylysine (PLS). All experimental bone cements achieved final monomer conversions of 75-78%, compared with the 86% conversion of the commercial PMMA bone cement Kyphon. The MCPM and PLS microparticles, varying in size, were dispersed within the glass-filler-incorporated polymer matrix. In contrast to Kyphon, all experimental cements exhibited significantly smoother and more hydrophilic surfaces. Bone cements incorporating PLS, with or without MCPM, effectively activated platelets by inducing cellular adhesion, aggregation, and extracellular-signal-regulated kinase (ERK) activation, comparable to Kyphon. Flow cytometry analysis demonstrated a statistically significant increase in CD62P-positive platelets following exposure to PLS-incorporated bone cements and exogenously administered PLS in a concentration-dependent manner, but not with Kyphon. A wound healing assay revealed a 2-fold enhancement in wound closure within 24 h and exceeding 85% at 48 h by bone cements containing PLS, with or without MCPM, and Kyphon. Notably, platelet-derived growth factor BB (PDGF-BB) secretion was significantly elevated, specifically after platelet exposure to PLS-incorporated bone cements, a phenomenon not observed with Kyphon. Interestingly, PDGF-BB neutralization attenuated wound closure induced by the PLS-incorporated bone cements. In conclusion, the urethane dimethacrylate-based bone cements containing PLS demonstrated a significant enhancement in platelet activation and PDGF-BB secretion, which, at least partly, enhanced in vitro wound closure. The results suggest that PDGF-BB plays a crucial role in the PLS-mediated enhancement of wound healing in these bone cements.

A set of filaments for fused deposition modeling (FDM) three-dimensional (3D) printing was developed from the ternary blends of polypropylene random copolymer (PPR or P), high density polyethylene (HDPE or E), and thermoplastic polyurethane (TPU or T), formulated with different weight ratios of polymers, i.e., 80:20:0, 70:20:10, 60:20:20, and 50:20:30, respectively, and coded as P80E20T0, P70E20T10, P60E20T20, and P50E20T30, respectively. The blend composition was optimized to obtain both high-quality filaments with low ovality and FDM-fabricated objects with minimized warpage and good interlayer bonding. The crystallization and crystalline morphologies of individual polymers in the blend filaments were comprehensively analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarized light optical microscopy (PLOM). It was found that HDPE acted as crystalline nuclei for PPR crystallization; PPR appeared to crystallize more readily at a slightly higher T _c with somewhat greater crystallinity. Meanwhile, TPU explicitly restricted the crystallization of both polyolefins; decreases in both the size and growth rate of their spherulites were observed. The PLOM and SEM results indicated that the surface morphology of the ternary blends was not absolutely phase-separated; an increasing number of TPU droplets inherently imbedded at the boundary of the polyolefin aggregate phase when a higher TPU quantity was integrated. Consequently, the warpage deformation and layer interfusion of the as-printed articles were most remarkably improved when P50E20T30 was used. Nonetheless, the incorporation of relatively flexible TPU material into the PPR-based filaments inevitably reduced their mechanical performance; the flexural strength and modulus of the highest-quality 3D-printed P50E20T30 object were fairly decreased by approximately 25% and 12%, respectively.

This investigation developed new composite bone cements using urethane dimethacrylate (UDMA), poly(propylene glycol) dimethacrylate (PPGDMA), and hydroxyethyl methacrylate (HEMA), with micrometer-sized aluminosilicate glass filler. Monocalcium phosphate monohydrate (MCPM) and hydroxyapatite (HA) particles were added to enhance biological performance, particularly osteo-immunomodulation. Free radical polymerization was triggered by mixing two pastes containing either benzoyl peroxide (BPO, an initiator) or N-tolyglycine glycidyl methacrylate (NTGGMA, an activator). Increasing butylated hydroxytoluene (BHT, an inhibitor) enabled a suitable delay after mixing at 25 °C for placement. At 37 °C, the delay time was reduced and the final conversion was enhanced. Findings also demonstrated the biocompatibility of the developed bone cement toward osteo-immunological cell lineages, including mesenchymal stem cells (MSCs), fibroblasts, osteoclast precursor RAW 246.7 cells, and peripheral blood mononuclear cells (PBMCs). Notably, the cement with both MCPM and HA combined facilitated sufficient MSC growth, enabling subsequent mineralization while concurrently suppressing the proliferation of fibroblasts, osteoclast progenitors, and PBMCs. Furthermore, composite cement exhibited the capacity to differentially regulate osteoblast differentiation, cell-(in)dependent mineralization, osteoclastogenesis, and PBMC-mediated inflammatory responses at both cellular and molecular levels in vitro. These observations suggested their potential use for bone repair, especially in cases of inflammation-associated bone defects.

