Bio-Technology R&D:Bio-Technology R&D:Performance Enhancement & Innovative

Product Development Through Pore Structure

Akshaya Jena and Krishna GuptaPorous Materials, Inc.

Ithaca, NY, USA

Dependence of Performance on Dependence of Performance on Pore Structure Characteristics Pore Structure Characteristics Many innovative products are currently being

increasingly used in biotech industries including;◦ Health care◦ Medical◦ Pharmaceutical

Examples of such products;◦ Substrates for tissue growth◦ Drug delivery systems◦ Implants◦ Wound dressings◦ Arterial grafts◦ Filters for separation of bacteria from body fluids, ◦ Substrates for organ culture

Pore structure of these products governs the flow and the kinetics of the bio-chemical processes which occur during applications

Dependence of Performance on Dependence of Performance on Pore Structure Characteristics Pore Structure Characteristics

Performance dependent on their pore structure characteristic

Influence of application

environment on pore structure

needs to be determined◦ Chemical environment◦ Operating temperature◦ Humidity◦ Stresses generated during

the operation

Pore structure Pore structure characteristics which need characteristics which need

to be determined:to be determined:Pore diameter

Through pore throat diameter

Pore distribution

Pore volume

Porosity

Pore surface area

Hydrophobic and hydrophilic nature of pores

Gas and liquid permeability

Water vapor transmission rate

Diffusional flow rate

Techniques for Measurement Techniques for Measurement of Pore Structure Characteristicof Pore Structure Characteristic

Many techniques are available for evaluation of pore structure characteristics relevant for bio-technical applications

Techniques for Measurement Techniques for Measurement of Pore Structure Characteristicof Pore Structure Characteristic

Liquid Extrusion Porosimetry◦Measures

Through pore volumeThrough pore diametersPore distributionHydrophobic through poresHydrophilic through poresStructure over a range of:oTemperatureoStressoChemical environmentoControlled humidity

Capillary Flow Porometry◦ Measures

Wide range of through pore throat diametersPore distributionGas permeabilityStructure over a range of

Temperature Stress Chemical environment Controlled humidity

Permeametry◦ Measures

Gas, vapor, and liquid transmission ratesMany chemical speciesOver wide range of concentration, temperature, and

stress on the sample

Techniques for Measurement Techniques for Measurement of Pore Structure Characteristicof Pore Structure Characteristic

Water Vapor and Gas Transmission AnalysisoMeasures

Water vapor transmission rateUses many gradient:

oHumidityo TemperatureoConcentrationo Pressure

VacuaporeoMeasures

Through and blind hydrophobic pore volumeThrough and blind hydrophobic pore diameterDistribution of hydrophobic pores

Techniques for Measurement Techniques for Measurement of Pore Structure Characteristicof Pore Structure Characteristic

Mercury Intrusion Porosimetry◦ Measures

Through and blind pore volume and diameter BET Sorptometry◦ Measures

Surface area of through and blind poresVery small through and blind pore volumePore diameter and distributionChemisorptions of many chemicals over a wide

range of temperatures and pressures Pycnometry◦ Measures

True and bulk density

Techniques for Measurement Techniques for Measurement of Pore Structure Characteristicof Pore Structure Characteristic

How Can PMI Help?How Can PMI Help?

What is PMI?

◦Porous Materials, Inc. designs, manufactures, and sells instruments for pore structure characterization

◦Has vast experience in patenting of novel technology for pore structure characterization and developing custom instruments for a wide variety of applications

How Can PMI Help?How Can PMI Help?

