Patterned and switchable surfaces for biomaterial applications

More documents

Recommendations

Info

CHAPTER 6.OVERALL CONCLUSIONS6.6An increased understanding of the behaviour of biomolecules at surfaces coupledwith the continued development of tools for the advanced surface manipulation ofbiomolecules is imperative for studying complex biological systems or developingadvanced biomedical devices. One particularly useful approach to achievingadvanced biomolecular surface manipulation is the production of patterned orswitchable surfaces, which has been the focus of this thesis. A number of techniqueshave been developed to achieve these abilities, however, the most interesting anduseful systems are those that combine patterns on the micro- or even nanoscale withswitchable architectures to achieve both temporal and spatial control overbiomolecule surface interactions concurrently.Two examples of patterned and switchable systems have been described in thisthesis. The first system, described in CHAPTER 2, included the formation ofpatterned surface chemistries, which were able to spatially organise the adsorption ofDNA and cells for the formation of microarrays (section 2.3.2 and 2.3.4), combinedwith a switchable electrical bias generated on the application of a positive or negativevoltage to the substrate surface. A negative electrical bias stimulated DNAdesorption and enhanced solid phase transfection efficiency (section 2.3.2 and 2.3.3).The second patterned and switchable system reported in this thesis was theformation of a PNIPAAm microarray (section 5.4.1). Here, surface patterning wasachieved by robotic contact printing of PNIPAAm spots onto a low fouling coating.Switching was achieved by a temperature change exploiting the thermoreversibleproperties of PNIPAAm, which is adherent for biomolecules above its LCST andnon-adherent below the LCST. Although not explored in great depth in this thesis,6-208
Andrew Hook – Patterned and switchable surfaces for biomaterial applicationsthis system has also been explored for cell attachment studies, as discussed in section1.3.2, and promises to be a powerful approach to constructing intricate cellarchitectures, which is particularly relevant for tissue engineering applications.Concomitant with the importance of patterned and switchable elements forbiomedical applications is a need to understand in detail the mechanisms ofbiomolecular behaviour at surfaces. This was the focus of CHAPTER 3 andCHAPTER 5, and was exemplified by the discovery of a number of unexpectedmechanisms, consistent with the complex nature of biology at interfaces.Initially, allylamine plasma polymer (ALAPP) coatings were utilised for TCMapplications because of their amine functionality, which was thought to enableelectrostatic interactions with negatively charged DNA and also with the plasmamembrane of cells (section 2.3.2). However, in addition to electrostatic interactionsplaying a role, resulting in enhanced DNA adsorption at low pH and high saltconcentration (section 3.3.3) (discussed in section 1.1.2), further investigationsuggested hydrophobic interactions dominated DNA adsorption at physiological pH(section 3.3.3). This result suggested the partial denaturation of the DNA strand uponadsorption in order to expose the hydrophobic core to hydrophobic moieties on theALAPP coating. DNA adsorption may also be stabilised by electrostatic interactionsbetween isolated positive surface charges and the anionic charge on DNA despite theoverall negative surface charge of ALAPP, as discussed in section 1.1.2. Thishighlights the need to consider specific domains of a biomolecule in addition to itsoverall properties in order to understand the adsorption behaviour of thebiomolecule.Counterintuitive behaviour was also observed for collagen (CN) type I andfibronectin (FN) adsorption to poly(acrylic acid) (PAA) coatings (section 5.4.3).6-209
Page 1 and 2:
Patterned andswitchable surfacesfor
Page 3 and 4:
TABLE OF CONTENTSTABLE OF CONTENTS
Page 5 and 6:
Andrew Hook - Patterned and switcha
Page 7 and 8:
Page 9 and 10:
Page 12 and 13:
CHAPTER 1.INTRODUCTION1The content
Page 14 and 15:
Chapter 1 - Introductionconsiderabl
Page 16 and 17:
Chapter 1 - Introductioninteraction
Page 18 and 19:
Chapter 1 - IntroductionIn general,
Page 20 and 21:
Chapter 1 - IntroductionFor some ap
Page 22 and 23:
Chapter 1 - Introductionangles rang
Page 24 and 25:
Chapter 1 - Introductionof understa
Page 26 and 27:
Chapter 1 - IntroductionSeveral str
Page 28 and 29:
Chapter 1 - Introductioncues to con
Page 30 and 31:
Chapter 1 - Introductionby controll
Page 32 and 33:
Chapter 1 - Introduction1.2.2. Soft
Page 34 and 35:
Chapter 1 - Introductionsubstrate.
Page 36 and 37:
Chapter 1 - Introduction(A)(B)Figur
Page 38 and 39:
Chapter 1 - Introduction(A)(B)(C)(C
Page 40 and 41:
Chapter 1 - Introductioncomplex gen
Page 42 and 43:
Chapter 1 - Introductionmorphology
Page 44 and 45:
Chapter 1 - Introduction(A)(B)(C)(D
Page 46 and 47:
Chapter 1 - Introductionthe LCST, a
Page 48 and 49:
Chapter 1 - IntroductionHyun et al.
Page 50 and 51:
Chapter 1 - Introductionmicelles. T
Page 52 and 53:
Chapter 1 - Introduction1.4.1. DNA
Page 54 and 55:
Chapter 1 - IntroductionA major pro
Page 56 and 57:
Chapter 1 - Introductionattached to
Page 58 and 59:
Chapter 1 - IntroductionTable 1.1.
Page 60 and 61:
Chapter 1 - Introductionefficiencie
Page 62 and 63:
Chapter 1 - Introductionachieved by
Page 64 and 65:
Chapter 1 - IntroductionTable 1.2.
Page 66 and 67:
Chapter 1 - IntroductionOnce releas
Page 68 and 69:
Chapter 1 - Introductionimaging not
Page 70 and 71:
Chapter 1 - IntroductionA number of
Page 73 and 74:
CHAPTER 2.SPATIALLY CONTROLLED ELEC
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
CHAPTER 3.COMPARISON OF THE BINDING
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
DNA (mg/m 2 ) DNA (mg/m 2 )Andrew H
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
DNA (mg/m 2 )Andrew Hook - Patterne
Page 133 and 134:
Page 135 and 136:
Page 137:
Page 140 and 141:
Chapter 4 - Formation of a chemical
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 165 and 166:
CHAPTER 5.SURFACE PLASMON RESONANCE
Page 167 and 168: Andrew Hook - Patterned and switcha
Page 181 and 182: SPR signal intensity (counts)Andrew
Page 193 and 194: Reflectivity (%) Reflectivity (%)An
Page 195 and 196: Reflectivity (%)SPR signal intensit
Page 197 and 198: SPR signal intensity (counts)Andrew
Page 205 and 206: Thickness (nm)Thickness (nm)Thickne
Page 220 and 221: Chapter 6 - Overall conclusionsThes
Page 222 and 223: Chapter 6 - Overall conclusionsnew
Page 232 and 233: Force (nN)Force (nN)Force (nN)Force
Page 234 and 235: Force (nN)Force (nN)Andrew Hook - P
show all

Patterned and switchable surfaces for biomaterial applications

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?