Antimicrobial and Bone Growth Responses to Porous Tantalum Coatings - - PowerPoint PPT Presentation

▶
antimicrobial and bone growth responses to porous
SMART_READER_LITE
LIVE PREVIEW

Antimicrobial and Bone Growth Responses to Porous Tantalum Coatings - - PowerPoint PPT Presentation

Mar 10, 2023 33 likes •217 views

Antimicrobial and Bone Growth Responses to Porous Tantalum Coatings David A. Glocker, John L. Greco and Mark Romach Isoflux Incorporated Thomas J. Webster Chair and Professor Department of Chemical Engineering Northeastern University

slide-1
SLIDE 1

Antimicrobial and Bone Growth Responses to Porous Tantalum Coatings

David A. Glocker, John L. Greco and Mark Romach

Isoflux Incorporated

Thomas J. Webster

Chair and Professor Department of Chemical Engineering Northeastern University

Northeastern University

slide-2
SLIDE 2

Outline

  • Introduction and Background
  • Experimental Procedures
  • Tantalum Deposition Conditions and

Coating Properties

  • Antimicrobial and Bone Growth

Measurements

  • Experimental Results
  • Conclusions
slide-3
SLIDE 3

Bacterial Biofilm

The biofilm life cycle.[2]

[1] Center for Biofilm Engineering, Montana State University, P. Dirckx. Used with permission. [2] Cunningham, A. B., et al. Biofilm hypertextbook, Montana State University Center for Biofilm Engineering, 2005. [3] Costerton JW, et al. Science. 1999;284:1318-1322. [4] Costerton JW. Int J Antimicrob. 1999;11:217-221.

  • Hydrated polymeric matrix[3]
  • More tolerant to antibiotic

therapies than planktonic bacteria

  • Easy to form but hard to treat
  • Causes wide-spread

infections[4]

Common sites of biofilm infection.[1]

slide-4
SLIDE 4

Staphylococcus Aureus

  • Numerous infections, such as
  • rthopedic, pimples, impetigo,

pneumonia, endocarditis and sepsis

  • 11 million outpatients, US[5]
  • Medical Devices
  • Catheters
  • Orthopedic prostheses
  • Contact lenses

SEM of Staphylococcus Aureus biofilm[6]

[5] Martinez LR, et al. J Invest Dermatol. 2009; 129(10):2463-2469. [6] E. Swogger, Center for Biofilm Engineering, Montana State University, Bozeman

slide-5
SLIDE 5

Nano-structured Medical Materials

Compared to today’s implants, nano-structured materials possess enhanced:

  • Surface area
  • Radiopacity
  • Catalytic effects
  • Optical properties
  • Mechanical strength
  • Electrical properties
  • Surface properties that may

decrease bacteria function

  • T. J. Webster, in Advances in Chemical Engineering Vol. 27, Academic Press, NY, pgs. 125-166, 2001.

Today’s Implant

6 4 2 6 4 2 6 6 4 2 4 2 6 1.3

Nano-structured Implant

Dimensions in Microns

1.3

slide-6
SLIDE 6

Tantalum Deposition Conditions

Ta Targets Substrates

  • Two Ta inverted cylindrical targets, φ 33 cm by 10 cm

high, separated by 10 cm

  • Total power: 2 kW DC
  • Pressure: 8 mT Kr
  • Deposition Rate: 33 nm/min
  • Thickness: 10 mm
  • Substrates: Ti or PEEK
slide-7
SLIDE 7

Resulting Coating Properties

  • Extreme Zone 1 structure

155 nm 10 µm

slide-8
SLIDE 8

Coating Pore Size Distribution

BET Nitrogen Adsorption Isotherms

slide-9
SLIDE 9

Coating Pore Size Distribution

Cumulative Pore Volume vs. Individual Pore Volume

Cumulative Pore Volume V (µm3/ng) Individual Pore Volume α (µm3)*

0.0 1.0 2.0 3.0 4.0 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01

*Assuming cylindrical pores and a 10 µm thick coating

1

slide-10
SLIDE 10

Coating Pore Size Distribution

Number of Pores vs. Pore Diameter

(1 g ~ 5 X 109 µm2)

1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.E+00 1.E+01 1.E+02 1.E+03

dV/dα (1/ng)

Pore Diameter D (nm)

155 nm

slide-11
SLIDE 11

In vivo Infection Model

 To determine the ability of bone to grow on the proposed

materials in the presence of bacteria:

 Some samples were used as-is while some were

soaked in antibiotics

 Samples were then inoculated with 105 Staph.

epidermidis colony forming units and implanted into rat calvial defects

 After 1 or 4 weeks, samples with juxtaposed bone

were removed and tested for bone push-out strength

slide-12
SLIDE 12

Improved Push-Out Strength for Coated Titanium (1 Week)

Y axis = push-out strength in Mpa. Data = mean ± SEM; N = 3.

slide-13
SLIDE 13

Improved Push-Out Strength for Coated Titanium (4 Weeks)

Y axis = push-out strength in Mpa. Data = mean ± SEM; N = 3.

slide-14
SLIDE 14

Improved Push-Out Strength for Coated PEEK (1 Week)

Y axis = push-out strength in MPa. Data = mean ± SEM; N = 3. Isoflux TA coating p < 0.0004 compared to PEEK without coating.

slide-15
SLIDE 15

Improved Push-Out Strength for Coated PEEK (4 Weeks)

Y axis = push-out strength in MPa. Data = mean ± SEM; N = 3. Isoflux TA coating p < 0.0004 compared to PEEK without coating.

slide-16
SLIDE 16

C y t

  • s

k e l e t

  • n

Integrin α β

Ca2+

Fibronectin RGD Cell Substrate C y t

  • s

k e l e t

  • n

Integrin α β

Ca2+

Fibronectin RGD Cell Substrate

Increasing Bone Growth and Decreasing Bacteria Growth on Nanofeatured Materials

Create nano-surfaces to increase surface energy

  • n materials which

increases bone growth

slide-17
SLIDE 17

Conclusions

 Nanoporous tantalum coated materials

improved bone growth in the presence of bacteria to significantly improve push-out strength.

 Future studies should determine the exact

mechanism of increased bone growth and decreased bacteria growth on the proposed materials.

slide-18
SLIDE 18