The following includes in-depth information about the capabilities of our silicone wristband passive sampling device (PSD) technology. For basic information, check out our Frequently Asked Questions.

A comparison table of the silicone wristband PSD vs. other sampling materials is available in PDF format here. Our analytical methods page provides a full list of chemicals that we are able to detect in our silicone wristband PSDs.

FACT: Conditioned wristbands are a very clean sampler. This provides a good foundation for detecting many chemicals that may be at low concentrations in the environment.

Strengths:

  • Silicone extracts are often easier to analyze than biological samples with few interferences or additional chemical cleanup needed
  • Captures chemicals with a wide range of physicochemical properties
  • Low detection limit possible due to sequestering continuously over long time periods
  • Rugged
  • Ability to re-analyze extracts on new/different methods
  • Because it’s relatively inert, silicone is better to wear against the skin relative to other polymers
  • Pre-deployment preparation of silicone is solvent free

Limitations:

  • Instrumental analysis of liquid extracted silicone may be difficult and time consuming
  • If worn for short time periods in low “pollution” environments will not sequester enough to be seen by analytical methods (sensitivity)
  • At present, ability to analyze without solvent is in method development phase. We are currently validating a thermal method that is solvent free


FACT: The wristband may be transported at ambient conditions, it is not necessary to freeze or transport on ice. 

Strengths:

  • More cost effective shipping
  • Less staff burden


FACT: The wristband is a simple design.

Strengths:

  • Easily worn (children)
  • Power not required
  • Light weight
  • Inexpensive
  • Noninvasive
  • Requires minimal input from study participant while study is ongoing
  • Likely to lead to improved compliance (relative to traditional sampling techniques)
  • Participants are just as likely to wear the wristband to work during the week as they are to wear on the weekend (unlike the actives sampling backpacks which tend to be biased to wearing only while at home)

Limitations:

  • Not real time (the wristband must be sent back to the laboratory). For example, they do not change color when exposed to a chemical. The wristbands are sent to the laboratory where they can be analyzed for over 1,400 chemicals


FACT: Chemicals that may be in sweat or from oral exposures (for example smoking) may be captured by the wristbands.

Strengths:

  • Exposures in the wristband may be consider more comprehensive of your environmental exposures than an air-only personal monitor
  • Fits well with the idea of measuring more of a person’s entire exposure (as in the “exposome” concept)
    • The exposome can be defined as the measure of all the exposures of an individual in a lifetime and how those exposures relate to health.

Limitations:

  • Current methods do not quantify nicotine or distinguish between second-hand or first-hand sources (tobacco)
  • Current risk assessments use defined exposure routes and this approach is not completely synchronized with the exposure measured from the wristbands 


FACT: The wristbands measure an average time-weighted concentration; the average concentration while you wore the wristbands.

Strengths:

  • Captures episodic events
  • Able to detect lower levels of contaminants over time because sampling continuously over time of deployment
  • May be deployed for different time periods depending on study question(s). Can also be used to separate temporal and spatial exposures. For example, one wristband can be worn by an individual while at work, and another worn while at home.

Limitations:

  • Current risk assessments use defined exposure routes and this approach is not completely synchronized with the exposure measured from the wristbands.  


FACT: The wristbands measure volatile and semi-volatile chemicals from the vapor phase.

Strengths:

  • Data may be comparable to that of traditional vapor phase sampling methods (PUF, XAD, diffusive tubes), so comparisons may be made
  • Most chemicals that are traditionally thought of as “only particle-bound” are also present in the vapor phase, albeit at lower levels. Although this is a common misconception, the sensitivity of the wristband allows us to detect and find these chemicals
  • The vapor phase is a biologically relevant fraction

Limitations:

  • Does not include particulate phase, which is a relevant fraction for use in inhalation exposure assessment 


FACT: The wristbands move with people as compared to stationary monitors.

Strengths:

  • The wristband may be more representative of the person’s exposure than a stationary sampler
  • Chemicals, or idiosyncratic uses of chemicals, will likely be able to be distinguished with some sources
  • Fits well with the idea of measuring more of a person’s entire exposure (as in the “exposome” concept)

Limitations:

  • Makes it difficult to interpret point source pollutants, and distinguish between skin or air exposures
  • Without pairing the wristband with a GPS device, it is difficult to link results to any specific point source.  It’s not certain the GPS device would make any difference because of the long-term nature of the exposure and the mobility of the sampler.  Questionnaires can be (and often are) paired with the wristband
  • If temperature is needed in calculations of environmental concentrations, this would have to be estimated based on average outdoor/indoor temperature, and average time spent.  Does not include particulate phase, which is a relevant fraction for use in inhalation exposure assessment


FACT: The wristband extract can be used in bioassays.

Strengths:

  • Also provides a metric to estimate the biological response from the chemical mixture to which the individual was exposed.
  • Extracts allow for use in many bioassays that use 96-well plate formats
  • Morphological and genetic changes seen in bioassays are related directly to an individual's personal environment from the wristband deployment period

Limitations:

  • Small extract volume allows for limited number of exposures in large animal studies (mice, rats)
  • Skin oil background may interfere with biological assays and may have to be separated from extracts

 

Revised: May 3, 2016
Copyright (C) 2016 Oregon State University