Murat Guvendiren

Conventional low-density poly(ethylene) (LDPE) agricultural mulch films generate persistent plastic waste, which has motivated the development of biodegradable mulch films (BDMs) that can provide adequate performance during use while offering improved end-of-life options. Here, composite films containing poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT), microcrystalline cellulose (MCC), and hydroxyapatite (HA) were evaluated for their material properties and suitability as agricultural mulches. Correlation analysis and Elastic Net regression were used to examine composition–property relationships. PBAT primarily governed ductility and tensile performance, whereas MCC significantly increased water absorption because of its hydrophilic character. Water absorption was the most reliably modeled response (training R² = 0.893), while mechanical property models showed limited validation performance, which indicates that composition alone could not fully predict unseen formulations. Several formulations met commercial BDM mechanical requirements. Multi-objective optimization predicted a composition of 9.3/80.7/3.5/6.5 wt% PLA/PBAT/MCC/HA. The combined experimental and modeling framework clarifies composition–property relationships in biodegradable polymer composites and demonstrates how data-driven approaches can guide the formulation of biodegradable agricultural mulch films.

Additive manufacturing (AM), commonly known as 3D printing, has rapidly transformed modern manufacturing, creating a growing demand for engineers with both theoretical knowledge and practical skills. Despite its increasing relevance, AM is often incorporated into engineering curricula as a supplementary tool rather than a fully integrated subject, limiting students’ understanding of fundamental material–process–performance relationships. This study presents the development, implementation, and assessment of an integrated lecture–laboratory framework for AM education at the New Jersey Institute of Technology (NJIT). Two complementary courses were developed: an undergraduate course (Introduction to 3D Printing, CHE 415) and a graduate course (Additive Manufacturing and Applications, CHE 722). The curriculum integrates instruction in AM technologies, materials, and digital workflows with hands-on design challenges, team-based projects, and structured literature reviews, enabling students to engage in the complete design-to-fabrication process. Student learning outcomes were evaluated over multiple academic years using ABET-aligned assessments, grade distributions, and student self-assessments. Results demonstrate consistently high levels of student proficiency and engagement, with strong performance in design, problem-solving, and communication skills. The courses also attracted students from diverse disciplines, underscoring the interdisciplinary nature of AM education. While limitations remain in providing hands-on exposure to a broader range of AM technologies, ongoing expansion of laboratory infrastructure is expected to address these challenges. Overall, this work demonstrates that an integrated, project-based approach effectively bridges theory and practice and provides a scalable model for incorporating AM into engineering curricula.

Additive manufacturing (AM), commonly known as 3D printing, has rapidly transformed modern manufacturing, creating a growing demand for engineers with both theoretical knowledge and practical skills. Despite its increasing relevance, AM is often incorporated into engineering curricula as a supplementary tool rather than a fully integrated subject, limiting students’ understanding of fundamental material–process–performance relationships. This study presents the development, implementation, and assessment of an integrated lecture–laboratory framework for AM education at the New Jersey Institute of Technology (NJIT). Two complementary courses were developed: an undergraduate course (Introduction to 3D Printing, CHE 415) and a graduate course (Additive Manufacturing and Applications, CHE 722). The curriculum integrates instruction in AM technologies, materials, and digital workflows with hands-on design challenges, team-based projects, and structured literature review, enabling students to engage in the complete design-to-fabrication process. Student learning outcomes were evaluated over multiple academic years using ABET-aligned assessments, grade distributions, and student self-assessments. Results demonstrate consistently high levels of student proficiency and engagement, with strong performance in design, problem-solving, and communication skills. The courses also attracted students from diverse disciplines, underscoring the interdisciplinary nature of AM education. While limitations remain in providing hands-on exposure to a broader range of AM technologies, ongoing expansion of laboratory infrastructure is expected to address these challenges. Overall, this work demonstrates that an integrated, project-based approach effectively bridges theory and practice and provides a scalable model for incorporating AM into engineering curricula.

Biodegradable polymers offer a promising solution to the growing issue of global microplastic pollution. To effectively replace conventional plastics, it is essential to develop strategies for tuning the properties of biodegradable polymers without relying on additives. Biaxial stretching promotes anisotropic crystallization in polymer domains, thereby altering the mechanical performance of polymer blends. In this study, we employed a design of experiment (DoE) approach to investigate the effects of biaxial stretching at three drawing temperatures (T_ds) and draw ratios (λs) on a biodegradable blend of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT), aiming to optimize both the strength and ductility. The DoE analysis revealed that the composition, the λ, the interaction between the λ and composition, and the interaction between the T_d and composition significantly affect the elongation at break (ε_Break). For the stress at break (σ_Break), the most influential factors were the interaction between the λ and PLA concentration; a three-way interaction among the λ, PLA, and T_d; the T_d; the λ; and finally the PLA concentration alone. The optimal ε_Break and σ_Break were achieved at a λ = 5 × 5 and T_d = 110 °C, with a composition of 10% PLA and 90% PBAT. The stretched samples exhibited higher crystallinity compared to the pressed samples across all compositions. This work demonstrates that in addition to the composition, the processing parameters, such as the λ and T_d, critically influence the mechanical properties, enabling performance enhancements without the need for compatibilizers or toxic additives.