Computer-Aided Design and Applications is an international journal on the applications of CAD and CAM. It publishes papers in the general domain of CAD plus in emerging fields like bio-CAD, nano-CAD, soft-CAD, garment-CAD, PLM, PDM, CAD data mining, CAD and the internet, CAD education, genetic algorithms and CAD engines. The journal is aimed at all developers and users of CAD technology to ptovide CAD solutions for various stages of design and manufacturing. The journal publishes all about Computer-Aided Design and Computer-Aided technologies.

Blend filaments of acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) were prepared at different weight ratios, i.e., 100:0, 70:30, 50:50, 30:70, and 0:100, for FDM printing; the prepared filaments, with an average diameter of 2.77 ± 0.19 mm, were encoded as A100, A70T30, A50T50, A30T70, and T100, respectively. The properties and printability of the filaments were thoroughly investigated. The blend composition, as well as the printing parameters, were optimized to obtain the FDM-printed objects with a well-defined surface structure and minimized warpages. The glass transition temperatures of ABS and TPU in the blends were not much altered from those of the parent filaments, whereas the thermal degradation characteristics of the blend filaments still fell between those of the neat filaments. The fractured surfaces of the filaments, observed by SEM, appeared smoother when higher amounts of TPU integrated; the smoothest surface of the ABS-based filament was found in A30T70, indicating the well-compatible blend characteristic. This was also confirmed by its rheological behavior examined by a parallel plate rheometer at 225 °C. Not only was the printability of the filaments improved, but also the warpages of the 3D-printed specimens were decreased when increasing amount of TPU was incorporated into the filaments. Among the printed objects, the A30T70 specimen exhibited the evenest surface morphology with the lowest surface roughness value of 32.9 ± 13.2 nm and the most uniform and consistent linear printing structure when being fabricated at the nozzle temperature of 225 °C and the printing bed temperature of 60 °C. However, the incorporation of TPU into the filaments markedly cut down both strength and modulus values of the fabricated materials up to about half but assisted the printed articles to absorb more energy, demonstrating that this polymer served as a good and effective toughener for ABS.

Clindamycin (CDM)/geranylgeraniol (GGOH)-loaded plasma-treated mesoporous silica nanoparticles/carboxymethyl chitosan composite hydrogels (CHG60 and CHG120) were developed for the prevention of medication-related osteonecrosis of the jaw associated with bisphosphonates (MRONJ-B). The pore structure and performances of CHGs, e.g., drug release profiles and kinetics, antibacterial activity, zoledronic acid (ZA)-induced cytotoxicity reversal activity, and acute cytotoxicity, were evaluated. The bioinspired platform mimicking in vivo fibrin matrices was also proposed for the in vitro/in vivo correlation. CHG120 was further encapsulated in the human-derived fibrin, generating FCHG120. The SEM and μCT images revealed the interconnected porous structures of CHG120 in both pure and fibrin-surrounding hydrogels with %porosity of 75 and 36%, respectively, indicating the presence of fibrin inside the hydrogel pores, besides its peripheral region, which was evidenced by confocal microscopy. The co-presence of GGOH moderately decelerated the overall releases of CDM from CHGs in the studied releasing fluids, i.e., phosphate buffer saline-based fluid (PBB) and simulated interstitial fluid (SIF). The whole-lifetime release patterns of CDM, fitted by the Ritger-Peppas equation, appeared nondifferentiable, divided into two releasing stages, i.e., rapid and steady releasing stages, whereas the biphasic drug release patterns of GGOH were observed with Phase I and II releases fitted by the Higuchi and Ritger-Peppas equations, respectively. Notably, the burst releases of both drugs were subsided with lengthier durations (up to 10-12 days) in SIF, compared with those in PBB, enabling CHGs to elicit satisfactory antibacterial and ZA cytotoxicity reversal activities for MRONJ-B prevention. The fibrin network in FCHG120 further reduced and sustained the drug releases for at least 14 days, lengthening bactericidal and ZA cytotoxicity reversal activities of FCHG and decreasing in vitro and in ovo acute drug toxicity. This highlighted the significance of fibrin matrices as appropriate in vivo-like platforms to evaluate the performance of an implant.