New Publication: Precision Engineering of Chondrocyte Microenvironments: Investigating the Optimal Reaction Conditions for Type B Gelatin Methacrylate Hydrogel Matrix for TC28a2 CellsNew Publication:

The newest publication from our lab is now available online!

This research was led by Qichan and is co-authored by Marc Anthony.


Gelatin methacrylate (GelMA) is a photocrosslinkable biomaterial that has gained widespread use in tissue engineering due to its favorable biological attributes and customizable physical and mechanical traits. While GelMA is compatible with various cell types, distinct cellular responses are observed within GelMA hydrogels. As such, tailoring hydrogels for specific applications has become imperative. Thus, our objective was to develop GelMA hydrogels tailored to enhance cell viability specifically for TC28a2 chondrocytes in a three-dimensional (3D) cell culture setting. We investigated GelMA synthesis using PBS and 0.25M CB buffer, analyzed the mechanical and physical traits of GelMA hydrogels, and evaluated how varying GelMA crosslinking conditions (GelMA concentration, photoinitiator concentration, and UV exposure time) affected the viability of TC28a2 chondrocytes. The results revealed that GelMA synthesis using 0.25M CB buffer led to a greater degree of methacrylation compared to PBS buffer, and the LAP photoinitiator demonstrated superior efficacy for GelMA gelation compared to Irgacure 2959. Additionally, the stiffness, porosity, and swelling degree of GelMA hydrogels were predominantly affected by GelMA concentration, while cell viability was impacted by all crosslinking conditions, decreasing notably with increasing GelMA concentration, photoinitiator concentration, and UV exposure time. This study facilitated the optimization of crosslinking conditions to enhance cell viability within GelMA hydrogels, a critical aspect for diverse biomedical applications.

Do you want to read more? The full publication can be found here:

Q. Hu, M. A. Torres, H. Pan, S. L. Williams and M. Ecker, M. Precision Engineering of Chondrocyte Microenvironments: Investigating the Optimal Reaction Conditions for Type B Gelatin Methacrylate Hydrogel Matrix for TC28a2 Cells. J. Funct. Biomater., 2024, 15.

Celebrating a Milestone: Chandani, Our First PhD Graduate!

We are thrilled to share a momentous achievement in the history of our lab – the graduation of Chandani Chitrakar, our first-ever PhD student! Chandani has been an integral part of our research community, and her dedication, passion, and hard work have left an indelible mark on our lab.

The Journey:

Chandani embarked on her doctoral journey with us in 2019, bringing not only her academic prowess but also a contagious enthusiasm for pushing the boundaries of scientific exploration. Throughout the years, she has been a beacon of inspiration for her peers and an invaluable asset to our research endeavors.

Research Contributions:

Chandani’s research has been nothing short of groundbreaking. Her innovative work on the DEVELOPMENT AND CHARACTERIZATION OF COMPLIANT BIOELECTRONIC DEVICES FOR GASTROINTESTINAL STIMULATION has not only expanded our understanding of smart polymers but has also garnered recognition within the scientific community. Her contributions have been instrumental in shaping the direction of our lab’s research and will undoubtedly influence the field for years to come.

Collaboration and Leadership:

Beyond her individual achievements, Chandani has been a collaborative force within our lab. She has fostered a culture of teamwork, inspiring fellow students and researchers to work together toward common goals. Her leadership qualities have been evident in several publications, where she spearheaded the manuscript preparation.

Chandani’s Impact:

As Chandani walks across the stage to receive her well-deserved doctoral hood, we reflect on the lasting impact she leaves on our lab. Her resilience, intellectual curiosity, and commitment to excellence have set a high standard for future graduate students to aspire to.

Looking Ahead:

Chandani’s success is a testament to the vibrant research environment we strive to cultivate in our lab. As we celebrate this milestone, we eagerly anticipate the continued success of our graduate students, each contributing to the rich tapestry of discoveries that define our research community.

