Purdue Research Foundation

Osman Basaran

Kinam Park

David H Thompson

Gil U Lee

Yoon Yeo

Christine A Hrycyna

Alvin Un-Teh Chen

Alvin U Chen

Hansol Wee

Qi Xu

Brayden W Wagoner

Pritish M Kamat

Vishrut Garg

Igal Szleifer

A method is provided for determining the surface viscosity of a liquid in which a thread is formed from a drop of the liquid. The thread is lengthened and its minimum radius his determined at multiple times between the thread formation and thread pinch-off. The minimum radius and associated time values are used to determine a linear relationship of minimum radius and time, with the coefficient of the linear relationship, or the slope X of the line in the linear relationship, corresponding to the surface viscosity μof the liquid according to one of the following equations: where B=μ/μR in which his defined as above, R is the dimension of the feature on which the drop is provided and μ is the bulk viscosity of the liquid, or in which Oh=μ/√{square root over (ρRσ)}, where μ and R are as defined above, ρ is the density of the liquid, and σ is the surface tension of the liquid without surfactants.

Instrument and method for accurate measurement of surface viscosity of viscous liquid

Apparatus and methods for producing a drop from a Drop on demand (DOD) dispenser, the drop having a radius that is much smaller than the radius of the nozzle that expels the drop. Generally, the Ohnesorge number is less than about 0.1. Various embodiments of the invention are found within a four dimensional space defined in terms of the Ohnesorge number, the Weber number, the actuation frequency, and the initial conditions.

Method for producing ultra-small drops

Bioanalytical device that includes a biofunctional component and an optional sensor component. The device includes arrays of addressable, durable, asymmetric biofunctional membranes containing protein transducers capable of unidirectional transport of analytes. Suitable protein transducers include members of the ATP-binding cassette family, such as P-glycoprotein.

Device and bioanalytical method utilizing asymmetric biofunctionalized membrane

A solvent exchange method is employed to provide microencapsulated compositions, such as microcapsules of pharmaceutical preparations. The method is based on an exchange of water and a hydrophilic organic solvent, whereby a decline in solvent quality for the organic solvent causes a polymer dissolved therein to be deposited onto an aqueous core. Optimal results are rationalized in terms of a balance of water solubility and surface tension for the organic solvent. In a preferred embodiment, microcapsules of selected drugs are formed by contacting microdroplets of an aqueous solution containing the drug with the organic solvent containing a polymer dissolved therein. A preferred method employs biodegradable poly(lactic acid-co-glycolic acid) (PLGA) dissolved in acetic acid, ethyl acetate, methyl acetate, or ethyl formate, to form a PLGA membrane around an aqueous drug core. The method is particularly attractive for encapsulating protein-based drugs without substantial denaturation.

Microencapsulation of drugs by solvent exchange

A method and apparatus for dispensing fluid from a drop-on-demand (DOD) fluid dispenser. The method involves withdrawing fluid in the dispenser for a first duration of time, followed by a second duration of time during which the fluid is propelled toward the orifice of the dispenser. Following the period during which the fluid is propelled, there is a second withdrawing of the fluid into the dispenser. The duration of the propelling period is shorter than the duration of either the first withdrawing or the second withdrawing. The propelling of the fluid results in the extension of a small tongue of fluid from the meniscus of the fluid. The second withdrawing of the fluid results in a retraction of the meniscus into the passageway such that only the small tongue of fluid separates and is ejected from the dispenser.

Method and apparatus for producing drops using a drop-on-demand dispenser

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West Lafayette, IN, United States of America

Osman Basaran