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 {snippet name="submission_info"} http://www.mdpi.com/1422-0067/12/9/6194/ Nanotechnology remains the field to explore in the quest to enhance therapeutic efficacies of existing drugs. Fabrication of a methacrylate copolymer-lipid nanoparticulate (MCN) system was explored in this study for oral drug delivery of levodopa. The nanoparticles were fabricated employing multicrosslinking technology and characterized for particle size, zeta potential, morphology, structural modification, drug entrapment efficiency and in vitro drug release. Chemometric Computational (CC) modeling was conducted to deduce the mechanism of nanoparticle synthesis as well as to corroborate the experimental findings. The CC modeling deduced that the nanoparticles synthesis may have followed the mixed triangular formations or the mixed patterns. They were found to be hollow nanocapsules with a size ranging from 152 nm (methacrylate copolymer) to 321 nm (methacrylate copolymer blend) and a zeta potential range of 15.8–43.3 mV. The nanoparticles were directly compressible and it was found that the desired rate of drug release could be achieved by formulating the nanoparticles as a nanosuspension, and then directly compressing them into tablet matrices or incorporating the nanoparticles directly into polymer tablet matrices. However, sustained release of MCNs was achieved only when it was incorporated into a polymer matrix. The experimental results were well corroborated by the CC modeling. The developed technology may be potentially useful for the fabrication of multi-crosslinked polymer blend nanoparticles for oral drug delivery. http://www.mdpi.com/1422-0067/12/9/6194/ Fri, 23 Sep 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-09-23 12 9 Article 6194 6225 1422-0067 Fabrication, Modeling and Characterization of Multi-Crosslinked Methacrylate Copolymeric Nanoparticles for Oral Drug Delivery 2011-09-23 doi: 10.3390/ijms12096194 Ndidi C. Ngwuluka Viness Pillay Yahya E. Choonara Girish Modi Dinesh Naidoo Lisa C. du Toit Pradeep Kumar Valence M.K. Ndesendo Riaz A. Khan http://www.mdpi.com/1422-0067/12/8/4964/ An important property of C60 in aquatic ecotoxicology is that it can form stable aggregates with nanoscale dimensions, namely nC60. Aggregation allows fullerenes to remain suspended for a long time, and the reactivity of individual C60 is substantially altered in this aggregate form. Herein, we investigated the interaction of nC60 and human serum album (HSA) using the methods of fluorescence, fluorescence dynamics, circular dichroism (CD), and site marker competitive experiments. We proposed a binding model consistent with the available experimental results for the interactions of nC60 with HSA. During the interaction process, the structure and conformation of HSA were affected, leading to functional changes of drug binding sites of HSA. http://www.mdpi.com/1422-0067/12/8/4964/ Thu, 04 Aug 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-08-04 12 8 Article 4964 4974 1422-0067 Interaction of Human Serum Album and C60 Aggregates in Solution 2011-08-04 doi: 10.3390/ijms12084964 Maoyong Song Shufang Liu Junfa Yin Hailin Wang http://www.mdpi.com/1422-0067/12/7/4591/ Active targeting could increase the efficacy of anticancer drugs. Methotrexate-human serum albumin (MTX-HSA) conjugates, functionalized by luteinizing hormone-releasing hormone (LHRH) as targeting moieties, with the aim of specifically targeting the cancer cells, were prepared. Owing to the high expression of LHRH receptors in many cancer cells as compared to normal cells, LHRH was used as the targeting ligand in this study. LHRH was conjugated to MTX-HSA nanoparticles via a cross-linker. Three types of LHRH targeted nanoparticles with a mean particle size between 120–138 nm were prepared. The cytotoxicity of LHRH targeted and non-targeted nanoparticles were determined on the LHRH positive and negative cell lines. The internalization of the targeted and non-targeted nanoparticles in LHRH receptor positive and negative cells was investigated using flow cytometry analysis and fluorescence microscopy. The cytotoxicity