Measurement systems and methods

Abstract

A measurement system including a staging unit including a substrate having piezoelectric properties and a conductive electrode formed on the substrate, the conductive electrode including an area adapted to receive a sample, and an oscillator coupled to the conductive electrode. A method including in a tissue sample having a mass of less than about one microgram and that exerts a high osmotic pressure, calculating an osmotic pressure value for the tissue sample from a plurality of measurements of changes in the mass due to swelling.

1 . A measurement system comprising: 
 a staging unit comprising: 
 a substrate having piezoelectric properties; and  
 a conductive electrode formed on the substrate, the conductive electrode including an area adapted to receive a sample; and  
   an oscillator coupled to the conductive electrode.    
   
   
       2 . The measurement system of  claim 1 , wherein the substrate comprises a quartz crystal.  
   
   
       3 . The measurement system of  claim 2 , wherein the conductive electrode comprises a gold alloy.  
   
   
       4 . The measurement system of  claim 3 , wherein the area of the conductive electrode adapted to receive the sample is adapted to receive a soft tissue sample.  
   
   
       5 . The measurement system of  claim 3 , wherein the area of the conductive electrode adapted to receive the sample is adapted to receive a soft tissue sample comprising a mass of less than about a microgram.  
   
   
       6 . A measurement system comprising: 
 a staging unit comprising: 
 a substrate having piezoelectric properties and an area of the substrate adapted to receive a sample; and  
 a conductive electrode formed on the substrate; and  
   an oscillator coupled to the conductive electrode.    
   
   
       7 . The measurement system of  claim 6 , wherein the substrate comprises a piezoelectric ceramic.  
   
   
       8 . The measurement system of  claim 7 , wherein the conductive electrode comprises a silver alloy.  
   
   
       9 . The measurement system of  claim 7 , wherein the area of the substrate adapted to receive the sample is adapted to receive a soft tissue sample.  
   
   
       10 . A measurement system comprising: 
 an enclosure having a humidity level that is controllable;    a staging unit mountable within the enclosure, the staging unit comprising: 
 a substrate having piezoelectric properties;  
 a conductive electrode formed on the substrate; and  
 a monolayer formed on the conductive electrode and adapted to receive a sample; and  
   a variable oscillator coupled to the conductive electrode.    
   
   
       11 . The measurement system of  claim 10 , wherein the enclosure comprises a substantially sealed enclosure.  
   
   
       12 . The measurement system of  claim 11 , wherein the substrate comprises a ceramic.  
   
   
       13 . The measurement system of  claim 12 , wherein the monolayer comprises a hydrophilic material.  
   
   
       14 . The measurement system of  claim 13 , wherein the variable oscillator is adapted to generate a range of frequencies that includes one or more resonant frequencies of the substrate.  
   
   
       15 . A staging unit comprising: 
 a substrate having piezoelectric properties; and    a conductive electrode formed on the substrate, the conductive electrode adapted to receive a tissue sample.    
   
   
       16 . The staging unit of  claim 15 , wherein the substrate comprises a quartz crystal.  
   
   
       17 . The staging unit of  claim 15 , wherein the conductive electrode comprises a gold alloy.  
   
   
       18 . The staging unit of  claim 15 , wherein the conductive electrode adapted to receive the tissue sample is adapted to receive a tissue sample having a thickness of between about 0.2 microns and about 500 microns.  
   
   
       19 . A staging unit comprising: 
 a substrate having piezoelectric properties;    a conductive electrode formed on the substrate; and    a monolayer formed on the conductive electrode and adapted to receive a sample.    
   
   
       20 . The staging unit of  claim 19 , wherein the conductive electrode adapted to receive the sample is adapted to receive a tissue sample.  
   
   
       21 . The staging unit of  claim 19 , wherein the conductive electrode adapted to receive the sample is adapted to receive a soft tissue sample.  
   
   
       22 . The staging unit of  claim 19 , wherein the conductive electrode adapted to receive the sample is adapted to receive a cartilage sample having a thickness of between about 10 microns and about 20 microns.  
   
   
       23 . The staging unit of  claim 19 , wherein the conductive electrode is adapted to receive a substantially liquid sample.  
   
   
       24 . The staging unit of  claim 19 , wherein the conductive electrode is structured for receiving a thin slice of soft tissue.  
   
   
       25 . The staging unit of  claim 19 , wherein the monolayer comprises a hydrophobic material.  
   
   
       26 . The staging unit of  claim 19 , wherein the monolayer comprises a hydrophilic material.  
   
   
       27 . A method comprising: 
 in a tissue sample having a mass of less than about one microgram, measuring changes on the order of about one nanogram in the mass due to swelling.    
   
   
       28 . The method of  claim 27 , further comprising: 
 exposing the tissue sample to a plurality of different humidity environments and measuring the mass of the tissue sample after each exposure.    
   
   
       29 . The method of  claim 28 , further comprising: 
 calculating an osmotic pressure for the tissue sample.    
   
   
       30 . A method comprising: 
 in a tissue sample having a mass of less than about one microgram and that exerts a high osmotic pressure, calculating an osmotic pressure value for the tissue sample from a plurality of measurements of changes in the mass due to swelling.    
   
   
       31 . A method comprising: 
 attaching a sample having a mass to a conductive electrode formed on a substrate;    serially placing the substrate in a plurality of enclosures, each of the plurality of enclosures having a different humidity level; and    measuring the mass of the sample in each of the plurality of enclosures to form a plurality of measurement values.    
   
   
       32 . The method of  claim 31 , further comprising calculating an osmotic pressure value for the sample from the plurality of measurement values.  
   
   
       33 . The method of  claim 32 , wherein measuring the mass of the sample in each of the plurality of enclosures comprises: 
 identifying a frequency at which the substrate is resonant.    
   
   
       34 . The method of  claim 33 , wherein identifying the frequency at which the substrate is resonant comprises: 
 applying one or more signals of different frequencies to the conductive electrode; and    identifying one of the one or more frequencies as a resonant frequency.    
   
   
       35 . The method of  claim 31 , wherein attaching the sample having the mass to the conductive electrode comprises: 
 forming a monolayer on the conductive electrode; and    forming the sample on the monolayer.    
   
   
       36 . The method of  claim 35 , wherein forming the monolayer on the conductive electrode comprises: 
 forming a monolayer of a hydrophobic material on the conductive electrode.    
   
   
       37 . The method of  claim 35 , wherein forming the monolayer on the conductive electrode comprises: 
 forming a monolayer of a hydrophilic material on the conductive electrode.    
   
   
       38 . A method comprising: 
 attaching a polyvinylalcohol hydrogel sample having a mass to a conductive electrode formed on a substrate;    serially placing the substrate in a plurality of closed containers, each of the plurality of closed containers having a different humidity level;    measuring the mass of the sample in each of the plurality of closed containers to form a plurality of measurement values; and    calculating an osmotic pressure value for the polyvinylalcohol hydrogel sample from the plurality of measurement values.    
   
   
       39 . A method comprising: 
 identifying a resonant frequency of a substrate having a conductive electrode formed thereon;    attaching a gel-like sample having a mass to the conductive electrode;    measuring a second resonant frequency of the substrate with the sample attached to the substrate; and    calculating the mass of the sample.