http://www.mdpi.com/journal/ijms/special_issues/bioactive_nanoparticles/ Dear Colleagues, Nanomaterials will potentially play an important role in medicine. However, we need to investigate both medicinal benefits and possible toxicity effects of nanoparticles. Furthermore, the increased manufacturing of nanomaterials and the marketing of nanomaterial-based consumer products all raised health concerns. In recent years, researchers are actively engaged in investigating how nanomaterials transport medicines or genes into targeted cells and how nanomaterials interact with protein signaling pathways, interfere cellular functions and various biological machineries. At the same time, technologies and methods are developed to make more biocompatible nanoparticles for medicinal and imaging application. This special issue includes research reports and review articles reflecting progresses and challenges in the dynamic research area. Dr. Bing Yan Guest Editor Submission All papers should be submitted to ijms@mdpi.org. To be published continuously until the deadline and papers will be listed together at the special issue website. Submitted papers should not have been published previously, nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors is available on the Instructions for Authors page. The International Journal of Molecular Sciences is an international peer-reviewed monthly journal published by Molecular Diversity Preservation International. Open Access publication fees are 800 CHF per paper. English correction fees and/or formatting fees (250 CHF) will be added in certain cases (1050 CHF per paper for those papers that require extensive additional formatting and/or English corrections). http://www.mdpi.com/1422-0067/10/10/4198/ The structure and function of an enzyme can be altered by nanoparticles (NPs). The interaction between enzyme and NPs is governed by the key properties of NPs, such as structure, size, surface chemistry, charge and surface shape. Recent representative studies on the NP-enzyme interactions and the regulation of enzyme activity by NPs with different size, composition and surface modification are reviewed. http://www.mdpi.com/1422-0067/10/10/4198/ Mon, 28 Sep 2009 00:00:00 CEST International Journal of Molecular Sciences 2009-09-28 10 10 Review 4198 4209 1422-0067 Regulation of Enzyme Activity through Interactions with Nanoparticles 2009-09-28 doi: 10.3390/ijms10104198 Zhaochun Wu Bin Zhang Bing Yan http://www.mdpi.com/1422-0067/10/5/2348/ Aβ1-40 coated 20 nm gold colloidal nanoparticles exhibit a reversible color change as pH is externally altered between pH 4 and 10. This reversible process may contain important information on the initial reversible step reported for the fibrillogenesis of Aβ (a hallmark of Alzheimer’s disease). We examined this reversible color change by microscopic investigations. AFM images on graphite surfaces revealed the morphology of Aβ aggregates with gold colloids. TEM images clearly demonstrate the correspondence between spectroscopic features and conformational changes of the gold colloid. http://www.mdpi.com/1422-0067/10/5/2348/ Wed, 20 May 2009 00:00:00 CEST International Journal of Molecular Sciences 2009-05-20 10 5 Article 2348 2366 1422-0067 Microscopic Investigation of Reversible Nanoscale Surface Size Dependent Protein Conjugation 2009-05-20 doi: 10.3390/ijms10052348 Kazushige Yokoyama Hyunah Cho Sean P. Cullen Matthew Kowalik Nicole M. Briglio Harold J. Hoops Zhouying Zhao Michael A. Carpenter http://www.mdpi.com/1422-0067/10/5/2336/ The goal of present work was to investigate the use of bioerodible polymeric nanoparticles as carriers of retinoic acid (RA), which is known to induce differentiation of several cell lines into neurons. A novel method, named “Colloidal-Coating”, has been developed for the preparation of nanoparticles based on a copolymer of maleic anhydride and butyl vinyl ether (VAM41) loaded with RA. Nanoparticles with an average diameter size of 70 nm and good morphology were prepared. The activity of the encapsulated RA was evaluated on SK-N-SH human neuroblastoma cells, which are known to undergo inhibition of proliferation and neuronal differentiation upon treatment with RA. The activity of RA was not affected by the encapsulation and purification processes. http://www.mdpi.com/1422-0067/10/5/2336/ Tue, 19 May 2009 00:00:00 CEST International Journal of Molecular Sciences 2009-05-19 10 5 Article 2336 2347 1422-0067 A Novel Method for the Preparation of Retinoic Acid-Loaded Nanoparticles 2009-05-19 doi: 10.3390/ijms10052336 Cesare Errico Matteo Gazzarri Federica Chiellini