of the LHRH targeted nanoparticles on the LHRH receptor positive cells were significantly more than non-targeted nanoparticles. LHRH targeted nanoparticles were also internalized by LHRH receptor positive cells significantly more than non-targeted nanoparticles. There were no significant differences between the uptake of targeted and non-targeted nanoparticles to the LHRH receptor negative cells. The active targeting procedure using LHRH targeted MTX-HSA nanoparticles could increase the anti-tumoral activity of MTX. http://www.mdpi.com/1422-0067/12/7/4591/ Fri, 15 Jul 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-07-15 12 7 Article 4591 4608 1422-0067 Enhanced Anti-Tumoral Activity of Methotrexate-Human Serum Albumin Conjugated Nanoparticles by Targeting with Luteinizing Hormone-Releasing Hormone (LHRH) Peptide 2011-07-15 doi: 10.3390/ijms12074591 Azade Taheri Rassoul Dinarvand Fatemeh Atyabi Fatemeh Ahadi Farank Salman Nouri Mohammad Hossein Ghahremani Seyed Nasser Ostad Atefeh Taheri Borougeni Pooria Mansoori http://www.mdpi.com/1422-0067/12/7/4395/ Anticancer drugs, such as paclitaxel (PTX), are indispensable for the treatment of a variety of malignancies. However, the application of most drugs is greatly limited by the low water solubility, poor permeability, or high efflux from cells. Nanoparticles have been widely investigated to enable drug delivery due to their low toxicity, sustained drug release, molecular targeting, and additional therapeutic and imaging functions. This review takes paclitaxel as an example and compares different nanoparticle-based delivery systems for their effectiveness in cancer chemotherapy. http://www.mdpi.com/1422-0067/12/7/4395/ Thu, 07 Jul 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-07-07 12 7 Review 4395 4413 1422-0067 Enabling Anticancer Therapeutics by Nanoparticle Carriers: The Delivery of Paclitaxel 2011-07-07 doi: 10.3390/ijms12074395 Yongjin Liu Bin Zhang Bing Yan http://www.mdpi.com/1422-0067/12/7/4237/ In this study, folic-dextran-camptothecin (Fa-DEX-CPT) tumor-targeted nanoparticles were produced with a supercritical antisolvent (SAS) technique by using dimethyl sulfoxide (DMSO) as a solvent and carbon dioxide as an antisolvent. A factorial design was used to reveal the effect of various process parameters on the mean particle size (MPS) and morphology of the particles formed. Under the optimum operation conditions, Fa-DEX-CPT nanoparticles with a MPS of 182.21 nm were obtained. Drug encapsulation efficiency and loading efficiency were 62.13% and 36.12%, respectively. It was found that the concentrations of the camptothecin (CPT) and dextran solution had a major influence upon morphology and shape of the final product. In addition, the samples were characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) with the purpose of developing a suitable targeted drug delivery system for cancer chemotherapy. http://www.mdpi.com/1422-0067/12/7/4237/ Tue, 28 Jun 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-06-28 12 7 Article 4237 4249 1422-0067 A Novel Preparation Method for Camptothecin (CPT) Loaded Folic Acid Conjugated Dextran Tumor-Targeted Nanoparticles 2011-06-28 doi: 10.3390/ijms12074237 Yuangang Zu Dan Wang Xiuhua Zhao Ru Jiang Qi Zhang Dongmei Zhao Yong Li Baishi Zu Zhiqiang Sun http://www.mdpi.com/1422-0067/12/6/3888/ Nanotechnology offers outstanding potential for future biomedical applications. In particular, due to their unique characteristics, hybrid nanomaterials have recently been investigated as promising platforms for imaging and therapeutic applications. This class of nanoparticles can not only retain valuable features of both inorganic and organic moieties, but also provides the ability to systematically modify the properties of the hybrid material through the combination of functional elements. Moreover, the conjugation of targeting moieties on the surface of these nanomaterials gives them specific targeted imaging and therapeutic properties. In this review, we summarize the recent reports in the synthesis of hybrid nanomaterials and their applications in biomedical areas. Their applications as imaging and