Miqin Zhang
University of Washington
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Publication
Featured researches published by Miqin Zhang.
Advanced Drug Delivery Reviews | 2008
Conroy Sun; Jerry S. H. Lee; Miqin Zhang
Magnetic nanoparticles (MNPs) possess unique magnetic properties and the ability to function at the cellular and molecular level of biological interactions making them an attractive platform as contrast agents for magnetic resonance imaging (MRI) and as carriers for drug delivery. Recent advances in nanotechnology have improved the ability to specifically tailor the features and properties of MNPs for these biomedical applications. To better address specific clinical needs, MNPs with higher magnetic moments, non-fouling surfaces, and increased functionalities are now being developed for applications in the detection, diagnosis, and treatment of malignant tumors, cardiovascular disease, and neurological disease. Through the incorporation of highly specific targeting agents and other functional ligands, such as fluorophores and permeation enhancers, the applicability and efficacy of these MNPs have greatly increased. This review provides a background on applications of MNPs as MR imaging contrast agents and as carriers for drug delivery and an overview of the recent developments in this area of research.
Advanced Drug Delivery Reviews | 2010
Omid Veiseh; Jonathan Gunn; Miqin Zhang
Magnetic nanoparticles (MNPs) represent a class of non-invasive imaging agents that have been developed for magnetic resonance (MR) imaging. These MNPs have traditionally been used for disease imaging via passive targeting, but recent advances have opened the door to cellular-specific targeting, drug delivery, and multi-modal imaging by these nanoparticles. As more elaborate MNPs are envisioned, adherence to proper design criteria (e.g. size, coating, molecular functionalization) becomes even more essential. This review summarizes the design parameters that affect MNP performance in vivo, including the physicochemical properties and nanoparticle surface modifications, such as MNP coating and targeting ligand functionalizations that can enhance MNP management of biological barriers. A careful review of the chemistries used to modify the surfaces of MNPs is also given, with attention paid to optimizing the activity of bound ligands while maintaining favorable physicochemical properties.
Advanced Drug Delivery Reviews | 2010
Narayan Bhattarai; Jonathan Gunn; Miqin Zhang
Hydrogels are high-water content materials prepared from cross-linked polymers that are able to provide sustained, local delivery of a variety of therapeutic agents. Use of the natural polymer, chitosan, as the scaffold material in hydrogels has been highly pursued thanks to the polymers biocompatibility, low toxicity, and biodegradability. The advanced development of chitosan hydrogels has led to new drug delivery systems that release their payloads under varying environmental stimuli. In addition, thermosensitive hydrogel variants have been developed to form a chitosan hydrogel in situ, precluding the need for surgical implantation. The development of these intelligent drug delivery devices requires a foundation in the chemical and physical characteristics of chitosan-based hydrogels, as well as the therapeutics to be delivered. In this review, we investigate the newest developments in chitosan hydrogel preparation and define the design parameters in the development of physically and chemically cross-linked hydrogels.
Biomaterials | 2002
Yong Zhang; Nathan Kohler; Miqin Zhang
Superparamagnetic magnetite nanoparticles were surface-modified with poly (ethylene glycol) (PEG) and folic acid, respectively, to improve their intracellular uptake and ability to target specific cells. PEG and folic acid were successfully immobilized on the surfaces of magnetite nanoparticles and characterized using fourier transform infrared spectra. The nanoparticle internalization into mouse macrophage (RAW 264.7) and human breast cancer (BT20) cells was visualized using both fluorescence and confocal microscopy, and quantified by inductively coupled plasma emission spectroscopy (ICP). After the cells were cultured for 48 h in the medium containing the nanoparticles modified with PEG or folic acid, the results of fluorescence and confocal microscopy showed that the nanoparticles were internalized into the cells. The ICP measurements indicated that the uptake amount of PEG-modified nanoparticles into macrophage cells was much lower than that of unmodified nanoparticles. while folic acid modification did not change the amount of the uptake. However, for breast cancer cells, both PEG and folic acid modification facilitated the nanoparticle internalization into the cells. Therefore, PEG and folic acid modification of magnetite nanoparticles could be used to resist the protein adsorption and thus avoid the particle recognition by macrophage cells, and to facilitate the nanoparticle uptake to specific cancer cells for cancer therapy and diagnosis.