Join us in extending heartfelt congratulations to Chandani for her remarkable achievement! As she takes the next steps in her career, we are confident that her journey will continue to inspire and shape the future of scientific inquiry.

New Publication: Multifaceted Shape Memory Polymer Technology for Biomedical Application: Combining Self-Softening and Stretchability Properties

The newest publication from our lab is now online available!

This research was led by Chandani and is co-authored by Marc Anthony and Qichan.


Thiol-ene polymers are a promising class of biomaterials with a wide range of potential applications, including organs-on-a-chip, microfluidics, drug delivery, and wound healing. These polymers offer flexibility, softening, and shape memory properties. However, they often lack the inherent stretchability required for wearable or implantable devices. This study investigated the incorporation of di-acrylate chain extenders to improve the stretchability and conformability of those flexible thiol-ene polymers. Thiol-ene/acrylate polymers were synthesized using 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATATO), Trimethylolpropanetris (3-mercaptopropionate) (TMTMP), and Polyethylene Glycol Diacrylate (PEGDA) with different molecular weights (Mn 250 and Mn 575). Fourier Transform Infrared (FTIR) spectroscopy confirmed the complete reaction among the monomers. Uniaxial tensile testing demonstrated the softening and stretching capability of the polymers. The Young’s Modulus dropped from 1.12 GPa to 260 MPa upon adding 5 wt% PEGDA 575, indicating that the polymer softened. The Young’s Modulus was further reduced to 15 MPa under physiologic conditions. The fracture strain, a measure of stretchability, increased from 55% to 92% with the addition of 5 wt% PEGDA 575. A thermomechanical analysis further confirmed that PEGDA could be used to tune the polymer’s glass transition temperature (Tg). Moreover, our polymer exhibited shape memory properties. Our results suggested that thiol-ene/acrylate polymers are a promising new class of materials for biomedical applications requiring flexibility, stretchability, and shape memory properties.

Do you want to read more? The full publication can be found here:

C. Chitrakar, M.A. Torres, P.E. Rocha-Flores, Q. Hu, M. Ecker, Multifaceted Shape Memory Polymer Technology for Biomedical Application: Combining Self-Softening and Stretchability Properties. Polymers202315, 4226.

We are hiring

Research Assistant/Ph.D. Position in Polymeric Biomaterials

The Smart Polymers for Biomedical Applications Lab (aka the Ecker Lab) in the Department of Biomedical Engineering at the University of North Texas has an open Ph.D. position for Fall 2023.

Project Background

The Ecker Lab is conducting research at the intersection of polymer science and biomedical engineering. Our Team is quite diverse and has expertise in Chemistry, Materials Science, Engineering, and Biology. We combine all those fields to develop next-generation biomedical devices based on smart polymeric materials. These materials consist of shape memory polymers that are responsive to bodily conditions and are mechanically adaptive to comply with a tissue. Some of our custom polymers are also biodegradable. Additionally, we make sure that our novel materials are biocompatible.

Job Description

We are looking for an enthusiastic and motivated individual to investigate the structure-property relationship of shape memory polymers for biomedical applications. The goal of this NSF-funded project is to elucidate the underlying mechanism of the plasticization-induced shape memory effect of thiol-ene-based polymers. The model application for this material will be a heat shrink tubing that can shrink at bodily conditions (37° C and simulated body fluids) and can be used to seal colonic anastomosis.

This project will be based in Melanie Eckers Smart Polymers for Biomedical Applications Lab at UNT.

Your Profile

  • You hold a Master’s degree in materials science, polymer science, chemistry, or a related field.
  • Experience in polymer material processing (required)
  • Experience with shape memory polymers (beneficial)
  • Experience with mechanical and thermomechanical characterization (beneficial)
  • Proficiency in oral and written English (required)
  • Enthusiastic, creative, and self-motivated (required)

We Offer

We offer a research assistant position for up to five years (contingent on yearly positive evaluations). You will be working in a dynamic and interdisciplinary work environment in the Ecker lab, which is part of the Department of Biomedical Engineering. Our lab is highly diverse, and we value members from all personal backgrounds.