therapeutic agents in vivo will be highlighted. http://www.mdpi.com/1422-0067/12/6/3888/ Fri, 10 Jun 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-06-10 12 6 Review 3888 3927 1422-0067 Inorganic-Organic Hybrid Nanomaterials for Therapeutic and Diagnostic Imaging Applications 2011-06-10 doi: 10.3390/ijms12063888 Juan L. Vivero-Escoto Yu-Tzu Huang http://www.mdpi.com/1422-0067/12/6/3705/ Nanoparticle technology is being incorporated into many areas of molecular science and biomedicine. Because nanoparticles are small enough to enter almost all areas of the body, including the circulatory system and cells, they have been and continue to be exploited for basic biomedical research as well as clinical diagnostic and therapeutic applications. For example, nanoparticles hold great promise for enabling gene therapy to reach its full potential by facilitating targeted delivery of DNA into tissues and cells. Substantial progress has been made in binding DNA to nanoparticles and controlling the behavior of these complexes. In this article, we review research on binding DNAs to nanoparticles as well as our latest study on non-viral gene delivery using polyethylenimine-coated magnetic nanoparticles. http://www.mdpi.com/1422-0067/12/6/3705/ Tue, 07 Jun 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-06-07 12 6 Review 3705 3722 1422-0067 Application of Magnetic Nanoparticles to Gene Delivery 2011-06-07 doi: 10.3390/ijms12063705 Daisuke Kami Shogo Takeda Yoko Itakura Satoshi Gojo Masatoshi Watanabe Masashi Toyoda http://www.mdpi.com/1422-0067/12/5/3303/ Nanotechnology, along with related concepts such as nanomaterials, nanostructures and nanoparticles, has become a priority area for scientific research and technological development. Nanotechnology, i.e., the creation and utilization of materials and devices at nanometer scale, already has multiple applications in electronics and other fields. However, the greatest expectations are for its application in biotechnology and health, with the direct impact these could have on the quality of health in future societies. The emerging discipline of nanomedicine brings nanotechnology and medicine together in order to develop novel therapies and improve existing treatments. In nanomedicine, atoms and molecules are manipulated to produce nanostructures of the same size as biomolecules for interaction with human cells. This procedure offers a range of new solutions for diagnoses and “smart” treatments by stimulating the body’s own repair mechanisms. It will enhance the early diagnosis and treatment of diseases such as cancer, diabetes, Alzheimer’s, Parkinson’s and cardiovascular diseases. Preventive medicine may then become a reality. http://www.mdpi.com/1422-0067/12/5/3303/ Thu, 19 May 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-05-19 12 5 Review 3303 3321 1422-0067 Nanomedicine: Application Areas and Development Prospects 2011-05-19 doi: 10.3390/ijms12053303 Houria Boulaiz Pablo J. Alvarez Alberto Ramirez Juan A. Marchal Jose Prados Fernando Rodríguez-Serrano Macarena Perán Consolación Melguizo Antonia Aranega http://www.mdpi.com/1422-0067/12/4/2158/ Plantaricin 423, produced by Lactobacillus plantarum, and bacteriocin ST4SA produced by Enterococcus mundtii, were electrospun into nanofibers prepared from different combinations of poly(D,L-lactide) (PDLLA) and poly(ethylene oxide) (PEO) dissolved in N,N-dimethylformamide (DMF). Both peptides were released from the nanofibers with a high initial burst and retained 88% of their original antimicrobial activity at 37 °C. Nanofibers have the potential to serve as carrier matrix for bacteriocins and open a new field in developing controlled antimicrobial delivery systems for various applications. http://www.mdpi.com/1422-0067/12/4/2158/ Tue, 29 Mar 2011 00:00:00 CEST International Journal of Molecular Sciences 2011-03-29 12 4 Article 2158 2173 1422-0067 Release of Bacteriocins from Nanofibers Prepared with Combinations of Poly(D,L-lactide) (PDLLA) and Poly(Ethylene Oxide) (PEO) 2011-03-29 doi: 10.3390/ijms12042158 Tiaan Heunis Osama Bshena Bert Klumperman Leon Dicks 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