Designing Cell-Compatible Hydrogels for Biomedical

Applications

GROUP 6

Anthony Scheller Lamees Elnihum

Kyle BellevilleMichael Li

http://cdn.arstechnica.net/wp-content/uploads/2012/06/hydrogels.jpg

Colorful hydrogels!

Abstract

http://sticky.kaist.ac.kr/menu2/menu3.php

The many uses of hydrogels!

Hydrogels will provide new and improved methods of regenerative medicine, biotechnology, pharmacology, and biosensors in the near future 

Hydrogels can influence cell behavior by mimicking the extracellular matrix

Hydrogels can influence the cell behavior and its biochemical and biophysical processes

IntroductionHydrogels

Polymer chains that are typically hydrophilic, usually highly absorbent and very flexible

Hold potential in biomedical field due to water-carrying capacity Can hold up to 600x their weight

in water!

Can hold many times there weight and flexible!

Can be used in contact lenses

www.stevespanglerscience.com 

www.meyevisionkaty.com 

Numerous applicationsStem CellsTissue EngineeringCell TherapyContact LensesCancer Treatment

From Left to Right: Polymer powder; polymer powder added to a drop of water; hydrogel (after cross-linkage); dehydrated hydrogel (retains overall shape); sesame seed shown for scale

Introduction

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

Water-borne microgels in suspension containing several immobilized molecules – highlights possibilities for injectable hydrogel drug delivery

Introduction

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

“Gel-in-gel” experiment: Hydrogels can be tested to determine if they are sustainable inside other hydrogels

Introduction

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

A microgel containing fluorescently labeled cells – highlights potential uses in cell delivery for tissue regeneration

Introduction

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

Encapsulated fibroblast cells – for studying cell behavior; may advance cancer and stem cell research

Introduction

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

Basic Concepts/PrinciplesHydrogels applicable in the

biological and medical fields

http://cdn.arstechnica.net/wp-content/uploads/2010/01/clay_hydrogel.jpg

Hydrogels mimic the extracellular matrix, which naturally provides structural support in a cell & contains human proteins and other fibers

Above: Diagram of the extracellular matrix in which the hydrogel must be able to survive

Basic Concepts/Principles We can design

hydrogels to have specific functions in the body: Achieve specific

interactions between hydrogels and the human body

Typically semi-synthetic hydrogels to allow for natural proteins to help

Research is currently being done to try to develop human- compatible hydrogels at Purdue University

news.uns.purdue.edu

Basic Concepts Is the hydrogel

compatible with the body? Specific molecular

interactions at the cell-material interface

In the 1990’s, natural proteins were used to create a hybrid structure that was able to control certain properties brought about by a synthetic constituent http://www.pharmainfo.net/

files/u4117/ud-hydrogels-20261.jpg

Hydrogels having molecular interactions on the top allows special properties such as ability to hold pigmentation as shown above

Basic ConceptsResearch in the 1990’s

has led to what we have todayMost notably

polyethylene glycol mimicking collagenase substrates found in natural proteins Polyethylene glycol can act

as a collagenase substrate found in extracellular matrix proteins

An advantage of this is that they are very strong and elastic allowing for high chances of survival in the body www.drugfuture.com

Polyethylene Glycol structure and the bottle below of polyethylene glycol allows for numerous advantageous properties

Center: fully hydrated hydrogel (blue) with encapsulated cell (brown)

A: Dense Hydrogel Structure allows for protection from unwanted objects to seep through

B: Porous Hydrogel allows for permeability of objects such as nutrients to flow

C: Self-assembled hydrogel is more automatic for the cell to converge to a practical structure for the any particular environment

D: Fibrous hydrogel allows for structure in the cell.

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

Basic Concepts

“Work Performed”Paper is a discussion on

past projects that have and will help with future development, rather than an analysis of lab work data

More of a focus on development, application, and future research of hydrogels in a medical environment

Paper specifically mentions: Degradation BioadhesionBioactiviyTransportMechanical properties

Hydrogel has many structural properties that allow for its utility

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

http://www.sciencemag.org/content/336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

Chemical properties that allow structural advantages of the hydrogel. All of the letters show the different types of bonds involved in the hydrogel.

