Elnaz Tamjid

3D-printed scaffolds are crucial in bone tissue engineering, providing a bioactive porous network for osteogenesis. However, their limited angiogenesis and mechanical strength poses challenges for effective bone repair. In this study, a 3D-printed scaffold based on polycaprolactone (PCL) containing magnesium particles (Mg) and laponite nanoparticles (LAP) loaded with pre-osteoblastic cells (MC₃T₃-E₁) was developed to simultaneously improve mechanical properties, and exhibit coupled osteoblastic differentiation and vascularization. Adding Mg and LAP particles to PCL increased cell viability by 21% and 10% for scaffolds containing Mg (PM) and Mg-LAP (PML), respectively. The hierarchical 3D structure was investigated by scanning electron microscopy, while the surface properties and the structural analysis were studied by FTIR, DLS, XRD, and wettability tests. The PM and PML showed 20% and 60% enhancement in Young’s modulus as compared to the P scaffold, i.e., remarkably in the range of natural bone. Noticeably, adding Mg and LAP increased the alkaline phosphate enzyme activity of pre-osteoblastic cells by 28-fold and 20-fold in comparison with the P scaffolds and non-treated control samples. Moreover, PML printed scaffold showed significantly higher vascularization compared to P scaffolds in chorioallantoic membrane (CAM) assay. The 3D-printed scaffolds developed in this study demonstrated coupled osteogenesis and angiogenesis, paving the way for innovative biomaterials in bone tissue regeneration.

It is essential to develop new strategies for wound treatment and skin reconstruction, particularly by scaffolds that replicate the structure and function of native skin. A bilayer scaffold was developed using three-dimensional (3D) bioprinting, based on a uniform chitosan-based formulation for both layers, maintaining material uniformity while offering structural support and promoting cell adhesion. The upper chitosan layer, embedded with NHEK-Neo, is stiffer and mimics the epidermis, while the softer lower layer contains embedded HFFs and HFSCs, mimicking the dermis. Moreover, the softer layer was infused with recombinant decorin (DCN) proteoglycans for skin repair through controlled release. The scaffold facilitates effective fluid management. Its positive contact angle suggests sufficient wettability. The scaffold layers have high water content and swelling capacity. The epidermis displayed lower compressive strength due to its more protective and less hydrated nature. Rheological analysis confirmed the scaffold’s viscoelastic behavior. Chitosan-gel had high cytocompatibility. Chitosan scaffolds supplemented with DCN proteoglycans had enhanced blood entrapment and clotting. The scaffold’s timely biodegradation may reduce prolonged material exposure and support safe tissue integration. This scaffold has potential in the treatment of acute and chronic wounds.

Biodegradable polymer nanocomposites (BPNCs) are advanced materials that have gained significant attention over the past 20 years due to their advantages over conventional polymers. BPNCs are eco-friendly, cost-effective, contamination-resistant, and tailorable for specific applications. Nevertheless, their usage is limited due to their unsatisfactory physical and mechanical properties. To improve these properties, nanofillers are incorporated into natural polymer matrices, to enhance mechanical durability, biodegradability, electrical conductivity, dielectric, and thermal properties. Despite the significant advances in the development of BPNCs over the last decades, our understanding of their dielectric, thermal, and electrical conductivity is still far from complete. This review paper aims to provide comprehensive insights into the fundamental principles behind these properties, the main synthesis, and characterization methods, and their functionality and performance. Moreover, the role of nanofillers in strength, permeability, thermal stability, biodegradability, heat transport, and electrical conductivity is discussed. Additionally, the paper explores the applications, challenges, and opportunities of BPNCs for electronic devices, thermal management, and food packaging. Finally, this paper highlights the benefits of BPNCs as biodegradable and biodecomposable functional materials to replace traditional plastics. Finally, the contemporary industrial advances based on an overview of the main stakeholders and recently commercialized products are addressed.

Cardiac troponin-I (cTnI) is a well-known biomarker for the diagnosis and control of acute myocardial infarction in clinical practice. To improve the accuracy and reliability of cTnI electrochemical immunosensors, we propose a multilayer nanostructure consisting of Fe₃O₄-COOH labeled anti-cTnI monoclonal antibody (Fe₃O₄-COOH-Ab₁) and anti-cTnI polyclonal antibody (Ab₂) conjugated on Au-Ag nanoparticles (NPs) decorated on a metal–organic framework (Au-Ag@ZIF-67-Ab₂). In this design, Fe₃O₄-COOH was used for separation of cTnI in specimens and signal amplification, hierarchical porous ZIF-67 extremely enhanced the specific surface area, and Au-Ag NPs synergically promoted the conductivity and sensitivity. They were additionally employed as an immobilization platform to enhance antibody loading. Electron microscopy images indicated that Ag-Au NPs with an average diameter of 1.9 ± 0.5 nm were uniformly decorated on plate-like ZIF-67 particles (with average size of 690 nm) without any agglomeration. Several electrochemical assays were implemented to precisely evaluate the immunosensor performance. The square wave voltammetry technique exhibited the best performance with a sensitivity of 0.98 mA mL cm⁻² ng⁻¹ and a detection limit of 0.047 pg mL⁻¹ in the linear range of 0.04 to 8 ng mL⁻¹.