Tunable hydrogel microparticles
Techniques are provided to produce and use non-spherical colloidal particles with independently tuned size, shape, flexibility, and chemical properties. A pre-polymer mixture for forming hydrogel particles includes a percentage of PEGDA selected to impart a target stiffness to the particles and includes, a percentage of acrylic acid selected to impart an independent target chemical function to the particles. The mixture also includes a percentage of photo-initiator to polymerize PEGDA upon exposure to a light source to impart an independently selected target size or shape or both to the particles.
1. A particle of ring shape comprising:
PEGDA of molecular weight about 700 daltons in an amount of at least 10 percent by volume;
an active substance; and
PEG of molecular weight about 200 daltons,
wherein a total amount of PEG, PEGDA and active substance is from about 30 to about 95 percent by volume of the particle.
2. A particle as recited in claim 1 , wherein the amount of PEGDA is selected to impart to the particle a stiffness in a range corresponding to a range of pressures to move an 8 micron particle through a constriction 4 microns across, wherein the range of pressures is between about 0.05 millimeters of mercury (mmHg) and about 100 mmHg.
3. A particle as recited in claim 1 , wherein the active substance comprises a member of the group comprising drugs, detection labels including fluorophores, acrylic acid and other acrylate chemistries.
4. A particle as recited in claim 1 , wherein the active substance comprises a biodegradable cross-linker molecule.
5. A particle as recited in claim 1 , wherein the particle is bound to a target affinity molecule.
6. A ring shaped hydrogel particle having a diameter of about 3 microns and stiffness of a red blood cell comprising:
PEGDA of molecular weight about 700 daltons in an amount of at least 10 percent by volume;
an active substance; and
PEG of molecular weight about 200 daltons.
7. A ring shaped hydrogel particle as recited in claim 6 , wherein:
a total amount of PEG, PEGDA and active substance is about 65 percent by volume of the particle.
8. A composition comprising a plurality of ring shaped particles, each particle comprising:
PEGDA of molecular weight about 700 daltons in an amount of at least 10 percent by volume;
an active substance; and
PEG of molecular weight about 200 daltons,
wherein a total amount of PEG, PEGDA and active substance is from about 30 to about 95 percent by volume of the particle.
9. A composition as recited in claim 8 , wherein the composition is formulated for administration to an animal.
10. A composition as recited in claim 8 , wherein the animal is a mammal and the particle is administered intravenously, intraarterially, intraperitoneally or in cerebrospinal fluid of the animal.
11. A composition as recited in claim 8 , wherein the composition is formulated for topical administration to an animal.
12. A composition as recited in claim 8 , wherein the composition is formulated as a paint additive.
13. A composition as recited in claim 8 wherein the composition is formulated for animal consumption.
14. A composition as recited in claim 9 , wherein the particle is a ring shaped hydrogel particle having a diameter of about 8 microns and a stiffness of red blood cells.