Microplastic pollution from the agriculture industry presents a growing environmental and public health concern, driven in part by the widespread use of poly(ethylene) (PE)-based mulch. While plastic mulch is essential for sustaining an increasing global population, its contribution to microplastic pollution necessitates alternative solutions. This work addresses the urgent need for biodegradable mulches (BDMs) that match the performance of traditional PE films. A comprehensive methodology is proposed for the development and characterization of novel BDM formulations, informed by scientific literature, regulatory guidelines, commercial practices, and industry standards. The proposed approach emphasizes scalable formulation and processing of biodegradable polymer feedstocks, avoiding toxic solvents through thermal blending. For laboratory-scale production, hot melt pressing and blow film molding techniques are highlighted for their ability to produce uniform and reproducible films. Uniaxial mechanical testing of dog bone-shaped samples is recommended for rapid performance screening against industry benchmarks while film stability, water absorption, and biodegradation are evaluated under simulated agricultural conditions. Analytical techniques such as thermogravimetric analysis and differential scanning calorimetry are employed to characterize key properties, ensuring that the developed BDMs align with practical and environmental demands.

We present an extrusion-based embedded bioprinting strategy to fabricate dense cellular constructs within bioactive MeHA hydrogels containing human bone microparticles, providing a scalable platform for bone tissue engineering.

Material extrusion-based three-dimensional (3D) printing is a widely used manufacturing technology for fabricating scaffolds and devices in bone tissue engineering (BTE). This technique involves two fundamentally different extrusion approaches: solution-based and melt-based printing. In solution-based printing, a polymer solution is extruded and solidifies via solvent evaporation, whereas in melt-based printing, the polymer is melted at elevated temperatures and solidifies as it cools post-extrusion. Solution-based printing can also be enhanced to generate micro/nano-scale porosity through phase separation by printing the solution into a nonsolvent bath. The choice of the printing method directly affects scaffold properties and the biological response of stem cells. In this study, we selected polycaprolactone (PCL), a biodegradable polymer frequently used in BTE, blended with hydroxyapatite (HA) nanoparticles, a bioceramic known for promoting bone formation, to investigate the effects of the printing approach on scaffold properties and performance in vitro using human mesenchymal stem cells (hMSCs). Our results showed that while both printing methods produced scaffolds with similar strut and overall scaffold dimensions, solvent-based printing resulted in porous struts, higher surface roughness, lower stiffness, and increased crystallinity compared to melt-based printing. Although stem cell viability and proliferation were not significantly influenced by the printing approach, melt-printed scaffolds promoted a more spread morphology and exhibited pronounced vinculin staining. Furthermore, composite scaffolds outperformed their neat counterparts, with melt-printed composite scaffolds significantly enhancing bone formation. This study highlights the critical role of the printing process in determining scaffold properties and performance, providing valuable insights for optimizing scaffold design in BTE.

Biological processes are inherently dynamic, necessitating biomaterial platforms capable of spatiotemporal control over cellular organization and matrix stiffness for accurate study of tissue development, wound healing, and disease. However, most in vitro platforms remain static. In this study, a dynamic biomaterial platform comprising a stiffening hydrogel is introduced and achieved through a stepwise approach of addition followed by light‐mediated crosslinking, integrated with an elastomeric substrate featuring strain‐responsive lamellar surface patterns. Employing this platform, the response of human induced pluripotent stem cell‐derived cardiomyocytes (hIPSC‐CMs) is investigated to dynamic stiffening from healthy to fibrotic tissue stiffness. The results demonstrate that culturing hIPSC‐CMs on physiologically relevant healthy stiffness significantly enhances their function, as evidenced by increased sarcomere fraction, wider sarcomere width, significantly higher connexin‐43 content, and elevated cell beating frequency compared to cells cultured on fibrotic matrix. Conversely, dynamic matrix stiffening negatively impacts hIPSC‐CM function, with earlier stiffening events exerting a more pronounced hindering effect. These findings provide valuable insights into material‐based approaches for addressing existing challenges in hIPSC‐CM maturation and have broader implications across various tissue models, including muscle, tendon, nerve, and cornea, where both cellular alignment and matrix stiffening play pivotal roles in tissue development and regeneration.

Embedded bioprinting is an emerging technology for precise deposition of cell-laden or cell-only bioinks to construct tissue like structures. Bioink is extruded or transferred into a yield stress hydrogel or a microgel support bath allowing print needle motion during printing and providing temporal support for the printed construct. Although this technology has enabled creation of complex tissue structures, it remains a challenge to develop a support bath with user-defined extracellular mimetic cues and their spatial and temporal control. This is crucial to mimic the dynamic nature of the native tissue to better regenerate tissues and organs. To address this, we present a bioprinting approach involving printing of a photocurable viscous support layer and bioprinting of a cell-only or cell-laden bioink within this viscous layer followed by brief exposure to light to partially crosslink the support layer. This approach does not require shear thinning behavior and is suitable for a wide range of photocurable hydrogels to be used as a support. It enables multi-material printing to spatially control support hydrogel heterogeneity including temporal delivery of bioactive cues (e.g. growth factors), and precise patterning of dense multi-cellular structures within these hydrogel supports. Here, dense stem cell aggregates are printed within methacrylated hyaluronic acid-based hydrogels with patterned heterogeneity to spatially modulate human mesenchymal stem cell osteogenesis. This study has significant impactions on creating tissue interfaces (e.g. osteochondral tissue) in which spatial control of extracellular matrix properties for patterned stem cell differentiation is crucial.