Syringe for Injectable Fillers Advisor: Dr. Paul Thompson Client: Dr. Justin Piasecki Therese Rollmann ~ Team Leader Joseph Cabelka ~ Communicator Jennifer Wager ~ BWIG Mark Yarmkovich ~ BSAC

Problem Statement Our goal is to develop a simple syringe device that has a ratchet or incremental mechanism for which a depressed plunger or button will administer a known volume (i.e., 0.1 mL) of an injectable filler such as autologous fat or Sculptra®.

Design Constraints Delivers known increment (50-100 µL) Withstands high temp (121°C) or disposable Volume 1cc or 5 cc syringes Sufficient force to dispel filler Minimize unfamiliar motion

Procedure Motivation Lipoatrophy restoration and lip augmentations Simple procedure ~15 minutes Quick recovery Very few risks involved low risk of allergic reaction, minimal risk of infection Less permanent than plastic surgery (face lift)

Background-Procedure Transfer to a 1 or 5cc syringe Insert needle to dermis or subcutaneous fat layer Inject filler as needle is pulled out Repeat procedure until visual results

Injectable Fillers-Fat Harvested from abdomen 40-50% rate of cell survival expected Cell size = 25-200 µm Viscosity = 3 Pa·s

Injectable Fillers- Sculptra® Composed of synthetic poly-L-lactic acid Stimulates body to produce its own collagen Results last 2 years Side effects: small bumps under skin, other injection-related effects Biocompatible and biodegradable

Suggested Materials Stainless Steel Grade 420 Plastic: Fluoropolymers Temper pt./ Melting pt. 205-650 ºC 260-327ºC Density 7.75 g/cm3 1.5 g/cm3 Cost (per in3) $4.88 $2.41 Elastic Modulus 200 GPa 0.393 GPa

Force Tested expired collagen Minimum force: 4.19N

Current Device - Dispos-A-Ject™ Advantages Dispenses uniform increments Made from surgical stainless steel that is autoclavable. Disadvantages Does not fit 3 or 5cc syringes Bulky Expensive at $375 Many parts

Current Device-Step Meister 1.0 Advantages: Known increment volume Effective in dispensing filler Size and weight Disadvantages: Manual rotation Ergonomics

Design I: Step-Meister 2.0 Similar to Step-Meister 1.0 Use of a torsion spring for rotation Smaller increment sizes (0.1ml0.07ml)

Step-Meister 2.0 Advantages: Eliminates manual rotation Smaller increment sizes Familiar with design Disadvantages: Manufacturing Torsion spring may cause unwanted movement

Design II Button devices advances plunger Bar locks into increment until button is pushed

Design II Advantages: Familiar motion Few parts Accurate and varied increments Disadvantages: Requires practice Large force may hinder function

Design III Squeeze tabs to unlock plunger Push to expel filler

Design III Advantages: Simple mechanism Multiple increments can be expelled Disadvantages: Unfamiliar motion Small parts Manufacturing

Design Matrix 8 6 3 5 4 2 7 20 21 17 Step-Meister 2.0 Design II Design III Many, small parts (10) 8 6 3 Back pressure (5) 5 4 Varied increments (5) 2 Manipulation (10) 7 Total (30) 20 21 17

Future Work Finalize design Research manufacturing possibilities Test force for autologous fat and Sculptra® Construction of prototype Test increment accuracy

References A.D.A.M. Weight Control and Obesity. 11 Oct 2005. http://www.icaa.cc/WCI/graphics/images/en/19267.jpg Byron Medical. 16 September 2005. http://www.byrondirect.com/download/downloads/Catalog/Subsections/Micro-Infiltration.pdf Campbell, N and J Reece. Biology. San Francisco: Pearson, 2005. Encyclopedia of Sports Medicine and Science. 17 September 2005 http://www.sportsci.org/encyc/adipose/adipose.html Dr. Joseph Niamtu. 22 September 2005. Phone Interview Dr. Justin Piasecki. 28 September 2005. Interview Dr. Steve Byrd. 17 September 2005. http://www.drstevebyrd.com/proc_injfillers.asp MSNBC: Fill ‘er up Roundup of Wrinkle Plumpers. 11 Oct 2005. http://www.msnbc.com/modules/cosmetic_surgery/injectables/content.asp?p=all Resitape. 15 February 2006. http://www.resitape.com/en/overview_mgst.html Sculptra. 16 February 2006. http://www.sculptra.com The TexLoc Closet. 15 Febuary 2006. http://www.texloc.com/closet/cl_propertycomparison.htm