1、Designation: F 1877 05Standard Practice forCharacterization of Particles1This standard is issued under the fixed designation F 1877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses
2、 indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers a series of procedures for charac-terization of the morphology, number, size, and size distribu-tion of particles. The methods utiliz
3、ed include sieves, optical,SEM, and electrooptical.1.2 These methods are appropriate for particles produced bya number of different methods. These include wear testmachines (Test Method F 732), total joint simulation systems(Guides F 1714 and F 1715), abrasion testing, methods forproducing particula
4、tes, such as shatter boxes or pulverizors,commercially available particles, and particles harvested fromtissues in animal or clinical studies.1.3 The debris may include metallic, polymeric, ceramic, orany combination of these.1.4 The digestion procedures to be used and issues ofsterilization of retr
5、ieved particles are not the subject of thispractice.1.5 A classification scheme for description of particle mor-phology is included in Appendix X3.1.6 As a precautionary measure, removed debris fromimplant tissues should be sterilized or minimally disinfected byan appropriate means that does not adv
6、ersely affect theparticulate material. This standard does not purport to addressall of the safety concerns, if any, associated with its use. It isthe responsibility of the user of this standard to establishappropriate safety and health practices and determine theapplicability of regulatory limitatio
7、ns prior to use.2. Referenced Documents2.1 ASTM Standards:2C 242 Terminology of Ceramic Whitewares and RelatedProductsC 678 Test Methods for Particle Size Distribution of Alu-mina or Quartz by Electric Sensing Technique3E11 Specification for Wire Cloth and Sieves for TestingPurposesE 161 Specificati
8、on for Precision Electroformed SievesE 766 Practice for Calibrating the Magnification of Scan-ning Electron MicroscopesE 1617 Practice for Reporting Particle Size Characteriza-tion DataF 561 Practice for Retrieval and Analysis of ImplantedMedical Devices, and Associated TissuesF 660 Practice for Com
9、paring Particle Size in the Use ofAlternative Types of Particle CountersF 661 Practice for Particle Count and Size DistributionMeasurement in Batch Samples for Filter Evaluation Usingan Optical Particle Counter3F 662 Test Method for Measurement of Particle Count andSize Distribution in Batch Samples
10、 for Filter EvaluationUsing an Electrical Resistance Particle Counter3F 732 Test Method for Wear Testing of Polymeric Materialsfor Use in Total Joint ProsthesesF 1714 Guide for Gravimetric Wear Assessment of Pros-thetic Hip Designs in Simulator DevicesF 1715 Guide for Wear Assessment of Prosthetic K
11、neeDesigns in Simulator Devices3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 agglomerate, na jumbled mass or collection of twoor more particles or aggregates, or a combination thereof, heldtogether by relatively weak cohesive forces caused by weakchemical bonding or an elect
12、rostatic surface charge generatedby handling or processing.3.1.2 aggregate, na dense mass of particles held togetherby strong intermolecular or atomic cohesive forces that isstable to normal mixing techniques, including high-speedstirring and ultrasonics.3.1.3 aspect ratio (AR), na ratio of the majo
13、r to the minordiameter of a particle, which can be used when the major axisdoes not cross a particle outline (see 11.3.3).1This practice is under the jurisdiction ofASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.16 on Biocompatibil
14、ity Test Methods.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1998. Last previous edition approved in 2003 as F 1877 98 (2003)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annu
15、al Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States
16、.3.1.4 elongation (E), nratio of the particle length to theaverage particle width (see 11.3.4).3.1.5 equivalent circle diameter (ECD), na measure of thesize of a particle (see 11.3.2 and Appendix X1).3.1.6 Feret diameter, nthe mean value of the distancebetween pairs of parallel tangents to a project
17、ed outline of aparticle.3.1.7 flocculate, na group of two or more attached par-ticles held together by physical forces, such as surface tension,adsorption, or similar forces.3.1.8 form factor (FF), na dimensionless number relatingarea and perimeter of a particle, as determined in 11.3.6.3.1.9 irregu
18、lar, adja particle that cannot be described asround or spherical. A set of standard nomenclature and refer-ence figures are given in Appendix X2.3.1.10 particle, nthe smallest discrete unit detectable asdetermined in test methods. A nanoparticle has at least onedimension less than 100 nm.3.1.11 part
