MPF 604INSTRUCTOR: Dr. C. Kassanga

STUDENTS: Keziah Maina MHA/E/2015/0005 Tipezenji Sakala

MHA/E/2015/0004

Challenges in Collection, Storage and Processing of Biological Samples

OutlineIntroductionSample collectionSample processingSample bankingQuality controlConclusion

Introduction Molecular epidemiology incorporates

epidemiology principles and knowledge of molecular events that lead to disease

It uses the concept of biomarkers to describe the molecular events characteristic for various stages between exposure and disease

A molecular epidemiologic study has various components

IntroductionStudy design

planning phaseDefine sample type

and biomarkers of interest

Pilot study; validate biomarkers, best conditions and factors affecting their stability

Informed consent; for current, future and unforeseen use of samples

Sample CollectionA biospecimen taken by

sampling; a representative of any other specimen taken from the source

Sourcesbody fluids e.g blood,

urineTissuesCultured cellsExfoliated cellsTissue/organ swabs

Challenges on sample collectionInteraction between

study subjects, field personnel and researchersEstablish clear

communication Deliver clear

instructions to staff and study subjects

Reinforced by written protocols and frequent communication

Methods of sample collectionInvasive vs. Non-

invasive methods

TimingMinute-to-minute/ hour-

to-hour variationMetabolic variationPre-clinical disease

Challenges on sample collectionStability of samples

Anticoagulants; some required/better or contraindicated

Stabilizing agents; for unstable biomarkers

Temperature; depend on biomarker of interest

Timing before initial processing; depend on components of interest and their stability

Sterility; esp for RNA isolation and cell culture

Endogenous degrading enzymes; proteins by proteases and RNA by RNAases.

Shipment; Specific regulations , packaging, labeling and documentation of shipped goods

Challenges on sample collectionStrict adherence to

protocolsThe larger the study,

the greater the challenge.

Produce SOPsTraining of all indiv.Ensure strict adherence

Safety; Samples are potentially

infectious personnel training on

safety precautions

Containers/equipmentFor collection,storage and

processingdepends on the sample

volume, means of transfer to the laboratory, cost, storage efficiency, and intended analyses

Paper trail; includes collection details (date,

sample number, type and volume),

shipping information (rcp’ts and tracking nos.) and

chain of custody forms

Sample processingProduces a number of

samples to be analyzed or banked for future use

Variety of processing protocols;Aliquoting and freezingBlood: clot & serumCryopreservation

Sample processing cont’ndMore effective processing, provisions for(1) isolating large quantities of DNA; (2) storing high-quality RNA; (3)using buccal cell DNA, blood clot (or blood smears)for genotyping; (4) separating lymphocyte from granulocyte DNA/RNA; (5) making metaphase spreads (useful for many years); (6) cryopreserving freshly isolated lymphocytes or whole blood to be recultured (7) preparing slides of exfoliated cells

Challenges of Sample processing Time

Some biomarkers may decay soon after collxn

Essential to process asap

On-site processing for preservation e.g aliquoting

SterilityCells for culture

processing or cryopreservation(DMSO, liquid nitrogen)

Record keepingTime schedules

and pre-made tables (# and vol.)

*large quantities

Sample Banking Biological bank or

Biorepository Goal is

Make possible for future analysis for currently unknown biomarkers

Minimizes research costs for future studies

Challenges of Sample bankingPhysical spaceLabelling & data

mg’t; effective trackingBarcodingInventory

management system;Electronic data managment systems (database)

Challenges of Sample banking cont’d

Natural disasters and Equipment failureStore duplicate

aliquotes in different physical location

Deterioration of stored specimens tested on regular

basis

Examples of biobanksEuropean Cancer

BankNational Cancer

Institute BiobankSchool of Public

Health Biorepository, University of California, Berkely

The Future of banking and biodepositories

Nanobarcoding DNA strands form barcode-like latticeNanobarcodes composed of cyclindrically-

shaped ‘stripped’ metal nano-particlesStore a lot of information on small space

CryobanksSamples stored in small plates; many samples

attached to memory chipTemperature electronics and robotics

Completely automated DNA isolation and banking

Quality ControlOverall- system application of optimal

procedures, ensure valid ,reproducible and accurate results

International Organisation of Standardization (ISO) created QMS(quality management systems) standards

International Epidemiology Association(IEA) created GEP(Good Epidemiological Practices).. Quality assurance in epidemiology studies

Quality control cont’ndQuality assurance practices include

SOPs specified for each type of biological sample(QMS-BS); collection, processing, shipping and storage

Document and sample control- ID and tracebilityPurchases and subcontracting- std. materials

usedProcess control- from beginning of study; ID of BS,

steps of collxn, processing, storage, shipment and analysis

Conclusion

Proper handling of biological samples protects quality ofspecimens and validity of results

Advances in molecular genetics can only be taken advantage of if sample quality is assured for already available and future biomarkers

THANK YOU!!!!!