Publications - DO NOT EDIT
http://hdl.handle.net/10106/24354
2024-03-28T19:56:38ZNovel Polymeric Scaffolds Using Protein Microbubbles as Porogen and Growth Factor Carriers
http://hdl.handle.net/10106/24541
Novel Polymeric Scaffolds Using Protein Microbubbles as Porogen and Growth Factor Carriers
Nair, Ashwin; Thevenot, Paul Todd; Dey, Jagannath; Shen, Jinhui; Sun, Man-Wu; Yang, Jian; Tang, Liping
**Please note that the full text is embargoed** ABSTRACT: Polymeric tissue engineering scaffolds prepared by conventional techniques like salt leaching and phase separation are greatly limited by their poor biomolecule-delivery abilities. Conventional methods of incorporation of
various growth factors, proteins, and=or peptides on or in scaffold materials via different crosslinking and
conjugation techniques are often tedious and may affect scaffold’s physical, chemical, and mechanical properties.
To overcome such deficiencies, a novel two-step porous scaffold fabrication procedure has been created in which
bovine serum albumin microbubbles (henceforth MB) were used as porogen and growth factor carriers. Polymer
solution mixed with MB was phase separated and then lyophilized to create porous scaffold. MB scaffold
triggered substantially lesser inflammatory responses than salt-leached and conventional phase-separated
scaffolds in vivo. Most importantly, the same technique was used to produce insulin-like growth factor-1 (IGF-1)–
eluting porous scaffolds, simply by incorporating IGF-1–loaded MB (MB-IGF-1) with polymer solution before
phase separation. In vitro such MB-IGF-1 scaffolds were able to promote cell growth to a much greater extent
than scaffold soaked in IGF-1, confirming the bioactivity of the released IGF-1. Further, such MB-IGF-1 scaffolds
elicited IGF-1–specific collagen production in the surrounding tissue in vivo. This novel growth factor–eluting
scaffold fabrication procedure can be used to deliver a range of single or combination of bioactive biomolecules
to substantially promote cell growth and function in degradable scaffold.
2010-01-01T00:00:00ZReal-time detection of implant-associated neutrophil responses using a formyl peptide
receptor-targeting NIR nanoprobe
http://hdl.handle.net/10106/24540
Real-time detection of implant-associated neutrophil responses using a formyl peptide
receptor-targeting NIR nanoprobe
Zhou, Jun; Yi-Ting, Tsai; Weng, Hong; Tang, Ewin N.; Nair, Ashwin; Digant, Dave P.; Tang, Liping
Neutrophils play an important role in implant-mediated inflammation and
infection. Unfortunately, current methods which monitor neutrophil activity, including enzyme
measurements and histological evaluation, require many animals and cannot be used to accurately
depict the dynamic cellular responses. To understand the neutrophil interactions around
implant-mediated inflammation and infection it is critical to develop methods which can monitor
in vivo cellular activity in real time. In this study, formyl peptide receptor (FPR)-targeting nearinfrared nanoprobes were fabricated. This was accomplished by conjugating near-infrared dye
with specific peptides having a high affinity to the FPRs present on activated neutrophils. The
ability of FPR-targeting nanoprobes to detect and quantify activated neutrophils was assessed
both in vitro and in vivo. As expected, FPR-targeting nanoprobes preferentially accumulated on
activated neutrophils in vitro. Following transplantation, FPR-targeting nanoprobes preferentially accumulated at the biomaterial implantation site. Equally important, a strong relationship
was observed between the extent of fluorescence intensity in vivo and the number of recruited
neutrophils at the implantation site. Furthermore, FPR-targeting nanoprobes may be used to
detect and quantify the number of neutrophils responding to a catheter-associated infection.
The results show that FPR-targeting nanoprobes may serve as a powerful tool to monitor and
measure the extent of neutrophil responses to biomaterial implants in vivo.
2012-04-19T00:00:00ZMethod to Analyze Three-Dimensional Cell Distribution and Infiltration in Degradable Scaffolds
http://hdl.handle.net/10106/24539
Method to Analyze Three-Dimensional Cell Distribution and Infiltration in Degradable Scaffolds
Thevenot, Paul Todd; Nair, Ashwin; Dey, Jagannath; Yang, Jian; Tang, Liping
**Please note that the full text is embargoed** ABSTRACT: Effective cell seeding throughout the tissue scaffold often determines the success of tissue-engineering products,
although most current methods focus on determining the total number, not the distribution, of the cells associated
with tissue-engineering constructs. The purpose of this investigation was to establish a quick, convenient, and
efficient method to quantify cell survival, distribution, and infiltration into degradable scaffolds using a combination of fluorescence cell staining and cryosectioning techniques. After cell seeding and culture for different
periods of time, seeded scaffolds were stained with a live cell dye and then cryosectioned. Cryosectioned scaffolds
were then recompiled into a three-dimensional (3D) image to visualize cell behavior after seeding. To test the
effectiveness of this imaging method, four common seeding methods, including static surface seeding, cell injection, orbital shaker seeding, and centrifuge seeding, were investigated for their seeding efficacy. Using this new
method, we were able to visualize the benefits and drawbacks of each seeding method with regard to the cell
behavior in 3D within the scaffolds. This method is likely to provide useful information to assist the development
of novel materials or cell-seeding methods for producing full-thickness tissue grafts.
2008-01-01T00:00:00ZIntraocular Pressure Changes: An Important Determinant
of the Biocompatibility of Intravitreous Implants
http://hdl.handle.net/10106/24538
Intraocular Pressure Changes: An Important Determinant
of the Biocompatibility of Intravitreous Implants
Nair, Ashwin; Zou, Ling; Weng, Hong; Tsai, Yi-Ting; Hu, Zhibing; Tang, Liping