What is PMI?◦Has published many papers and

presented many oral and poster papers in conferences on pore structure characterization of the products of biotech industries

◦Has supplied instruments to many biotech related industries and research laboratories all over the globe

Pore Structure Pore Structure Characterization Instruments Characterization Instruments

by PMIby PMI

PMI Liquid Extrusion Porosimeter

PMI Advanced Capillary Flow Porometer

Specially designed for

biotech industryoWide range of through poresoWide range of sample sizes including miniature samples

Pore Structure Pore Structure CharacterizationCharacterization

Instruments by PMIInstruments by PMI

Water Vapor & Gas Diffusion Analyzers & Permeameters

Unique products widely used in the biotech industry

PMI Vacuapore

PMI Mercury Intrusion Porosimeter

Pore Structure Pore Structure CharacterizationCharacterization

Instruments by PMIInstruments by PMI

Suitable for analysis of hydrophobic and hydrophilic pores

Pore Structure Characterization Pore Structure Characterization Instruments by PMIInstruments by PMI

Gas Pycnometer BET Sorptometer

All instruments needed to investigate pore structure in the biotech

industry are manufactured by PMI.

All PMI Instruments Fully All PMI Instruments Fully AutomatedAutomatedFully automated◦Test execution◦Data acquisition◦Data storage◦Data reduction

Windows-based, menu driven, simple operation

Objective, accurate reproducible results

PMI In-House Contract PMI In-House Contract Testing LaboratoryTesting Laboratory

Performs tests on biotech samples submitted from all over the globe

Test time can be as short as two days

Example of Application Example of Application of PMI Instrumentsof PMI Instruments

Pore Structure Characterization of Substrates for Tissue Growth and Culture

Through Pore VolumeThrough Pore Volume

Instruments used to measure through pore volume◦ PMI Liquid Extrusion Porosimeter

Only through pores relevant for biotechnology measured

Large 500 m pores measureable Highly repeatable Click here for more information on this topic

Through Pore DistributionThrough Pore Distribution Instruments

used to measure through pore distribution◦ Volume

distribution of the through pores: PMI Liquid Extrusion Porosimeter

◦ Volume distribution of through and blind pores: PMI Mercury Intrusion Porosimeter

Expected identical pore volume by both methods (No blind pore in nanofiber substrate)

Expected high Porosity, 81.7% Much higher resolution by liquid

extrusion technique High pressures and toxic mercury

completely avoided by extrusion technique

Characteristics of Through Characteristics of Through Pore Throat DiametersPore Throat DiametersThrough pore throat diameters

determine nutrient and drug permeation rate and govern separation of entities like bacteria from body fluids, drugs, drinking water, food and beverages.

Instrument used to measure through pore throat diameters : PMI Capillary Flow Porometer◦ Measures

The largest pore throat diameterMean flow pore throat diameterPore distribution

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Narrow distribution demonstrated (The largest throat diameter is 2.91 m and the mean is 1.65 m )

The flow based mean throat diameter (1.65 m) is close to the volume based median pore diameter (3.27 m)

Results suggest inappreciable change in pore diameter along pore path

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Characteristics of Through Characteristics of Through Pore Throat DiametersPore Throat Diameters

Distribution of through pore throat diameters in a nanofiber coated substrate

Liquid PermeabilityLiquid Permeability

Permeability helps accessibility of fluids for tissue in-growth

Instrument used for permeability: PMI Liquid Permeameter

Excellent tissue in-growth in high

permeable reticulated foam substrate

Mean Flow Pore DiameterMean Flow Pore Diameter

Critical flow rates and pore diameters govern tissue in-growth

Mean pore diameter measured by: PMI Capillary Flow Porometer

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0 0.5 1 1.5 2 2.5 3 3.5

(Liq. Perm Darcy)/(MFPD microns)

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Series1

Linear (Series1)

Correlation between percent tissue in-growth

and ratio of liquid permeability and mean flow pore diameter for a

laser consolidated metal implant

Special NeedsSpecial NeedsYou can visit our website to see

the wide spectrum of pore structure capability that our instruments offer

If you have a special need that is not part of PMI’s standard test list, the engineers at PMI will be happy to talk to you about your testing requirements and come up with a suitable solution