Biomaterials | 2003
Hassna R. Ramay; Miqin Zhang
A new technique of combining the gel-casting and polymer sponge methods is introduced in this study to prepare macroporous hydroxyapatite scaffolds, which provides a better control over the microstructures of scaffolds and enhances their mechanical properties. With this technique, we were able to produce scaffolds with mechanical and structural properties that cannot be attained by either the polymer sponge or gel-casting method. The scaffolds prepared have an open, uniform and interconnected porous structure with a pore size of 200-400 microm. A compressive yield strength of approximately 5 MPa equivalent to that of cancellous bone and a compressive modulus of approximately 8 GPa similar to that of cortical bone were achieved. The pore morphology, size, and distribution of the scaffolds were characterized using a scanning electron microscope. X-ray diffraction and Fourier transform infrared spectroscopy were used to determine the crystal structure and chemical composition of scaffolds, respectively. Scaffolds with desired porosity, pore size, and geometry can be prepared by using polymer sponges of appropriate structures.
Accounts of Chemical Research | 2011
Forrest M. Kievit; Miqin Zhang
Nanotechnology provides a flexible platform for the development of effective therapeutic nanomaterials that can interact specifically with a target in a biological system and provoke a desired response. Of the nanomaterials studied, iron oxide nanoparticles have emerged as one of top candidates for cancer therapy. Their intrinsic superparamagnetism enables noninvasive magnetic resonance imaging (MRI), and their biodegradability is advantageous for in vivo applications. A therapeutic superparamagnetic iron oxide nanoparticle (SPION) typically consists of three primary components: an iron oxide nanoparticle core that serves as both a carrier for therapeutics and contrast agent for MRI, a coating on the iron oxide nanoparticle that promotes favorable interactions between the SPION and the biological system, and a therapeutic payload that performs the designated function in vivo. Often, the design may include a targeting ligand that recognizes the receptors over-expressed on the exterior surface of cancer cells. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Thus, the success of a therapeutic SPION largely relies on the design of the iron oxide core to ensure its detection in MRI and the coatings that allow the nanoparticles to bypass these barriers. Strategies to bypass the physiological barriers, such as liver, kidneys, and spleen, involve tuning the overall size and surface chemistry of the SPION to maximize blood half-life and facilitate the navigation in the body. Strategies to bypass cellular barriers include the use of targeting agents to maximize uptake of the SPION by cancer cells and the employment of materials that promote desired intracellular trafficking and enable controlled drug release. The payload can be genes, proteins, chemotherapy drugs, or a combination of these molecules. Each type of therapeutic molecule requires a specific coating design to maximize the loading and to achieve effective delivery and release. In this Account, we discuss the primary design parameters in developing therapeutic SPIONs with a focus on surface coating design to overcome the barriers imposed by the bodys defense system. We provide examples of how these design parameters have been implemented to produce SPIONs for specific therapeutic applications. Although there are still challenges to be addressed, SPIONs show great promise in the successful diagnosis and treatment of the most devastating cancers. Once the critical design parameters have been optimized, these nanoparticles, combined with imaging modalities, can serve as truly multifunctional theranostic agents that not only perform a therapeutic function but also provide instant clinical feedback, allowing the physician to adjust the treatment plan.
Biomaterials | 1998
Miqin Zhang; Tejal A. Desai; Mauro Ferrari
Silicon surfaces were modified by covalent attachment of a self-assembled (SA) polyethylene glycol (PEG) film. Adsorption of albumin, fibrinogen, and IgG to PEG immobilized silicon surfaces was studied by ellipsometry to evaluate the non-fouling and non-immunogenic properties of the surfaces. The adhesion and proliferation of human fibroblast and Hela cells onto the modified surfaces were investigated to examine their tissue biocompatibility. Coated PEG chains showed the effective depression of both plasma protein adsorption and cell attachment to the modified surfaces. The mechanisms accounting for the reduction of protein adsorption and cell adhesion on modified surfaces were discussed.
