Publications by authors named "Tamara Lambert"

3 Publications

  • Page 1 of 1

Platelet heterogeneity enhances blood clot volumetric contraction: An example of asynchrono-mechanical amplification.

Biomaterials 2021 07 23;274:120828. Epub 2021 Apr 23.

George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, Atlanta, GA, 30332-0405, USA. Electronic address:

Physiological processes such as blood clotting and wound healing as well as pathologies such as fibroses and musculoskeletal contractures, all involve biological materials composed of a contracting cellular population within a fibrous matrix, yet how the microscale interactions among the cells and the matrix lead to the resultant emergent behavior at the macroscale tissue level remains poorly understood. Platelets, the anucleate cell fragments that do not divide nor synthesize extracellular matrix, represent an ideal model to study such systems. During blood clot contraction, microscopic platelets actively pull fibers to shrink the macroscale clot to less than 10% of its initial volume. We discovered that platelets utilize a new emergent behavior, asynchrono-mechanical amplification, to enhanced volumetric material contraction and to magnify contractile forces. This behavior is triggered by the heterogeneity in the timing of a population of actuators. This result indicates that cell heterogeneity, often attributed to stochastic cell-to-cell variability, can carry an essential biophysical function, thereby highlighting the importance of considering 4 dimensions (space + time) in cell-matrix biomaterials. This concept of amplification via heterogeneity can be harnessed to increase mechanical efficiency in diverse systems including implantable biomaterials, swarm robotics, and active polymer composites.
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July 2021

Getting a good view: imaging of platelets under flow.

Platelets 2020 Jul 28;31(5):570-579. Epub 2020 Feb 28.

The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, GA, USA.

As the anucleate cells responsible for hemostasis and thrombosis, platelets are exposed to a myriad of biophysical and biochemical stimuli within vasculature and heterogeneous blood clots. Highly controlled, reductionist imaging studies have been instrumental in providing a detailed and quantitative understanding of platelet biology and behavior, and have helped elucidate some surprising functions of platelets. In this review, we highlight the tools and approaches that enable visualization of platelets in conjunction with precise control over the local biofluidic and biochemical microenvironment. We also discuss next generation tools that add further control over microenvironment cell stiffness or enable visualization of the interactions between platelets and endothelial cells. Throughout the review, we include pragmatic knowledge on imaging systems, experimental conditions, and approaches that have proved to be useful to our imaging studies of platelets under flow.
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July 2020

Prolonged Release of Bioactive Model Proteins from Anionic Microgels Fabricated with a New Microemulsion Approach.

Pharm Res 2016 Apr 30;33(4):879-92. Epub 2015 Nov 30.

Meinig School of Biomedical Engineering, Cornell University, 147 Weill Hall, Ithaca, New York, 14853, USA.

Purpose: Therapeutic proteins have become an integral part of health care. However, their controlled delivery remains a challenge. Protein function depends on a delicate three dimensional structure, which can be damaged during the fabrication of controlled release systems. This study presents a microgel-based controlled release system capable of high loading efficiencies, prolonged release and retention of protein function.

Methods: A new DMSO/Pluronic microemulsion served as a reaction template for the crosslinking of poly(acrylic acid) and oligo (ethylene glycol) to form microgels. Poly(acylic acid) molecular weights and microgel crosslinking densities were altered to make a series of microgels. Microgel capacity to capture and retain proteins of different sizes and isoelectric points, to control their release rate (over ~30 days) and to maintain the biofunctionality of the released proteins were evaluated.

Results: Microgels of different sizes and morphologies were synthesized. Loading efficiencies of 100% were achieved with lysozyme in all formulations. The loading efficiency of all other proteins was formulation dependent. Release of lysozyme was achieved for up to 30 days and the released lysozyme retained over 90% of its activity.

Conclusions: High loading efficiencies and prolonged release of different proteins was achieved. Furthermore, lysozyme's functionality remained uncompromised after encapsulation and release. This work begins to lay the foundation for a broad platform for the delivery of therapeutic proteins.
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April 2016