Biomedical Engineering Reference
In-Depth Information
6
EmergingMicroscaleTechnologiesfor
Global
He
alth:CD4
+
Counts
ShuQiWang,
1
FengXu,
1
AlexanderIp,
1
HasanOnurKeles,
a
andUtkanDemirci
1,2
1
CenterforBiomedicalEngineering,DepartmentofMedicine,Brighamand
Women'sHospital,HarvardMedicalSchool,Boston,Massachusetts,USA
2
Harvard-MIT Health Sciences and Technology, Cambridge, Massachusetts, USA
CONTENTS
6.1. Introduction......................................................................................................................... 127
6.2. Flow.Cytometry.for.CD4
+
.Cell.Counts.in.Resource-Limited.Settings....................... 128
6.2.1. Gold.Standard.in.Resource-Limited.Settings.................................................... 128
6.2.2. Simpliied.Flow.Cytometry.for.CD4
+
.Cell.Count.in.Resource-Limited.
Settings..................................................................................................................... 129
6.2.3. Manual.CD4
+
.Cell.Counting.Methods.in.Resource-Limited.Settings............ 130
6.3. Advances.in.Microluidics.and.Imaging.Technologies.for.POC.CD4
+
.Testing......... 132
6.3.1. Design.of.CD4.Microluidic.Chips....................................................................... 132
6.3.2. Microscopy-Based.Detection.and.Counting....................................................... 133
6.3.3. Impedance.Sensing................................................................................................ 134
6.3.4. Lensless.Imaging.................................................................................................... 134
6.3.5. Single-Platform.Image.Cytometer.(SP.ICM)....................................................... 135
6.4. Conclusion.and.Future.Prospects.................................................................................... 136
Acknowledgments....................................................................................................................... 136
References..................................................................................................................................... 136
6.1 Introduction
Globally,.HIV-1.has.caused.25.million.deaths.and.another.33.million.infections,.mostly.
occurring.in.sub-Saharan.Africa.
1
.To.curb.the.HIV/AIDS.epidemic.and.improve.the.qual-
ity.of.life.of.AIDS.patients,.antiretroviral.treatment.(ART).has.been.rapidly.expanded.in.
developing.countries..Despite.these.efforts,.there.were.only.4.million.AIDS.patients.on.
treatment.by.the.end.of.2008,.accounting.for.only.42%.of.AIDS.patients.who.urgently.
need.ART.
3
.The.main.reason.for.this.is.the.lack.of.cost-effective.and.easy-to-use.ART.
monitoring.tools.in.resource-limited.settings..In.industrialized.countries,.ART.is.closely.
monitored.for.immunological.recovery.(CD4
+
.cell.count,.every.3-4.months),.virological.
failure. (two. consecutive. viral. loads. >. 50. copies/ml),. and. drug. resistance.
4,5
. However,.
these. assays. require. expensive. instruments,. air. conditioning,. and. skillful. operators..
In. contrast,. ART. in. developing. countries. is. often. monitored. by. the. World. Health.
Organization. (WHO). clinical. staging. and. CD4
+
. T. lymphocyte. counts.
6
. In. rural. areas,.
blood. samples. are. often. collected. at. local. clinics. and. sent. to. centralized. laboratories..
127