19、icle breadth, ndistance between touch pointsof the shortest Feret pair, orthogonal to length.3.1.12 particle length, ndistance between touch points ofmaximum Feret pair. This value will be greater than or equal tothe maximum Feret diameter.3.1.13 rectangular, adja particle that approximates asquare
20、or rectangle in shape.3.1.14 roundness (R), na measure of how closely anobject represents a circle as determined in 11.3.5.3.1.15 spherical, adja particle with a generally sphericalshape that appears round in a photograph.4. Summary of Practice4.1 Particles produced by implant wear in vivo in animal
21、 orclinical studies are harvested from tissues after digestionutilizing methods, such as those in Practice F 561. Particlesgenerated in vitro, or obtained from commercial sources, areused as received, or after digestion, if they were generated inprotein solutions, and further separation if there are
22、 signs ofaggregation. A two level analysis is provided. For routineanalysis, the particles are characterized by the terms ofmorphology and by size using Feret diameters. For moredetailed studies, several methods are described that may beutilized for numerically characterizing their dimensions, sized
23、istribution, and number.5. Significance and Use5.1 The biological response to materials in the form of smallparticles, as from wear debris, often is significantly differentfrom that to the same materials as larger implant components.The size and shape (morphology) of the particles may have amajor ef
24、fect on the biological response; therefore, this practiceprovides a standardized nomenclature for describing particles.Such a unified nomenclature will be of value in interpretationof biological tests of responses to particles, in that it willfacilitate separation of biological responses associated
25、withshape from those associated with the chemical composition ofdebris.5.2 The quantity, size, and morphology of particles releasedas wear debris from implants in vivo may produce an adversebiological response which will affect the long term survival ofthe device. Characterization of such debris wil
26、l provide valu-able information regarding the effectiveness of device designsor methods of processing components and the mechanisms ofwear.5.3 The morphology of particles produced in laboratorytests of wear and abrasion often is affected by the testconditions, such as the magnitude and rate of load
27、application,device configuration, and test environment. Comparison of themorphology and size of particles produced in vitro with thoseproduced in vivo will provide valuable information regardingthe degree to which the method simulates the in vivo conditionbeing modeled.6. Interferences6.1 Particles
28、may form aggregates or agglomerates duringpreparation and storage. These would result in an increase inmeasured particle size and decrease in particle number. It isessential that care be taken to resuspend particles prior toanalysis and to note any effects of the dispersant used.6.2 Debris from wear
29、 tests or harvested from tissues maycontain a mixture of materials. Care should be taken to separatethe particles and methods utilized to determine the chemicalcomposition of the particles.6.3 Many automated particle counters operate on the as-sumption that the particles are spherical. These methods
30、 maynot be appropriate for nonspherical debris. Additional methodsshould be used to verify size using methods that take aspectratio into consideration, for example, SEM image analysis.7. Apparatus7.1 Scanning Electron Microscope (SEM) (see PracticeE 766):7.1.1 Standard SEM equipment can be utilized
31、for manystudies. In special instances, such as with polymeric particles,a low acceleration voltage (1-2 kV) machine with a highbrightness electron source, such as a field emission tip, may beutilized.7.1.2 Elemental analysis may be accomplished with anenergy dispersive spectrometer (EDS) for energy
32、dispersiveX-ray analysis (EDXA).7.2 Optical MicroscopeAn optical microscope operatingin the transmission mode may be utilized. Dark field illumina-tion may enhance visualization of some particles. Polarizedlight will facilitate identification of semicrystalline polymericmaterials.7.3 Automatic Parti
33、cle Counters (see Practice F 660):7.3.1 Image AnalyzerThis instrument counts particles bysize as those particles lie on a microscope slide.7.3.2 Optical CounterThis instrument measures the areaof a shadow cast by a particle as it passes a window. From thisarea the instrument reports the diameter of
34、a circle of equalarea.7.3.3 Electrical Resistance CounterThis instrument mea-sures the volume of an individual particle. From that volumethe instrument reports the diameter of a sphere of equal volume(see Test Methods C 678).F18770528. Reagents8.1 Particle-Free (0.2 m Filtered) Deionized Water, forn
