Inorganic-organic systems with tailored properties controlled on molecular, macromolecular and microscopic level

Methods suitable for modification of quartz and glass (plates and beads) on molecular, macromolecular and microscopic levels are described in this pap er. The modifications led to composite materials with the core containing q uartz (fused silica) or glass and outer shells composed of layers of gamma- aminopropyltriethoxysilane (small molecules), dendrimers with aldehyde grou ps (G5) and/or Starburst PAMAM dendrimers with amino groups (macromolecules ), and with one particle thick assemblies of poly(styrene-divinylbenzene-ac rolein) microspheres with aldehyde groups at their surface (microscopic obj ects). Monitoring by AFM quartz plates with immobilized dendrimers revealed that their surfaces are relatively smooth with roughness parameter R-g clo se to 2 nm and with diameters and maximal height of objects covering surfac e in form of bumps close to 4 nm, i.e. to diameters of single macromolecule s of dendrimers. XPS studies of surfaces of modified quartz plates and glas s beads unequivocally confirmed attachment of gamma-aminopropyltriethoxysil ane, dendrimers, and microspheres. Quantitative analysis revealed that dend rimer layers are 3.7 and 3.2 nm thick, for G5 and PAMAM dendrimers, respect ively, indicating that these macromolecules form monolayer structures. XPS and SEM studies of quartz surface covered with layers of gamma-aminopropylt riethoxysilane, G5 and PAMAM denrimers and subsequently with poly(styrene-d ivinylbenzene-acrolein) microspheres indicated that saturation of the surfa ce coverage with these particles is achieved at the degree of coverage clos e to 0.60, i.e. to the maximal value attainable in the case of rapid covale nt immobilization of spherical particles. Surfaces of quartz plates and gla ss beads, with outer layers containing G5 dendrimers and/or poly(styrene-di vinylbenzene-acrolein) microspheres and thus, equipped with aldehyde groups , were used for covalent immobilization of human serum albumin (HSA). AFM s tudies revealed that macromolecules of HSA from dilute protein solution are attached onto surface of G5 dendrimers in such a way that they form cluste rs composed of not less than 50 protein macromolecules each. X-ray photoele ctron spectroscopy used for monitoring of surfaces with immobilized poly(st yrene-divinylbenzene-acrolein) microspheres which were subsequently exposed to contact with solution of HSA revealed that macromolecules of HSA are re adily attached onto immobilized microspheres. (C) 1999 Elsevier Science B.V . All rights reserved.