Journal of Biomedical Materials Research | 2001
Yong Zhang; Miqin Zhang
Chitosan scaffolds reinforced by beta-tricalcium phosphate (beta-TCP) and calcium phosphate invert glass were fabricated with a low-cost, bioclean freeze-drying technique via thermally induced phase separation. The microstructure, mechanical performance, biodegradation, and bioactivity of the scaffolds were studied. The composite scaffolds were macroporous, and the pore structures of the scaffolds with beta-TCP and the glass appeared very different. Both the compressive modulus and yield strength of the scaffolds were greatly improved, and reinforced microstructures were achieved. The bioactivity tests showed a continuous decrease in both Ca and P concentrations of a simulated body fluid (SBF) after the scaffolds with beta-TCP were immersed in the SBF for more than 20 h, which suggests that an apatite layer might be formed on the scaffolds. However, the same was not observed for the pure chitosan scaffolds or the scaffolds incorporated with the glass. This was further confirmed by micrographs from scanning electron microscopy. This study suggests that the desirable pore structure, biodegradation rate, and bioactivity of the composite scaffolds might be achieved through controlling the ratio of chitosan and calcium phosphates or beta-TCP and the glass.
Advanced Materials | 2011
Forrest M. Kievit; Miqin Zhang
Cancer nanotheranostics aims to combine imaging and therapy of cancer through use of nanotechnology. The ability to engineer nanomaterials to interact with cancer cells at the molecular level can significantly improve the effectiveness and specificity of therapy to cancers that are currently difficult to treat. In particular, metastatic cancers, drug-resistant cancers, and cancer stem cells impose the greatest therapeutic challenge for targeted therapy. Targeted therapy can be achieved with appropriately designed drug delivery vehicles such as nanoparticles, adult stem cells, or T cells in immunotherapy. In this article, we first review the different types of nanotheranostic particles and their use in imaging, followed by the biological barriers they must bypass to reach the target cancer cells, including the blood, liver, kidneys, spleen, and particularly the blood-brain barrier. We then review how nanotheranostics can be used to improve targeted delivery and treatment of cancer cells. Finally, we discuss development of nanoparticles to overcome current limitations in cancer therapy.
Cancer Research | 2007
Mandana Veiseh; Patrik Gabikian; S-Bahram Bahrami; Omid Veiseh; Miqin Zhang; Robert C. Hackman; Ali C. Ravanpay; Mark R. Stroud; Yumiko Kusuma; Stacey Hansen; Deborah Kwok; Nina M. Muñoz; Raymond W. Sze; William M. Grady; Norman M. Greenberg; Richard G. Ellenbogen; James M. Olson
Toward the goal of developing an optical imaging contrast agent that will enable surgeons to intraoperatively distinguish cancer foci from adjacent normal tissue, we developed a chlorotoxin:Cy5.5 (CTX:Cy5.5) bioconjugate that emits near-IR fluorescent signal. The probe delineates malignant glioma, medulloblastoma, prostate cancer, intestinal cancer, and sarcoma from adjacent non-neoplastic tissue in mouse models. Metastatic cancer foci as small as a few hundred cells were detected in lymph channels. Specific binding to cancer cells is facilitated by matrix metalloproteinase-2 (MMP-2) as evidenced by reduction of CTX:Cy5.5 binding in vitro and in vivo by a pharmacologic blocker of MMP-2 and induction of CTX:Cy5.5 binding in MCF-7 cells following transfection with a plasmid encoding MMP-2. Mouse studies revealed that CTX:Cy5.5 has favorable biodistribution and toxicity profiles. These studies show that CTX:Cy5.5 has the potential to fundamentally improve intraoperative detection and resection of malignancies.