35、onpolymeric particles.8.2 Particle-Free (0.2 m Filtered) Methanol or Ethanol,for polymeric or mixed debris.8.3 Ultra-Cleaning Reagent, for apparatus or labware clean-ing.9. Specimen Preparation9.1 Specimens from explanted tissues from animal or clini-cal studies may need to be harvested and digested
36、 usingmethods, such as those described in Practice F 561.9.2 Particles from in vitro cell culture tests also may need tobe digested and harvested.9.3 Centrifugation of particles from wear may be consid-ered, if necessary, at 400 g for 10 min, and resuspended inwater or methanol. Resuspended particle
37、s may be filtered inaccordance with Practice F 561 prior to examination by SEM.10. Particle Imaging by Light or Scanning ElectronMicroscopy10.1 Images may either be captured electronically or pho-tographically for subsequent analysis.10.2 For the characterization and measurements to be accu-rate, it
38、 is essential that the particles be imaged at the largestmagnification as possible. The magnifications in Table 1 arerecommended.10.3 For particle size distribution measurements, divideeach of the size ranges specified in Table 1, into 10 bins.11. Particle Characterization11.1 Particle Shape (Morpho
39、logy)Refer to the photo-graphs and classify the morphology of the particles using thenomenclature in Appendix X2.11.2 Routine Particle Size Determination Using Feret Di-ameters:11.2.1 The use of multiple Feret diameters especially isuseful for spherical and rectangular particles.11.2.2 Determine the
40、 particle size and aspect ratio as themean of two Feret diameters.11.2.3 Calculate the particle size distribution based on thevolume of solution used and the size of the filters.11.3 Detailed Particle Shape Analysis for Irregular ShapedParticles:11.3.1 Five particle dimensional measurements are prov
41、idedusing examples shown in Appendix X1. One is a measure ofparticle size while the other four are shape descriptors.11.3.2 The Equivalent Circle Diameter (ECD) as a Measureof Particle Size:11.3.2.1 The ECD is defined as the diameter of a circle withan area equivalent to the area (A) of the particle
42、 and has theunits of length:ECD 54*A/p!12 (1)11.3.3 The Aspect Ratio (AR) is a Common Measure ofShape:11.3.3.1 The AR is the ratio of the major diameter (dmax)tothe minor diameter (dmin). The major diameter is the longeststraight line that can be drawn between any two points on theoutline. The minor
43、 diameter is the longest line perpendicular tothe major diameter:AR 5 dmax/dmin(2)11.3.4 The elongation (E), is similar to the AR except it ismore suited for the measurement of much longer particles,especially fibrilar particles, where the major axis line does notstay within the particle boundaries.
44、 Refer to particle types Aand C in Appendix X1.11.3.4.1 The E is the ratio of the length (FL) to the breadth(FW):E 5 FL/FW (3)11.3.5 The roundness (R) is a measure of how closely aparticle resembles a circle. The R varies from zero to one inmagnitude with a perfect circle having a value of one.R 5 4
45、A!/p dmax2! (4)where:A = area, anddmax= the maximum diameter.11.3.6 The form factor (FF) is similar to R but is based onthe perimeter (p) of the particle outline rather than the majordiameter. The FF is more sensitive to the variations inroughness of the particle outline.FF 5 4pA/p2(5)where:p = peri
46、meter of the particle outline.11.4 Other Particles Size Determination Methods:11.4.1 Particles larger than 20 m may be determined bysieves described in Specifications E11and E 161.11.4.2 Particles in liquid suspension may be sized as di-rected in Practice F 661 or Test Method F 662.12. Elemental Ana
47、lysis12.1 SEM-EDS analysis should be conducted at a magnifi-cation suggested in 10.2.12.2 Elemental analysis should be conducted for at least 10s for each particle. Since detailed compositional analysis is ofquestionable meaning for micron and submicron sized par-ticles, it is recommended that compo
48、sition be determined basedon identification of key elemental peaks for the major elementslikely to be present in the sample.13. Report13.1 Report the following information (see PracticeE 1617):13.1.1 The source of the particles and materials and meth-ods for generation.13.1.2 Methods utilized to dig
49、est and separate the particles.13.1.3 Morphological description of the particles.13.1.4 Results of particle size and shape analysis.TABLE 1 Recommended Magnifications for Particle ImagingMagnification Particle Size Range (m)10000 0.1 to 1.01000 1 to 10100 10 to 100F187705314. Precision and Bias14.1 The precision and bias of this practice has not beendetermined.15. Keywords15.1 biocompatibility; morphology; particles; SEM; weardebrisAPPENDIXES(Nonmandatory Information)X1. SAMPLE FIGURES FOR CALCULATION OF PARTICLE SIZE AND SHAPEX1.1 See Fig. X1.1.44The examp