BiodegradationEssential for applications that

require a controlled absorptionAchieved by controlling the

amount of hydrolytically liable cross-links in the polymer networkThis results in more efficient

tissue repair Implants with oligopeptides

that have facilitated a reabsorption rate that is relatively close to the normal repair timeline outperformed other material options

Wound care

products used for tissue repairhttp://jan.ucc.nau.edu/~daa/woundproducts/

duoderm.jpg

BioadhesionAllows cells and tissues

to adhere to other components in the body

Important in surgeries and tissue regeneration

Bioadhesive features can be engineered using linker molecules enabling covalent/non-covalent molecular interactions between the implant and surroundings

http://www.sciencemag.org/content/310/5751/1139/F1.large.jpg

•Above: example of studying bioadhesion: Experimentally straining a tissue, skin, muscle, & brain cell to observe and better understand their functions and determine how and what kind of new materials (such as hydrogels) can be made to aid them

Bioadhesion cont.3rd degree burn treatment: Hydrogels help

grow new, scar-free skin

http://nextbigfuture.com/2011/12/in-third-degree-burn-treatment-hydrogel.html

BioactivityBioactivity in hydrogels is useful for materials that

mediate specific biological events in the body based on:Endogenous cell recruitmentLocal morphogenesisControlled cell differentiation

http://coledeforest.com/publications.html

Illustration of process – Isolate cells from body; observe and apply experiments towards cells to better understand them; design new materials such as hydrogels to aid cell function/goal

TransportHydrogel porosity

Can regulate a therapeutic drug’s diffusion through the polymer network depending on the drug’s properties

Important in tissue engineering

Drug molecular size (relatively large or small?)Hydrogel structure can be

engineered to limit mobility and modulate release kinetics

Injectable biomaterials (hydrogels) for tissue

engineeringhttp://ej.iop.org/images/1748-605X/7/2/024104/Full/bmm406403f3_online.jpg

Mechanical PropertiesConvey important

physical cues to cells by mediating:HomeostasisMorphogenesisCell growthContractilityDifferentiationPathophysiology

Hydrogels’ toughness and flexibility can be engineeredIncrease fracture

stiffness vs. retaining water content

Determining hydrogel stiffness based on tissue typehttp://www.excellness.com/background-

en3.html

ConclusionsPaper laid out a path for

future development Good synthesis of past

research papers that helped present the basic understandings of medical applications of hydrogels allowing for development

Discussed specifically how to accomplish future goals with specified attributes

Choosing hydrogels versus other methods based on desired goal

http://www.tebu-bio.com/index.php?module=tech-info&id_cms=117&type_cms=3

AssessmentImprovements

Could have taken into account other properties the medical industry might need in a hydrogel

Discuss the possibility of expanding the use of hydrogels to appeal to a larger market and producing hydrogels on a larger scale

Go into detail of applicationsFollow Up

Lots of future development leading to synthesizing hydrogels and testing them on lab animals, eventually leading to human applications

AnalysisApplications of hydrogels are broadTailoring hydrogels to personal specifications is important in

medical industry

http://www.innovent-jena.de/en/INNOVENT-/Departments/Biomaterials__185/

Hydrogels in a petri dish; synthesis of hydrogels for further testing

Further SuggestionsDiscuss, other than the practical examples

mentioned at the end of the paper, applications of hydrogels

Could use other sources to find out the potentials of tailored hydrogels and their specific uses

Discuss cost and feasibility of certain materialsOptimization of costs, economics

http://www.futurity.org/science-technology/create-retinas-from-%E2%80%98jell-o%E2%80%99/

Colorful hydrogels

A new way to create hydrogels has been developed by immobilizing

different proteins at the same time.

ReferencesArticle citation:

Science, 1 June 2012: Vol. 336 no. 6085 pp. 1124-1128

Article source:http://www.sciencemag.org/content/

336/6085/1124.full.pdf?sid=95c7472c-bef1-44cc-afed-e1144483d428

Other sources:http://arstechnica.com/science/2012/06/

organic-hydrogel-outperforms-typical-carbon-supercapacitors/