Powerpoint template for scientific posters Swarthmore College

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Dextran- Hydrogel Rheology and Dextranase Enzyme
Activity P. Crockett, M. Lee, R. Composto
Drexel RET-NANO Program, Department of Material
Science and Engineering

• Conclusions
• Dextran-GMA Hydrogels were analyzed at various
  concentrations using rheometry. Hydrogel
  compliance increased linearly with concentration.
• A color change assay was produced using optimal
  Maltose concentrations.
• Enzyme activity was found to degrade 2 Dextran
  at close to suppliers specifications.
• Dextranase was found to have negligible activity
  difference at pH 6 and pH 7.
• Enzyme activity proved to be significantly
  enhanced by activator at pH 6 but lost it
  effectiveness at pH 7.

• Results
• The first results of our research shows that
  Dextran-GMA compliance increases linearly with
  concentration. The compliance force went from
  very small at 80 mg/ml to very high and 200
  mg/ml.
• Second, we calibrated the Maltose color assay so
  we could quantify Dextranase activity. Maltose is
  the product of Dextranases degradation of
  Dextran.
• Third, we found that Dextranase has near
  equivalent activity at both pH 6 and PH 7.
• Fourth, we concluded that the Dextranase
  activator works well at pH 6 but loses its
  effectiveness at pH 7.

Fig. 6. Boiling enzyme mixture to produce color
change based on Maltose sugar production.

• Introduction
• Hydrogels are used for a wide array of
  biomaterials applications, such as contact
  lenses, drug delivery vehicles, and tissue
  adhesives.
• The favorable properties of Hydrogels include
  Hydrophilicity, elasticity, and can be modulated
  chemically.
• Dextrans are carbohydrate polymers with
  properties that mimic biological sugars found on
  tissue surfaces.
• Dextran coated surfaces can be used to grow up
  cells to later be cleaved as a sheet via
  Dextranase..

Fig. 7. Absorbance produced by various Maltose
standards.

Fig. 4. Dextran-GMA Hydrogel compliance at
various concentrations.

• Materials and Methods
• The first part of our research focused on how
  Dextran-GMA Hydrogel compliance varies with
  concentration.
• The second part of our research was focused on
  the effect of Dextranase on our Dextran.
• Once the optimal pH and temperature are found, we
  hope to compare and contrast Dextranase activity
  with Dextran and Dextran-GMA Hydrogel.

Fig. 8. Absorbance produced by various enzyme
concentrations.
References 1. Influence of the degradation
mechanism of Hydrogels on their elastic and
swelling properties during degradation Meyvis,
T.K.L. (Ghent Univ) De Smedt, S.C. Demeester,
J. Hennink, W.E. Source Macromolecules, v 33,
n 13, Jun, 2000, p 4717-4725 2.Swelling pressure
of Hydrogels that degrade through different
mechanisms Stubbe, B.G. (Lab. Gen. Biochem. and
Phys. Pharm., Department of Pharmaceutics, Ghent
University) Hennink, W.E. De Smedt, S.C.
Demeester, J. Source Macromolecules, v 37, n
23, Nov 16, 2004, p 8739-8744 3.Enzymatic
degradation of cross-linked Dextrans Franssen, O.
(Universiteit Utrecht) van Ooijen, R.D. de
Boer, D. Maes, R.A.A. Hennink, W.E. Source
Macromolecules, v 32, n 9, May, 1999, p
2896-2902
Fig.9. Comparison of Dextranase activity at Ph 6
with and without activator.
Fig. 2. Rheometer used to find Dextran compliance.
Fig. 5. Cuvettes showing the color difference
resulting from varying Dextranase concentration.
Acknowledgments I would like to thank Dr.
Composto and Dr. Boettiger for allowing me the
opportunity to utilize their laboratory
resources. Dr. Mark Lee for being an excellent
teacher and providing me with an exciting project
to work on. Drexel RET-NANO for allowing this
teacher to the opportunity to bring cutting edge
research back to my students.
Fig. 10. Comparison of enzyme activity at pH 6
and Ph 7 with and without activator.
Fig. 3. Loading Dextran samples into cuvetts for
spectrometer analysis.