1、Designation: F1877 05 (Reapproved 2010)Standard Practice forCharacterization of Particles1This standard is issued under the fixed designation F1877; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a series of procedures for charac-terization of the morphology, number, size, and size distribu-tion of particles. The
3、methods utilized 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 F732), total joint simulation systems(Guides F1714 and F1715), abrasion testing, methods forproducin
4、g particulates, 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 ofsterilizat
5、ion of retrieved 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 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 As a precautio
6、nary measure, removed debris fromimplant tissues should be sterilized or minimally disinfected byan appropriate means that does not adversely affect theparticulate material. This standard does not purport to addressall of the safety concerns, if any, associated with its use. It isthe responsibility
7、of the user of this standard to establishappropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C242 Terminology of Ceramic Whitewares and RelatedProductsC678 Test Method for Determination of Particle S
8、ize Dis-tribution of Alumina or Quartz Using Centrifugal Sedi-mentation3E11 Specification for Woven Wire Test Sieve Cloth and TestSievesE161 Specification for Precision Electroformed SievesE766 Practice for Calibrating the Magnification of a Scan-ning Electron MicroscopeE1617 Practice for Reporting
9、Particle Size CharacterizationDataF561 Practice for Retrieval and Analysis of Medical De-vices, and Associated Tissues and FluidsF660 Practice for Comparing Particle Size in the Use ofAlternative Types of Particle CountersF661 Practice for Particle Count and Size DistributionMeasurement in Batch Sam
10、ples for Filter Evaluation Usingan Optical Particle Counter3F662 Test Method for Measurement of Particle Count andSize Distribution in Batch Samples for Filter EvaluationUsing an Electrical Resistance Particle Counter3F732 Test Method for Wear Testing of Polymeric MaterialsUsed in Total Joint Prosth
11、esesF1714 Guide for Gravimetric Wear Assessment of Pros-thetic Hip Designs in Simulator DevicesF1715 Guide for Wear Assessment of Prosthetic KneeDesigns in Simulator Devices33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 agglomerate, na jumbled mass or collection of twoor mor
12、e particles or aggregates, or a combination thereof, heldtogether by relatively weak cohesive forces caused by weakchemical bonding or an electrostatic surface charge generatedby handling or processing.3.1.2 aggregate, na dense mass of particles held togetherby strong intermolecular or atomic cohesi
13、ve forces that isstable to normal mixing techniques, including high-speedstirring and ultrasonics.1This practice is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.16 on Biocompatibility Test Methods.Curren
14、t edition approved June 1, 2010. Published September 2010. Originallyapproved in 1998. Last previous edition approved in 2005 as F1877 051. DOI:10.1520/F1877-05R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo
15、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.3 aspect ratio (AR), na ratio of the major to the minordiameter of
16、a particle, which can be used when the major axisdoes not cross a particle outline (see 11.3.3).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
17、 Feret diameter, nthe mean value of the distancebetween pairs of parallel tangents to a projected 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 dime
18、nsionless number relatingarea and perimeter of a particle, as determined in 11.3.6.3.1.9 irregular, 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 asde
19、termined in test methods. A nanoparticle has at least onedimension less than 100 nm.3.1.11 particle 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
20、equal tothe maximum Feret diameter.3.1.13 rectangular, adja particle that approximates asquare 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
21、 in a photograph.4. Summary of Practice4.1 Particles produced by implant wear in vivo in animal orclinical studies are harvested from tissues after digestionutilizing methods, such as those in Practice F561. Particlesgenerated in vitro, or obtained from commercial sources, areused as received, or af
22、ter digestion, if they were generated inprotein solutions, and further separation if there are 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 me
23、thods are described that may beutilized for numerically characterizing their dimensions, sizedistribution, 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
24、 larger implant components.The size and shape (morphology) of the particles may have amajor effect 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 re
25、sponses to particles, in that it willfacilitate separation of biological responses associated 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 respo
26、nse which will affect the long term survival ofthe device. Characterization of such debris will 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
27、 and abrasion often is affected by the testconditions, such as the magnitude and rate of load 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 t
28、o which the method simulates the in vivo conditionbeing modeled.6. Interferences6.1 Particles 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
29、particles prior toanalysis and to note any effects of the dispersant used.6.2 Debris from wear 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 automate
30、d particle counters operate on the as-sumption that the particles are spherical. These methods 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 Scanni
31、ng Electron Microscope (SEM) (see PracticeE766):7.1.1 Standard SEM equipment can be utilized 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 E
32、lemental analysis may be accomplished with anenergy dispersive spectrometer (EDS) for energy 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. Polarizedl
33、ight will facilitate identification of semicrystalline polymericmaterials.7.3 Automatic Particle Counters (see Practice F660):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 cas
34、t by a particle as it passes a window. From thisarea the instrument reports the diameter of 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 Tes
35、t Methods C678).F1877 05 (2010)28. Reagents8.1 Particle-Free (0.2 m Filtered) Deionized Water, fornonpolymeric 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 Spec
36、imens from explanted tissues from animal or clini-cal studies may need to be harvested and digested usingmethods, such as those described in Practice F561.9.2 Particles from in vitro cell culture tests also may need tobe digested and harvested.9.3 Centrifugation of particles from wear may be consid-
37、ered, if necessary, at 400 g for 10 min, and resuspended inwater or methanol. Resuspended particles may be filtered inaccordance with Practice F561 prior to examination by SEM.10. Particle Imaging by Light or Scanning ElectronMicroscopy10.1 Images may either be captured electronically or pho-tograph
38、ically for subsequent analysis.10.2 For the characterization and measurements to be accu-rate, it 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 r
39、anges specified in Table 1, into 10 bins.11. Particle Characterization11.1 Particle Shape (Morphology)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
40、 Feret diameters especially isuseful for spherical and rectangular particles.11.2.2 Determine the 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 Sh
41、ape Analysis for Irregular ShapedParticles:11.3.1 Five particle dimensional measurements are providedusing 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
42、ECD is defined as the diameter of a circle withan area equivalent to the area (A) of the particle 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 diame
43、ter is the longeststraight line that can be drawn between any two points on theoutline. The minor 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,espe
44、cially fibrilar particles, where the major axis line does notstay within the particle boundaries. 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 ci
45、rcle. The R varies from zero to one inmagnitude with a perfect circle having a value of one.R 5 4A!/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
46、more sensitive to the variations inroughness of the particle outline.FF 5 4pA/p2(5)where:p = perimeter 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 E11 and E161.11.4.2 Particles in liq
47、uid suspension may be sized as di-rected in Practice F661 or Test Method F662.12. Elemental Analysis12.1 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
48、 ofquestionable meaning for micron and submicron sized par-ticles, it is recommended that composition 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 Practice E1617):13.1.1 The s
49、ource of the particles and materials and meth-ods for generation.13.1.2 Methods utilized to digest 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 100F1877 05 (2010)314. Precision and Bias14.1 The precision and bias of this practice has not beendetermined.15. Keywords15.1 biocompatibility; morphology; particles; SEM; weardebrisAPPENDIXES(Nonmandat