Our department is committed to educating and creating well-rounded, knowledgeable biomedical engineers passionate about improving the quality of life for people in Texas, the United States, and the world. Our Ph.D. program offers two tracks: a traditional research track that will help you progress toward your academic career goal and a one-of-a-kind healthcare start-up management track in collaboration with the G. Brint Ryan College of Business.

What is the University like?

The University of North Texas is a student-centered public research university with over 40,000 students. A Carnegie-ranked Tier One public research university, UNT is one of the nation’s most diverse universities. UNT has been designated as both a Minority Serving Institution and Hispanic Serving Institution and stands committed to equity, diversity, and inclusion in its pursuit of academic excellence.

With 7.5 million people and two international airports, DFW is the fourth-largest metro area in the United States. DFW is racially, ethnically, religiously, and culturally rich and maintains a long-standing commitment to the arts exemplified by local attractions such as the Dallas Arts District and the Fort Worth Cultural District. UNT’s proximity to these major metropolitan centers ensures that our new colleague will be able to access a wide range of activities and cultural experiences.

UNT is located in Denton, Texas, a growing city with a small-town feel and a thriving arts and music scene centered on its downtown Square and is connected by highways and light rail to the major transportation hubs and big-city attractions of Dallas and Fort Worth, about 40 miles away. Want to know more about why you should consider coming to Denton? Check out Discover Denton.

Curious? So are we.

We look forward to receiving your email application, including:

  • a letter of motivation,
  • a brief statement of research interests,
  • copies of Bachelor’s and Master’s degree transcripts,
  • a CV,
  • the names and contact information of at least two academic referees.

To apply for this position, please contact Dr. Melanie Ecker at

Dr. Ecker received NSF CAREER Award

We are excited to share that Dr. Ecker has received the prestigious National Science Foundation (NSF) CAREER award to conduct research on Shape Memory Polymers as Biomaterial.

CAREER: The Faculty Early Career Development (CAREER) Program is a Foundation-wide activity that offers the National Science Foundation’s most prestigious awards in support of early-career faculty who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization. Activities pursued by early-career faculty should build a firm foundation for a lifetime of leadership in integrating education and research.

NSF Website

This CAREER project aims to elucidate the underlying mechanism of the plasticization-induced shape memory effect of thiol-ene based polymers. The model application for this material will be a heat shrink tubing that can shrink at bodily conditions (37° C and simulated body fluids) and can be used to seal colonic anastomosis. The specific three aims are to (1) Systematically investigate the effect of crosslink-density and chain extender length on the plasticization-induced shape memory effect of thiol-ene based polymers. Mechanical and thermomechanical measurements inside simulated body fluids will be used to assess shape memory properties and structure-property relationships. (2) Understand the relationship between material thickness, degree of shape-programming, and radial recovery forces of tube-shaped SMPs to determine optimal design parameters for sufficient shape recovery using the heat shrink tube model. (3) Demonstrate the functionality of a biomedical heat shrink tube that utilizes the plasticization-induced shape recovery through an ex vivo colon anastomosis model and quantify mechanical and sealing properties. The proposed research will advance science by filling the gap in the structure-property relationship of thiol-ene based SMPs that utilize plasticization for their shape recovery, which is essential for designing future devices. In addition, this innovative biomaterial will allow the broader research community to develop novel biomedical devices tailored to specific tissues and applications. Educational and outreach activities will be implemented to raise excitement, awareness, and interest in the emerging field of smart polymeric biomaterials. These will include a gender- and ethnicity-matched mentor-mentee program, training students from underrepresented groups in the PI’s laboratory, incorporating research discoveries into coursework, and communicating research to the general public at local science slam events.

Here is a link to the full abstract

New Publication: Thermo/hydration responsive shape memory polymers with enhanced hydrophilicity for biomedical applicationsNew Publication:

A collaborative project with the Voit Group from UT Dallas. Congratulations, Qichan, for this contribution!


Thiol-ene/acrylate shape memory polymers (SMPs) have sufficient stiffness for facile insertion and precision placement and soften after exposure to physiological conditions to reduce the mechanical mismatch with body tissue. As a result, they have demonstrated excellent potential as substrates for various flexible bioelectronic devices, such as cochlear implants, nerve cuffs, cortical probes, plexus blankets, and spinal cord stimulators. To enhance the shape recovery properties and softening effect of SMPs under physiological conditions, we designed and implemented a new class of SMPs as bioelectronics substrates. In detail, we introduced dopamine acrylamide (DAc) as a hydrophilic monomer into a current thiol-ene polymer network. Dry and soaked dynamic mechanical analyses were performed to evaluate the thermomechanical properties, softening kinetics under wet conditions, and shape recovery properties. Modification of SMPs by DAc provided an improved softening effect and shape recovery speed under physiological conditions. Here, we report a new strategy for designing SMPs with enhanced shape recovery properties and lower moduli than previously reported SMPs under physiological conditions without sacrificing stiffness at room temperature by introducing a hydrophilic monomer.

Do you want to read more? The full publication can be found here:

New Publication: Recyclable, Biobased Photoresins for 3D Printing Through Dynamic Imine Exchange

This work was led by the Smaldone Group from UT Dallas. Lauren and Chandani completed some of the thermomechanical characterizations.


Transimination reactions are highly effective dynamic covalent reactions to enable reprocessability in thermosets, as they can undergo exchange without the need for catalysts, by exposing the materials to external stimuli such as heat. In this work, a series of five biobased vanillin-derived resin formulations consisting of vanillin acrylate with vanillin methacrylate-functionalized Jeffamines were synthesized and 3D-printed using digital light projection (DLP). The resulting thermosets displayed a range of mechanical properties (Young’s modulus 2.05–332 MPa), which allow for an array of applications. The materials we obtained have self-healing abilities, which were characterized by scratch healing tests. Additionally, dynamic transimination reactions enable these thermosets to be reprocessed when thermally treated above their glass transition temperatures under high pressures using a hot press. Due to the simple synthetic procedures and the readily available commercial Jeffamines, these materials will aid in promoting a shift to materials with predominantly biobased content and help drift away from polymers made from non-renewable resources.

Do you want to read more? The full publication can be found here:

New publication: Flexible and Stretchable Bioelectronics

The first publication of 2022 is now published and online available! Congratulations to Chandani, Eric, and Lauren for their great review paper on stretchable and flexible bioelectronics!


Medical science technology has improved tremendously over the decades with the invention of robotic surgery, gene editing, immune therapy, etc. However, scientists are now recognizing the significance of ‘biological circuits’ i.e., bodily innate electrical systems for the healthy functioning of the body or for any disease conditions. Therefore, the current trend in the medical field is to understand the role of these biological circuits and exploit their advantages for therapeutic purposes. Bioelectronics, devised with these aims, work by resetting, stimulating, or blocking the electrical pathways. Bioelectronics are also used to monitor the biological cues to assess the homeostasis of the body. In a way, they bridge the gap between drug-based interventions and medical devices. With this in mind, scientists are now working towards developing flexible and stretchable miniaturized bioelectronics that can easily conform to the tissue topology, are non-toxic, elicit no immune reaction, and address the issues that drugs are unable to solve. Since the bioelectronic devices that come in contact with the body or body organs need to establish an unobstructed interface with the respective site, it is crucial that those bioelectronics are not only flexible but also stretchable for constant monitoring of the biological signals. Understanding the challenges of fabricating soft stretchable devices, we review several flexible and stretchable materials used as substrate, stretchable electrical conduits and encapsulation, design modifications for stretchability, fabrication techniques, methods of signal transmission and monitoring, and the power sources for these stretchable bioelectronics. Ultimately, these bioelectronic devices can be used for wide range of applications from skin bioelectronics and biosensing devices, to neural implants for diagnostic or therapeutic purposes.

Do you want to read more? The full publication can be found here.